bluuebunny/crossref_metadata_2025_split huggingface dataset:
Possibility for neurogenesis in substantia nigra of parkinsonian brain
Authors: Yoshimi Kenji , Ren Yong‐Ri , Seki Tatsunori , Yamada Masanori , Ooizumi Hideki , Onodera Masafumi , Saito Yuko , Murayama Shigeo , Okano Hideyuki , Mizuno Yoshikuni , Mochizuki Hideki 
Published: May 2005

AbstractRecent studies of enhanced hippocampal neurogenesis by antidepressants suggest enhancement of neurogenesis is a potentially effective therapy in neurodegenerative diseases. In this study, we evaluated nigral neurogenesis in animals and autopsy brains including patients with Parkinson's disease (PD). First, proliferating cells in substantia nigra were labeled with retroviral transduction of green fluorescent protein, which is an efficient method to label neuronal stem cells. Subsequent differentiation of labeled cells was followed; many transduced cells became microglia, but no differentiation into tyrosine hydroxylase–positive neurons was detected at 4 weeks after injection, in both intact rodents and those treated with 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine. Second, polysialic acid (PSA)–like immunoreactivity, indicative of newly differentiated neurons, was detected in the substantia nigra of rodent, primate, and human midbrains. A large number of PSA‐positive cells were detected in the substantia nigra pars reticulata of some patients with PD. In rats and a macaque monkey, the dopamine‐depleted hemispheres showed more PSA staining than the intact side. A small number of tyrosine hydroxylase–positive cells were PSA‐positive. Our results suggest enhanced neural reconstruction in PD, which may be important in the design of new therapies against the progression of PD. Ann Neurol 2005
Functional anatomy of the basal ganglia in X‐linked recessive dystonia‐parkinsonism
Authors: Goto Satoshi , Lee Lillian V. , Munoz Edwin L. , Tooyama Ikuo , Tamiya Gen , Makino Satoshi , Ando Satoshi , Dantes Marita B. , Yamada Kazumichi , Matsumoto Sadayuki , Shimazu Hideki , Kuratsu Jun‐Ichi , Hirano Asao , Kaji Ryuji 
Published: May 2005

AbstractDystonia is a neurological syndrome characterized by sustained muscle contractions that produce repetitive twisting movements or abnormal postures. X‐linked recessive dystonia parkinsonism (XDP; DYT3; Lubag) is an adult‐onset disorder that manifests severe and progressive dystonia with a high frequency of generalization. In search for the anatomical basis for dystonia, we performed postmortem analyses of the functional anatomy of the basal ganglia based on the striatal compartments (ie, the striosomes and the matrix compartment) in XDP. Here, we provide anatomopathological evidence that, in the XDP neostriatum, the matrix compartment is relatively spared in a unique fashion, whereas the striosomes are severely depleted. We also document that there is a differential loss of striatal neuron subclasses in XDP. In view of the three‐pathway basal ganglia model, we postulate that the disproportionate involvement of neostriatal compartments and their efferent projections may underlie the manifestation of dystonia in patients with XDP. This study is the first to our knowledge to show specific basal ganglia pathology that could explain the genesis of dystonia in human heredodegenerative movement disorders, suggesting that dystonia may result from an imbalance in the activity between the striosomal and matrix‐based pathways. Ann Neurol 2005
A PD‐1 polymorphism is associated with disease progression in multiple sclerosis
Authors: Kroner Antje , Mehling Matthias , Hemmer Bernhard , Rieckmann Peter , Toyka Klaus V. , Mäurer Mathias , Wiendl Heinz 
Published: May 2005

