bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cortical spreading depression and gene regulation: Relevance to migraine
Authors: Choudhuri Rajani , Cui MD Lisa , Yong Chi , Bowyer Susan , Klein Robert M. , Welch MD K. M. A. , Berman Nancy E. J. 
Published: August 2002

AbstractCortical spreading depression (CSD) may be the underlying mechanism of migraine aura. The role of CSD in initiating a migraine headache remains to be determined, but it might involve specific changes in gene expression in the brain. To examine these changes, four episodes of CSD at 5‐minute intervals were induced in the mouse brain by application of 300mM KCl, and gene expression was examined 2 hours later using cDNA array and reverse transcriptase–polymerase chain reaction. Controls consisted of groups that received anesthesia only, attachment of recording electrodes only, and application of 0.9% NaCl. Of the over 1,180 genes examined in our experiments, those consistently regulated by CSD included vasoactive peptides; the vasodilator atrial natriuretic peptide was induced by CSD, while the vasoconstrictor neuropeptide Y was downregulated. Other genes specifically regulated by CSD were involved in oxidative stress responses (major prion protein, glutathione‐S‐transferase‐5, and apolipoprotein E). L‐type calcium channel mRNA was upregulated. In summary, CSD regulates genes that are intrinsic to its propagation, that identify accompanying vascular responses as a potential source of pain, and that protect against its potential pathological consequences. We believe these observations have strong relevance to the mechanisms of migraine and its outcomes.
Induction of proinflammatory molecules in mice with amyotrophic lateral sclerosis: No requirement for proapoptotic interleukin‐1β in neurodegeneration
Authors: Nguyen Minh Dang , Julien Jean‐Pierre , Rivest Serge 
Published: August 2002

AbstractRecent studies have demonstrated the activation of caspase‐1 and caspase‐3 in mice expressing mutant superoxide dismutase 1 (SOD1), models of amyotrophic lateral sclerosis. Caspase‐1 converts the prointerleukin‐1β into a potent proinflammatory molecule involved in the innate immune response and in neurodegenerative diseases. We report on the chronic expression of interleukin‐1β mRNA in the spinal cord of SOD1G37R mice, together with robust mRNA expression for the nuclear factor‐κB (NF‐κB) inhibitor IκBα, for other proinflammatory cytokines and chemokines (interleukin‐6, tumor necrosis factor‐α, monocyte chemoattractant protein‐1) and for the toll‐like receptor TLR2 involved in innate immunity. To further assess the interleukin‐1β contribution to neurodegeneration, we generated mice expressing SOD1G37R in a context of interleukin‐1β gene knockout. Surprisingly, the absence of interleukin‐1β had no effect on the life span of SOD1G37R mice, nor on the extent of motor axon degeneration at age 7 and 10 months. Whereas neither compensatory induction of the interleukin‐1α mRNA nor increases in mRNA levels for IκBα, tumor necrosis factor‐α and macrophage chemoattractant protein‐1 occurred as a result of interleukin‐1β gene disruption, enhanced levels of TLR2 mRNA were detected in SOD1G37R mice lacking interleukin‐1β. We conclude that interleukin‐1β does not directly contribute to motor neuron degeneration in SOD1G37R mice, but it may act as a modulator of the innate immune response.
A newly established cell culture from hybrid catfish (Clarias gariepinus × Clarias macrocephalus) for screening toxicity of triphenyltin hydroxide
Authors: Visoottiviseth Pornsawan , Chanwanna Nantawan 
Published: August 2002

AbstractThree types of primary cell culture can be established from organs of hybrid catfish (Clarias gariepinus × Clarias macrocephalus) namely, caudal trunk, gill and liver. Cell cultures from caudal trunk and gill are composed of mixed cells of fibroblasts and epitheloids, whenever cell cultures from the liver are composed of fibroblastic cells only. All cultures grow well in either Eagle's minimum essential medium (MEM) supplemented with 15–20% fetal calf serum (FCS) or Leibovitz's L‐15 medium supplemented with 5–20% FCS. The optimum growth temperature is 27 °C in an atmosphere either with or without 5% carbon dioxide. The diploid chromosome number as determined from the 19th passage of the caudal trunk cell culture is 56. The cell cultures can be stored at 4 °C for at least 2 months. Experiments were then performed to investigate the possibility of using the established catfish cell culture for screening toxicity of organotin pesticides (triphenyltin hydroxide, TPTH). The results show that the culture is highly suitable for the purpose. The effect of TPTH on cell culture is recognized at a concentration of 3 μm l−1 when cell detachment is used as the test criterion. Established cell culture from hybrid catfish has a great potential as a powerful tool in tropical aquatic toxicology as a method of screening chemicals prior to in vivo testing.
Hydrophilic drug release from bioerodible polyanhydride microspheres
Authors: Vasheghani‐Farahani Ebrahim , Khorram Mohammad 
Published: August 2002

