bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamic vulcanization of acrylic rubber‐blended PVC
Authors: Wong‐On Jessada , Wootthikanokkhan Jatuphorn 
Published: March 2003

AbstractPoly(vinyl chloride) was blended with an acrylic rubber at a variety of blending ratio using a twin‐screw extruder. The acrylic rubber was compounded with sulfur and sodium stearate in a two‐roll mill prior to the blending. Dynamic vulcanization was performed in a compression mould at 170°C. Mechanical properties of the blends were determined by using a tensile testing machine. Scanning electron microscope was used to examine morphology of these blends. Degree of crosslinking of acrylic rubber in the blends was evaluated by using a differential scanning calorimeter. It was found that the normal blends are miscible regardless of the blending variables. By performing dynamic vulcanization, however, the blends became immisicible, showing a typical dispersed particle morphology, which was accompanied by a remarkable improvement of tensile properties. The screw‐rotating speed was an important parameter affecting particle size and crosslink density of the rubber phase, which in turn controlled the tensile toughness of the blends. On the one hand, tensile toughness increased with the speed because of the decreasing particle size. On the other hand, the toughness decreased with the speed because of the decreasing crosslink density of the rubber. As a result, there was an optimum speed for each blend ratio, which corresponded to the maximum toughness. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2657–2663, 2003
Structure and applications of CB/crystal fluoride resin alloy in self‐regulated heating cables
Authors: Wang Jikui , Guo Weihong , Cheng Shujun , Zhang Zhiping 
Published: March 2003

AbstractA conductive composite was prepared by blending carbon black with a modified crystal fluoride resin alloy. The formulation and the processing technology were optimized, and the positive‐temperature‐coefficient (PTC) characteristics under different conditions were studied by SEM, WAXD, and DSC. Relationships between the properties and the structures are illustrated, and applications of this composite in high‐grade temperature self‐regulating heating cables (135°C) are suggested. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2664–2669, 2003
Study of free‐radical copolymerization of N‐isopropylacrylamide with 2‐acrylamido‐2‐methyl‐1‐propanesulphonic acid
Authors: Zhang Chi , Easteal Allan J. 
Published: March 2003

AbstractThe free‐radical copolymerization of N‐isopropylacrylamide and 2‐acrylamido‐2‐methyl‐1‐propanesulphonic acid at varying comonomer mole ratios was studied at 70°C. The extent of conversion was determined as a function of time and comonomer mixture composition, and copolymer compositions were determined using elemental analysis and 13C NMR spectroscopy. Monomer reactivity ratios were evaluated for low conversions using Kelen‐Tüdos and Fineman‐Ross methods. The copolymers were characterized using 13C and 1H NMR spectra, FTIR spectroscopy, and differential scanning calorimetry. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2563–2569, 2003
Preparation and adsorption properties for metal ions of chitin modified by L‐cysteine
Authors: Shao Jian , Yang Yumin , Shi Chuanguo 
Published: March 2003

AbstractA new adsorbent for heavy metal ions, cys‐chitin, was produced by modifying chitin in THF with L‐cysteine in the presence of sulfuric acid as a catalyst. Its structure was confirmed by elemental analysis and FTIR spectra analysis. The adsorption properties of cys‐chitin for CuII, CdII, PbII, ZnII, and NiII were investigated. The effect of pH value on adsorption and adsorption kinetics was examined. The results indicate that the cys‐chitin has much better adsorption for CdII, PbII, and ZnII than chitin itself. The adsorption capacities of cys‐chitin for CdII, PbII, and ZnII were 214.6, 351.5, and 107.0 mg/g, respectively. It also had good adsorption properties for heavy metal ions. The adsorption capacities were also affected by the acidity of medium. The adsorbed CdII, PbII could be eluted by diluted nitric acid. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2575–2579, 2003
Blends of SBS triblock copolymer with poly(2,6‐dimethyl‐1,4‐phenylene oxide)/polystyrene mixture
Authors: Picchioni Francesco , Casentini Emanuele , Passaglia Elisa , Ruggeri Giacomo 
Published: March 2003

