bluuebunny/crossref_metadata_2025_split huggingface dataset:
Misuse of corticosteroids in some of the drugs dispensed as preparations from alternative systems of medicine in India
Authors: Gupta S. K. , Kaleekal T. , Joshi S. 
Published: September 2002

AbstractScreening for corticosteroids carried out on 120 samples of alternative medicines which were dispensed to patients suffering mainly from asthma, arthritis, etc., showed that 38.32% of them were adulterated with steroids. Most of these samples were submitted for screening by either a medical practitioner or the patients themselves, who suspected effects of steroids from these drugs. The percentage of steroid positivity was determined in ayurvedic drugs, homeopathic drugs, and unknown or other category of drugs. The presence of steroids in these drugs given for different ailments such as asthma, arthritis, and unknown/other ailments was also tabulated. The results show that a high percentage of these samples contained corticosteroids, however, the distribution of positivity amongst groups was not statistically significant. The lack of proper quality control mechanisms to verify ingredients or efficacy of ‘alternative medicines’ has led to the proliferation of the practice of dispensing spurious drugs containing corticosteroids as alternative medicines. This study aims to highlight the existence of ‘quick fix’ remedies dispensed as ‘alternative medicines’ which not only cause extensive adverse health effects to the patients but also bring alternative systems of medicines into disrepute. The deliberate contamination of corticosteroids with alternative systems of medicine by some practitioners is a cause of great concern. Such practices may not only disgrace alternative systems of medicine but may also lead to adverse side‐effects on chronic exposure. Copyright © 2000 John Wiley & Sons, Ltd.
Interactions between poly(acrylamide)–poly(itaconic acid) and cerium(IV)–nitrilotriacetic acid redox pair in the synthesis of acrylamide and itaconic acid homo‐ and copolymers
Authors: Erbil Candan , Uyanık Nurseli 
Published: September 2002

AbstractHomopolymers of itaconic acid (PIA) and its copolymers with acrylamide (P(IA‐AAm) were synthesized using ceric ammonium nitrate (NH4)2Ce(NO3)6 in combination with nitrilotriacetic acid (NTA) as redox initiator, and potassium persulphate at pH 1. The chain structures of the resulting products have been studied by FTIR spectroscopy. It is concluded from a comparison of spectroscopic results with gravimetric and viscometric data that the depressions in the yields and viscosity numbers in the case of Ce(IV)–NTA redox pair result from interactions between the constituents of the redox initiator and IA. Spectra of the insoluble and pale yellow precipitates, which are formed during the first 4 h of the reaction, after addition of Ce(IV) solution to the NTA and NTA–IA homogeneous solutions, also indicate the presence of various oxidation products.Furthermore, it is observed that H‐bonded homopolymer complex obtained from PAAm–PIA blends, prepared from aqueous solutions containing equal unit moles of each polymer, contain both ordered and defective structures.© 2001 Society of Chemical Industry
Modelling of resol resin polymerization with various formaldehyde/phenol molar ratios
Authors: Manfredi Liliana B , Riccardi Carmen C , Osa Orlando de la , Vázquez Analía 
Published: September 2002

AbstractThe kinetics of polymerization of phenol and formaldehyde are modelled to account for the formation of resol resin with various initial formaldehyde/phenol molar ratios. The conversion of phenol and formaldehyde is used to determine the equilibrium constants for phenolate ion and methylene glycol. The relative concentration of each compound is obtained as a function of time. The molecular weight is also determined for each resol resin at the end of the reaction. The evaluation of substituted phenols, hydroxymethylol phenols and methylene bridges was carried out by infrared spectroscopy. The experimental tendencies are in agreement with the results of the model.© 2001 Society of Chemical Industry
Effects of radiation pretreatments on the rubber adsorption power and reinforcing properties of fillers in rubber compounds
Authors: Cataldo Franco 
Published: September 2002

AbstractRadiation damage to fillers such as carbon black, graphite and silica induced by high doses of γ‐radiation or neutrons dramatically increases their ability to adsorb rubber irreversibly. In fact, the ‘bound rubber’, ie the amount of non‐extractable rubber which remains irreversibly linked to the filler matrix, increases dramatically in radiation‐treated fillers. The increased adsorption power of radiation‐damaged fillers has been attributed to the formation of a higher concentration of surface defects in the form of trapped free radicals, fullerene‐like structures and other kinds of defects.The mechanical properties of rubber compounds filled with radiation‐treated carbon blacks show a significant increase in their reinforcing effects, in line with the increased ability to form ‘bound rubber’.© 2001 Society of Chemical Industry
Photovoltaics literature survey (no. 6)
Authors: Keevers Mark J. 
Published: September 2002

