bluuebunny/crossref_metadata_2025_split huggingface dataset:
Body image dissatisfaction and distortion, steroid use, and sex differences in college age bodybuilders
Authors: Peters Mark Anthony , Phelps LeAddelle 
Published: August 2002

AbstractCollege age bodybuilders were compared by sex (female, male) and steroid intake (nonuse, use) on two variables: body image dissatisfaction and body image distortion. Results of 2 × 2 ANOVAs (sex by steroid use) revealed only a significant effect for gender on body distortion. No steroid‐use differences were apparent for either body image dissatisfaction or body image distortion. Further analyses indicated that female bodybuilders were equally split between desiring more muscle bulk versus a thinner frame, whereas the majority of male bodybuilders wanted to build more muscle mass. These results are compared to previous research with non‐bodybuilders wherein body image dissatisfaction was unidirectional for females (i.e., all desired slimness) yet bidirectional for males (i.e., some aspired to increased muscle mass whereas others sought a reduction in body fat). © 2001 John Wiley & Sons, Inc.
Dual differentiation: An approach for meeting the curricular needs of gifted students with learning disabilities
Authors: Baum Susan M. , Cooper Carolyn R. , Neu Terry W. 
Published: August 2002

AbstractGifted students who experience difficulty with reading, mathematics, spelling, handwriting, and organization frequently become frustrated at an early age. Well‐intentioned teachers attempt to remediate their weaknesses; yet, these youngsters still feel alone in the classroom. Moreover, their academic limitations often mask enormous talent, which seldom has an opportunity to surface. Thus, gifted learning‐disabled students require curriculum that develops their special talents and provides them strategies to compensate for problematic weaknesses. This article discusses the dual characteristics of gifted learning‐disabled students and suggests a unique curriculum that integrates both through talent development. Developed through Project HIGH HOPES, funded federally by the Javits Act (1993–1996), this dually differentiated curriculum offers strategies for addressing students' learning problems while fulfilling their need for sophisticated challenge through advanced‐level content and a focus on solving authentic, real‐world problems. © 2001 John Wiley & Sons, Inc.
Concurrent SN1 and SN2 reactions in the benzylation of pyridines
Authors: Yoh Soo‐Dong , Cheong Duk‐Young , Lee Chung‐Heun , Kim Sung‐Hong , Park Jong‐Hwan , Fujio Mizue , Tsuno Yuho 
Published: August 2002

AbstractThe Menschutkin reactions of 3,4‐methylenedioxybenzyl and 3,4‐dimethoxybenzyl bromides and also p‐methoxybenzyl bromide with Y‐substituted pyridines were kinetically studied for a range of amine concentration in acetonitrile. The strongly activated benzyl bromides showed a significant positive intercept in the plot of the pseudo‐first‐order rate constants against the concentrations of nucleophiles, while less activated benzyl bromides did not give such significant intercepts. The rate data for respective substrates were fitted to the equation kobs = k1 + k2[Nu]. The first‐order rate constant, k1, is unaffected by the nature of the nucleophile, whereas the second‐order rate constant, k2, increased with increasing nucleophilicity. This was ascribed to the simultaneous occurrence of SN1 and SN2 reactions without an intermediate mechanism. These results are taken as evidence for the duality of SN1 and SN2 mechanisms in the Menschutkin reaction in the non‐solvolyzing solvent acetonitrile. Copyright © 2001 John Wiley & Sons, Ltd.
Kinetics and mechanism of methanolysis and cyclization of 1‐acyl‐3‐(2‐halo‐5‐nitrophenyl)thioureas
Authors: Sedlák Miloš , Hanusek Jiří , Holčapek Michal , Štěrba Vojeslav 
Published: August 2002

