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  • 2000-2004
  • 1995-1999
  • 1990-1994  (4,223)
  • 1890-1899
  • 1992  (4,223)
  • Polymer and Materials Science  (4,164)
  • Historical fiction., gsafd
  • breast cancer
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  • 2000-2004
  • 1995-1999
  • 1990-1994  (4,223)
  • 1890-1899
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  • 1
    ISSN: 1436-2813
    Keywords: breast cancer ; estrogen receptor ; DNA ; ploidy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The relationship of estrogen receptor(ER) status to DNA ploidy was investigated in 121 patients with breast cancer who underwent surgery. Lymph node status was evaluated histologically and ER levels were determined by the dextran-coated charcoal method, with a level of 3 fmol/mg·protein being considered positive. Flow cytometric DNA content was analyzed using paraffin-embedded tissue blocks. Sixty-three per cent of the specimens were ER+, while 37 per cent were negative. Sixty-one patients (50.4 per cent) were diploid and 60 aneuploid. A statistically significant correlation between the ER positivity rate and diploid DNA was found. Higher ER levels were seen in the postmenopausal patients with diploid tumors than in those with aneuploid tumors and there was a significant tendency for ER levels to be higher in the diploid tumors. Nodal status was not correlated with ER positivity or ploidy pattern. The present results indicate that ER levels are correlated with DNA ploidy, and reflect the degree of functional differentiation.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1436-2813
    Keywords: breast cancer ; parasternal lymph node ; extended radical mastectomy ; postoperative irradiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In order to establish a therapeutic approach for primary breast cancer of medial and central origin, we reviewed 183 patients who had been treated by one of the following three modalities at the Second Department of Surgery, Osaka University Medical School between January, 1965 and December, 1980. Group A (n=70): standard radical mastectomy alone; Group B (n=34): standard radical mastectomy followed by postoperative irradiation to the parasternal and supraclavicular regions, and; Group C (n=62): extended radical mastectomy that included removal of the parasternal lymph nodes. The background factors of the three groups were not significantly different. The overall survival five and ten years following surgery in the three groups were 91 per cent and 79 per cent in group A, 82 per cent and 67 per cent in group B, and 82 per cent and 70 per cent in group C, respectively, showing no significant difference in overall survival among the three groups. When the patients were classified according to the extent of axillary lymph node involvement, there was no difference in survival among the three treatments in patients who had less than three lymph node metastases in the axilla. However, treatment of the parasternal lymph nodes improved survival in the patients who had more than four lymph node metastases in the axilla. Parasternal lymph node involvement definitely worsened the prognosis, showing it to be a good prognostic factor. Thus, extended radical mastectomy should be considered for patients with breast cancer of medial or central location, when extended axillary lymph node involvement is found.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1436-2813
    Keywords: prognostic factor ; lymph node metastases ; DNA-ploidy status ; breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We evaluated the relationship between the regional lymph node metastases and the DNA ploidy status in 207 patients with invasive breast cancer, as well as their prognostic values in estimating the prognosis of breast cancer. A significantly higher incidence of aneuploidy was found in patients with a large T3 or T4 tumor, a positive axillary lymph node status, more than 4 positive axillary lymph nodes or positive internal mammary lymph nodes. In a univariate study, the overall survival was significantly correlated with tumor size, axillary lymph node status, axillary and internal mammary lymph node metastases, and DNA ploidy status. In the multivariate analysis, however, only axillary and internal mammary lymph node metastases were recognized as important independent prognostic factors on survival. In this series, the DNA ploidy status did not appear to be an independent prognostic factor either in the entire series or in negative axillary node patients, since it was closely correlated with the axillary or internal mammary lymph node metastases, and the axillary node negative patients had an extremely favorable prognosis.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of behavioral medicine 15 (1992), S. 429-445 
    ISSN: 1573-3521
    Keywords: cancer ; breast cancer ; information seeking ; evaluation ; communication channels
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Psychology
    Notes: Abstract This study examined women's evaluations of communication channels which are major carriers of cancer-related information. A sample of women over 40 (n=395) was asked which channels they had received cancer-related information from within the last year and what their evaluations were of these channels in terms of three dimensions: editorial tone (credibility), communication potential (presentation and style), and utility. Various statistical analyses revealed significant interactions between evaluations and channels and significant main effects for channels and for evaluations. Additional post hoc comparisons suggested that there was a general trend across channel characteristics to rate doctors and organizations more highly than friends/family and the media for providing cancer-related information, although the respondents did not perceive information received from doctors and organizations as more understandable or more novel than information obtained from the media. On the whole, friends and family were evaluated least positively. These results are discussed in terms of their relationship to other programmatic research in this area and their pragmatic implications for future cancer control efforts.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    International journal of anthropology 7 (1992), S. 59-64 
    ISSN: 1824-3096
    Keywords: Dermatoglyphics ; asymmetry ; cleft lip and palate ; Cooley's anemia ; breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The amount of asymmetry in various digital and palmar characters found in healthy and pathological individuals (presenting Cooley's anemia, cleft lip, cleft palate and breast cancer) was examined. Males with cleft palate presented higher asymmetry index values than did healthy males. No great differences were found in the other pathologies, while different behaviour in the two sexes was noted.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1573-0646
    Keywords: multidrug resistance ; toremifene ; breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract The enhanced accumulation of doxorubicin by agents known to reverse multidrug resistance provides a good functional test for evaluating modulating activity. In the present study, the non-steroidal triphenylethylene toremifene selectively increased doxorubicin accumulation in multidrug resistant estrogen receptor negative MDA A-1 human breast cells compared to the MDA 231 wild type cells. MDA A-1 cells were noted to be 1,000 fold resistant to doxorubicin (IC 50=〈 0.1μg/ml MDA 231; IC 50=100μg/ml MDA A-1). Total accumulation of doxorubicin, expressed as area under the time concentration curve (AUC), was increased significantly in doxorubicin resistant cells (156% increase) versus wild type MDA 231 cells (6% increase). Correction of the accumulation defect to doxorubicin in drug resistant cells required a 18–20 hour pre-incubation with toremifene. The effects of toremifene on cell cycle in MDA A-1 cells was analyzed by flow cytometric techniques. Toremifene had a dose response relationship in blocking cells in G0–G1 reducing the number of cells entering S phase of the cell cycle. This effect was maximal at concentrations which increased the accumulation of doxorubicin in MDA A-1 cells. Several metabolites of toremifene were also noted to increase doxorubicin accumulation in MDA A-1 doxorubicin resistant cells. Tore XVIII (deaminocarboxytoremifene), Tore IV (4-hydroxy-N-desmethyltoremifene) and N-desmethyltoremifene all increased the accumulation of doxorubicin significantly (114%, 128% and 42% respectively). Finally, we show evidence that toremifene and its active metabolites are present in high concentrations in human plasma following a single 200 mg oral dose. Toremifene remains a very promising agent for modulating doxorubicin cytotoxicity in multidrug resistance.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1573-7233
    Keywords: prostacyclin ; thromboxane A2 ; 6-keto-PGF1α ; 2,3-dinor-6-keto-PGF1α ; 2,3-dinor-TXB2 ; nafazatrom ; breast cancer ; ovarian cancer ; cervix cancer ; leiomyonas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Studies investigating the role of thromboxane A2 and prostacyclin in cancer of the female breast and genital tract are reviewed. Whereas thromboxane A2 was found to promote the tumour growth and metastasis, prostacyclin exerted a protective effect in maintaining vascular and platelet homeostasis. Thus, monitoring of prostacyclin and thromboxane levels in plasma and urine of cancer patients may be essential for the evaluation of tumour growth and metastasis. Of all modulators of thromboxane and prostacyclin biosynthesis, nafazatrom was found to exhibit promising results for the treatment of advanced breast cancer, although its use in the routine therapy is questionable at this stage.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1573-7225
    Keywords: Age at diagnosis ; breast cancer ; case-control ; diet ; menopause ; Singapore
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A case-control study was conducted among Singapore Chinese women, comprised of 200 histologically confirmed cases of breast cancer and 420 hospital controls. Subjects were interviewed on family history of breast cancer, social and demographic characteristics, reproductive history, and diet one year prior to interview. Differences in risk factors were observed according to menopausal status. In the premenopausal group, the most consistently significant nondietary effect was an increased risk with late age at first birth. In postmenopausal women, the most consistent nondietary effects were increased risks with nulliparity, tall stature, high educational status, and a family history of breast cancer. In premenopausal women, the strongest dietary effects were low risks with high intakes of polyunsaturated fatty acids (PUFA), β-carotene, soya protein as a proportion of all protein, and a high risk with high red-meat intake. No dietary effects were observed in postmenopausal women. Examination of effects by 10-year age groups suggested that the differences in the effects of age at first birth, nulliparity, height, education, β-carotene intake, and PUFA intake between premenopausal and postmenopausal women were at least partly attributable to age-related differences in the baseline distributions of these variables. The variation in the effects of red meat and soya protein appeared to be attributable mainly to menopausal status itself, which is consistent with the hypothesis that these factors operate on risk by way of hormonal mechanisms.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Cancer causes & control 3 (1992), S. 517-525 
    ISSN: 1573-7225
    Keywords: A typical hyperplasia ; breast cancer ; meta-analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: The purpose of this paper is to examine critically the evidence that atypical hyperplasia (AH) is a risk factor for breast cancer. First, we appraised studies that have examined the association between AH and breast cancer risk for their adherence to widely accepted standards for the conduct of research. Second, we examined the a vailable evidence to determine the plausibility of an association between AH and breast cancer risk using the guidelines proposed by Bradford Hill. A total of 18 studies (11 cohort studies, two case-control studies, and five cross-sectional studies) were found that were published in the English language from January 1960 to March 1992 that examined the association of AH as a distinct entity and breast cancer risk. A systematic approach was adopted to examine the collected studies for their adherence to methodologic standards, which showed wide variation among studies. A meta-analysis was carried out, based on a total sample size of 182,980 women. Of 16 studies that gave point estimates of risk, 14 exceeded unity and 12 were significantly different from unity. The pooled estimate from all studies of the association between AH and breast cancer, gave an overall odds ratio (OR) of 3.67 (95 percent confidence interval = 3.16–4.26). The test of the hypothesis of homogeneous association was rejected (χ2 = 151.6, df = 14, P〈0.0001), indicating significant variability among the ORs of individual studies. The conclusions from the application of the Bradford Hill criteria indicated strongly that AH is a risk factor for breast cancer.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 21 (1992), S. 15-26 
    ISSN: 1573-7217
    Keywords: breast cancer ; endocrine therapy ; hormone therapy ; metastases ; review
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary More than 45,000 women will die of metastatic breast cancer in the United States in 1991. Endocrine therapy remains a major option for treatment of such patients, and results in complete plus partial response rates of 30% with a median duration of approximately one year. Postmenopausal status, increased age, a prolonged disease-free interval, bone and soft tissue metastases, and positive estrogen and progesterone receptors are all associated with an increased response to endocrine therapy. The use of additive hormonal therapy, specifically antiestrogens, progestins, and aromatase inhibitors, have replaced surgical ablative procedures in the majority of patients; response rates to antiestrogen therapy, progestin therapy, and aromatase inhibitors are similar, but antiestrogens have generally been associated with the most favorable therapeutic index. At present, there is no convincing evidence that either combinations of endocrine therapies or endocrine therapy combined with chemotherapy are associated with an improvement in survival for patients with metastatic disease. Future research efforts directed at defining the molecular mechanisms of endocrine activity should facilitate clinical trials of newer and potentially more effective agents. All patients with metastatic breast cancer should be considered for at least one trial of endocrine therapy provided their metastatic disease is not rapidly progressive or life-threatening.
    Type of Medium: Electronic Resource
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  • 11
    ISSN: 1573-7217
    Keywords: breast cancer ; hepatitis B vaccination ; immune competence ; impaired immune response ; radiation therapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The response to hepatitis B (HBV) vaccination was studied in 32 breast cancer patients who were HBV antigen- and antibody-negative at the time of diagnosis. Ten of the patients included into the study received radical mastectomy without adjuvant therapy, 15 patients underwent breast-conserving surgery with subsequent irradiation with or without tamoxifen treatment, and 7 patients were treated by modified radical mastectomy plus adjuvant chemotherapy. Eight patients received the first dose of vaccine 3 months after irradiation therapy. Seven patients were first vaccinated 6 months following irradiation therapy. Seven healthy age-matched persons were vaccinated as controls. Antibody response in the patients was significantly delayed. Four weeks after the second vaccination 6 out of 7 controls showed a significant (〉10IU/ml) HBs antibody titer, while only 6 out of 32 patients responded. In addition, HBs antibody titers were also significantly lower after the second vaccination even in those patients treated with surgery alone, although they were first vaccinated 3 months after surgery and had no residual tumors. This difference disappeared after the second booster immunization, at which time the frequency of significant antibody titers and the levels of HBs antibody titers were comparable between patients and controls. As the population of patients undergoing treatment for breast cancer is increasing, additional studies are needed to determine optimal immunization regimens in this group of patients.
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 24 (1992), S. 11-16 
    ISSN: 1573-7217
    Keywords: breast cancer ; screening ; interval cancer ; overall survival
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The aim of the present study was to analyse the survival rate in a group of breast cancers detected in the intervals between screening examinations in relation to clinically detected cancers in a non-screened population. All interval and control cancers were recruited from a randomized controlled mammography screening trial in Stockholm. The overall survival up to eight years of observation was higher in 191 patients with interval cancers than in 142 control cancers (p=0.01). There were no significant differences between the two groups with regard to tumor size, stage distribution, or mean age, though the interval group did have a larger proportion of younger women. The similarity was confirmed by multiple regression analysis. The overall survival stage by stage was consistently higher in interval cancers. The survival rate in the true interval cancers was similar to that for those found in retrospect to have been detectable or traceable at the time of screening. No correlation was found between the length of the interval and the survival of patients with interval cancers. These results contradict the hypothesis that a high growth rate is associated with a poorer prognosis and that interval cancers are a more aggressive form of breast neoplasia.
    Type of Medium: Electronic Resource
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  • 13
    ISSN: 1573-7217
    Keywords: aminoglutethimide ; aromatase inhibition ; breast cancer ; 4-hydroxyandrostenedione ; oestrogen ; oestrone sulphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The clinical and biochemical effects of combined treatment with the two aromatase inhibitors aminoglutethimide and 4-hydroxyandrostenedione were evaluated in 10 patients suffering from advanced breast cancer. All patients had become resistant to treatment with one of the drugs before having combined treatment. Seven patients progressing on 4-hydroxyandrostenedione who had aminoglutethimide added to their treatment and achieved a further suppression of plasma oestradiol by a mean of 40.0% (p〈0.05). Plasma oestrone was suppressed by a mean of 40.6% (p〈0.025) and plasma oestrone sulphate was suppressed by a mean of 63.6% (p〈0.025). Two of the patients, neither of whom had responded to 4-hydroxyandrostenedione alone, experienced objective tumour regression when aminoglutethimide was given in concert. Three patients progressing on aminoglutethimide who had 4-hydroxyandrostenedione added showed no further suppression of their plasma oestrogen levels, and no tumour regression was observed. These findings suggest a dose-response relationship between plasma oestrogen suppression at low postmenopausal levels and objective tumour response in breast cancer.
    Type of Medium: Electronic Resource
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 24 (1992), S. 75-79 
    ISSN: 1573-7217
    Keywords: breast cancer ; lactic acidosis ; metabolic complication ; oncologic emergency ; paraneoplastic syndrome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case is presented of a patient with longstanding metastatic breast cancer whose condition suddenly deteriorated due to hypercalcemia and severe lactic acidosis which rapidly proved fatal. Postmortem examination showed no explanation for the lactic acidosis other than extensive metastatic disease. A review of the rare syndrome of malignancy-induced lactic acidosis is presented with particular emphasis on the 5 other cases reported in association with metastatic breast cancer. Theories of pathogenesis and management controversies are discussed.
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  • 15
    ISSN: 1573-7217
    Keywords: flow cytometry ; DNA ploidy ; S-phase fraction ; estrogen receptor ; breast cancer ; prognosis ; stage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The prospective prognostic significance of flow cytometry derived DNA-ploidy status, the level of the S-phase fraction (SPF), estrogen receptor (ER) content, and combinations of these factors, was evaluated with respect to overall survival (OS) in a series of 516 breast cancer patients who were without signs of residual or distant disease after primary completed treatment. The median duration of survival follow-up time was ten years (range, 95–148 months) for surviving patients. Of the single factors, ER was the only significant predictor among node-negative patients; the ten-year OS rate was 71% in cases with ER-rich tumors vs. 62% for ER-poor tumors (p=0.03). Where tumors were both non-diploid and ER-poor, the ten-year OS rate was 58%, as compared to 75% for the remaining node-negative patients (p=0.003), who constituted a low-risk group whose survival was comparable with that in the age-matched normal population. Among patients with 1–3 positive nodes, the ten-year OS rate was 65% in patients whose tumors had an SPF 〈7.3% vs. 50% if the SPF was ≥7.3% (p=0.01), and 58% in cases with ER-rich tumors vs. 45% where the tumors were ER-poor (p=0.02). In a multivariate analysis, apart from age and menopausal status the combination of ploidy status and ER content was the significant (p=0.002) predictor of OS in node-negative patients. Thus, combining ploidy and ER status, both of which are variables easily determined, enabled the selection of a subgroup of patients at high risk of relapse and reduced survival whose prognosis should be improved by effective adjuvant systemic treatment, whereas the remaining low risk N0 patients can not be expected to derive any survival benefit from adjuvant therapy since their predicted survival is already on a par with that of the general population.
