bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neuroplasticity in old age: Sustained fivefold induction of hippocampal neurogenesis by long‐term environmental enrichment
Authors: Kempermann Gerd , Gast Daniela , Gage Fred H. 
Published: October 2002

AbstractNeurons are continually born from endogenous stem cells and added to the dentate gyrus throughout life, but adult hippocampal neurogenesis declines precipitously with age. Short‐term exposure to an enriched environment leads to a striking increase in new neurons, along with a substantial improvement in behavioral performance. Could this plastic response be relevant for explaining the beneficial effects of leading “an active life” on brain function and pathology? Adult hippocampal neurogenesis in mice living in an enriched environment from the age of 10 to 20 months was fivefold higher than in controls. Relatively, the increase in neuronal phenotypes was entirely at the expense of newly generated astrocytes. This cellular plasticity occurred in the context of significant improvements of learning parameters, exploratory behavior, and locomotor activity. Enriched living mice also had a reduced lipofuscin load in the dentate gyrus, indicating decreased nonspecific age‐dependent degeneration. Therefore, in mice signs of neuronal aging can be diminished by a sustained active and challenging life, even if this stimulation started only at medium age. Activity exerts not only an acute but also a sustained effect on brain plasticity.
Full‐range kinetic study on bulk syndiotactic polymerization of styrene with homogeneous metallocene catalysis
Authors: Fan Rong , Li Bo‐Geng , Cao Kun , Zhou Wen‐Le , Shen Zhi‐Gang , Ye Meng 
Published: October 2002

AbstractBy choosing a proper agitator and reinforcing its stirring shear, powdery syndiotactic polystyrene (sPS) is prepared in a bulk precipitation process with two homogeneous metallocene catalyst systems [Cp*TiX3/MAO/TIBA (X = Cl or OPhOMe)]. A full‐range kinetics study of the heterogeneous polymerization is performed in detail to produce this kind of powdery sPS in an industrial process. A typical curve of conversion versus time takes an S shape and an obvious acceleration phenomenon occurs in the middle stage of the polymerization, although the polymer–monomer gel is avoided. The viscous‐average molecular weight of sPS goes through a peculiar increasing–decreasing–increasing change during the bulk polymerization process. These phenomena are viewed in terms of the two‐phase polymerization mechanism and the overheating in particles during polymerization. The influence of the metallocene catalyst type and concentration, MAO/Ti ratio, triisobutyl aluminum (TIBA)/Ti ratio, and polymerization temperature on the polymerization kinetics are investigated. TIBA has dual effects on the polymerization. A small amount of TIBA in the catalyst system promotes polymerization, but more TIBA leads to a low molecular weight sPS. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2635–2643, 2002
In situ sol‐gel process of polystyrene/silica hybrid materials: Effect of silane‐coupling agents
Authors: Jang Jyongsik , Park Hwanseok 
Published: October 2002

AbstractThe polystyrene–silica hybrid materials have been successfully prepared from styrene and tetraethoxysilane in the presence of silane‐coupling agents by an in situ sol‐gel process. Triethoxysilyl group can be incorporated into polystyrene as side chains by the free‐radical copolymerization of polystyrene with silane‐coupling agents, and simultaneously polystyrene–silica hybrid materials with covalent bonds between two phases were formed via the sol‐gel reaction. The 3‐(trimethoxysilyl)‐propyl‐methacrylate (MPS) systems were found to be more homogeneous than the corresponding allytrimethoxysilane hybrid system of equal molar content. In the MPS‐introduced system, the thermal properties of the materials were greatly affected by the presence of MPS. FTIR results indicate successful formation of the silica networks and covalent bonding formation of coupling agents with styrene. The homogeneity of polystyrene–silica systems was examined by scanning electron microscope and atomic force microscope. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2074–2083, 2002
Influences of some polymerization conditions on particle properties of suspension poly(vinyl chloride) resin
Authors: Bao Y. Z. , Brooks B. W. 
Published: October 2002