AbstractThe kinetics of methoxide ion‐catalysed solvolysis of 1‐acyl‐3‐(2‐halo‐5‐nitrophenyl)thioureas and cyclization of fluoro derivatives were studied in methanol at 25 °C. The cyclization involved the substitution of fluorine by sulphur anion of thiourea and proceeded in two steps. With the acetyl derivative, the first step is methanolysis and the second step is much slower cyclization of the 2‐fluoro‐5‐nitrophenylthiourea anion formed to give 2‐amino‐5‐nitro‐1,3‐benzothiazole. With the benzoyl derivative, the first step involves parallel methanolysis of the benzoyl group and cyclization to 2‐benzoylamino‐5‐nitro‐1,3‐benzothiazole. At concentrations of sodium methoxide higher than ca 0.01 mol l−1 the rates of solvolyses of all the acyl halothioureas decreased and at concentrations higher than ca 0.4 mol l−1 there was an increase in the formation of other product(s) than the product of cyclization. After the addition of 18‐crown‐6, the side products were not formed and the cyclizations of fluoro derivatives were considerably accelerated. The slowing of the solvolytic reaction and acceleration of the cyclization reaction are most probably due to the formation of dianions. Copyright © 2001 John Wiley & Sons, Ltd.
A vibrational spectroscopic study of clathrates of resorcarene‐based cavitands
Authors: Dormann Jörg , Ruoff Andreas , Schatz Jürgen , Middel Oskar , Verboom Willem , Reinhoudt David N. 
Published: August 2002

AbstractBy comparison of the fully assigned vibrational spectra obtained for resorcarene‐based cavitands 2a and 2b, their clathrates with toluene and ethanol respectively, and free guest molecules, good structural models for the clathrates could be obtained merely based on Fourier transform infrared data. Using this novel technique, various different interactions between the host and guest in the solid state as well as the orientation of the included guest could be identified. In the case of cavitand 2a, the model obtained by this methodology could be validated by comparison with an experimental crystal structure analysis. Copyright © 2001 John Wiley & Sons, Ltd.
Pulsed‐laser polymerization‐gel permeation chromatographic determination of the propagation‐rate coefficient for the methyl acrylate dimer: A sterically hindered monomer
Authors: Tanaka Kenta , Yamada Bunichiro , Fellows Christopher M. , Gilbert Robert G. , Davis Thomas P. , Yee Lachlan H. , Smith Gregory B. , Rees Mark T. L. , Russell Gregory T. 
Published: August 2002

AbstractThe methyl acrylate dimer (MAD) is a sterically hindered macromonomer, and the propagating radical can fragment to an unsaturated end group. The propagation‐rate coefficient (kp) for MAD was obtained by pulsed‐laser polymerization (PLP). The Mark–Houwink–Sakaruda parameters required for the analysis of the molecular weight distributions (MWDs) were obtained by multiple‐detector gel permeation chromatography (GPC) with on‐line viscometry. The small radical created by the fragmentation results in a short‐chain polymer that means the MWD may no longer be given by that expected for “ideal” PLP conditions; simulations suggest that the degree of polymerization required for “ideal” PLP conditions can be obtained from the primary point of inflection provided the GPC traces also show a clear secondary inflection point (radicals terminated by the second, rather than the first, pulse subsequent to initiation). Over the temperature range of 40–75 °C, the data can be best fitted by kp/dm3 mol−1 s−1 = 106.1 exp(−29.5 kJ mol−1), with a moderately large joint confidence interval for the Arrhenius parameters. The data are consistent with an increased activation energy and reduced frequency factor as compared with acrylate or methacrylate; both of these changes can be ascribed to hindrance. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3902–3915, 2001
Copolymerization of propylene with higher α‐olefins in the presence of the syndiospecific catalyst i‐Pr(Cp)(9‐Flu)ZrCl2/MAO
Authors: Graef Sven M. , Wahner Udo M. , Van Reenen Albert J. , Brüll Robert , Sanderson Ronald D. , Pasch Harald 
Published: August 2002

