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  • 1990-1994  (6)
  • 1980-1984  (5)
  • Polymer and Materials Science  (5)
  • Sex pheromone  (3)
  • reperfusion  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Digestive diseases and sciences 35 (1990), S. 1397-1402 
    ISSN: 1573-2568
    Keywords: tissue viability ; ATP ; EC ; reperfusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The hepatic artery and the portal vein blood vary in flow, oxygenation, and hormonal content. It was uncertain which blood supply has a greater effect on the recuperative process of the hepatocytes in the ischemic liver during the initial reperfusion. The ability of the liver cells to restore its energy phosphates is related to the viability of the liver. This study was designed to determine the differences of the high energy phosphate in the liver predicated upon whether reflow was first provided by either the hepatic artery or the portal vein followed by subsequent reperfusion from both vessels. The recovery of ATP upon 10 min of only hepatic arterial reperfusion after 15 min of total ischemia was much slower compared to the portal venous reperfusion only. It may be undesirable, therefore, to reperfuse the liver with hepatic arterial blood first immediately after warm liver ischemia.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 8 (1982), S. 95-114 
    ISSN: 1573-1561
    Keywords: Sex pheromone ; Tenthredinidae ; Pikonema alaskensis ; hydrocarbons ; dienes ; synergists ; experimental design ; ozonolysis ; mass spectra ; methoxymercuration ; Hymenoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The primary sex pheromone of the yellowheaded spruce sawfly,Pikonema alaskensis (Rohwer) (Hymenoptera: Tenthredinidae), was found to include a series of straight-chain hydrocarbon dienes, all with the double bonds in the 9 and 19 positions and all with the (Z, Z) configuration. The major components, of 29, 31, 33, 35, and 37 carbon atoms, were synthesized. In the field and the greenhouse, the synthetic dienes were far above control levels in activity but, at least during the first hours of bioassay, were somewhat less active than the female-derived materials on a weight basis. In the field, a mixture of all five synthetic dienes, in the proportions found in the females, was more attractive than any single one, on a mole basis. In addition, (Z, Z)-9,19 dienes of 28, 30, 32, 34, 36, 38, and 39 carbons have been detected in females in minor amounts. The first five were bioassayed, and each was found to be similar in activity to the 35-carbon component when compared on a weight basis. The synthetic dienes, while active by themselves, were strongly synergized by two, more polar, Florisil fractions derived from females. Experimental design considerations are discussed.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 8 (1982), S. 83-94 
    ISSN: 1573-1561
    Keywords: Sex pheromone ; bioassay ; synergism ; sawfly ; Hymenoptera Tenthredinidae ; Pikonema alaskensis ; experimental design
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The existence of a female-produced sex pheromone in the yellowheaded spruce sawfly,Pikonema alaskensis (Rohwer) (Hymenoptera: Tenthredinidae) was demonstrated by field and greenhouse bioassays. Virgin females, their empty cocoons (with which they were confined during handling procedures), and the hexane extract of these cocoons were attractive in the field. The only Florisil fraction of this extract consistently attractive by itself was that eluted with hexane, but three, more polar fractions (eluted with 5%, 25%, and 50% ether in hexane) each synergized the hexane fraction, increasing bioassay responses 10–30 times. Fractions derived directly from virgin females yielded comparable results. The greenhouse data corroborated the field data, except that the 5% ether-hexane fraction, while very synergistic in the field, was consistently inactive in the greenhouse.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Basic research in cardiology 87 (1992), S. 19-26 
    ISSN: 1435-1803
    Keywords: Protein kinase C ; myocardium ; ischemia ; calmodulin-dependentkinase ; reperfusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The protein kinase activity in cytosol was similar in control, ischemic, and reperfused hearts; however, a 1.5-fold increase in membrane protein kinase activity was induced by ischemia and reperfusion. The H-7 inhibitable cytosolic protein kinase activity decreased by 40% with 30 min ischemia, while that of membrane fraction increased 1.8-fold. However, the CGS9343B inhibitable protein kinase activity in cytosolic fractions was unaffected by ischemia, while that of membrane increased by about 1.7-fold. These results suggest that myocardial ischemia is associated with enhanced protein kinase C and calmodulin-dependent kinase activities in membrane fraction. Furthermore, the results also suggest a translocation of protein kinase C activity from the cytosol to the membrane. Reperfusion of ischemic myocardium did not result in any further increase of protein kinase C and calmodulin-dependent kinase activities in the membrane. These enhanced protein kinase activities also resulted in an enhanced phosphorylation of endogenous membrane proteins. The creatine kinase released from the heart was increased by both ischemia and reperfusion. Therefore, these results suggest that biochemical cascades of reactions caused by enhanced membrane protein kinase C and calmodulin-dependent kinase activities may contribute to ischemic-reperfusion injury.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Basic research in cardiology 87 (1992), S. 527-535 
    ISSN: 1435-1803
