bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of ovarian hormones on human cortical excitability
Authors: Smith Mark J. , Adams Linda F. , Schmidt Peter J. , Rubinow David R. , Wassermann Eric M. 
Published: October 2002

AbstractOvarian steroids appear to alter neuronal function in women, but direct physiological evidence is lacking. In animals, estradiol enhances excitatory neurotransmission. Progesterone‐derived neurosteroids increase GABAergic inhibition. The effect of weak transcranial magnetic stimulation of the motor cortex on the motor evoked potential (MEP) from transcranial magnetic stimulation given milliseconds later is changed by GABAergic and glutamatergic agents. Using this technique previously, we showed more inhibition in the luteal phase relative to the midfollicular menstrual phase, which is consistent with a progesterone effect. To detect the effects of estradiol, we have now divided the follicular phase. We tested 14 healthy women during the early follicular (low estradiol, low progesterone), late follicular (high estradiol, low progesterone), and luteal (high estradiol, high progesterone) phases, with interstimulus intervals from 2 to 10msec (10 trials at each interval and 40 unconditioned trials). We calculated the ratio of the conditioned MEP at each interval to the mean unconditioned MEP: the higher the ratio, the less inhibition and the more facilitation caused by the first stimulus. The combined ratios increased significantly from the early follicular phase to the late follicular phase and then decreased again in the luteal phase. These findings demonstrate an excitatory neuronal effect associated with estradiol and confirm our earlier finding of inhibition associated with progesterone.
Germline mosaicism of a novel mutation in lysosome‐associated membrane protein‐2 deficiency (Danon disease)
Authors: Takahashi Maki , Yamamoto Ayaka , Takano Kyoko , Sudo Akira , Wada Takahito , Goto Yu‐Ichi , Nishino Ichizo , Saitoh Shinji 
Published: October 2002

AbstractWe identified a family with lysosome‐associated membrane protein‐2 deficiency (Danon disease) associated with a novel 883 ins‐T mutation in the lysosome‐associated membrane protein‐2 gene located at Xq24. Although the affected son and daughter carried the same mutation, it was not detected in their mother's peripheral blood or buccal cells; this indicated germline mosaicism. This is the first molecular evidence for germline mosaicism in Danon disease and has important implications for genetic counseling.
Working memory after traumatic brain injury in children
Authors: Levin Harvey S. , Hanten Gerri , Chang Chung‐Chi , Zhang Lifang , Schachar Russell , Ewing‐Cobbs Linda , Max Jeffrey E. 
Published: October 2002

AbstractTo investigate the effects of traumatic brain injury on working memory in children, we administered semantic (letter identity) and phonological (letter rhyme) N‐back tasks to children who were on average 5 years post‐mild (n = 54) or ‐severe (n = 26) traumatic brain injury and 44 typically developing children who were comparable in age. The correct detection of targets and false alarms were measured for each task. Memory load (which varied from 0 to 3 letters back) and age significantly affected the detection of targets and false alarms in both tasks. The severity of traumatic brain injury affected the correct detection of letters on the identity task and false alarms on the rhyme task. Traumatic brain injury severity also interacted with memory load in its effect on false alarms on the rhyme task. Traumatic brain injury results in impaired working memory and diminished inhibition in children. The N‐back working memory task is feasible for administration to brain‐injured children and potentially could be useful for studying brain activation associated with working memory and effects of drug therapy in this group of patients.
Human antibodies against amyloid β peptide: A potential treatment for Alzheimer's disease
Authors: Dodel Richard , Hampel Harald , Depboylu Candan , Lin Suizhen , Gao Feng , Schock Sabine , Jäckel Steffi , Wei Xing , Buerger Katharina , Höft Christine , Hemmer Bernhard , Möller Hans‐Jürgen , Farlow Martin , Oertel Wolfgang H. , Sommer Norbert , Du Yansheng 
Published: October 2002