AbstractIn order to help keep readers up‐to‐date in the field each issue of Progress in Photovoltaics will contain a list of recently published journal articles most relevant to its aims and scope. This list is drawn primarily from recent issues of IEEE Transactions on Electron Devices, Journal of Applied Physics, Progress in Photovoltaics, Solar Energy and Solar Energy Materials and Solar Cells, with additional journals surveyed if space permits. To assist the reader, the list is separated into broad categories, but please note that these classifications are by no means strict. Also note that inclusion in the list is not an endorsement of a paper's quality. If you have any suggestions please email Mark Keevers at m.keevers@unsw.edu.au Copyright © 2001 John Wiley & Sons, Ltd.
Optimisation of an asymmetric static concentrator: the PEC‐44D
Authors: Zanesco I. , Lorenzo E. 
Published: September 2002

AbstractIn this paper, the optimisation of the PV static concentrator module PEC‐44D for constant demand during the year is presented. The method used is based on simulation of the system performance during 10 years and the set of concentrator parameters that produces the lowest cost of the PV array is determined. We find that the optimised PEC‐44D module can be 38% cheaper than a standard module. Experimental results were obtained for a prototype of the optimised PEC‐44D to validate the theoretical analysis of the behaviour of the concentrator. We conclude that the daily irradiation measured on the cells correlates well with calculated values, and that the operating temperature of the bifacial cells in this static concentrator is slightly lower than that of the monofacial cells in a standard module. Copyright © 2002 John Wiley & Sons, Ltd.
The impurity photovoltaic (IPV) effect in wide‐bandgap semiconductors: an opportunity for very‐high‐efficiency solar cells?
Authors: Beaucarne G. , Brown A. S. , Keevers M. J. , Corkish R. , Green M. A. 
Published: September 2002

AbstractFollowing recent progress in the study of limiting efficiencies of photovoltaic devices with multiple energy levels, we suggest using the impurity photovoltaic (IPV) effect in wide‐bandgap semiconductors as a means to achieve very‐high‐efficiency solar cells. We discuss the requirements for a high‐efficiency IPV device and review some of the material systems that could be used. As a case study, we investigate theoretically β‐SiC IPV solar cells with a model based on a modified Shockley–Read–Hall theory. The high‐efficiency potential is confirmed and the important issues for implementation are presented and discussed. Copyright © 2002 John Wiley &; Sons, Ltd.
Role of grafting in the emulsion polymerization of vinyl acetate with poly(vinyl alcohol) as an emulsifier. I. Effect of the degree of blockiness on the kinetics and mechanism of grafting
Authors: Budhlall B. M. , Sudol E. D. , Dimonie V. L. , Klein A. , El‐Aasser M. S. 
Published: September 2002

AbstractThe role of grafting in particle nucleation during the emulsion polymerization of vinyl acetate with partially hydrolyzed poly(vinyl alcohol) (PVA) as an emulsifier and potassium persulfate as an initiator was investigated. The polymerizations were carried out in batch with a low solids (10%) recipe. An automated reaction calorimeter (Mettler RC1) was used for the direct monitoring of the kinetics of emulsion polymerizations with three medium molecular weight PVAs differing in their degrees of blockiness (Poval 217EE > 217E > 217). Smith–Ewart case 1 kinetics (average number of free radicals per particle < 0.5) were followed in all cases, and no constant rate in interval II was observed. Contrary to what was expected, a nonlinear relationship was observed between the rate of polymerization (Rp) and the number of particles (Np). At Rp max, Np (217E) > Np (217EE) > Np (217), and the final Np was independent of the degree of blockiness of PVA. The particle size distributions were broad (particle diameter = 20–100 nm) and bimodal. On the basis of these data, we concluded that particle nucleation was continuous and was accompanied by extensive limited aggregation during the particle growth stages. The evolution of the amounts of grafted PVA and poly(vinyl acetate) (PVAc) were determined in polymerizations employing the two PVAs differing the most in blockiness (Poval 217EE and 217). The grafted PVAc followed similar profiles, increasing with conversion, particularly near the end of the two reactions. The amounts of grafted PVAc were about the same in the final latexes (37–39%). In contrast, the grafting of PVA was nearly complete by the time monomer droplets had disappeared in each reaction (25% conversion). However, the extent of grafting differed significantly, with the blockier PVA having about one‐third the grafting of the more random PVA (∼10% vs ∼30%). In these low solids recipes, grafting appeared to be primarily a solution event, occurring predominantly in the aqueous phase and not at the particle/water interface, as was previously speculated. The PVAc grafts grew until the molecules became water‐insoluble and precipitated, forming polymer particles. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3633–3654, 2001
Synthesis and characterization of water‐soluble barbiturate‐ and thiobarbiturate‐functionalized polystyrene
Authors: Raja S. , Dhamodharan R. 
Published: September 2002

