bluuebunny/crossref_metadata_2025_split huggingface dataset:
Potassium channel antibodies in two patients with reversible limbic encephalitis
Authors: Buckley Camilla , Oger Joel , Clover Linda , Tüzün Erdem , Carpenter Katherine , Jackson Matthew , Vincent Angela 
Published: August 2002

AbstractLimbic encephalitis (LE) is often associated with lung, thymic, or testicular tumours and antibodies to Hu, CV2, or Ma2 (Ta) antigens. In these cases, it generally has a poor prognosis. Here we describe two patients with symptoms of LE, negative for typical paraneoplastic antibodies, in whom antibodies to voltage‐gated potassium channels (VGKC) were detected retrospectively in serial serum samples. Patient 1 had a thymoma recurrence, but in patient 2 no tumour has been detected in the years following presentation. Plasma exchange was effective in reducing VGKC antibody levels, with substantial improvement in mental symptoms in patient 1. In patient 2, the VGKC antibodies fell spontaneously over two years, with almost complete recovery of mental function. Although neither patient had obvious neuromyotonia at presentation, both showed excessive secretions. We suggest that patients with limbic symptoms and excessive secretions should be tested for VGKC antibodies, and, if they are present, prompt and effective immunosuppressive treatment should be considered.
Metabolic changes following subthalamotomy for advanced Parkinson's disease
Authors: Su Philip C. , Ma Yilong , Fukuda Masafumi , Mentis Marc J. , Tseng Ham‐Min , Yen Ruoh‐Fang , Liu Hon‐Man , Moeller J. R. , Eidelberg David 
Published: August 2002

AbstractWe studied 6 advanced‐stage Parkinson's disease patients with [18F] fluorodeoxyglucose/positron emission tomography before and 3 months after unilateral ablation of the subthalamic nucleus performed with microelectrode mapping. Operative changes in glucose metabolism were assessed by comparing baseline and postoperative scans. We also quantified operative changes in the activity of an abnormal Parkinson's disease‐related metabolic network that we had identified in previous [18F] fluorodeoxyglucose/positron emission tomography studies. Following unilateral subthalamic nucleus ablation, a highly significant reduction in glucose utilization was present in the midbrain ipsilateral to the lesion site, most pronounced in the vicinity of the substantia nigra pars reticularis. Significant metabolic reductions were also present in the ipsilateral internal globus pallidus, ventral thalamus, and pons. Operative changes in Parkinson's disease network activity differed significantly for the lesioned and unlesioned hemispheres. In the lesioned hemisphere, network activity declined significantly following surgery, but was unaltered in the contralateral, unlesioned hemisphere. These results suggest that subthalamotomy reduces basal ganglia output through internal globus pallidus/substantia nigra pars reticularis and also influences downstream neural activity in the pons and ventral thalamus. This procedure also reduces the activity of abnormal Parkinson's disease‐related metabolic brain networks, suggesting a widespread modulation of motor circuitry.
Sexual dimorphism and developmental regulation of substantia nigra function
Authors: Velíšková Jana , Moshé Solomon L. 
Published: August 2002

AbstractThe substantia nigra is an important brain nucleus involved in the expression of movement disorders and seizures. The two most common movement disorders affecting the substantia nigra, Parkinson's disease and Tourette syndrome, show gender differences and age‐related onset. To assess the substrates for the gender and age specificity of substantia nigra‐ related disorders, we determined the functional properties of the substantia nigra γ‐aminobutyric acid (GABAA) system along its anterior‐posterior axis, using localized microinfusions of muscimol (a GABAA agonist) and susceptibility to motor seizures in rats. In the substantia nigra, there are sex‐specific differences in the topographic segregation and functionality of GABAA systems. In mature male rats there are two distinct regions mediating opposite effects on seizures; in female rats there is only one region that can affect seizures. In the neonatal period, the presence of circulating testosterone is essential for the development of a substantia nigra region that exerts proconvulsant effects throughout the rat's life, a unique feature of the male substantia nigra. The final maturation of the substantia nigra occurs in the peripubertal period, and is in part regulated by testosterone as well. The recognition of the existence of distinct sex‐ and age‐specific substantia nigra features can be translated into new cures of disorders affecting the substantia nigra.
Swelling behavior and thermal stability of poly(methylmethacrylate) crosslinked by the oxozirconium cluster Zr4O2(methacrylate)12
Authors: Trimmel Gregor , Gross Silvia , Kickelbick Guido , Schubert* Ulrich 
Published: August 2002