AbstractThe present investigation was carried out to develop bioerodible drug delivery systems. Copolymers of fumaric anhydride and isophthalic anhydride were synthesized by melt polycondensation. To synthesize a copolymer with known composition, soluble in common organic solvents, a prepolymer of each monomer was first prepared. Copolymers were synthesized by mixing two prepolymers followed by melt polycondensation of the resulting mixture with a specific ratio of each prepolymer. Microspheres loaded with theophylline and diltiazem hydrochloride (DHC) were obtained using the solvent removal method in an oil‐in ‐oil (O/O) emulsion system. The size of the drug loaded microspheres was less than 75 μm, which is suitable for subcutaneous or intramuscular injection. DHC was incorporated in a polymeric carrier better than theophylline because of its solubility in chloroform and dichloromethane. In vitro release of two drugs in the phosphate buffer solution indicated that the release profile of DHC was closer to a zero‐order kinetic profile compared with theophylline. Finally, drug release data was compared with three semiempirical models. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1457–1464, 2002
Novel polymer–ceramic nanocomposite based on high dielectric constant epoxy formula for embedded capacitor application
Authors: Rao Yang , Ogitani S. , Kohl Paul , Wong C. P. 
Published: August 2002

AbstractEmbedded capacitor technology can increase silicon packing efficiency, improve electrical performance, and reduce assembly cost compared with traditional discrete capacitor technology. Developing a suitable material that satisfies electrical, reliability, and processing requirements is one of the major challenges of incorporating capacitors into a printed wiring board (PWB). Polymer–ceramic composites have been of great interest as embedded capacitor material because they combine the processability of polymers with the high dielectric constant of ceramics. A novel nanostructure polymer–ceramic composite with a very high dielectric constant (εr ∼110, a new record for the highest reported εr value of a nanocomposite) was developed in this work. A high dielectric constant is obtained by increasing the dielectric constant of the epoxy matrix (εr >6) and using the combination of lead magnesium niobate–lead titanate (PMN–PT)/BaTiO3 as the ceramic filler. This nanocomposite has a low curing temperature (<200°C); thus, it is multichip‐module laminate (MCM‐L) process‐compatible. An embedded capacitor prototype with a capacitance density of 50 nF/cm2 was manufactured using this nanocomposite and spin‐coating technology. The effect of the composite microstructure on the effective dielectric constant was studied. This novel nanocomposite can be used for integral capacitors in PWBs. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1084–1090, 2002
Diffusion of electrolytes in hydrolyzable glassy polymers: Acetic acid in poly(vinyl acetate), poly(vinyl alcohol), and polyesters
Authors: Polishchuk A. Ya. , Valente A. J. M. , Camino G. , Luda M. P. , Madyuskin N. N. , Lobo V. M. M. , Zaikov G. E. , Revellino M. 
Published: August 2002

AbstractEngineering materials containing poly(vinyl acetate) (PVAc) as the key component undergo hydrolytic degradation, which must be minimized or, at least, controlled. To characterize PVAc hydrolysis quantitatively, the diffusion of acetic acid (HAc) in PVAc, poly(vinyl alcohol) (PVA), unsaturated polyester (UPE), and a UPE/PVAc blend was studied in detail. The permeability cell earlier developed by the authors was modified here to reduce experimental error. As the diffusion and solubility coefficients of water and HAc in the above materials were measured at different temperatures, a mathematical model was developed, which takes proper account of the combined water and HAc diffusion in PVAc undergoing partial hydrolysis. The model was further validated by the experimental data obtained at 70°C for UPE/PVAc film, simulating a matrix of sheet‐molding compounds composite materials. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1157–1166, 2002
Preparation, characterization, and behavior of cellulose–titanium(IV) oxide modified with organosilicone
Authors: Meng Ling‐Zhi , Du Chuan‐Qing , Chen Yuan‐Yin , He Yong‐Bing 
Published: August 2002

