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  • Physics  (2)
  • Polysilane  (2)
  • Arousal  (1)
  • Cigarette  (1)
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  • 1
    Digitale Medien
    Digitale Medien
    Properties of some polysilane polymers: (n-PrSiMe) n , (i-PrSiMe) n , and (sec-BuSiMe) n (1995)
    Springer
    Journal of inorganic and organometallic polymers and materials 5 (1995), S. 31-42 
    Details
    ISSN: 1572-8870
    Schlagwort(e): Polysilane ; nematic mesophase ; liquid crystal ; isotopic phase ; thermochromic transition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Three polysilane polymers, (n-PrSiMe) n , (i-PrSiMe) n , and (sec-BuSiMe) n , were synthesized and characterized by DSC. UV spectroscopy, wide-angle X-ray diffraction, and optical microscopy, all at variable temperatures. The known thermochromic transition of (n-PrSiMe) n at ∼48 C is associated with a change from an orthorhombic to an isotropic phase. (i-PrSiMe) n was examned as an insoluble and soluble (lowM w) fraction, both existing mainly in an orthohombic lattice at room temperature. (sec-BuSiMe) n has a mesophase structure at 25 C, undergoes a weak endothermic transition to a second (nematic) mesophase near 65 C, and becomes isotropic at ∼160 C.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01157521
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  • 2
    Digitale Medien
    Digitale Medien
    Synthesis and characterization of alternating silane copolymers: (Me2Si−R2Si−Me2Si) n (1995)
    Springer
    Journal of inorganic and organometallic polymers and materials 5 (1995), S. 217-236 
    Details
    ISSN: 1572-8870
    Schlagwort(e): Polysilane ; NMR ; pyrolysis ; randomization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Bimodal molecular weight distributions of alternating copolymers of the type (Me2Si−R2Si−SiMe2) n , where R=hexyl and butyl, were obtained by polymerization of BrSiMe2−R2Si−Me2SiBr, using the Wurtz coupling method. Analysis of the samples by pyrolysis GC MS and solution29Si NMR indicated that some randomization occurred, due to cleavage of the original Si−Si bonds in the monomer. The extent of randomization was significantly greater in the high molecular weight fractions. Based on the nature of the rings from the py MGC/MS traces and the number on nonads found in the29Si spectra, two types of randomization processes have been proposed, involving backbiting followed by (1) ring expulsion or (2) redistribution.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01057894
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  • 3
    Digitale Medien
    Digitale Medien
    Pre-abstinence smoke intake and smoking motivation as predictors of severity of cigarette withdrawal symptoms (1985)
    Springer
    Psychopharmacology 87 (1985), S. 334-336 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Withdrawal ; Cigarette ; Nicotine ; Dependence ; Motivation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Twenty-nine cigarette smokers completed a smoking motivation questionnaire and had expired-air carbon monoxide (CO) and plasma nicotine concentrations measured prior to abstaining from smoking for 24 h. Before and after the abstinence period, the subjects rated mood and physical symptoms known to be affected by cigarette abstinence (e.g. irritability, restlessness). Scores on the “dependent smoking” subscale of the smoking motivation questionnaire correlated significantly with overall withdrawal severity, craving, and increased irritability. “Indulgent smoking” scores correlated positively with increased hunger. Pre-abstinence plasma nicotine concentration significantly pedicted craving, hunger, restlessness, inability to concentrate and overall withdrawal severity, while expired-air CO predicted craving and restlessness only. Usual daily cigarette consumption did not significantly predict any withdrawal effects. The data indicate that pre-abstinence measures of smoking motivation and smoke intake may provide a guide to withdrawal severity on smoking cessation and that smokers with a high pre-abstinence nicotine intake experience the greatest discomfort.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00432717
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  • 4
    Digitale Medien
    Digitale Medien
    Function of cigarette smoking in relation to examinations (1992)
    Springer
    Psychopharmacology 108 (1992), S. 456-459 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Smoking ; Nicotine ; Examination anxiety ; Stress ; Arousal
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Eighty-two college students took part in a study on motives underlying increases in cigarette smoking prior to examinations. One group was tested a month before, and a second group was tested the day before, the start of examinations. Measures were taken of current cigarette consumption, general anxiety, anxiety about forthcoming exams, the importance of sedative and stimulant smoking motives, hours spent revising and in other activities and amount smoked during these activities. The results indicated that the students increased the hours they spent revising and there was a corresponding increase in the number of cigarettes smoked during this activity. They also reported an increase in the importance of stimulant smoking motives. Anxiety levels increased in the run up to exams but there was no increase in sedative smoking motives. The results raise the issue of whether any anxiolytic action of nicotine may be limited to acute stressors and also whether smokers' use of cigarettes to help them stay alert during revision translates into improved examination performance.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02247421
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  • 5
    Digitale Medien
    Digitale Medien
    Organosilane polymers: Formable copolymers that contain methyl(β-phenethyl)silylene or cyclohexyl(methyl)silylene units (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 225-238 
    Details
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 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.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pol.1984.170220121
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  • 6
    Digitale Medien
    Digitale Medien
    Organosilane polymers: Formable copolymers containing dimethylsilylene units (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 159-170 
    Details
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Formable silane copolymers that contain dimethylsilylene units were synthesized and characterized. These polymers have high molecular weights and appreciable solubility in common solvents, can be molded or cast into films or drawn into fibers, and are photoactive.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pol.1984.170220116
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