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  • 16
    ISSN: 1573-7217
    Keywords: cathepsin-D ; proliferative activity ; breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Mitogenic properties have been demonstratedin vitro for the lysosomal acidic protease cathepsin-D (cath-D). We investigated possible relationships between cath-D cytosol cell content and tumor proliferative activity in a series of 129 operable breast cancer patients. For total cytosol cath-D evaluation, a solid phase two-site immunoradiometric assay was utilized on tumor cell cytosol obtained for hormone receptor assay (DCC method). The percentage of S-phase cells was analyzed by 3H-thymidine autoradiographic assay. Median 3H-thymidine Labeling Index (3H-Tdr-LI) of the series was 2.7%; median cath-D content resulted 57 pmol/mg of protein cytosol and was significantly higher in node-positive with respect to the node-negative subgroup (p〈0.03). When classified in low, intermediate or high tumor cath-D content and slow or fast proliferative activity (cut-off: median values of the series), no significant agreement was found between the two variables. Statistical analysis, however, showed that a significant inverse correlation existed in node positive tumors between cath-D and 3H-Tdr-LI values which was even more evident in N-positive high estrogen receptor-positive (ER+) cases (coefficient of correlation = −0.6828; p=0.0001). Cytosol cath-D content cannot be generally proposed as a direct marker of proliferative activity for operable breast cancer.
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  • 17
    ISSN: 1573-7217
    Keywords: breast cancer ; in situ hybridization ; interphase cytogenetics ; paraffin-embedded sections ; multistep carcinogenesis ; tumor cytogenetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Fluorescentin situ hybridization techniques have provided an important tool for interphase cytogenetic studies of human neoplasms. However, these techniques are difficult to use on formalin-fixed archival tissue sections. We describe here a non-fluorescent, non-isotopicin situ hybridization (ISH) approach that is easily applicable to paraffin-embedded breast tissue sections. The technical steps that must be monitored and individualized to optimize signal generation and detection are discussed. This ISH technique has several advantages over fluorescent detection methods. The signal obtained can be viewed using an ordinary light microscope and does not fade with time. More importantly, the signal is observed and analyzed in the context of tissue morphology. The technique permits detection of numerical chromosomal abnormalities not only in malignant but also in apparently normal and potentially premalignant mammary tissue. This may allow identification of focal genetic abnormalities as well as field-defects and enable analysis of their evolution during the multistep transformation to mammary neoplasm. This technique is also suitable for analysis of tumor heterogeneity and the correlation of numerical chromosomal aberrations with histologic, immunocytochemical, and clinical features of breast tumors.
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  • 18
    ISSN: 1573-7217
    Keywords: breast cancer ; cell lines ; cytosols ; differentiation ; placental isoferritin ; proliferation ; prognostic factors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Placental isoferritin (PLF), an acidic isoform of ferritin, and its unique superheavy chain p43 have been recently described to be synthesized by breast cancer cell lines but not by normal breast epithelial cells. Since previous reports have demonstrated a correlation between the content of ‘normal’ ferritin in breast cancer tissue, degree of differentiation, and prognosis, we have tried to evaluate the correlation of p43 in the cytosol of 122 breast cancer samples with commonly applied prognostic factors and features of proliferation and differentiation. In parallel, we investigated the correlation of p43 expression in MCF-7 and T47-D breast cancer cell lines during proliferation induced by estradiol plus fetal calf serum (assessed by3H-thymidine incorporation), compared to p43 expression in stationary non-stimulated cell cultures. The levels of p43 in breast cancer cytosols correlated significantly negatively with tumor size (p=0.0001), histologic grading (p=0.0038), nuclear pleomorphism (p=0.0019), rate of mitosis (p=0.0002), and lymphocytic reaction (p=0.0001), and significantly directly with the estrogen receptor status (p=0.0009). Although patients with a higher p43 content showed a trend for a better outcome (median follow-up: 61.4 months), an independent influence of the cytosolic p43 content on survival could not be confirmed by a multivariate Cox model. In accordance with the observed negative correlation of features of differentiation vs. p43 expression, induction of proliferation by estradiol plus FCS added to serum-free tissue culture medium correlated with a decrease of p43 synthesis in both cell lines. Expression of p43 in estrogen and FCS-absent media revealed also a decrease in relation to a low spontaneous proliferation. However, the drop of p43 synthesis was significantly stronger in cell lines with estrogen-stimulated proliferation. Ourin vitro and cytosol results confirm recent clinical observations describing an inverse correlation of p43 synthesis with the degree of proliferation and differentiation in breast cancer. However, the pathologic mechanisms leading to this phenomenon as well as the negative correlation with lymphocytic infiltration are still unclear and need to be further elucidated.
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  • 19
    ISSN: 1573-7217
    Keywords: breast cancer ; prognostic factors ; Cox regression ; all-subset regression ; accelerated failure time models
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Clinical studies usually employ Cox step-wise regression for multivariate investigations of prognostic factors. However, commercial packages now allow the consideration of accelerated failure time models (exponential, Weibull, log logistic, and log normal), if the underlying Cox assumption of proportional hazards is inappropriate. All-subset regressions are feasible for all these models. We studied a group of 378 node positive primary breast cancer patients accrued at the Henrietta Banting Breast Centre of Women's College Hospital, University of Toronto, between January 1, 1977, and December 31, 1986. 85% of these patients had complete prognostic factor data for multivariate analysis, and 96% of the patients were followed to 1990. There was evidence of marked departures from the proportional hazards assumption with two prognostic factors, number of positive nodes and adjuvant systemic therapy. The data strongly supported the log normal model. The all-subset regressions indicated that three models were similarly good. The variables 1) number of positive nodes, 2) tumour size, and 3) adjuvant systemic therapy were included in all three models along with one of three biochemical receptor variables 1) ER, 2) combined receptor (ER- PgR-; ER+ PgR-; ER- PgR+; ER+ PgR+; or 3) PgR. Better multivariate modeling was achieved by using quantitative prognostic factors, a check for appropriate underlying model-type, and all-subset variable selection. All-subset regressions should be considered for routine use with the many new prognostic factors currently under evaluation; it is very possible that there may not be a single model that is substantially better than others with the same number of variables.
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  • 20
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 23 (1992), S. 29-41 
    ISSN: 1573-7217
    Keywords: animal models ; breast cancer ; contraceptive steroids ; dogs ; humans ; mammary tumorigenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The safety of synthetic steroid hormones to be used for contraception in the human female is tested in rats, beagle dogs, and (once marketing starts) in monkeys. Because early studies did not show a mammary tumor stimulating effect in the human, in contrast to findings in the dog, many objections have been raised to the use of the dog for these toxicity studies. It has been claimed that the dog is unique in its sensitivity to the mammary tumor promoting effect of progestins and that this tumorigenic effect results from progestin-induced growth hormone (GH) induction. A thorough review of the literature does not support these claims. Tumor stimulatory effects of progesterone or synthetic progestins can be observed under some conditions in rodents as well as in cats and monkeys. In addition, recent evidence suggests a role for progesterone in mammary tumorigenesis in the human, and contraceptive steroids may also not be completely without risk. While the suggested role for GH in dog mammary tumorigenesis is far from proven, such a role cannot be excluded in the other species. Whether tumor stimulatory effects of sex steroids are based upon induction of proliferation in target cells or upon genotoxic effects or both is not yet certain.
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  • 21
    ISSN: 1573-7217
    Keywords: breast cancer ; breast fluid ; milk proteins ; prolactin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Breast secretions can be classified into two types according to their major protein components. Type I fluids contain Zn-α2-glycoprotein, apolipoprotein D, and gross cystic disease fluid protein-15, while Type II fluids are characterized by the presence of lactoferrin, lysozyme, and α-lactalbumin. In this study, the polypeptide composition of breast secretions from 719 nonlactating women was evaluated by using polyacrylamide gel electrophoresis. The required amount for the analysis (1 µl) was obtained from 50% of control women and from 75% of women with mammary disease. There were more secretors in premenopausal than in postmenopausal women, as well as in parous than in nulliparous women. Evaluation of factors affecting protein composition of breast secretions revealed that Type II fluids were found in the majority of women who had given birth in the last four years and in a high proportion of oral contraceptive users. After excluding both of these groups, Type II fluids were detected in 47% of patients with breast cancer, but only in 8% of control women and in 16% of women with benign breast diseases. Taken together, these results suggest that protein analysis of breast secretions could be an useful tool for the study of breast pathologies.
    Type of Medium: Electronic Resource
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  • 22
    ISSN: 1573-7217
    Keywords: breast cancer ; cytogenetics ; estrogen receptor ; genetic evolution ; ploidy ; progesterone receptor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The expression of estrogen (ER) and progesterone (PR) receptors was assayed by steroid binding in a series of 95 malignant breast tumors, for which the analysis of chromosome aberrations was performed and allowed the reconstruction of their chromosomal evolution. It was shown that breast tumors undergo a progressive loss of chromosomes, with occasionally one and rarely two endoreduplications. Chromosome losses were often the consequence of rearrangements, and the rate of rearranged chromosomes, which increases progressively, appeared as a possible indicator of tumor progression. The distribution of ER and PR values in the sample of 95 tumors was compared to that of a larger control series of consecutive cases: 598 for ER and 460 for PR. The similarities of the distributions indicated that the sample of 95 tumors was representative of the general population of breast cancers. The levels of ER and PR expression were very strongly and negatively correlated to the rate of rearranged chromosomes, but not to the modal number of chromosomes. However, when tumors having either undergone endoreduplication or not (〉50 or 〈51 chromosomes, respectively) were considered separately, a significant correlation between ER and PR expression and chromosome number was found within each group. Finally, breast cancers were subdivided into 4 stages of cytogenetic evolution, from the least to the most evolved: stage 1: ≤50 chromosomes, 〈25% rearranged chromosomes; stage 2: 〉50 chromosomes, 〈25% rearranged chromosomes; stage 3: ≤50 chromosomes, 〉25% rearranged chromosomes; stage 4: 〉50 chromsomes, 〉25% rearranged chromosomes. The rate of negative or low ER values (〈500 fmol/g tissue) was 10% in stage 1; 16% in stage 2; 45% in stage 3; 82% in stage 4. The corresponding rates for negative or low PR values (〈500 fmol/g tissue) were 17%; 28%; 60%; and 91%. These data illuminate the probable role of genetic evolution in determining the variations of biological prognostic parameters of breast cancer, such as steroid hormone receptors.
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  • 23
    ISSN: 1573-7217
    Keywords: breast cancer ; epidermal growth factor receptors ; steroid receptors ; quality control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This study investigates the effect of freezing and storage of tissue and subcellular fractions on the measurement of epidermal growth factor receptors (EGF-r); compares competition binding and single saturating dose assays (SSD) for quantitating EGF-r levels; investigates several tissues as potential quality control; and examines the relationship between EGF-r and hormone receptor expression in human breast cancers. Mouse and calf uterine cell membranes were preferred sources of quality control tissue with similar levels of high affinity EGF-r to human breast cancer tissue (〈150–200 fmol/mg membrane protein). Studies using pooled mouse uterine tissues indicated a loss of 40% in EGF-r activity following a single −20°C freeze/thaw cycle, while a breast cancer tissue showed a 75% loss, independent of storage temperature (liquid nitrogen, −70°C, −20°C). A single freeze/thaw cycle of mouse uterine broken cell pellets (nuclei plus membrane fraction) again indicated a loss of EGF-r irrespective of storage temperature (43% loss at −70°C, 52% loss at −20°C). In most cases irrespective of the tissue type or tissue fraction being stored, the length of storage had little impact on the extent of the loss in activity. A second freeze/thaw cycle of intact tissue, or freezing of broken cell pellets from a previously-frozen tissue, led to a further major or total loss of the remaining EGF-r. Overall these results are commensurate with the published effects of freezing and storage on estrogen receptor measurement. In addition, our studies suggest that the most suitable procedure for assaying frozen breast cancer specimens for EGF-r levels in conjunction with steroid receptor quantitation is to prepare and assay both cytosol and membrane fractions for their respective receptor content without further storage. A concordance of 86% was found in 44 breast cancers assayed for EGF-r by saturation analysis and SSD. Statistically significant inverse relationships were found between EGF-r and estrogen and progesterone receptor levels in a study of approximately 350 breast cancer patients. No association was found with tumor stage or diameter, axillary node involvement, or patient age.
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  • 24
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    Breast cancer research and treatment 22 (1992), S. 187-191 
    ISSN: 1573-7217
    Keywords: breast cancer ; data representation ; multivariate variable-selection ; prognostic factors ; validation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This special issue of Breast Cancer Research and Treatment addresses the topic of how to evaluate new prognostic factors for breast cancer, and how the information provided by these new factors might be integrated with traditional factors to make better treatment decisions for these patients. Although the focus is on breast cancer, the techniques described are equally applicable to any situation involving survival or failure over time.
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  • 25
    ISSN: 1573-7217
    Keywords: breast cancer ; conservation treatment ; local excision ; mastectomy ; radiotherapy ; rehabilitation ; surgery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Recent data suggest that prognosis is similar for women with primary breast cancer whether they receive modified radical mastectomy (MRM) or local excision and axillary dissection with radiation (XRT). The effects of either of these treatments on arm mobility, pain, or edema have not been compared. To assess the impact of MRM or XRT on mobility, pain, or edema, we evaluated patients treated in a prospective randomized trial designed to assess prognosis following MRM or XRT. All were provided a standardized physical therapy program including arm mobilization, shoulder strengthening, prevention and treatment of upper extremity edema, and education about arm function. Patients were evaluated for chest wall pain, arm motion, muscle strength, and edema as determined by circumferential measurements at the wrist, forearm, and arm. Evaluations were performed preoperatively and at yearly anniversaries of their surgery. Women receiving XRT had more chest wall tenderness at 1 and 2 years after surgery than those receiving MRM (p2〈0.0001 and p2=0.0007 respectively). Those receiving MRM were slower to reach their preoperative range of motion (ROM) (p2=0.043). Incidence of muscle weakness was similar in both groups. The few patients with local recurrence of tumor had more upper extremity edema than those who did not recur (p2=0.085) at 1 year and (p2=0.02) at 2 years. In patients who did not develop local recurrence, those who had received XRT had greater but nonsignificant increases in upper extremity circumferential measures compared with those receiving MRM at any anniversary evaluation. Patients receiving MRM and XRT are likely to have some differences in functional outcome. These differences may be important to individuals and be significant in helping them choose between MRM and XRT based upon individual functional needs.
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  • 26
    ISSN: 1573-7217
    Keywords: breast cancer ; family history ; reproductive history ; diet ; obesity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To study the effects of family history and reproductive, anthropometric, and dietary factors on the risk of breast cancer among low risk populations, we conducted a hospital-based case-control study involving 908 patients with breast cancer and their matched controls, in Japan. A positive family history of breast cancer significantly increased the risk of breast cancer (odds ratio = 1.52, 95% confidence interval: 1.14–2.03). The risk further increased with increasing number of family members affected. Obesity, single marital status, fewer births, a late childbirth, and less consumption of green-yellow vegetables and dairy products were also associated with an increased risk of breast cancer. These associations were independent in multivariate analyses. There was no increase in risk associated with consumption of high fat foods. When analyzed by menopausal status, the association with family history of breast cancer, especially in the first degree of relatives, was more evident for premenopausal breast cancer. The associations with obesity and lower consumption of dairy products were more pronounced for postmenopausal breast cancer, while those with lower parity and single marital status were stronger for premenopausal breast cancer.
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  • 27
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    Breast cancer research and treatment 22 (1992), S. 129-132 
    ISSN: 1573-7217
    Keywords: tamoxifen ; breast cancer ; body weight
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Changes in body weight have been studied in 92 consecutive patients with primary breast cancer from the time of initial diagnosis and treatment. Sixty patients receiving tamoxifen were compared with 32 controls receiving no hormone treatment. Weight gain was seen in both groups, but was greater in the group receiving tamoxifen. Premenopausal women receiving tamoxifen had greater weight gain than postmenopausal women on tamoxifen therapy.
