bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bulk cyclopolymerization of 1,2:5,6‐diepithio‐3,4‐di‐O‐methyl‐1,2:5,6‐tetradeoxy‐D‐mannitol with quaternary ammonium salts leading to gel‐free thiosugar polymer
Authors: Satoh Toshifumi , Imai Tomoko , Sugie Norihiko , Nonokawa Ryuji , Yokota Kazuaki , Kakuchi Toyoji 
Published: August 2002

AbstractThe bulk cyclopolymerization of diepisulfide, 1,2:5,6‐diepithio‐3,4‐di‐O‐methyl‐1,2:5,6‐tetradeoxy‐D‐mannitol (1), was studied using R4N+Br− (R = CH3, C2H5, C3H7, C4H9, and C7H15) and (C4H9)4N+X− (X = Cl, I, NO3, and ClO4) as the initiators. All the bulk polymerizations of 1 using quaternary tetraalkylammonium salts at 90 °C proceeded without gelation even at high conversion to produce gel‐free polymers consisting of 2,5‐anhydro‐1,5‐dithio‐D‐glucitol (I) as the major cyclic repeating unit along with 1,5‐anhydro‐2,5‐dithio‐D‐mannitol (II) and the desulfurized acyclic unit (III) as the minor units. The polymerization rate and molar fraction of the I unit increased with the increasing alkyl chain length of the tetraalkylammonium cation and the increasing nucleophilicity of the counteranion. Tetrabutylammonium chloride exhibited the highest catalytic activity and the highest stereoselectivity, that is, the thiosugar polymer with I:II:III = 81:15:4 and a number‐average molecular weight of 31.9 × 103 was obtained in 85% yield for a polymerization time of 0.5 h. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 965–970, 2002
Photoinitiators with functional groups. V. New water‐soluble photoinitiators containing carbohydrate residues and copolymerizable derivatives thereof
Authors: Liska Robert 
Published: August 2002

AbstractThe synthesis of new water‐soluble photoinitiators (PIs) based on hydroxyalkylphenones, benzophenones, and thioxanthones with carbohydrate residues such as glucose, cellobiose, and 1‐amino‐1‐deoxy‐D‐glucitol (glucamine) is described. In addition, selected initiators were reacted with methacryloyl chloride to obtain copolymerizable initiators with improved migration stability. Results from photo differential scanning calorimetry and gel‐content measurements in commercially available water‐thinnable and emulsion‐type resins as well as 2‐hydroxyethyl acrylate are included. Glucose‐modified PIs gave the best results with respect to compatibility with the resin, reactivity, and gel content. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1504–1518, 2002
Star poly(methyl methacrylate) with end‐functionalized arm chains by ruthenium‐catalyzed living radical polymerization
Authors: Baek Kyung‐Youl , Kamigaito Masami , Sawamoto Mitsuo 
Published: August 2002

AbstractStar polymers with end‐functionalized arm chains (surface‐functionalized star polymers) were synthesized by the in situ linking reaction between ethylene glycol dimethacrylate (linking agent) and an α‐end‐functionalized linear living poly(methyl methacrylate) in RuCl2(PPh3)3‐catalyzed living radical polymerization; the terminal on the surface functionalities included amides, alcohols, amines, and esters. The star polymers were obtained in high yields (75–90%) with initiating systems consisting of a functionalized 2‐chloro‐2‐phenylacetate or ‐acetamide [FC(O)CHPhCl; F = nPrNH, HOCH2CH2O, Me2NCH2CH2O, or EtO; initiator] and n‐Bu3N (additive). The yield was lower with a functionalized 2‐bromoisobutyrate [Me2NCH2CH2OC(O)CMe2Br] initiator or with Al(Oi‐Pr)3 as an additive. Multi‐angle laser light scattering analysis showed that the star polymers had arm numbers of 10–100, radii of gyration of 6–23 nm, and weight‐average molecular weights of 1.3 × 105 to 3.0 × 106, which could be controlled by the molar ratio of the linking agent to the linear living polymers. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1972–1982, 2002
Synthesis of poly(lactide‐ran‐MOHEL) and its biodegradation with proteinase K
Authors: Shirahama Hiroyuki , Mizuma Kiyoshi , Umemoto Koichi , Yasuda Hajime 
Published: August 2002