AbstractEffects of polymerization temperature, conversions, and nonionic surfactant on the particle properties of suspension poly(vinyl chloride) (PVC) resins were investigated. It was shown that polymerization temperature has no significant influences on the mean particle size of PVC resin, and that the cold plasticiser absorption (CPA) of resin decreases linearly with the increase of polymerization temperature. Agglomeration of VCM droplets finishes before 20% conversion, and the mean particle size keeps almost constant at later stages of the polymerization process, but the CPA continues decreasing with the increase of conversion. Scanning Electron Microscopy (SEM) micrographs show that the degree of agglomeration of primary particles increases with polymerization temperature and conversion. Addition of nonionic surfactant to the VCM suspension system, as a secondary suspending agent, has a great influence on the particle properties of PVC resin. The particle size and CPA increase as the concentration of nonionic surfactant increases. The nonionic surfactant with a greater HLB value is more effective in raising the mean particle size, but is less effective in raising the CPA. It is considered that the added nonionic surfactant would be absorbed faster on the VCM/water interface than the poly(vinyl alcohol) (PVA), which was used as the primary suspending agent. Because the colloid protection ability of the nonionic surfactant is less than that of PVA, droplets become less resistant to coalescence, and the mean particle size of the final PVC resin increases consequently. The increase of porosity is caused by the combined effects of increased coalescence of VCM droplets and the nonionic surfactant's steric effect inside the droplets. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1544–1552, 2002
Synthesis and characterization of water‐soluble polymeric adhesion promoter for epoxy resin/copper joints
Authors: Song S. M. , Cho K. , Park C. E. , Yun H. K. , Oh S. Y. 
Published: October 2002

AbstractNobel polymeric adhesion promoter soluble in water was synthesized to improve the adhesion strength of copper lead frame/epoxy molding compound (EMC) joints. N‐(4‐phenolyl)‐(benzotriazole‐5‐carboxylic)amide (PBCA) was synthesized by reacting benzotriazole‐5‐carboxylic acid (CBTA) with 4‐aminophenol. Poly[acrylic‐co‐4‐(5‐benzotriazole)amido phenyl acrylate] (PAB) was synthesized by reacting poly acryloyl chloride with PBCA. The adhesion strength of PAB‐treated copper lead frame/epoxy resin joints increased with the increase of PBCA content in PAB by forming more Cu‐triazole complex. The adhesion strength of PAB‐treated copper lead frame/epoxy resin joints having high PBCA content in PAB (more than 0.3 of mole ratio) is comparable to that of polybenzimidazole (PBI)‐treated copper lead frame/epoxy resin joints. However, the adhesion strength of PAB‐treated copper/epoxy resin joints decreased with the increase of PAB treatment time since Cu‐triazole complex particles were formed on PAB‐treated copper surface and acted as defects. The initial adhesion strength was maintained by suppressing the formation of Cu‐triazole complex particles using PAB having low PBCA contents (0.003 mole ratio of PBCA). The solubility of PAB in water was dependent on the mole ratio of carboxylic acid to PBCA in PAB. The increase of carboxylic acid content in PAB improved the solubility of PAB in water but decreased the adhesion strength with copper. PAB containing 0.03 mole ratio of PBCA was soluble in water. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2202–2210, 2002
Curing of crust leather by ultraviolet radiation with urethane acrylate: Role of pigment
Authors: Khan Mubarak A. , Rahman M. Mizanur , Bhuyan M. Z. R. , Ahmad M. U. 
Published: October 2002

AbstractEight different formulations were developed with four diacrylate reactive monomers such as tripropylene glycol diacrylate (TPGDA), 1,4‐butanediol diacrylate (BDDA), 1,6‐hexanediol diacrylate (HDDA), and 2‐ethylene glycol dimethacrylate (EGDMA) and aromatic urethane diacrylate (M1100) in order to modify the crust leather surface. To study the effect of pigment on the performance of ultraviolet (UV)‐cured leather surface, 1% pigment (congored) was incorporated in the formulations. Irgacure 369 (2%) was also used in the formulation as photoinitiator. The gel content, tensile strength, elongation at break, and pendulum hardness of UV‐cured thin films with and without pigment was studied. The films without pigment produced better properties. Among all the diluents, BDDA‐containing films showed the best performance. Different properties of UV‐coated leather surface such as pendulum hardness, tensile strength, elongation, gloss (at 20° and 60°), adhesion, and abrasion were studied. Effect of gloss on simulating weathering was also performed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 692–697, 2002
Mechanical properties and morphology of poly(ethylene glycol)‐side‐chain‐modified bismaleimide polymer
Authors: Chian K. S. , Du X. Y. , Goy H. A. , Feng J. L. , Yi S. , Yue C. Y. 
Published: October 2002