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  • 28
    ISSN: 1573-7217
    Keywords: aminoglutethimide ; breast cancer ; endocrine therapy ; medroxyprogesterone acetate ; tamoxifen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In order to evaluate the efficacy of two different sequences of second and third line hormonotherapy in advanced post-menopausal breast cancer, 257 women aged 36–91 years (mean age: 63.6 years) who had become resistant to tamoxifen (TAM), entered into a multicenter randomized trial comparing two different regimens: 1) Aminoglutethimide (Ag) 500 mg/day with hydrocortisone supplementation from 30 to 60 mg/day; and 2) oral medroxyprogesterone acetate (MPA) 500 mg twice a day. 250 patients were evaluated following second line hormone therapy and, after cross-over, 128 following third line hormonotherapy. No significant difference was observed, during either second or third line therapies, for toxicity, survival, or response rate; however, in both second and third line therapies the median time to progression was significantly longer with Ag therapy.
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  • 29
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    Breast cancer research and treatment 22 (1992), S. 59-67 
    ISSN: 1573-7217
    Keywords: benign breast disease ; breast cancer ; IGF receptors ; insulin-like growth factors ; prognosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The first step of the action of IGF1 and IGF2 (IGFs) is their binding to membrane receptors. IGF binding sites have been characterized by competitive binding and cross-linking techniques in human breast cancer cell lines as well as in human breast cancers and in human benign breast diseases. IGF2 is a good competitor of125I-IGF1 binding to IGF1-R; insulin competes but with a potency 1/100 lower than the IGF1 potency. Chemical cross-linking experiments revealed that the apparent molecular weight of the IGF1-binding sites is 130,000. Alpha IR-3, a murine monoclonal antibody against the IGF1-R, blocks IGF1-binding to this receptor. This antibody inhibits the IGF1-stimulated growth of breast cancer cells. Therefore, the IGF1 specific binding sites correspond to the previously described type 1 IGF receptors (IGF1-R) in normal tissues. Cross-linking experiments with labeled IGF2 resulted in a major band of apparent Mr 260,000–270,000 that was inhibited by unlabeled IGF2 but not by insulin, and corresponds to the type 2 IGF receptor; a second band of apparent Mr 130,000 was inhibited by excess IGFs and insulin (Type I receptor). The alpha-IR3 inhibition of the IGF2 mitogenic activity suggest that IGF1-R partially mediates the growth effect of IGF2 in these cells. We and others have demonstrated that most breast cancer cell lines contain IGF1-R. This is also the case in breast cancer biopsies in which histo-autoradiographic analyses allowed the localization of IGF1-R on the epithelial component. IGF1-R concentrations were positively correlated to estradiol and progesterone receptor concentrations. In our experience, the presence of IGF1-R is associated with a better prognosis. Finally, IGF1-R are found less frequently and at lower concentrations in benign breast diseases. These results suggest that IGF1-R could be a marker of the proliferative epithelial component within the tumor.
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  • 30
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    Breast cancer research and treatment 22 (1992), S. 241-250 
    ISSN: 1573-7217
    Keywords: breast cancer ; clinical trials ; Cox regression model ; generalized additive model ; non-linear prognostic factor modelling ; proportional hazards ; regression splines ; smoothing splines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The proportional hazards model is frequently used in analyzing the results of clinical trials, when it is often the case that the outcomes are right-censored. This model allows one to measure treatment effects and simultaneously identify and adjust for prognostic factors that might influence the outcome. In this paper, we outline a class of semiparametric models that allows one to model prognostic factors nonlinearly, and have the data suggest the form of their effect. The methods are illustrated in an analysis of data from a breast cancer clinical trial.
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  • 31
    ISSN: 1573-7217
    Keywords: adriamycin ; breast cancer ; chemosensitivity assay ; lonidamine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Lonidamine is a new potential chemotherapeutic agent, relatively non-toxic, that can positively modulate the efficacy of several antineoplastic drugs. We evaluated the response of two established human breast cancer cell lines (MCF-7 and BRC-230) and of 20 primary breast cancer cell lines to lonidamine, either alone or in combination with adriamycin, the drug most widely used in the management of breast cancer. Different schedules were tested by varying either concentration of the drugs (LND: 10–150µg/ml; ADM: 0.10–0.15µg/ml), or time of exposure (1–96 hours), or sequence of administration (ADM → LND; LND → ADM; ADM + LND). Our results indicate slight sensitivity of the cell lines to lonidamine when used alone, whereas an increase of efficacy was noted when lonidamine was added for at least 24 hours after a 4 hour exposure to adriamycin. Such efficacy was significantly greater than that expected from an additive effect between the two drugs. We conclude that lonidamine, when given according to an appropriate schedule, enhances,in vitro, the efficacy of adriamycin. A correct employment of lonidamine in the management of breast cancer might therefore potentiate the therapeutic effect of adriamycin.
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  • 32
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    Breast cancer research and treatment 24 (1992), S. 97-102 
    ISSN: 1573-7217
    Keywords: c-erbB-2 protein ; breast cancer ; tumor marker ; enzyme immunoassay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The c-erbB-2 protein was measured in sera of patients with breast cancer or benign breast diseases to study the significance of this protein as a tumor marker. The mean value and positive rate for this protein (assuming 20 U/ml as the cut-off value) were 11.8 U/ml (0%) in benign breast disease (n=30), 11.8 U/ml (3.1%) in stage I/II primary breast cancer (n=64), 38.2 U/ml (29.4%) in stage III/IV primary breast cancer (n=17), 17.9 U/ml (33.3%) in locally recurrent breast cancer (n=12), 298.4 U/ml (51.0%) in recurrent breast cancer with distant metastases (n=51), and 12.9 U/ml (0%) in those with no evidence of recurrence (n=57). Thus, the serum c-erbB-2 protein level was significantly higher in the distant metastatic group. In patients with distant metastases, there was a close association between expression of c-erbB-2 protein in the primary tumor and the serum c-erbB-2 protein level. On the basis of these results, serum c-erbB-2 protein was thought to be useful as a tumor marker for postoperative monitoring of breast cancer, especially in patients positive for expression of this protein in primary cancer tissue.
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  • 33
    ISSN: 1573-7217
    Keywords: androgens ; breast cancer ; medroxyprogesterone acetate ; 50:50 poly[DL-lactide-co-glycolide] microspheres
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Since our previous findings had indicated that the androgenic steroid medroxyprogesterone acetate (MPA) exerts potent inhibitory effects on 7,12-dimethylbenz(a)anthracene (DMBA)-induced tumor growth, we have studied the effect of low doses of MPA released from Depo-Provera and from 50:50 poly[DL-lactide-co-glycolide] microspheres in the same DMBA-induced tumor model. The present data show that single subcutaneous injection of a 4-month controlled-release formulation of biodegradable 50:50 poly[DL-lactide-co-glycolide] microspheres containing 10 mg of MPA giving serum levels of 3.14±0.32 ng/ml (8.12±0.83 nM) MPA causes a maximal or near-maximal 60% inhibition of tumor growth measured 56 days later. Such data suggest that controlled-release formulations giving constant and low blood levels of MPA could be used for the treatment of breast cancer in women. Such a low concentration of MPA should avoid the side effects observed with the high doses of the compound.
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  • 34
    ISSN: 1573-7217
    Keywords: breast cancer ; LH-RH binding sites ; targeted chemotherapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The binding characteristics of several cytotoxic analogs of luteinizing hormone-releasing hormone (LH-RH) developed in our laboratory were examined in membranes from human breast cancer and estrogen independent MXT mammary cancer. Specific binding of [125I]D-Trp6-LH-RH and the cytotoxic LH-RH analog [125I]T-98 ([D-Lys6]LH-RH coupled to glutaryl-2-(hydroxymethyl)anthraquinone) (HMAQG) was demonstrated in membrane preparations from human breast and MXT mammary tumor cells. Ligand binding of T-98 was specific, saturable, and dependent on temperature, time, and plasma membrane concentration. Analysis of the binding data showed that in human breast cancer, interaction of [125I]T-98 was consistent with the presence of two classes of LH-RH receptors, one class showing high affinity and low capacity, and the other class showing low affinity and high capacity binding. In membranes from MXT mammary cancer, T-98 bound to one class of saturable, specific, noncooperative binding sites with high affinity and low capacity. The rates of association and dissociation for [125I]T-98 were calculated to be 4.757×108 M−1 min−1 and 0.016 min−1 (t1/2=38.7) in membranes from MXT mammary cancer. In human breast cancer, association rate constants (K1a and K1b) were 2.3×106 M−1 min−1 for binding to high affinity and 1.8×104 M−1 min−1 for binding to low affinity binding sites. Dissociation rate constants were K−1a=0.0801 min−1 (t1/2a=63.4 min) and K−1b=0.0467 min−1 (t1/2b=23.5 min), respectively. [125I]T-98 was not displaced by either unlabeled somatostatin or epidermal growth factor, but was displaced completely by unlabeled T-98 or [D-Trp6]LH-RH. The analysis of displacement curves of [D-Trp6]LH-RH by cytotoxic agonists and antagonists of LH-RH synthesized in our laboratory showed that T-121, AJ-11, T-120, T-133, and T-98 were the most potent in displacing [125I]D-Trp6-LH-RH from breast and MXT cancer membranes. Binding kinetics and analyses of displacement curves of [125I]D-Trp6-LH-RH and [125I]T-98 in membranes of human breast cancer and estrogen independent MXT mouse mammary cancer suggest that binding of the cytotoxic analog T-98 to the LH-RH receptor proceeds reversibly like that of its congeners without cytotoxic radicals. Our findings may provide a stimulus for further studies with LH-RH analogs carrying cytotoxic radicals. Such analogs could be targeted to breast cancer and other cancers that have membrane receptors for LH-RH. Because the antitumor action may be exerted to a greater degree at more selective sites that have the cell membrane receptors, the peripheral toxicity could be reduced.
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  • 35
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    Breast cancer research and treatment 21 (1992), S. 27-34 
    ISSN: 1573-7217
    Keywords: breast cancer ; chemotherapy ; combination ; dose intensification ; new drugs ; outpatient treatment ; quality of life ; single agents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The treatment of advanced breast cancer has undergone relatively little change in the past decade. Reasons for such a static situation are the sobering realization that even effective chemotherapeutic regimens have had a minor impact on survival, and the paucity of new effective agents that have been introduced since initial combination treatments. Based in part on this lack of progress, in recent yearsdose-intensification in search of a curative strategy has been widely adopted. Its role remains to be defined, but ultimately it is likely to be relegated to situations where tumor burdens have been effectively reduced. This reduction in burden may not currently be feasible in many advanced presentations. Outpatient efforts will therefore focus on the following: 1) employing single agents optimally (e.g. infusion 5-fluorouracil), 2) using regimens which integrate new drugs with activity (e.g. taxol), and 3) testing measures which may improve the quality of life (e.g. bisphosphonates in the presence of bone metastases). Although one cannot approach the treatment of advanced breast cancer with the (misplaced) optimism of two decades ago, the expanded armamentarium currently available should lead to a more rational application of chemotherapy. Treatments will increasingly be based on the biology of the cancer, and on the therapeutic index and action of the drugs.
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  • 36
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    Breast cancer research and treatment 21 (1992), S. 95-100 
    ISSN: 1573-7217
    Keywords: breast cancer ; HPV ; in situ hybridization ; PCR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Histological sections from paraffin-embedded breast carcinoma and axillary lymph nodes were examined for the presence of human papillomaviruses by two different techniques: the polymerase chain reaction (PCR) and thein situ hybridization with biotin-labelled probes. By PCR we detected HPV 16 DNA sequences in 29.4% of breast tumours and in some metastatic lymph nodes, though we were unable to identify any HPV DNA sequences byin situ hybridization. These results suggest that HPV's could play a role in the genesis of breast neoplasia.
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  • 37
    ISSN: 1573-7217
    Keywords: breast cancer ; chemotherapy ; doxorubicin ; mitoxantrone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Weekly low dose mitoxantrone (3 mg/m2) plus doxorubicin (8 mg/m2) was administered as second-line chemotherapy to 33 patients with advanced breast cancer. Four out of 28 evaluable patients (14%) obtained a partial response with a median duration of 34 weeks (range 18–67+ weeks), while 8 patients (29%) showed stable disease with a median duration of 28 weeks (range 11+–60 weeks). Gastrointestinal toxicity and alopecia were mild. Grade II and III leukopenia occurred in 63% of the courses without serious infectious disease. Four patients experienced an asymptomatic drop of 16–20% in the left ventricular ejection fraction (LVEF) after relatively low cumulative doses of each drug, and one patient with a history of pericarditis carcinomatosa and mediastinal irradiation developed a heart failure. In conclusion, this second-line combination treatment had moderate activity in breast cancer and caused only few subjective side effects, especially with respect to gastrointestinal symptoms.
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  • 38
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    Breast cancer research and treatment 21 (1992), S. 155-164 
    ISSN: 1573-7217
    Keywords: breast cancer ; clinical trials ; ductal carcinoma in-situ ; lobular carcinoma in-situ ; tumor biology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Non-invasive breast cancer is comprised of two distinct entities: lobular carcinoma in-situ (LCIS) and ductal carcinoma in-situ (DCIS). The natural history of each clinical entity is described and a biologic interpretation of the available data is offered. Lobular carcinoma in-situ is considered only a risk marker rather than a precursor for the subsequent development of invasive cancer, so that once the diagnosis is established, further operative intervention is unnecessary and serial follow-up alone is recommended. The treatment of ductal carcinoma in-situ must take into account that breast-preserving therapy is now considered optimal treatment of invasive cancer of the breast, the disease we are trying to prevent. The pitfalls of recommending treatment based on retrospective data is emphasized and the need to support clinical trials designed to determine the optimal therapeutic management of intraductal carcinoma is affirmed.
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  • 39
    ISSN: 1573-7217
    Keywords: breast cancer ; human milk fat globule antibodies ; immunohistochemistry ; prognosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The status of axillary lymph nodes in patients with breast cancer is important prognostically but does not identify all patients who will have long or short survival. To determine if the immunohistochemical reaction of tumor cells to human milk fat globule (HMFG) antibodies will define prognosis more specifically, we examined patients with node-negative disease and patients with more than three positive nodes, the extremes of the prognostic spectrum. In both node-negative and node-positive groups, patients who relapsed were matched by age at diagnosis, tumor size, histologic type, and receptor status, with patients who remained disease-free for a minimum of 48 months. Patients with poor survival had a higher proportion of poorly differentiated cancers. The ability to generate antigens recognized by HMFG antibodies was decreased in patients with recurrent disease, but this was significant only in patients with node-positive tumors. Tumors of patients who remained disease-free were more likely to have a pattern of membrane staining, while cytoplasmic staining was more frequent in those who relapsed. The results suggest that immunohistologic response to HMFG antibodies may assist in identifying cancers with poor prognosis, supplementing the prediction derived from node status.
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  • 40
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    Breast cancer research and treatment 22 (1992), S. 157-161 
    ISSN: 1573-7217
    Keywords: breast cancer ; estrogen ; MCF-7 cells ; regulation ; sulfotransferase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The importance of the steroid hormone microenvironment within cells is now recognised in studies on endocrine-related neoplasms such as breast cancer. This focuses attention on ezymes which control the intracellular levels of estradiol-17β (E2). One such enzyme, estrogen sulfotransferase, which converts E2 to inactive E2-3 sulfate, has now been shown to be regulated by estrogen in MCF-7 human mammary cancer cells. Hydroxysteroid sulfotransferase, which sulfurylates the adrenal-derived estrogen 5-androstene-3β,17β-diol, is also under estrogen control. Evidence is provided which shows that one function of these enzymes may involve elimination of estrogen from the cell following processing of the ligand-charged estrogen receptor (ER).
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  • 41
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    Breast cancer research and treatment 23 (1992), S. 71-76 
    ISSN: 1573-7217
    Keywords: breast cancer ; differentiation ; immunohistochemistry ; milk fat globule antibodies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Immunohistochemical studies of human breast cancers using human milk fat globule (HMFG) antibodies are divergent regarding the association with histologic differentiation. To clarify this association 392 tumors were assessed using two antibodies, HMFG-1 and HMFG-2. In half the tumors studied the tissue reaction to both antibodies was the same and in 63% the site of reaction was identical. Using both univariate and multivariate statistics, a highly significant association was recorded between membrane staining and well differentiated cancers and cytoplasmic staining and poor differentiation. Well differentiated tumors contained significantly more reactive cells. Complementing these findings was the association between age at diagnosis, tumor stage, and estrogen receptor status and differentiation. It is possible that immunohistochemical analysis with HMFG antibodies will provide better characterization of tumor differentiation than morphologic interpretation.
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  • 42
    ISSN: 1573-7217
    Keywords: neural networks ; breast cancer ; prognosis ; survival analysis ; Cox regression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Neural Network Analysis, a form of artificial intelligence, was successfully used to predict the clinical outcome of node-positive breast cancer patients. A Neural Network was trained to predict clinical outcome using prognostic information from 1008 patients. During training, the network received as input information tumor hormone receptor status, DNA index and S-phase determination by flow cytometry, tumor size, number of axillary lymph nodes involved with tumor, and age of the patient, as well as lengtl of clinical followup, relapse status, and time of relapse. The ability of the trained Network to determine relapse probability was then validated in a separate set of 960 patients. The Neural Network was as powerful as Cox Regression Modeling inidentifying breast cancer patients at high and low risk for relapse.