AbstractA new isomer of the oxozirconium cluster Zr4O2(methacrylate)12 was obtained by reaction of zirconium butoxide with an excess of methacrylic acid. Contrary to the known isomer, the structure is centrosymmetric with a planar, rhombic Zr4 core. Copolymerization with a 56–207‐fold excess of methylmethacrylate results in cluster‐crosslinked poly(methylmethacrylate) that swells in ethyl acetate but does not dissolve. The solvent uptake during swelling decreases and the thermal stability improves with an increasing portion of the cluster. Copyright­© 2001 John Wiley & Sons, Ltd.
Thermal cross‐linking and pyrolytic conversion of poly(ureamethylvinyl)silazanes to silicon‐based ceramics
Authors: Li Ya‐Li , Kroke Edwin , Riedel Ralf , Fasel Claudia , Gervais Christel , Babonneau Florence 
Published: August 2002

AbstractThe aim of this work was to study the pyrolytic conversion of a novel commercial polysilazane, poly(ureamethylvinyl)silazane (PUMVS; Ceraset™, Allied Signal Composites Inc., USA), into silicon‐based ceramics. The precursor was thermally cross‐linked and pyrolyzed between 200 and 1700 °C under argon or nitrogen atmosphere and the products were investigated by spectroscopic techniques (FTIR and Raman spectroscopy, solid‐state NMR), elemental analysis and simultaneous thermal analysis coupled with mass spectrometry. Upon heating under argon, the starting liquid precursor transformed into an infusible solid polymer at T > 250 °C with a conversion yield of >95 wt%. The cross‐linking solidification occurred predominantly through hydrosilylation or addition reaction involving vinyl groups. Subsequent pyrolysis of the cross‐linked products around 1000 °C in argon yielded amorphous silicon carbonitride ceramics with a composition of SiN0.82C0.86. The overall ceramic yield (with respect to the starting PUMVS) was around 70 wt%, which was found to be independent of the initial cross‐linking step. Solid‐state NMR (29Si and 13C) revealed that the amorphous silicon carbonitrides contain predominately CSiN3 units. There is evidence for the formation of free amorphous carbon between 700 and 800 °C. Graphitic phases were detected by X‐ray diffraction in the samples heated to T > 1000 °C at high heating rates. Upon annealing at T > 1500 °C, the excess carbon reacted completely with the silicon (carbo)nitride to form SiC and nitrogen. The final ceramics contained a large amount of crystalline SiC (∼90 wt%), and were free of excess carbon or silicon. Therefore, PUMVS is an ideal precursor for the formation of high‐quality SiC‐based ceramics. Copyright © 2001 John Wiley & Sons, Ltd.
Spermiotoxicity and embryotoxicity of triphenyltin in the sea urchin Paracentrotus lividus Lmk
Authors: Moschino Vanessa , Marin Maria Gabriella 
Published: August 2002