AbstractBlends of styrene–butadiene–styrene (SBS) or styrene–ethylene/1‐butene–styrene (SEBS) triblock copolymers with a commercial mixture of polystyrene (PS) and poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) were prepared in the melt at different temperatures according to the chemical kind of the copolymer. Although solution‐cast SBS/PPO and SBS/PS blends were already known in the literature, a general and systematic study of the miscibility of the PS/PPO blend with a styrene‐based triblock copolymer in the melt was still missing. The thermal and mechanical behavior of SBS/(PPO/PS) blends was investigated by means of DSC and dynamic thermomechanical analysis (DMTA). The results were then compared to analogous SEBS/(PPO/PS) blends, for which the presence of a saturated olefinic block allowed processing at higher temperatures (220°C instead of 180°C). All the blends were further characterized by SEM and TGA to tentatively relate the observed properties with the blends' morphology and degradation temperature. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2698–2705, 2003
Optical properties of injection‐molded polystyrene scintillators. II. Distribution of dopants
Authors: Martins J. A. , Seixas J. , Oliveira M. J. , Maio A. , Pouzada A. S. 
Published: March 2003

AbstractThe distribution of fluorescing dye solutes in scintillating tiles for the Tilecal/Atlas project is assessed, and a link between the homogeneity of the dopant distribution and the optical yield and nonuniformity is established. The effect of the injection‐molding parameters on the dye distribution is also analyzed, as well as the actual dye incorporation into the scintillators. This incorporation has been assessed with a set of experiments performed with laboratory samples with controlled amounts of additives and with samples obtained from injection‐molded scintillators. Differential scanning calorimetry has been used to characterize the raw material and to establish a link between the thermophysical properties and the processing conditions, and it is proven to be a quite appropriate technique. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2714–2718, 2003
Low power millimeter wave irradiation exerts no harmful effect on human keratinocytes in vitro
Authors: Szabo Imre , Manning Michael R. , Radzievsky Alexander A. , Wetzel Michele A. , Rogers Thomas J. , Ziskin Marvin C. 
Published: March 2003

AbstractLow power millimeter wave (LP‐MW) irradiation has been successfully used in clinical practice as an independent and/or supplemental therapy in patients with various diseases. It is still not clear, however, whether exposed skin is directly affected by repeated LP‐MW irradiation and whether cells of the epidermis can be activated by the absorbed energy. Keratinocytes, the most numerous component of the epidermis are believed to manifest functional responses to physical stimuli. In this study we analyzed whether LP‐MW irradiation modulated the production of chemokines, including RANTES and IP‐10 of keratinocytes in vitro. We also investigated whether LP‐MW irradiation induces a heat stress reaction in keratinocytes, and stimulates heat shock protein 70 (Hsp70) production. Vital staining of keratinocytes with carboxyfluorescein succinimidyl ester and ethidium bromide was used to analyze the MW effect on the viability of adherent cells. In addition, we studied the effect of LP‐MW irradiation on intercellular gap junctional communication in keratinocyte monolayers by Lucifer yellow dye transfer. We found no significant changes in constitutive RANTES and inducible IP‐10 production following LP‐MW irradiation. LP‐MW exposure of keratinocyte monolayers did not alter Hsp70 production, unlike exposure to higher power MWs (HP‐MW) or hyperthermia (43 °C; 1 h). LP‐MW irradiation and hyperthermia did not alter the viability of adherent keratinocytes, while HP‐MW irradiation induced cellular damage within the beam area. Finally, we found no alteration in the gap junctional intercellular communication of keratinocytes following LP‐MW irradiation, which on the other hand, was significantly increased by hyperthermia. In summary, we detected no harmful effect of LP‐MW irradiation on both keratinocyte function and structure in vitro, although these cells were sensitive to higher MW power that developed heat stress reaction and cellular damage. Our results provide further evidence that LP‐MW irradiation does not induce evidence of skin inflammation or keratinocyte damage and that its clinical application appears to be safe. Bioelectromagnetics 24:165–173, 2003. © 2003 Wiley‐Liss, Inc.
Development of a dielectric equivalent gel for better impedance matching for human skin
Authors: Sunaga Takahiro , Ikehira Hiroo , Furukawa Shigeo , Tamura Mitsuru , Yoshitome Eiji , Obata Takayuki , Shinkai Hiroshi , Tanada Shuji , Murata Hajime , Sasaki Yasuhito 
Published: March 2003

