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  • 1
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biochimica et Biophysica Acta (BBA)/General Subjects 674 (1981), S. 160-165 
    ISSN: 0304-4165
    Keywords: (Rat anterior pituitary membrane) ; Agonist specificity ; Guanine nucleotide ; Muscarinic cholinergic receptor
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine , Physics
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Inflammation research 45 (1996), S. 531-540 
    ISSN: 1420-908X
    Keywords: Antiinflammatory ; Analgesic ; Antipyretic ; pKa ; Octanol-water partition coefficient ; NSAIDs ; Animal models ; Carrageenin ED50
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objective and Design: Relevance of the preclinical pharmacodynamic, toxicity and pharmacokinetic parameters predicting the clinical potency of nonsteroidal antiinflammatory drugs (NSAIDs) was evaluated. Material: Data for oral potencies of 24 NSAIDs in rats were collected from the literature and from New Drug Applications with respect to the following parameters: antiinflammatory, analgesic, antipyretic, acute ulcerogenic activities, acute toxicity, in vitro inhibition of prostaglandin synthesis, acid dissociation constant (pKa), octanolwater partition coefficient and elimination half-life. Treatment: Data for most of the in vivo parameters in rats were collected following single dose administration with the exception of adjuvant arthritis. Single and daily clinical doses were considered. All of these NSAIDs have been approved for marketing although not all have been sold in the USA. Methods: The preclinical data were compared to human dose (unit or daily doses) using single and multiple stepwise regression analyses. Results: Analyses suggest that NSAIDs are effective in all models of preclinical tests for fever, pain and inflammation, however, carrageenin-induced rat paw edema model is clearly the best predictor of human dose. Rank order of preclinical models for predicting human dose is carrageenin 〉yeast induced fever〉pressure induced pain=adjuvant arthritis in rats. The analysis suggested that the pain and adjuvant arthritis models in rats may also involve a prostaglandin independent mechanism. Of the two physicochemical factors tested, pKa contributed best to the carrageenin model towards predicting the clinical potency of NSAIDs. Mathematical relationships between human dose, carrageenin ED50 and pKa were established that may assist in the future clinical development of NSAIDs. Conclusions: Carrageenin-induced paw edema model in rats is the most robust predictor of the clinical potency of NSAIDs. Acid dissociation constant (pKa) appears to be a secondary contributor to the potency of NSAIDs. The relevance of the data analyses for developing cyclooxygenase-2 (COX-2) selective NSAIDs is discussed.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 173 (1989), S. 205-212 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Herkömmliches Vernetzen von Polyethylen niedriger Dichte (LDPE) wurde mit Dicumylperoxid (DCP) als Vernetzer durchgeführt. DCP wurde in verschiedenen Konzentrationen mit LDPE-Schnitzeln in einem Extruder bei 135 - 145°C gemischt. Monofilamentfäden wurden bei 110°C auf einer Laborziehmaschine gezogen. Die Zugdehnungseigenschaften, der prozentuale Schrumpf und die Dichte wurden mit Zunahme der DCP-Konzentration und der Heizdauer verbessert, während jedoch die prozentuale Quellung abnahm.
    Notes: Conventional crosslinking of low density polyethylene (LDPE) was carried out using dicumyl peroxide (DCP) as crosslinking agent. DCP in various concentrations was mixed with LDPE chips in an extruder at 135 - 145°C. Monofilaments were drawn on a laboratory drawing machine at 110°C. It was found that tensile properties, percent shrinkage and density were improved with the increase in the concentration of DCP and in the heating period, whereas, however, the percent swelling decreased.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 163 (1988), S. 23-35 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Chlorierung von ataktischem Polypropylen (APP) wurde thermisch gestartet und in Tetrachlorkohlenstoff durchgeführt. Es wurde gefunden, daß mit zunehmender Verdünnung der Chlorierungsgrad steigt, was in % Gewichtszunahme gemessen wurde. Grund für dieses Verhalten ist eine größere Aufweitung und Beweglichkeit der APP-Ketten, wodurch die durch Chlor zu ersetzenden Stellen besser zugänglich werden. Die Reaktionsordnung in Abhängigkeit von der APP-Konzentration beträgt 0,84 und die Aktivierungsenergie (Er) 5,29 kcal/mol. Die Erhöhung der Strömungsrate führt zu einem höheren Chlorierungsgrad. Dieser steigt bis zu einer Strömungsrate von 1 l/h linear an, um dann ein konstantes Nivoau anzustreben. IR-Spektroskopie und 13C-NMR-Untersuchungen weisen darauf hin, daß die Chlorierung an allen drei ersetzbaren H-Atomtypen vorkommt. Der Startschritt des Mechanismus ist wahrscheinlich die Substitution des tertiären H-Atoms durch freie Chlorradikale und nachfolgendem Austausch der sekundären und primären H-Atome durch entweder fortschreitende Substitution oder den Eliminierungs-Additions-Mechanismus.