AbstractNaturally occurring antibodies directed against β‐amyloid (Aβ) were detected in intravenous immunoglobulin preparations. After intravenous immunoglobulin treatment in patients with different neurological diseases, total Aβ and Aβ1‐42 in the cerebrospinal fluid was reduced significantly compared with baseline values. In the serum, total Aβ levels increased after intravenous immunoglobulin treatment, whereas no significant change was observed in Aβ1‐42 levels. Antibodies against Aβ were found to be increased in the serum and cerebrospinal fluid after intravenous immunoglobulin treatment. This study provides evidence that intravenous immunoglobulin or purified Aβ antibodies may modify Aβ and Aβ1‐42 levels, suggesting potential utility as a therapy for Alzheimer disease.
Dyskinesias and grip control in Parkinson's disease are normalized by chronic stimulation of the subthalamic nucleus
Authors: Wenzelburger Roland , Zhang Bao‐Rong , Poepping Meike , Schrader Bettina , Müller Dieter , Kopper Florian , Fietzek Urban , Mehdorn Hubertus M. , Deuschl Günther , Krack Paul 
Published: October 2002

AbstractDeep‐brain stimulation of the subthalamic nucleus appears to reduce levodopa‐induced dyskinesias, but whether this effect is caused by the reduction of the total levodopa ingestion or represents a direct effect on the motor system is unknown. Precision grip force of grasping movements and levodopa‐induced dyskinesias was analyzed in 10 parkinsonian patients before and after 3 months of deep‐brain stimulation of the subthalamic nucleus. Peak grip force was abnormally increased before surgery in the off‐drug state and, particularly, in the on‐drug state (sensitization). This grip force upregulation normalized with chronic deep‐brain stimulation in both conditions (desensitization). Peak‐dose dyskinesias also improved, and off‐dystonia was completely abolished. Mean dosage of dopaminergic drugs was reduced, but force overflow and dyskinesias were equally improved in 2 patients without a reduction. Despite the same single levodopa test dose, force excess and levodopa‐induced dyskinesias were drastically reduced after 3 months of deep‐brain stimulation of the subthalamic nucleus. This indicates that direct effects of deep‐brain stimulation of the subthalamic nucleus on levodopa‐induced dyskinesias are likely to occur. Grip force overflow is a promising parameter to study the desensitizing effect of chronic deep‐brain stimulation on levodopa‐induced dyskinesias.
Preparation of water‐soluble chitosan derivatives and their antibacterial activity
Authors: Xie Wenming , Xu Peixin , Wang Wei , Liu Qing 
Published: October 2002

AbstractCarboxymethyl chitosan sodium (CMCTS) was synthesized by chitosan and chloroacetic acid under an alkali catalyst. Acrylic acid sodium salt and methylacrylic acid sodium salt were grafted onto CMCTS to obtain copolymers with good water solubility. The graft reaction was carried out at 70°C for 2 h, and ammonium persulfate was used as an initiator. The structure changes of chitosan and its derivatives were investigated by the FTIR. The antibacterial activity of chitosan derivatives against Staphylococcus aureus and Escherichia coli were explored by the viable cell counting method. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1357–1361, 2002
Melt strength of linear low‐density polyethylene/low‐density polyethylene blends
Authors: Ho Kam , Kale Larry , Montgomery Scott 
Published: October 2002

AbstractLinear low‐density polyethylenes and low‐density polyethylenes of various compositions were melt‐blended with a batch mixer. The blends were characterized by their melt strengths and other rheological properties. A simple method for measuring melt strength is presented. The melt strength of a blend may vary according to the additive rule or deviate from the additive rule by showing a synergistic or antagonistic effect. This article reports our investigation of the parameters controlling variations of the melt strength of a blend. The reciprocal of the melt strength of a blend correlates well with the reciprocal of the zero‐shear viscosity and the reciprocal of the relaxation time of the melt. An empirical equation relating the maximum increment (or decrement) of the melt strength to the melt indices of the blend components is proposed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1408–1418, 2002
Preparation of soluble poly(amide imide) derivatives with metal salts and phosphorous compounds
Authors: Jeon Jong‐Young 
Published: October 2002

