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  • 1980-1984  (3,273)
  • 1960-1964
  • Physics  (2,657)
  • Rat  (616)
  • 101
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    Springer
    Journal of cancer research and clinical oncology 108 (1984), S. 114-120 
    ISSN: 1432-1335
    Keywords: Nasal cavities ; Rat ; DOPN
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Weekly SC administration of 2,2-dioxopropylnitosamine to 88 Sprague-Dawley rats resulted in the induction of 76 separate neoplasms in the respiratory region of the nasal cavities. No tumors of the olfactory region were found. Histologically there were 37 squamous papillomas, 17 transitional papillomas, and 22 squamous cell carcinomas. These tumors were compared with a selected group of 53 related human tumors of the nasal and paranasal cavities, consisting of 11 squamous cell papillomas, 13 transitional papillomas, and 29 squamous cell carcinomas. While the experimental squamous cell papillomas showed a striking histological resemblance with the squamous papillomas observed in man, none of the experimental transitional papillomas had evidence of the characteristics inverted pattern seen in humans: nevertheless, the experimental tumors showed signs of incomplete squamous metaplasia and preservation of intraepithelial secretory glands, features commonly seen in transitional papillomas of man. The squamous cell carcinomas of this experiment were very similar to the corresponding human tumors in morphology and sex incidence. In both species a significant number of squamous cell carcinomas were keretinizing and of a high grade of histological malignancy. In addition, 69% of the human squamous cell carcinomas occurred in the male sex, and 72% of the experimental carcinomas developed in males. This comparative study suggests that further studies investigating the significance of nitrosamines as suspected etiologic factors of nasal carcinogenesis in man may be useful.
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  • 102
    ISSN: 1432-2072
    Keywords: Diazepam ; Prenatal ; Early postnatal treatment ; Learning disabilities ; Hyperactivity ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In the present study we have investigated the effects of diazepam (DZP) (10 mg/kg) treatment of rat dams during different periods of gestation or during lactation on the development and behavior of their offspring. The results show that DZP exposure during different phases of early development has differing effects on later behavior. Exposure during mid-gestation resulted in early and transient hyperactivity, but no learning or memory deficits at 2 months of age were observed. However, both late prenatal and early postnatal exposure to DZP resulted in significant behavioral changes. Late prenatal treatment caused no hyperactivity but resulted in poor performance on the learning and retention of a choice discrimination task, while early postnatal exposure resulted in consistent and lasting hyperactivity and in substantial discrimination learning and retention deficits at 2 months of age.
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  • 103
    ISSN: 1432-2072
    Keywords: Ethanol ; Behaviourally augmented tolerance ; Physiological tolerance ; Muscarinic receptor ; Operant conditioning ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Two groups of adult male rats were injected daily with ethanol (1.5 g/kg IP in 15% w/v solution) either before (the behaviourally augmented tolerant group) or after (the physiologically tolerant group) being placed in operant chambers. The control groups received daily isotonic saline injections either before or after the operant task. When challenged with ethanol (2.5 g/kg) on day 30 prior to the operant task, the control group was most impaired, while the behaviourally augmented tolerant group was significantly less impaired than the physiologically tolerant group. The two ethanol-treated groups were impaired to the same extent when challenged on day 60. Partial generalization of this behavioural tolerance to ethanol was observed, as the behaviourally augmented tolerant group was less impaired than the physiologically tolerant group for a tail flick response to painful stimuli after an ethanol challenge on day 30. However, the two ethanol-treated groups exhibited similar impairments of locomotor activity after an ethanol challenge on day 40. No differences in muscarinic receptor binding among the control and two ethanol-treated groups were found. These findings demonstrate that behaviourally augmented tolerance to ethanol may be partially generalizable but is unrelated to changes in muscarinic cholinergic receptors.
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  • 104
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    Pflügers Archiv 401 (1984), S. 414-417 
    ISSN: 1432-2013
    Keywords: Brown adipose tissue ; Microspheres ; Noradrenaline ; Rat ; Regional blood flow ; Xenon clearance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The xenon clearance method was adapted to continuous measurement of interscapular brown adipose tissue (ISBAT) blood flow in anaesthetized rats. The ISBAT-blood partition coefficient for xenon was determined to 3.6 ml·g−1. The blood flow values obtained by Xe clearance were compared with flow values obtained concomitantly by the microsphere technique in 17 cold acclimated rats, at ISBAT blood flows between 0.1 and 6 ml·g−1·min−1. Variations in blood flows were obtained by infusion of noradrenaline at different rates. The blood flow values obtained from the xenon clearance method showed a close correlation to the blood flow values determined with microspheres.Y=0.98.X+0.15 (r=0.96,P〈0.001). The Xe clearance method has the advantages compared to the microsphere technique that it permits continuous monitoring of the blood flow and does not require the sacrifice of the animal.
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  • 105
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    Naunyn-Schmiedeberg's archives of pharmacology 326 (1984), S. 248-253 
    ISSN: 1432-1912
    Keywords: Neonatal capsaicin ; Antinociceptive effects ; Adjuvant arthritis ; Substance P ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Rats were treated with capsaicin (50 mg/kg, SC) either on the second day or on the second and third days of life. A significant attenuation of the responses to noxious stimuli was obtained in the capsaicin treated animals as measured by the hot-plate or paw pressure tests but not by the tail-flick test. Furthermore, neonatal capsaicin produced a significant reduction of response in the formalin test. Capsaicin reduced the reaction latency in rats with adjuvant arthritis as measured by the hot-plate and paw pressure tests, though capsaicin did not alter the overall time course of the response to Freund's adjuvant. Capsaicin also attenuated the weight loss or the decreased ambulatory and rearing behaviour which occurred in the control animals with adjuvant arthritis. It is suggested that neonatal treatment with capsaicin may relieve the responsiveness to longlasting nociceptive stimuli by adjuvant in rats.
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  • 106
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    Naunyn-Schmiedeberg's archives of pharmacology 326 (1984), S. 227-232 
    ISSN: 1432-1912
    Keywords: Pentobarbital ; Benzodiazepine derivatives ; Cerebellar Purkinje cell ; Interposed nucleus cell ; Discharge pattern ; Rabbit ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The discharge of cerebellar neurons was investigated in the rabbit and the rat under the influence of pentobarbital, diazepam or medazepam. In the rabbit, these drugs are known to induce a rhythm ranging between 4 and 25 Hz in the red nucleus (RN) and the cerebellum (Cb). Purkinje cells (P cells) in the intermediate zone of the cerebellar cortex as well as neurons of the interposed nucleus (IPN) were found to discharge with burst patterns fully synchronized with the drug-induced RN rhythm. In contrast, P cells in the medial cerebellar zone responded to these drugs only with changes in their discharge rate. Since P cells of the intermediate longitudinal zone project to the RN mainly via the IPN, the present findings complement our previous results, indicating that the rhythmic electrical activity in the RN is initiated by the cerebellum. The three drugs had similar effects on the activity of cerebellar units in the rabbit and the rat. The investigation also shows that, in spite of the uniform morphological structure of the cerebellar cortex, P cells do not respond uniformly to a given drug: the diversity of findings published on the P cell response to barbiturates or benzodiazepine derivatives may be explained by differences in the recording sites.
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  • 107
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    Naunyn-Schmiedeberg's archives of pharmacology 327 (1984), S. 14-17 
    ISSN: 1432-1912
    Keywords: Bethanechol ; Electromyogram ; Substantia nigra pars reticulata ; Morphine ; Muscular rigidity ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Bethanechol chloride (5–25 μg), when injected into the substantia nigra pars reticulata (SNR) of rats, produced muscular rigidity in a dose-dependent way, and in addition, catalepsy and ipsilateral posture. The effects of bethanechol in the dose of 25 μg were prevented by coadministration of 10 μg scopolamine hydrochloride. Injections of 25 μg betanechol or 10 μg scopolamine into the reticulata only slightly affected the muscular rigiditiy produced by 15 mg/kg i.p. morphine hydrochloride. The results suggest that muscarinic cholinergic mechanisms in the substantia nigra pars reticulata, although effective by themselves, affect by expression of at least one striatal functional alteration, the muscular rigidity, in a less effective way than GABAergic or endogenous opioid mechanisms do.
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  • 108
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    Cell & tissue research 236 (1984), S. 373-381 
    ISSN: 1432-0878
    Keywords: Merkel cell surface ; Quinacrine fluorescence ; Lectins ; Vibrissae ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Surface carbohydrates on the Merkel cell of the outer root sheath (ORS) were investigated in 1to 4-day-old rat vibrissae by use of rhodamine isothiocyanate (RITC)-conjugated lectins. The red fluorescence of RITC provided a convenient assay for lectin binding to the Merkel cell, which is itself identified by its green fluorescence following selective uptake of the dye quinacrine. In monolayers or suspensions of freshly dissociated ORS cells, the Merkel cell showed high affinity for the α-fucose-specific lectin, Ulex europeus agglutinin I (UEA-I), thus revealing a novel feature for a basally located cell. Other high-affinity lectins included concanavalin A (Con A), wheat germ agglutinin (WGA), soybean agglutinin (SBA), and Ricinus communis agglutinin I (RCA-I). In contrast, Dolichos biflorus (DBA), Bandeiraea simplicifolia I and II (BS-I and BS-II), and peanut agglutinin (PNA) virtually excluded the Merkel cell, though PNA-binding sites were unmasked after neuraminidase treatment. Other dispersed ORS cells had varying lectin affinities, and generally binding was inhibited by a competing haptenic sugar. The pattern of lectin binding seen in cryostat and paraffin sections of the vibrissa suggested that the Merkel cells share surface properties with their neighboring basal and/or spinous cells; however, unshared properties are likely to exist since ingrowing mechanosensory nerves recognize the Merkel cells, and not other epidermal cells, as their targets.
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  • 109
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    Cell & tissue research 236 (1984), S. 711-715 
    ISSN: 1432-0878
    Keywords: Gastric antral mucosa ; Caerulein ; Gastrointestinal hormones ; Cholecystokinin ; Trophic effect ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The growth-promoting effect of caerulein on antral gastric mucosa was explored using Wistar rats. Implanted osmotic minipumps were used to administer submaximal doses of either caerulein or saline to normal rats for up to 4 days. In one group, reflux of bile and pancreatic juice into the stomach was avoided by previous surgical diversion of the distal common bile duct to the jejunum. DNA synthetic and mitotic activity in the antrum epithelium were estimated by 3H-thymidine pulse labelling and autoradiography during the administration of the peptide. The rate of cell migration was determined in animals killed 1, 2 and 3 days after the 3H-thymidine pulse. Administration of caerulein to normal rats provoked significant increases in both labelling and mitotic indices, and a significant acceleration of the upward cell migration in the glandular tubes. In the animals with distal diversion of bile and pancreatic secretions both labelling and mitotic indices were also increased over control values under the effect of the peptide. These data indicate that administration of caerulein stimulates cell proliferation in the antral gastric mucosa. This effect cannot be explained through increased reflux of pancreaticobiliary secretions in the stomach.
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  • 110
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    Cell & tissue research 236 (1984), S. 699-709 
    ISSN: 1432-0878
    Keywords: Testis ; Spermatogenic cycle ; Sertoli cell ; Lipid ; Morphometry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The volume and surface area of lipid inclusions often present in the cytoplasm of rat Sertoli cells was measured directly from semi-thin sections of perfusion-fixed testicular tissues using an image analyser linked to a light microscope. Sertoli cell nuclei were used as a reference for comparing any variations in the measured parameters of lipid inclusions during the rat spermatogenic cycle. Volume density of Sertoli cell lipid inclusions was assessed by morphometric analysis of Sertoli cells photographically reconstructed from electron micrographs. Maximum lipid content in Sertoli cells occurred during stages IX–XIV of the spermatogenic cycle, then declined at stages I–III and remained low from stages IV–VIII. The persistence and increase in number of many large Sertoli cell lipid inclusions beyond the stage where spermatid residual bodies are phagocytosed within the Sertoli cells (stage IX) suggests that the synthesis and lipolysis of Sertoli cell lipid inclusions represents an intrinsic functional cycle of the Sertoli cells. Stage-dependent variations in the lipid content of rat Sertoli cells offers morphological evidence that the metabolic duties of the Sertoli cells are synchronised with the spermatogenic cycle to provide local coordination of the proliferation and maturation of the germ cells.
