bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nuclear factor‐κB as a molecular target for migraine therapy
Authors: Reuter Uwe , Chiarugi Alberto , Bolay Hayrunnisa , Moskowitz Michael A. 
Published: August 2002

AbstractNitric oxide (NO) generated from inducible NO synthase (iNOS) participates in immune and inflammatory responses in many tissues. The NO donor glyceryl trinitrate (GTN) provokes delayed migraine attacks when infused into migraineurs and also causes iNOS expression and delayed inflammation within rodent dura mater. Sodium nitroprusside, an NO donor as well, also increases iNOS expression. Because inflammation and iNOS are potential therapeutic targets, we examined transcriptional regulation of iNOS following GTN infusion and the consequences of its inhibition within dura mater. We show that intravenous GTN increases NO production within macrophages. L‐N(6)‐(1‐iminoethyl)lysine, a selective iNOS inhibitor, attenuates the NO signal, emphasizing the importance of enzymatic activity to delayed NO production. iNOS expression is preceded by significant nuclear factor kappa B (NF‐κB) activity, as reflected by a reduction in the inhibitory protein‐κ‐Bα (IκBα) and activation of NF‐κB after GTN infusion. IκBα degradation, NF‐κB activation, and iNOS expression were attenuated by parthenolide (3mg/kg), the active constituent of feverfew, an anti‐inflammatory drug used for migraine treatment. These findings suggest that GTN promotes NF‐κB activity and inflammation with a time course consistent with migraine attacks in susceptible individuals. We conclude, based on results with this animal model, that blockade of NF‐κB activity provides a novel transcriptional target for the development of anti‐migraine drugs.
Microarray analysis of hippocampal gene expression in global cerebral ischemia
Authors: Jin Kunlin , Mao Xiao Ou , Eshoo Mark W. , Nagayama Tetsuya , Minami Manabu , Simon Roger P. , Greenberg David A. 
Published: August 2002

AbstractThe brain's response to ischemia, which helps determine clinical outcome after stroke, is regulated partly by competing genetic programs that respectively promote cell survival and delayed cell death. Many genes involved in this response have been identified individually or systematically, providing insights into the molecular basis of ischemic injury and potential targets for therapy. The development of microarray systems for gene expression profiling permits screening of large numbers of genes for possible involvement in biological or pathological processes. Therefore, we used an oligodeoxynucleotide‐based microarray consisting of 374 human genes, most implicated previously in apoptosis or related events, to detect alterations in gene expression in the hippocampus of rats subjected to 15 minutes of global cerebral ischemia followed by up to 72 hours of reperfusion. We found 1.7‐fold or greater increases in the expression of 57 genes and 1.7‐fold or greater decreases in the expression of 34 genes at 4, 24, or 72 hours after ischemia. The number of induced genes increased from 4 to 72 hours, whereas the number of repressed genes decreased. The induced genes included genes involved in protein synthesis, genes mutated in hereditary human diseases, proapoptotic genes, antiapoptotic genes, injury‐response genes, receptors, ion channels, and enzymes. We detected transcriptional induction of several genes implicated previously in cerebral ischemia, including ALG2, APP, CASP3, CLU, ERCC3, GADD34, GADD153, IGFBP2, TIAR, VEGF, and VIM, as well as other genes not so implicated. We also found coinduction of several groups of related genes that might represent functional modules within the ischemic neuronal transcriptome, including VEGF and its receptor, NRP1; the IGF1 receptor and the IGF1‐binding protein IGFBP2; Rb, the Rb‐binding protein E2F1, and the E2F‐related transcription factor, TFDP1; the CACNB3 and CACNB4 β‐subunits of the voltage‐gated calcium channel; and caspase‐3 and its substrates, ACINUS, FEM1, and GSN. To test the hypothesis that genes identified through this approach might have roles in the pathophysiology of cerebral ischemia, we measured expression of the products of two induced genes not heretofore implicated in cerebral ischemia—GRB2, an adapter protein involved in growth‐factor signaling pathways, and SMN1, which participates in RNA processing and is deleted in most cases of spinal muscular atrophy. Western analysis showed enhanced expression of both proteins in hippocampus at 24 to 72 hours after ischemia, and SMN1 was localized by immunohistochemistry to hippocampal neurons. These results suggest that microarray analysis of gene expression may be useful for elucidating novel molecular mediators of cell death and survival in the ischemic brain.
Metabolism of dimethylarsinic acid in rats: production of unidentified metabolites in vivo
Authors: Yoshida Kaoru , Kuroda Koichi , Inoue Yoshinori , Chen Hua , Date Yukiko , Wanibuchi Hideki , Fukushima Shoji , Endo Ginji 
Published: August 2002

