Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Chemistry  (14)
  • Excitation-Contraction  (1)
  • Holter monitoring; arrhythmia  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Carvedilol versus verapamil in chronic stable angina: a multicentre trial (1997)
    Springer
    European journal of clinical pharmacology 52 (1997), S. 95-100 
    Details
    ISSN: 1432-1041
    Keywords: Key words Chronic stable angina ; Carvedilol ; Verapamil; exercise testing ; Holter monitoring; arrhythmia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objective: In a multicentre, double-blind, parallel group study, the anti-anginal and the anti-ischaemic efficacy of 12 weeks of therapy with the vasodilating β-adrenoceptor-blocker carvedilol 25 mg b.i.d. was compared with verapamil 120 mg t.i.d. Methods: During a 2-week placebo run-in period, patients were required to have two treadmill exercise tests (modified Bruce Protocol) differing by not more than 15% with regard to total exercise time (TET). Of 313 patients enrolled, 248 were randomized and 212 completed the study according to the protocol. Results: The primary variable TET was analysed using the Cox Proportional Hazards Model to take into account censored values due to the patient stopping the exercise test for reasons other than angina. Forty-three per cent of patients allocated to carvedilol and 36% to verapamil did not stop with angina at the final visit. There was no difference in the TET between the groups, the risk ratio being 1.14 in favour of carvedilol (90% CI 0.85–1.52). TET increased from 378 s at baseline to 436 s at the final visit in the carvedilol group and from 386 to 438 s in the verapamil group. Results for time to angina and time to 1 mm ST-segment depression were similar. Compared to verapamil, carvedilol significantly reduced HR, systolic BP and rate pressure product at peak exercise. Analysis of 48 h Holter monitor data showed a greater reduction of HR and PVCs with carvedilol. Lown grading improved in both groups. Adverse events were reported by 48% (3.2% serious adverse events) of patients taking carvedilol and 58% (5.7% serious adverse events) taking verapamil. Conclusion: Carvedilol is at least as effective as verapamil in the management of chronic stable angina and demonstrated a favourable adverse event profile.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050256
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Functional and ionic changes accompanying magnesium penetration in skeletal muscle (1974)
    Springer
    Pflügers Archiv 350 (1974), S. 321-334 
    Details
    ISSN: 1432-2013
    Keywords: Skeletal Muscle ; Contractility ; Magnesium ; Calcium ; Excitation-Contraction ; Coupling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The penetration of magnesium from high-Mg Ringer's solution into skeletal muscle, and accompanying effects on intrafibre electrolyte composition, muscle contractility and Ca-exchange have been studied in isolated preparations of whole sartorius ofRana temporaria. Muscle magnesium, corrected for extracellular space, rose rapidly and then more slowly, and at 60 min in 20 mM Mg-Ringer it was calculated that intrafibre unbound Mg was increased by at least two-fold over the level in companion muscles in normal Ringer. Contractile response to direct, supramaximal stimulation was reduced in Mg-loaded muscles while resting membrane potential (E m) remained unaffected. Contracture in response to high-K was diminished while caffeine contracture was not changed. Muscles loaded with Mg also showed significant loss of fibre K and gained Na. Mg-loading caused a significant decrease in exchangeability of muscle Ca. Three fractions of exchangeable Ca in muscle were detected, characterised by half-times of circa 1.5, 7 and 50 min, respectively. In muscles soaked in high-Mg Ringer the half-times for these fractions were not different to the controls, but the quantities exchanged in the two slower fractions were reduced.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00592640
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    An investigation of radiation-induced structural changes in nitrile rubber (1996)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 34 (1996), S. 2439-2454 
    Details
    ISSN: 0887-624X
    Keywords: radiation ; nitrile rubber ; NMR ; ESR ; radicals ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mechanism of radiation-induced structural changes in nitrile rubber with different acrylonitrile contents were investigated by ESR, NMR, and FTIR. To investigate new structures solid-state NMR methods had to be used due to crosslinking of the irradiated rubbers, and higher probe temperatures were used to obtain better resolution. The radicals generated on the acrylonitrile groups were found to abstract hydrogen from the adjacent butadiene units resulting in the formation of allylic radicals. These allylic radicals reacted to form intermolecular crosslinks and cyclisation. Cyclisation of the butadiene units were found to occur in the initial stages of the irradiation. Radiation yields of radicals increased with acrylonitrile content from 1.42, 1.58, to 2.42 for 18, 30, and 45% acrylonitrile rubbers. The radiation yields for intermolecular crosslinking were higher in rubbers with higher acrylonitrile contents, giving G values of 17.8, 21.3, and 24.5 for 18, 30, and 45% acrylonitrile rubbers, respectively. However, the crosslink clustering was found to be less in the rubbers with a higher acrylonitrile content. © 1996 John Wiley & Sons, Inc.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 4