AbstractT cells are considered to play a pivotal role in orchestrating the self‐reactive immune responses in multiple sclerosis (MS). Programmed death 1 (PD‐1) is a member of the B7/CD28 superfamily of costimulatory molecules exerting inhibitory functions on T cells. Recently, an intronic 7146G/A polymorphism within the PD‐1 gene was described and suggested to be associated with autoimmunity. We investigated whether this genetic polymorphism is a genetic modifier for risk and progression of MS. Blood samples from 939 German MS patients (mean age, 39 years; range, 13–71; 566 patients [60%] with relapsing‐remitting MS, 279 (30%) with secondary, and 94 (10%) with primary progressive MS) and 272 healthy white controls were tested. Genotyping was performed by polymerase chain reaction and restriction enzyme digestion; results were confirmed by automatic sequencing. A significant association of the mutated allele with a progressive disease course was detected (44% 7146G vs 56% 7146A, χ2 p = 0.002). Consequences of the PD‐1 mutation for T‐cell function were assessed ex vivo in some patients using microsphere‐stimulated peripheral blood lymphocytes and purified CD4 cells. Importantly, PD‐1–mediated inhibition of T‐cell cytokine secretion (interferon‐γ) is impaired in patients carrying the PD‐1 polymorphism. In conclusion, our data suggest that PD‐1 polymorphism is a genetic modifier of the progression of MS, possibly through inducing a partial defect in PD‐1–mediated inhibition of T‐cell activation. Ann Neurol 2005
Isothermal crystallization of poly(ethylene‐co‐glycidyl methacrylate)/clay nanocomposites
Authors: Huang Jiann‐Wen , Kang Chiun‐Chia , Chen Tse‐Hsin 
Published: May 2005

AbstractPoly(ethylene‐co‐glycidyl methacrylate) (PEGMA)/clay nanocomposites with clay concentrations of 1, 3, or 5 wt % were prepared via y melt blending in a twin‐screw extruder. Wide‐angle X‐ray diffraction showed that the clay layers were intercalated by PEGMA. Differential scanning calorimetry was used to analyze the isothermal crystallization, and the equilibrium melting temperature was determined with the Hoffman–Weeks method. The Avrami, Tobin, Malkin, and Urbanovici–Segal models were applied to describe the kinetics of crystallization from the melt state under isothermal conditions. The crystallization kinetics showed that the addition of clay facilitated the crystallization of PEGMA, with the clay functioning as a heterophase nucleating agent; at higher concentrations, however, the physical hindrance of the clay layers to the motion of PEGMA chains retarded the crystallization process. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1051–1064, 2005
New composite systems on the base of polyethylene porous films covered by polypyrrole and polyacrylic acid
Authors: Elyashevich G. K. , Rosova E. Yu. , Andreeva D. V. , Polotskaya G. A. , Trchová M. , Pientka Z. 
Published: May 2005

AbstractNew composite systems were prepared by deposition of conducting polymer (polypyrrole) and polyacrylic acid onto polyethylene porous support. Polypyrrole layers were formed by oxidative polymerization from the gas phase of the monomer, and the layers of polyacrylic acid were deposited from a water solution. Morphology of the systems was studied by atomic force microscopy. Measurements of density, electric, and mechanical characteristics of composites were carried out. The interactions between components of systems were investigated by IR spectroscopy. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1410–1417, 2005
Rice husk–polyester composites: The effect of chemical modification of rice husk on the mechanical and dimensional stability properties
Authors: Rozman H. D. , Musa L. , Abubakar A. 
Published: May 2005

AbstractRice husk was used as filler in the production of rice husk (RH)–polyester composites and was subjected to three types of chemical modification. The chemical reagents employed in this study were glycidyl methacrylate (GMA), maleic anhydride (MAH), and succinic anhydride (SAH). This study revealed that the chemical modification of RH with GMA and MAH resulted in the enhancements of tensile and flexural properties of RH–polyester composites. The reduction in these properties with respect to those modified with SAH were attributed to the absence of CC unsaturated groups. Water immersion test showed that chemical modification of the RH improved the dimensional stability of the composites. This was shown in the GMA‐ and MAH‐modified RH–polyester composites. The modification increased the hydrophobicity as well as the crosslinking between the RH and matrix in the composites. The lower performance demonstrated by the SAH‐modified composites was due to the inability of the SAH to form crosslinking with the matrix. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1237–1247, 2005
Proton‐exchange membranes via the grafting of styrene and acrylic acid onto fluorinated ethylene propylene copolymer by a preirradiation technique. IV. Dynamic mechanical analysis, X‐ray diffraction, and scanning electron microscopy studies of grafted and sulfonated membranes
Authors: Phadnis S. , Patri M. , Chakraborty B. C. , Singh P. K. , Deb P. C. 
Published: May 2005