AbstractThe most important sources of pollution by triphenyltin (TPT) in marine coastal ecosystems are its employment as a fungicide in agriculture and, in association with tributyltin, as a biocide in antifouling paints. In this study, spermiotoxicity and embryotoxicity (from post‐fertilization to pluteus stage) experiments were carried out to clarify better the ecotoxicological effects of TPT during the development of the sea urchin Paracentrotus lividus. Sperm exposed to triphenyltin acetate (TPTA) for 60 min showed a significantly reduced capability to fertilize eggs even at the lowest TPTA concentration of 0.1 µg l−1. In proportion to increasing TPTA concentrations, the percentage of fertilized eggs decreased, falling to 45% at 10 µg l−1, the maximum TPTA concentration tested. In embryotoxicity experiments at 48 h post‐fertilization, the length of the pluteus somatic rods was significantly reduced (P < 0.001) at 1.5 µg l−1 and above. Progressive increases in skeletal anomalies were also detected, which were highly significant (P < 0.001) at 2 µg l−1. Embryonic development was greatly slowed at the highest TPT concentrations: embryos never reached the pluteus stage at 5 µg l−1, and development was blocked at the gastrula stage at 10 µg l−1. As observed in previous experiments using butyltin compounds, embryotoxic effects on both skeletal deposition and blocked development are presumed to be due to interference of TPT with intracellular calcium homeostasis. Sea urchin gametes are more sensitive to TPT than embryos, this condition emphasising the environmental risk due to TPT contamination. Copyright © 2002 John Wiley & Sons, Ltd.
Structure and in vitro antifungal activity of [2,6‐bis(dimethylaminomethyl)phenyl]diphenyltin(IV) compounds
Authors: Růžic̆ka Aleš , Dostál Libor , Jambor Roman , Buchta Vladimír , Brus Jir̆í , Císar̆ová Ivana , Holc̆apek Michal , Holec̆ek Jaroslav 
Published: August 2002

AbstractA set of seven [2,6‐bis(dimethylaminomethyl)phenyl]diphenyltin(IV) ({[(CH3)2NCH2]2(C6H3)}­(C6H5)2Sn+X−) ionic organotin(IV) compounds (X = Br, NO3, CN, SCN, SeCN, BF4 and PF6) has been prepared and characterized by electrospray ionization mass spectrometry, 1H NMR spectroscopy in CDCl3,119Sn NMR in CDCl3 and DMSO‐d6 solution, as well as by 13C and 119Sn CP/MAS NMR spectroscopy and X‐ray diffraction techniques in the solid state. The in vitro antifungal activity of these water‐soluble ionic organotin(IV) compounds was compared with starting compounds and the antifungal drugs currently in clinical use. Copyright © 2002 John Wiley & Sons, Ltd.
D‐Glucuronate complexes of mono‐, di‐ and triorgano tin(IV) compounds: potentiometric and Mössbauer spectroscopic investigations
Authors: Fiore Tiziana , Foti Claudia , Gianguzza Antonio , Orecchio Santino , Pellerito Lorenzo 
Published: August 2002

AbstractComplex species formation of glucuronate with mono‐, di‐ and trimethyltin(IV) cations has been studied potentiometrically in a wide range of ionic strength (0.1 to 1 mol l−1, NaCl medium), at 25 °C. By a suitable complex formation model, according to which all the interactions are considered, the formation constants at infinite dilution have been calculated by using a well‐tested equation for the ionic strength dependence. The following complex species have been found (R = CH3): [RSn(gluc)(OH)]+, [RSn(gluc)(OH)2]0 and [(RSn)2(gluc)(OH)5]0 for the monomethyltin(IV)–glucuronate system; [R2Sn(gluc)]+ and [R2Sn(gluc)(OH)]0 for the dimethyltin(IV)–glucuronate system; and [R3Sn(gluc)]0 for the trimethyltin(IV)–glucuronate system. Mössbauer investigations, carried out in quickly frozen solution, confirmed the species formation and led us to propose their structural configuration. Copyright © 2002 John Wiley & Sons, Ltd.
Microfocus small‐angle X‐ray scattering investigation of the skin–core microstructure of lyocell cellulose fibers
Authors: Moss C. E. , Butler M. F. , Müller M. , Cameron R. E. 
Published: August 2002