AbstractThe catalyst system i‐Pr(Cp)(9‐Flu)ZrCl2/methylaluminoxane was used for the synthesis of random syndiotactic copolymers of propylene with 1‐hexene, 1‐dodecene, and 1‐octadecene as comonomers. An investigation of the microstructure by 13C NMR spectroscopy revealed that the stereoregularity of the copolymers decreased because of an increase in skipped insertions in the presence of the higher 1‐olefin. The melting temperature of the copolymers, as measured by differential scanning calorimetry (DSC), decreased linearly with increasing comonomer content independently of the comonomer nature. During the DSC heating cycle, an exothermic peak indicating a crystallization process was observed. The decrease in the crystallization temperature with higher 1‐olefin content, measured by crystallization analysis fractionation, indicated a small but significant dependence on the nature of the comonomer. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 128–140, 2002
Microstructure analysis and thermal property of copolymers made of glycolide and ϵ‐caprolactone by stannous octoate
Authors: Pack Ji Won , Kim Soo Hyun , Cho I‐Whan , Park Soo Young , Kim Young Ha 
Published: August 2002

AbstractGlycolide (GL) and ϵ‐caprolactone (CL) were copolymerized in bulk at relatively high temperatures using stannous octoate as a catalyst. To investigate the relationship among microstructure, thermal properties, and crystallinity, three series of copolymers prepared at various reaction temperatures, times, and comonomer feed ratios were prepared and characterized by 1H and 13C NMR, DSC, and wide‐angle X‐ray diffraction (WAXD). The 600‐MHz 1H NMR spectra provided information about not only the copolymer compositions but also about the chain microstructure. The reactivity ratios (rG and rC) were calculated from the monomer sequences and were 6.84 and 0.13, respectively. In terms of overall feed compositions, the sequence lengths of the glycolyl units calculated from the reactivity ratios exceeded those measured from the polymeric products. Mechanistic considerations based on reactivity ratios, monomer consumption data, and average sequence lengths are discussed. The unusual phase diagram of GL/CL copolymers implies that the copolymer melting temperature does not depend on its composition alone but rather on the nature of the sequence distribution. The DSC and WAXD measurements show a close relationship between polymer crystallinity and the nature of the polymer sequence. © 2002 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 544–554, 2002; DOI 10.1002/pola.10123
Epoxy resins from novel monomers with a bis‐(9,10‐dihydro‐9‐oxa‐10‐oxide‐10‐phosphaphenanthrene‐10‐yl‐) substituent
Authors: Liu Ying Ling 
Published: August 2002

AbstractA new diepoxide and a new diamine, both bearing bis‐(9,10‐dihydro‐9‐oxa‐10‐oxide‐10‐phosphaphenanthrene‐10‐yl‐)‐substituted methylene linkages, were prepared through the reaction of 9,10‐dihydro‐oxa‐10‐phosphaphenanthrene‐10‐oxide with benzophenone derivatives via a simple addition reaction followed by a dehydration reaction. These two compounds were used as monomers for preparing cured epoxy resins with high phosphorus contents. The resultant epoxy resins showed high glass‐transition temperatures (between 131 and 196 °C). All of the cured epoxy resins exhibited high thermal stability, with 5% weight loss temperatures over 316 °C, and excellent flame retardancy, with limited oxygen index values of 37–50. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 359–368, 2002
Synthesis and properties of aromatic poly(ester amide)s with pendant phosphorus groups
Authors: Liou Guey‐Sheng , Hsiao Sheng‐Huei 
Published: August 2002