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  • 111
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    Cell & tissue research 236 (1984), S. 717-724 
    ISSN: 1432-0878
    Keywords: Ovary ; Ovarian follicle ; Atresia ; Immunoregulation ; Immune tolerance ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Thy-1+ cells, producing Thy-1+ material, have been demonstrated by the indirect immunoperoxidase technique in the theca of growing ovarian follicles of the rat. OX-2 antigen, known as the minor glycoprotein of rat thymocytes, was detected in granulosa cells of non-growing follicles. Ia+ cells of dendritic type and/or activated macrophages were identified in the granulosa of advanced degenerating follicles, and remnants of the zona pellucida exhibited immunoglobulins. In some ovaries immunoglobulins were also bound to the zona pellucida of oocytes of early degenerating antral follicles. Medium-sized antral follicles with degenerating granulosa were occasionally invaded by cells carrying antigens of cytotoxic T lymphocytes or other T lymphocyte subsets, while degenerating large antral follicles were sometimes invaded by cells exhibiting antigen of cells with natural killer function (but not antigens of T lymphocytes). Granulosa cells of some degenerating antral follicles exhibited class-I antigens derived from the major histocompatibility complex. We suggest that cell-mediated control mechanisms of antigen expression and metabolism of tissue cells during their differentiation and degeneration should be considered in addition to the well-documented hormonal dependence of some tissues.
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  • 112
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    Cell & tissue research 237 (1984), S. 245-252 
    ISSN: 1432-0878
    Keywords: Pineal organ ; Interstitial cells ; Astrocytes ; Immunocytochemistry ; Rat ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Antigenic markers characteristic of astrocytes and their differentiative states (i.e., glial fibrillary acidic protein (GFAP), vimentin, and M1 and C1 antigens) were investigated in the pineal gland of mouse and rat using double immunolabeling techniques. In both species the socalled interstitial cells as characterized by TEM were shown to be astrocytes, since they expressed vimentin, but neither fibronectin (a marker for fibroblasts and endothelial cells) nor the neuron-specific L1 antigen or tetanus toxin receptors. Subpopulations of vimentin-positive pineal astrocytes were also GFAP- and C1- antigen-positive. M1- antigenpositive cells were not detected. It is concluded that a considerable proportion of interstitial cells in the pineal gland of rat and mouse are immature astrocytes which, in contrast to other parts of the central nervous system, persist into adulthood.
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  • 113
    ISSN: 1432-0878
    Keywords: Thyroid gland, fetal ; Cytoskeleton ; Cytocha lasin B ; Vinblastine ; Colchicine ; Follicular development (thyroid) ; Tissue culture ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Thyrotropic hormone (TSH) or cAMP accelerate the formation of follicular cavities in the explanted thyroid gland of the 15-day-old rat fetus. Cytochalasin B or vinblastine and nocodazole or colchicine, which disorganize microfilamental and microtubular structures respectively, inhibit or completely block in vitro-induced folliculogenesis. Exposure of the thyroid tissue to lumicolchicine, a structural isomer of colchicine deprived of antimicrotubular activity, does not inhibit the activation of folliculogenesis induced by TSH. These results are strong evidence for the supposition that microfilaments and microtubules are involved in the TSH-stimulated mechanisms resulting in thyroid folliculogenesis. Folliculogenesis requires the integrity of both microfilaments and microtubules.
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  • 114
    ISSN: 1432-0878
    Keywords: CRF-neurons ; Hypothalamus ; Development, ontogenetic ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Appearance of immunoreactive corticotropin-releasing factor (CRF)-containing neurons was studied in developing hypothalamus of the rat by use of antisera against rat- and ovine CRF. These neurons were first recognized in the lateral and paraventricular nuclei on days 15.5 and 16.5 of gestation, respectively, when antiserum against rat CRF was employed. Antiserum against ovine CRF revealed the cells two days later exclusively in the latter nucleus. In both nuclei, the neurons increased in number with development. The neurons in the paraventricular nucleus appeared to project their immunoreactive processes to the median eminence via the periventricular and lateral pathways. In the median eminence, the immunoreaction with antiserum to rat CRF was first recognized in its anterior portion in the form of dots on day 16.5 of gestation but as beaded fibers in the external layer on day 17.5; these structures increased in amount with development in rostro-caudal direction. Although antiserum to ovine CRF was less potent in immunostainability than antiserum to rat CRF, it also revealed the beaded fibers in the median eminence on day 17.5 of gestation. Since evidence is available that the paraventricular nucleus is involved in corticotropin release, it is concluded that, in rats, the hypothalamic regulatory mechanism controlling the release of corticotropin initially appears on days 16.5–17.5 of gestation.
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  • 115
    ISSN: 1432-0878
    Keywords: Caldesmon ; Actin ; Immunocytochemistry ; Small intestine ; Smooth muscle ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of caldesmon (a calmodulin-binding, F-actin-interacting protein) (Sobue et al. 1982) and of actin was studied in the rat's small intestine by means of light-microscopic immunocytochemistry. Positive immunostaining for caldesmon was seen in smooth muscle cells of the intestinal wall, and of blood vessels, and in the apical portion of the absorptive epithelial cells. The immunoreactivity in goblet cells was difficult to recognize. The positive reaction to immunostaining for actin showed almost the same pattern as that for caldesmon. These results suggest that this calmodulin-binding protein may play an important role in the control of actin-myosin interaction in smooth muscle cells and in non-muscle cells.
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  • 116
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    Cell & tissue research 235 (1984), S. 433-438 
    ISSN: 1432-0878
    Keywords: Mammary gland ; Ferritin-concanavalin A ; Concanavalin A ; Endocytosis ; Membrane reuse ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ferritin-concanavalin A (Fer-Con A) was used to label the apical plasma membrane of the lactating cell to determine whether membrane internalization takes place. Rat glands were infused in vivo via the teat with 0.2 mg of Fer-Con A in 0.2 ml tris buffer (pH 7.0) containing 0.1% trypan blue, the latter acting as a marker of the infusate. Tissues were obtained from separate animals 5, 10 and 60 min postinfusion. Fer-Con A was seen in alveolar lumina bound to the outer surfaces of apical plasma membrane, microvilli and milk fat globules. It was observed within lactating cells on the inner membrane surfaces of endocytotic vesicles, Golgi cisternae, and secretory vesicles containing casein micelles, and in multivesicular bodies and lysosomes. Internalization of the ferritin-lectin conjugate into casein-containing secretory vesicles was detectable in the 5-min postinfusion tissue. Lysosomes were the only structures in control tissue that contained particles bearing some resemblance to Fer-Con A. The data provide evidence that apical plasma membrane is internalized and distributed to a number of intracellular compartments.
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  • 117
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    Cell & tissue research 235 (1984), S. 449-452 
    ISSN: 1432-0878
    Keywords: Suprachiasmatic nucleus ; Morphometry ; Synapses ; Sexual dimorphism ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The suprachiasmatic nucleus (SCN) of male rats was estimated to contain 16×106 synaptic appositions (unilaterally) or 250×106 appositions in 1 mm3 tissue of the nucleus with an average of 1404 appositions per neuron. There are significantly fewer synaptic appositions in the suprachiasmatic nucleus of female rats (15×106 per SCN or 236×106 in 1 mm3 tissue of SCN with 1264 appositions per neuron on an average). Additionally, numbers of various types of synapses (axo-somatic, invaginated, dendrodendritic and optic) are estimated.
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  • 118
    ISSN: 1432-0878
    Keywords: Monosodium-1-glutamate ; Neuropathology ; Rat ; Superior colliculus ; Toxicology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Systemic administration of monosodium-1-gluta-mate by single injections of 4 mg/g body weight in infant rats (2–10 days of age) results in acute swelling of cytoplasm and nuclear pyknosis of neurons in the stratum zonale and stratum griseum superficiale of the superior colliculus. Multiple daily doses of 4 mg/g body weight monosodium-1-glutamate result in an almost complete loss of neurons in these two superficial layers. The deeper layers appear not to be affected. No pathological effects were observed in the lateral geniculate body or pretectal complex. Light-and electron-microscopic studies reveal that the optic nerves are remarkably shrunken and many myelinated as well as unmyelinated axons are lost. Injection of 3Hproline into the vitreous body of one eye results in limited transport to the suprachiasmatic nucleus, lateral geniculate body and to lateral portions of the superior colliculus. The small percentage of intact axons in the optic nerve, as well as the limited proline transport from the eye, suggest that administration of monosodium-1-glutamate leaves intact some optic fibers, a portion of which belongs to the retinohypothalamic tract.
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  • 119
    ISSN: 1432-0878
    Keywords: Exocrine pancreas ; Calcium pool ; Calcium release ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In an attempt to identify a cellular Ca2+-pool, from which calcium is released when secretagogues are applied, tissue fragments of the rat exocrine pancreas were incubated and fixed with glutaraldehyde in the presence of calcium. By means of this procedure electron-dense deposits were found on plasma membranes. X-ray microanalysis showed that these deposits contain calcium. Stimulation of tissue fragments with the use of the secretagogues carbachol or cholecystokinin reduced the number of deposits by about 80%. When the antagonist atropine was applied after carbachol stimulation, deposits reappeared on cell membranes, which then disappeared again after a second stimulation with cholecystokinin. In the presence of procaine, carbachol was inhibited and only slightly reduced the Ca2+-deposits on the plasma membranes. These results suggest that a calcium pool, from which calcium is released to induce enzyme secretion on stimulation, is located in the cell membrane
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  • 120
    ISSN: 1432-0878
    Keywords: Somatostatin ; Ontogenesis ; Electron-microscopic immunohistochemistry ; Median eminence ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development of immunoreactive (ir) somatostatin-containing nerve terminals in the rat median eminence (ME) has been examined electron-microscopically. Nerve fibers containing ir particles scattered throughout the axoplasm are first seen in the external layer of the ME on day 18.5 of gestation, and, on day 21.5 appear to terminate on the basement membrane of the perivascular space of the portal vessels. After birth, the fiber terminals contain several membrane-limited granules, which are labeled with ir PAP particles. Ultrathin, Epon-embedded sections of ME, treated by the protein A gold-labeling method for somatostatin, demonstrate positively labeled granules in the nerve fibers in the postnatal ME, but in the prenatal tissue, no specific gold-labeling is found. These findings show that, in the external layer of the ME, somatostatin storing occurs in the granules in the axonal terminals after birth.
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  • 121
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    Cell & tissue research 236 (1984), S. 491-493 
    ISSN: 1432-0878
    Keywords: Brain vessels ; Basal lamina ; Pericytes ; Endothelial cells ; Glial cells ; Argyrophilic staining ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Vibratome sections obtained from perfusion-fixed rat brains were stained by means of silver impregnation and physical development according to Gailyas (1970). Small pieces of the cerebral cortex were postfixed with buffered osmium tetroxide solution and processed for electron microscopy to examine the localization of the silver deposit at the cellular level. The cell surfaces of pericytes and smooth muscle cells were completely outlined by silver grains. Endothelial cells and perivascular astrocytes, however, showed an asymmetric distribution of the silver deposit, i.e., the deposit was restricted to the abluminal endothelial surface and to the astrocytic membrane adjacent to the vessel wall, respectively. The method allowed a clear-cut distinction between perikarya of endothelial cells and pericytes as well as glial cells in perivascular position, even at the light-microscopic level.