AbstractCellulose–titanium(IV) oxide modified with organosilicone (CTSN) was prepared by a reaction of cellulose powder with titanic chloride, followed by a reaction with 4‐aza‐6‐aminohexyl triethoxysilane, and was characterized by infrared spectroscopy, scanning electron microscopy (SEM), and thermogravimetric analysis. An SEM image of titanium(IV) oxide‐coated cellulose and a Ti mapping image showed that titanium oxide was well dispersed on the cellulose surface. Titanium and silicon mapping images of CTSN, obtained with SEM, indicated that both oxides were uniformly dispersed on the cellulose surface. The atomic ratio of Ti to Si was obtained with X‐ray energy spectral composition analysis. The adsorption behavior of CTSN toward Hg(II), Cu(II), Pb(II), Fe(III), and Cr(III) ions in aqueous solutions was determined. The adsorption behavior of CTSN toward human serum protein was preliminarily examined. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 61–66, 2002; DOI 10.1002/app.10188
In‐line and in situ monitoring of semi‐batch emulsion copolymerizations using near‐infrared spectroscopy
Authors: Vieira Raphael A. M. , Sayer Claudia , Lima Enrique L. , Pinto José Carlos 
Published: August 2002

AbstractThis article shows that near‐infrared spectroscopy (NIRS) can be used efficiently for the simultaneous in‐line and in situ monitoring of monomer (methyl methacrylate, MMA, and butyl acrylate, BuA) and polymer concentrations in the reaction medium during seeded semibatch emulsion copolymerizations. A series of actual reaction experiments was planned to allow the proper obtainment and selection of calibrating samples. Partial least squares (PLS) was used to build three independent calibration equations in the range of 1100–1900 nm, which were used to successfully monitor some disturbed reactions in‐line. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2670–2682, 2002
Thermal behavior of polyaniline films and polyaniline–polystyrene blends
Authors: Jousseaume V. , Morsli M. , Bonnet A. 
Published: August 2002

AbstractIn this article, a study of the thermal behavior of polyaniline films and polyaniline–polystyrene blends is presented. Transport measurements (electrical conductivity and thermoelectric power) at high temperature and thermogravimetric analysis show that an irreversible degradation is observed near 450 K for films doped with DiOHP and near 500 K for films doped with CSA. In both cases, the thermoelectric power is the most sensitive parameter to electrical degradation during the heating of conducting films. Electrical conductivity measurements during heating–cooling cycles show a diminution of the room temperature conductivity after evaporation of the solvent (water, m‐cresol). A model of cluster with a variable diameter allows interpreting this phenomenon by assuming the existence of a sensitive frontier to the solvent at the periphery of conducting clusters. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1848–1855, 2002; DOI 10.1002/app.10468
Preparation and properties of aromatic polyimides based on 4,4′‐(2,2,2‐trifluoro‐1‐phenylethylidene)diphthalic anhydride
Authors: Lee Dong‐Ho , Koo Seung‐Young , Lee Hyung‐Seok , Kim Woo Sik , Min Kyung Eun , Park Lee Soon , Seo Kwan Ho , Kang Inn Kyu , Choi Heung‐Jin 
Published: August 2002

AbstractAromatic polyimides were synthesized from aromatic carboxylic acid dianhydrides, 2,2‐bis(3,4‐dicarboxyphenyl)hexafluoropropane dianhydride (6FDA), 4,4′‐(2,2,2‐trifluoro‐1‐phenylethylidene)diphthalic anhydride (3FDA), and pyromellitic dianhydride (PMDA), with four typical aromatic diamines. These included polyimide (PI) from 2,2‐bis(4‐aminophenyl)hexafluoropropane (4BDAP) by two‐step procedures; amidation to polyamic acid (PAA), followed by thermal imidization of PAA. The chemical and physical properties of the newly prepared polyimides were compared in terms of their chemical structures, inherent viscosity, thermal property, transmission, dielectric constant, UV cutoff, water absorption, and refractive index. PIs 3FDA/4BDAP and 6FDA/4BDAP were soluble in common organic solvents, whereas others were not. In particular, it was found that the solubility was dependent on the temperature of imidization. The chemical and physical properties of the newly prepared polyimides derived from 3FDA were similar to the polyimides derived from 6FDA. The solubility of polyimide containing an ether functional group in the dianhydride moiety was better than that of the ether functional group in the diamine moiety. The polymers with ether linkage in dianhydride moiety exhibited lower glass transition temperature than their functionality‐reversed analogous polymers with ether linkage in diamine moiety. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 38–44, 2002
Copolymerization of propene with phenylnorbornene using ansa‐bridged metallocene catalysts
Authors: Aitola Erkki , Repo Timo , Bergström Christer , Leskelä Markku 
Published: August 2002

