bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reentrant phase transition of poly(N‐isopropylacrylamide) gels in polymer solutions: Thermodynamic analysis
Authors: Gündogan Nermin , Okay Oguz 
Published: August 2002

AbstractThe swelling behavior of poly(N‐isopropylacrylamide) (PNIPA) gels in polymer solutions, particularly in aqueous solutions of poly(ethylene glycol)s, was investigated using the theory of equilibrium swelling. The volume of the PNIPA gel and the partition parameter of the macromolecules between the gel and the solution phases were calculated for various extents of the energetic interactions between the components. The simulation results were compared with the experimental data reported in the literature. It was shown that the PNIPA gel has a tendency to a reentrant phase transition in an aqueous solution of low molecular weight linear polymers. In such a transition, the gel first collapses, then reswells, if the linear polymer concentration is continuously varied. The necessary condition for the reentrant behavior of PNIPA gels was predicted in terms of the interaction parameters among the PNIPA network, the linear polymer, and water. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 801– 813, 2002
Role and relevance of polarity and hindrance of vinyl monomers in graft copolymerization onto potato starch
Authors: Fu Zheng Sheng , Liang Wei Dong , Yang Ai Mei , Wang Zhi Guo 
Published: August 2002

AbstractThe graft copolymerization of the vinyl monomers that were prepared by reactions of methyl acrylate and 4‐aminoazobenzene derivatives, such as 4‐aminoazobenzene, 4‐amino‐4′‐methyl azobenzene, 4‐amino‐4′‐nitro azobenzene, and 4‐amino‐3′,5′‐dinitro azobenzene, onto potato starch were carried out by the initiation of potassium persulfate. The evidence of grafted copolymers was investigated by using FTIR spectroscopy and acid hydrolysis technique. The relationship between grafting efficiency and monomer structure as well as polarity was studied. The experimental results showed that the graft copolymerization is independent of the polarity of the vinyl monomers and that the structures of monomers exhibit a marked influence on the graft copolymerization, namely, the larger the substitute is, the lower the grafting efficiency will be. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 896–899, 2002
Correlation between migration behaviors of antiozonants and temperature
Authors: Choi Sung‐Seen 
Published: August 2002

AbstractMigration behaviors of antiozonants depending on temperature were studied using a carbon black‐filled NR vulcanizate containing N‐phenyl‐N′‐isopropyl‐p‐phenylenediamine (IPPD) and N‐phenyl‐N′‐(1,3‐dimethylbutyl)‐p‐phenylenediamine (HPPD) as antiozonants. The experimental temperatures were 100, 90, 80, and 70°C. Migration rates of them increased steeply by increasing the temperature. The correlation between the migration rates and the temperature was investigated using the half (t1/2)‐ and quarter (t1/4)‐lifetimes of the migrants remaining in the vulcanizate after the migration. The plot of log t versus 1/T was well fitted by the linear equation: The correlation coefficients were higher than 0.995. It was found that the migration behavior and temperature had a correlation of log t = b/T + c, where t and T are the migration time and temperature, b is Ea/R, and c is the constant. The activation energies for the migration were 36.48 and 37.93 kJ/mol for IPPD and HPPD, respectively. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1566–1570, 2001
Photoimaging technique on printing Al plate via self‐assembly multilayer films based on diazoresin
Authors: Chen Jinyu , Luo Hao , Yang Boxuan , Cao Weixiao 
Published: August 2002

AbstractA photoimaging technique on a printing aluminum plate (anodized oxidation Al plate) via self‐assembly multilayer thin film from nitro‐containing diazoresin (NDR) as cationic polyelectrolyte and various anionic polyelectrolytes has been developed. It was confirmed that, under UV‐irradiation, the linkage nature of the films changes from ionic to covalent and the solubility of the films converts dramatically, that is, the exposed area of the film becomes insoluble in H2O–DMF–LiCl (2 : 4 : 1 wt %) ternary solvent, but mainly the unexposed area will be dissolved. After developing in ternary solvent, an image that accepts ink easily appears on the printing Al plate. To resolve the ink‐stain problem, originating from a trace remainder of the NDR on the unexposed area of the Al plate, a surface modification technique by polyphosphoric acid, which reacts with NDR to form a hydrophilic surface, was developed. The thickness, homogeneity, and surface morphology of the multilayer film (on mica) determined by atomic force microscopy and UV‐vis spectra were also reported. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1983–1987, 2001
Nitroxide‐mediated homopolymerization and copolymerization of 2‐vinylpyridine with styrene
Authors: Lokaj J. , Holler P. 
Published: August 2002

