bluuebunny/crossref_metadata_2025_split huggingface dataset:
Homocysteine, silent brain infarcts, and white matter lesions: The Rotterdam scan study
Authors: Vermeer Sarah E. , Van Dijk Ewoud J. , Koudstaal Peter J. , Oudkerk Matthijs , Hofman Albert , Clarke Robert , Breteler Monique M.B. 
Published: August 2002

AbstractSilent brain infarcts and white matter lesions are frequently seen on magnetic resonance imaging in healthy elderly people and both are associated with an increased risk of stroke and dementia. Plasma total homocysteine may be a potentially modifiable risk factor for stroke and dementia. We examined whether elevated total homocysteine levels are associated with silent brain infarcts and white matter lesions. The Rotterdam Scan Study is a population‐based study of 1,077 people aged 60 to 90 years who had cerebral magnetic resonance imaging. The cross‐sectional relation of total homocysteine with silent infarcts and white matter lesions was analyzed with adjustment for cardiovascular risk factors. The mean plasma total homocysteine level was 11.5μmol/l (standard deviation 4.1). The risk of silent brain infarcts increased with increasing total homocysteine levels (odds ratio 1.24/standard deviation increase, 95% confidence interval 1.06–1.45). The severity of periventricular white matter lesions and extent of subcortical white matter lesions were also significantly associated with total homocysteine levels, even after excluding those with silent brain infarcts. The overall risk of having either a silent brain infarct or severe white matter lesions was strongly associated with total homocysteine levels (odds ratio 1.35/standard deviation increase, 95% confidence interval 1.16–1.58). We concluded that total homocysteine levels are associated with silent brain infarcts and white matter lesions independent of each other and of other cardiovascular risk factors.
Synthesis, characterization, coordination and antibacterial properties of novel asymmetric 1,1′‐disubstituted ferrocene‐derived Schiff‐base ligands and their Co(II), Cu(II) Ni(II) and Zn(II) complexes
Authors: Chohan Zahid H. , Praveen M. 
Published: August 2002

AbstractSome new asymmetric 1,1′‐disubstituted ferrocene‐derived Schiff‐bases have been prepared and used as ligands in the preparation of their Co(II), Cu(II), Ni(II) and Zn(II) metal chelates. These synthesized ligands and their metal chelates have been characterized by their physical, analytical and spectral data. These have also been used for screening against pathogenic bacterial species, e.g. Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella pneumonae and have been found to be a novel class of organometallic‐based antibacterials. Copyright © 2001 John Wiley & Sons, Ltd.
Synthesis of polymeric precursors for the formation of nanocrystalline Ti‐C‐N/amorphous Si‐C‐N composites
Authors: Hering Nicole , Schreiber Kai , Riedel Ralf , Lichtenberger Olaf , Woltersdorf Jörg 
Published: August 2002

AbstractThe synthesis of trimethylsilyl‐substituted poly(titaniumcarbodiimide) as a novel precursor for titanium carbonitride based ceramic materials is described. The precursor and the subsequent processing steps (cross‐linking and pyrolysis) are characterized by IR and Raman spectroscopy, thermal gravimetric analysis and simultaneous mass spectroscopy, electron microscopy and powder X‐ray diffraction measurements. The novel polymer is formed by the reaction of TiCl4 or Ti(NEt2)4 with bis(trimethylsilyl)carbodiimide. Subsequent pyrolysis at 1000 °C in argon results in the formation of a ceramic composite material consisting of nanocrystalline TiCN and amorphous SiCN as constituting phases. Using Ti(NEt2)4 as a starting reagent instead of TiCl4, chlorine contamination of the ceramic material can be avoided. The different molecular vibration modes of the metal–nitrogen, metal–carbon and nitrogen–carbon bonds in poly(titaniumcarbodiimides) with trimethylsilyl substituents were calculated using quantum mechanical methods, providing a comprehensive understanding of the measured spectra. Copyright © 2001 John Wiley & Sons, Ltd.
Hydrogenation and neutralization of carboxylic styrene–butadiene latex to form thermoplastic elastomer with excellent thermooxidation resistance
Authors: Xie Hong‐Quan , Li Xiao‐Dong , Liu Xiang‐Yao , Guo Jun‐Shi 
Published: August 2002