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  • 43
    ISSN: 1573-7217
    Keywords: breast cancer ; estrogen receptor ; prognosis ; prognostic factors ; pS2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary pS2 protein expression has been reported to have prognostic significance in human breast carcinomas and to correlate with estrogen receptor positivity, although these findings have not been confirmed by all investigators. pS2 positivity was compared to various clinical and histologic parameters in a retrospective study of 290 patients (median follow-up 7.2 years) and significantly correlated with tumor grade and estrogen receptor content (p=0.001 and p=0.0007, respectively). Significant associations between pS2 positivity and lymph node metastases, T stage, histologic tumor type, and patient age were not observed. Univariate and multivariate analyses (controlling for estrogen receptor content, T and N stage) of the patient population at large showed that pS2 positivity was not predictive of disease-free or overall survival. Univariate analysis of lymph node negative patients demonstrated that both pS2 and estrogen receptor positivity were significantly associated with a better outcome. Multivariate analysis of these patients, however, showed that only estrogen receptor data had independent prognostic significance. This study suggests that immunohistochemical analysis for pS2 protein expression will not contribute additional prognostic information if the estrogen receptor content is known.
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  • 44
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    Breast cancer research and treatment 21 (1992), S. 173-180 
    ISSN: 1573-7217
    Keywords: breast cancer ; site of first metastasis ; survival ; nodal status ; estrogen receptors ; progesterone receptors ; prognosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Survival from the detection of first metastasis (SAM) was analyzed in a single center series of 258 patients with advanced breast cancer. During the 15 year period covered by this study 230 patients died, 215 of their disease. The overall median SAM was 28 months. Univariate analysis of SAM stratified by first dominant site of metastasis, estrogen receptor status (ER), progesterone receptor status (PgR), tumor size, axillary lymph node status, patient age, menopausal status, and disease-free interval (DFI) showed the first dominant site of metastasis, ER, PgR, and axillary lymph node status to be significantly associated with SAM. Patients with visceral metastasis as first dominant site of metastasis had significantly shorter survival than those with either bone or soft tissue metastasis, median SAM 16 vs. 34 vs. 41 months respectively (P〈0.001). SAM also differed according to the steroid hormone receptor status of the primary tumor: median SAM 34 and 33 months for patients with ER-positive or patients with PgR-positive tumors against 14 months for patients with ER-negative or with PgR-negative tumors (P〈0.001). Patients with axillary lymph node involvement at primary disease had a shorter SAM than those without, median SAM 24 vs. 35 months (P=0.006). No association between SAM and either tumor size, patient age, menopausal status, or DFI could be observed. Multivariate analysis including first dominant site of metastasis, ER, PgR, and axillary lymph node status showed the first dominant site of metastasis, ER, and axillary lymph node status to be independently associated with SAM.
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  • 45
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    Breast cancer research and treatment 21 (1992), S. 3-13 
    ISSN: 1573-7217
    Keywords: breast cancer ; high-dose chemotherapy ; hormone therapy ; new therapy ; new drugs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Progress in the treatment of breast cancer developed along multiple directions of research during the last decade. The concept of dose-intensity was addressed through retrospective analyses and prospective randomized trials. It was confirmed that dose-intensity correlates with higher response rates, but the effect of dose-intensive treatments on survival still needs to be established. Several new cytotoxic drugs have appeared during the last several years. Taxol, navelbine, and anthrapyrazole CI-941 have been found to have major efficacy against breast cancer, with response rates exceeding 50%. Amonafide, lonidamine, and elliptinium analogs were also shown to be effective, although to a lesser degree. Antiestrogen analogs, new aromatase inhibitors, and LHRH analogs are recent developments that are changing the face of hormonal therapy. Monoclonal antibodies are being developed and evaluated for tumor imaging applications and as vehicles for specific antitumor agents (cytotoxics, radioisotopes, and toxins). Expanding knowledge about the basic biology of breast cancer has led to the identification of growth factors and their receptors, which may be exploited for therapeutic purposes in the not too distant future.
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  • 46
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    Breast cancer research and treatment 21 (1992), S. 211-216 
    ISSN: 1573-7217
    Keywords: breast fluids ; epithelial membrane antigen ; polymorphic epithelial mucin ; breast cancer ; witch's milks
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We have examined breast fluids from non-lactating women and male neonates for the expression of epithelial membrane antigen (EMA), also termed polymorphic epithelial mucin (PEM). All fluids exhibited significant amounts of EMA as demonstrated by immunoblot analyses and enzyme immunoassay. EMA was present in the breast fluids of both pre- and post-menopausal women, and these results suggest that nipple aspirates could provide an easily accessible source of antigen for assessing the value of EMA as a tumor marker both before and after various therapeutic modalities. The presence of EMA in the ‘witch's milks’ indicates that full maturation of the breast is not a prerequisite for antigen expression in breast tissue.
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  • 47
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    Breast cancer research and treatment 22 (1992), S. 285-293 
    ISSN: 1573-7217
    Keywords: artificial intelligence ; breast cancer ; neural networks ; prognostic factors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary It has been previously shown that Neural Networks can be trained to recognize individual breast cancer patients at high and low risk for recurrent disease and death. This paper expands on the initial investigation and shows that by coding time as one of the prognostic variables, a Neural Network can use censored survival data to predict patient outcome over time. In this demonstration a Neural Network was trained, tested, and validated using censored survival data from a group of 1373 patients with node-positive breast cancer. The Neural Network method predicted patient outcome as accurately as Cox Regression modeling. The final Neural Network model can be presented with a patient's prognostic information and make a series of predictions about probability of relapse at different times of follow-up, allowing one to draw survival probability curves for individual patients.
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  • 48
    ISSN: 1573-7217
    Keywords: amplification ; c-erb-B2 ; PCR ; fine-needle biopsies ; breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Aspiration of tumor cells by the fine-needle biopsy method yields only a small number of cells, which hampers conventional molecular analysis for the presence of multiple copies of oncogenes. We have therefore adopted the polymerase chain reaction (PCR) method to study semi-quantitatively the level of the c-erb-B2 gene in human breast tumor samples. Of 39 patients with mammary carcinoma, 7 (19%) contained multiple copies of c-erb-B2 genes, whereas only two samples failed to give informative data. Next the temporal appearance of multiple gene copies was examined in 20 patients with clinical stage IV disease. Tumor samples were obtained every second to third month from the same tumor lesion of each patient. None of the initial samples from each patient contained multiple copies of c-erb-B2. Of 16 patients that showed progressive clinical disease, 5 developed multiple gene copies, showing that the event occurs in clinical stage IV disease.
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  • 49
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    Clinical & experimental metastasis 10 (1992), S. 329-336 
    ISSN: 1573-7276
    Keywords: axillary metastases ; breast cancer ; metastatic spiral ; periodicity ; quantitation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: The clinical value of assessment of tumour load in the axilla in the treatment of breast cancer patients has stood the test of time. Much information is available on its extent and characteristic distribution but, in contrast, little is known of the biological factors that may control the timing of the metastatic phenomenon. There is recent circumstantial evidence that such factors may exist and this prompted the present detailed study of axillary metastases from a series of 437 consecutive cases of breast carcinoma. Evidence of such factors was found here also: the excess of micrometastases in cases coming to operation in the second half of the year was highly significant (P 〈 0.001) and is consistent with a synchronized start to the metastatic process. The total metastatic pattern in the material further indicated that the process may show periods of inactivity, i.e. periods when new colonies are not recruited. Mechanisms controlling this periodicity could theoretically be light-mediated, opening up new possibilities in the development of anti-metastatic treatment regimes.
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  • 50
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    Clinical & experimental metastasis 10 (1992), S. 121-124 
    ISSN: 1573-7276
    Keywords: breast cancer ; axillary nodes ; tumour area ; prognosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: The tumour-load in the axilla of breast cancer patients is classically measured from the number of tumour-bearing nodes present, which is then used to assess prognosis. This preliminary morphometric study on 73 cases of breast carcinoma for which standardized axillary dissection specimens were available shows that the total tumour load, measured from the sum of the tumour area (cm2) in hilar nodal sections, gives a redistribution of the patients; one that may provide better prognostic information in particular in women with a high tumour load. In those with four or more nodes involved the actual number is said to give little prognostic discrimination at 4 years post-operatively, as was demonstrated in this series. In contrast, using data from the same patients, the risk of death by this time increased steadily with increasing tumour area.
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  • 51
    ISSN: 1573-7276
    Keywords: breast cancer ; dietary fat ; nude mice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: The effects of inoculation site and dietary fat intake on the growth and metastasis of the MDA-MB-435 human breast cancer cell line were studied in athymic nude mice. The tumor cells, 1 × 106, were injected into either a right-sided thoracic or inguinal mammary fat pad (mfp), and 1 week later mice were randomly assigned to a high-fat (HF), 23% corn oil, or a low-fat (LF), 5% corn oil, diet. There were 30 mice in the HF, and 30 in the LF subgroups from each of the two inoculation site groups. The experiment was terminated 15 weeks after the tumor cell inoculations. Within the thoracic mfp-injected group, a HF diet reduced latency, increased growth rate at the primary site, and enhanced metastasis to regional lymph nodes, lungs, and intra-abdominal sites. For mice inoculated into an inguinal mfp, fat intake affected neither primary nor metastatic tumor development and growth; in both subgroups lung metastasis was significantly less than in the HF-fed, thoracic mfp-injected subgroup. The histological features of the lung metastases were consistent with a vascular mode of spread, whereas the extensive intra-abdominal lymph node involvement observed in mice with inguinal mfp tumors was in keeping with lymphatic-borne metastases.
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  • 52
    ISSN: 1573-7225
    Keywords: α-carotene ; α-tocopherol ; benign breast disease ; β-carotene ; breast cancer ; dietary intake ; γ-tocopherol ; lycopene ; serum ; United States
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: We investigated the relationship between serum levels of retinol, β-carotene, α-carotene, lycopene, α-tocopherol, and γ-tocopherol as well as intakes of retinol, carotene, and vitamin E and the risks of breast cancer and proliferative benign breast disease (BBD) in a case-control study of postmenopausal women in the Boston, MA (United States) area. Serum nutrient data were available for 377 women with newly diagnosed stage I or II breast cancer and 173 women with proliferative BBD. Controls were 403 women who were evaluated at the same institutions but did not require a breast biopsy or whose biopsy revealed nonproliferative BBD. We observed no significant associations between serum levels of these micronutrients and risk of proliferative BBD or breast cancer. The risk of breast cancer was decreased among women in the highest quintile of intake of vitamin E from food sources only (odds ratio [OR] for the highest quintile = 0.4,95 percent confidence interval [CI]=0.2–0.9; P, trend across quintiles = 0.02) but less so for total vitamin E intake including supplements (OR=0.7, CI=0.4–1.3; P, trend = 0.07).
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  • 53
    ISSN: 1573-7225
    Keywords: Attributable risk ; breast cancer ; Hawaii ; lung cancer ; prostate cancer ; saturated fat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: The dietary data from case-control studies of breast, prostate, and lung cancer in Hawaii revealed that saturated fat was a risk factor for these malignancies. The dietary intakes from the three studies were used to calculate the attributable risk (AR) due to saturated fat. For all ethnic groups combined, the ARs for the highest quartiles of intake were 14.9 percent for female breast cancer, 13.0 percent for prostate cancer, and 23.1 percent for male lung cancer. Our results suggested that a reduction of saturated fat to the lowest quartiles of intake could result in a 10 to 20 percent decrease in risk for these three cancers in Hawaii. We also examined the ethnic-specific risks associated with saturated fat consumption among the Japanese and the Caucasians in the three studies. The ARs for the highest quartiles of intake were notably higher among the Caucasians than the Japanese, primarily due to the difference in their dietary patterns. Although the calculated AR due to saturated fat was higher among the Caucasians than among the Japanese, all persons in the population would derive considerable benefit by reducing their intake of this nutrient.
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  • 54
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    Angewandte Makromolekulare Chemie 195 (1992), S. 139-150 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Eine Reihe makroporöser Glycidylmethacrylat-Ethylendimethacrylat-Copolymerer (GMA-co-EDMA) wurde durch Suspensionspolymerisation hergestellt; dabei wurden nach einer statistisch geplanten experimentellen Durchführung die Ethylendimethacrylatkonzentration und die Heizrate der Polymerisationstemperatur von 20 auf 70°C variiert. Die Porositätseigenschaften der hydrolysierten Copolymeren wurden mit Hilfe der Größenausschlußchromatographie unter Verwendung von Polystyrolstandards in Tetrahydrofuran charakterisiert. Das Porenvolumen, die spezifische Oberfläche und die Porengröße werden dabei durch die Konzentration des Vernetzungsmittels stärker beEinflußt als durch die Heizrate während der Polymerisation.
    Notes: A series of macroporous glycidyl methacrylate-ethylene dimethacrylate copolymers have been prepared by the suspension polymerization according to a statistical design of experimental approach in which concentration of ethylene dimethacrylate and time needed for raising the polymerization temperature from 20 to 70°C have been varied. The porous properties of hydrolyzed copolymers have been characterized by means of size exclusion chromatography using polystyrene standards in tetrahydrofuran. Pore volume, specific surface area, and pore size are affected by the crosslinking agent concentration rather than by the rate of temperature increase during the polymerization reaction.
    Additional Material: 2 Ill.
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  • 55
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    Angewandte Makromolekulare Chemie 195 (1992), S. 171-190 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Copolymers of AN were prepared with variable molecular masses and with variable contents of methylacrylate (ASME) and sodiumallylsulfonate (NaAS), acrylamide (AA), itaconic acid (IS), polyethyleneglycol acrylate (600) (PEGA), vinylacetate (VA), 2-hydroxyethyl acrylate, (HEE) or sodium acrylamido-2-methylpropanesulfonate (NaAMPS), respectively, by using a mathematical model for the calculation of the polymerization conditions needed. Precipitation studies by light scattering showed the predominant influence of NaAS and NaAMPS on the precipitation properties. Acrylonitrile homopolymers show a hard precipitation behaviour. The originating particles have a density of between 0.2 and 0.4 g/cm3. An increasing content of NaAS or NaAMPS leads for example beginning from 0.8 wt.-% NaAS in the monomer composition to a soft precipitation behaviour and to highly swollen particles possessing a density of less than 1 · 10-2 g/cm3. The molar mass and the ASME-content show no significant influence. For the acrylonitrile/acrylamide system already 0.5 wt.-% allylsulfonate is sufficient to get a soft precipitation behaviour with formation of highly swollen particles. All samples with the other cocomponents and without NaAS- or NaAMPS-comonomer show a hard precipitation behaviour with little swollen particles.
    Notes: Copolymere des Acrylnitrils (AN) mit variabler Molmasse bzw. mit variablem Anteil von Acrylsäuremethylester (ASME) und Natriumallylsulfonat (NaAS), Acrylamid (AA), Itaconsäure (IS), Polyethylenglykolacrylat (600) (PEGA), Vinylacetat (VA), Acrylsäure-2-hydroxyethylester (HEE) oder Natrium-2-acrylamido-2-methylpropansulfonat (NaAMPS) wurden hergestellt, wobei die erforderlichen Polymerisations-bedingungen mit Hilfe eines mathematischen Polymerisationsmodells ermittelt wurden.Die Fällungsuntersuchungen mit der Methode der Lichtstreuung zeigten, daß NaAS und NaAMPS einen dominierenden Einfluß haben. Bei Acrylnitril-Homopolymeren tritt eine harte Fällung auf, und die entstehenden Partikel haben eine Dichte zwischen 0,2 und 0,4 g/cm3. Zunehmender NaAS-bzw. NaAMPS-Gehalt führt ab einem Gehalt von beispielsweise ca. 0,8 Gew.-% NaAS im Monomergemisch zu einer weichen Fällung, bei der hochgequollene Partikel mit einer Dichte in der Größenordnung von 〈 1.10-2 g/cm3 entstehen. Ein Einfluß der Molmassen und des ASME-Gehaltes Konnte nicht nachgewiesen werden. Beim Acrylnitril/Acrylamid-System genügen offensichtlich 0,5 Gew.-% Allylsulfonat im Monomeransatz, um eine stabile, weiche Fällung unter Bildung hochgequollener Strukturen zu gewährleisten. Alle Proben mit den übrigen hydrophilen Cokomponenten zeigen ohne NaAS bzw. NaAMPS-Comonomer ein hartes Fäungsverhalten mit wenig gequollenen Partikeln.
    Additional Material: 4 Ill.