    Electronic Resource
    Electronic Resource
    Effects of gamma radiation on two aromatic polysulfones. II. A comparison of irradiation at various temperatures in air-vacuum environmentsPresented in part at the First Chemical Congress of the North American Continent, Mexico City, December 1975. (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 23 (1979), S. 2763-2775 
    Details
    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 aromatic polysulfone poly(oxy-1,4-phenylenesulfonyl-1,4-phenyleneoxy-1,4-phenyleneiso-propylidene-1,4-phenylene) (I) showed no change in flexural yield strength after doses of γ-radiation up to 600 Mrad in vacuum at 35,80, and 125°C (Tg = 190°C)). However, the flexural strength decreased markedly with doses above 100 Mrad on irradiation in air, to 40-60% of the initial value after 200-400 Mrad, depending on the sample and the irradiation conditions. Chain crosslinking was predominant over scission for irradiation in vacuum at all temperatures; (G(X), G(S), and G(S)/G(X) increased with the irradiation temperature, but G(S)/G(X) decreased to zero above Tg. Poly(oxy-1,4-phenylenesulfonyl-1,4-phenylene) (II) behaved similarly, except that the flexural strength was found to be very dependent on the thermal treatment of the sample. This polymer showed a remarkable retention of its mechanical properties on irradiation up to 200°C (Tg = 230°C) in the absence of air, the flexural strength being retained up to 500 Mrad. Radiation annealing occurred at 35°C in vacuum and air and combined radiation and thermal annealing at 125 and 220°C. Progressive removal of surface layers from flexural test bars of I irradiated in air showed that the decrease in flexural strength with dose could be explained by a decrease in the molecular weight towards the surface resulting from radiation-oxidation reactions.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1979.070230921
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Development of wear-resistant thermoplastic polyurethanes by blending with poly(dimethyl siloxane). I. Physical properties (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 61 (1996), S. 1757-1766 
    Details
    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: Commercial thermoplastic polyurethanes have been melt blended on a standard laboratory extruder with low levels of commercial poly(dimethyl siloxane) fluid. The resultant polyurethanes show improvements in wear resistance of up to 25% (c.f. virgin polyurethane) for an optimal PDMS concentration of 1.5-2.0%, beyond which the properties diminish rapidly. Unexpectedly, the mechanical properties of the blends (as measured by an Instron tensile testing machine) have been even more significantly enhanced, by up to 40% for tensile strength and 50% for elongation to break. Surface studies of the blends are also reported for x-ray photoelectron spectroscopy (XPS), contact angles and coefficient of friction (CoF). © 1996 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 6
    Electronic Resource
    Electronic Resource
    Mechanism of radiation vulcanization of natural rubber latex sensitized by monoacrylates (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 57 (1995), S. 1155-1171 
    Details
    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 mechanism of radiation vulcanization of natural rubber with 2-ethyl hexyl acrylate (2EHA) monomer was investigated using electron spin resonance spectroscopy and nuclear magnetic resonance (NMR) spectroscopy. The primary radicals formed in the arcylate molecule were found to abstract the allylic hydrogens of the polyisoprene. Crossliking may occur through the allylic radicals and/or main chain radicals formed on the polyacrylate. Acrylate was found to concentrate in the rigid regions of the crosslinked rubber indicating heterogeneity and a nonuniform distribution of the acrylate in the latex particles. The addition of the acrylate and the irradiation seems to effect the Brownian motion of the latex particles. Both the viscosity and the NMR peak widths are effected by the irradiation. Addition of 5% 2EHA increases the crosslinking by a factor of 3.6. The thermal stability of the rubber first increases with the dose in the presence of acrylate, but drops at higher doses due to peroxide formation. © 1995 John Wiley & Sons, Inc.