AbstractThe grafting of styrene and acrylic acid onto fluorinated ethylene propylene copolymer was carried out by a preirradiation technique. The resulting membranes were sulfonated with concentrated sulfuric acid. The effects of the degree of grafting and sulfonation on the structure of the membranes were studied by X‐ray diffraction and scanning electron microscopy. The crystallinity percentage decreased with increasing grafting. Scanning electron microscopy studies confirmed that grafting took place by a front mechanism, by which grafting started at the surface and slowly proceeded inwards. The dynamic mechanical properties of the membranes and their sulfonated derivatives were also investigated. The storage modulus at room temperature increased with grafting and increased further with sulfonation. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1426–1431, 2005
Effect of poly(ethylene glycol) on the hydrophobic interactions and rheology of proanthocyanidin biopolymers from Pinus radiata
Authors: Sarathchandra W. D. , Mainwaring D. E. 
Published: May 2005

AbstractThe rheology of solutions of extracts from the bark of Pinus radiata was investigated in the presence of poly(ethylene glycol)s (PEGs) of different molecular weights. PEG with a molecular weight of 4600 (1% w/w) was sufficient to reduce the viscosity of a concentrated (40% w/w) pine tannin extract by one order of magnitude. The reduction of the viscosity was due to the inhibition of molecular association via hydrogen bonding and hydrophobic interactions between tannin and PEG and depended on the molecular weight of PEG. PEG effectively reduced the viscosity of polyphenolic tannins but retained high reactivity toward paraformaldehyde for adhesive formulations. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1254–1260, 2005
Influence of molecular parameters and processing conditions on degradation of hydrogenated nitrile butadiene rubbers
Authors: Chaudhry R. A. , Hussein I. A. , Amin M. B. , Abu Sharkh B. F. 
Published: May 2005

AbstractThe thermomechanical modification of hydrogenated nitrile butadiene rubbers (HNBR) of different molecular parameters was investigated by rheological and light scattering techniques. The influences of acrylonitrile content, degrees of hydrogenation, and Mooney viscosity were examined. A melt blender with Banbury‐type mixing blades was used to condition the rubber samples in the temperature range from 190 to 260°C. Light scattering was used to determine the effect of conditioning on MW and hydrodynamic radius of the rubber molecules. Dynamic viscosity (η′) and storage modulus (G′) were measured for the as‐received and conditioned samples. Experimental results showed that degradation in these rubbers occurred through chain scission and crosslinking. Depending on the molecular parameter, it was found that one of these two mechanisms dominated the degradation process in most brands. Addition of adequate amounts of antioxidants (Irganox 1010 and Irgafos 168) was successful only in preventing degradation by crosslinking. Compared to thermal degradation, thermomechanical degradation was found to be much more severe and progressed at much higher rates. Rheology was found to be a very sensitive technique to structural parameters of the polymers and could be used to detect and identify the mechanism of degradation. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1432–1441, 2005
Comparison of microwave and thermal cure of epoxy–anhydride resins: Mechanical properties and dynamic characteristics
Authors: Tanrattanakul Varaporn , SaeTiaw Kaew 
Published: May 2005

AbstractThe objective of this work was to compare the mechanical properties of epoxy resins cured by thermal heating and microwave heating. Epoxy–anhydride (100:80) resins were cured in a domestic microwave oven and in a thermal oven. The hardening agents included methyl tetrahydrophthalic anhydride and methyl hexahydrophthalic anhydride. Three types of accelerators were employed. Thermal curing was performed at 150°C for 20 and 14 min for resins containing 1 and 4% accelerator, respectively. Microwave curing was carried out at a low power (207 or 276 W) for 10, 14, and 20 min. All cured resins were investigated with respect to their tensile properties, notched Izod impact resistance, and flexural properties (three‐point bending) according to ASTM standards. The tan δ and activation energy values were investigated with dynamic mechanical thermal analysis, and the extent of conversion was determined with differential scanning calorimetry. The differences in the mechanical properties of the thermally cured and microwave‐cured samples depended on the resin formulation and properties. Equivalent or better mechanical properties were obtained by microwave curing, in comparison with those obtained by thermal curing. Microwave curing also provided a shorter cure time and an equivalent degree of conversion. The glass‐transition temperatures (tan δ) of the thermally and microwave‐cured resins were comparable, and their activation energies were in the range of 327–521 kJ/mol. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1442–1461, 2005
Spectrophotometric measurement of swelling of polymer films by very poor solvents
Authors: Stevens F. 
Published: May 2005