AbstractThe synthesis and characterization of barbiturate‐ and thiobarbiturate‐functionalized polystyrene from polystyrene homopolymer by polymer‐modification reactions is discussed. Polystyrene homopolymer quantitatively functionalized at the para postion with diethyl oxomalonate functionality was subjected to a condensation reaction with urea and thiourea in the presence of sodium methoxide in methanol. This reaction proceeded essentially to quantitative conversion to the barbiturate‐ (BAPS) and thiobarbiturate‐functionalized polystyrenes (TBAPS) as estimated by 1H NMR, UV, and IR spectroscopies. Thus, several copolymers of styrene with barbiturate‐ and thiobarbiturate‐functionalized styrene were synthesized. The detailed characterizations of quantitatively functionalized polystyrene using gel permeation chromatographic, IR, UV, and 1H NMR spectroscopic techniques as well as thermogravimetric analysis are discussed. An application of the newly synthesized polymer in removing Cu(II) ions from aqueous solution is demonstrated. This is the first report on the synthesis of BAPS and TBAPS by the polymer‐modification route or otherwise. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 731–737, 2002; DOI 10.1002/pola.10154
Poly(3,4‐ethylenedioxythiophene)‐based copolymers for biosensor applications
Authors: Kros Alexander , Nolte Roeland J. M. , Sommerdijk Nico A. J. M. 
Published: September 2002

AbstractThe synthesis of 3,4‐ethylenedioxythiophene (EDOT) derivatives bearing functional groups is described. Their electrochemical characteristics were investigated with cyclic voltammetry and ultraviolet–visible spectroscopy. Various copolymers of EDOT and modified EDOT containing hydroxyl groups were electrochemically prepared. The ability to bind proteins to the surface of these copolymers was investigated through the covalent coupling of glucose oxidase. The obtained materials were used as working electrodes and were shown to be able to amperometrically detect glucose under aerobic and anaerobic conditions. Possible applications of these materials as biosensors are discussed. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 738–747, 2002; DOI 10.1002/pola.10159
Modeling of photobleaching for the photoinitiation of thick polymerization systems
Authors: Miller G. A. , Gou L. , Narayanan V. , Scranton A. B. 
Published: September 2002

AbstractWe present a mathematical description of the spatial and temporal evolution of the light intensity gradient, initiator concentration gradient, and initiation rate profiles for photobleaching initiator systems. This article builds on the foundation provided by previous researchers' contributions by generalizing the governing differential equations to include the effects of absorption by the initiator fragments, absorption by the monomer, and diffusion of the initiator. Simulation results have confirmed that, at any given time, the initiation rate profile resembles a wave front that propagates through the sample. The simulation results suggest that there is an optimum initiator concentration for efficient photopolymerization of thick samples. As either the initiator concentration or molar absorptivity is increased, the initiation rate at the peak of the wave front increases, the breadth of the propagating front decreases, and the rate of spatial propagation through the sample decreases. In contrast, the maximum photoinitiation rate and rate of spatial propagation of the initiation front can be simultaneously increased with an increasing initiator quantum yield or a decreasing absorptivity of the monomer or photolysis products. Finally, on the basis of these studies, diffusion is expected to have negligible effects in most photobleaching systems. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 793–808, 2002; DOI 10.1002/pola.10162
Synthesis and reaction of β‐hydroxyaspartic acid‐based polymethacrylate
Authors: Sanda Fumio , Yokoi Makiko , Kudo Hiroto , Endo Takeshi 
Published: September 2002