AbstractTwo maleimido‐end‐capped poly(ethylene glycol) (m‐PEG)‐modified bismaleimide (BMI) resins [4,4′‐bismaleimido diphenylmethane (BDM)] were synthesized from poly(ethylene glycol) (PEG) of two different molecular weights. A series of m‐PEGs and unmodified BDM were blended and thermally cured. The effect of incorporating m‐PEG side chains on the morphology and mechanical behaviors of BMI polymer were evaluated. The mechanical properties of these m‐PEG‐modified BMIs that were evaluated included flexural modulus, flexural strength, strain at break, fracture toughness, and fracture energy. The morphology of these blends was studied with scanning electron microscopy. All the m‐PEG‐modified BMI polymers showed various degrees of phase separation depending on the molecular weights and concentrations of the m‐PEG used. The effects of these morphological changes in the m‐PEG‐modified BMI polymers were reflected by the improved fracture toughness and strain at break. However, there was a reduction in the flexural moduli in all m‐PEG‐modified BMI polymers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 715–724, 2002
Cloning and characterization of Acmar1, a mariner‐like element in the asiatic honey bee, Apis cerana japonica (Hymenoptera, Apocrita)
Authors: Sumitani Megumi , Lee Jae Min , Hatakeyama Masatsugu , Oishi Kugao 
Published: October 2002

AbstractA mariner‐like element was cloned from the genome of the Asiatic honey bee, Apis cerana japonica (Hymenoptera, Apocrita). The (composite) clone, named Acmar1, was 1,378 bp long, and encoded 336 amino acids corresponding to a transposase‐like putative polypeptide in a single open reading frame. The D,D(34)D motif, the catalytic domain of the mariner transposase, was present, although there was a deletion of five amino acid residues within it as compared with the active transposase in Drosophila mauritiana. Nineteen‐bp‐long imperfect inverted terminal repeat‐like sequences flanked by TA dinucleotides, the typical target site for mariner insertion, were observed. Southern blot analysis using a fragment covering two‐thirds of the Acmar1 transposase coding sequence as a probe indicated the presence of multiple Acmar1‐like elements in the genome. Maximum‐parsimony phylogenetic analysis based on the transposase amino acid sequences of insect mariner‐like elements revealed that Acmar1 is a member of the mellifera subfamily. Arch. Insect Biochem. Physiol. 50:183–190, 2002. © 2002 Wiley‐Liss, Inc.
Purification and characterization of acetylcholinesterase from cotton aphid (Aphis gossypii Glover)
Authors: Li Fei , Han Zhaojun 
Published: October 2002

AbstractA simple and effective method was set up to purify acetylcholinesterase (AChE, EC3.1.1.7) from the cotton aphid, Aphis gossypii Glover. The procedure involved filtration on a sephadex G‐25 column, separation with sephadex G‐200 and procainamide affinity column. AChE from both susceptible and resistant strains were purified to a single band as resolved on denaturing polyacrylamide gel electrophoresis (SDS‐PAGE). The specific activity increased by 35,100‐ and 33,680‐fold with a yield of 30.3 and 29.8%, respectively. The molecular mass of the purified AChE was about 63,500 Dalton as determined by SDS‐PAGE. However, three bands resolved on PAGE gel electrophoresis, leading to the inference that native AChE exists in three forms. The optimum conditions for measuring the activity of purified AChE with kinetic method were 0.02M phosphate buffer, pH7.2, 0.02 mM 5,5′‐dithiobis‐(2‐nitrobenzoic acid) (DTNB), and 25°C. Investigation also revealed that crude extract and purified AChE had different kinetic characteristics and inhibitory properties. They responded differently to varied DTNB, ATChI, and phosphate buffer ion concentrations, as well as pH, temperature, and inhibitors. The purified AChE was more sensitive to eserine, methamidophos, and pirimicarb. Especially for resistant aphids, the sensitivity of purified AChE to methamidophos and pirimicarb was enhanced 6.43 and 11.73 times, respectively. We infer that one or more factors in the crude extract from the resistance strain have more influence on AChE sensitivity. Further study is needed to investigate the basis of these observations. Arch. Insect Biochem. Physiol. 51:37–45, 2002. © 2002 Wiley‐Liss, Inc.
Eicosanoids mediate Manduca sexta cellular response to the fungal pathogen Beauveria bassiana: A role for the lipoxygenase pathway
Authors: Lord, Jeffrey C. , Anderson Sheri , Stanley David W. 
Published: October 2002