AbstractSolvent swelling of polymers is important for many applications, but can be difficult to measure when thin films or very poor solvents are involved. A novel spectrophotometric method is presented that is well suited for measuring swelling of thick or thin polymer films by very poor solvents. In this method, the solvent is stained with iodine, and solvent uptake is measured by observing the change in visible light absorption of the polymer using a spectrophotometer. Using this method, swelling can be accurately measured in thin (< 2 μm) polymer films and with poor solvents that cause little swelling, even water. Results are presented for PMMA films of varying molecular weights swelled by water, by water–alcohol mixtures, and by undiluted alcohols. Swelling of these films is more rapid and more Fickian than has been reported for bulk samples, probably due to differences in PMMA molecular weight and processing. The properties of the iodine–PMMA complex are also explored. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1082–1089, 2005
Effects of the chemical foaming agents, injection parameters, and melt‐flow index on the microstructure and mechanical properties of microcellular injection‐molded wood‐fiber/polypropylene composites
Authors: Bledzki Andrzej K. , Faruk Omar 
Published: May 2005

AbstractWood‐fiber‐reinforced plastic profiles are growing rapidly in nonstructural wood‐replacement applications. Most manufacturers are evaluating new alternative foamed composites, which are lighter and more like wood. Foamed wood composites accept screws and nails better than their nonfoamed counterparts, and they have other advantages as well. For example, internal pressures created by foaming give better surface definition and sharper contours and corners than nonfoamed profiles have. In this study, the microfoaming of polypropylene (PP) containing hardwood fiber was performed with an injection‐molding process. The effects of different chemical foaming agents (endothermic, exothermic, and endothermic/exothermic), injection parameters (the mold temperature, front flow speed, and filling quantity), and different types of PP (different melt‐flow indices) on the density, microvoid content, physicomechanical properties, surface roughness, and microcell classification of microfoamed PP/wood‐fiber composites were studied. A maleic anhydride/polypropylene copolymer (MAH‐PP) compatibilizer was used with the intention of improving the mechanical properties of microfoamed composites. The microcell classification (from light microscopy) and scanning electron micrographs showed that an exothermic chemical foaming agent produced the best performance with respect to the cell size, diameter, and distance. The polymer melt‐flow index and the variation of the injection parameters affected the properties and microstructure of the microfoamed composites. The density of the microfoamed hardwood‐fiber/PP (with a high melt‐flow index) composites was reduced by approximately 30% and decreased to 0.718 g/cm3 with an exothermic chemical foaming agent. Tensile and flexural tests were performed on the foamed composites to determine the dependence of the mechanical properties on the density and microvoid content of the foamed specimens, and these properties were compared with those of nonfoamed composites. MAH‐PP improved the physicomechanical properties up to 80%. With an increase in the mold temperature (80–110°C), the surface roughness was reduced by nearly 70% for the foamed composites. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1090–1096, 2005
Lamination of high‐density polyethylene by bulk photografting and the mechanism of adhesion
Authors: Wang Huiliang , Brown Hugh R. 
Published: May 2005

AbstractThe photolamination of high‐density polyethylene (HDPE) by bulk photografting is described, along with a discussion of the adhesion mechanism. HDPE can be photolaminated very easily with a thin poly(acrylic acid) layer, photopolymerized from acrylic acid, with very strong adhesion obtained after a short time of UV irradiation; the adhesion failure mode is polyethylene breakage. Thicker HDPE sheets require longer irradiation times for strong adhesion. Methacrylic acid or hydroxyethyl methacrylate provides no adhesion of HDPE at all after irradiation. When glycidyl acrylate is used alone between HDPE sheets, the peel strength of the photolaminated polyethylene is only approximately 320 N/m, but when glycidyl acrylate or hydroxyethyl methacrylate is grafted with acrylic acid, very good adhesion can be obtained. It is proposed that stronger adhesion is produced by a less branched grafted chain structure, which permits much more chain entanglement. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1097–1106, 2005
Crystallization behavior of poly(butylene succinate)/corn starch biodegradable composite
Authors: Ohkita Tsutomu , Lee Seung‐Hwan 
Published: May 2005