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  • 122
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    Cell & tissue research 236 (1984), S. 249-255 
    ISSN: 1432-0878
    Keywords: Oocyte ; Nucleolus ; Silver staining ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The nucleoli of dictyate-stage growing oocytes in rat ovaries were examined both with routine electron microscopy and electron microscopy after silver nitrate and ammoniacal silver nitrate (Ag-AS) staining. The nucleoli of the unilaminar follicular oocytes consist of twisted strands of dense fibrillar components, aggregates of granular components, and small fibrillar centers. After Ag-AS staining, silver grains are numerous on the dense fibrillar strands, fewer on the fibrillar centers, and very sporadic on the granular aggregates. The same stainability of three nucleolar components with the Ag-AS method was also confirmed in the nucleoli segregated by actinomycin D. During the transition of growing oocytes from bilaminar to plurilaminar follicle stage, the nucleolar dense fibrillar strands gradually conglomerate and are transformed into large and compact spherules. The stainability of dense fibrillar components with the Ag-AS method was lost along with this nucleolar transformation. These results may provide some new clues on the functional significance of AgAS-positive proteins in the nucleoli.
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  • 123
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    Cell & tissue research 237 (1984), S. 103-109 
    ISSN: 1432-0878
    Keywords: Synapses ; Synaptogenesis ; Development fetal ; Olfactory cortex ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron microscopy was used to study synaptogenesis in prepyriform cortex of fetal rat pups during early stages of synapse formation. Of special interest is the frequent occurrence of unapposed, developing synaptic specializations in axon and growth cone profiles. The location and morphology of the unapposed specializations suggests that thay are presynaptic in nature. These presumably immature presynaptic specializations are found in the lateral olfactory tract and subjacent cortex. Intermediate forms between uncontacted presynaptic specializations and definitive synapses suggest a synaptogenic sequence in which initial development of an immature presynaptic specialization begins without apposition of a postsynaptic element at that location. This implies that initiation of presynaptic development is not dependent upon postsynaptic contact and also raises the question of whether synaptic contacts could be established via presynaptic induction of postsynaptic formation.
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  • 124
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    Cell & tissue research 237 (1984), S. 185-186 
    ISSN: 1432-0878
    Keywords: Gap junction ; Cytoskeleton ; Heart ; Ultrarapid freezing ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using ultrarapid-freezing techniques and freezefracture electron microscopy, we report here a close association between cardiac gap junctions and specialized membrane domains containing regularly-spaced furrows. These specialized furrowed domains are observed only during periods of gap junction re-organisation (i.e., connexon redistribution) and may reflect the presence of underlying cytoskeletal elements controlling the position of connexons in the membrane.
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  • 125
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    Cell & tissue research 237 (1984), S. 371-373 
    ISSN: 1432-0878
    Keywords: Endothelium ; Transport, intracellular ; Transport vesicles, channels ; Micropinocytosis ; Capillaries ; Endometrium ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Three types of transendothelial channels are described in the endothelium of blood capillaries in the endometrium of the rat. It is postulated that they may function as pores draining interstitial fluid to the venous blood.
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  • 126
    ISSN: 1432-0878
    Keywords: Thyroid ; Immunocytochemistry ; Caldesmon ; Actin ; Endocytosis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of caldesmon (a calmodulin-binding, F-actin interacting protein; Sobue et al. 1982) and actin was studied in the rat thyroid gland by means of light-microscopic immunocytochemistry, and the fine-structural distribution of actin filaments was examined by use of heavy meromyosin (HMM). Caldesmon and actin were demonstrated in the apical cytoplasm of almost all the follicle epithelial cells in normal as well as TSH-treated animals. Immunoreactivities for both caldesmon and actin showed almost the same pattern in localization. The smooth muscle cells of the blood vessels were also positive for caldesmon and actin. By electron microscopy, numerous actin filaments decorated by HMM and running perpendicularly or randomly to the apical surface were recognized in the apical cytoplasm of the follicle epithelial cell. These results suggest that caldesmon and actin, in conjugation with calmodulin, play a role in the regulation of cellular activity such as exocytosis and endocytosis in the apical portion of the follicle epithelial cell.
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  • 127
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    Cell & tissue research 235 (1984), S. 187-194 
    ISSN: 1432-0878
    Keywords: Golgi apparatus ; Monensin ; Small intestine ; Cytochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effect of short-time treatment with the ionophore monensin, administered intraluminally at concentrations of 5 and 10 μM, was studied on the Golgi apparatus of absorptive cells in the small intestine of the rat. At 2–3 min after treatment most of the Golgi stacks exhibited dilated cisternae. At 4–5 min stacked cisternae were absent; they were replaced by groups of smooth-surfaced vacuoles. Dilatation and vacuolization occurred in the entire stacks without preferential effect on any particular Golgi subcompartment. Monensin did not influence the cytochemical Golgi reaction of thiamine pyrophosphatase and acid phosphatase. The characteristic staining pattern of these two enzymes in all Golgi cisternae of absorptive cells in the proximal small intestine, and the reactivity restricted to trans cisternae in distal segments of the small intestine, were unchanged after treatment with monensin. In the distal small intestine, the cytochemical pattern allowed the monensin-induced vacuoles to be attributed to the former cisor trans-Golgi face. Further, the cytochemical results demonstrate that vacuolization is not restricted to the stacked cisternae, but includes the trans-most cisterna. The latter, usually located at some distance from the Golgi stacks, has been defined as belonging to the GERL system in several types of cells. The clear response to monensin, an agent that selectively affects the Golgi apparatus, indicates common properties between trans-most and stacked Golgi cisternae.
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  • 128
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    Cell & tissue research 235 (1984), S. 485-489 
    ISSN: 1432-0878
    Keywords: Ventromedial nucleus ; Hypothalamus ; Ultra-structure ; Nucleoli ; Estrogen effects ; Chromatin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Estrogen is accumulated from the blood by nerve cells in the ventromedial nucleus of the hypothalamus and can facilitate female reproductive behavior by acting on this region of the brain. This cell group was examined in ovariectomized female rats, given estrogen or control treatment, by use of light and electron microscopy. A significantly greater portion of the nerve cells in the estrogen-treated animals had protuberances on their nucleolar surfaces, apparent under the light microscope. The fine structure of such protuberances included dense, aggregated material, which is shown to contain DNA by the sodium tungstate staining technique. Because increased numbers of such protuberances were found in nuclei of cells of the experimental group where previous studies demonstrated a significant increase in ultrastructural signs of biosynthetic activity, they may be associated with increased RNA synthesis. Thus, they could indicate, ultrastructurally, increased synthetic rates for RNA in nerve cells through which estrogen promotes reproductive behavior.
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  • 129
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    Cell & tissue research 235 (1984), S. 669-673 
    ISSN: 1432-0878
    Keywords: Liver-cell heterogeneity ; Hepatic venous branches ; Karyometry ; Binucleate cells ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In untreated adult male albino rats nuclear volume and the percentage of binucleate cells were determined in the first layer of hepatocytes adjacent to hepatic venous branches of varying diameters (〈40 μm, 40 μm–80 μm, 80 μm–120μm, 120 μm–160 μm, 〉160 μm), and in the third and fourth layer of hepatocytes in the remainder of the perivenous parenchyma. In the first layer of hepatocytes adjacent to the vascular structures means of nuclear volume are significantly lower and percentage of binucleate cells significantly higher than in the cells of the remainder of the perivenous parenchyma. Within each area measured distribution curves of nuclear volume classes were homogeneous but showed heterogeneity in comparison with each other. The morphometric data presented in this study strongly support the opinion of the heterogeneity of liver cells in the perivenous zone, as previously postulated on the basis of histochemical investigations.
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  • 130
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    Cell & tissue research 236 (1984), S. 305-315 
    ISSN: 1432-0878
    Keywords: Hepatocytes ; Rat ; Liver ; Circadian rhythm ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Subcellular structures of hepatocytes in periportal and perivenous zones were examined during 24 h. The volume, surface and numerical profile densities of cytoplasmic organelles were analysed morphometrically. Most subcellular structures in periportal and perivenous hepatocytes were subject to strong circadian variations. In hepatocytes from both zones, the volume densities of smooth endoplasmic reticulum (sER), mitochondria, lysosomes, peroxisomes, polysomes and lipid droplets demonstrated peak values at 16.00 h, 20.00 h or 00.00 h; trough values were at 04.00 h, 08.00 h, or 12.00 h, except for peroxisomes (16.00 h). However, the volume densities of glycogen granules and rough endoplasmic reticulum (rER) in periportal and perivenous hepatocytes exhibited maximal values at 04.00 h, 08.00 h or 12.00 h and minimal values at 20.00 h. The surface densities of sER, mitochondria, lysosomes and peroxisomes, and the numerical profile densities of mitochondria, lysosomes and peroxisomes in periportal and perivenous hepatocytes showed similar trends. These events suggest that membranes of the rER show a partial correlation with the sER, mitochondrial and lysosomal membranes during the 24-h span. This may involve the interaction between ribosomes and rER. Almost all cytoplasmic organelles examined displayed significant differences between periportal and perivenous hepatocytes, morphometrically and in fine structure, indicating that the morphofunctional variability of hepatocytes differs depending on the location in the liver acinus.
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  • 131
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    Cell & tissue research 236 (1984), S. 321-325 
    ISSN: 1432-0878
    Keywords: Triiodothyronine ; Radioautography ; Mitochondria ; Liver ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary To assess the distribution of the thyroid hormone triiodothyronine (T3) within intact living cells, freshly prepared dispersed rat hepatocytes were incubated with [125I]-T3 for periods of 5 min and 30 min. Lightand electron-microscopic (EM) radioautography was carried out to determine the distribution of grains over the isolated cells. Both procedures showed the grains distributed almost entirely over the cytoplasmic matrix rather than the nucleus. Grain counts under the EM were compared with expectation based on established quantitative methods. Only the mitochondria showed obvious and statistically significant grain counts, whereas the nucleus failed to accumulate grains in excess of expectations by chance alone based on area. The findings support the existence of mitochondrial binding of T3, presumably a prerequisite for its action in direct stimulation of the mitochondria.
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  • 132
    ISSN: 1432-0878
    Keywords: Lymph node ; Steroids ; Macrophages ; Intercellular junctions ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Intercellular junctions were often found between macrophages in sinuses of regional lymph nodes of the rat after injection of large doses of cholesterol, cortisone acetate, and estrone at the footpad. They were identified by subplasmalemmal densities, 20–50 nm in width, beneath the plasma membranes of apposed macrophages. No distinct filamentous structures were visible in those dense regions. Electron-dense amorphous materials are lined up at the center of the intercellular space in the junctional regions. Some macrophages form clusters with intercellular junctions. No significant difference in the effect of cholesterol, cortisone acetate, and estrone on the number of intercellular junctions betwene macrophages was found.
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  • 133
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    Cell & tissue research 236 (1984), S. 171-180 
    ISSN: 1432-0878
    Keywords: Immunocytochemistry ; Ultrastructure ; Supraoptic nucleus ; Neuropil ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The neuropil located ventral to the SON was investigated by the use of immunoperoxidase staining for neurophysins, oxytocin and vasopressin, and electron miroscopy. The study was performed in six groups of rats: 1) control; 2) infusion of isotonic saline into the CSF; 3) infusion of hypertonic saline into the CSF; 4) drinking hypertonic saline for 4 days; 5) same as group 4 but injection of colchicine into the CSF on second day of dehydration; 6) salt loading for 3 months. In the control rats the ventral neuropil contained a few immunoreactive processes, the general morphology of which was completely different from that of the neurosecretory axons emerging from the SON at its dorsal aspect. In rats of groups 3 to 6 the ventral processes (VP) became loaded with neurosecretory granules, whereas the perikarya and axons were depleted. Based on their general morphology and reactivity pattern it is suggested that the VP are dendrites. Most of these “dendrites” were embedded in a glial cushion formed by the processes of a particular type of marginal glia. Some of these “dendrites” enveloped an arteriole penetrating the optic tract. All VP were rich in synaptic contacts. The possibility that the VP of neurosecretory cells may be functionally related to the subarachnoid CSF and the arteriolar blood flow is discussed.