AbstractSkin–core microstructures in hydrated lyocell cellulose fibers were investigated using microfocus small‐angle X‐ray scattering (SAXS). Both single fibers and fiber cross sections were observed. In all the fibers studied, a thin skin layer was observed in which the voids were smaller in cross section and better oriented than those in the core. The division between skin and core may not be sharp. A draw ratio of 0.80 gave fibers with voids that were shorter, larger in cross section, and more misoriented than the fibers produced with a draw ratio of 1.68. In contrast, there was little difference in void structure between samples coagulated in water and in 25% amine oxide aqueous solution. The results are explained in the context of the spinodal decomposition, which is thought to occur during coagulation. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2799–2816, 2002; DOI 10.1002/app.10256
Surface crosslinking of high‐density polyethylene beads in a modified plasma reactor
Authors: Kim Jae Woo , Choi Ho Suk 
Published: August 2002

AbstractHigh‐density polyethylene (HDPE) beads were successfully surface‐crosslinked in a modified plasma reactor. The modified plasma reactor treats large amounts of beads, which are uniformly surface‐crosslinked. In this study, effects of the gas pressure, radio‐frequency (RF) power, and the treatment time on the degree of surface crosslinking were systematically investigated. Degree of surface crosslinking was measured by solvent extraction method (boiling xylene method, BXM). The gel content of plasma‐treated HDPE increases from 0.0 to 1.05% within 10 min at 100 mTorr, 200 W. FTIR and DSC analyses show that the crosslinked layer after plasma treatment is limited only at HDPE surface without changing the bulk thermal property of HDPE. Through the analysis of FTIR, it was confirmed that main peaks corresponding to CH2 bands were decreased and two peaks corresponding to CF2 and CF3 were observed after plasma surface modification. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2921–2929, 2002; DOI 10.1002/app.10295
Synthesis and characterization of 4,5‐bis(4‐fluorobenzoyl)‐1‐methylcyclohexene and its polyethers
Authors: Gao Yan , Jian Xigao , Xuan Yingnan , Xu Zhiyong , Lü Qianjiang 
Published: August 2002

AbstractA new difluoride 4,5‐bis(4‐fluorobenzoyl)‐1‐methylcyclohexene (DFKK) has been prepared with fumaryl chloride, fluorobenzene, and 2‐methyl‐1,3‐butadiene as starting materials through two steps of reactions. This DFKK monomer undergoes reaction with 2,2‐(p‐hydroxyphenyl)‐iso‐propane (BPA) in the presence of excess anhydrous potassium carbonate in sulfolane to give a high molecular weight reactive poly(ether ketone ketone) (PEKK) that is very soluble in solvents such as chloroform and N,N‐dimethylformamide at room temperature, has glass transition temperature of 182°C, and is easily cast into flexible and bale ivory film with tensile strength of 64 MPa. The 5% weight loss temperature is 407°C. Ring‐closing reaction of PEKK with hydrazine gives cyclized PEKK (CPEKK) with improved thermal stability and reduced solubility. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1866–1871, 2002; DOI 10.1002/app.10454
Cut‐out filter for ultraviolet radiation from poly(vinyl alcohol)
Authors: Abd El‐Kader K. M. , El‐Lawindy A. Y. M. , Mansour A. F. , Abdel Hamied S. F. 
Published: August 2002

AbstractThe effects of ultraviolet (UV) radiation and thermal annealing on the optical and mechanical properties of polyvinyl alcohol (PVA) were studied. Pure PVA samples were prepared by casting technique. Xenon arc lamp was used to irradiate the sample. The irradiated PVA sample was heated at 150°C for 2 h. The optical and mechanical properties of original, irradiated, and irradiated and then heated samples were measured. The irradiated and then heated sample showed lower transmission in the wavelength range from 190 to 320 nm and the transmission was higher in the visible region than the original and irradiated samples. The stress–strain measurements were performed. Modulus of elasticity of the double‐treated sample was approximately four times higher than that of original sample. The obtained results show the possibility of using this sample as cut‐out filter for UV radiation. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1295–1299, 2002; DOI 10.1002/app.10486
Manufacture of carbon fibers from polyacrylonitrile precursors treated with CoSO4
Authors: Zhang Wang Xi , Wang Yan Zhi 
Published: August 2002