AbstractHomopolymerization and copolymerization of 2‐vinylpyridine (2VP) with styrene (S) at 125°C in the presence of 2,2,6,6‐tetramethyl piperidin‐1‐yloxyl (TEMPO) radicals have been studied. The homopolymerization was carried out with 2,2′‐azobis(isobutyronitrile) (AIBN) as a thermal initiator or without AIBN in the initial reaction mixture. In the copolymerization initiated with AIBN, the molar fraction of 2VP in the feed, F2VP, varied in the range of 0.1–0.9; F2VP = 0.65 was found to be the azeotropic composition. The linear semilogarithmic time–conversion plots demonstrated a pseudoliving nature of the polymerizations under study. The molecular weight–conversion dependences indicated the participation of side reactions, diminishing the number of TEMPO‐terminated polymer chains. The synthesized homopolymers and copolymers were characterized using size‐exclusion chromatography (SEC), nitrogen analysis, and NMR spectroscopy. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2024–2030, 2001
Toughness enhancement of poly(ethylene terephthalate) with functionalized ultrahigh molecular weight polyethylene
Authors: Mascia L. , Ophir A. 
Published: August 2002

AbstractUltrahigh molecular weight polyethylene (UHMWPE) is available commercially in the form of powder, consisting of fine primary particles, 1–5 μm in diameter, agglomerated into secondary “free‐flowing” particles with overall dimensions in the region of 50 to 150 μm. These are normally sufficiently coherent and retain their conglomerated particulate structure when blended with other polymers because of the extremely high viscosity of UHMWPE. In this study the surface of the agglomerated primary particles was acid functionalized by reactions with aqueous solutions of acrylic acid, after being irradiated with γ‐radiation at 15–45 kGy. The acid groups were used to introduce a glycidoxyl functionality through reactions with a difunctional cycloaliphatic epoxy resin and also to a “partial” metal carboxylate functionality through reactions with zinc acetyl acetonate. When blended with polyethylene terephthalate (PET) in either a small‐batch mixer or in a twin‐screw extruder all the treated powders, except those functionalized with acrylic acid, were broken down to their primary size and were uniformly dispersed and strongly bonded to the surrounding matrix. The blends containing the deglomerated particles were found to have much greater ductility and toughness than those produced from both untreated and acid functionalized powder. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2972–2986, 2001
Study of carbon black distribution in BR/NBR blends based on damping properties: Influences of carbon black particle size, filler, and rubber polarity
Authors: Sirisinha Chakrit , Prayoonchatphan Nootjaree 
Published: August 2002

AbstractEffects of filler and rubber polarity on the distribution of filler in butadiene/nitrile rubber (BR/NBR) blends were investigated, using the dynamic mechanical thermal analysis technique. As 30‐phr filler is added, the reduction in heights of damping peaks (tan δmax), attributed to the dilution effect, was observed. It was also found that the BR phase in the blends, compared to the NBR phase, is more preferential for small‐ and large‐particle size carbon blacks to reside, probably because of the lower viscosity and lower polarity of the BR phase. The addition of silica instead of carbon black leads to an increase in filler migration to the NBR in the 20/80 BR/NBR blend, which is attributed to the strong silica–NBR interaction. In addition, an increase in NBR polarity promotes carbon black migration to the BR phase. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3198–3203, 2001
Preparation and characterization of some new unsaturated polyesters based on 3,6‐bis(methoxymethyl)durene
Authors: Tawfik S. Y. 
Published: August 2002

AbstractA series of unsaturated polyester resins based on 3,6‐bis(methoxymethyl)durene with different diacids or anhydrides, namely, phthalic anhydride, maleic anhydride, and succinic acid, and different glycols, namely, 1,2‐propylene glycol, triethylene glycol, 1,4‐cyclohexane diol, and 3,6‐bis(benzyloxymethyl)durene, were prepared. Infrared and nuclear magnetic resonance spectra were used to characterize the unsaturated polyester resins obtained qualitatively and quantitatively. The average‐number molecular weight (M−n) was determined by end‐group analysis. These polyesters were found to cure with styrene at room temperature. The thermal behavior of the styrenated polyesters was studied via thermogravimetrical analysis and differential scanning calorimetry (TGA and DSC). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3388–3398, 2001
Medical neurobiology: Do we teach neurobiology in a format that is relevant to the clinical setting?
Authors: Haines Duane E. , Hutchins James B. , Lynch James C. 
Published: August 2002