AbstractHydrogenation of carboxylic styrene–butadiene rubber latex was carried out using hydrazine and hydrogen peroxide with ferrous sulfate as a catalyst without pressurized hydrogen and an organic solvent. A mixed inhibitor was used during hydrogenation to prevent gel formation. Various hydrogenation conditions were studied. Ferrous sulfate is better than is cupric sulfate as a catalyst. The hydrogenation degree can reach over 90%. The hydrogenated product was characterized by IR and DSC. The hydrogenated products behave as a thermoplastic elastomer with excellent thermooxidation resistance, due to the absence of most double bonds and the presence of crystalline domains of polyethylene segments formed by the hydrogenation of polybutadiene segments. Ionomers were obtained by neutralization of the hydrogenated product with metallic ions and characterized by IR, DSC, and TEM. The ionomers also behave as thermoplastic elastomers with mechanical properties better than those of the hydrogenated product without neutralization, due to the existence of ionic domains besides the crystalline domains. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1375–1384, 2002
Permeation of drugs in chitosan membranes
Authors: Rocha A. N. L. , Dantas T. N. C. , Fonseca J. L. C. , Pereira M. R. 
Published: August 2002

AbstractThe permeabilities of isoniazid and amitriptyline hydrochloride in chitosan membranes were investigated. Drug concentration was changed from 0.1 to 1.0% while membrane thickness was varied from 40 to 150 μm. The release rate was measured in water at 30 ± 0.1°C by spectrophotometric determination. The drugs presented quite different permeabilities, which were related to their molecular weights; the permeabilities did not change with thickness or drug concentration for the ranges investigated. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 44–49, 2002; DOI 10.1002/app.10185
Comparison of the structure of step‐growth networks obtained by Monte Carlo simulation and branching theory
Authors: Hädicke Erich , Stutz Herbert 
Published: August 2002

AbstractTo facilitate the characterization of polymer networks, a comparison was made between branching theory and Monte Carlo simulations using an amine‐cured epoxy as an example for step‐growth polymer networks. The primary objective was the validation of the simulation results with the existing statistical theories by a cross‐check, to ensure that simulations can also be used for the characterization of real, highly complicated multicomponent systems, which are intractable by theories. Commercially available software was used for simulation; the theoretical calculations were performed using the approach of Macosko and Miller. In general, the results of both methods are consistent; the simulation revealed some uncertainties only in the vicinity of the gel point. Since the statistical theories have been validated experimentally, it may be concluded that the simulation can also successfully be used for the treatment of real, highly complicated multicomponent systems, which for practical purposes are intractable by statistical theories. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 929–935, 2002
Three‐dimensionally braided carbon fiber–epoxy composites, a new type of materials for osteosynthesis devices. II. Influence of fiber surface treatment
Authors: Wan Y. Z. , Wang Y. L. , Zhou F. G. , Cheng G. X. , Han K. Y. 
Published: August 2002

AbstractInterfacial adhesion between carbon fiber and epoxy resin plays an important role in determining performance of carbon–epoxy composites. The objective of this research is to determine the effect of fiber surface treatment (oxidization in air) on the mechanical properties (flexural strength and modulus, shear and impact strengths) of three‐dimensionally (3D) braided carbon‐fiber‐reinforced epoxy (C3D/EP) composites. Carbon fibers were air‐treated under various conditions to improve fiber–matrix adhesion. It is found that excessive oxidation will cause formation of micropits. These micropits are preferably formed in crevices of fiber surfaces. The micropits formed on fiber surfaces produce strengthened fiber–matrix bond, but cause great loss of fiber strength and is probably harmful to the overall performance of the corresponding composites. A trade‐off between the fiber–matrix bond and fiber strength loss should be considered. The effectiveness of fiber surface treatment on performance improvement of the C3D/EP composites was compared with that of the unidirectional carbon fiber–epoxy composites. In addition, the effects of fiber volume fraction (Vf) and braiding angle on relative performance improvements were determined. Results reveal obvious effects of Vf and braiding angle. A mechanism was proposed to explain the experimental phenomena. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1040–1046, 2002
Distribution of carbon black in semicrystalline polypropylene studied by transmission electron microscopy
Authors: Feng Jiyun , Li Jianxiong , Chan Chi‐Ming 
Published: August 2002