AbstractTwo series of phosphorus‐containing aromatic poly(ester amide)s with inherent viscosities of 0.46–3.20 dL/g were prepared by low‐temperature solution polycondensation from 1,4‐bis(3‐aminobenzoyloxy)‐2‐(6‐oxido‐6H‐dibenz〈c,e〉〈1,2〉oxaphosphorin‐6‐yl)naphthalene and 1,4‐bis(4‐aminobenzoyloxy)‐2‐(6‐oxido‐6H‐dibenz〈c,e〉〈1,2〉oxaphosphorin‐6‐yl)naphthalene with various aromatic diacid chlorides. All the poly(ester amide)s were amorphous and readily soluble in many organic solvents, such as N,N‐dimethylformamide, N,N‐dimethylacetamide (DMAc), and N‐methyl‐2‐pyrrolidone (NMP). Transparent, tough, and flexible films of these polymers were cast from DMAc and NMP solutions. Their casting films had tensile strengths of 71–214 MPa, elongations to break of 5–10%, and initial moduli of 2.3–6.0 GPa. These poly(ester amide)s had glass‐transition temperatures of 209–239 °C (m‐series) and 222–267 °C (p‐series). The degradation temperatures at 10% weight loss in nitrogen for these polymers ranged from 462 to 489 °C, and the char yields at 800 °C were 55–63%. Most of the poly(ester amide)s also showed a high char yield of 35–45%, even at 800 °C under a flow of air. The limited oxygen indices of these poly(ester amide)s were 35–46. © 2002 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 459–470, 2002; DOI 10.1002/pola.10129
Solid polymer electrolytes. IV. Preparation and characterization of novel crosslinked epoxy‐siloxane polymer complexes as polymer electrolytes
Authors: Liang Wuu‐Jyh , Kuo Chao‐Ling , Lin Chia‐Liang , Kuo Ping‐Lin 
Published: August 2002

AbstractTwo series of novel crosslinked siloxane‐based polymers and their complexes with lithium perchlorate (LiClO4) were prepared and characterized by Fourier transform infrared spectroscopy, solid‐state NMR (13C, 29Si, and 7Li nuclei), and differential scanning calorimetry. Their thermal stability and ionic conductivity of these complexes were also investigated by thermogravimetric and AC impedance measurements. In these polymer networks, poly(propylene oxide) chains with different molecular weights were introduced through self‐synthesized epoxy‐siloxane precursors cured with two curing agents. The glass‐transition temperature (Tg) of these copolymers is dependent on the length of the ether units. The dissolution of LiClO4 considerably increases the Tg of the polyether segments. The dependence of the ionic conductivity was investigated as a function of temperature, LiClO4 concentration, and the molecular weight of the polyether segments. The ion‐transport behavior was affected by the combination of the ionic mobility and number of carrier ions. The 7Li solid‐state NMR line shapes of these polymer complexes suggest a significant interaction between Li+ ions and the polymer matrix, and temperature‐ and LiClO4 concentration‐dependent chemical shifts are correlated with ionic conductivity. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1226–1235, 2002
Facile synthesis of high molecular weight aromatic polyformals containing phthalazinone moiety
Authors: Meng Y. Z. , Tjong S. C. , Wang S. J. , Hay A. S. 
Published: August 2002

AbstractHigh molecular weight aromatic polyformals containing phthalazinone moiety were simply synthesized with a high‐intensity mixing methodology without the presence of phase‐transfer catalyst. Aromatic polyformals can readily be afforded in a very short time and at temperatures ranging from 50 to 140 °C. These polyformals showed high glass‐transition temperatures together with superior thermal properties when compared with a 4,4′‐isopropylidenediphenol (BPA)‐type polyformal and polycarbonate. The glass‐transition temperatures of these aromatic polyformals ranged from 94 to 229 °C. The molecular weights of the polyformals were examined by gel permeation chromatographic technology, and the result showed that the cyclic formation during the condensation could be dramatically reduced at elevated temperature. The molecular weights and solubility increased with an increasing content of bisphenol A in the polyformals. The result demonstrated that the aromatic polyformal with 50% phthalazinone moiety showed the comparable thermal properties with commercial BPA polycarbonate. This method promisingly opened an effective approach to synthesize aromatic polyformals with high molecular weight and without cyclic formations. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1441–1448, 2002
Phenothiazine photosensitizers for onium salt photoinitiated cationic polymerization
Authors: Gomurashvili Zaza , Crivello James V. 
Published: August 2002