AbstractDuring a period of unprecedented growth in technology that allows imaging of the body in elegant detail, anatomy as a discipline has, in some instances, become marginalized. This may be seen in a reduction of time allotted to anatomy, reduction or elimination of laboratory experiences, or shifting of anatomy teaching to clinical departments. One potential cause of this marginalization is the fact that anatomy is frequently taught in a format that is not useful in, or even applicable to, the clinical setting. At the University of Mississippi Medical Center, the Medical Neurobiology course stresses the functional anatomy of the brain, especially the brainstem, in a format that is directly transferable to the clinical setting. These approaches include (1) using a small neurology book as one of the required texts in the course; (2) extensive use of magnetic resonance imaging (MRI) and computed tomography (CT) as an integral part of the instructional approach; (3) teaching external and internal anatomy of the brain, particularly the brainstem and spinal cord, in a “clinical orientation” that reflects how these central nervous system (CNS) regions are viewed in the clinical setting; (4) teaching nuclei and tracts in images of stained sections and correlating this information with comparable MRI and CT images; and (5) using a large series (75 images) of vascular drawings and clinical cases, all in clinical orientation. The clinical applicability of the basic science information, therefore, is continuously reinforced and extended. It is suggested that teaching anatomy and anatomical concepts in formats that are more obviously useful in, and applicable to, the clinical setting will enhance the value of this basic science in the medical curriculum. Anat Rec (New Anat) 269:99–106, 2002. © 2002 Wiley‐Liss, Inc.
Effects of brefeldin‐A: Potent inhibitor of intracellular protein transport on ultrastructure and resorptive function of cultured osteoclasts
Authors: Sahara Takako , Sasaki Takahisa 
Published: August 2002

AbstractBrefeldin‐A (BFA) is a specific and potent inhibitor of the intracellular transport of clathlin‐uncoated transitional vesicles from the cisterns of rough‐surfaced endoplasmic reticulum (RER) to the Golgi lamellae. This study was designed to clarify the effects of BFA on ultrastructure, subcellular localization of vacuolar‐type H+‐ATPase and a lysosomal cysteine proteinase, cathepsin K, in cultured osteoclasts and their resorptive function. H+‐ATPase and cathepsin K are the most important enzymes for decalcification of apatite crystals and degradation of type‐I collagen, respectively. In control cultures without BFA, osteoclasts were structurally characterized by the development of broad ruffled borders and clear zones, and formed many resorption lacunae in cocultured dentine slices. In BFA‐treated cultures, osteoclasts lacked ruffled borders, and the cytoplasm was filled with regular‐size and extremely large pale vacuoles over 2 μm in diameter, which were produced by fusion of adjacent vacuoles. BFA did not, however, inhibit clear zone formation and adhesion of osteoclasts to dentine slices. Resorption lacuna formation was markedly diminished by BFA treatment. Although H+‐ATPase and cathepsin K were strongly expressed in osteoclast ruffled borders in control cultures, BFA treatment altered the subcellular localization and decreased the expression of these molecules. In BFA‐treated cultures, H+‐ATPase immunoreaction in osteoclasts was observed along the limiting membranes of some, but not all, regular‐size pale vacuoles, but neither in extremely large vacuoles nor along the smooth plasma membranes facing the dentine slices. Similarly, cathepsin K was localized within lysosomes and some regular‐size pale vacuoles, but its secretion toward the dentine slices through the ruffled borders was strongly inhibited by BFA treatment. These results suggest that 1.) formation of the osteoclast ruffled borders and their resorptive function are closely associated with the intracellular transport of these molecules from the RER cisterns and the Golgi lamellae to the ruffled borders, and 2.) both H+‐ATPase and cathepsin K are selectively transported to the ruffled border membranes by pale vacuoles. Anat Rec 263:127–138, 2001. © 2001 Wiley‐Liss, Inc.
Comparative and functional anatomy of the mammalian lumbar spine
Authors: Boszczyk Bronek M. , Boszczyk Alexandra A. , Putz Reinhard 
Published: August 2002