AbstractThe effects of corn starch (CS) filler and lysine diisocyanate (LDI) as a coupling agent on the crystallization behavior of a poly(butylene succinate) (PBS)/CS ecocomposite were investigated using differential scanning calorimetry. In isothermal crystallization, n values for pure PBS were from 2.33 to 2.82. On the other hand, both composites showed values of 3 < n < 4. In nonisothermal crystallization, the Avrami exponent varied from 2.12 to 2.55 for pure PBS, from 1.58 to 1.96 for the composite without LDI, and from 1.79 to 1.91 for the composite with LDI, depending on the cooling rate. There was not a large difference of the crystallization rate constant (k) as adjusted by the Jeziornay suggestion. The activation energy for nonisothermal crystallization was also calculated on the basis of three different equations (Augis–Bennett, Kissinger, and Takhor equations). However, the values of the activation energy were in contradiction with the results of the kinetics. The addition of the filler (CS) and coupling agent (LDI) affected the morphological structure of PBS spherulites. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1107–1114, 2005
Preparation, characterization, and drug‐release properties of poly(N‐isopropylacrylamide) microspheres having poly(itaconic acid) graft chains
Authors: Taşdelen Betül , Kayaman‐Apohan Nilhan , MISIrlI Zülal , Güven Olgun , Baysal Bahattin M. 
Published: May 2005

AbstractAn inverse suspension polymerization method for the preparation of thermoresponsive hydrogel microspheres based on N‐isopropylacrylamide was described in this article. The polymerization reaction was carried out at 200 rpm stirring rate and the microspheres obtained were in the size range of 71–500 μm in the swollen states. The particles were sieved by using ASTM sieves. The selected fraction (180–250 μm) of poly(N‐isopropylacrylamide) (PNIPAAm) microspheres was used for radiation‐induced modification with itaconic acid (IA) to obtain PNIPAAm/poly(itaconic acid) graft copolymer. Viagra and lidocaine were used as model drugs for the investigation of controlled‐release behavior of the microspheres. Incorporation of IA graft chains onto microspheres enhanced significantly the uptake of both drugs and further controlled release at specific pH values. The release studies showed that some of the basic parameters affecting the drug‐loading and ‐release behavior of the microspheres were pH, temperature, particle size, and chemical nature of drug. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1115–1124, 2005
Mechanical properties of deproteinized natural rubber in comparison with synthetic cis‐1, 4 polyisoprene vulcanizates: Gum and black‐filled vulcanizates
Authors: Rattanasom N. , Thammasiripong U. , Suchiva K. 
Published: May 2005

AbstractGum and black‐filled vulcanizates having various crosslink densities were prepared from 2 types of rubber, namely, deproteinized natural rubber (DPNR) and synthetic cis‐1, 4 polyisoprene vulcanizates (IR). Their mechanical properties, such as tensile strength, tear strength, abrasion loss, and heat buildup resistance, at various crosslink densities as well as at similar optimum crosslink density were compared. For both gum and black‐filled systems, IR possessed a higher crosslink density than that of DPNR at a fixed curative content. Tensile and tear strength of all vulcanizates passed through a maximum with increasing crosslink density. For gum vulcanizates, tensile and tear strengths of DPNR and IR below the maximum were not much different. However, IR had a narrower tear strength peak relative to DPNR. At a comparable optimum crosslink density, DPNR exhibited higher tensile strength and crack growth resistance than IR. For black‐filled vulcanizates, tensile and tear strengths, and heat buildup resistance of DPNR and IR at a given crosslink density were similar. The results revealed that the properties of gum samples were more dependent upon crosslink density than the black‐filled ones because the reinforcement by carbon black overshadowed the intrinsic properties of the rubbers. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1139–1144, 2005