    Notes: Chlorination of atactic polypropylene (APP) was thermally initiated and carried out in carbon tetrachloride (CCl4) solution. It was found that with the increase in dilution, there is an increase in the extent of chlorination, as measured in terms of % weight-gain. The reason for this behaviour has been ascribed to a greater degree of opening up and mobility of APP chains thus increasing the accessibility of the replaceable sites to chlorine. The order of the reaction with respect to APP concentration was found to be 0.84, the overall activation energy (Er) being 5.29 kcal/mol. Increase in flow rate leads to an increase in the extent of chlorination and was found to be increasing linearly with a flow rate up to 1 l/h beyond which it levels off. IR spectroscopy and 13C-NMR studies indicate the chlorination occurring in all the three types of replaceable H-atoms in APP. The mechanism appears to be initial substitution of tertiary H-atom by free chlorine radical followed subsequently by replacement of secondary and primary H-atoms via either progressive substitution or elimination-addition mechanism.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 17 (1994), S. 422-429 
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Affinity chromatography (biospecific adsorption) relies on specific interactions of biological molecules such as enzymes, antigens, antibodies, and proteins. The process consists of three steps: adsorption, washing, and elution. A mathematical model including convection, diffusion, and reversible reaction is formulated to analyse the breakthrough behaviour of the solute. A moving finite element orthogonal collocation method is applied with respect to the space variables of the governing partial differential equations of the model to evaluate the breakthrough of the solute. Danckwerts' boundary conditions are considered for the column. The validity of the numerical scheme is checked by comparison with an analytical solution for a simplified model. The results obtained from model simulation show that the breakthrough time of the solute is significantly influenced by the axial dispersion coefficient, solute concentration, ligand content, reaction kinetics, particle porosity, particle size, and flow rate. Solute recovery and bed utilisation efficiencies are evaluated for different values of the above parameters.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 171 (1989), S. 131-139 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Es wurden Molekulargewichtsuntersuchungen an chloriertem, ataktischem Polypropylen, das durch Chlorierung von ataktischem Polypropylen hergestellt wurde, mit Hilfe von Viskositätsmessungen und Gelpermeationgschromatographie durchgeführt. Die Grenzviskositätszahl, das zahlenmittlere Molekulargewicht (Mn) und das gewichtsmittlere Molekulargewicht (Mw) hängen sowohl vom Chlorierungsgrad als auch von den Synthesebedingungen ab. Die beobachteten Phänomene werden diskutiert.