AbstractAs an essential organ of both weight bearing and locomotion, the spine is subject to the conflict of providing maximal stability while maintaining crucial mobility, in addition to maintaining the integrity of the neural structures. Comparative morphological adaptation of the lumbar spine of mammals, especially in respect to locomotion, has however received only limited scientific attention. Specialised features of the human lumbar spine, have therefore not been adequately highlighted through comparative anatomy. Mathematical averages were determined of 14 measurements taken on each lumbar vertebrae of ten mammalian species (human, chimpanzee, orang‐utan, kangaroo, dolphin, seal, Przewalski's horse, cheetah, lama, ibex). The revealed traits are analysed with respect to the differing spinal loading patterns. All examined mammalian lumbar spines suggest an exact accommodation to specific biomechanical demands. The lumbar spine has reacted to flexion in a predominant plane with narrowing of the vertebral bodies in quadrupeds. Torsion of the lumbar spine is withstood by an increase in the transverse distance between the inferior articular processes in the upper lumbar spine in primates, but lower lumbar spine in humans, quadrupeds and the seal. Sagittal zygapophyseal joint areas resist torsion in the seal and humans. Ventral shear is resisted by frontal zygapophyseal joint areas in humans and primates, and dorsal shear by encompassing joints in the ibex. The human fifth lumbar vertebra is remarkable in possessing the largest endplate surface area and the widest distance between the inferior articular processes, as an indicator of the high degree of axial load and torsion in bipedalism. Anat Rec 264:157–168, 2001. © 2001 Wiley‐Liss, Inc.
Prostaglandin biosynthesis by fat body from larvae of the beetle Zophobas atratus
Authors: Tunaz Hasan , Putnam Sean M. , Stanley David W. 
Published: August 2002

AbstractWe describe prostaglandin (PG) biosynthesis by microsomal‐enriched fractions of fat body prepared from larvae of the tenebrionid beetle, Zophobas atratus. PG biosynthesis was sensitive to incubation time, temperature, pH, substrate and protein concentration. Optimal PG biosynthesis conditions of those we examined included 2 mg of microsomal‐enriched protein, incubated at 22°C for 2 min at pH 6. These preparations yielded four major PGs: PGA2, PGE2, PGD2 and PGF2α. PGA2 and PGF2α were the predominant eicosanoids produced under these conditions. Two non‐steroidal anti‐inflammatory drugs, indomethacin and naproxen, effectively inhibited PG biosynthesis in low concentrations. In vitro PG biosynthetic reaction conditions, using vertebrate or invertebrate enzyme sources, usually include a cocktail of reaction co‐factors. The Z. atratus preparation similarly performs better in the presence of co‐factors. Arch. Insect Biochem. Physiol. 49:80–93, 2002. © 2002 Wiley‐Liss, Inc.
Insect G protein‐coupled receptors and signal transduction
Authors: Broeck Jozef Vanden 
Published: August 2002

AbstractG protein‐coupled receptors (GPCRs) are seven‐transmembrane proteins (7‐TM) that transduce extracellular signals into cellular physiological responses through the activation of heterotrimeric guanine nucleotide binding proteins (αβγ subunits). Their general properties are remarkably well conserved during evolution. Despite this general resemblance, a large variety of different signals are mediated via this category of receptors. Several GPCR‐(sub)families have an ancient origin that is situated before the divergence of Protostomian and Deuterostomian animals. Nevertheless, an enormous diversification has occurred since then. The availability of novel sequence information is growing very rapidly as a result of molecular cloning experiments and of metazoan genome (Caenorhabditis elegans, Drosophila melanogaster, Homo sapiens) and EST (expressed sequence tags) sequencing projects. The Drosophila Genome Sequencing Project will certainly have an important impact on insect signal transduction and receptor research. In parallel, convenient expression systems and functional assay procedures will be needed to investigate insect receptor properties and to monitor the effects of natural and artificial ligands. The study of the evolutionary aspects of G protein–coupled receptors and of their signaling pathways will probably reveal insect‐specific features. More insight into these features may result in novel methods and practical applications. Arch. Insect Biochem. Physiol. 48:1–12, 2001. © 2001 Wiley‐Liss, Inc.
Recollections of Irving H. Sher 1924–1996: Polymath/information scientist extraordinaire
Authors: Garfield Eugene 
Published: August 2002