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  • 134
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    Cell & tissue research 236 (1984), S. 561-566 
    ISSN: 1432-0878
    Keywords: Pituitary gland, pars intermedia ; Peptide hormones ; Dopamine ; Corticotropin-releasing hormone ; 6-Hydroxydopamine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary When rats were injected with 6-hydroxydopamine the catecholaminergic nerve terminals in their intermediate lobes exhibited distinct signs of degeneration. Morphometric examination of the Golgi apparatus in cells of the intermediate lobe of these rats showed significant enlargement of Golgi cisternae. The release of adrenocorticotropin, β-endorphin/lipotropin and α-melanotropin from intermediate-lobe cells in vitro was measured by radioimmunoassay. The high basal peptide release was inhibited by dopamine and stimulated by methyl-isobutyl-xanthine. In contrast, γ-aminobutyric acid, serotonin, histamine and noradrenaline, or corticotropin-releasing hormone, rat hypothalamic extract and vasopressin had no or only very weak effects. These observations indicate that the synthetic apparatus of intermediate-lobe cells is constantly depressed by dopaminergic nerves. We were not able to stimulate peptide release from intermediate-lobe cells by use of the abovementioned endogenous agents.
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  • 135
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    Cell & tissue research 237 (1984), S. 169-179 
    ISSN: 1432-0878
    Keywords: Foetal pancreas ; β Cells ; Insulin ; Fasting mothers ; Morphometry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary After maternal fasting for 72 h the pancreatic β cells of 18-day-old foetal rats show a conspicuous enrichment in secretory material, with an increase of pancreatic insulin concentration and a marked development of the rough endoplasmic reticulum and the Golgi apparatus. The morphometric analysis shows that the intracytoplasmic migration of the secretory granules is inhibited, principally inside the cell web. Consequently the number of secretory granules fused with plasma membrane decreases and this is associated with a decreased foetal plasma insulin. The difference in the ultrastructural aspect of the β cells of foetuses from fasting mothers and of foetuses from fed mothers is less conspicuous at 19 days of gestation and progressively disappears at 20 and 21 days. The modifications in ultrastructural aspect and in functional state are discussed.
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  • 136
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    Cell & tissue research 238 (1984), S. 81-85 
    ISSN: 1432-0878
    Keywords: Retina ; Ibotenic acid ; Toxicity ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary After 2 h intraocular injections of 19 and 190 nmoles ibotenic acid in the rat retina produced an intensive vacuolization of the inner plexiform layer and cellular alterations, in the inner nuclear layer and ganglion cell layer. These alterations consisted of either cytoplasmic swelling accompanied by clumping of the nuclear chromatin or darkening of the cytoplasm along with nuclear condensation. A week later the retinas were thinner than the controls due to the disappearance of the affected cells. Pre-treatment with diazepam prevents the morphological alterations induced by 19 nmoles ibotenic acid; mainly the swelling, which was completely prevented, while the darkening was reduced drastically, although some vacuolization of the inner plexiform layer is still present.
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  • 137
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    Cell & tissue research 238 (1984), S. 159-163 
    ISSN: 1432-0878
    Keywords: Ovary ; Rat ; Cell division ; Luteinizing hormone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effect of an LH pulse on the rate at which 3H-thymidine is incorporated into cultured ovaries of metestrous rats was studied. In comparison to ovaries cultured with tonic LH, an LH pulse (1) “rescued” follicles from atresia, (2) induced thecal cell proliferation, and (3) increased the rate at which granulosa cells enter mitosis. It is concluded that LH pulses increase follicular growth by first triggering thecal cell proliferation and then inducing mitotic divisions within the granulosa cells of both atretic and non-atretic follicles.
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  • 138
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    Keywords: Choroid plexus ; Immunoglobulin G ; Permeability ; Anti-HRP-IgG ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The localization of autologous antiperoxidase immunoglobulin G (IgG) was studied in the choroid plexus of Lewis rats immunized against horseradish peroxidase (HRP). This experiment was performed to study the permeability of the choroid plexus to intravascular IgG. It was shown that autologous IgG was present in the extravascular spaces. The transendothelial transfer appeared to occur mainly via the fenestrations and some interendothelial junctions. No transfer of IgG at the level of epithelial cells toward the cerebrospinal fluid was demonstrated. Interstitial spaces in contact with the connective-tissue cells of the choroid stroma were strongly labeled. The significance of these spaces remains hypothetical and raises the question of the fate of IgG from the interstitial space.
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  • 139
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    Cell & tissue research 238 (1984), S. 191-195 
    ISSN: 1432-0878
    Keywords: Glial fibrillary acidic protein (GFAP) ; Pituicytes, neonatal ; Development, ontogenetic ; Immunofluorescence ; Organ culture ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The appearance and intracellular localisation of glial fibrillary acidic protein (GFAP) in pituicytes in neural lobe cultures of newborn rats aged 7 to 30 days were investigated by use of the indirect immunofluorescence method. GFAP-immunoreactive cells were observed mostly in the outgrowth zone. GFAP was localised in the perikaryal cytoplasm as well as in pituicyte processes. GFAP-positive pituicytes showed considerable morphological polymorphism. The presence of GFAP — astrocytic marker — in pituicytes in vitro and the evident morphological similarity to cultured astrocytes suggest the astroglial character of these cells.
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  • 140
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    Keywords: Cyclic guanosine monophosphate-phosphodiesterase (cGMP-PDEase) ; New cytochemical method ; Retina ; Rods, outer segments ; Light perception ; 5′GMPase ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cyclic guanosine monophosphate-phosphodiesterase (cGMP-PDEase) activity was studied histo- and cytochemically in the retinal rods of the rat with the use of a newly developed technique. Intense activity of cGMP-PDEase was evenly distributed over the outer segments of the rods. Reaction product was observed on the plasmalemma and on the disk membranes of the outer segments. A weak reaction product occurred also on the plasmalemma of the inner segments; however, no precipitate was found in the perinuclear and synaptic portions of the rod cells. The enzyme activity was strongly inhibited by 2 mM theophilline and by 2 mM 3-isobutyl-1-methylxanthine (IBMX). To confirm the specificity of this new cGMP-PDEase method, the localization of 5′nucleotidase (5′GMPase) was also studied. In contrast to the activity of cGMP-PDEase, the activity of 5′GMPase was distributed on the plasma membrane of the photoreceptor cells extending over a wide range from the synaptic endings in the outer plexiform layer to the tip of the outer segments.
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  • 141
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    Keywords: S-100 ; Müller cell ; Astrocyte ; Development ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The rat retina was studied by immunohistochemistry with antibody to S-100 protein during the first three postnatal weeks. Immunoreactive astrocytes are first detected subjacent to the inner limiting membrane close to the optic disc. They gradually increase in number and spread toward the ora serrata along the inner surface of the retina as the development proceeds. S-100-immunostained Müller cells are first identified on the 12th postnatal day although their immunoreactivity is much weaker than that of astrocytes at the same stage. This differential intensity of the immunoreactivity of the two cell types facilitates observation of the entire shape of the astrocyte. This characteristic reveals that cellular investments of blood vessels in the inner retina are formed by astrocytic processes whereas those in the outer plexiform layer are derived from processes of Müller cells. The cellular investment becomes complete by the 18th postnatal day.
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  • 142
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    Cell & tissue research 238 (1984), S. 559-564 
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Macrophages ; Ovariectomy ; Rat ; Estradiol administration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Macrophages of the adrenal cortex were studied in normal male and female, ovariectomized and estradiol-injected rats. In normal male rats few macrophages with numerous granules were observed in the zona fasciculatazona reticularis border, and in the zona reticularis. Granules, identified as lysosomes, were limited by a single membrane with a heterogeneous matrix; they exhibited acid phosphatase- and aminotriazole-resistant peroxidatic activities. A larger number of macrophages had identical distributions in normal female rats. In ovariectomized and estradiol-injected rats the number and distribution of adrenal macrophages were similar to those in normal females; however, in spayed animals the number of these cells in the zona reticularis was higher than in the other experimental groups. Lysosomes in macrophages of treated animals were more numerous and their contents more complex than in normal male animals. These results indicate that the adrenal macrophage system is stimulated in experimental conditions involving high levels of circulating estrogens.
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  • 143
    ISSN: 1432-0878
    Keywords: Sympathetic ganglion ; Development, ontogenetic ; Corticosteroid treatment ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Hydrocortisone injections into rats on postnatal days 3–9 caused an increase in the number of small granulecontaining cells in the superior cervical ganglia. These cells, corresponding to the small, intensely fluorescent cells, showed an extensive rough endoplasmic reticulum, a large Golgi apparatus and a very large number of granular vesicles. In addition to the granular vesicles, 70–160 nm in diameter, in which the dense core filled most of the vesicle, most cells of the hydrocortisone-injected rats contained also larger granular vesicles, up to 350 nm in diameter, in which the dense core was eccentrically located. A minority of the cells contained only granular vesicles 70–100 nm in diameter, which was the only type seen in the saline-treated control rats. Thirty days after discontinuation of the hydrocortisone treatment, most of the cells with large granular vesicles had disappeared, and only two profiles of such cells were seen on day 40. The other small cells contained only granular vesicles 70–160 nm in diameter, and these cells could not be distinguished from the small granule-containing cells of 40-day-old control rats treated early postnatally with saline. Hydrocortisone treatment, first on days 3–9 and subsequently on days 40–46, caused reappearance of the small granule-containing cells with large granular vesicles up to 350 nm in diameter, the dense core of which was eccentrically located. Hydrocortisone treatment on days 40–46 only was not followed by appearance of such cells in rats treated with saline on days 3–9.
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  • 144
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    Cell & tissue research 238 (1984), S. 459-474 
    ISSN: 1432-0878
    Keywords: Meningeal compartment ; Perivascular space ; Brain intercellular compartment ; Cerebral cortex ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The intercellular clefts of the brain and the leptomeninges, and the perivascular spaces were studied with reference to the results obtained in a previous study (Krisch et al. 1983). The spatial relationships of these compartments were analyzed at the electron-microscopic level. Horse-radish peroxidase (HRP) was injected into the brain or into the contralateral ventricle. The pattern of distribution of HRP depends on the boundary situation in the individual compartments. The inner and outer pial layers accompany the vessels intruding into the brain. In the Virchow-Robin space the pial funnel obliterates within a short distance. The inner arachnoid layer is continuous with the outer arachnoid layer when it covers the vessels traversing the meningeal space. The perivascular compartment is not in communication with the arachnoid space; moreover, the pial funnel within the Virchow-Robin space is sealed off against the arachnoid space. Thus, blood vessels traversing the meningeal spaces and subsequently penetrating the brain surface are exposed to the common intercellular compartment represented by the intercellular clefts of the brain and the leptomeninges; this compartment does not communicate with the other compartments. The cerebrospinal fluid located in this intercellular compartment is preferentially drained into the upper cervical lymph nodes.