    Notes: Molecular weight studies of chlorinated atactic polypropylene (CAPP), prepared by thermal chlorination of atactic polypropylene (APP), have been carried out by viscosity measurements and gel permeation chromatography. In general, the intrinsic viscosity [η], number average molecular weight (Mn) and weight average molecular weight (Mw) are dependent on degree of chlorination as well as synthesis conditions. The phenomena observed are discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 161 (1988), S. 77-87 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Monfilamente von Polyethylen niederer Dichte mit unterschiedlichem Verstreckungsgrad wurden der Strahlung einer Co60-Gammastrahlenquelle unterworfen. Es zeigte sich, daß die Zugfestigkeit mit ansteigender Strahlungsdosis bis 20 Mrd stark verbessert wird, oberhalb dieser Dosis wird eine scharfe Abnahme der Reißfestigkeit und des Anfangsmoduls beobachtet. Die Quellung nahm ebenfalls mit zunehmender Strahlungsdosis ab. Jedoch zeigte die Dichte einen ansteigenden Trend. Der Schrumpf nahm bei allen Filamenten mit steigender Strahlungsdosis und Verstreckungsgrad zu. Die Ergebnisse wurden als Zunahme der Vernetzungsdichte mit zunehmender Strahlungsdosis erklärt, bei gleichzeitiger Abnahme der Kristallinität, die in fortgeschritteneren Bestrahlungsstadien stärker wird. Die Proben zeigten einen Memory-Effekt nach Verstreckung bie 110°C, Abkühlen unter Spannung, gefolgt von abermaligem Aufheize auf 110°C in entspannter Form. Der Schrumpf war noch immer viel größer, aber unabhängig vom Verstreckungsgard.
    Notes: Low density monofilaments of polyethylene with varying draw ratios were subjected to high energy radiation using Co60 gamma radiation source. It was found that the tensile strength is sharply improved with the increasing dose up to 20 Mrd beyond which a sharp decrease in tenacity and initial modulus was observed. The swelling behaviour also decreased with the increased in dose of irradiation. However, density showed an increasing trend. The shrinkage behaviour of all the filaments was found to increase with increasing dose and draw ratios. The results have been explained in terms of continuous increase in crosslink density with the increasing dose of irradiation along with loss of crystallinity, which appears to be more severe in the latter stages of exposure. The samples exhibited memory effect after redrawing at 100°C and cooling under tension followed by further heating at 110°C under relaxed condition. The shrinkage was still much higher but independent of draw ratio.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 44 (1992), S. 773-779 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Thermal behavior of brominated atactic polypropylene (BAPP), obtained by thermal bromination of atactic polypropylene (APP), was evaluated by thermogravimetric analysis (TGA) and differential thermal analysis (DTA). It was found that the initial decomposition temperature (IDT) and char yield increase with the increase in bromine content while integral procedural decomposition temperature (IPDT) showed a decreasing trend. A comparative study of these value in inert and oxidative atmospheres has been made. DTA study shows that onset decomposition temperature (ODT) and glass transition temperature (Tg) increase with the increase in degree of bromination. The possible reasons for the occurring phenomena have been discussed.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 44 (1992), S. 233-238 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Glycidyl methacrylate and N-vinyl pyrrolidone have been grafted onto natural rubber at 32°C using the simultaneous cobalt-60 irradiation technique. The natural rubber samples were swollen in the monomers for 24 h and thereafter subjected to gamma irradiation. The homopolymers formed in the graft copolymerization reactions and unreacted monomer were removed by solvent extraction using acetone and methanol for glycidyl methacrylate and N-vinyl pyrrolidone monomer, respectively. The influence of total dose and monomer concentration on the graft parameters was investigated. The dependence of the rate of grafting on the monomer concentration was found to be 0.93 and 0.80 for glycidyl methacrylate and N-vinyl pyrrolidone, respectively. DSC and TGA studies of the polymers were undertaken. Grafted copolymers based on glycidyl methacrylate were relatively less thermally stable compared with ungrafted natural rubber.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 39 (1990), S. 1485-1493 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The electrical properties, such as dielectric properties and volume resistivity, of chlorinated atactic polypropylene(CAPP), obtained by thermal chlorination of APP, have been studied. The results show that dielectric constant, loss tangent, and volume resistivity of the chlorinated samples increase with the increase in degree of chlorination. The effect of CAPP as secondary plasticizer in the PVC-DOP system has also been studied. Dielectric study of PVC compounds shows a single relaxation peak, indicating no phase separation. In the case of PVC compounds, it has been observed that with the increase in CAPP content in PVC compounds dielectric constant and loss tangent decrease whereas volume resistivity increases. The increase in volume resistivity was further supported by the increase in activation energy value, obtained from volume resistivity vs. 1/T plot.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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