AbstractOver a 35‐year period, Irving H. Sher played a critical role in the development and implementation of the Science Citation Index® and other ISI® products. Trained as a biochemist, statistician, and linguist, Sher brought a unique combination of talents to ISI as Director of Quality Control and Director of Research and Development. His talents as a teacher and mentor evoked loyalty. He was a particularly inventive but self‐taught programmer. In addition to the SCI,® Social Sciences Citation Index,® and Arts and Humanities Citation Index,® Sher was involved with the development of the first commercial SDI system, the Automatic Subject Citation Alert, now called Research Alert,® and Request‐A‐Print Cards. Together we developed the journal impact factor and the Journal Citation Reports.® Sher was also the inventor of the SYSTABAR System of coding references and Sherhand. He was involved in key reports on citation‐based historiography, forecasting Nobel prizes, and served as a referee for JASIS over a 20‐year period.
Incentive regulation and the change in productive efficiency in telecommunications in the United States
Authors: Uri Noel D. 
Published: August 2002

AbstractIncentive regulation has become an important regulatory tool in the telecommunications industry in the United States. The issue explored here is whether incentive regulation has resulted in an increase in productive efficiency. After providing an overview of the nature of incentive regulation, a methodology for measuring technical inefficiency and its change is introduced. This is a stochastic frontier production function approach reflecting technical inefficiency effects. The results of implementing this methodology suggest that in the production of interLATA billed access minutes for interstate calls, there was no change in technical efficiency, something that incentive regulation was specifically designed to enhance. Finally, an assessment of technical efficiency across individual LECs in the United States indicates considerable variability. Published in 2001 by John Wiley & Sons, Ltd.
Estimation of absorption rate of α‐human atrial natriuretic peptide from the plasma profile and diuretic effect after intranasal administration to rats
Authors: Miyamoto Misao , Tsukune Tadashi , Hori Seiichi , Hayashi Teruaki , Natsume Hideshi , Sugibayashi Kenji , Morimoto Yasuori 
Published: August 2002

AbstractThe absorption rate of α‐human atrial natriuretic peptide (α‐hANP) after intranasal (i.n.) administration to rats was estimated from the plasma profile and pharmacological effect (diuretic effect) using a pharmacokinetic (PK) model and a PK–pharmacodynamic (PD) model involving data obtained after intravenous (i.v.) bolus injection. The plasma concentrations of α‐hANP after i.v. administration at different doses were fitted to a two‐compartment PK model with zero‐order excretion and input of endogenous α‐rat atrial natriuretic peptide (α‐rANP) and two elimination processes represented by Michaelis–Menten and first‐order kinetics. However, the saturable process was ignored at low doses. The plasma concentrations after low doses via the i.n. route could also be expressed by this model, but with first‐order absorption, so that an absorption rate constant was calculated using a deconvolution method. In addition, the diuretic effect plotted against the i.v. dose was represented by the Hill equation and showed an anti‐clockwise hysteresis loop versus the plasma concentration. These results suggest that the diuretic effect could be estimated by a PK–PD model having an ‘effect’ compartment or a homeostatic system. Such a PK–PD model accurately expressed the diuretic effect of α‐hANP at all doses after i.v. and i.n. administrations. The resulting absorption rate constant calculated using the PK–PD model agreed closely with that obtained by the PK model alone. The absorption rate and simulated diuretic effect suggest that, for i.n. administration of α‐hANP, a higher absorption rate constant causes a more potent diuretic effect (a dramatic effect over the early period), whereas greater bioavailability is associated with a better hypotensive effect (sustained effect). Copyright © 2001 John Wiley & Sons, Ltd.
Use of affinity capillary electrophoresis for characterizing pharmaceutical colloidal vehicle systems thermodynamically
Authors: Reinhard Neubert , Mrestani Yahya 
Published: August 2002

AbstractThis review offers a detailed discussion of the interaction between pharmaceutical compounds and vehicles using the affinity capillary electrophoresis and the microemulsion electrokinetic chromatography. Partition coefficients of drugs were calculated between a micelle and an aqueous phases from the measurement of the migration time, provided the critical micelle concentration and the phase ratio are known. Thermodynamic quantities such as enthalpy and entropy changes of micellar solubilization were calculated from the temperature dependence of the partition coefficients. Partial specific volumes were measured using dynamic light scattering. The logarithm of the partition coefficients and the capacity factor in the micellar system were correlated with the logarithm of the n‐octanol/water partition coefficients. Copyright © 2001 John Wiley & Sons, Ltd.