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  • 145
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    Cell & tissue research 238 (1984), S. 635-642 
    ISSN: 1432-0878
    Keywords: Liver ; Endothelium ; Kupffer cells ; Peroxidase ; Cytochemistry ; Ultrastructure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Rat liver fixed by perfusion with low glutaraldehyde concentrations was incubated in diaminobenzidine-containing medium to stain for peroxidase. Endogenous peroxidatic activity was found not only in Kupffer cells but also in the endothelial cells lining the sinusoids and central veins. The reaction product was localized in the nuclear envelope and endoplasmic reticulum. The peroxidatic activity in endothelial cells showed a concentration-dependent sensitivity to glutaraldehyde: in liver samples fixed with 0.25% glutaraldehyde, approx. 23% of the sinusoidal endothelial cells and 65% of central vein endothelium were peroxidase-positive; with 0.5% glutaraldehyde, only approx. 8% of the sinusoidal endothelial cells contained detectable amounts of the reaction product; with 1.5% glutaraldehyde all endothelial cells were consistently peroxidase-negative. No peroxidatic activity could be found in liver endothelial cells following isolation by centrifugal elutriation. Endothelial cell peroxidase may possibly be involved in defense responses of liver and/or, as a part of prostaglandin synthase system, in prostanoid production.
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  • 146
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    European journal of applied physiology 52 (1984), S. 235-242 
    ISSN: 1439-6327
    Keywords: Collagen ; Fast and slow twitch fibres ; Skeletal muscle ; Rat ; Endurance training
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The appearance of collagen around individual fast twitch (FT) and slow twitch (ST) muscle fibres was investigated in skeletal muscles with different contractile properties using endurance trained and untrained rats as experimental animals. The collagenous connective tissue was analyzed by measuring hydroxyproline biochemically and by staining collagenous material histochemically in M. soleus (MS), M. rectus femoris (MRF), and M. gastrocnemius (MG). The concentration of hydroxyproline in the ST fibres dissected from MS (2.72±0.35 Μg·mg−1 d.w.) was significantly higher than that of the FT fibres dissected from MRF (1.52±0.33 Μg·mg−1 d.w.). Similarly, the concentration of hydroxyproline was higher in ST (2.54±0.51 ⧎g·mg−1 d.w.) than in FT fibres (1.60±0.43 Μg·mg−1 d.w.), when the fibres were dissected from the same muscle, MG. Histochemical staining of collagenous material agreed with the biochemical evidence that MS and the slow twitch area of MG are more collagenous than MRF and the fast twitch area of MG both at the level of perimysium and endomysium. The variables were not affected by endurance training. When discussing the role of collagen in the function of skeletal muscle it is suggested that the different functional demands of different skeletal muscles are also reflected in the structure of intramuscular connective tissue, even at the level of endomysial collagen. It is supposed that the known differences in the elastic properties of fast tetanic muscle compared to slow tonic muscle as, e.g., the higher compliance of fast muscle could at least partly be explained in terms of the amount, type, and structure of intramuscular collagen.
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  • 147
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    Journal of chemical ecology 10 (1984), S. 1007-1018 
    ISSN: 1573-1561
    Keywords: Rat ; Rattus norvegicus sp. ; odorants ; stress ; behavior ; open field ; corticosterone ; fox dropping ; ketone ; sulfur ; compounds ; tans ; mercaptoketones ; repellent ; structure-activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The stress for 12 sulfur-containing synthetized volatiles was evaluated in male Wistar rats and compared to that for fox-dropping extract concentrate. Stress behavior was analyzed by quantifying various stress responses in a standard open field and measuring the increase in plasma corticosterone concentration. Nine compounds induced stress—a dihydrothiazole, two cyclic polysulfides, five mercaptoketones, and a mercaptan. For the mercaptoketones, the following structure-activity relationships were observed. Size can vary considerably; the mercapto group can be either alpha or beta and either secondary or tertiary. The keto group is not essential, since a structurally related mercaptan remains active. The mercapto group is essential for activity in mercaptoketones, since conversion to a methyl sulfide resulted in a neutral response. This type of odorant could function as an allomone and may have potential in rat control as an area repellent.
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  • 148
    ISSN: 1435-2451
    Keywords: Hyperthermia ; Induced colonic carcinoma ; Rat ; Chemotherapy ; BCNU ; Ftorafur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Hyperthermie zur Behandlung von Tumoren wird seit längerem in In-vitro- und In-vivo-Versuchen und auch in der Klinik in verschiedenen Anwendungsformen erprobt. Bei der Kombination von Hyperthermie mit Chemotherapie wird eine überadditive cytostatische Wirkung beschrieben. In einem klinisch orientierten, kontrolliert durchgeführten Tierversuch wurde an einem durch N-Nitrosoacetoxymethylmethylamin (AMMN) induzierten autochthonen Coloncarcinom bei Sprague-Dawley-Ratten eine lokale, moderate Hyperthermie (43,5°C, 3 × 60 min) und eine Kombinationsbehandlung von Hyperthermie und Polychemotherapie (BCNU und Ftorafur) durchgeführt unter endoskopischer Diagnosestellung und Verlaufskontrolle. Es konnte keine Überlebenszeitverlängerung durch die angewendeten Therapien und keine additive Wirkung der lokalen moderaten Hyperthermie in Kombination mit der Chemotherapie bei diesem „harten”, d. h. relativ chemotherapieresistenten, Tumormodell gesehen werden.
    Notes: Summary The use of hyperthermia for the treatment of tumors has been tested in in vitro and in vivo experiments as well as clinically for a long time. Combination of hyperthermia with chemotherapy was reported to result in overadditive cytostatic effects. In a clinically adapted, controlled animal experiment, local moderate hyperthermia (43.5°C, 3 × 60 min) alone and in combination with polychemotherapy (BCNU and Ftorafur) was used for the treatment of AMMN-(N-nitrosoacetoxymethyl-methylamine) induced autochthonous colonic carcinomas in Sprague-Dawley rats. Diagnosis and follow-up inspections were carried out endoscopically. The applied therapies did not result in prolonged survival times, nor was an additive effect seen after combined hyperthermia and chemotherapy in this “hard”, i. e. relatively chemotherapy-resistent, tumor model.
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  • 149
    ISSN: 1435-2451
    Keywords: Hyperthermia ; Yoshida sarcoma ; Chemotherapy ; BCNU ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Hyperthermie zur Cytostase von Malignomen ist in zahlreichen In-vitro- und In-vivo-Untersuchungen beschrieben worden. Die Kombination von Chemotherapie mit Hyperthermie soll zur Potenzierung der therapeutischen Wirkung führen. Ein Forschungsgegenstand ist der zeitliche Abstand zwischen beiden Therapiemodalitäten. Anhand eines Yoshida-ColonModells bei Sprague-Dawley-Ratten wurde eine lokale Hyperthermie (43°C, 60 min) im Abstand von 0, 3, 6, 9, 12 und 24 h nach einer Chemotherapie mit BCNU durchgeführt. Die Ergebnisse zeigten keine signifikante Steigerung der Heilungsrate durch die Hyperthermie. Angesichts unserer Ergebnisse sollten z.B. die mit groben Hoffnungen propagierten hyperthermen Peritoneallavagen erst im Tierexperiment einer kontrollierten Untersuchung unterzogen werden.
    Notes: Summary There are numerous reports on in vitro and in vivo investigations of hyperthermia for cytostasis of malignant tumors. Combination of chemotherapy and hyperthermia is to potentiate the therapeutic effect. The time interval between the two types of therapy was the main subject of the present investigation. Local hyperthermia (43°C, 60 min) following BCNU chemotherapy at intervals of 0, 3, 6, 9, 12, and 24 h, respectively, was studied in a colonic Yoshida sarcoma model in Sprague-Dawley rats. No significant increase in the curing rate resulted from hyperthermic treatment. The results suggest that the highly anticipated hyperthermic peritoneal lavages should be investigated in controlled animal experiments prior to clinical use.
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  • 150
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    Gamete Research 10 (1984), S. 107-118 
    ISSN: 0148-7280
    Keywords: Rat ; fertilization ; in vivo ; in vitro ; topography ; egg ; actin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The surface topography of the rat egg was examined during fertilization in vitro and in vivo. Using phase optics, 348 in vitro fertilized and 50 in vivo fertilized eggs were continuously monitored throughout the 7-hour period of sperm incorporation. A myriad of different surface configurations were seen, with each egg exhibiting one or more of the following changes. A small number of eggs (4-6%) formed surface elevations over the sperm head after its detachment from the flagellum, 15-30 min after sperm-egg fusion; 1 to 1.5 hr after fusion, 40-50% of the eggs produced the so-called incorporation cone, a prominent surface elevation over the decondensing sperm nucleus. The vast majority of eggs (74-82%) formed surface elevations over the proximal tip of the flagellum 2-3 hr after sperm-egg fusion. These had no association with the decondensing sperm nucleus. A few eggs (11-12%) exhibited multiple protrusions that were distributed randomly about the egg surface, whereas 14-20% did not manifest any surface elevations and remained spherical throughout the sperm incorporation period. Regardless of the type of surface change, all of the eggs resumed a spherical shape by the time sperm incorporation was complete. These observations are in contrast to the conclusions by previous authors that formation of the so-called incorporation cone over the decondensing sperm nucleus is a ubiquitous event.
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  • 151
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1065-1076 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Various phosphorus-containing polyimides were prepared by the reaction of 1-[(dialkoxyphosphinyl)methyl]-2,4- and -2,6-diaminobenzenes (1) with a tetracarboxylic dianhydride like pyromellitic dianhydride (PMDA) and benzophenone tetracarboxylic dianhydride (BTDA). In addition, copolyimides that contained approximately 3% phosphorus were prepared by the reaction of 1 and m-phenylenediamine (MPD) with the aforementioned tetracarboxylic dianhydrides. Elemental analysis, inherent viscosity, infrared (IR) spectroscopy, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) studies were performed to characterize the polymers. Their thermal properties were compared with those of the corresponding common polyimides. It was shown that the molecular weight and thermal stability of the polymers were reduced as the concentration of the phosphorus moieties increased. The fire-resistance of the copolyimides was evaluated by determining their limiting oxygen index (LOI) value. Copolyimides that contained about 3% phosphorus showed an LOI value approximately 30% higher, than the value of the corresponding common polyimides. In addition, a model diamic acid and diimide was synthesized by the reaction of 1-[di(2-chloroethoxyphosphinyl)methyl]-2,4- and - 2,6-diaminobenzene (DCEPD) with phthalic anhydride and characterized by elemental analysis, IR, proton nuclear magnetic (1H-NMR) spectroscopy, DSC, and TGA. The pyrolysis behavior of the model compounds was investigated by gas chromatography-mass spectrometry (GC-MS). A direct cleavage of the P—C bond and a possible rearrangement to diisocyanates occurred during their pyrolysis.
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  • 152
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1123-1130 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thin film coatings were prepared by polymerizing trifluoromethyl-substituted aromatic compounds in a glow discharge with low power levels and medium pressures. Smooth, continuous films which are adherent and insoluble in conventional solvents were produced. A significant amount of the fluorine content from the monomer was retained in the polymer. The trifluoromethyl group was not removed by the plasma conditions and appeared in the film as trifluoromethyl and difluoromethylene groups. The films were slightly less wettable than those of the unfluorinated films.
