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  • 1980-1984  (50)
  • 1925-1929  (22)
  • 1830-1839  (10)
  • Organic Chemistry  (46)
  • General Chemistry  (33)
  • DNA  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 276 (1984), S. 52-56 
    ISSN: 1432-069X
    Keywords: Fluorometry ; DNA ; 4′-6-Diamidino-2-phenylindole ; Fibroblasts ; Epidermis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 4′-6-diamidino-phenylindole (DAPI) which is used for the detection of mycoplasmic infections of cell cultures or cytofluorometric investigations proved to be a sensitive agent for the fluorometric assay of alkali extracted DNA in cultured cells and human epidermis. Various experiments to optimize assay conditions led to the following procedure: 1 part of freeze dried tissue (1 mg/ml) and 1 part of 0.2 mol/l NaOH (w/v) were heated at 95° for 40 min. After cooling for 1 h to room temperature, 0.1 ml alkaline extract was mixed with 2.9 ml DAPI-solution (0.2 μg/ml in McIlvaine buffer containing 1 mmol/l MgCl2). After 10 min in the dark the emitted fluorescence was estimated at 453 nm with an excitation at 360 nm. This assay procedure allowed a detection limit of 25 ng DNA.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Planta 152 (1981), S. 1-7 
    ISSN: 1432-2048
    Keywords: Auxin ; Cytokinin ; DNA ; Nicotiana RNA ; Protoplasts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Tobacco mesophyll protoplasts cultivated in vitro do not synthesize a measurable quantity of chloroplastic ribosomal RNA, but actively synthesize cytoplasmic ribosomal RNA, polyadenylated RNA, and proteins. These syntheses are essentially independent of the presence of hormones in the culture medium and are thus related to the ageing phenomenon induced by isolation from the plant and in-vitro culture. At all stages of culture and in all culture media, protoplasts incorporate low levels of thymidine into their DNA. However, the incorporation of considerable quantities of thymidine, indicative of the S phase, only takes place after 25–30 h and requires the presence of auxin and cytokinin.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 4 (1984), S. 79-88 
    ISSN: 1573-7217
    Keywords: breast ; carcinoma ; DNA ; kinetics ; ploidy ; receptors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The S-phase fraction (SPF) measured by flow cytometry of DNA and the thymidine labeling index (TLI) measured autoradiographically indicate the proportion of carcinoma cells currently synthesizing DNA and reflect the rate of proliferation. The TLI and SPF are lognormally distributed. The median TLI performed to maximize precursor uptake is near 5% (5 labeled carcinoma cells per 100), the mean near 7%, and the range from less than 1% to near 40%. Corresponding values for the SPF measured by DNA flow cytometry are slightly higher when appropriate measures are taken to reduce background debris counts and other artefacts. Residual elevation of SPF above TLI may result from S-phase arrested cells. Flow cytometric histograms show that clearly aneuploid cell lines exist in 50–80% of primary breast carcinomas. Aneuploid breast carcinomas have higher mean TLI than diploid breast carcinomas, and therefore proliferate more rapidly. They also more frequently lack estrogen receptor (ER). Carcinomas with minimal nuclear anaplasia, particularly those of tubular, mucinous, infiltrating lobular and adenocystic types have low TLI and SPF, whereas carcinomas with highly anaplastic nuclei, including medullary carcinomas, have high TLI and SPF. TLI and SPF correlate inversely with ER and PgR content, have no relationship to axillary lymph nodal status, and have a weak positive correlation with tumor size and a weak negative correlation with age. High TLI predicts a high risk of early relapse after primary therapy for both node-negative and node-positive carcinomas. Carcinomas that produce brain metastases have particularly high TLI. Current evidence suggests that high SPF and aneuploidy may prove to have prognostic significance like TLI.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 1058-1062 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rates of proton transfer from 2, 4-hexadiene, 1, 3-cycloheptadiene, cyclopentadiene and acetone to t-butoxide have been measured in the gas phase using pulsed-ion-cyclotron-resonance spectroscopy. The rate constants are (units of 10-10 cm3 molecule-1 s-1): 2.7 ± 0.4, 3.8 ± 0.4, 6.1 ± 0.7 and 10.8 ± 1.5, respectively. These results are analyzed in terms of the properties of the encounter complex and reaction transition states. The reaction profile for t-butoxide + cyclopentadiene is modeled using RRKM theory and an estimate for the central barrier height is obtained.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Irradiation of (RS,SR)-3-Phenyl-6-hepten-2-ol (3n) gave the photoproducts 6n-10n. Some reactions of 6n and 8n are reported. The regio- and diastereoselectivity observed in the photoreaction of substituted 5-phenylpentenes is discussed with respect to conformational preferences of the compounds to be irradiated.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preparation of Styryl and Distyryl Derivatives of Pyridine2,4-, 2,5- and 2,6-Dimethylpyridines react with anils of aromatic aldehydes in the presence of dimethylformamide and potassium hydroxide to yield the corresponding distyrylpyridines (‘anil synthesis’). Under the same reaction conditions (4-methylstyryl)pyridines are converted to (stilbenylvinyl)pyridines. Similarly, the Schiff's base derived from pyridine-3-carbaldehyde and p-chloroaniline on treatment with methyl- and p-tolyl-substituted aromatic heterocycles gives the corresponding (heteroaryl-styryl)pyridines, whereas with the Schiff's bases derived from pyridine-2- and -4-carbaldehyde side reactions, such as dimerization followed by disproportionation predominate.
    Additional Material: 24 Tab.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 66 (1983), S. 898-901 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Studies of Organometallic Compounds. Synthesis and Characterization of Some Alkoxy (alkyl)-titanium(IV) CompoundsAlkoxy(benzyl)titanium and alkoxy(cyclohexyl)titanium compounds are prepared by alcoholysis of tetrabenzyl- and tetracyclohexyltitanium. Structural features are investigated by means of 1H-NMR.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 8 (1925), S. 74-83 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 8 (1925), S. 637-650 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 65 (1982), S. 934-943 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Annular compounds containing two PAuP-entities are prepared by reaction of (trialkylphosphine)gold (I) halogenides with diphosphines. With bis (dimethyl-phosphino)methane (DMPM), 1,2-bis(dimethylphosphino)ethane (DMPE) and 1,3-bis(dimethylphosphino)propane (DMPP) we obtained the following 8-, 10-and 12-membered annular binuclear complexes: [Au(DMPM)]2Cl2 H2O, [Au(DMPM)]2(SbF6)2, [Au(DMPE)]2Cl2 2H2O, [Au(DMPE)]2(SbF6)2, [Au-(DMPP)]2Cl2 and [Au(DMPP)]2(SbF6)2 as identified by conductivity measurements, 1H- and 31P-NMR. spectra and extinction curves. Their absorption spectra differ from those of the isolated linear PAuP-complexes mainly by a very strong band at low energy which is absent in the latter. There is a strong interaction between the PAuP-entities only in certain excited electronic states and an understanding of all transitions is only possible, if both chromophores PAuP and (PAuP)2 are taken as a basis of interpretation. Bands of the same spectrum belong apparently to two different electronic systems.The absorption spectra of isolated linear and annular ylide-complexes containing one and two CAuC-entities, respectively, show quite the same behaviour.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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