    Additional Material: 22 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1995.070571002
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Degradation of polystyrene by gamma irradiation: Effect of air on the radiation-induced changes in mechanical and molecular properties (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 24 (1979), S. 425-439 
    Details
    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: Irradiation of 3 mm polystyrene sheet in air at 30°C with γ rays caused a rapid decrease in the tensile and flexural strengths and strains to fracture. These properties were decreased to 50% of their initial values after ca. 80 Mrads and to 25% after ca. 200 Mrads, beyond which dose the rate of change was relatively small. These results contrast with the negligible changes that are observed after 600 Mrads in vacuum. The effect of irradiation in air has been correlated with decreasing molecular weight at the surface, even though crosslinking predominated over the complete sample so that a gel point was reached at a dose slightly in excess of 100 Mrads. Scission and crosslinking yields, G(S) and G(X), were determined as a function of depth by gel permeation chromatography of layers removed progressively from the surface. G(S) decreased and G(X) increased with depth, in accord with the concepts of increased scission by reaction with oxygen and a diffusion effect. Unusual transverse cracking to a limited depth occurred during tensile measurements, a phenomenon that is attributed to the nonuniform molecular weight profile.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1979.070240211
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Radiation degradation of polystyrene/poly(methyl methacrylate) blends (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 24 (1979), S. 2415-2418 
    Details
    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
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1979.070241210
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Effects of gamma radiation on two aromatic polysulfones (1975)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 19 (1975), S. 405-417 
    Details
    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: Two aromatic polysulfones, poly(oxy-1,4-phenylenesulfonyl-1,4-phenyleneoxy-1,4-phenyleneisopropylidene-1,4-phenylene) (I) and poly (oxy-1,4-phenylenesulfonyl-1,4-phenylene) (II), undergo crosslinking and chain scission at 30°C during γ-irradiation, the former being predominant in vacuum and the latter in air. Both processes occurred more readily in I, which contains isopropylidene linkages. Gel measurements gave G(crosslink) = 0.051, G(scission) = 0.012 for this polymer at 30°C in vacuum. Increased irradiation temperatures resulted in higher crosslinking and gas yields, especially above the glass transition temperature. The tensile strength, flexural strength, and modulus of I were unaffected by γ-irradiation up to about 50 Mrad in air, but the strength decreased markedly at higher doses. The elongation at break decreased progressively with dose. For both polymers, G(gas) = 0.04 at 30°C with the main products being SO2, H2, CO2, CH4, and H2O.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1975.070190208
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Vinyl acetate emulsion polymerizationTaken in part from the thesis of J. T. O'Donnell, submitted June 1956 in partial fulfillment of the requirements for the Master of Science degree at the Polytechnic Institute of Brooklyn. (1958)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 28 (1958), S. 171-177 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Vinyl acetate emulsion polymerization at 70°C. using potassium peroxydisulfate as initiator and a partially hydrolyzed polyvinyl acetate as emulsifying agent has been studied. In agreement with the Smith and Ewart scheme for emulsion polymerizations, the polymerization rate was found to be independent of the total monomer amount present and approximately dependent on the 3/5 power of the emulsifier concentration. Instead of a 2/5 power dependence on initiator concentration for the rate of polymerization, a 0.7 power dependence was found. From surface tension measurements an “apparent critical micelle concentration” was determined for aqueous solutions of the emulsifier. However, light scattering studies gave no indication that aggregates of the emulsifier exist in aqueous solutions.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1958.1202811615
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...