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  • 56
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    Angewandte Makromolekulare Chemie 195 (1992), S. 213-213 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 57
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    Angewandte Makromolekulare Chemie 195 (1992), S. 191-204 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Photovernetzung von Poly(p-hydroxystyrol) (PPHS) wird durch O2 beachtlich beschleunigt. Dies ergab sich aus der Bestimmung der Molmasse (mit Hilfe der Lichtstreumethode) und des Gelanteils nach kontinuierlicher Bestrahlung bei λinc = 254 nm. Aufgrund von Ergebnissen aus Blitzphotolyseversuchen wird der folgende Reaktionsmechanismus aufgestellt: Die Vernetzung sowohl in An-als auch Abwesenheit von O2 kommt im wesentlichen durch Kombination von Radikalen des Phenoxyltyps zustande. In Abwesenheit von O2 werden Phenoxylradikale ausschließlich durch Spaltung von O—H-Bindungen phenolischer Gruppen, die sich im angeregten Singulettzustand befinden, erzeugt. Triplett-angeregte phenolische Gruppen, die sich auch bilden, desaktivieren nicht durch Spaltung der O—H-Bindungen. Sie reagieren allerdings sehr effektiv, sofern vorhanden, mit O2. Bei dieser Reaktion entstehen HO·2- und zusätzliche Phenoxylradikale. Alle handelsüblichen und die meisten im Labor synthetisierten PPHS-Proben enthalten chemisch gebundene, chinoidartige Verunreinigungen. Durch Versuche mit niedermolekularen Modellverbindungen wurde nachgewiesen, daß triplett-angeregte chinoide Gruppen einerseits mit phenolischen Gruppen unter Bildung von Phenoxylradikalen reagieren und daß sie andererseits unreaktiv sind bezüglich der Abstraktion aliphatischer Wasserstoffatome. Die Bestrahlung von PPHS bei λinc = 254 nm bewirkt die Bildung chinoider Gruppen, die bei dieser Wellenlänge auch stark absorbieren. Die Lichtabsorption dieser Gruppen wird im Laufe der weiteren Bestrahlung zum bestimmenden Faktor hinsichtlich der photochemischen Veränderung des Polymeren.
    Notes: Light-induced crosslinking of poly(p-hydroxystyrene) (PPHS) is significantly enhanced by O2. This was evidenced by molar mass (light scattering measurements) and by gel content determinations which were performed on various polymer samples before and after continuous irradiation at λinc = 254 nm. The following mechanism was elucidated with the aid of flash photolysis studies: Crosslinking in the absence or presence of O2 is mainly due to the combination of phenoxyl type radicals. In the absence of O2 the latter are exclusively formed by O—H bond cleavage of singlet excited phenolic groups. Triplet excited phenolic groups which are also formed do not deactivate via O—H bond cleavage but react very effectively with O2. This reaction leads to the formation of HO2· and additional phenoxyl type radicals. All Commercial and most laboratory-prepared PPHS samples contain chemically bound impurities of quinoid nature. On the basis of results performed with model compounds of low molar mass, it is concluded that triplet excited quinoid groups react effectively with phenolic groups forming phenoxyl type radicals and that they are quite unreactive with respect to the abstraction of alphatic hydrogen atoms. Irradiation of PPHS at λinc = 254 nm causes the formation of quinoid groups which absorb strongly at this wavelength. Light absorption by these groups becomes a determining factor with respect to photochemical alteration in the course of further irradiation.
    Additional Material: 9 Ill.
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  • 58
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    Angewandte Makromolekulare Chemie 196 (1992), S. 21-35 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die verschiedenartigen Eigenschaften von Polymerlegierungen aus Polyoxymethylen (POM) und bis zu 20 Gew.-% chemische oberf;ächenbehandeltem Poly(tetrafluorethylen) (CPTFE) wurden untersucht und denen unbahandelter POM/PTFE- Blends gegenübergestellt. PTFE iwrd POM zugesetzt, um dessen Oberflächenabriebseigenschaften Anteil zunehmend verschlechtert. Durch die bessere Phasenanbindung in den oberflächenbehandelten POM/CPTFE- Blends konnten die doppelten Zugfestigkeiten und EModuli wie bei unbehandelten POM/PTEF- Blends erreicht werden. Mit Hilfe der Elektronenmikroskopie (SEM) konnte gezeigt werden, daß die PTEF-Agglomerate in der POM-Matrix eine Größe von 30 bis 100 μm haben, während die CPTFE-Teilchengrößbe unter 1 μum liegt.
    Notes: The various properties of the blends of polyacetal (POM) with up to 20 wt.-% chemically surface-treated poly(tetrafluoroethylene) (CPTFE) were investigated and compared with those of POM/PTFE blends. The PTFE is added to POM to improve the wear properties, however, the mechanical properties of POM/PTFE blends decrease with increasing PTFE content, but tensile strength and Young's modulus of POM/CPTFE blends are more than 2 times higher than that of the POM/PTFE blends. SEM shows that the size of inherent agglomerative PTFE is in the range of 30 to 100 μm. The particle size of major CPTFE dispersed in POM is smaller than 1 μm.
    Additional Material: 12 Ill.
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  • 59
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    Angewandte Makromolekulare Chemie 196 (1992), S. 49-61 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Hydrogele wurden aus methylmethacrylat (MMA) and N-Vinyl-2-pyrrolidon (NVP) mit 1,2,2-Trimethylolpropantrimethacrylat (TPTA) als Vernetzungsmittel hergestellt. Die Terplymerisation wurden mittels UV-strahlung (365 nm) initiiert, wobei kleine Mengen an Diethoxycetophenon (DEAP) als Photosensibilisator sowie Triethanolamin(TEA)als Beschleuniger und Verdünner verwendet wurden. Die Hydrogele wurden durch Messung des Wasserrückhaltevermögens, der Sauerstodiffusions- und permitionskoeffizienten, der mechanischen Eigenschaften und der Lichtdurchlässigkeit charakterisiert. Dabei zeigte sich, daß die Hydrogele bis zu 80 Gew.-% Wasser aufnehmen können, wobei mit steigendem Wassergtehalt deren mechanische Festigkeit drastisch sinkt. Der Ssuerstoffdiffusionskoeffizient der gequollenen Hydrogele beträgt 10-6 cm2s-1, der Sauerstoffpermeationskoeffizient 1013 cm2s-1Pa-1, und die Lichtdurchlässigkeit liegt im Bereich von 500 bis 700 nm bei über 90%.
    Notes: Hydrogels are synthesized from methyl methacrylate (MMA) and N-vinyl-2-pyrrolidone (NVP) with 1,1,1-trimethylol propane trimethacrylate (TPTA) as a crosslinking agent. It was polymerized under UV radiation (365nm) with a small amount of photosensitizer, diethoxy acetophenone (DEAP), acclerator and diluent, triethanol amine (TEA). The hydrogels were characterized by measuring the water retention, dissolved oxygen diffusivity and permeability, mechanical strength, and light transparency. The hydrogels can retain water up to 80 wt.-% and the mechanical strenght is weakened as the water content is increased in the gel. The dissolved oxygen diffusivity and permeability in the swelling hydrogels are determined to be 10-6 cm2/sec and 1013 cm2s-1 Pa-1, respectively. The light transparency is over 90% in the wave lenght ranging from 500 to 700 nm.
    Additional Material: 5 Ill.
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  • 60
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Ein Bisphenol-A-Epoxidharz wurde zunächst mit Toluylendiisocyanat, dessen eine Isocyanatgruppe mit 2-Ethylhexanol blockiert war, und dann mit unterschiedlichen Mischungen on Diethanolamin und Bis(2-methyl-isobutylketiminoethyl)amin (DKI)umgesetzt. Aus diesen Harzen mit Triethanolamin- und DKI-Endgruppen wurden durch Hydrolyse und Neutralisieren mit Essigsäure kationische Harze mit primären Amin-Endgruppen erhalten, aus denen mit geeigneten Lösungsmitteln und deionisiertem Wasser Emulsionen hergestellt wurden. Deren Eigenschaften und die Elektroabscheidung der Harze aus den Emulsionen wurden untrsucht. Der Effekt der Zugabe von hydrophoben Lösungsmitteln wie Toluol oder Hexylcellosolv (HCS) auf die Abscheidungseigenschaften wird diskutiert.
    Notes: A diglycidylether of bisphenol A epoxy resin (DGEBA) was first reacted with 2,4-toluene diisocyanate partially blocked with 2-ethylhexanol (2-EH P. B. TDI) to form modified epoxy resins, and subsequently reacted with different molar ratios of diethanolamine and bis(2-methylisobutylketiminoethyl)amine (DKI) (used as ring opening agents) to give diethanolamine/diketimine terminated resins. These resins were hydrolyzed and neutralized with acetic acid to give cationic resins containing various contents of primary amine groups in the terminal polymeric chain. These cationic resins can be dissolved in a suitable solvent and mixed with deionized water to obtain emulsions. The electrodeposition properties and characteristics of the resulting cationic resins were investigated in detail. The effects of hydrophobic solvents, such as hexyl cellosolve (HCS) and toluene, on the deposition properties of the emulsions are discussed.
    Additional Material: 11 Ill.
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  • 61
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    Angewandte Makromolekulare Chemie 196 (1992), S. 107-111 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die radikalische Polymerisation von Acrylnitril in Gegonwart verschiedener ungesättigter optischer Aufheller (FB) (Derivate des 1,3,5-Triazins) wurde untersucht. Kolorimetrische Messungen ergaben, daß mehr als 80% des optischen Aufhellers in die Polymerkette eingebaut werden. Zur Erzielung eines intensiven optischen Effektes genügt eine FB-Anfangskonzentration von 0,1 Gew.-%, bezogen auf Acrylnitril.
    Notes: The polymerization of acrylonitrile in the presence of some unsaturated, triazinebased fluorescent brighteners (FB) has been investigated. It was found colourimetrically that more than 80% of the FB is incorporated in the polymer. The initial concentration of 0.1 wt.-% is sufficient to obtain a good bleaching effect without significant decrease of the molecular weight.
    Additional Material: 2 Ill.
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  • 62
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Les polyesters thermoplastiques (PBT et PET) sont des polymères fragiles avec une résistance au choc entaillée faible. Leur renforcement peut être obtenu par extrusion réactive avec dirrérents types de copolymères élastomères de l'éthylène, contenant des fonctons à réactivité potentielle avec extrémités de chaîne acide et hydroxyle des polyesters.Deux types de copolymères ont été étudiés: Ethylène(acrylate d'éthyle/méthacrylate de glycidyle (E/EA/GMA), et éthylène/acrylate d'éthyle/anhydride maléique (E/EA/MAH). Les alliages ont été obtenu par malaxage de 10 à 25% de coppolymères avec du PBT.Le PBT présente une transition fragile, ductile lorsqu'on passe de 10 à 20% de particules dispersées de copolymère au GMA. Les gains les plus importants en résistance au choc sont obtenus en réticulant partiellement la phase dispersée, par association de copolymères en GMA et de copolymères avec MAH et catalyseur de réaction.
    Notes: Poly(butylene terephthalate) (PBT) and poly(ethylene terephthalate) (PET) are brittle polymers with poor notched impact strength. Their toughening can be achieved by melt blending with different types of rubbery ethylene copolymers containing functions having potential reactivity with the hydroxy and carboxy end groups in polyesters.Two types of ethylene copolymers were investigated: ethylene/ethyle acrylate/glycidyl methacrylate (E/EA/GMA) and ethylene/ethyl acrylate/maleic anhydride (E/EA/MAH) copolymers. The blends were obtained by reactive extrusion of PBT with 10 to 25% of copolymers.PBT blends undergo a brittle to ductile transition by toughening with GMA copolymer between 10 and 20% of rubbery phase. The most effective toughening could be achieved by a partial crosslinking of the rubbery particles obtained by associating GMA and MAH copolymers and a reaction catalyst.
    Additional Material: 5 Ill.
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  • 63
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    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 196 (1992), S. 101-106 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Orientierung (Neigungswinkel ϕ) von thermotropen Flüssigkristallen (LC) an der Grenzfläche zu polymerbeschichteten Substraten wird nicht nur durch den numerischen Wert der Oberflächenspannung \documentclass{article}\pagestyle{empty}\begin{document}${\rm \gamma }_{\rm S} {\rm }\left( {{\rm \gamma }_{\rm S} {\rm = \gamma }_{\rm S}^{\rm d} {\rm + \gamma }_{\rm S}^{\rm p} } \right)$\end{document} bestimmt. Das Verhältnis zwischenden dispersiven und polaren Anteilen an \documentclass{article}\pagestyle{empty}\begin{document}${\rm \gamma }_{\rm S} {\rm }\left( {{\rm \gamma }_{\rm S}^{\rm d} {\rm : \gamma }_{\rm S}^{\rm p} } \right)$\end{document} beeinflußt ebenfalls die Orientierung der LC-Moleküle an der Substratoberfläche. Als Polymere wurden ein Polyimid und ein Midgruppenhaltiges Styrol/Maleinsäureanhydrid-Copolymeres verwendet.
    Notes: The orientation (tilt angle ϕ) of thermotropic liquid crystals (LC) on the interface to a polymer-coated surface is not only determined by the numerical value \documentclass{article}\pagestyle{empty}\begin{document}${\rm \gamma }_{\rm S} {\rm }\left( {{\rm \gamma }_{\rm S} {\rm = \gamma }_{\rm S}^{\rm d} {\rm + \gamma }_{\rm S}^{\rm p} } \right)$\end{document} of the substrate surface tension. However, the ratio between the dispersive and the polar part of \documentclass{article}\pagestyle{empty}\begin{document}${\rm \gamma }_{\rm S} {\rm }\left( {{\rm\gamma }_{\rm S}^{\rm d} {\rm : \gamma }_{\rm S}^{\rm p} } \right)$\end{document} also influences the LC orientation on the substrate surface. A polyimide and an amide-modified styrene/maleic anhydride copolymer were used as polymers.
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  • 64
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    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 195 (1992), S. 129-137 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Epoxidharze aus Bisphenol A wurden mit neuen Diphenolen, die Imidgruppen enthalten, modifiziert, um die thermischen Eigenschaften zu verbessern. Die verwendeten Diimiddiphenole wurden aus Dianhydriden und Aminophenolen durch Kondensation hergestellt. Die Diimiddiphenole und die modifizierten Harze wurden durch IR- und NMR-spektroskopische Messungen charakterisiert. Das thermische Verhalten wurde anhand von DSC- und TGA-Messungen untersucht.
    Notes: Epoxy resins derived from Bisphenol A have been modified with new diphenols containing imide moieties in order to improve their thermal properties. The diphenols have been synthesized from dianhydrides and aminophenols by condensation reactions. Diphenols as well as modified resins have been characterized by IR and NMR spectroscopy. The thermal characteristics were evaluated by DSC and TGA.
    Additional Material: 3 Ill.
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  • 65
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    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 195 (1992), S. 165-170 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The structural transformation of a molecular complex (MC) of polyoxyethylene and urea on cooling from the molten state has been investigated by DSC and X-ray analysis. A high-temperature polymorphic from of the MC was found to be formed, which transforms into the known crystal form of the MC with a hexagonal crystal modification on cooling.
    Notes: Die Strukturveränderungen eines Molekülkomplexes (MK) aus Polyoxyethylen und Harnstoff beim Abkühlen aus dem geschmolzenen Zustand werden kalorimetrisch und röntgenographisch untersucht. Es wird festgestellt, daß eine polymorphe Hochtemperaturform des MK entsteht, die beim Abkühlen in die bekannte Kristallform des MK mit hexagonaler Kristallmodifikation übergeht.
    Additional Material: 3 Ill.
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  • 66
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    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 196 (1992), S. 143-154 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Das Anfangsstadium der Oxidation von Lactamen wurden im Temperaturbereich 70-120°C Cuntersucht. Es wurde festgestellt, daß Pyrrolidon und Piperidon bedeutend schneller oxidiert werden als die sieben-, acht- und dreizehngliedrigen Lactame sowie lineare N-Alkylamide. Die hohe Oxidierbarkeit der fünf- und sechsgliedrigen Lactame kann der leichteren homolytischen Spaltung der N- vicinalen C—H Bindung und der unterschiedlichen Reaktivität der Lactamradikale im Wachstuschritt der Kettenoxidation zugeschrieben werden.
    Notes: The initial stage of oxidation of lactams was studied in the temperature range 70-120°C. It was found that pyrrolidone and piperidone are oxidized essentially more easily than the seven-, eight-, nine- and thirteen-membered lactams as well as linear N-alkylamides. The high oxidizability of the five- and six-membered lactams may be attributed to the easier homolytic splitting of the N-vicinal C—H bond and to the different reactivity of lactam radicals in the propagation step of the chain oxidation.
    Additional Material: 5 Ill.