AbstractPropene was copolymerized with phenylnorbornene using methylaluminumoxane (MAO)‐activated metallocene dichlorides exhibiting different symmetry: C2‐Symmetric rac‐ethylenebis(1‐ indenyl)zirconium dichloride (1), rac‐ dimethylsilylbis(1‐indenyl)zirconium dichloride (2), rac‐ethylenebis(1‐indenyl)hafnium dichloride (6), Cs‐symmetric isopropylidene(cyclopentadienyl‐9‐fluorenyl)zirconium dichloride (3), meso‐ethylenebis(1‐indenyl)zirconium dichloride (4), and C1‐symmetric ethylene(1‐ fluorenyl‐1‐phenyl‐2‐indenyl)zirconium dichloride (5) were chosen to evaluate the influence of the symmetry in copolymerization reactions. Experiments were done as batch polymerizations to produce homogeneous copolymers. By this setup, blend formation was avoided. The copolymers were characterized by NMR, GPC, and DSC. Catalysts 1 and 2 were the most active to copolymerize random, amorphous, copolymers with good activity. Cs‐symmetric, 3, showed decreased activity compared with 1 and 2 and produced a bimodal copolymer. Catalyst 4 showed even lower activity than that of 3. The activity of the hafnium complex 6, which produced a semicrystalline polymer with a high molecular weight (116,000 g/mol) was 320 kg/mol. Catalyst 1 produced the highest comonomer content (42%) in the copolymers measured by NMR. The least active catalyst was 5 (phenyl croup in the bridge), producing only 290 kg copolymer per mole of catalyst. All polymers had elevated glass transition temperatures compared to polypropylene. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2743–2752, 2002
Thermodynamics of surface self‐developing structure formation on polyamide films under ultraviolet irradiation
Authors: Rebouillat Serge , Lavielle Lisette , Wilmet Sophie 
Published: August 2002

AbstractPolyamide terpolymer films can be obtained by the evaporation of a solvent–terpolymer–photoinitiator mixture on a glass plate. Through ultraviolet (UV) irradiation, self‐developing properties are observed. The nuclear magnetic resonance (NMR) study of the photochemical reaction involved in such a process permits us to propose a mechanism with a diffusion of solvent in the irradiated areas. The thermodynamics of irreversible process have been applied to the analysis of such a system behavior, and an analysis of the stability of the system resulting from its residual solvent content has been made. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 645–653, 2002
Syntheses of acrylate core/shell imbiber beads by seeded suspension copolymerization and one‐stage copolymerization for solvent absorption–desorption
Authors: Kiatkamjornwong Suda , Akkarakittimongkol Pranut , Omi Shinzo 
Published: August 2002

AbstractSeeded suspension copolymerization or a one‐stage copolymerization was used to synthesize acrylate core/shell imbiber beads. A two‐stage polymerization technique was used for seeded suspension polymerization. The seed particles for poly(methyl acrylate) or poly(2‐ethylhexyl acrylate) were synthesized first in a mixed solvent of toluene/isooctane containing the ethylene glycol dimethacrylate (EGDMA) crosslinking agent. These beads were swollen in styrene‐EGDMA‐BPO (benzoyl peroxide) and then polymerized in the aqueous phase to produce the polystyrene (PS) shell. The one‐stage copolymerization was carried out in toluene/isooctane containing methyl methacrylate (MMA), styrene (St), EGDMA, and BPO at 75°C for 10 h to give a core/shell copolymer of St‐MMA morphology. The appearance of core/shell imbiber beads prepared from these two techniques varied from monomer to monomer. This article describes the preparation, characterization, and application of the core/shell beads for organic solvent absorption/desorption. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 670–682, 2002
Phase‐separated polymer blends: Complementary studies between scanning electron microscopy, epifluorescence microscopy, and fluorescence microspectroscopy
Authors: Granados E. G. , González‐Benito J. , Baselga J. , Dibbern‐Brunelli D. , Atvars T. D. Z. , Esteban I. , Piérola I. F. 
Published: August 2002