AbstractO‐Methacryloyl‐N‐(tert‐butoxycarbonyl)‐β‐hydroxyaspartic acid dimethyl ester was synthesized by methyl esterification of β‐hydroxyaspartic acid, followed by protection of the amino group with the tert‐butoxycarbonyl group and then the reaction of the hydroxyl group with methacryloyl chloride. The monomer efficiently underwent radical polymerization to afford the corresponding polymer with a number‐average molecular weight of 42,000 in good yields. The alkaline hydrolysis of the polymer occurred not only at the methyl ester but also at the ester moiety between the main and side chains of the polymer. The methyl ester‐free polymer gradually released β‐hydroxyaspartic acid moiety in a phosphate buffer solution with pH = 7.3 and 7.8. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2782–2788, 2002
Homopolymerizations and random copolymerizations of olefins with amino‐substituted cyclopentadienylchromium complexes
Authors: Ogata Keiji , Nakayama Yuushou , Yasuda Hajime 
Published: September 2002

Abstract1‐(2‐N,N‐Dimethylaminoethyl)‐2,3,4,5‐tetramethylcyclopentadienyl‐chromium dichloride (1), (2‐N,N‐dimethylaminoethyl)cyclopentadienylchromium dichloride (6), and (2‐N,N‐dimethylaminoethyl)indenylchromium dichloride (7) in the presence of modified methylaluminoxane exhibit high catalytic activities for the polymerization of ethylene with random copolymerizations of ethylene with propylene, ethylene with 1‐hexene, and propylene with 1‐hexene. These initiators conduct polymerizations to give high molecular weight polymers with low polydispersities. However, the stereoregularities are very poor in these reactions. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2759–2771, 2002
Emulsion polymerization of styrene using polystyrene‐block‐poly(ethylene oxide) macromonomers as stabilizers
Authors: Gibanel Sébastien , Heroguez Valérie , Forcada Jacqueline 
Published: September 2002

AbstractNew diblock macromonomers were used as reactive emulsifiers in the emulsion polymerization of styrene. The nature of the reactive group, the molecular weight, the length of the poly(ethylene oxide) (PEO) block, and the molecular structure of the macromonomer were systematically investigated during this process by analyzing the evolution of the conversion and particle diameters. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2819–2827, 2002
Structure and morphology of the aliphatic polyester poly(δ‐valerolactone) in solution‐grown, chain‐folded lamellar crystals
Authors: Furuhashi Yukiko , Sikorski Pawel , Atkins Edward , Iwata Tadahisa , Doi Yoshiharu 
Published: September 2002

AbstractPoly(δ‐valerolactone) (PVL) crystals in the form of chain‐folded lamellae were prepared by isothermal crystallization from a 2‐methylbutane‐2‐ol solution. Wide‐angle and small‐angle X‐ray diffraction data, obtained from PVL lamellae sedimented to form oriented mats, were supplemented with morphological and structural data from electron microscopy, both imaging and diffraction. The diffraction signals index on an orthorhombic unit cell with the parameters a = 0.747 ± 0.002 nm, b = 0.502 ± 0.002 nm, and c (chain axis) = 0.742 ± 0.002 nm. Similar unit cell parameters were obtained from crystals grown from 1‐octanol and also from drawn melt‐pressed films. The evidence supports a model containing two antiparallel chain segments in the unit cell. The c value of 0.742 nm is appropriate for an all‐trans or onefold helical backbone conformation for the straight stems. Possible slight perturbations at the ester units from the all‐trans backbone conformation are discussed. Computerized modeling was used to optimize the adjacent‐reentry folded structure. The setting angles, with respect to the a axis, are ±58° for the corner and center chains. The lamellae are 7.26 ± 0.05 nm thick, and the chains run orthogonal to the lamellar surface. The chains fold in the diagonal (110) and (11¯0) planes in an alternating fashion. The X‐ray diffraction data suggest that a proportion of adjacent paired antiparallel entities, or hairpin units, are c‐axis‐sheared, and a relationship to the results obtained from drawn films is discussed. A brief comparison is also made with related polymer structures. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2622–2634, 2001
Free‐energy model of asymmetry in side‐chain liquid‐crystalline diblock copolymers
Authors: Anthamatten Mitchell , Hammond Paula T. 
Published: September 2002