AbstractPhenothiazine compounds bearing a wide range of different substituents are excellent photosensitizers for onium salt cationic photoinitiators. These photosensitizers are generally operative in the mid‐ and long‐range regions of the UV spectrum and are especially useful for enhancing the rate of photoinitiated cationic polymerization carried out utilizing both filtered and broadband UV emission sources. In this article, the syntheses of several different substituted phenothiazines are described and the ability of these compounds to photosensitize the photolysis of different onium salt photoinitiators is evaluated. Attempts were made to correlate the structure and spectral characteristics of the phenothiazines with their efficiency of photosensitization in the cationic photopolymerizations of several typical epoxide and vinyl ether monomers. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1187–1197, 2001
A study on acrylamide polymerization by anodic contact glow‐discharge electrolysis: A novel tool
Authors: Sengupta Susanta K. , Sandhir Urvashi , Misra Nira 
Published: August 2002

AbstractContact glow‐discharge electrolysis (CGDE) is an unconventional electrolytic phenomenon in which a plasma is sustained by a direct current (dc) glow‐discharge between an electrode and the liquid electrolyte around it. A remarkable feature of CGDE is highly nonfaradaic chemical effects at the glow‐discharge electrode. During anodic CGDE of an aqueous electrolyte, non‐Faradaic yields originate mainly from reactions triggered by H• and OH• radicals generated in high local concentrations near the anodic plasma/liquid electrolyte interface during the process. The radical‐generating potentiality of anodic CGDE was explored for the polymerization of acrylamide in aqueous media. The percentage of monomer conversion, rate of polymerization, charge efficiency, and viscometric average molar mass of the polymers produced were measured as functions of the quantities of electricity passed. The charge efficiency of the polymerization of acrylamide by anodic CGDE was at least 1 order of magnitude higher than that of ordinary electrochemically initiated polymerization. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1584–1588, 2001
Thermal stability of brominated poly(isobutylene‐co‐isoprene)
Authors: Parent J. Scott , Thom Darren J. , White Greg , Whitney Ralph A. , Hopkins William 
Published: August 2002

AbstractThe thermal stability of brominated isobutylene–isoprene rubber (BIIR) was investigated through studies of the elastomer and a model compound that accurately represented the reactive functionality within the polymer. An analysis of commercial BIIR and reaction products of brominated 2,2,4,8,8‐pentamethyl‐4‐nonene (BPMN) by NMR demonstrated that bromination of isobutylene–isoprene rubber by 1,3‐dibromo‐5,5‐dimethylhydantoin yielded a kinetically favored exomethylene substitution product, 3‐bromo‐6,6‐dimethyl‐2‐(2,2‐dimethylpropyl)‐1‐heptene (2), as opposed to the more stable endo‐isomer, (E,Z)‐4‐(bromomethyl)‐2,2,8,8‐tetramethyl‐4‐nonene (3). The exposure of BIIR and the brominated model compound BPMN to vulcanization temperatures led to the isomerization of 2 to 3 at a rate strongly dependent on HBr concentration. The elimination of HBr from these allylic bromides to produce exo‐ and endo‐conjugated dienes proceeded concurrently with isomerization, and the kinetics of these processes could be rationalized on the basis of a polar reaction mechanism. The product distributions obtained from both the model system and BIIR were consistent, thereby justifying an extension of the model compound approach to an analysis of BIIR vulcanization chemistry. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2019–2026, 2001
Preparation and properties of polybenzoxazine/poly(imide‐siloxane) alloys: In situ ring‐opening polymerization of benzoxazine in the presence of soluble poly(imide‐siloxane)s
Authors: Takeichi Tsutomu , Agag Tarek , Zeidam Rachib 
Published: August 2002