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  • 153
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1153-1177 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Asymmetric polyamides from the reaction of either optically active trans-1,2-cyclopropanedicarboxylic acid (C3) or trans-1,2-cyclohexanedicarboxylic acid (C6) with 2,7-diazaspiro[4,4]nonane(DSN) were synthesized. The possible conformations of these polymers and their model compounds in 2,2,2-trifluoroethanol (TFE), water, methanesulfonic acid (MSA), and sulfuric acid were examined by circular dichroism (CD), NMR, viscosity, and dipole moment measurements. The racemic polyamides (±)C3·(±)DSN and (±)C6·(±)DSN exist in extended forms. No intrinsic viscosity changes were observed for these two polymers in TFE and MSA. Certain viscosity and spectral changes have been observed for the optically active polyamides, although no specific ordered conformations can be assigned. The optically active diacid units incorporated into the polymer give a conformation unique from the totally extended chain. CD studies seem to evidence some conformational differences among the polyamide derived from (+)C6 diacid and the optically active DSN. By changing the solvent from TFE to MSA a blue shift of the trough was observed for (+)C6·(±)DSN, a red shift for (+)C6·(-)DSN, and an inversion of the CD spectrum for (+)C6·(+)DSN polyamides. The results of the work with (+)C6·(-)DSN in dilute acid solution suggest that the rotation around the C-N bond is a relatively low-energy process. The spectral and intrinsic viscosity data are consistent with this suggestion. No drastic spectral changes have been observed for the C3·DSN polyamides by changing the solvent from TFE to MSA. The amide group in the C3·DSN polyamide and the corresponding model compound prefer a similar conformation with the carbonyl group bisecting the cyclopropane ring. The C3·DSN polyamide seems to exist in an extended form.
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  • 154
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1515-1524 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The cationic grafting of polystyrene initiated by carbon black containing the CO+ClO-4 group was investigated. The introduction of CO+ClO-4 groups onto a carbon black surface was achieved by the reaction of AgClO4 with carbon black that contained a COCI group. The latter was introduced by the reaction of carboxyl groups with SOCl2. It was found that polystyrene chains could be grown from CO+ClO-4 groups on the surface of carbon black. Moreover, polystyrene was effectively grafted from carbon black: the grafting ratio at 20°C increased to 58% as conversion increased. Furthermore, the grafting ratio and molecular weight of ungrafted polystyrene decreased with an increase in polymerization temperature. These results were explained by the fact that the increasing temperature of the polymerization caused an increase in the rate of chain transfer reaction of the growing polymer chain to the monomer. The carbon black obtained from the reaction produced a stable colloidal dispersion in a good solvent for polystyrene.
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  • 155
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1541-1550 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Radical polymerization of several alkyl allyl oxalates, including methyl allyl oxalate (MAO), ethyl allyl oxalate, propyl allyl oxalate, butyl allyl oxalate, and octyl allyl oxalate, was conducted in the evolution of carbon dioxide at elevated temperatures, and was compared with the anomalous polymerization behavior of diallyl oxalate (DAO) discussed in our earlier articleA. Matsumoto, I. Tamura, M. Yamawaki, and M. Oiwa, J. Polym. Sci. Polym. Chem. Ed., 17, 1419 (1979).. The kinetic equations for the polymerization of alkyl allyl oxalate were derived following the kinetic treatment of the DAO polymerization by further consideration of the absence of cyclization of the growing polymer radical and the effective reinitiation by alkyl radical, and were then satisfactorily applied to the polymerization of MAO, as a representative alkyl allyl oxalate. The evolution of carbon dioxide in the polymerization of alkyl allyl oxalates was enhanced with the increase of bulkiness of the alkyl substituent, as a result of steric suppression of the propagation of the growing polymer radical.
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  • 156
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 17-28 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Plasma polymers synthesized by inductively coupled RF techniques have been investigated as a function of operating parameters for the isomeric perfluorinated diazines (pyrazine, pyrimidine, and pyridazine). A combination of ESCA and microanalytical studies shows that plasma polymers are produced by rearrangement mechanisms: the C/F and C/N stoichiometric ratios are similar to those of the starting monomers over a range of operating parameters. A comparison of rates of formation of plasma polymer films reveals distinctive differences between the isomeric diazines that suggest that equilibration of valence isomers occurs on a substantially slower time scale than for isomeric fluorinated benzenes5-9 which, in general, polymerize at essentially the same rates. In contrast to the remarkably low critical surface tension of plasma polymers based on perfluorobenzenes (ca. 20 dynes cm-2), the plasma polymer films from the perfluorinated diazines which are initially hydrophobic become hydrophilic in contact with water droplets. This is attributed to the hydrolytic instability of films associated with the labilizing influence of nitrogen on nucleophilic displacement of fluoride which is a feature of the chemistry of monomers.
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  • 157
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 49-60 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Studies were conducted on grafting of acrylamide (AM) and sodium-2-acrylamido-2-methylpropane sulfonate (NaAMPS) comonomers onto dextran utilizing Ce(IV) induced initiation. The effects of reaction temperature, the Ce(IV)/dextran ratio, and the AM/NaAMPS ratio on grafting yield were investigated. The graft copolymerization behavior can be explained by exchange of the AMPS anion with one of the ligands on the Ce(IV) initiator. Oxidative modification of the dextran substrate improved the yield of graft copolymer. The dextran-g-poly(acrylamido-co-sodium-2-acrylamido-2-methylpropane sulfonate) samples prepared by this method were characterized as to copolymer composition and molecular weight utilizing elemental analysis, dilute solution viscometry, and aqueous size exclusion chromatography. Relationships of molecular weight and charge density to kinematic viscosity and salt sensitivity are discussed.
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  • 158
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 77-84 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photoinitiated cationic polymerization by photosensitization of diphenyliodonium and triphenylsulfonium salts is shown to proceed by two distinct electron transfer process: (1) direct electron transfer from excited-state photosensitizers and (2) indirect electron transfer from photogenerated radicals. The efficiency of the former process is attributed to the instability of the reduction products (from diphenyliodonium and triphenylsulfonium salts), which dissociate in competition with undergoing energy-wastage reverse electron transfer. Amplification of photons in the production of protons (or other reactive cations) is postulated to account for the high quantum yields observed in the latter process. Potential advantages of utilizing the indirect redox process in the design of UV curable hybrid systems, which contain functionality for both radical and cationic polymerization, are noted. The results also provide evidence against the importance of triplet states of the onium salts in photoinitiator activity.
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  • 159
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 107-120 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Racemic and optically active N-carboxyanhydrides (NCA)s of 2-methyl- and cis-6-methylpipecolic acid, when subjected to polymerization conditions in solution or in bulk whether with “weak” or “strong” base initiators, resisted polymerization under all conditions tried. Instead, the NCA of 2-methylpipecolic acid gave the corresponding cyclic dipeptide and the NCA of cis-6-methylpipecolic acid formed the cyclic dipeptide derived from trans-6-methylpipecolic acid. The mechanism of dimerization of these NCA's was investigated. Evidence was provided for the proposed mechanism in which the active moiety is not a carbamate ion but an amino group. Methyl 2-methylpipecolate underwent an intermolecular SN2-type reaction upon heating, yielding equimolar quantities of methyl N-methyl-2-methylpipecolate and 2-methylpipecolic acid.
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  • 160
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 135-144 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of a range of 10 organic nitriles on the radiation-induced polymerization of styrene was studied. A dose rate of 4.4 rad s-1 was used. A rate of polymerization of styrene (1.744 mol L-1 of toluene solution) of 5.0 × 10-7 mol L-1 s-1 was found. With organic nitriles present (styrene:nitrile ratio of 1:0.28) the rate of polymerization increased. Rates in the range of 5.5 × 10-7 -5.2 × 10-6 mol L-1 s-1, depending on the nitrile present, were obtained. The polymers were partially characterized and evidence of involvement of each of the nitriles in the polymer chains was revealed. The increase in rate of polymerization has been attributed to the part played by nitrile radicals in the initiation of styrene polymerization. Radical yield values [as G(nitrile radical)] were derived from the relevant rate expressions. Values ranged from 2.7 to 49.5, depending on the particular nitrile. Corresponding values of G(nitrile radical) in the range of 5.1-129.4 were obtained by the manipulation of number-average molar mass data. Values of kpkt of approximately 2 × 10-5 L mol-1 s-1 were found. Trommsdorff types of effect are absent from these systems.
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  • 161
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 213-223 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of parasubstituents on the radiation chemistry of poly(α-methylstyrene) (PMS) was compared for the fluoro (PFMS), chloro (PCMS), bromo (PBMS), isopropyl (PiPMS), and methoxy (PMeOM) derivatives. Radiolysis yields, ESR spectra, and GC—MS analysis of products were obtained. PMS and PFMS have similar low radiolysis yields, products, and product distributions. Only main-chain radicals which persist to 200° were observed. PCMS has increased values of Gs, Gx, and Gr. The product analysis results suggest that the presence of chlorine contributes to the primary process by dissociative electron capture and enhances the cleavage of α-methyl group. Irradiation of PBMS caused crosslinking and yielded few volatile products. PMeOMS and PiPMS gel readily by γ-irradiation and may be useful as negative radiation resists.
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  • 162
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 225-238 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High molecular weight polysilane copolymers which contain the units in the title were prepared in high yield by sodium coupling the corresponding organodichlorosilanes in toluene. These copolymers are highly soluble in common solvents and can be drawn into fibers or formed into films by molding or casting. They are also photoactive.
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  • 163
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 277-281 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 164
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 303-318 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Iron-ion-containing polymers were prepared by reacting atactic polyvinylpyridine with ferric chloride or ferric nitrate in methanol solution. Molar ratios of Fe3+ to 4-vinylpyridine (Fe:PVP) were 1:2, 1:6, and 1:20. Three kinds of iron center were characterized from 57Fe Mössbauer spectra recorded over a temperature range of 4.2-290 K. Infrared (IR) spectra of the samples were measured also. All samples contained amorphous hydrated ferric-oxide particles that exhibited superparamagnetic behavior at low temperatures. The size of the clusters (102-103 iron atoms per particle) was estimated from the average blocking temperatures TBav, which is sensitive to the Fe:PVP ratio. For FeCl3:PVP preparations with Fe:PVP of 1:2, 1:6, and 1:20 TBav was 37, 10, and 〈4 K, respectively. A small proportion (〈10%) of high-spin ferrous iron centers was found in most samples. A third type of signal attributable to oxygen-bridged ferric dimers was found in FeCl3-PVP preparations with Fe:PVP of 1:2 or 1:6 but not in Fe(No3)3-PVP samples. This species is probably [Cl3Fe—O—FeCl3]2-. Interactions between the polymer and the various iron centers were weak.
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  • 165
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 341-352 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Five general routes for the preparation of polyoxyethylene [generally referred to as poly(ethylene glycol) or PEG] derivatives are described. These routes are (1) nucleophilic displacements with the alkoxide of PEG, (2) nucleophilic displacement on PEG-tosylate, -mesylate, or -bromide, (3) reductive amination of PEG-aldehyde, (4) reductive amination of PEG-amine, and (5) nucleophilic displacements on the s-triazine derivatives prepared from s-triazine trichloride (cyanuric chloride) and PEG. Eighteen derivatives are prepared and potential applications to catalysis, cell purifications, and other areas are discussed briefly.
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  • 166
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 391-406 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polymerization of 6-amino-2,4-trans,trans-hexadienoic acid and various of its salts was studied in the solid state. Crystals of the hydrochloride and organic inorganic double halides with cadmium chloride, manganese (II) chloride, and iron(II) chloride were found to polymerize rapidly upon UV or γ irradiation. An erythro-diisotactic polymer is obtained in the form of extended chain crystals. The polymer behaves as an amphoteric polyelectrolyte. The kinetics and the mechanism of the polymerization as well as morphological changes during the solid state reaction are discussed.
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  • 167
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 419-428 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ESCA and contact-angle (H2O and CH2I2) measurements are used to follow changes in the surface of poly(ethylene terephthalate) film photooxidized (254 nm radiation in O2) for varying times, followed by aging for as many as three weeks or washing with water. Photooxidation occurs uniformly throughout the outermost 50 Å of the film to give a surface stoichiometry that corresponds to C10O6.6. Oxidation produces mainly carboxyl (acid) and alcohol/phenol groups, carbonyls form after extensive treatment. Low molecular weight products formed by chain scission and oxidation are removed by washing and diffuse into the bulk when aged. Oxidized products in higher molecular weight chains are not removed by washing, but can diffuse into the polymer bulk or reorient because of their chain mobility; therefore they are directed toward the polymer bulk rather than the surface. Extended photooxidation produces a stable oxidized surface more resistant to aging changes. The results are compared with those obtained for poly(ethylene terephthalate) film oxidized in an electrical discharge.