AbstractOur previous study revealed that two unidentified metabolites, M‐1 and M‐2, were excreted in urine after long‐term oral administration of dimethylarsinic acid (DMA), the main metabolite of inorganic arsenic. In the present study, we attempted to clarify the mechanism of production of these unknown metabolites. Male F344/DuCrj rats were administered a single dose of DMA (50 mg kg−1) orally or intraperitoneally with or without pretreatment with L‐buthionine‐SR‐sulfoximine (BSO), which inhibits glutathione (GSH) synthesis. Urine was collected by forced urination at various time points after administration of DMA. Arsenic metabolites in urine were analyzed by ion chromatography with inductively coupled plasma mass spectrometry (IC–ICP‐MS). The unidentified metabolites M‐1 and M‐2 were excreted later than elimination of DMA and trimethylarsine oxide (TMAO). GSH depletion decreased in TMAO elimination, suggesting that GSH plays important roles in the methylation of DMA to TMAO in rats. There was no difference in the amount of production of either M‐1 or M‐2 between BSO‐pretreated rats and controls, suggesting that M‐1 and M‐2 cannot be formed during methylation in the liver. The amounts of elimination of M‐1 and M‐2 were less after intraperitoneal administration than after oral administration.Male F344/DuCrj rats were given 100 mg As l−1 DMA via drinking water for 20 weeks. Urine and feces were collected forcibly and were analyzed by IC–ICP‐MS. A new unidentified metabolite, M‐3, was detected only in feces as a metabolite of DMA after 20 weeks exposure to DMA, although M‐1 and M‐2 were found in both urine and feces. The unidentified metabolites M‐1, M‐2, and M‐3 were excreted mainly as fecal metabolites along with unmetabolized DMA. This finding also suggests that M‐1, M‐2, and M‐3 might be produced in the intestinal tract. Copyright © 2001 John Wiley & Sons, Ltd.
Toxic effect of triphenyltin chloride on the alga Spirulina subsalsa
Authors: Huang Guolan , Song Zhihui , Liu Guangliang , Zhang Weihua 
Published: August 2002

AbstractA previous study on the deleterious effect of triphenyltin chloride (TPTCl) on the alga Spirulina subsalsa reported on four physiological and biochemical indices (or parameters): growth rate, chlorophyll content, phycocyanin content and nitrate reductase activity. In the present study, further research was performed to confirm the findings reported in the previous paper, using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The SEM images show significant changes in the screw‐pitch of S. subsalsa, suggesting that TPTCl may damage the inheritance characteristics of S. subsalsa. The TEM images illustrate that the external pectin theca, limiting membrane and inter photosynthetically active lamella in the S. subsalsa cell are those targets that can be easily damaged. Reversible and irreversible cell damage (cell necrosis) are also observed. Copyright © 2002 John Wiley & Sons, Ltd.
Synthesis and characterization of novel poly(amide imide)s based on bis(p‐amidobenzoic acid)‐n‐trimellitylimido‐L‐leucine
Authors: Mallakpour Shadpour E. , Hajipour Abdol‐Reza , Vahabi Ramin 
Published: August 2002

AbstractN‐Trimellitylimido‐L‐leucine was reacted with thionyl chloride, and N‐trimellitylimido‐L‐leucine diacid chloride was obtained in a quantitative yield. The reaction of this diacid chloride with p‐aminobenzoic acid was performed in dry tetrahydrofuran, and bis(p‐amidobenzoic acid)‐N‐trimellitylimido‐L‐leucine (5) was obtained as a novel optically active aromatic imide–amide diacid monomer in a high yield. The direct polycondensation reaction of the monomer imide–amide diacid 5 with 4,4′‐diaminodiphenylsulfone, 4,4′‐diaminodiphenylether, 1,4‐phenylenediamine, 1,3‐phenylenediamine, 2,4‐diaminotoluene, and benzidine (4,4′‐diaminobiphenyl) was carried out in a medium consisting of triphenyl phosphite, N‐methyl‐2‐pyrolidone, pyridine, and calcium chloride. The resulting novel poly(amide imide)s (PAIs), with inherent viscosities of 0.22–0.52 dL g−1, were obtained in high yields, were optically active, and had moderate thermal stability. All of the compounds were fully characterized with IR spectroscopy, elemental analyses, and specific rotation. Some structural characterization and physical properties of these new optically active PAIs are reported. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 35–43, 2002; DOI 10.1002/app.10181
Ionically conductive polymer gel electrolytes consisting of crosslinked methacrylonitrile and organic electrolyte
Authors: Kubota Naoji , Fujii Shigetada , Tatsumoto Nobuhide , Sano Takayuki 
Published: August 2002