AbstractSoluble poly(amide imide) derivatives were prepared through the direct polycondensation of 1,2,4‐benzenetricarboxylic acid and three diamines—bis[4‐(3‐aminophenoxy)phenyl]sulfone, bis(4‐aminophenyl)‐1,4‐diisopropylbenzene, and 4,4′‐oxydianilne—in the presence of metal salts and phosphorous compounds. Phosphonium salt, which was used as the initiating species and was prepared by the reaction of the metal salts and phosphorous compounds, reacted with 1,2,4‐benzenetricarboxylic acid to form acyloxy phosphonium salt, and then the salt was reacted with a diamine for the preparation of the prepolymers. The prepolymers were converted into the corresponding poly(amide imide)s in a homogeneous solution state at 180°C. The poly(amide imide)s showed good thermal and mechanical properties. Glass‐transition temperatures were observed from 240 to 270°C in differential scanning calorimetry traces. A melting endotherm was not observed for the polymers with differential scanning calorimetry. The initial decomposition occurred around 400°C according to thermogravimetric analysis, and major weight loss was observed from 610 to 680°C. The poly(amide imide)s had comparatively good solubility in aprotic polar solvents at concentrations high enough (∼30%) for the fabrication of various forms. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1399–1407, 2002
Electromagnetic interference shielding effectiveness and mechanical sliding behavior for electroless nickel/phosphorous–poly(tetrafluoroethylene) codeposition on carbon fiber/acrylonitrile–butadiene–styrene composites
Authors: Huang Chi‐Yuan , Mo Wen‐Wei 
Published: October 2002

AbstractPoly(tetrafluoroethylene) (PTFE) powders were mounted on an electroless nickel/phosphorous (Ni/P) film on the surface of a carbon fiber by an electroless codeposition method. This type of carbon fiber filler, denoted FENCF, was then compounded with acrylonitrile–butadiene–styrene (ABS) for use in electromagnetic interference shielding. For the suspension of the PTFE powders, a surfactant was used. Although the adhesion between the electroless Ni/P–PTFE films and the fiber was reduced, the PTFE powders on the surface of FENCF reduced the torque values when compounded into the ABS matrix because of a self‐lubricating effect. The two‐step FENCF composites exhibited particularly significant advantages. The torque values for the two‐step FENCF/ABS composites were about one‐half of those for carbon fiber/ABS composites in compounding processes; in addition, the former had an average mean fiber length almost 2.5 times that of the latter. The multiyield phenomena in stress–strain curves of FENCF/ABS composites implied that the PTFE powders mounted on Ni/P films slid during stress–strain action. The electromagnetic interference shielding effectiveness of FENCF/ABS composites did not decrease significantly even though the PTFE powders formed a discontinuous phase on the electroless Ni/P films. The mechanical properties of FENCF composites were enhanced because of the larger fiber length. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1661–1668, 2002
Infrared spectra of γ‐irradiated poly(acrylic acid)–polyacrylamide complex
Authors: Moharram M. A. , Rabie S. M. , El‐Gendy H. M. 
Published: October 2002

AbstractSamples of polyacrylamide (PAAm), poly(acrylic acid) (PAA), and their complex were γ‐irradiated at different doses, namely 48, 96, and 144 KGy. The examination of the infrared spectra of these samples showed that there are no significant observable changes in their spectral features apart from slight changes in the intensities of the absorption bands. The analysis of the absorbances ratios (A 1700 cm−1/A 1450 cm−1) and (A 1650 cm−1/A 1450 cm−1), denoted as R1 and R2, respectively, showed that these ratios depend on γ‐doses. It was found that in the case of PAA, R1 assumed linear increase with increasing the dose to 96 KGy and then showed marked decrease. For the complex, R1 increased slightly by increasing the dose to 96 KGy and then decreased. For PAAm, although irradiation with 48 KGy increases the values of R2, irradiation with 96 and 144 KGy decreases its value. On the other hand, for the complex, R2 suggested slight decrease on irradiation with 48 KGy followed by continued increases with increasing the dose up to 144 KGy. The increase in R1 and R2 may be due to crosslinking as a result of the formation of free radicals. The decrease in these ratios after irradiation with 96 KGy may be due to degradation. It was concluded that γ‐irradiation has a lower effect on the complex (i.e., the complex has a structure which is different from those of PAA and PAAm). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1619–1623, 2002
Thermal characteristics of IPNs composed of polyallylamine and chitosan
Authors: Kim Seon Jeong , Park Sang Jun , Shin Mi‐Seon , Lee Yong Hee , Kim Nam Gyun , Kim Sun I. 
Published: October 2002