AbstractPolypropylene (PP) samples filled with different carbon blacks (CB) were prepared by the conventional melt‐mixing method. The distribution of the CB in the PP matrix was investigated by using the RuO4 vapor‐staining technique and transmission electron microscopy (TEM). Our results indicate that amorphous regions of PP are sandwiched between the crystalline lamellae. The thickness of individual amorphous layers is a few nanometers. The amorphous region was measured to be about 45 wt % using a differential scanning calorimeter (DSC). The thickness of the lamellae is much smaller than the dimensions of the CB particles, and the CB particles or aggregates are dispersed inside the spherulites. There is a thin layer of amorphous PP encapsulating the CB particles and aggregates. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 358–365, 2002
Effects of composition and temperature on extrudate characteristics, morphology, and tensile properties of acrylic rubber–blended PVC
Authors: Wimolmala E. , Wootthikanokkhan J. , Sombatsompop N. 
Published: August 2002

AbstractPoly(vinyl chloride) was blended with acrylic rubber over a range of compositions (5–40 wt % of the rubber), using a twin‐screw extruder. Morphological properties of the blends were investigated as a function of rubber content and blending temperature, using a scanning electron microscopy. The mechanical properties of the blends were determined by a tensile test. Smooth extrudates were obtained at the blending temperature of 155°C. At a higher blending temperature (195°C), greater die swell ratio and/or melt‐fractured extrudates were observed, depending on the rubber content. Miscible blends were obtained at low rubber contents (5–10 wt %). A dispersed particle morphology was observed from the extrudates containing the rubber content of 20–40 wt %, at 195°C. The ultimate tensile stress (UTS) and modulus of the blends decreased with the rubber content. The maximum tensile toughness was obtained for the blend with a rubber content of 20%, at a blending temperature of 155°C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2523–2534, 2001
Synthesis and characterization of triallylphenoxytriazine and the properties of its copolymer with bismaleimide
Authors: Fang Qiang , Jiang Luxia 
Published: August 2002

AbstractA new modifier for bismaleimide (BMI), 2,4,6‐tris(2‐allylphenoxy)‐1,3,5‐triazine (TAPT), with higher yield was prepared by a phase‐transfer catalyzing (PTC) procedure through the reaction of cyanuric chloride with 2‐allylphenol in the presence of aq. NaOH using tetrabutyl ammonium bromide in chloroform. The thermo‐homopolymerization behavior of TAPT was investigated by differential scanning calorimetry (DSC), and the results showed that TAPT does not polymerize on heating. The copolymerization reaction of TAPT and 4,4'–(bismaleimidophenyl) methane (BMDPM) was also studied. and the results showed that TAPT can effectively improve mechanical properties of BMDPM. The better results were obtained when the TAPT composition was in the range 30–40 wt %. The glass fabric reinforced TAPT/BMDPM matrix composite with excellent mechanical and electric properties could be prepared by processing the resin (30 wt % TAPT) in dimethylformamide (DMF)/toluene (1:1, v/v) solution. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1248–1257, 2001
Microporous membranes of polyoxymethylene from a melt‐extrusion process: (I) effects of resin variables and extrusion conditions
Authors: Johnson Matthew B. , Wilkes Garth L. 
Published: August 2002