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  • 67
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    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 196 (1992), S. 127-141 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The relative chain transfer constant for sodium allylsulfonate (NaAS) in the copolymer system acrylonitrile (AN)/methylacrylate (MA) in dimethylformamide (DMF) was determined to be Cx = 0,04 ± 0.01, independent of the initiator used (azoisobutyronitrile, ammoniumperoxodisulfate).The chain transfer reaction explains the influence of NaAS on the polymerization degree, but not the concentration dependence of the copolymerization reactivity ratio r1 · r1 depends on the transfer reaction only in a range of 1 - 5%.The extended Debye-Hückel theory for dilute electrolytes has been successfully tested for a quantitative dependence of r1 from NaAS concentration. The resultant r10-value for infinite dilution of NaAS obviously depends on the acrylonitrile concentration, but only to a small extent (e.g. r10 = 0.32 for [AN] =- 4.26 mol/l). This theory provides comfortable access to resolve the nonideal AN/NaAS copolymerization. This approach may be generally applicable to copolymerizations of monomers with dissociated groups.
    Notes: Im Copolymerisationssystem Acrylnitril (AN)/Methylacrylat(MA) mit Natriumallylsulfonat (NaAS) in Dimethylformamid wurde die relative Übertragunskonstante zum NaAS Cx = 0,04 ± 0,01 unabhängig vom verwendeten Initiator (Azoisobuttyronitril, Ammoniumperoxodisulfat) ermittelt. Die Übertragunsreaktion beschreibt den Einfluß des NaAS auf den Polymerisationsgrad, sie beeinflußt jedoch den Copolymerisationsparameter r1 nur in der Größenordung von 1 bis 5% und kann damit die Konzentrationsabhängigkeit von r1 nicht erklären.Mit Hilfe der erweiterten Debye-Hückel-Theorie für verdünnte Elektrolyte wird die Abhängigkiet des r1-Wertes von der NaAS- Konzentration beschrieben. Der sich daraus für unendliche Verünnung des NaAS ergebende r10-Wert ist offensichtlich noch gerinfügig von der Acrylnitrilkonzentration abhägig. Er liegt beispielsweise für [AN] = 4, 26 mol/1 bei r10 = 0, 32. Damit wurde zum ersten Mal das nichtideale Copolymerisationsverhalten im untersuchten System erkärl. Das Vorgehen sollte verallemeinerungsfähig sein und generell auf das Copolymerisationsverhalten von Monomeren mitdissoziierten Gruppen angewendet werden können.
    Additional Material: 4 Ill.
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  • 68
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    Angewandte Makromolekulare Chemie 196 (1992), S. 169-177 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Katalase wurde durch photoinduzeirte Propfpolymerisation auf mikroporöse polymere Trägermembranen immobilisiert. Die katalytische Aktivität für Zersetzung von Wasserstoffperoxid unter Ultrafitrationsbedingungen wurde mittels eines Rezirkulationsapparates untersucht. Die Membranen zeigten ein sehr gutes katalytisches Verhalten; die Enzymreaktion fand ausschließlich in der Membranstruktur statt. Anfangsreaktionsgeschwindigkeiten, gemessen in einem Temperaturbereich von 5-35°C als Funkation der Substratkonzentration und der Menge des immobilisierten Enzyms pro Einheit Membranoberfäche zeigten, daß sich der Reaktionsmechanismus der Katalase durch die Immobilisierung nicht verädert.
    Notes: Catalase has been immobilized in membranes prepared by photoinduced grafting onto microporous polymeric supports and its catalytic activity on hydrogen peroxide decomposition has been studied under ultrafiltration conditions by means of a recirculation apparatus. The membranes showed a very good catalytic performance and the enzyme reaction took place exclusively within the membrane structure. Initial reaction rates measured in the temperature range 5 - 35°C as a function of both substrate concentration and enzyme amount immobilized per unit membrane surface indicate that the mechanism of action of catalase is not altered after immobilization.
    Additional Material: 2 Ill.
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  • 69
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The network formation process of bisphenol A-diglycidylether and 4,4′-diaminodiphenylmethane was investigated by measuring the torque, the conductivity and the soluble part of the crosslinking system. The activation energy for the curing process was estimated from gel time. The volume shrinkage during network formation was measured. The influence of N,N-dimethylbenzylamine as accelerator was discussed.
    Notes: Der Aufbau von Netwerken aus Bisphenol A-Diglycidylether und 4,4′-Diaminodiphenylmethan wurde durch Messung des Drehmomentes, der Leitfähigkeit und durch Bestimmung der löslichen Anteile des vernetzenden System untersucht. Aus den Gelzeiten wurden die Aktivierungsenergie für den Vernetzungsprozeß bestimmt. Außerdem wurde die während der Vernetzung aufretende Volumenschwindung gemessen. Der Einfluß von N, N-Dimethylbenzylamin als Beschleuniger auf den Vernetzungsprozeß wird diskutiert.
    Additional Material: 6 Ill.
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  • 70
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The UV-laser induced surface modification of various types of high-performance fibers is investigated. Due to the high UV-absorption coefficients, the well-known effect of UV-laser induced etching (ablation) is observed with all fiber types. Furthermore, the relaxation of orientated macromolecules leads to a characteristic structuring of the fiber surface. For a possible controlled use of this physical surface modification, exact conditions for the treatment in view of textile applications are determined. Useful constants like threshold of ablation, etching rate and structuring constants are measured for all fiber types.
    Notes: Die Oberflächenbehandlung von unterschiedlichen Hochleistungsfasertypen mit gepulstem UV- Laserlicht wird untersucht. Bedingt durch die hohen UV-Absorptionskoeffizienten dieser Materialien wird der bekannte Effekt des UV-laserinduzierten Abtrags (Ablation) bei allen Fasern beobachtet. Zusätzlich werden durch die Relaxation der orientierten Makromoleküle charakteristische Strukturierungen auf der Faseroberfläche ausgebildet. Für einen möglichen kontrollierten und gezielten Einsatz dieser physikalischen Oberflächenmodifizierung in textilen Anwendungen werden die gnaunen Bedingungen der Laserbestrahlung ermittelt und beschieben. Darüber hinaus werden geeignete Konstanten der Laserbearbeitung wie Ablationsschwellenenergie, Ätzraten und Strukturierungskonstanten für verschiedene Fasertypen bestimmt.
    Additional Material: 8 Ill.
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  • 71
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    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 198 (1992), S. 165-178 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Polymerisation von Dimethyl-diallyl-ammoniumchlorid in konzentrierter wäßriger Lösung mit Persulfat als Initiator kann bis zu hohen Umsätzen mit einem Modell beschrieben werden, in dem folgende Teilreaktionen berücksichtigt werden: a)Primärradikalbildung durch aktivierten Initiatorzerfall sowie Redoxreaktion von S2O2-8 und Cl-b)Kettenwachstum über Monomerkationassoziate undc)Kettenabbruch durch Kombination von cyclisierten Polymerradikalen untereinan der und mit Chloratomen.Für die Polymerisationsgeschwindigkeit wird ein Zeitgesetz hergeleitet, für dessen Konstanten und Parameter numerische Werte ermittelt wurden.
    Notes: The polymerization of dimethyl diallyl ammonium chloride in concentrated aqueous solution with persulfate as an initiator can be described up to high conversion by a kinetic model including a)formation of primary radicals by activated initiator decomposition as well as by redox reaction of S2O82- and Cl-,b)chain propagation via monomer cation associates andc)termination by combination of cyclized polymer radicals between each other or with chlorine atoms.A kinetic expression for the rate of polymerization is presented; rate constants and model parameters have been determined.
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  • 72
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    Angewandte Makromolekulare Chemie 198 (1992), S. 199-199 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 73
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    Angewandte Makromolekulare Chemie 198 (1992), S. 179-190 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Polymere mit über eine C—C-Verknüpfung an hochvernetztem Polystyrol kovalent gebundenen, makrocyclischen Amiden wurden durch die Reaktion polymergebundener Malonsäureester-Gruppen mit offenkettigen Diaminen dargestellt. Die Reaktion von vernetztem, chlormethyliertem Polystyrol mit makrocyclischen und offenkettigen Aminen führt zu Polymeren mit kovalenter Bindung über eine C—N-Verknüpfung. Die erhaltenen funktionalisierten Polymeren wurden hinsichtlich der Adsorption von Cu(II)-, Ni(II)- und Co(II)-Ionen aus wäßriger Lösung untersucht.
    Notes: Polymers containing moieties of amides covalently bound to highly crosslinked polystyrene by C—C connections were prepared via a polymer-bound malonic ester group in the reaction with open-chain diamines. The reaction of crosslinked, chloromethylated polystyrene with macrocyclic and open-chain amines results in covalent binding by C—N-connection. The synthesized functionalized polymers were investigated for uptake of Cu(II), Ni(II) and Co(II) ions from aqueous solutions.
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  • 74
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    Angewandte Makromolekulare Chemie 199 (1992), S. 1-6 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Poly(phenylphosphindiylterephthaloyl), ein neues phosphorhaltiges Polymeres, wurde durch Lösungspolykondensation von Dilithium(phenyl)phosphin mit Terephthaloylchlorid bei niedriger Temperatur hergestellt. Es ist in polaren aprotischen Lösungsmitteln löslich; die inhärente Viskosität in DMF bei 30°C beträgt 19 ml/g. Das Polymere wurde mittels Elementaranalyse sowie IR- und 1H-NMR-Spektroskopie charakterisiert. TGA-Messungen ergeben, daß das Polymere in Luft bis 250°C stabil ist; es ist selbstverlöschend.
    Notes: Poly(phenylphosphinediylterephthaloyl), a novel phosphorus-containing polymer, was synthesized by low-temperature solution polycondensation of dilithio(phenyl)-phosphine with terephthaloyl chloride. The resulting polymer is soluble in polar aprotic solvents, having inherent viscosity of 19 ml/g in DMF at 30°C. The polymer was characterized by elemental analysis, IR and 1H-NMR spectroscopy. TGA data show that the polymer is stable up to 250°C in air. The polymer was found to be self-extinguishing.
    Additional Material: 3 Ill.
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  • 75
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Es wird eine neue Methode für die Erweiterung des Meßbereiches der Ausschlußchromatographie, gekoppelt mit Lichtstreuung (SEC/LALLS), zu höherer molarer Masse, vorgestellt. Diese Methode nützt den Effekt, daß das Lichtstreusignal oft schon bei wesentlich kleineren Werten des Elutionsvolumens, also hoheren Werten der molaren Masse erfaßbar ist als das Konzentrationssignal und berücksichtigt dabei die Peakverbreiterung in der SEC. Das betreffende Rechenverfahren wird für den Fall einer logarithmischen Normalverteiung und einer wahrscheinlichsten Verteilung getestet. Im Falle von Polypropylen mit logarithmischer Normalverteilung (M̄W = 420 000 und M̄n = 99 000) kann der durch SEC/LALLS erfaßte Bereich der molaren Masse um einen Faktor von ca. 10 erweitert werden; bei einer wahrscheinlichsten Verteilung (M̄n = 100 000) liegt die erreichbare Erweiterung des Meßbereiches der molaren Masse beieinem Faktor von ca. 2.
    Notes: A new method for the extension of the measuring range of size exclusion chromatography coupled with light scattering (SEC/LALLS) to higher molar mass is presented. This method uses the fact that the light scattering signal can often be detected already at considerable smaller values of the elution volume (i. e. higher values of molar mass) than the concentration signal; furthermore, it takes into account the peak broadening effect in SEC. This procedure is tested for the case of a logarithmic normal distribution and a most probable distribution of molar mass. In the case of polypropylene with a logarithmic normal distribution (M̄w = 420 000, M̄n = 99 000), the range of molar mass covered by SEC/LALLS can be extended by a factor of about 10; with a most probable distribution (M̄n = 100 000), the attainable extension in molar mass assumes a factor of about 2.
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  • 76
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    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 199 (1992), S. 45-63 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Because of the interest in their possible application as biologically degradable polymers, the isotherms of sorption of water vapour by native and thermoplastic starch were measured. The thermomechanical treatment of starch and the insertion of glycerol as softener lead to the disappearance of the hysteresis and to the transition from a Type II to Type III isotherm. A theory, describing the sorption behaviour of swellable sorbents, is introduced and its statements are discussed by means of experimental results. The theory allows to draw conclusions on the molecular behaviour during sorption.
    Notes: Es wurden Wasserdampf-Sorptionsisothermen von nativer und thermoplastischer Stärke gemessen. Die thermisch-mechanische Behandlung der Stärke und das Einfähren von Glyzerin als Weichmacher fährt zum Verschwinden der Hysterese und zum Übergang von der Typ II in eine Typ III Isotherme. Eine Theorie, welche das Sorptionsverhalten von quellbaren Sorbentien gut beschreibt, wird kurz eingeführt und anhand der experimentellen Daten ihre Aussagen diskutiert. Die vorgestellte Theorie erlaubt wegen der physikalischen Bedeutung der Parameter Rückschlüsse auf die molekularen Vorgänge während der Sorption. Die Motivation zur Untersuchung des Sorptionsverhaltens von thermoplastischer Stärke ist deren möglicher Einsatz als biologisch abbaubarer Kunststoff.
    Additional Material: 7 Ill.
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  • 77
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: In order to solve the problem of polymer swelling which limits the resolution of negative resists, we have developed new resists where the swelling does not appear. For our study, we developed resists including polymers containing the tetrathiafulvalenylcarbonyloxymethyl radical and dibromotetrachloroethane. In order to study the influence of the nature of the radical bearing the tetrathiafulvalene unit in the polymers on the microlithographic properties of these resists, we also studied polymers containing the tetrathiafulvalenylphenoxymethyl radical. The resists have been tested under UV irradiation. The dependence of resist sensitivity on molecular weight is reported.
    Notes: Pour résoudre le phéomène de gonflement qui limite la résolution des résines microlithographiques classiques, nous nous sommes intéressés à de nouvelles résines avec lesquelles ce phénomène n'apparait pas. Nous avons retenu pour notre étude les résines R qui renferment en mélange un polymère porteur de radicaux tétrathiafulvalénylcarbonyloxyméthyles et le dibromotétrachloroéthane. Afin de voir l'influence de la nature du radical porteur de l'unité tétrathiafulvalène dans le polymtrè sur les propriétés microlithographiques des résines R, nous nous sommes également intéressés aux polymères renfermant des radicaux tétrathiafulvalénylphénoxymethyles. Les résines R ont été testées sous irradiation UV. Leurs sensibilités dépendent en outre de la valeur de la masse molaire du polymèr.
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  • 78
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    Angewandte Makromolekulare Chemie 199 (1992), S. 33-44 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Hochfeste Polyethylen- (HSPE), Polypropylen- (PP), Polyethylenterephthalat-(PET) und Polyvinylalkohol-(PVA) Textilgarne wurden unter Anwendung des entwickelten kontinuierlichen Einweichprozesses mit verschiedenen funktionellen Monomeren, wie beispielsweise Acrylsäure (AA), Acrylamid (AM), Glycidylacrylat (GA) und 4-Vinylpyridin (VP) oberflächenfotogepfropft. Die Einfärbbarkeit der oberflächenmodifizierten Garne mit verschiedenen Textilfarbstoffen wurde untersucht. Im allgemeinen wurde eine erhebliche Verbesserung der Einfärbbarkeit beobachtet. Die Farbstoffaufnahme der oberflächenfotogepfropften Fasern wird von vielen Faktoren beeinflußt, beispielsweise von der Art der Faser, der Menge und den Eigenschaften des auf die Oberfläche der Fasern gepfropften funktionellen Monomeren, der Art des Textilfarbstoffs usw. Die Faseroberflächen, auf die ein Monomeres mit basischen Gruppen wie Acrylamid und 4-Vinylpyridin gepfropft wurde, lassen sich mit einem sauren Farbstoff wirkungsvoll einfärben. Dagegen läßt sich eine Faseroberfläche, auf die ein saures funktionelles Monomeres gepfropft wurde, leicht mit basischen Farbstoffen in tiefen Farbtönen einfärben. Die Farbstoffaufnahme steigt stetig mit zunehmender Pfropfung, in ESCA-Spectren als relative Intensitaten relevanter Linien gemessen. Die nicht gepfropften HSPE-, PP-, und PET-Fasern können mit bestimmten Farbstoffen in gewissem Maße eingefärbt werden. Bei der vorliegenden Arbeit erhöhte sich die Farbstoffaufnahme bei HSPE-Fasern, die mit GA gepfropft und mit dem Metallkomplexfarbstoff IO eingefärbt wurden, um das 3,4fache, bei PP-Fasern, die mit AA gepfropft und mit dem basischen Farbstoff MB eingefärbt wurden, um das 7,9fache, bei PET mit AM und dem Direktfarbstoff SL um das 6,1fache, bei PVA mit VP und dem sauren Farbstoff TE um das 15,3fache.