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  • 168
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 463-473 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The absolute rate constants of propagation (kp) and of termination (kt) of N-acryloylpiperidine (NAPi) were determined by the rotating sector method in bulk; kp = 273 and kt = 1.79 × 107 L/mol s at 30°C. It was noted that kp for NAPi was 100 times smaller than that for N,N-dimethylacrylamide (DMAcAm). The absolute rate constants of cross-propagations for copolymerizations with common monomers were evaluated by combination of the kp value and the monomer reactivity ratios. Quantitative comparison of the rate constants with those of DMAcAm and poly(DMAcAm) radical shows that NAPi is as reactive as DMAcAm and the smaller kp value for NAPi is ascribable to much the lower reactivity of the poly(NAPi) radical. The large difference in reactivity of the polymer radicals is discussed in relation to the steric factor of the piperadino and the dimethylamino groups which seems to affect the capability of the carboxamide group to stabilize the polymer radical.
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  • 169
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 493-502 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preirradiation grafting of N-vinylpyrrolidone (NVP) onto poly(tetrafluoroethylene) (PTFE) and poly(tetrafluoroethylene-hexafluoropropylene) (FEP) films was investigated. The influence of grafting parameters such as preirradiation dose, monomer concentration, and grafting temperature on the rate and grafting yield was studied. Different solvents were used for diluting the monomer and it was found that the aqueous monomer solution at a concentration of 80 wt% was suitable for this grafting system. However, the graft polymerization of NVP in benzene terminated within a short time without significant grafting yield. The dependence of the grafting rate on preirradiation dose and monomer concentration was 1.2 and 1.07 order, respectively, for grafting onto PTFE films and 1.1 and 1.2 order, respectively, for grafting onto FEP films. Arrhenius plots for grafting onto PTFE films showed a breaking point at ca. 35°C and the overall activation energies were calculated as 23.6 and 9.0 Kcal/mol below and above 35°C, respectively. For grafting onto FEP films, however, no break was observed in the Arrhenius plots; the overall activation energy was 11.9 Kcal/mol. The swelling behavior and electric resistance of the grafted materials were investigated.
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  • 170
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    Keywords: Physics ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology
    Notes: Several polythioesters by interfacial polycondensation of 1,4-di(mercaptomethyl)-2,3,5,6-tetramethylbenzene with oxalyl, succinyl, adipoyl, suberoyl, and sebacoyl chlorides were obtained. To determine the optimal conditions for interfacial polycondensation, the influence of the following factors on yield and value of reduced viscosity were studied: type of organic phase, concentration of hydrogen chloride acceptor, the quantitative ratio of aqueous to organic phase, molar ratio of reagents; temperature of reaction, rate of acid chloride addition, and contribution of catalyst. Thorough studies were carried out only for polycondensation of the dithiol with adipoyl and sebacoyl chlorides. The structure of all polythioesters obtained under the model conditions was determined by elementary analysis and infrared spectra. Initial decomposition temperature, mass loss in percentage at the same temperature, maximum rate of decomposition, and mass loss percentage at 100-400°C were defined by thermogravimetric analyses. Chemical resistance of the polythioesters was determined by treatment with some organic solvents, mineral acids (concentrated and 10%), and sodium hydroxide (10 and 50%). Some mechanical and electrical properties of the polythioesters obtained from dithiol and adipoyl and sebacoyl chlorides were determined. The molecular weight was not measured because of the low solubility of the polythioesters.
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  • 171
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    Keywords: Physics ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology
    Notes: The anionic polymerization of norbornene trisulfide initiated with sodium thiophenoxide (sodium cation solvated with dibenzo-18-crown-6 ether) was studied. Polymers with high molecular weights were obtained (Mn up to 105, osmometrically). Molecular weights calculated for living polymerization conditions (i.e., one molecule of initiator yields one macromolecule) agree well with Mn measured by osmometry. 1H-NMR, 13C-{1H}-NMR, and Raman spectra of the polymer are given. Thermodynamics of polymerization in toluene solvent is described. Enthalpy ΔHss = -(1.39 ± 0.17) kcal mol-1 and entropy ΔSss = -(7.52 ± 0.55) cal mol-1 deg-1 coefficients of polymerization were evaluated from the temperature dependence of the equilibrium monomer concentration determined dilatometrically.
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  • 172
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1141-1151 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A fire- and heat-resistant polymer was obtained by the thermal polymerization of bismaleimido-substituted 2,2-bis(anilino)-4,4,6,6-tetrakis-(4-Aminophenoxy)-cyclotriphosphazene. The thermal stabilities of the polymer were evaluated in nitrogen and in air by thermogravimetric analysis. This polymer was stable to 345°C and had char yields of 78% at 800°C in nitrogen and of 71% at 700°C in air. The structures of cyclotriphosphazene precursors and the polymer were characterized using Fourier-transform infrared and proton nuclear magnetic resonance spectroscopy.
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  • 173
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1187-1190 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
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  • 174
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1197-1200 
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    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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  • 175
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1243-1250 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rate of reaction of alkyl halides with aqueous sodium acetate or cyanide catalyzed by phosphonium salts supported on insoluble polystyrene resins, and rates of ion-exchange of the chloride ion in the catalysts against the acetate ion, were studied as a function of catalyst particle size, the percentage of ring substitution, the morphology of polymer support, and distance between active site and polymer backbone. Rates of 1-bromooctane or benzyl chloride with macroporous, 7-25% ring-substituted catalysts increased with increasing ring substitution. Rates with macroporous catalysts increased as a heptamethylene spacer was introduced between the active site and the polymer backbone. Rates of ion-exchange with macroporous catalysts were facilitated with increasing ring substitution or by the introduction of the spacer chain. A relation between the catalytic activity of macroporous or microporous catalysts and ion-exchange rates under triphase conditions was discussed.
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  • 176
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1251-1258 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polymerization of the cyclic amide of PIII is described for the first time. The N,N-diethylamine-1,3,2-dioxaphosphorinan was shown to give living reversible polymerization with anionic initiators. Lithium and sodium derivatives were found to be inactive. 1H-, 13C-, and 31P-NMR indicated that the polymer strictly reflects the monomer structure and is formed without any isomerization, the polymer chain being $\rlap{--} ({\rm OP}\left( {{\rm NR}_{\rm 2} } \right){\rm O(CH}_{\rm 2} \rlap{--} )_3 )_n $. Initiation involves attack of the anion on the P atom. From the dependence of the equilibrium monomer concentration on temeprature ΔH1s = 1.5 ± 0.2 kcal·mol-1 and ΔS1s = 4.6 ± 0.6 cal·mol-1·°K-1.
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  • 177
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    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The interaction of α-poly-L-lysine and ε-poly-L-lysine with methyl and ethyl orange was studied by equilibrium dialysis and spectroscopic methods. The results of the dialysis measurements indicated that the extent of binding by ε-polypeptide is substantially higher than that by α-polypeptide, despite the much greater molecular weight of the latter. This difference in binding affinity was interpreted in terms of the increased conformational adaptability of ε-polypeptide because of its highly flexible structure. Furthermore, ε-polypeptide exhibited strong cooperative binding. In addition, the effect of the successive addition of α- and ε-polypeptides on the absorption spectra of methyl and ethyl orange was investigated. The addition of α-polypeptide with a molecular weight of 400,000 produced a new absorption peak at a shorter wavelength, due to the stacked dye molecules on the polypeptide chain, whereas that of ε-polypeptide did not. From the results of spectroscopic measurements a possible mode of interaction between these two polypeptides and the small molecule is discussed.
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  • 178
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1327-1333 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Grafted PMMA was isolated by the acid hydrolysis method. Weight-average and number-average molecular weights were determined by gel permeation chromatography. The number-average molecular weight of the grafted chains was about 475,000 for amylopectin and 403,000 for amylose. The number of grafted chains (mmol) ranged from 2.4 × 10-3 to 4.6 × 10-3 for amylopectin graft copolymers and from 2.9 × 10-3 to 6.8 × 10-3 for those of amylose. These results were related to others obtained from ceric ion consumption studies. The values suggest that amylopectin, because of its complex structure, favors a higher consumption of ceric ion in homopolymerization reactions and inhibits the initiation reactions of the copolymerization.
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  • 179
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1365-1372 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The progressive dissolution of carboxylated latex particles with increasing pH was utilized to investigate the internal structure of core-shell latex particles, in comparison with that of copolymeric latex particles formed from the same monomers. The results indicated that in those latex particles which are formed when ethyl acrylate (EA) -methacrylic acid (MAA) or methyl acrylate (MA) -MAA mixture is polymerized in the presence of poly(MA-MAA) or poly(EA-MAA) seeds the shell is composed of the more hydrophilic poly(MA-MAA) molecules relatively high in MAA content and the core is composed of both poly(MA-MAA) and poly(EA-MAA) molecules, regardless of the order of the stage feed, while the copolymeric latex particles are relatively uniform from surface to center in distribution of all components except MAA. Examination of the distribution of the carboxylic groups in all of the latex particles showed their concentration to be highest at the surface and to decrease with proximity to the center in accordance with other findings reported in the literature.
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  • 180
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1409-1417 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The emulsion polymerization of styrene initiated by potassium persulfate catalyzed by Ti+3 ions was studied. Two sources of Ti+3 ions were used: the titanium trichloride and titanium sulfate. It was found that the titanium ions used in conjunction with potassium persulfate decrease both the reaction rate and the average molecular weight. An even greater drop of reaction rate was noted when chlorine anions (TiCl3) were present. The presence of these ions had a stabilizing effect on the polydispersity.
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  • 181
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1471-1479 
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    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mass spectroscopy was done at different temperatures on epoxylated novolac resin DEN 438 (Dow Chemical Co.) alone, and after curing with various metal(II) phthalocyanine tetraamines (MPTA). Possible modes of fragmentation are given to explain the experimental results. Gas-chromatographic/mass-spectroscopic (GC-MS) analyses of MPTA derivatives indicated the presence of only trace quantities of benzene, aniline, cyanobenzene, and orthodicyanobenzene. The GC-MS studies of the cured DEN 438 epoxy resins indicated that the mechanisms of thermal degradation are qualitatively similar, and some common features were observed in their fragmentation in an electron beam and by thermal degradation. This study is a further assessment of the utility of these phthalocyanine derivatives for curing epoxy resins to produce heat-resistant polymer systems.
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  • 182
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1507-1514 
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    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The initiation mechanism on the radical polymerization of vinyl monomers by polyethyleneglycol (PEG-300) in aqueous solution was studied. The initiating radical species were determined by means of the spin trapping technique. They were concluded to be generated by the hydrogen atom transfer from the monomer adsorbed at the ether group of PEG-300 to the free monomer.
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  • 183
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1535-1540 
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    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The stereospecificity of benzyl derivatives of trivalent titanium (Rn TiX3-n, where X = Cl, I, n = 1-3) in butadiene polymerization was studied. It was found that dibenzyltitaniumiodide is an efficient catalyst of the 1,4-cis-polymerization of butadiene and that tribenzyltitanium forms 1,2-units. In both cases all the titanium-benzyl bonds participated in the initiation reaction and the active sites were polymeric analogues of crotyl derivatives of Ti(III); namely, bis-π-oligobutadienyltitaniumiodide and tris-π-oligobutadienyltitanium. These sites are stable at room temperature. The nature of the active sites in the polymerization of butadiene with Ziegler's 1,4-stereo-specific systems Til4 (or Til2Cl2) + AIR3 are described.
