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  • 1
    ISSN: 0887-624X
    Keywords: phospholipid analogous acrylamide monomers ; long chain alkyl groups ; phosphatidylcholine analogues ; stacked bilayer structure ; liquid crystalline behavior ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of new phospholipid analogous acrylamide monomers (4a-e) containing long alkyl chains as hydrophobic groups and containing phosphatidylcholine analogues as hydrophilic group were synthesized in high yields. The homopolymerizations and copolymerization (4b with 4e) were carried out in the presence of a radical initiator. The structures and thermal properties of these polymers were investigated by x-ray diffraction analysis, DSC, and polarizing microscopy measurements. It has been revealed that these homopolymers (5b, 5c, and 5d) which bear saturated long-hydrocarbon chains in the side chains exhibited not only orderly stacked bilayer structures at room temperature but also clear liquid crystalline behavior within a wide temperature range. The viscosity behavior of all polymers was found similar to usual polyelectrolytes in porlar solvent. The polymers obtained were also characterized by 1H-NMR, IR, and melting point, respectively. © 1996 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 2
    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 kinds of phospholipid analogous compounds, methacrylate monomers (4a-b) and acrylamide monomers (5a-b), were prepared and polymerized with a radical initiator in water at room temperature. The viscosity behavior of these charged polymers were investigated in the presence or absence of inorganic salts, and the found inherent viscosity [η] of amide polymer (poly7a) is higher than those of ester polymers (poly6a1 and poly6b). On the other hand, the radical copolymerization of monomer 5b with acrylamide (AAm) was also carried out in water. Based on the x-ray analyses, it is proposed that some of the obtained polymers show ordered bilayer structures in condensed phase. Furthermore, the thermal properties were studied by DSC and TG-DTA measurements. © 1996 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
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  • 3
    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: Polyrethanes, based on 2-[bis(2-hydroxyethyl)methylammoni]ethylstearylphosphate, alone or together with 1,4-butanediol as the chain extender, poly(isoprene) diol and 4,4′-methylenediphenyl diisocyanate, were prepared. These segmented phospholipid polyurethanes were characterized by IR, elemental analyses, and gel permeation chromatography. The polyurethane, with both phospholipid diol and 1,4-butanediol as the chain extender, was further investigated by differential scanning calorimetry, x-ray diffraction, scanning electron microscopy, plasma contact and clotting time. An x-ray diffraction measurement for the polymer shows a intense scattering at 79.3 Å corresponding to the length of soft segments, which is hydrophobic poly(isoprene), and a weak diffuse scattering at 5.1 Å corresponding to the distance between the hydrophobic poly (isoprene) layers. The hemocompatibilities of the polymer were evaluated by platelet rich plasma contacting studies and by scanning electron microscopy using medical grade poly(vinyl chloride) as control. The hot-pressed films of the polymer exhibit a favorable surface in terms of platelet adhesion, and the morphology of adhered platelets undergoes to a relatively lower degree of variation compared to poly(vinyl chloride). Moreover, the clotting time of the polymer in contact with human platelet rich plasma was 220, 100, and 86 s for the phospholipid-based polyurethane, poly(vinyl chloride), and glass, respectively. © 1996 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
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  • 4
    ISSN: 0730-2312
    Keywords: LY294002 ; wortmannin ; signal transduction ; tyrosine kinase ; mitogen ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Studies on a platelet-derived growth factor (PDGF) responsive osteosarcoma cell line, MG-63, were initiated to determine the effects of phosphatidylinositol (Ptdlns) 3-kinase inhibitors on serum-stimulated cell proliferation and PDGF-stimulated DNA replication, actin rearrangements, or Ptdlns 3-kinase activity. In a dose-dependent manner, the fungal metabolite wortmannin and a quercetin derivative, LY294002 (2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one), inhibited serum-stimulated MG-63 cell proliferation. The mitogenic effects of PDGF on MG-63 cells, as determined by incorporation of [3H]-thymidine, were also substantially inhibited in the presence of 0.10 μM wortmannin or 10 μM LY294002. Furthermore, MG-63 cells stimulated by PDGF form distinct actin-rich, finger-like membrane projections which are completely inhibited by either 0.10 μM wortmannin or 10 μM LY294002. At these same concentrations, wortmannin and LY294002 were also effective at reducing levels of phosphatidylinositol 3-phosphate in PDGF-stimulated MG-63 cells. Treatment of these cells with increasing concentrations of wortmannin reduced the level of PDGF stimulated tyrosine phosphorylation of the PDGF receptor but did not significantly affect the amount of the Ptdlns 3-kinase regulatory subunit, p85, associated with the receptor. Additionally, pretreatment of cells with 0.250 μM wortmannin followed by stimulation with PDGF resulted in a slightly reduced level of receptor autokinase activity; however, similar treatment with 50 μM LY294002 did not affect the level of autokinase activity. These results demonstrate the effects of two different Ptdlns 3-kinase inhibitors on serum- and PDGF-stimulated MG-63 cell proliferation and PDGF-stimulated morphological changes and suggest a greater role for Ptdlns 3-kinase in these processes. J. Cell. Biochem. 64:182-195. © 1997 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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  • 5
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Two polyimides, PI(BA-TD) and PI(6FDA-TD), based on an aromatic diamine (TD) and two aromatic dianhydrides (BA, 6FDA) were synthesized. They were characterized by viscosity, FT-IR, and X-ray photoelectron spectroscopy (XPS) measurements. XPS results reveal that the binding energy of C1s, N1s, and O1s in PI(BA-TD) is lower than that in PI(6FDA-TD). The synthesized polyimides form stable and homogeneous thin films on an ITO electrode, functioning as good hole transporting materials for organic electroluminescent (EL) devices. The double-layered EL devices consisting of a hole transporting layer of these polyimides and an emitting layer of the tris(8-quinolinolato)aluminium complex exhibit a peak emission wavelength in the bright green at 521-525 nm. Furthermore, a maximum luminance of 97 cd/m2 was achieved at a voltage of 15 V with a current density of 192 mA/cm2 for the EL device using PI(BA-TD) as a hole transporting layer. The phenomenon of an extended luminance of these EL devices was also found when a voltage higher than 15 V was applied.