AbstractHomopoly(L‐lactide) and homopoly(D,L‐lactide) were almost inert for biodegradation with tricine buffer or normal enzymes such as bromelain, pronase, and cholesterol esterase but biodegradable with proteinase K. Significantly enhanced biodegradation was observed when an optically active (R)‐ or (S)‐3‐methyl‐4‐oxa‐6‐hexanolide (MOHEL) unit was introduced into poly(L‐lactide) [poly(L‐LA)] or poly(D,L‐lactide) [poly(D,L‐LA)] sequences. Poly[L‐LA‐ran‐(R)‐MOHEL] in molar ratios of 86/14 to 43/57 showed good biodegradability that was independent of crystallinity. The biodegradation of polymers with proteinase K increased in the following order: poly[D,L‐LA‐ran‐(R)‐MOHEL] > poly[L‐LA‐ran‐(R)‐MOHEL] > poly[D,L‐LA‐ran‐(S)‐MOHEL] > poly[L‐LA‐ran‐(S)‐MOHEL] > poly(R)‐MOHEL > poly(D,L‐LA). The number‐average molecular weight, molecular weight distribution, glass‐transition temperature, and melting temperature did not change before and after the biodegradation of poly[L‐LA‐ran‐(R)‐MOHEL], indicating that the degradation occurred from the polymer surface. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1374–1381, 2001
Enhanced dissolution of copolymers bearing photobase‐ or photoacid‐generating groups in polar solvents by photochemical formation of ionic pairs
Authors: Suyama Kanji , Yamaguchi Shizue , Shirai Masamitsu , Tsunooka Masahiro 
Published: August 2002

AbstractSolubility changes in the irradiation of copolymers bearing photoacid‐ or photobase‐generating groups and low molecular weight photobase generators (PBGs) or photoacid generators (PAGs) were investigated. Copolymers bearing acyloxyimino (AOI) groups were used as those generating pendant amino groups photochemically. Copolymers bearing o‐nitrobenzyloxycarbonyl and imino sulfonate groups were used as those generating carboxy and sulfo groups, respectively. The solubility of copolymers bearing AOI groups into polar solvents was enhanced by added PAGs such as β‐keto sulfones or imino sulfonates after irradiation. A similar enhancement was observed in copolymers bearing o‐nitrobenzyloxycarbonyl groups in the presence of PBGs such as oxime esters or o‐nitrobenzyl carbamates. These results showed that the formation of acid–base pairs on irradiation was effective for dissolution into polar solvents. Copolymers bearing imino sulfonate groups showed a high solubility, and no such enhancement was observed by PBG. Films of copolymers bearing β‐keto sulfone groups became insoluble because of crosslinking. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1708–1715, 2001
Fast and convenient construction of carbamate/urea‐based dendrimers with a diisocyanate building block
Authors: Peerlings H. W. I. , Van Benthem R. A. T. M. , Meijer E. W. 
Published: August 2002

AbstractA novel, fast, and simple synthetic procedure for polycarbamate/urea dendrimers, based on an AB–CD2 coupling strategy, is presented. The reactivity difference of the two isocyanate functionalities of the AB building block allows the construction of these dendrimers without the necessity of activation or deprotection steps. This makes it possible to construct dendrimers within 2–3 days, even the largest dendrimers. The resulting dendrimers could be fully characterized by 13C NMR, IR spectroscopy, and mass spectrometry. The synthetic strategy necessitates only techniques such as stirring, heating, and accurate dosing, and there is no workup required for the purification of the compounds. On account of a wide variety of polyols, amines, and aminoalcohols, this new procedure is not limited to the synthetic strategy followed but allows the incorporation of a large variety of functional molecules in the core, in the branching units, or at the end groups. The method is even applicable when organometallic species are incorporated into the dendritic structure, thereby showing its versatility. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3112–3120, 2001
Conformational contribution to the heat capacity of the starch and water system
Authors: Pyda Marek 
Published: August 2002