AbstractInterpenetrating polymer network (IPN) hydrogels composed of polyallylamine and chitosan were synthesized by radical polymerization using 2,2‐dimethyl‐2‐ phenylacetophenone (DMPAP) and methylene bisacrylicamide (MBAAm) as initiator and crosslinker, respectively. The IPNs thus obtained were characterized by using Fourier transform infrared (FT‐IR) spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dielectric analysis (DEA). The melting temperatures of IPNs were observed with increasing chitosan content by DSC. DEA was employed to ascertain the glass transition temperature (Tg) of IPNs. From the result of DEA, IPNs exhibited two Tgs indicating the presence of phase separation in the IPN. The thermal decomposition of IPNs was investigated by TGA and appeared at near 270 °C. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1956–1960, 2002
Characterization of biaxially oriented polypropylene films by atomic force microscopy and microthermal analysis
Authors: Abad M. J. , Ares A. , Barral L. , Cano J. , Díez F. J. , López J. , Ramírez C. 
Published: October 2002

AbstractA new method for evaluating the thermal properties of the films and detecting fabrication failures has been provided. Moreover, this article studies the characterization of biaxially oriented polypropylene films (BOPP) using the Microthermal Analizer (μTA 2990). This instrument combines high‐resolution imaging capabilities of the atomic force microscopy (AFM) with physical characterization by thermal analysis. In the first part of the work, topographic images of the film surfaces were obtained by AFM. They showed that the fabrication process and additives to the films caused differences in the sample topography. In the second part, the thermal conductivity images of multilayer films were obtained by thermal analysis mode. The thickness of each layer was determined for several BOPP films, based on the thermal conductivity signal registered by μTA 2990. Finally, it has been proven that this new technique is valid for detection of thermal transitions in polymer samples. Thus, melting points and glass transitions were measured in the samples with thermal probe. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1553–1561, 2002.
The oxidative degradation of styrenic copolymers: A comparison of photoproducts formation under natural and accelerated conditions
Authors: Singh R. P. , Vishwa Prasad A. , Solanky S. S. 
Published: October 2002

AbstractNatural and accelerated weathering of polystyrene and high‐impact polystyrene were carried out in the present investigation. The structural changes in the polymer samples were characterized by using FTIR spectroscopy, tensile strength testing, and SEM spectroscopy. The natural exposure was conducted throughout the year. Rates of photooxidation were determined by measuring the evaluation in hydroxyl and carbonyl regions. The surface deterioration was revealed from SEM micrographs. The drop in tensile strength was also monitored. A correlation between natural and artificial weathering was considered for lifetime prediction in a short exposure time. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1676–1682, 2002
Graft reaction of acrylic acid onto metallocene‐based polyethylene‐octene elastomer
Authors: Wu Chin‐San , Lai Sun‐Mou , Liao Hsin‐Tzu 
Published: October 2002

AbstractIn this study, grafting of acrylic acid (AA) onto metallocene‐based polyethylene‐octene elastomer (POE) was investigated by using benzoyl peroxide as an initiator. Grafted product was characterized by using Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, X‐ray diffraction spectroscopy, and differential scanning calorimetry (DSC). Both the grafting percentage and the gel yield, at equilibrium, were higher for POE containing lower degree of comonomer content. In all cases, the crosslinking reaction was accompanied by the predominant graft reaction due to the competition of POE macroradical and excited AA. From the result of DSC and X‐ray characterizations, it was found that the change of crystallinity is slight when the gel is removed from POE‐g‐AA copolymers. It was also proven that the effect of gel formation on the properties of the copolymer could be neglected because of the low gel yield. So, the graft method proposed in this article can produce low gel yield copolymer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2905–2912, 2002
Poly(L‐lactide). IX. Hydrolysis in acid media
Authors: Tsuji Hideto , Nakahara Kazumasa 
Published: October 2002

AbstractAmorphous and crystallized poly(L‐lactide) (PLLA) films are prepared by quenching and annealing at 140°C for 600 min, respectively, from the melt. Their hydrolysis is investigated at pH 2.0 in HCl and DL‐lactic acid (DLLA) solutions (37°C) for up to 300 days, and the results are compared with those obtained for PLLA films hydrolyzed at pH 7.4 (phosphate‐buffered solution) and pH 12 (NaOH solution). The changes in the weight loss and molecular weight distribution of the PLLA films during hydrolysis in the acid media reveals that their hydrolysis proceeds homogeneously along the film cross section by mainly a bulk erosion mechanism. Moreover, the durability of PLLA films in the acid media is very similar to that in the neutral medium but higher than that in the alkaline medium. The hydrolysis rate constant values (k) of the initially amorphous PLLA0 film evaluated from the changes in the number‐average molecular weight were 3.0 and 2.4 × 10−3 day−1 at pH 2.0 in the HCl and DLLA solutions, respectively. These k values are very similar to 2.6 × 10−3 day−1 at pH 7.4 in the phosphate‐buffered solution. The similar k values and the negligible weight loss after the hydrolysis for 300 days reflect that the hydronium ions and the lactic acid oligomers and monomers have insignificant catalytic effects on the hydrolysis of the PLLA films. Increasing the initial crystallinity of the PLLA film increases the hydrolysis rate in the HCl solution, whereas increasing the initial crystallinity of the PLLA film does not alter the hydrolysis rate in the DLLA solution. The differential scanning calorimetry results show that the crystallization of PLLA chains occurs during the hydrolysis, irrespective of the hydrolysis acid media and the initial crystallinity. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 186–194, 2002
Ultrasonic improvement of the compatibility and rheological behavior of high‐density polyethylene/polystyrene blends
Authors: Chen Guangshun , Guo Shaoyun , Li Huilin 
Published: October 2002