AbstractIt would be useful to develop a tissue equivalent gel to improve the uniformity of the electromagnetic field in the human body, and for making a tissue equivalent dielectric human phantom. In this study, solid type, water based gelatin‐honey gels were developed which have the electrical characteristics of skin tissue. It was demonstrated that a stable and homogeneous gel, with a relative dielectric constant ε′ chosen from desired ranges found in skin, can be made for 200–400 MHz. Bioelectromagnetics 24:214–217, 2003. © 2003 Wiley‐Liss, Inc.
Effects of GSM‐900 microwaves on the experimental allergic encephalomyelitis (EAE) rat model of multiple sclerosis
Authors: Anane R. , Geffard M. , Taxile M. , Bodet D. , Billaudel B. , Dulou P.E. , Veyret B. 
Published: March 2003

AbstractThe effects of acute exposure to GSM‐900 microwaves (900 MHz, 217 Hz pulse modulation) on the clinical parameters of the acute experimental allergic encephalomyelitis (EAE) model in rats were investigated in two independent experiments: rats were either habituated or nonhabituated to the exposure restrainers. EAE was induced with a mixture of myelin basic protein and Mycobacterium tuberculosis. Female Lewis rats were divided into cage control, sham exposed, and two groups exposed either at 1.5 or 6.0 W/kg local specific absorption rate (SAR averaged over the brain) using a loop antenna placed over their heads. There was no effect of a 21 day exposure (2 h/day) on the onset, duration, and termination of the EAE crisis. Bioelectromagnetics 24:211–213, 2003. © 2003 Wiley‐Liss, Inc.
Extremely low frequency magnetic field exposure modulates the diurnal rhythm of the pain threshold in mice
Authors: Choi Yoon Mee , Jeong Ji Hoon , Kim Jeong Soo , Lee Byung‐Cheon , Je Hyun Dong , Sohn Uy Dong 
Published: March 2003

AbstractThe aim of this study was to determine whether exposure to extremely low frequency magnetic field (ELF‐MF) affects the normal diurnal rhythm of the pain threshold in mice. Pain thresholds were evaluated in mice using the hot plate test. A significant increase of pain threshold during night was observed compared to that during day. This rhythm was attenuated by both constant exposure to light (LL) and constant exposure to darkness (DD) for 5 days. Under DD exposure, the diurnal rhythm in pain threshold was restored when mice were exposed to ELF‐MF (60 Hz, 1.5 mT for 12 h daily, from 08:00 to 20:00 h) for 5 days. The diurnal rhythm was not reversed under dark with reversed ELF‐MF cycle (exposure to 1.5 mT from 20:00 to 08:00 h, next day) for 5 days, although pain threshold in the ELF‐MF exposed period of night was slightly decreased. The diurnal rhythm of melatonin analgesic effect related to pain threshold was also observed under DD by the exposure of ELF‐MF for 5 days, but not for 5 nights. The present results suggest that ELF‐MF may participate in the diurnal rhythm of pain threshold by acting on the system that is associated with environmental light‐dark cycle. Bioelectromagnetics 24:206–210, 2003. © 2003 Wiley‐Liss, Inc.
Subjective symptoms among mobile phone users—A consequence of absorption of radiofrequency fields?
Authors: Wilén Jonna , Sandström Monica , Hansson Mild Kjell 
Published: March 2003

AbstractIn a previous epidemiological study, where we studied the prevalence of subjective symptoms among mobile phone (MP) users, we found as an interesting side finding that the prevalence of many of the subjective symptoms increased with increasing calling time and number of calls per day. In this extrapolative study, we have selected 2402 people from the epidemiological study who used any of the four most common GSM MP. We used the information about the prevalence of symptoms, calling time per day, and number of calls per day and combined it with measurements of the Specific Absorption Rate (SAR). We defined three volumes in the head and measured the maximum SAR averaged over a cube of 1 g tissue (SAR1g) in each volume. Two new exposure parameters Specific Absorption per Day (SAD) and Specific Absorption per Call (SAC) have been devised and are obtained as combinations of SAR, calling time per day, and number of calls per day, respectively. The results indicates that SAR values >0.5 W/kg may be an important factor for the prevalence of some of the symptoms, especially in combination with long calling times per day. Bioelectromagnetics 24:152–159, 2003. © 2003 Wiley‐Liss, Inc.
Structures and interactions of the core histone tail domains
Authors: Zheng Chunyang , Hayes Jeffrey J. 
Published: March 2003