AbstractSide‐chain liquid‐crystalline‐b‐amorphous copolymers combine the thermotropic ordering of liquid crystals (LCs) with the physics of block copolymer phase segregation. In our earlier experiments, we observed that block copolymer order–order and order–disorder transitions could be induced by LC transitions. Here we report the development of a free‐energy model to understand the interplay between LC ordering and block copolymer morphology in an incompressible melt. The model considers the interaction between LC moieties, the stretching of amorphous chains from curved interfaces, interfacial surface contributions, and elastic deformation of the nematic phase. The LC block is modeled with Wang and Warner's theory, in which nematogens interact through mean‐field potentials, and the LC backbone is modeled as a wormlike chain. Free energy is estimated for various morphologies: homogeneous, lamellar, cylinder micelle, and spherical micelle. Phase diagrams were constructed by iteration over temperature and composition ranges. The resulting composition diagrams are highly asymmetric, and a variety of first‐order transitions are predicted to occur at the LC clearing temperature. Qualitatively, nematic deformation energies destabilize curved morphologies, especially when the LC block is in the center of the block copolymer micelle. The thermodynamics of diblocks with laterally attached, side‐on mesogens are also explored. Discussion focuses on how well the model captures experimental phenomena and how the predicted phase boundaries are affected by changes in polymer architecture. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2671–2691, 2001
From structure to function: YrbI from Haemophilus influenzae (HI1679) is a phosphatase
Authors: Parsons James F. , Lim Kap , Tempczyk Aleksandra , Krajewski Wojiech , Eisenstein Edward , Herzberg Osnat 
Published: September 2002

AbstractThe crystal structure of the YrbI protein from Haemophilus influenzae (HI1679) was determined at a 1.67‐Å resolution. The function of the protein had not been assigned previously, and it is annotated as hypothetical in sequence databases. The protein exhibits the α/β‐hydrolase fold (also termed the Rossmann fold) and resembles most closely the fold of the L‐2‐haloacid dehalogenase (HAD) superfamily. Following this observation, a detailed sequence analysis revealed remote homology to two members of the HAD superfamily, the P‐domain of Ca2+ ATPase and phosphoserine phosphatase. The 19‐kDa chains of HI1679 form a tetramer both in solution and in the crystalline form. The four monomers are arranged in a ring such that four β‐hairpin loops, each inserted after the first β‐strand of the core α/β‐fold, form an eight‐stranded barrel at the center of the assembly. Four active sites are located at the subunit interfaces. Each active site is occupied by a cobalt ion, a metal used for crystallization. The cobalt is octahedrally coordinated to two aspartate side‐chains, a backbone oxygen, and three solvent molecules, indicating that the physiological metal may be magnesium. HI1679 hydrolyzes a number of phosphates, including 6‐phosphogluconate and phosphotyrosine, suggesting that it functions as a phosphatase in vivo. The physiological substrate is yet to be identified; however the location of the gene on the yrb operon suggests involvement in sugar metabolism. Proteins 2002;46:393–404. © 2002 Wiley‐Liss, Inc.
Structure of bovine α‐1,3‐galactosyltransferase and its complexes with UDP and DPGal inferred from molecular modeling
Authors: Rao Mohan , Tvaroska Igor 
Published: September 2002

AbstractA homology model of α‐1,3‐galactosyltransferase (α‐1,3‐GalT), the retaining enzyme responsible for the formation of α‐galactosyl epitopes, has been developed by means of molecular modeling using the SpsA glycosyltransferase structure. A protein‐ligand docking approach was used to model α‐1,3‐GalT complexed with UDP and UDP‐Gal. The comparison of structural features found in the α‐1,3‐GalT homology model with available structural data on this class of enzymes revealed similarities in the UDP‐binding pocket. In the predicted structure of the complexes, the pyrophosphate interacts with the DVD motif (Asp‐225, Val‐226, and Asp‐227) of α‐1,3‐GalT through the Mn2+ cation. The uridine part of the UDP binds into the well‐defined cavity that consists of Phe‐134, Tyr‐139, Ile‐140, Val‐136, Arg‐194, Arg‐202, Lys‐209, Asp‐173, His‐218, and Thr‐137 in a conformation that is generally observed in the crystal structures of other glycosyltransferase complexes. Proteins 2001;44:428–434. © 2001 Wiley‐Liss, Inc.