AbstractTo develop a highly ion‐conductive polymer electrolyte, we copolymerized methacrylonitrile (MAN) with ethylene glycol dimethacrylate (EGDMA) in propylene carbonate that contained tetraethylammonium tetrafluoroborate (TEATFB), changing the TEATFB concentration and the MAN/EGDMA molar ratio. We characterized the obtained polymer gel electrolytes with complex impedance analysis and cyclic voltammetry, intending to apply them to electric double‐layer capacitors. The ionic conductivities of the polymer gel electrolytes were dependent on the TEATFB concentration, the temperature, and particularly the crosslinking degree. The polymer gel electrolytes in this system exhibited high room‐temperature conductivities (>10−3 S/cm). Furthermore, these polymer electrolytes showed good electrochemical stability windows ranging from −4.0 to +4.0 V versus Ag. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2655–2659, 2002
Preparation of thermal‐responsive poly(propylene) membranes grafted with n‐isopropylacrylamide by plasma‐induced polymerization and their water permeation
Authors: Kim So Yeon , Kanamori Toshiyuki , Shinbo Toshio 
Published: August 2002

AbstractPoly(propylene) (PP) membrane grafted with poly(N‐isopropylacrylamide) (PNIPAAm), which is known to have a lower critical solution temperature (LCST) at around 32°C, was prepared by the plasma‐induced graft polymerization technique. Graft polymerization of PNIPAAm onto a PP membrane was confirmed by microscopic attenuated total reflection/Fourier transform IR spectroscopy. The grafting yield of PNIPAAm increased with the concentration of N‐isopropylacrylamide monomer and the reaction time of graft polymerization. The average pore size of the PP membrane also affected the grafting yield. From the field emission scanning electron microscopy (FE‐SEM) measurement, we observed a morphological change in the PP‐g‐PNIPAAm membrane under wet conditions at 25°C below LCST. The permeability of water through the PP‐g‐PNIPAAm membrane was controlled by temperature. The PP‐g‐PNIPAAm membrane (PN05 and PN10) exhibited higher water permeability (Lp) than the original PP substrate membrane below LCST. As the temperature increased to above LCST, Lp gradually decreased. In addition, the graft yield of PNIPAAm and the average pore size of the PP substrate influenced water permeability. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1168–1177, 2002; DOI 10.1002/app.10410
Moisture‐sorption characteristics of starch/low‐density polyethylene films
Authors: Raj Baldev , Raj A. Eugene , Kumar K. R. , Siddarramaiah  
Published: August 2002

AbstractMoisture‐sorption characteristics of starch/low‐density polyethylene (LDPE) blends were carried out at 27°C for water activity (aw) from 0.1 to 0.9. The sorption data were used to fit six different sorption isotherm models proposed in the literature. The model constants were determined by linear fitting of the sorption equations. The ranges of applicability of water activity for the isotherm models reported in the article lies between 0.1 and 0.4 (monomolecular layer) for the BET model and between 0.3 and 0.9 (multimolecular and capillary condensation layers) for other models. The value of the coefficient of determination (R2= 0.97 ± 0.02) confirms the linear fitting of the equations studied. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1193–1202, 2002; DOI 10.1002/app.10417
Polysiloxane modified epoxy networks. IV. Catalytic effect on fracture behaviors of jointed interpenetrating polymer networks
Authors: Wu Shin‐Yu , Lee Shiao‐Lin , Chang Wen‐Lie , Sung Po‐Hou 
Published: August 2002

AbstractJointed interpenetrating polymer networks of epoxy resin and poly(dimethylsiloxane) (PDMS) are synthesized using PDMS‐α,ω ‐diol as the reactive modifier. We attempt to control the reaction rate and the morphology of the rubber domains by using the acid as the catalyst. According to the scanning electron microscopy results, the morphologies of the acid catalyzed specimens do not show strain‐induced crystallization during the fracture mode due to the homogeneity of the molecule structure. The tensile strengths and moduli decrease when the reaction rate is increased. However, the acid contents have no effect on the fracture energy. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2352–2357, 2002
Mechanical properties of poly(lactic acid) and wheat starch blends with methylenediphenyl diisocyanate
Authors: Wang Hua , Sun Xiuzhi , Seib Paul 
Published: August 2002