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  • 184
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1573-1578 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: When 4-hydroxy-2,2,6,6-tetramethyl piperidinoxyl (HTMPO) is processed in polypropylene in a closed mixer, almost 50% is converted to other products during the first few minutes whilst the applied torque in the mixer is high. There is associated formation of unsaturation and this fact, in conjunction with the almost complete regeneration of nitroxyl within five minutes, suggests that the corresponding hydroxylamine (HTMPOH), which can be qualitatively identified, is the major transformation product. A study of the UV stability of PP films fabricated from polymer processed for varying times shows that UV stability is related to the quantity of the redox couple (HTMPO + HTMPOH) remaining in the polymer. This is considerably reduced by severe processing. The redox capable has almost no thermal antioxidant (oven aging) activity.
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  • 185
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1611-1621 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polyamides 6.10 and 6.6 (PA* 6.10 and 6.6) containing small amounts of —N=N— units in the main chains were prepared by interfacial polycondensation between hexamethylenediamine and sebacoyl chloride or adipoyl chloride with addition of azobiscyanopentanoyl chloride. Polyamide-polystyrene block copolymers (PA-b-PSt) were then prepared by decomposition of the —N=N— units of PA*, initiating radical polymerization of styrene in m-cresol. The average PA block length of PA-b-PSt thus formed was longer than that expected from the initially present PA segments between the —N=N— units. This is probably due to recombination of PA radicals whose initiation efficiency is as low as 15%. The PSt blocks also had higher molecular weight (7000-79,000) in comparison with homopolystyrene produced from monomeric azobiscyanopentanoic acid used as an initiator due to higher viscosity of polymerization system. Variation of intrinsic viscosity and turbidimetric titration behavior along with the change in composition were also discussed.
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  • 186
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1603-1610 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polymerization of trimethylsilylacetylene was investigated by using W and Mo catalysts. Mixtures of WCl6 with appropriate organometallic cocatalysts such as n-Bu4Sn and Et3SiH at 1:1 molar ratio provided poly(trimethylsilylacetylene) in high yields. On the other hand, MoCI5 gave mainly methanol-soluble oligomers even in the presence of these cocatalysts. The polymer formed was a partly insoluble yellow powder, and the molecular weight of the soluble fraction was about 7000. The IR, 1H-NMR, and 13C-NMR spectra supported the polymer structure, (CH = CSiMe3)n. Protodesilylation of poly(trimethylsilylacetylene) afforded a new polymer containing both acetylene and trimethylsilylacetylene units.
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  • 187
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1733-1742 
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    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cationic oligomerization of bicyclic oxalactam, 8-oxa-6-azabicyclo[3.2.1]octan-7-one [abbreviated as BOL (1)], was carried out at 0-60°C with trifluoromethanesulfonic acid and borontrifluoride etherate as catalysts to obtain the oligomer mixture at high yield. From the structural analysis of the isolated dimer, a N-(2(e)-carbamoyltetrahydropyran-6(e)-yl)-8-oxa-6-azabicyclo[3.2.1]octan-7-one, the oligomerization proceeded through the 5C-6N scission in (1) but not through the 6N-7C (amide group) scission as generally observed in common lactams. This peculiar oligomerization must result from the protonation to the oxamide unit in the BOL molecule.
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  • 188
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1775-1782 
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    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 8 Ill.
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  • 189
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1803-1815 
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    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of aqueous polymerization of acrylamide with KMnO4/glycine redox pair was studied in an atmosphere of nitrogen at 35 ± 0.2°C. The rate of polymerization was found to be first power on monomer, activator, and catalyst concentration. The overall energy of activation was calculated to be 15.66 kcal/deg mol (65.54 kJ/mol) between 30 and 50°C. The effects of various additives (alcohols, neutral salts, complexing agents, addition of catalyst) were studied. The dependence of the polymerization rate on the activator and catalyst concentration was studied in DMF-water mixture also. The molecular weight of polymer was determined at various temperatures of the reaction medium.
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  • 190
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1743-1756 
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    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several polyamides of p-phenylenedioxydiacetic acid (PDDA) were synthesized by the low-temperature solution polycondensation techniques. Six different diamines were condensed independently with p-phenylenedioxydiacetyl chloride (PDC) in a mixture of N-methyl pyrolidone (NMP) and hexamethyl phosphoramide (HMPA). The polymers were obtained in 80-95% yield and possessed inherent viscosities in the range 0.32-0.81 dL/g. The polymers were characterized by infrared (IR) and H1-NMR spectra. The solubility, density, crystallinity, and thermal stability of the polyamides were also determined. A model diamide (MDA-1) was also synthesized from aniline and PDC to confirm the formation of polyamides from diamines.
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  • 191
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1797-1801 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The radiation degradation of viscoelastic solutions of a dialkyl monohydroxy aluminum polymer compound (AIR2OH)x is investigated. Radioactive cobalt-60 is chosen for irradiation experiments. The viscosity of the polymer in six different solvents is measured after irradiation using a capillary viscometer at room temperature (25°C). The degradation effects on both the radiation dose and the solvent used.
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  • 192
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    Topics: Chemistry and Pharmacology
    Notes: Asymmetric selective (or stereoelective) polymerization of racemic 1,2-diphenylethyl methacrylate (DPEMA) with ethylmagnesium bromide (EtMgBr)-(-)-sparteine catalyst was studied in toluene at -78°C. In the polymerization (S) enantiomer was consumed preferentially and the enantiomeric excess of initially polymerized (S) enantiomer was consumed preferentially and the enantiomeric excess of initially polymerized DPEMA was greater than 90%. Optically pure (R) monomer was recovered at about 70% polymer yield. Poly(DPEMA) obtained with EtMgBr-(-)-sparteine complex was highly isotactic. It was found in the polymerization of optically active DPEMA that optical rotation of poly(DPEMA) was dependent on the tacticity and that isotactic and syndiotactic poly(DPEMA)s showed opposite optical rotations. Circular dichroism spectra of the optically active polymers were measured.
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  • 193
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1865-1873 
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    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The laser-initiated polymerization of a thiol-ene photopolymerizable system was studied. The laser was operated in single- and multiple-pulse modes to generate exotherms, which were measured in a modified differential scanning calorimeter. Arrhenius plots of the polymerization, obtained by measuring polymerization exotherms at various temperatures, showed positive and negative portions. Pseudoactivation energies for the thiol-ene polymerization increased rapidly at low conversions (〈50%) of the thiol and ene chromophores. The results were comparable to those obtained from photopolymerization of multifunctional acrylate monomers.
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  • 194
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1909-1921 
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    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: By exposure to ultraviolet and gamma radiation and by the usual methods of thermal polymerization, the stereospecific polymerization of methyl aryloxymethacrylates was carried out at different temperatures in several solvents. Triad tacticity values of the polymers obtained by free-radical and ionic routes were computed from nuclear magnetic resonance spectral data. Results of this investigation support our earlier observationSee: K. Saunders, T. Balakrishnan, R. W. Lenz, and K. Hatada, Macromolecules, 12, 392 (1979). that, under the conditions used, heterotactic content is the maximum in most of these polymers, thereby justifying the high steric effect of the bulky and polar aryloxy side chain which offers equal isotactic and syndiotactic placements.
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  • 195
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1987-1996 
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    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The cationic, ring-opening polymerization of 1,6-anhydro-3,4-di-O-benzyl-2-deoxy-β-D-arabino-hexopyranose (ABDA) (=1,6-anhydro-3,4-di-O-benzyl-2-deoxy-β-D-glucopyranose) was investigated with Lewis acid as catalyst. Phosphorus pentafluoride at -78°C caused polymerization to a highly stereoregular (1 → 6)-α-linked polysaccharide. Effects of C-2 substituent on the polymerization of 1,6-anhydro sugar are discussed. In addition, copolymerization of ABDA (M1) with 1,6-anhydro-2,3,4-tri-O-benzyl-β-D-glucopyranose (LGTBE, M2) was studied. The monomer reactivity ratios calculated by the Kelen-Tüdös method were r1 = 4.46 and r2 = 1.66. Debenzylation of the polymer produced 2-deoxy-(1 → 6)-α-D-arabino-hexopyranan in which every repeating unit contained two free hydroxyl groups.
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  • 196
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 2381-2393 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The absolute rate constants for propagation (kp) and for termination (kt) of ethyl α-fluoroacrylate (EFA) were determined by means of the rotating sector method; kp = 1120 and kt = 4.8 × 108 L/mol.s at 30°C. The monomer reactivity ratios for the copolymerizations with various monomers were obtained. By combining the kp values for EFA from the present study and those for common monomers with the monomer reactivity ratios, the absolute values of the rate constants for cross-propagations were also evaluated. Reactivities of EFA and poly(EFA) radical, being compared with those of methyl acrylate and its polymer radical, were found to be little affected by the α-fluoro substitution. Poly(EFA) prepared with the radical initiator was characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Although the glass transition temperature obtained by DSC for poly(EFA) resembled that of poly(ethyl α-chloroacrylate), its TGA thermogram showed fast chain de polymerization to EFA that was distinct from complicated degradation of poly(ethyl α-chloroacrylate).
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 197
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A polymethacrylate derivative containing uracil bases was methylated by using methyl iodide or dimethyl sulfate to give polymers containing 3-methyluracil derivatives. In the case of methylation with dimethyl sulfate, sulfonation at 5-position of the bases occurred in addition to the methylation at N-3 position. The methylated polymers thus obtained were used further for the study of polymer complex formation with polymethacrylate containing adenine base.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 198
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 2523-2531 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polyelectrolyte submicron microcapsules were prepared by interfacial crosslinking of an aqueous salt solution of poly(ethyleneimine) and a toluene solution of brominated poly-(2,6-dimethylphenylene oxide). The two solutions were brought together and mixed by sonication. As a result, a stable emulsion was obtained, which was subsequently cast into a membrane in which the microcapsules were embedded. The salt solution contained in the microcapsules could be released under controlled conditions. The rates of release were measured. They could be controlled by applying osmotic pressures, by additional quaternization of the membrane, or by modification of the structure of the capsule wall by introduction of a surfactant.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 199
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 2539-2550 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A combined (chemical and infrared (IR) spectrophotometric) method is discussed for the simultaneous determination of concentrations of carboxyl (A), ketone (K), and ester (E) groups formed in the oxidation of polyethylene (PE). The IR absorptivities of these functional groups were determined by using model compounds [stearic acid, stearone, poly-(1,4-butylene sebacate)]. The integral absorption of the C=O band of polymer samples which contained several oxo groups of different types was found to be additive. This method was applied to the determination of the carboxyl, ester, and ketone content of samples oxidized at different oxygen pressures.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 200
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 2579-2599 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polyamides and related model compounds were prepared from carboxy acids and primary amines by reacting them with triphenylphosphite in an appropriate solvent at 100°C. The reactions proceeded in the absence of organic base but were accelerated by the addition of bases such as pyridine. Nevertheless, even the powerful combination of 13C and 31P NMR failed to indicate the presence of pyridinium phosphite in the reaction mixture. In the reaction of a primary amine and carboxyl groups a detectable amount of the diphenoxy aminophosphine intermediate was observed. The end products are the amides, phenol, and diphenyl phosphite. When primary amine was not present a slow formation of a phenyl ester of the carboxylic acid was evident. All the intermediate species and the end products were formed with or without added pyridine. A mixed anhydride of carboxylic acid and phosphite was never seen. The results in this article are fundamentally the same as those in the companion article (I) for which the data were obtained at 280°C in the absence of solvent and base. However, because the reaction went quickly to completion at 280°C, the diphenoxy aminophosphine intermediate was not observed. A mechanism for the amidation in which the diphenoxy aminophosphine is an initial reaction intermediate is proposed. This species reacts with the carboxylic acid through an intramolecular substitution to give an amide. This mechanism may be valid for the high-temperature reactions as well. Several minor unclear points are indicated.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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