AbstractMany studies have documented the involvement of eicosanoids in insect cellular immune responses to bacteria. The use of the fungal pathogen Beauveria bassiana as a nodulation elicitor, with inhibition of phospholipase A2 by dexamethasone, extends the principle to fungi. This study also provides the first evidence of involvement of the lipoxygenase (LOX) pathway rather than the cyclooxygenase (COX) pathway in synthesis of the nodulation mediating eicosanoid(s). The LOX product, 5(S)‐hydroperoxyeicosa‐6E,8Z,11Z,14Z‐tetraenoic acid (5‐HPETE), substantially reversed nodulation inhibition caused by dexamethasone and the LOX inhibitors, caffeic acid and esculetin. The COX product, prostaglandin H2 (PGH2), did not reverse the nodulation inhibition by dexamethasone or the COX inhibitor, ibuprofen. None of the inhibitors tested had a significant effect on the phagocytosis of B. bassiana blastospores in vitro. Hemocyte phenoloxidase activity was reduced by dexamethasone, esculetin, and the COX inhibitor, indomethacin. The rescue candidates 5‐HPETE and PGH2 did not reverse the inhibition. Arch. Insect Biochem. Physiol. 51:46–54, 2002. Published 2002 Wiley‐Liss, Inc.
Tumor necrosis factor α‐mediated joint destruction is inhibited by targeting osteoclasts with osteoprotegerin
Authors: Redlich Kurt , Hayer Silvia , Maier Andrea , Dunstan Colin R. , Tohidast‐Akrad Makiyeh , Lang Susanne , Türk Birgit , Pietschmann Peter , Woloszczuk Wolfgang , Haralambous Silva , Kollias George , Steiner Günter , Smolen Josef S. , Schett Georg 
Published: October 2002

AbstractObjectiveTo study the effects of osteoclast‐targeted therapies, such as osteoprotegerin (OPG) and pamidronate, on joint inflammation and bone destruction using a tumor necrosis factor α (TNFα)‐transgenic mouse model.MethodsMice were placed into 5 groups that received either OPG, pamidronate, a combination of both agents, infliximab as a positive control, or phosphate buffered saline as a negative control. Treatment was initiated at the onset of arthritis, continued over 6 weeks, and thereafter, the clinical, radiologic, and histologic outcomes were assessed.ResultsA significant improvement in clinical symptoms, as assessed by the reduction of paw swelling, was only found in the infliximab group, whereas all other treatment groups failed to show significant improvement. However, when assessing structural damage with radiographic analysis, a significant retardation of joint damage was evident in animals treated with OPG (55% reduction of erosions), pamidronate (50% reduction of erosions) the combination therapy of OPG and pamidronate (64% reduction of erosions), and with infliximab (66% reduction of erosions). Confirming these data, quantitative histologic analysis revealed a significant reduction in the size of bone erosions in all treatment groups (OPG 56%, pamidronate 53%, OPG and pamidronate 81%, and infliximab 46%) compared with the control group. Furthermore, a significant reduction of osteoclast numbers was seen in animals treated with OPG alone or in combination with pamidronate as well as in animals treated with infliximab.ConclusionThese data suggest that OPG alone or in combination with bisphosphonates is an effective therapeutic tool for the prevention of TNFα‐mediated destruction of bone by reducing the number of bone‐resorbing cells in the inflammatory tissue.
Takayasu arteritis: Utility and limitations of magnetic resonance imaging in diagnosis and treatment
Authors: Tso Elisa , Flamm Scott D. , White Richard D. , Schvartzman Paulo R. , Mascha Edward , Hoffman Gary S. 
Published: October 2002