AbstractThe core histone tail domains are “master control switches” that help define the structural and functional characteristics of chromatin at many levels. The tails modulate DNA accessibility within the nucleosome, are essential for stable folding of oligonucleosome arrays into condensed chromatin fibers, and are important for fiber–fiber interactions involved in higher order structures. Many nuclear signaling pathways impinge upon the tail domains, resulting in posttranslational modifications that are likely to alter the charge, structure, and/or interactions of the core histone tails or to serve as targets for the binding of ancillary proteins or other enzymatic functions. However, currently we have only a marginal understanding of the molecular details of core histone tail conformations and contacts. Here we review data related to the structures and interactions of the core histone tail domains and how these domains and posttranslational modifications therein may define the structure and function of chromatin. © 2003 Wiley Periodicals, Inc. Biopolymers 68: 539–546, 2003
Quantitative characterization of specific genomic promoters using agarose gel electrophoresis
Authors: Georgel Philippe T. , Hansen Jeffrey C. 
Published: March 2003

AbstractOver the past decade a large number of studies have focused attention on the role of nucleosomes as negative and positive regulators of specific nuclear functions. Due to the lack of an analytical method to determine the higher order conformation of the nucleosomal arrays that encompass specific genetic loci (e.g., promoters, enhancers), research emphasis has mostly been centered on chromatin remodeling and histone posttranslational modifications. We have recently developed an agarose gel electrophoresis method that permits us to analyze the higher order structure of specific in vivo assembled chromatin fragments. After calibration using a well‐defined in vitro system, we have been able to experimentally determine the size, shape, and conformational flexibility of the Mouse Mammary Tumor Virus long‐terminal repeat promoter region in its repressed and activated states. These studies pave the way for widespread analyses of the higher order structure of specific, functionally important chromosomal loci, and in so doing enhance our understanding of the roles that the higher order structure of chromatin play in genome regulations. © 2003 Wiley Periodicals, Inc. Biopolymers 68: 557–562, 2003
Molecular dynamics simulations of A · T‐rich oligomers: Sequence‐specific binding of Na+ in the minor groove of B‐DNA
Authors: Mocci Francesca , Saba Giuseppe 
Published: March 2003

AbstractMolecular dynamics simulations have been employed to probe the sequence‐specific binding of sodium ions to the minor groove of B‐DNA of three A · T‐rich oligomers having identical compositions but different orders of the base pairs: C(AT)4G, CA4T4G, and CT4A4G.Recent experimental investigations, either in crystals or in solution, have shown that monovalent cations bind to DNA in a sequence‐specific mode, preferentially in the narrow minor groove regions of uninterrupted sequences of four or more adenines (A‐tracts), replacing a water molecule of the ordered hydration structure, the hydration spine.Following this evidence, it has been hypothesized that in A‐tracts these events may be responsible for structural peculiarities such as a narrow minor groove and a curvature of the helix axis.The present simulations confirm a sequence specificity of the binding of sodium ions: Na+ intrusions in the first layer of hydration of the minor groove, with long residence times, up to ∼3 ns, are observed only in the minor groove of A‐tracts but not in the alternating sequence. The effects of these intrusions on the structure of DNA depend on the ion coordination: when the ion replaces a water molecule of the spine, the minor groove becomes narrower. Ion intrusions may also disrupt the hydration spine modifying the oligomer structure to a large extent. However, in no case intrusions were observed to locally bend the axis toward the minor groove. The simulations also show that ions may reside for long time periods in the second layer of hydration, particularly in the wider regions of the groove, often leading to an opening of the groove. © 2003 Wiley Periodicals, Inc. Biopolymers 68: 471–485, 2003
1H‐NMR studies on a potent and selective antagonist at human melanocortin receptor 4 (hMC‐4R)
Authors: Victoria Silva Elipe Maria , Mosley Ralph T. , Bednarek Maria A. , Arison Byron H. 
Published: March 2003