AbstractA two‐part study utilizing polyoxymethylene (POM) was undertaken to investigate a three stage process (melt extrusion/annealing/uniaxial stretching) (MEAUS) employed to produce microporous films. In this first part, three POM resins (D, E, and F) were melt extruded into tubular films (blowup ratio; BUR = 1), where resin D has a higher weight average molecular weight (Mw) than resin E, but both possess similar and relatively narrow molecular‐weight distributions (MWD). In contrast, resin F is characterized by a distinctly broader MWD while its Mw is slightly higher than resin D. Specific attention was focused upon the morphological and crystal orientation results as a function MWD and Mw. A stacked lamellar morphology was obtained in each case from the melt extrusion; however, the type of stacked lamellar morphology, planar or twisted, and the orientation state was found to depend upon both the resin characteristics and the melt‐extrusion conditions. Atomic force microscopy and wide‐angle X‐ray scattering were the main techniques utilized to study the melt‐extruded films while dynamic melt rheometry in conjunction with the Carreau‐Yasuda model aided in differentiating the melt‐flow behavior of the three resins. Small‐angle light scattering (SALS) was also employed to characterize the morphological state. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2944–2963, 2001
Anatomy and three‐dimensional reconstructions of the brain of a bottlenose dolphin (Tursiops truncatus) from magnetic resonance images
Authors: Marino Lori , Sudheimer Keith D. , Murphy Timothy L. , Davis Kristina K. , Pabst D. Ann , McLellan William A. , Rilling James K. , Johnson John I. 
Published: August 2002

AbstractCetacean (dolphin, whale, and porpoise) brains are among the least studied mammalian brains because of the formidability of collecting and histologically preparing such relatively rare and large specimens. Magnetic resonance imaging offers a means of observing the internal structure of the brain when traditional histological procedures are not practical. Furthermore, internal structures can be analyzed in their precise anatomic positions, which is difficult to accomplish after the spatial distortions often accompanying histological processing. In this study, images of the brain of an adult bottlenose dolphin, Tursiops truncatus, were scanned in the coronal plane at 148 antero‐posterior levels. From these scans a computer‐generated three‐dimensional model was constructed using the programs VoxelView and VoxelMath (Vital Images, Inc.). This model, wherein details of internal and external morphology are represented in three‐dimensional space, was then resectioned in orthogonal planes to produce corresponding series of virtual sections in the horizontal and sagittal planes. Sections in all three planes display the sizes and positions of major neuroanatomical features such as the arrangement of cortical lobes and subcortical structures such as the inferior and superior colliculi, and demonstrate the utility of MRI for neuroanatomical investigations of dolphin brains. Anat Rec 264:397–414, 2001. © 2001 Wiley‐Liss, Inc.
Role of specific activators of intestinal amino acid transport in Bombyx mori larval growth and nutrition
Authors: Leonardi M. Giovanna , Casartelli Morena , Fiandra Luisa , Parenti Paolo , Giordana Barbara 
Published: August 2002

AbstractNutrient absorption and its modulation are critical for animal growth. In this paper, we demonstrate that leucine methyl ester (Leu‐OMe) can greatly increase the activity of the transport system responsible for the absorption of most essential amino acids in the larval midgut of the silkworm Bombyx mori. We investigated leucine uptake activation by Leu‐OMe in brush border membrane vesicles and in the apical membrane of epithelial cells in the midgut incubated in vitro. Moreover, the addition of this strong activator of amino acid absorption to diet significantly affected larval growth. Silkworms fed on artificial diet supplemented with Leu‐OMe reached maximum body weight 12–18 h before control larvae, and produced cocoon shells up to 20% heavier than those of controls. The activation of amino acid absorption plays an essential role in larval development so that larval growth and cocoon production similar to controls reared on an artificial diet with 25% of dry mulberry leaf powder were observed in silkworms fed on an artificial diet with only 5% of mulberry powder. Arch. Insect Biochem. Physiol. 48:190–198, 2001. © 2001 Wiley‐Liss, Inc.
Exploring the etiology of haploinsufficiency
Authors: Veitia Reiner A. 
Published: August 2002