AbstractPoly(lactic acid) (PLA) and wheat starch are biodegradable polymers derived from renewable sources. A previous study showed that thermally blending starch and PLA in the presence of methylenediphenyl diisocyanate (MDI) enhanced the mechanical properties of the blends. In this work, blends of PLA with various levels of wheat starch and MDI were hot mixed at 180°C then hot‐pressure molded at 175°C to form test specimens. The blends were characterized for mechanical properties, fracture microstructure, and water absorption. Pure PLA had a tensile strength of 62.7 MPa and elongation of 6.5%. The blend with 45% wheat starch and 0.5 wt % MDI gave the highest tensile strength of about 68 MPa with about 5.1% elongation. The blend with 20% starch and 0.5 wt % MDI had the lowest tensile strength of about 58 MPa with about 5.6% elongation. Dynamic mechanical analysis showed that storage modulus increased and tan δ decreased as starch level increased, but almost leveled off when starch level reached 45% or higher. Water absorption of the blends increased significantly with starch content. Yet the blend, if water proofed on its surface, has potential for short‐term disposable applications. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1257–1262, 2002; DOI 10.1002/app.10457
Structure and damping properties of polydimethylsiloxane and polymethacrylate sequential interpenetrating polymer networks
Authors: Huang Guang‐Su , Li Qiang , Jiang Lu‐Xia 
Published: August 2002

AbstractBy using the technology of the sequential interpenetrating polymer network, a series of novel damping materials based on a polydimethylsiloxane (PDMS)/polyacrylate (PAC) matrix with polymethacrylate (PMAC) were synthesized. They have a controllable broad transition peak spanning the temperature range of 150–220°C and the medial value of loss factor with maximum of 0.35–0.60. Dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and atomic force microscopy (AFM) were applied to analyze and characterize the transition behavior and the microphase structure of the materials. It was found that the size and height of a transition peak at both the low‐ and the high‐temperature zones change as a function not only of the concentration of PMAC and PDMS but also of the kind of PMAC; simultaneously, the low‐ temperature behavior was also governed by the crystallization of PDMS. The content of the crosslinking agent exerts a significant influence on the configuration of the curves of the transition peaks. AFM shows a characteristic phase morphology of double‐phase continuity containing a transition layer and domain less than 1 μm, indicating that the interwoven multilayer networks are the key to incorporation of the immiscible components and form a broad damping functional region. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 545–551, 2002
Pyrolysis of polymethylsilsesquioxane
Authors: Ma Jun , Shi Lianghe , Shi Yongyxi , Luo Shanguo , Xu Jian 
Published: August 2002

AbstractChanges of the composition and structure of various samples of polymethylsilsesquioxane (PMSQ), pyrolyzed at different temperatures under flowing nitrogen, were investigated using thermogravimetric analysis, Raman and Fourier transform infrared spectroscopies, X‐ray photoelectron spectroscopy, elemental analysis, scanning electron microscopy, and transmission electron microscopy. The center of the Si2p peak could be used to estimate the extent of the pyrolysis of PMSQ. Two temperature domains correspond to important changes in the chemical composition of PMSQ. The former (Tp < 500°C) is related to the conversion from a regular structure to an irregular structure and the latter (Tp > 500°C) is associated with the organic– ceramic conversion. During the latter pyrolysis, flowing of the molten bulk occurred and then a final solid structure was obtained. The main product of PMSQ, pyrolyzed at 900°C, is silica, as well as some amount of silicon oxycarbide and traces of amorphous carbon. Based on the above analysis and observation, a conversion process from polysilsesquioxane to a ceramic is proposed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1077–1086, 2002
Effects of hygrothermally decomposed polyurethane on the curing and mechanical properties of carbon black‐filled epoxidized natural rubber vulcanizates
Authors: Mohd Ishak Z. A. , Wan P. Y. , Wong P. L. , Ahmad Z. , Ishiaku U. S. , Karger‐Kocsis J. 
Published: August 2002