AbstractObjectivePrevious studies have confirmed the poor correlation of symptoms, signs, and levels of acute‐phase reactants with disease activity in ∼50% of all patients with Takayasu arteritis (TA). Invasive angiographic studies demonstrate vessel lumen anatomy, but do not provide qualitative information about the vessel wall. Moreover, sequential invasive angiographic studies expose patients to high‐dose ionizing radiation and catheter/procedure‐related morbidity. The aim of the present study was to determine the utility of new developments in vascular magnetic resonance (MR) technology in patients with TA.MethodsElectrocardiogram‐gated “edema‐weighted” MR was used to evaluate the aorta and its primary branches with regard to the vascular lumen, vessel wall anatomy, and vessel wall edema in 24 TA patients (77 studies). Inclusion criteria were age <50 years and features of TA on both clinical examination and invasive angiographic studies. Patients were stratified based on clinical and laboratory indications of having either unequivocally active disease, inactive disease, or uncertain disease status.ResultsMR revealed vessel wall edema in 94% (17 of 18), 81% (13 of 16), and 56% (24 of 43) of studies obtained during periods of unequivocally active disease, uncertain disease activity, and apparent clinical remission, respectively. Westergren erythrocyte sedimentation rate and C‐reactive protein values did not correlate with either the clinical assessment of disease activity or MR evidence of vascular edema. The frequency of presumed vascular inflammation (edema), as assessed by MR, in patients who appeared to be in remission was similar to the reported frequency of new angiographic lesions and histopathologic evidence of active disease in surgical specimens from patients thought to be in remission. However, the presence of edema within vessel walls did not consistently correlate with the occurrence of new anatomic changes found on subsequent studies.ConclusionInconsistencies in the presence or absence of vessel edema and subsequent anatomic changes have cast doubt on the utility of edema‐weighted MR imaging as a sole guide to disease activity and treatment in TA. In this study, the greatest utility of MR was in providing a safe, noninvasive means of assessing changes in vascular anatomy.
Association of the interleukin‐1 gene cluster on chromosome 2q13 with knee osteoarthritis
Authors: Loughlin John , Dowling Barbara , Mustafa Zehra , Chapman Kay 
Published: October 2002

AbstractObjectiveTo investigate whether the interleukin‐1 (IL‐1) ligand gene cluster at 2q13 encodes for genetic susceptibility to primary osteoarthritis (OA).MethodsSeven single‐nucleotide polymorphisms (SNPs) and a variable‐number tandem repeat (VNTR) polymorphism from within the IL‐1 ligand genes IL1A, IL1B, and IL1RN were genotyped in a cohort of 557 OA cases and 557 age‐matched controls.ResultsNone of the variants demonstrated association in the unstratified data set. However, when cases were stratified according to sex and site of disease (hip or knee), 4 SNPs showed marginal evidence for association (P < 0.1) in knee cases (n = 136) and male knee cases (n = 58). For 2 of these SNPs, evidence for association was enhanced when probands from 60 knee‐only affected sibling pair families were genotyped and combined with the original knee cases (P ≤ 0.05). Further analysis revealed that the associated alleles at 2 of these SNPs were markers for the same haplotype, the frequency of which was significantly elevated when knee cases and knee probands were combined (P = 0.01, odds ratio [OR] 1.4) and when male knee cases and male knee probands were combined (P = 0.009, OR 1.7). Furthermore, linkage analysis of 2q revealed suggestive evidence for linkage to the IL‐1 gene clusters in affected sibling pairs concordant for knee OA but no evidence for linkage in affected sibling pairs concordant for hip OA.ConclusionThe IL‐1 ligand cluster encodes for susceptibility to knee OA but not to hip OA, highlighting the genetic heterogeneity of this common, complex disease.
Small nerve fiber involvement in systemic lupus erythematosus: A controlled study
Authors: Omdal Roald , Mellgren Svein Ivar , Gøransson Lasse , Skjesol Astrid , Lindal Sigurd , Koldingsnes Wenche , Husby Gunnar 
Published: October 2002

AbstractObjectiveTo determine if patients with systemic lupus erythematosus (SLE) may have a peripheral neuropathy involving unmyelinated and small, myelinated nerve fibers, by immunostaining epidermal nerve fibers (ENF) in skin biopsy samples for the panaxonal marker, protein gene product 9.5 (PGP 9.5).MethodsFifteen consecutive and nonselected SLE patients and 15 age‐ and sex‐matched controls were included in the study. The age of the patients ranged from 25 years to 65 years, with a mean ± SD age of 47.3 ± 10.2 years and a disease duration of 2–28 years (mean ± SD 14.8 ± 8.6 years). Two 3‐mm skin biopsy samples were obtained with a punch needle ∼10 cm superior to the lateral malleolus of the right leg and immunostained with 0.1% rabbit polyclonal antibodies to human PGP 9.5. The number of ENF per millimeter was counted and recorded as the mean ± SD of counts in six 50‐μm sections, 3 from each of the 2 biopsy samples.ResultsThe mean number of ENF per mm in patients with SLE was 8.0 ± 1.5 (range 5.0–9.9), while the matched controls had 12.2 ± 3.8 ENF per mm (range 6.8–18.6) (P = 0.0006).ConclusionThis study indicates that a small fiber involvement in patients with SLE may be responsible for the prevalent neuropathic symptoms and impaired warm sense that is observed in such patients.