AbstractThe effects of ultrasonic oscillations on the rheological behavior, mechanical properties, and morphology of high‐density polyethylene (HDPE)/polystyrene (PS) blends were studied. The experimental results show that the die pressure and apparent viscosity of HDPE/PS blends are remarkably reduced in the presence of ultrasonic oscillations and that mechanical properties of the blends are improved. The particle size of the dispersed phase in HDPE/PS blends becomes smaller, its distribution becomes narrower, and the interfacial interaction of the blends becomes stronger if the blends are extruded in the presence of ultrasonic oscillations. Ultraviolet spectra and Soxhlet extraction results show the formation of a polyethylene‐PS copolymer during extrusion in the presence of ultrasonic oscillations, which improves the compatibility of HDPE/PS blends. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 23–32, 2002
Surface modification of polymethyl methacrylate intraocular lenses with the mixture of acrylic acid and acrylamide via plasma‐induced graft copolymerization
Authors: Suh Tae Suk , Joo Choun‐Ki , Kim Young Chai , Lee Moo Suk , Lee Hyoung Koo , Choe Bo Young , Chun Heung Jae 
Published: October 2002

AbstractAn approach is presented for the graft copolymerization of acrylic acid (AAc) and acrylamide (AAm) mixture onto the surfaces of polymethyl methacrylate intraocular lenses (PMMA IOLs) treated with an Argon gas plasma, followed by the exposure to the oxygen atmosphere. In this case, peroxides formed by the plasma treatment are likely to be responsible for initiating the graft copolymerization. The amount of peroxides on the surface of PMMA IOLs was determined using 1,1‐diphenyl‐2‐picrylhydrazyl, and the maximum amount was found with the plasma treatment at 30 W for 20 s under 5 mTorr pressure. The surfaces of the grafted PMMA IOLs were characterized using Fourier transform infrared spectroscopy‐attenuated total reflectance (FTIR‐ATR), electron spectroscopy for chemical analysis, and contact angle meter. The FTIR‐ATR spectrum of PMMA‐g‐AAc‐AAm showed the characteristic band of PAAc at 1580 cm−1 together with those of PAAm at 1670 and 1630 cm−1, confirming that the copolymer of AAc and AAm was successfully grafted onto the surfaces of PMMA IOLs. The experimental data of O1s/C1s and N1s/C1s reasonably concurred with the calculated data, a strong indication that the pH value of the reaction medium at 3.77 could produce a graft with an equal molar ratio. Surface tension of the samples increased to 52 dyn/cm due to the graft of the hydrophilic monomers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2361–2366, 2002
Enhancement of processability of cyanate ester resin via copolymerization with epoxy resin
Authors: Liang Guozheng , Zhang Mingxi 
Published: October 2002

AbstractTwo new matrices with enhanced processing characteristics, made from bisphenol A cyanate ester (BCE) and diglycidyl ether of bisphenol A epoxy resin or o‐cresol formaldehyde novolac epoxy resin, were developed. Solubility, differential scanning calorimetry (DSC), gel time, and tack experiments were used to detect the processing characteristics of the two new systems and neat BCE. Results show that the two new systems have enhanced processability compared with neat BCE, especially improved tack and drape properties of prepregs, and faster thermal polymerization rate. In addition, the two new cured systems have more than two times improved impact strength without a great decrease in excellent dielectric properties or thermal and hot–wet resistance of neat BCE resin. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2377–2381, 2002