AbstractBenzoxazine monomer (Ba) was blended with soluble poly(imide‐siloxane)s in various weight ratios. The soluble poly(imide‐siloxane)s with and without pendent phenolic groups were prepared from the reaction of 2,2′‐bis(3,4‐dicarboxylphenyl)hexafluoropropane dianhydride with α,ω‐bis(aminopropyl)dimethylsiloxane oligomer (PDMS; molecular weight = 5000) and 3,3′‐dihydroxybenzidine (with OH group) or 4,4′‐diaminodiphenyl ether (without OH group). The onset and maximum of the exotherm due to the ring‐opening polymerization for the pristine Ba appeared on differential scanning calorimetry curves around 200 and 240 °C, respectively. In the presence of poly(imide‐siloxane)s, the exothermic temperatures were lowered: the onset to 130–140 °C and the maximum to 210–220 °C. The exotherm due to the benzoxazine polymerization disappeared after curing at 240 °C for 1 h. Viscoelastic measurements of the cured blends containing poly(imide‐siloxane) with OH functionality showed two glass‐transition temperatures (Tg's), at a low temperature around −55 °C and at a high temperature around 250–300 °C, displaying phase separation between PDMS and the combined phase consisting of polyimide and polybenzoxazine (PBa) components due to the formation of AB‐crosslinked polymer. For the blends containing poly(imide‐siloxane) without OH functionalities, however, in addition to the Tg due to PDMS, two Tg's were observed in high‐temperature ranges, 230–260 and 300–350 °C, indicating further phase separation between the polyimide and PBa components due to the formation of semi‐interpenetrating networks. In both cases, Tg increased with increasing poly(imide‐siloxane) content. Tensile measurements showed that the toughness of PBa was enhanced by the addition of poly(imide‐siloxane). Thermogravimetric analysis showed that the thermal stability of PBa also was enhanced by the addition of poly(imide‐siloxane). © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2633–2641, 2001
Temperature‐induced aggregation of the copolymers of N‐isopropylacrylamide and sodium 2‐acrylamido‐2‐methyl‐1‐propanesulphonate in aqueous solutions
Authors: Szczubiałka Krzysztof , Loska Rafał , Nowakowska Maria 
Published: August 2002

AbstractA series of random copolymers of N‐isopropylacrylamide (NIPAM) and sodium 2‐acrylamido‐2‐methyl‐1‐propanesulphonate (AMPS) was synthesized by free‐radical copolymerization. The content of AMPS in the copolymers ranged from 1.1 to 9.6 mol %. The lower critical‐solution temperature (LCST) of copolymers in water increased strongly with an increasing content of AMPS. The influence of polymer concentration on the LCST of the copolymers was studied. For the copolymers with a higher AMPS content, the LCST decreased faster with an increasing concentration than for copolymers with a low content of AMPS. For a copolymer containing 1.1 mol % of AMPS the LCST dropped by about 3 °C when the concentration increased from 1 to 10 g/L, whereas for a copolymer containing 9.6 mol % of AMPS the LCST dropped by about 10 °C in the concentration range from 2 to 10 g/L. It was observed that the ionic strength of the aqueous polymer solution very strongly influences the LCST. This effect was most visible for the copolymer with the highest content of AMPS (9.6 mol %) for which an increase in the ionic strength from 0.2 to 2.0 resulted in a decrease in the LCST by about 27 °C (from 55 to 28 °C), whereas for the copolymer containing 1.1 mol % of AMPS the LCST decreased only by about 6 °C (from 37 to 31 °C) when the ionic strength increased from 0.005 to 0.3. The reactivity ratios for the AMPS and NIPAM monomer pairs were determined using different methods. The values of rAMPS and rNIPAM obtained were 11.0–11.6 and 2.1–2.4, respectively. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2784–2792, 2001