    Notes: High-strength polyethylene (HSPE), polypropylene (PP), poly(ethylene terephthalate) (PET), and poly(vinyl alcohol) (PVA) textile yarns have been surface-photografted with various functional monomers, such as acrylic acid (AA), acrylamide (AM), glycidyl acrylate (GA) and 4-vinyl pyridine (VP), by means of the continuous presoaking process developed. The dyeing of these surface-modified yarns with various textile dyes has been investigated. In general, considerable improvements of dyeability have been observed. The dye adsorption of the surface-photografted fibers is influenced by many factors, such as type of fiber, amount and properties of the functional monomer grafted on the surface of the fibers, type of textile dye, etc. The fibers surface-grafted with a monomer containing basic groups, such as acrylamide and 4-vinyl pyridine, are efficiently dyed with an acid dye. Conversely, a fiber surface-grafted with acidic functional monomer is easily dyed to deep shades with basic dyes. The dye adsorption increases monotonically with increasing grafting measured in ESCA spectra as relative intensities of relevant lines. The ungrafted HSPE, PP and PET fibers can be dyed to some extent with certain dyes. In the present work, the dye adsorption increased by 3.4 times for HSPE fiber grafted with GA and dyed with the metal complex dye IO, by 7.9 times for PP fiber grafted with AA and dyed with the basic dye MB, by 6.1 times for PET with AM and with the direct dye SL, and by about 15.3 times for PVA with VP and with the acid dye TE.
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  • 79
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 199 (1992), S. 65-74 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die thermische Stabilität von Acrylnitril-Copolymeren wurde mittels DSC untersucht, um den Einfluß von halogenierten Comonomeren mit Carboxygruppen auf die Stabilisierung von PAN zu präfen. Es wird gezeigt, daß die Aktivierungsenergie fär die Cyclisierung des AN/Bromacrylsäure(BrAA)-Copolymeren (86,2 kJ/mol) deutlich niedriger als die der Copolymeren mit Chloracrylsäure (ClAA, 158 kJ/mol), Acrylsäure (AA, 128 kJ/mol) und Itaconsäure (IA, 102 kJ/mol) ist. Das erlaubt eine Stabilisierung bei häherer Temperatur und eine Verkürzung der Stabilisierungszeit. ClAA ist BrAA bezäglich der Stabilisierungseffektivität nicht überlegen. Der Mechanismus der Cyclisierung von AN-Copolymeren mit halogenierten, carboxygruppenhaltigen Comonomeren wird diskutiert.
    Notes: The thermal stability of AN copolymers was studied by DSC technique in order to get information on the influence of comonomers containing halogenated carboxylic acid on the stabilization of PAN. It is shown that the activation energy of cyclization is reduced in the case of the copolymer with bromoacrylic acid (BrAA, 86.2 kJ/mol) compared with chloroacrylic acid (ClAA, 158 kJ/mol), acrylic acid (AA, 128 kJ/mol) and itaconic acid (IA, 102 kJ/mol). Copolymer AN/BrAA permits the stabilization at higher temperature than AN/IA and AN/AA, helping to shorten the stabilization time. It is proved that comonomer ClAA is not superior to BrAA in the effectiveness of thermal stabilization. The mechanism of the cyclization reaction of AN copolymer containing halogenated carboxylic acid is discussed.
    Additional Material: 3 Ill.
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  • 80
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 199 (1992), S. 75-85 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Es wurden neue unsymmetrische cycloaliphatische Bisepoxyderivative hergestellt. Die unterschiedliche Reaktionsfahigkeit der zwei Oxiranringe (cycloaliphatisch und glycidylisch) gegenüber Carbonsäure wurde untersucht, wobei eine normale und anomale Ringöffnung der Glycidylgruppen beobachtet wurde. Eine Homopolymerisation des Oxirans wurde ebenfalls beobachtet. Mit Hilfe der 13C-NMR-Spektroskopie wurde die Struktur der Polymeren ermittelt. Die neuen Epoxidharze zeigen gute thermische Eigenschaften.
    Notes: New bisepoxy unsymmetrical cycloaliphatic derivatives have been synthesized. The different reactivity of both oxirane rings (cycloaliphatic and glycidylic) has been tested against carboxylic acids giving rise to normal and abnormal opening to the glycidyl group. Homopolymerization reaction was also observed. Polymer structures were identified by 13C-NMR spectroscopy. Thermal analysis carried out allowed to confirm their good thermal properties.
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  • 81
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 194 (1992), S. 119-131 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: N,N′-4,4′-Diphenylmethane-bismaleimide (BMI) was oligomerized in semisolid phenolnovolak epoxide-resin (EP) up to P̄n = 10. The morphology of the novolakcured EP-BMI solid resins is a two-phase structure. It consists in a homogeneous EP-BMI phase of an interpenetrating polymer network (IPN) and a BMI phase. The dynamic-mechanical properties depend on the overall weight fraction w2 of BMI and on the degree of oligomerization (P̄)n of BMI. The relative shear modulus of the EP-EMI resin in the rubber state shows that both phases can be coherent. The glass transition temperature (Tg) can be correlated with the degree of oligomerization of the BMI, for instance Δ P̄n ≡ 10 corresponds to Δ Tg ≡ 35 K and Δ wx2 ≡ 0,25 (weight fraction of BMI in the homogeneous EP-BMI phase). Surprisingly, the breaking strength remains constant.
    Notes: N,N′-4,4′-Diphenylmethan-bismaleimid (BMI) wurde in halbfesten Phenolnovolak-Epoxidharzen (EP) bis P̄, = 10 oligomerisiert. Die novolakgehärteten EP-BMI-Festharze bilden eine Zweiphasenstruktur, bestehend aus einer EP-BMI-Mischphase der beiden sich durchdringenden Netzwerke (interpenetrating polymer network, IPN) und einer BMI-Phase. Die dynamisch-mechanischen Eigenschaften hängen vom Gesamt-BMI-Anteil w2 und vom Oligomerisierungsgrad P̄n des BMI ab. Der relative Schubmodul des EP-BMI-Harzes im kautschukelastischen Zustand zeigt, daß beide Phasen kohärent sein können. Die Glastemperatur Tg korreliert mit dem Oligomerisierungsgrad, z. B. entspricht ΔPn ≡ 10 einem ΔTg ≡ 35 K und einem BMI-Anteil Δ wx2 ≡ 0,25 in der Mischphase. Die Bruchzahigkeit bleibt unerwartet konstant.
    Additional Material: 8 Ill.
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  • 82
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Handelsübliche Araldit™-Polymere wurden mit Zimtsäure- bzw. Furanacrylsäurechlorid modifiziert und über [2 + 2]-Cycloaddition photochemisch vernetzt. Die Glasübergangstemperaturen der entstandenen Polymeren betragen bis zu 130°C bei Dielektrizitätskonstanten von ∊r = 3.0. Daher können diese Polymeren in Mehrlagenmikroverdrahtungen verwendet werden. Zahlreiche wohldefinierte, multifunktionelle Modifikatoren wurden synthetisiert und deren Einfluß auf die Polymerisation und die Eigenschaften der Araldit™-Polymeren eingehend untersucht.
    Notes: Commercially available Araldite™-type polymers have been modified with cinnamic and furan acrylic acid chlorides. The polymers were photochemically crosslinked via a [2 + 2] cycloaddition. The resulting polymers show glass transition temperatures up to 130°C and dielectrical constants of ∊r = 3.0. Therefore, these polymers can be applied as permanent resists in multi-layered wiring structures. Numerous well-defined multifunctional modifiers have been synthesized. The effect of those modifiers on the polymerization and properties of the araldite-type polymers has been studied in some detail.
    Additional Material: 1 Ill.
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  • 83
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    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 200 (1992), S. 61-76 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The photoinduced free radical crosslinking of silicone containing pendent acrylate or methacrylate groups was investigated by swelling measurements. A modified swelling test was applied to observe the network formation as a function of several parameters. The results show that the network density of the crosslinked polymers is a function of the light intensity, the exposure time, the acrylate content, the molecular weight of the uncrosslinked silicone acrylate and also of the length of the spacer group between the acrylate unit and the silicone backbone. Oxygen has only an influence on the polymerization kinetics, but it does not influence the network density.From the δB, -values of crosslinked silicone acrylates and silicone containing vinyl groups it is possible to analyze the structure of the network as a function of the olefinic group. The χ-parameters of both silicone types are of the same magnitude in the same concentration range.Kinetics investigations demonstrate that the order of the network formation is nearly unity. This result agrees with the polymerization kinetics.By means of swelling measurements it is also possible to study the influence of hydrogen siloxane additives as hydrogen transfer reagents.
    Notes: Die photoinduzierte radikalische Vernetzung von Siliconacrylaten bzw. -methacrylaten wurde mit Hilfe von Quellungsmessungen untersucht, wobei ein modifizierter Quellungstest erlaubt, die Netzwerkbildung als Funktion verschiedener Parameter zu betrachten. Die Ergebnisse zeigen, daß die Netzwerkdichte eine Funktion der Lichtintensität, der Bestrahlungszeit, des Acrylatgehalts, der Molmasse des unvernetzten Silicons und auch der Länge der Spacergruppe zwischen Acrylateinheit und dem Siliconrückgrat ist. Sauerstoff besitzt dagegen nur einen Einfluß auf die Polymerisationskinetik, nicht aber auf die Netzwerkdichte.Aus dem Vergleich der δB, -Werte der vernetzten Siliconacrylate und der vernetzten Vinylsilicone kann geschlossen werden, daß die Netzwerkstruktur auch vom Typ der olefinischen Gruppen abhängt. Die χ-Parameter besitzen jedoch im gleichen Konzentrationsbereich die gleiche Größe.Kinetische Untersuchungen zeigen, daß die Netzwerkbildung nach einem Zeitgesetz erster Ordnung verläuft. Dieses Ergebnis steht im Einklang mit der Polymerisationskinetik.Mit Hilfe der Quellexperimente ist es auch moglich, den Einfluß von H-Siloxanzusätzen als Wasserstoffüberträger zu untersuchen.
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  • 84
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 194 (1992), S. 133-148 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The copolymerization of butadiene with a technical divinylbenzene fraction was investigated to study the modification of cis-1,4 polybutadiene. Beside the Ziegler-Natta-catalyst nickeloctanoate/bortrifluoride/aluminiumtriethyl, another catalytic system consisting of nickeloctanoate/titaniumtetrachloride/aluminiumtriethyl was used, which allows to polymerize more divinylbenzene because of its higher activity toward vinylaromates. With the help of spectroscopical, pyrolysis-gaschromatographical and thermoanalytical methods one can obtain relations between glass-, crystallization- and melting temperature and the microstructure of the polymer. It can be shown that not only the divinylbenzene but also the trans-1,4- and the 1,2-vinyl units are statistically distributed in the polymer. By this, beside the pyrolysis-gaschromatography, particularly the differential scanning calorimetry is a useful tool to characterize the structure of partially crosslinked polymers obtained from polymerization of technical fractions.
    Notes: Im Rahmen von Arbeiten zur Modifizierung des cis-1,6Polybutadiens wurde die Copolymerisation von Butadien und einer Divinylbenzolfraktion, insbesondere der Bereich mit kleinen Divinylbenzolgehalten, untersucht. Neben dem Ziegler-Natta-Katalysator Nickeloctanoat/Bortrifluoridetherat/Aluminiumtriethyl kam auch ein Nickeloctanoat/Titantetrachlorid/Aluminiumtriethyl-System zur Anwendung, welches es durch seine höhere Aktivität gegenüber Vinylaromaten ermöglicht, großere Mengen der Divinylbenzolfraktion zu polymerisieren. Durch die Anwendung von spektroskopischen, pyrolysegaschromatographischen und thermoanalytischen Charakterisierungsmethoden können Beziehungen zwischen den erhaltenen Glas-, Kristallisations- und Schmelztemperaturen und der Mikrostruktur des Polymeren hergestellt werden. Es zeigt sich, daß sowohl das Divinylbenzol als auch die trans-1,4 bzw. die 1,2-Vinyl-Einheiten statistisch in das Polymere eingebaut werden. Damit eignet sich neben der Pyrolysegaschromatographie besonders die Differential Scanning Calorimetry als eine einfache Methode zur Charakterisierung der Struktur von aus technischen Fraktionen erhaltenen und teilweise vernetzten Polymerproben.
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  • 85
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Optisch hochreine Gläser wurden aus Polystyrol (PS), Polymethylmethacrylat (PMMA) und statistischen Styrol-Methylmethacrylat-Copolymeren (S-MMA) hergestellt. Die an diesen Gläsern gemessene Lichtstreuung hängt von der chemischen Zusammensetzung des Polymeren und dem Brechungsindex des zugesetzten Weichmachers ab. Ein isorefraktiver Weichmacher verringert die Streuwerte der S-MMA-Copolymeren, hat aber keinen signifikanten Einfluß auf das Streuverhalten von PMMA. Ein Weichmacher mit einem vom Polymeren verschiedenen Brechungsindex verschlechtert die Streuwerte in allen untersuchten Fällen. Es wird gezeigt, daß ein isorefraktiver Weichmacher die Dämpfungseigenschaften von aus dem Copolymeren S-MMA 2/1 gezogenen polymeren Lichtleitern verbessert.
    Notes: High optical purity polystyrene (PS), poly(methyl methacrylate) (PMMA) and styrene-methyl methacrylate statistical copolymers (S-MMA) were prepared. Light scattering measured on polymeric glasses depends on the chemical composition of the polymer and on the refractive index of the plastifier added. An isorefractive plastifier reduces considerably the scattering values for the copolymers S-MMA, while having no significant effect on the scattering of PMMA. A plastifier with a refractive index different from that of the polymer raises distinctly the light scattering values in all cases. It has been shown that the isorefractive plastifier has a favourable effect on attenuation loss of polymeric optical fibers (POF) obtained from the copolymer S-MMA 2/1.
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  • 86
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: ABS/TPU- und SAN/TPU-blends were investigated on the basis of the analysis of viscoelastic behaviour of the components for characterization of the formation of morphology in melt mixing processes. Blends mixed in a laboratory kneeder and extruded from a high pressure capillary viscosimeter under definite conditions were characterized concerning their phase morphology by transmission electron microscopy. The types of morphology predicted by the help of rheological analysis could be confirmed by electron micrographs and quantitative analysis of morphology. It becomes evident, that the ratio of viscosity of the components has the primary influence on the formation of morphology in the blends. But also thermomechanically induced molecular destruction processes and thermodynamic interactions as well as connecting crystallisation conditions for the TPU-phase are not negligible with regard to resulting phase morphology.
    Notes: An ABS/TPU- bzw. SAN/TPU-Blends wurden Untersuchungen zur Morphologiebildung beim Schmelzemischen auf der Basis der Analyse des viskoelastischen Verhaltens der Komponenten angestellt. Unter definierten Bedingungen im Laborkneter gemischte und unter definierten Bedingungen mittels Hochdruckkapillarviskosimeter extrudierte Blendproben wurden hinsichtlich ihrer Phasenmorphologie elektronenmikroskopisch charakterisiert. Die mittels der rheologischen Analyse prognostizierten Morphologietypen und Morphologiebildungsmechanismen konnten anhand der elektronenmikroskopischen Aufnahmen und der quantitativen Morphologieanalyse bestätigt werden. Es zeigte sich, daß das Viskositätsverhältnis der Komponenten primären Einfluß auf die Morphologiebildung ausübt. Darüber hinaus sind auch thermomechanisch induzierte molekulare Abbauvorgänge und thermodynamische Wechselwirkungen sowie damit im Zusammenhang stehende Kristallisationsbedingungen für die TPU-Phase hinsichtlich der resultierenden Phasenmorphologie nicht zu vernachlässigen.
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  • 87
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 194 (1992), S. 189-200 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Stabilität von Verbindungen von Polypropylen (PP) und Polycarbonat (PC) mit einem Acryl-Kleber wurde mit einer thermodynamischen, auf der Messung von Oberflächenspannungen beruhenden Methode bestimmt.Die Charakterisierung der Oberflächen zeigte, daß eine Plasmabehandlung die Bildung einer sauerstoffreichen Oberflächenschicht bewirkt. Eine Lagerung in Wasser führt bei PP zu keiner Veränderung dieser Schicht, während bei PC niedermolekulare, oxidierte Verbindungen ausgewaschen werden.Sowohl unbehandelte als auch mit Plasma behandelte PP-Verbindungen wiesen bei Lagerung in Wasser eine annehmbare Stabilität auf. Zwar wurde eine geringe Abnahme der Scherfestigkeit gemessen, aber unbehandeltes und plasmabehandeltes PP zeigten weiterhin adhäsives bzw. kohäsives Bruchverhalten.Im Falle von PC blieben nur die aus unbehandeltem PC hergestellten Verbindungen ausreichend stabil, während die aus plasmabehandeltem PC hergestellten Verbindungen stark abgebaut wurden. Bei den letzteren wanderte der Versagensort an die Polymer/Kleber-Grenzfläche, was auf die Ausbildung einer sehr hydrophilen, niedermolekularen Schicht zurückgeführt wird.