AbstractFree‐radical solution copolymerization of itaconic acid and acrylonitrile was carried out in DMSO using azodiisobutyronitrile as an initiator, changing the feed rate of itaconic acid. The resulting polymerization solution was spun to form polyacrylonitrile (PAN) precursors of carbon fibers. The precursors were treated with a CoSO4 aqueous solution on‐line. The structure and properties of untreated and treated PAN precursors and the resultant carbon fibers were characterized by SEM and TEM, a stabilization process, etc. It is suggested that CoSO4 acts as a catalyst in the formation of a ladder structure and reduces the temperature of cyclization, and the carbon fibers developed from treated PAN fibers showed improvement in the tensile strength and the Young's modulus. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 153–158, 2002
Interaction of different types of cells on physicochemically treated poly(L‐lactide‐co‐glycolide) surfaces
Authors: Khang Gilson , Choee Jong‐Hwa , Rhee John M. , Lee Hai Bang 
Published: August 2002

AbstractTo improve the cell compatibility of poly(L‐lactide‐co‐glycolide) (PLGA; 75/25 molar ratio of lactide to glycolide) surfaces, we experimented with physicochemical treatments. Chemical treatments employed 70% chloric acid, 50% sulfuric acid, and 0.5N sodium hydroxide solutions, and physical methods included corona and plasma treatments. The water contact angle of surface‐treated PLGA decreased from 73 to 50–60°; that is, the hydrophilicity increased because of the introduction of oxygen‐containing functional groups onto the PLGA backbone according to electron spectroscopy for chemical analysis. The physicochemically modified PLGA surfaces were used to investigate the interaction of four different types of cells—hepatoma (Hep G2), osteoblast (MG 63), bovine aortic endothelial (CPAE), and fibroblast (NIH/3T3) cells—in terms of the surface hydrophilicity and hydrophobicity of PLGA. The cells that adhered and grew on the physicochemically modified PLGA surfaces were counted and observed with scanning electron microscopy. The adhesion and growth of Hep G2, MG 63, CPAE, and NIH/3T3 cells on physicochemically treated PLGA surfaces, especially on chloric acid‐treated PLGA surfaces, were more active than on the control. This result seems closely related to the serum protein adsorption on the surface; the serum proteins were also adsorbed more on the hydrophilic surface. Surface hydrophilicity apparently plays an important role in cell adhesion, spreading, and growth on PLGA surfaces. The surface modification technique used in this study may be applicable to tissue engineering for the improvement of tissue compatibility of film‐ and scaffold‐type substrates. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1253–1262, 2002
Studies of glycolysis of poly(ethylene terephthalate) recycled from postconsumer soft‐drink bottles. I. Influences of glycolysis conditions
Authors: Chen Cheng‐Ho , Chen Chuh‐Yean , Lo Yu‐Wen , Mao Ching‐Feng , Liao Wei‐Tung 
Published: August 2002

AbstractThe glycolysis of recycled poly(ethylene terephthalate) flakes by ethylene glycol (EG) is investigated. Bis‐2‐hydroxyethyl terephthalate (BHET) and oligomers are predominately glycolysis products. The influences of glycolysis temperature, glycolysis time, and the amount of catalyst (cobalt acetate) are illustrated. The BHET, dimer, and oligomers are predominately glycolysis products. The optimum glycolysis temperature is found to be 190°C. If a 190°C glycolysis temperature, 1.5‐h glycolysis time, and 0.002 mol glycolysis catalyst (cobalt acetate) are used, the glycolysis conversion is almost 100%. The glycolysis conversion rate increases significantly with the glycolysis temperature, glycolysis time, and the amount of cobalt acetate. Thermal analyses of glycolysis products are examined by differential scanning calorimetry. In addition, the chemical structures of glycolysis products are also determined by a Fourier transform IR spectrophotometer. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 943–948, 2001
An analysis of capillary water behavior in poly‐p‐phenylenebenzobisoxazole fiber
Authors: Kitagawa Tooru , Yabuki Kazuyuki 
Published: August 2002