AbstractHygrothermally decomposed polyurethane (HD‐PUR) was mixed up to 20 phr in epoxidized natural rubber (with 50 mol % epoxidation; ENR50) recipes, and the curing and mechanical behaviors were studied. Mechanical testing of the ENR50/HD‐PUR vulcanizates determined the tensile, tear, compression‐set, hardness, abrasion, hysteresis, and resilience properties. No significant changes were observed in the tensile properties with the incorporation of HD‐PUR. The ENR50 compounds showed an increase in compression set with increasing HD‐PUR content. Rubbers cured by a semi‐efficient vulcanization system gave the best overall performance. A further improvement in curing and mechanical properties was achieved by the carbon black grade N330 being replaced with a more active grade (N375). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2265–2276, 2002
Synthesis and properties of polycarbonate‐poly(methyl methacrylate) graft copolymers by polycondensation of macromonomers
Authors: Okamoto Masaya 
Published: August 2002

AbstractPolycarbonates (PCs) having poly(methyl methacrylate)s (PMMAs) as graft chains were prepared by the polycondensation of PC oligomers bearing chloroformate groups as the end groups with dicarboxyl‐terminated PMMA macromonomers, which were prepared by the radical polymerization of methyl methacrylate in the presence of thiomalic acid as a chain transfer. The resulting PC‐PMMA graft copolymers were transparent in comparison with PC/PMMA blend polymers, and had higher Vickers hardness than blend polymers when both of them had the same PMMA content. According to the results of multiple regression analysis, the improvement of Vickers hardness was conducive to length (46%) and number (37%) of PMMA branches. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2670–2675, 2001
Glass‐transition and melting behavior of poly(ethylene terephthalate)/poly(ethylene 2,6‐naphthalate) blends
Authors: Shi Yu , Jabarin Saleh A. 
Published: August 2002

AbstractThe glass‐transition temperatures and melting behaviors of poly(ethylene terephthalate)/poly(ethylene 2,6‐naphthalate) (PET/PEN) blends were studied. Two blend systems were used for this work, with PET and PEN of different grades. It was found that Tg increases almost linearly with blend composition. Both the Gibbs–DiMarzio equation and the Fox equation fit experimental data very well, indicating copolymer‐like behavior of the blend systems. Multiple melting peaks were observed for all blend samples as well as for PET and PEN. The equilibrium melting point was obtained using the Hoffman–Weeks method. The melting points of PET and PEN were depressed as a result of the formation of miscible blends and copolymers. The Flory–Huggins theory was used to study the melting‐point depression for the blend system, and the Nishi–Wang equation was used to calculate the interaction parameter (χ12). The calculated χ12 is a small negative number, indicating the formation of thermodynamically stable, miscible blends. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 11–22, 2001
Solubility of additives: Grafting of itaconic acid onto LDPE by reactive extrusion. II. Effect of stabilizers
Authors: Pesetskii S. S. , Jurkowski B. , Krivoguz Y. M. , Olkhov Y. A. 
Published: August 2002

AbstractStatic and dynamic mixers set on the Brabender plastograph were used to investigate the grafting of itaconic acid (IA) onto low‐density polyethylene (LDPE) by the reactive extrusion. The initiators of free‐radical reactions were monoperoxide 2,5‐dimethyl‐2‐hydroxy‐5‐tert‐butylperoxy‐3‐hexyne and diperoxide 2,5‐dimethyl‐2,5‐di(tert‐butyl peroxy)‐hexane. The reaction mix contained stabilizers of phenolic type as follows: 2,6‐ditert‐butyl‐4‐methyl phenol; ester of 3,5‐ditert‐butyl‐4‐hydroxyphenyl‐propanoic acid and pentaerythritol; 4‐alkoxy‐2‐hydroxy‐benzophenone; and 1,4‐dihydroxybenzene. The effect of stabilizers, which follow the radical mechanism on the grafting of IA and on the crosslinking, depends on their solubility in the polymer and the monomer. The stabilizers (e.g., 1,4‐dihydroxybenzene) with increased affinity toward the monomer reduce the grafting yield and inhibit crosslinking. At 0.3–0.5 wt % of the stabilizer insoluble in the monomer, the grafting yield can be increased, while inhibiting the LDPE‐g‐IA crosslinking, irrespective of the peroxide used. Hence, classical stabilizers can initiate grafting reactions at raised concentrations, temperatures, and application of the shearing stresses. They also help to obtain a high‐grafting yield and a reduced crosslinking degree. A stabilizer, having a close affinity toward LDPE, influences the LDPE‐g‐IA structure. The stabilizer content of 0.5 wt % transforms the topological structure of LDPE‐g‐IA into uniblock. Its molecular weight distribution (MWD) may be narrow (−Mn/−Mw < 2) or broad (−Mn/−Mw > 2), depending on the concentration of the initiator used. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3439–3448, 2001