AbstractThe focus of this essay is the phenomenon of haploinsufficiency (HI), a manifestation of genetic dominance that arises when only one allele of a normally diploid locus is present. Specifically, I examine the nature of HI for transcription factor genes. Although the concept of HI applies to many such genes, there is a potentially large variety of mechanisms that underlie it. Even when the phenomenon is linked in all cases to reduced absolute gene expression levels, there are several well‐documented cases where the explanation is not reduced expression per se but altered stoichiometry. I will discuss the notion of haploimbalance in general and evaluate the property of transcriptional synergy within the context of HI. This kind of non‐linear behaviour can probably explain a large proportion of the cases of HI, as well as the variability in most HI phenotypes and the fact that several factors in the same pathway may be dosage sensitive. For the sake of generality, a theoretical analysis of simple non‐linear HI systems is also attempted. This article is certainly another preliminary exploration of the complex matters of HI, which remain an intellectual challenge from many points of view. BioEssays 24:175–184, 2002. © 2002 Wiley Periodicals, Inc.
Mechanisms of the antitumoral effect of lipid A
Authors: Reisser Danièle , Pance Alena , Jeannin Jean‐François 
Published: August 2002

AbstractBacterial lipopolysaccharide (LPS) and its active component, lipid A, have been used either alone or as adjuvant in therapeutic anticancer vaccines. Lipid A induces various transcription factors via intracellular signaling cascades initiated by their receptor CD14‐TLR4. These events lead to the synthesis of cytokines, which either have direct cytotoxic effect or stimulate the immune system. Their antitumoral effect has been demonstrated in animal models as well as clinical trials. Studies in animal models showed that their antitumoral effect relies mostly on the generation of an effective immune response. In humans, the antitumoral effect was correlated with an antibody response and cell‐mediated cytotoxicity. So far, some encouraging results have been achieved in phase I and II clinical trials with regards to response and stabilization of the disease, but an expansion of the studies and trials is needed to find the best conditions for their clinical application. BioEssays 24:284–289, 2002. © 2002 Wiley Periodicals, Inc.; DOI 10.1002/bies.10053
Effect of sodium chloride on the gelatinization of starch: A multimeasurement study
Authors: Chiotelli Eleni , Pilosio Giorgio , Le Meste Martine 
Published: August 2002

AbstractThe effect of sodium chloride on the gelatinization and rheological properties of wheat and potato starches has been studied using differential scanning calorimetry, dynamic mechanical thermal analysis, and electron spin resonance techniques. All samples contained 60% water (w/w wet starch basis) and the salt content ranged from 0 to 16% (g/100 g starch–water). The presence of salt affected the onset (To), peak (Tp), and end (Te) temperatures of gelatinization, gelatinization enthalpy (ΔH), storage modulus (G′), and rotational mobility coefficient (Drot), and the effect differed by salt concentration. 1H‐NMR was used in parallel in order to elucidate how salts affect the properties of water in starch suspensions and in aqueous salt solutions according to their position on the Hofmeister series classification. The obtained results suggest that the mechanism of starch gelatinization in salt solutions can be attributed to the effect of solute on water properties and direct polymer–solute interactions. These two effects conflict with one another and result in complex effect patterns depending on the concentration of the salts. © 2002 John Wiley & Sons, Inc. Biopolymers 63: 41–58, 2002
Synthesis of phosphatidylcholine with defined fatty acid in the sn‐1 position by lipase‐catalyzed esterification and transesterification reaction
Authors: Adlercreutz Dietlind , Budde Heike , Wehtje Ernst 
Published: August 2002

AbstractThe incorporation of caproic acid in the sn‐1 position of phosphatidylcholine (PC) catalyzed by lipase from Rhizopus oryzae was investigated in a water activity‐controlled organic medium. The reaction was carried out either as esterification or transesterification. A comparison between these two reaction modes was made with regard to product yield, product purity, reaction time, and byproduct formation as a consequence of acyl migration. The yield in the esterification and transesterification reaction was the same under identical conditions. The highest yield (78%) was obtained at a water activity (aw) of 0.11 and a caproic acid concentration of 0.8 M. The reaction time was shorter in the esterification reaction than in the transesterification reaction. The difference in reaction time was especially pronounced at low water activities and high fatty acid concentrations. The loss in yield due to acyl migration and consequent enzymatic side reactions was around 16% under a wide range of conditions. The incorporation of a fatty acid in the sn‐1 position of PC proved to be thermodynamically much more favorable than the incorporation of a fatty acid in the sn‐2 position. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 403–411, 2002.