AbstractIn this work a morphological description of poly(vinyl alcohol) (PVA)/poly(vinyl acetate) (PVAc) incompatible blends was carried out combining scanning electron microscopy, epifluorescence microscopy, and fluorescence microspectroscopy, and using anthracene and fluorescein probes dissolved in the polymer blends. Because the blends were prepared by casting from a water/ethanol solution over a polyethylene surface, two topologically different faces were formed and analysed: blend/air and blend/support faces. Droplets in matrix morphologies were observed for any composition here studied and sample annealing resulted in the coalescence of domains. Fluorescence micro‐spectroscopy of several parts of the material revealed that the dye distribution over the domain‐matrix interface is different of the internal or external parts of each domain and it is indicative of the interpenetration of both polymers at the interface region. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 949–955, 2001
Nitro derivatives of PEEK‐WC
Authors: Trotta Francesco , Drioli Enrico , Gordano Amalia 
Published: August 2002

AbstractNitrated poly(oxa‐p‐phenylene‐3,3‐phthalido‐p‐phenylene‐oxa‐p‐phenylene‐ oxy‐phenylene) (PEEK‐WC) with various average degrees of substitution was obtained by reaction with several nitrating agents. By working under controlled reaction conditions, little degradation of the parent polymer is observed. The nitro derivatives of PEEK‐WC show a high thermal stability, and are able to form membranes by means of phase inversion technique. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1037–1045, 2001
Preparation of water‐swollen hydrogel membranes for gas separation
Authors: Park You‐In , Lee Kew‐Ho 
Published: August 2002

AbstractWater‐swollen hydrogel (WSH) membranes for gas separation were prepared by the dip‐coating of asymmetric porous polyetherimide (PEI) membrane supports with poly(vinyl alcohol) (PVA)–glutaraldehyde (GA), followed by the crosslinking of the active layer by a solution method. Crosslinked PVA/GA film of different blend compositions (PVA/GA = 1/0.04, 0.06, 0.08, 0.10, 0.12 mol %) were characterized by differential scanning calorimetry (DSC) and their water‐swelling ratio. The swelling behavior of PVA/GA films of different blend compositions was dependent on the crosslinking density and chemical functional groups created by the reaction between PVA and GA, such as the acetal group, ether linkage, and unreacted pendent aldehydes in PVA. The permeation performances of the membranes swollen by the water vapor contained in a feed gas were investigated. The behavior of gas permeation through a WSH membrane was parallel to the swelling behavior of the PVA/GA film in water. The permeation rate of carbon dioxide through the WSH membranes was 105 (cm3 cm−2 s−1 cmHg) and a CO2/N2 separation factor was about 80 at room temperature. The effect of the additive (potassium bicarbonate, KHCO3) and catalyst (sodium arsenite, NaASO2) on the permeation of gases through these WSH membranes was also studied. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1785–1791, 2001
Effect of linear comonomers on the rate of crystallization of copolyesters
Authors: Connor Daniel M. , Allen Scott D. , Collard David M. , Liotta Charles L. , Schiraldi David A. 
Published: August 2002

AbstractSmall amounts of dimethyl‐4,4′‐biphenyldicarboxylate, 2,7‐dimethyl‐4,5,9,10‐tetrahydropyrenedicarboxylate, and dimethyl‐2,7‐pyrenedicarboxylate have been copolymerized into poly(ethylene) terephthalate (PET). The thermal transitions of the copolymers have been characterized, and the crystallization rates have been measured isothermally. Avrami analysis indicates that all the copolymers crystallized at a slower rate than that of the PET homopolymer. Addition of perylene to the copolymers containing pyrene enhanced the rate of crystallization, which could be the consequence of stacked arene assemblies serving as templates for crystal formation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2696–2704, 2001
Styrene‐ethylene/butylene‐styrene blends for improved constrained‐layer damping
Authors: Öborn Jonas , Bertilsson Hans , Rigdahl Mikael 
Published: August 2002

AbstractThe influence on the adhesion to some metal surfaces and the damping properties of various modified styrene‐ethylene/butylene‐styrene (SEBS) materials was evaluated. Modification of the different phases of the SEBS with resins was shown to have a large effect on the damping properties of the polymers, which were evaluated by dynamic mechanical analysis (DMA). A small amount of maleic anhydride grafted onto the EB block was found to lead to a significant improvement in the adhesion of the polymer to some metal surfaces without affecting the damping properties of the polymers. The results of the DMA tests on the polymers were used to calculate the composite loss factor (CLF) for a steel laminate, which consisted of two steel plates with a polymeric layer in between, according to the theory proposed by Ross, Ungar, and Kerwin. The calculated results were compared with the measured CLFs determined in vibrating beam tests (VBTs). The agreement between the calculated and measured values was quite fair, provided that the DMA values used for the calculations were recalculated to the actual higher frequencies used in the VBTs, using the time–temperature superposition principle. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2865–2876, 2001