    Keywords: Myocardialstunning ; lipids ; phospholipidbilayer ; reperfusion ; adaptation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Recent studies indicate that preconditioning of the heart by repeated stunning protects it from subsequent ischemic injury. Such myocardial preservation is likely to be due to adaptive modification of lipid composition and dynamic structure of cellular membrane. To test this hypothesis, swine heart was subjected to four episodes of 5 min stunning by LAD occlusion, followed by 10 min of reperfusion after each stunning. The heart was then made regionally ischemic for 60 min by LAD occlusion, followed by 6 h reperfusion. A control heart was perfused for 60 min, followed by 60 min ischemia and 6 h reperfusion. Free fatty acids (FFA) accumulated in the control heart during ischemia, as expected, which was further enhanced by reperfusion. The FFA level was also enhanced during ischemia in stunned myocardium. However, this FFA level was almost restored during reperfusion. The levels of unsaturated fatty acids (UFA) such as oleate, linoleate, and arachidonate followed a similar pattern. Membrane fluidity, monitored by fluorescence polarization, was decreased during ischemia and reperfusion in the unstunned heart, with the corresponding increase in microviscosity. The increased microviscosity was significantly reduced by stunning. Since FFA are presumably generated from membrane phospholipids, these results suggest that stunning may cause the incorporation of a grater proportion of PUFA in membrane phospholipids, leading to preservation of membrane phospholipids and maintaining the membrane fluidity, which may be at least partially reponsible for the attenuation of ischemic reperfusion injury.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 10 (1984), S. 291-300 
    ISSN: 1573-1561
    Keywords: Sex pheromone ; Hymenoptera ; Ichneumonidae ; Syndipnus rubiginosus ; ethyl (Z)-9-hexadecenoate ; parasitoid ; Pikonema alaskensis ; mass spectra ; ozonolysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A female-produced sex pheromone ofSyndipnus rubiginosus Walley (Hymenoptera: Ichneumonidae), a parasitoid of the yellowheaded spruce sawfly,Pikonema alaskensis (Rohwer) (Hymenoptera: Tenthredinidae), was isolated and identified from hexane extracts of 250 virgin females. Column chromatography (Florisil), gas chromatography, mass spectrometry, high performance liquid chromatography, and ozonolysis indicated the structure was ethyl (Z)-9-hexadecenoate. The optimum male response is at 300–1000 ng (3–10FE). No cross-attraction betweenS. rubiginosus and the sympatric sawfly parasitoidS. gaspesianus (Provancher) could be demonstrated.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 31 (1993), S. 807-819 
    ISSN: 0887-6266
    Keywords: polyethylene, polyene formation on irradiation with acetylene present in ; polyene formation in irradiation of polyethylene with acetylene present ; crosslinking in polyethylene irradiated with acetylene present ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Electron-spin resonance (ESR) and altraviolet (UV) visible spectroscopic evidence has been found for the formation of diene, triene and tetraene, following the irradiation of polyethylene in the presence of acetylene. The polyenes are formed by a mechanism which is different from that observed under vacuum or with inert gas saturation. The sum of the G (polyene) values obtained by UV spectroscopy is almost half that of initial radical formation. It is concluded that polyene bridges, predominantly diene, form crosslinks between radical pairs. G (X) values determined from gel fraction data, using Saito-Kang-Dole theory, are found to be greatly in error and misrepresentative of crosslink changes. © 1993 John Wiley & Sons, Inc.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 32 (1994), S. 469-479 
    ISSN: 0887-6266
    Keywords: polyethylene ; acetylene ; FTIR ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Interchain bridges of unsaturated double bonds have been proposed to form in amorphous regions, when polyethylene is irradiated in the presence of acetylene. We have corroborated the formation of these bridges by infrared spectroscopic studies. The double bonds are composed mainly of trans-olefin and vinyl end groups, formed as a result of competing radical-radical termination and hydrogen atom abstraction reactions. The hydrogen atom abstraction reaction becomes insignificant in uniaxially oriented high-density polyethylene having a draw ratio of 7.5, because of the alignment and positioning of the initiating radical pairs. During in vacuo irradiation and annealing only in-chain trans-olefins are usually formed. © 1994 John Wiley & Sons, Inc.
    Additional Material: 4 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 45 (1992), S. 819-826 
    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 transport properties of acetylene in a high modulus polyethylene fiber have been studied in detail over the temperature range of 25 to 65°C. Diffusion coefficients for the fiber are about four orders of magnitude lower than values cited for isotropic high density polyethylene. In keeping with this, a much higher apparent activation energy of diffusion (ca. 80.64 ± 0.53 kJ mol-1) was found. The solubility of acetylene in the fiber (ca. 0.158 cm3 C2H2 STP/cm3 PE @ 76 cm Hg), is lower, but of the same order of magnitude as that expected for isotropic polyethylene. The apparent heat of solution was determined, within experimental limits, to be zero. It is concluded that the acetylene is neither chemically nor physically absorbed onto the fiber, but freely diffuses, according to Fick's law, through the amorphous regions of the polymer.
    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 25 (1980), S. 315-321 
    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: Fibers of poly(1,4-phenylene-1,3,4-oxadiazole) have been prepared by dry jet-wet spinning sulfuric acid solutions of the polymer. Polymer was prepared by polymerizing terephthalic acid and hydrazine dihydrochloride in 30% fuming sulfuric acid and directly spinning the resulting solution. Dry jet-wet spinning allows greater flexibility in conditions than does wet spinning in that spinneret temperature and coagulation bath temperature are independent of one another. Therefore, coagulation may be at temperatures well below those needed at the spinneret to maintain a flowing, extrudable solution. Another common advantage of dry jet-wet spinning is application of draw to the extruded fiber before coagulation, but in this system, drawing the fiber before coagulation was shown to be a disadvantage. Fiber properties were maximized by spinning with a spinneret temperature of 58-73°C into a coagulation bath at 3-4°C and with an air gap of 1/4 in. Water as a coagulation medium allowed operation at speeds up to 40 m/min, while with 50% sulfuric acid less than half that speed was reached. Application of draw ratios of 3/1 on the coagulated but still swollen fiber combined with high-temperature treatments at low draw ratios (1.05/l) gave maximum fiber properties-tenacity 6 g/denier, elongation 20-25%, and modulus 200-240 g/denier.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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