    Additional Material: 7 Ill.
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  • 6
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Three new amphiphilic phospholipid diols containing hydrophilic phosphatidylcholine analogues in the main chains and hydrophobic octadecyl, hexadecyl or dodecyl alkyl groups in the side chains were synthesized. The typical phospholipid diol based on an octadecyl group was further reacted with diisocyanates such as hexamethylene diisocyanate (HDI), 2,4-tolylene diisocyanate (TDI) and 4,4′-methylenediphenyl diisocyanate (MDI), respectively. Preliminary studies suggest that polyurethane based on MDI shows a viscosity behavior similar to common polyelectrolytes and exhibits a therm decomposition peak at 244°C due to the phospholipid moiety and a melting point at 218°C.
    Additional Material: 2 Ill.
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  • 7
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: New hydrophobic-hydrophilic microphase-separated block segmented copoly(urethane-urea)s were synthesized by introducing hydrophobic polybutadienes as the soft segments and 4,4′-methylenediphenyl diisocyanate, hexamethylene diisocyanate, ethylenediamine, and a hydrophilic phosphatidylcholine analogue as the hard segments in the backbones of these polymers. The results of ATR-IR and XPS show the coexistence of phosphatidylcholine analogues and polybutadienes on the surface of cast films of the synthesized poly(urethane-urea)s. Furthermore, TEM cross sectional observation of the cast film PBDP-1370 indicates that it possesses a hydrophilic-hydrophobic microphase-separated domain structure.
    Additional Material: 4 Ill.
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  • 8
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A series of phospholipid diols based on different lengths of alkyl chains such as eicosyl, stearyl, cetyl, lauryl, octyl, and butyl was synthesized and characterized. The phospholipid diols were subjected a polyaddition polymerization with hexamethylene diisocyanate. The haemocompatibilities of the resulting phospholipid polyurethanes were evaluated by platelet rich plasma contacting experiments and viewed by scanning electron microscopy. The polymers with alkyl chains of 20, 18, 16, and 12 carbon atoms showed much better haemocompatibilities than those with alkyl chains of 8 and 4 carbon atoms.
    Additional Material: 3 Ill.
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  • 9
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In this series of studies, the innervation patterns of whole-mount preparation of bicuspid and tricuspid valves were studied by light microscopy in the mouse, rat, guinea pig, and opossum. The acetylcholinesterase-positive networks of nerve fibers showed many similarities in the basic patterns of valve innervation in all of the species studied, but several interspecies variations were observed. The basal zone of the valve adjacent to the fibromuscular atrioventricular ring displayed the most dense plexus of nerves, with acetylcholinesterase-positive fibers being seen across the width of the valve. In the intermediate zone of the valve, less dense plexuses of nerve fibers were found; and these were more numerous in the cuspal areas and less numerous in the intervening commissural areas. In the distal portions of the valve, nerve networks arborized extensively, with some of their nerve fibers extending toward the chordae tendineae and the free edges of the valve cusps. Only in the guinea pig and opossum did these fibers reach the free margin of the valve cusp, where they either ended directly as free nerve endings or lay parallel to the free edge of the cusp, often running between adjacent chordae tendineae. Although the patterns of innervation were similar in both bicuspid and tricuspid valves, the innervation density of the bicuspid valve was greater than that of the tricuspid valve for each species examined.A distinguishing feature of guinea pig and opossum tricuspid valves was that their chordae tendineae were relatively more prominent and more densely innervated than the bicuspid chordae tendineae. Free nerve endings with no light microscopic evidence of specialization were present throughout the bicuspid and tricuspid valves of all species studied. Some nerve endings in the opossum showed evidence of specialization, with brush-like arborizations leading to presumed free terminals seen chiefly in the distal zone of the valve cusps. Although some general tendencies were apparent, we have demonstrated that interspecies heterogeneity exists in the terminal networks of the atrioventricular valves of mouse, rat, guinea pig, and opposum.In spite of the questions raised regarding the significance of valve innervation in light of the success of valve prostheses, there is relatively high morbidity and mortality associated with heart valve replacement, partly due to deterioration in ventricular function. We and other investigators have reported that valvar nerves extend to the chordae and papillary muscles, varying with valve and species.This anatomical information about normal valves helps to lay the foundation for future studies of the role of valve innervation in the regulation of cardiac function and dysfunction. Such knowledge should be applicable for the control and management of myocardial infarction, valve disease, valve replacement, valvuloplasty, cardiac transplantation, administration of drugs, etc.
    Additional Material: 10 Ill.
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  • 10
    ISSN: 0044-8249
    Keywords: Anhydride ; Asymmetrische Synthesen ; Halbester ; TADDOL ; Titanverbindungen ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
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