AbstractMelanocortin receptor 4 (MC‐4R) is involved in the regulation of energy balance and body weight, and recognizes α‐, β‐, and γ‐melanocyte stimulating hormones (α‐, β‐, γ‐MSH). In the search for compounds that regulate food intake and body weight, two synthetic lactam‐derivative ligands of α‐MSH were discovered, MTII and SHU9119. MTII is an agonist and reduces food intake in rats, whereas SHU9119 is an antagonist, and increases food intake and body weight in rats. MTII and SHU9119 are nonselective compounds to MC‐4R. To enhance the potency and selectivity at the human MC‐4R (hMC‐4R), we recently synthesized analogs of SHU9119 (M. A. Bednarek, T. MacNeil, R. N. Kalyani, R. Tang, Van der L. H. T. Ploeg, and D. H. Weinberg, Journal of Medicinal Chemistry, 2001, Vol. 44, pp. 401–409), wherein compound 1 was the most selective for hMC‐4R. Replacement of D‐Nal by L‐Nal in compound 1 made compound 2 weakly active. Comparison of the structures by NMR and molecular modeling of compounds 1 and 2 vs SHU9119 and MTII indicated that, even though they existed as an average of several conformations in solution, there were distinctions in their structures. The γ‐methylene protons of Arg in compound 1 were nonequivalent and shielded probably by the aromatic ring of Nal. The NHi–NHi+1 NOE cross peaks and the temperature coefficients of the amide protons around the “essential core” Nal/Phe7–Arg8–Trp9, required for high affinity and high selectivity at hMC‐4R, were indicative of a possible turn structure for these compounds but with differences in their NOE strengths and temperature coefficient values. Molecular modeling of these compounds based on their NMR data showed that the essential core appeared as a “V” shape with two different orientations, one for compound 1 and some of the conformers of SHU9119 and MTII, and the other for compound 2 and some other conformers of SHU9119 and MTII. The remaining conformers of SHU9119 and MTII, which did not map to compound 1 or 2, suggested that they were outside of the hMC‐4R binding envelop. These observations may lead to conjectures as to why compound 1 is highly active and selective toward hMC‐4R. © 2003 Wiley Periodicals, Inc. Biopolymers 68: 512–527, 2003
Elongational flow studies on conformational change in DNA induced by DNA‐binding protein HU
Authors: Endoh Takashi , Iyaguchi Daisuke , Sasaki Naoki , Tanaka Isao , Nakata Mitsuo 
Published: March 2003

AbstractInteraction of DNA‐binding protein HU from Bacillus stearothermophilis (HUBst) with coliphage T2 DNA was investigated by observing an elongational flow‐induced birefringence, Δn, of a T2‐phage DNA aqueous solution at various HU concentrations. Localized flow birefringence was observed in the pure elongational flow region, and the strain rate dependence of Δn had a critical strain rate ϵ˙c for the appearance of flow birefringence at all of the HU concentrations examined, indicating that a coil–stretch transition occurred at ϵ˙c in each DNA–HU system. For strain rates larger than ϵ˙c, Δn increased rapidly and then gradually, approaching a plateau value. The value of ϵ˙c increased with an increase in HU concentration. Analysis based on the relationship between ϵ˙ c and the Rouse–Zimm relaxation time revealed that the increase in ϵ˙cwith increase in HU can be explained by the decrease in the size of the DNA–HU complex. The plateau birefringence value, Δnp, decreased at small HU concentrations but did not change at larger HU concentrations. Considering that Δnp is related to the orientational order parameter of segments, it was concluded that there were at least two stages in the process of compaction of DNA induced by HU. © 2003 Wiley Periodicals, Inc. Biopolymers 68: 486–496, 2003
A framework for delivering fine granularity and fair service discrimination in DiffServ networks
Authors: Dumitrescu Avadora , Harju Jarmo 
Published: March 2003

AbstractIn order to achieve a quality of service (QoS) capable of satisfying an ever increasing range of user requirements, differentiated services (DiffServ) have been introduced as a scalable solution that emerges ‘naturally’ from today's best effort service approach. Mapping the packet treatment into a small number of per hop behaviours (PHBs) is the key idea behind the scalability of DiffServ but this comes at the cost of loosing some behavioural differentiation and some fairness between flows multiplexed into the same aggregated traffic. The paper proposes a novel simple and effective DiffServ approach, the ‘Simple Weighted Integration of diFferentiated Traffic’ (SWIFT), and uses it in a series of simulations covering a relatively wide range of local network conditions. Measured voice and video traffic traces and computer generated self‐similar background traffic were used in simulations performed at various congestion levels and for in‐profile and out‐of‐profile source behaviour. The resulted throughput, mean delay, maximum delay and jitter are used to asses SWIFT's capabilities—isolation of the in‐profile traffic from congestion effects, treatment differentiation, increased resource utilization, fairness in treatment under congestion, and incentivity for nice behaviour. Comparisons with other approaches employing traffic control are also provided. Copyright © 2003 John Wiley & Sons, Ltd.