    Notes: The stability of PP and PC/acrylic adhesive joints has been assessed using a thermodynamic method based on surface tension components.Surface characterization showed that plasma treatment induces the formation of an oxygen-rich layer on treated surfaces. In the case of PP this layer does not change its composition upon immersion in water, while for PC leaching of oxidized species with low molecular weight was observed.Both untreated and plasma treated PP joints showed reasonable stability against immersion in water. A small reduction of shear strength was observed, but the fracture remained adhesive for untreated PP and cohesive for plasma treated PP.In the case of PC, only joints made from untreated PC showed fair sensitivity against immersion in water, while those made from plasma treated specimens degraded dramatically. In the latter case the locus of failure moved to the adhesive/adherend interface, the presence of a very hydrophilic, low molecular weight layer being suggested as responsible for this behavior.
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  • 88
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The chloromethylated polystyrenes bearing tetrathiafulvalenylcarbonyloxymethyl groups can be oxidized. We have shown that ion radical salts are obtained from these polymers and carbon tetrabromide after irradiation with UV light. Charge transfer complexes were prepared by mixing these polymers and 2,3-dichloro-5,6-dicyanobenzoquinone. The possible presence of sulfoxides as a result of oxidation of some tetrathiafulvalene units could explain the difficulties we have observed to filter solutions of these polymers.
    Notes: Les polystyrènes chlorométhylés renfermant des radicaux tétrathiafulvalénylcarbonyloxyméthyles peuvent être oxydés. Ainsi la formation de sels d'ions radicaux obtenus à partir de ces polymères et de tétrabromure de carbone, irradiés sous UV, a été mise en évidence. Des complexes de transfert de charge ont été préparés en mettant en présence ces polymères et de la 2,3-dichloro-5,6-dicyanobenzoquinone. La présence de sulfoxydes non décelés et résultant de l'oxydation de certaines unités de tetrathiafulvalène contenus dans ces polymères pourrait expliquer les problèmes rencontrés lors de la filtration de leurs solutions.
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  • 89
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Metallkomplexierung von wasserloslichem Poly[1-(2-hydroxyethyl)aziridin-co-2-methyl-2-oxazolin] mit Co(II), Zn(II), Ni(II), Cu(II), Cr(III), Fe(III), Cd(II), Pb(II) und Sr(II)-Ionen wurde in wäßriger Phase mit der Methode der Liquid-Phase Polymer-Based Retention (LPR) untersucht. Die Studie zeigt, daß alle Metallionen, außer Co(II) und Zn(II), bei pH 5 komplexiert wurden. Im Gegensatz zu Sr(II), das nur eine schwache Wechselwirkung in einem pH-Bereich von 3 bis 7 zeigte, wurden bei pH 7 94% Co(II) und 88% Zn(II) retentiert. Bei pH 3 zeigten nur Cu(II) und Cr(III) eine Wechselwirkung mit dem Polymeren, wobei die Retentionswerte 76% für Cu(II) und 52% für Cr(III) betrugen. Viskositätsmessungen des Copolymeren in Gegenwart von Metallionen wurden bei verschiedenen pH-Werten durchgeführt.
    Notes: The metal complexation of water-soluble poly[1-(2-hydroxyethyl)aziridine-co-2-methyl-2-oxazoline] with Co(II), Zn(II), Ni(II), Cu(II), Cr(III), Fe(III), Cd(II), Pb(II), and Sr(II) ions was investigated in aqueous phase using Liquid-Phase Polymer-Based Retention (LPR). The study shows that all metal ions are complexed at pH 5, except Co(II) and Zn(II). In contrast to Sr(II), which showed only a slight interaction over a pH range of 3 to 7, 94% of Co(II) and 88% of Zn(II) were retained at pH 7. At pH 3, only Cu(II) and Cr(III) ions interacted with the copolymer with retention values of 76% for Cu(II) and 52% for Cr(III). Viscosimetric measurements of the copolymer were performed in the presence of metal ions at different pH values.
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  • 90
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 197 (1992), S. 117-129 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Makroretikulare Copolymerperlen wurden durch Suspensionspolymerisation von Styrol, Bis(2-chlorethyl)vinylphosphonat (CEVP) und Divinylbenzol (DVB) in Gegenwart von Toluol als Verdünnungsmittel hergestellt. Die auf der Perlenoberfläche vorhandenen 2-Chlorethylphosphonat-Gruppen wurden durch Hydrolyse mit verdünnter Salpetersäure in Phosphon-Gruppen transformiert. Für die Einführung zusätzlicher Phosphon-Gruppen wurden die Copolymeren in Gegenwart von Aluminiumchlorid-Katalysator mit Phosphortrichlorid phosphoryliert, und die dabei entstandenen Dichlorphosphingruppen wurden mit verdünnter Salpetersäure verseift und oxidiert. Die Untersuchungen zur Chelatbildung der Copolymeren mit Metallionen zeigten, daß sie ein hohes Adsorptionsvermögen für Uranylionen und gute Stabilität gegen Chemikalien wie Säuren und Alkalien aufweisen. Es wurde auch gefunden, daß die Phosphongruppen enthaltenden Copolymeren recht effektive Adsorbentien für eine Vielzahl von Schwermetalionen wie Pb2+, Hg2+, Cd2+ und Cu2+ sind.
    Notes: Macroreticular copolymer beads were prepared by suspension polymerization of styrene, bis(2-chloroethyl) vinyl phosphonate (CEVP) and divinylbenzene (DVB) in the presence of toluene as diluent. The bis(2-chloroethyl) phosphonate groups on the bead surface were converted into phosphono groups by hydrolysis with dilute nitric acid. For the additional enrichment of phosphono groups, the copolymers were phosphorylated at the phenyl rings with phosphorus trichloride in the presence of aluminum chloride and hydrolyzed and oxidized with dilute nitrics acid. The investigations on metal ion chelation characteristics of the bead-type copolymers revealed that they have very high adsorptivity toward uranyl ions and good chemical resistance under acidic and alkaline media. It was also found that the phosphono group-containing copolymer beads are effective adsorbents for other heavy metal ions such as Pb2+, Hg2+, Cd2+, and Cu2+.
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  • 91
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 197 (1992), S. 131-139 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Lösungen von Phenylisocyanat (I) in DMF wurden sowohl bei verschiedenen Temperaturen als auch in Gegenwart von Polyurethankatalysatoren und/oder 1,3-Diphenylharnstoff (II) gelagert. Die Reaktionsprodukte wurden mit Hilfe der HPLC quantifiziert. Neben der Hydrolyse von I zu II wird bei 20°C eine signifikante Reaktion von I mit II zu 1,3,5-Triphenylbiuret (III) beobachtet.Oberhalb 60°C reagiert I mit dem Lösungsmittel zu N,N-Dimethyl-N′-phenylformamidin (V). In DMF dissoziiert III bereits bei Temperaturen 〉 40°C zu I und II.
    Notes: Solutions of phenylisocyanate (I) in DMF were stored at different temperatures in the presence of both polyurethane catalysts and 1,3-diphenylurea (II). The reaction products were determined by HPLC. Beside the hydrolysis of I to II, a significant reaction of I with II to 1,3,5-triphenylbiuret (III) was observed at 20°C. Above 60°C, I reacted with the solvent to form N,N-dimethyl-N′-phenylformamidine (V). In DMF, III dissociated to I and II already at temperatures 〉40°C.
    Additional Material: 3 Ill.
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  • 92
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 197 (1992), S. 141-147 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Glasfaserverstärkte Epoxidlaminate wurden aus den Matrixharzen Tetraglycidyldiaminodiphenylmethan (TGDDM) und Tetraglycidylbis(o-toluidino)methan (TGMBT) unter Verwendung von Härtern wie 4,4′-Diaminodiphenylmethan (DDM), 4,4′-Diaminodiphenylsulfon (DDS) und Diethylentriamin (DETA) hergestellt. Die mechanischen und dielektrischen Eigenschaften sowie die Chemikalienresistenz der Laminate wurden untersucht. Die Zugabe eines Epoxyverstärkers (20 Gew.-%, bezogen auf das Matrixharz) ergab eine Verbesserung der mechanischen Eigenschaften.
    Notes: Glass fiber-reinforced epoxy composites were prepared from the matrix resins tetraglycidyl diaminodiphenylmethaneSystematic name: N,N,N′,N′-Tetrakis(2,3-epoxypropyl)-4,4′-diaminodiphenylmethane. (TGDDM) and tetraglycidyl bis(o-toluidino)-methaneSystematic name: N,N,N′,N′-Tetrakis(2,3-epoxypropyl)-4,4′-bis(o-toluidino)methane. (TGMBT) using various amines like 4,4′-diaminodiphenylmethane (DDM), 4,4′-diaminodiphenylsulfone (DDS) and diethylene triamine (DETA) as curing agents. The fabricated laminates were evaluated for their mechanical and dielectrical properties and chemical resistance. The composites prepared using an epoxy fortifier (20 phr) showed significant improvement in the mechanical properties.
    Additional Material: 3 Tab.
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  • 93
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 197 (1992), S. 149-157 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: In 1 μm layers of different polymers containing 10 wt.-% 4,4′-diazidobiphenyl, the network formation under the influence of UV-irradiation was estimated by solvent treatment. The high activity of poly(glycidyl methacrylate) against the nitrenes formed is caused by its 1,2-epoxypropyl groups. As confirmed by IR-spectroscopy, the oxirane ring itself is not affected; NMR spectroscopic results indicate reactions between nitrenes and exocyclic CH2-groups.
    Notes: Die UV-Vernetzung in 1 μm-Schichten aus Polymeren verschiedener Konstitution, die 10 Gew.-% 4,4′-Diazidobiphenyl (DABP) enthalten, wird zeitabhängig anhand der reduzierten Schichtdicke nach Lösungsmittelbehandlung verglichen. Für die hohe Vernetzungsgeschwindigkeit von Polyglycidylmethacrylat mit den photolytisch gebildeten Bisnitrenen sind die 1,2-Epoxypropylgruppen verantwortlich. Der Oxiranring bleibt erhalten (IR-Spektroskopie). Wahrscheinlicher Reaktionsort ist die exocyclische CH2-Gruppe (13C-Festkörper-NMR-Spektroskopie).
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 94
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 197 (1992), S. 159-173 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Ausgehend von 10 unterschiedlich 4′-substituierten 4-[N,N-dihydroxyethyl]aminoazobenzolen wurden durch Umsetzung mit Hexamethylendiisocyanat polymere Azofarbstoffe (M̄n 4200-10200) synthetisiert und die Substituentenabhängigkeit der spektralen Eigenschaften, der Redoxpotentiale und des Ausbleichverhaltens mit entsprechenden monomeren und dimeren Modellverbindungen verglichen. Die Ausbleichung erfolgt durch einen photooxidativen Prozeß. In der Reihenfolge monomerer 〉 dimerer 〉 polymerer Azofarbstoff sinkt die Lichtstabilität durch die Verringerung thermischer Desaktivierungsprozesse sowie durch einen möglichen intramolekularen Energietransfer.
    Notes: Starting from 10 different 4′-substituted 4-[N,N-dihydroxyethyl]aminoazobenzenes, polymeric urethane-azo dyes (M̄n 42000-10200) were prepared by reacting those with hexamethylene diisocyanate. The dependence of spectral properties, redox potentials and photofading behaviour on the kind of substitutents was determined and then compared with corresponding monomer and dimer model compounds. Photofading is caused by a photooxidative process. In the sequence of monomeric 〉 dimeric 〉 polymeric azo dyes, light stability decreases due to a diminution in thermal disactivation processes and in a possible intramolecular energy transfer.
    Additional Material: 3 Ill.
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  • 95
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 197 (1992), S. 207-208 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 96
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 197 (1992), S. 201-206 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Bead cellulose, particle diameter 0.1 - 2.7 mm, was prepared from dispersions of viscose in chlorobenzene by applying the thermal sol-gel transition. Technical viscose containing modifiers Berol Visco 32, Berol Glyco 1540 and Kordamin V was used. The size of cellulose beads can be controlled by means of the amount of oleic acid in the dispersion medium. The optimal result was reached at 5 - 6 mg oleic acid in 90 ml chlorobenzene.
    Additional Material: 2 Ill.
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  • 97
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 197 (1992), S. 185-199 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: PET- und PA 66-Textilien wurden unter normalen Bedingungen mit verschiedenen Dispersionsfarbstoffen gefärbt. Die gefärbten Textilien wurden mit 180 kV Elektronenstrahlung bestrahlt. Es wurde beobachtet, daß, verglichen mit den unbestrahlten Materialien, zunehmende Strahlungsdosen zu einer Zunahme des Gesamtfarbabstandes dE führten. Diese Farbunterschiede werden hauptsächlich von zwei Reaktionen verursacht: Erstens von der reversiblen Bildung von Farbstoffradikalen, die (an Luft) wieder zu den Ausgangsfarbstoffen reoxidiert werden können und zweitens durch die irreversible Reaktion von Farbstoffmolekülen mit dem Faserpolymeren. Die zweite Reaktion ruft eine permanente Farbänderung des Textils hervor, die bei entsprechenden Bestrahlungsbedingungen klein gehalten werden kann. Die Entscheidung, ob diese Veränderung toleriert werden kann, hängt von der weiteren Verwendung des Textils ab.
    Notes: PET and PA 66 fabrics were dyed with different disperse dyes under regular conditions. The dyed fabrics were irradiated with 180 kV electron radiation. It was observed that increasing radiation doses led to increasing total color differences dE if compared to the unirradiated materials.These color differences are mainly caused by two types of reactions. First by the reversible formation of dye radicals, which can be reoxidized (in air) to the original dye molecules, and second by the irreversible reaction of dye molecules with the fiber polymer. The latter reaction causes a permanent change of the color of the fabric, which can be kept low with the proper irradiation conditions. The decision whether or not this change can be tolerated depends on the further use of the textile.
    Additional Material: 12 Ill.
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  • 98
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 197 (1992), S. 175-184 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Unterschiedlich 4′-substituierte 4-[N-Ethyl-N-(2-acryloyloxy)ethyl]aminoazobenzole dienten als Ausgangsmonomere für Homopolymerisationen und Copolymerisationen mit Styrol und Methylmethacrylat. Die Photobleichung der erhaltenen polymeren Azofarbstoffe (M̄ 4200-9000) wurde mittels einer Xenotest-Apparatur untersucht und mit den entsprechenden Monomeren verglichen. Es wird angenommen, daß die in der Reihenfolge monomerer  -  copolymerisierter  -  homopolymerisierter Azofarbstoff sinkende Photostabilität durch zunehmenden Energietransfer in der Matrix verursacht wird.
    Notes: Different 4′-substituted 4-[N-ethyl-N-(2-acryloyloxy)ethyl]aminoazobenzenes were used as starting monomers for homopolymerization and copolymerization reactions with styrene and methyl methacrylate. The photofading behaviour of the obtained polymeric azo dyes (M̄n 4200 - 9000) was investigated by means of a Xenotest device and compared with that of the corresponding monomers. The decreased photostability in the order monomer  -  copolymer  -  homopolymer was assumed to be caused by an increasing energy transfer in the matrix.
    Additional Material: 2 Ill.
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  • 99
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 198 (1992), S. 31-38 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: N-Methacryloyloxyphthalimid und N-Methacryloyloxytetrabromphthalimid wurden durch Reaktion von Methacrylsäure bzw. Methacryloylchlorid mit N-Hydroxyphthalimid bzw. N-Hydroxytetrabromphthalimid hergestellt und homopolymerisiert. Die Austauschreaktionen der Polymeren mit Hydroxy- und Amin-Verbindungen wurden untersucht.
    Notes: N-Methacryloyloxyphthalimide (NMPI) and N-methacryloyloxytetrabromophthalimide (NMTPI) were prepared by the reaction of methacrylic acid with N-hydroxy-phthalimide and N-hydroxytetrabromophthalimide, respectively. The resulting monomers were polymerized. The reactions of the resulting polymers with hydroxy and amine compounds have been studied.
    Additional Material: 4 Tab.
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  • 100
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 198 (1992), S. 15-29 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Das Tempern von Poly(etheretherketonketon) zwischen Glasübergangs- und Schmelztemperatur erzeugt normalerweise einen ausgeprägten Doppelschmelzpeak in der DSC-Kurve dieses Polymeren. Die eingehende Untersuchung dieses Doppelschmelzverhaltens in Abhängigkeit von Temperbedingungen und experimentellen Parametern zeigt, daß die Kristallisation als ein in zwei Stufen mit unterschiedlichen Zeitskalen ablaufender Prozeß beschrieben werden kann. Eine Rekristallisation als Ursache des Doppelpeaks kann widerlegt werden.
    Notes: Annealing poly(ether ether ketone ketone) (PEEKK) between glass transition and melting temperature generally results in a pronounced double peak melting behavior as obtained by DSC. Detailed investigations of the dependence of this double peak melting behavior on annealing conditions and experimental parameters clearly reveal that the crystallization can be described by a two-stage process occurring on different time scales. A recrystallization model as origin for the double peak melting curves can be disproved.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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