AbstractThis study concerns with analysis of water inside a poly‐p‐phenylenebenzobisoxazole (PBO) fiber. It is important to analyze the state of water attached to polymer, because it may affect properties of fibers as the increase of drying speed of water from the fiber. To carry out such observation, differential scanning calorimetry and nuclear magnetic resonance spectroscopy were applied. They reveal the large freezing point depression and the state of water inside wet PBO fiber. It shows extraordinary low crystallization temperature. The reason may be that the water is packed into capillary voids whose diameter is around 2–3 nm. Proton NMR analysis also suggests the above result. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1030–1036, 2001
Changes in structure of PA6 during processing
Authors: Jurkowski B. , Olkhov Y. A. , Kelar K. , Olkhova O. M. 
Published: August 2002

AbstractUsing thermomechanical analysis, the molecular weight distribution and relaxation transitions were investigated in commercial PA6 and in this polymer after passage through an extruder with a static mixer. A diblock or triblock amorphous structure and a crystalline portion in the studied PA6 were found. These amorphous structures differ in the glass transition temperatures by 80–180°C. There was a principal difference in the topological and molecular structures of PA6 depending on the processing conditions—number of cycles and shear rates. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2361–2368, 2001
Starlike Nylon 6/polyurethane block copolymers by reaction injection‐molding process (RIM)
Authors: González‐De Los Santos Eduardo A. , López‐Rodríguez Angélica S. , Lozano‐González Ma. Josefina , Soriano‐Corral Florentino 
Published: August 2002

AbstractStarlike block copolymers of Nylon‐6 and polyurethane were synthesized using ε‐caprolactam as a monomer, caprolactam magnesium bromide as a catalyst, and a star prepolymer of polyurethane. These copolymers were compared with the linear block copolymers of Nylon‐6 and polyurethane. Such copolymers were obtained using the reaction injection‐molding process (RIM) of ε‐caprolactam at different contents of polyurethane (5–30 wt %). In increasing the content of the soft phase, in FTIR, a displacement was observed in the band at 1637 cm−1, assigned to the amide I of the Nylon 6, to a higher wavenumber. This suggests a bigger interaction between the urethane group of the polyurethane and the amide group of the Nylon 6. Star block copolymers showed better mechanical properties compared with the linear ones. This behavior is attributed to the higher crystallinity and ramifications present in the materials. The structure and the thermal properties of the copolymers were studied using different techniques such as DSC, WAXS, DMA, and SEM. A decrease in the crystallinity when increasing the soft phase was also observed. Finally, physical tensile, impact, and hardness tests of the copolymers were carried out. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2483–2494, 2001
Design and synthesis of superabsorbent polymers
Authors: Raju M. Padmanabha , Raju K. Mohana 
Published: August 2002

AbstractA series of novel copolymer superabsorbents based on the monomers acrylamide (AM), acrylic acid (AA), acrylonitrile, methacrylic acid, sodium acrylate (SA), and 2‐hydroxyethyl methacrylate (HEMA) were prepared by copolymerization using ammonium persulfate as an initiator and N,N‐methylenebisacrylamide as a crosslinking agent. The experimental results of superabsorbent polymers (SAPs) show that the absorbency in water and NaCl solutions is maximum for AM, SA, HEMA and AM, AA, SA combinations. The copolymers were characterized by IR spectroscopy. The water retention of soil was also enhanced using the above superabsorbents. Use of SAPs for the growth of the croton plant was also investigated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2635–2639, 2001