AbstractThe heat capacities of starch and starch—water have been measured with adiabatic calorimetry and standard differential scanning calorimetry and are reported from 8 to 490 K. The amorphous starch containing 11–26 wt % (53–76 mol %) water shows a partial glass transition decreasing from 372 to 270 K, respectively. Even the dry amorphous starch gradually increases in heat capacity above 270 K beyond that set by the vibrational density of states. This gradual increase in the heat capacity is identified as part of the glass transition of dry starch that is, however, not completed at the decomposition temperature. The heat capacities of the glassy, dry starch are linked to an approximate group vibrational spectrum with 44 degrees of freedom. The Tarasov equation is used to estimate the heat capacity contribution due to skeletal vibrations with the parameters Θ1 = 795.5 K, Θ2 = 159 K, and Θ3 = 58 K for 19 degrees of freedom. The calculated and experimental heat capacities agree better than ±3% between 8 and 250 K. Similarly, the vibrational heat capacity has been estimated for glassy water by being linked to an approximate group vibrational spectrum and the Tarasov equation (Θ1 = 1105.5 K and Θ3 = 72.4 K, with 6 degrees of freedom). Below the glass transition, the heat capacity of the solid starch—water system has been estimated from the appropriate sum of its components and also from a direct fitting to skeletal vibrations. Above the glass transition, the differences are interpreted as contributions of different conformational heat capacities from chains of the carbohydrates interacting with water. The conformational parts are estimated from the experimental heat capacities of dry starch and starch—water, decreased by the vibrational and external contributions to the heat capacity. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 3038–3054, 2001
Nonisothermal crystallization kinetics of polypropylene/montmorillonite nanocomposites
Authors: Xu Weibing , Ge Mingliang , He Pingsheng 
Published: August 2002

AbstractThe nonisothermal crystallization kinetics of poly(propylene) (PP) and poly(propylene)/organic‐montmorillonite (PP/Mont) nanocomposite were investigated by differential scanning calorimetry (DSC) with various cooling rates. The Avrami analysis modified by previous research was used to describe the nonisothermal crystallization process of PP and PP/Mont nanocomposite very well. The values of half‐time and Zc showed that the crystallization rate increased with increasing cooling rates for both PP and PP/Mont nanocomposite, but the crystallization rate of PP/Mont nanocomposite was faster than that of PP at a given cooling rate. The activation energies were estimated by the Kissinger method, and the values were 189.4 and 155.7 kJ/mol for PP and PP/Mont nanocomposite, respectively. PP/Mont nanocomposite could be easily fabricated as original PP, although the addition of organomontmorillonite might accelerate the overall nonisothermal crystallization process. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 408–414, 2002; DOI 10.1002/polb.10101
Stress distribution in poly‐p‐phenylenebenzobisoxazole (PBO) fiber as viewed from vibrational spectroscopic measurement under tension. I. Stress‐induced frequency shifts of Raman bands and molecular deformation mechanism
Authors: Kitagawa Tooru , Tashiro Kohji , Yabuki Kazuyuki 
Published: August 2002

AbstractTo clarify the relationship between a molecular deformation mechanism and a high Young's modulus of poly‐p‐phenylenebenzobisoxazole (PBO), Raman spectra were measured for fibers subjected to a tensile stress along the chain axis. The stress‐induced frequency shift of the observed Raman bands could be reproduced reasonably by the normal‐mode calculation under a quasi‐harmonic approximation. The frequency position at zero stress and the shift factor of Raman bands were predicted for a PBO chain that agreed with the actually evaluated values. On the basis of these analyses, the molecular deformation mechanism of the PBO chain has been discussed in detail. The crystalline modulus of the PBO chain was calculated theoretically to be 458 GPa, in good agreement with the X‐ray observed value of 460 GPa. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1269–1280, 2002
Degradation of polymer coating systems studied by positron annihilation spectroscopy. IV. Oxygen effect of UV irradiation
Authors: Zhang R. , Chen H. , Cao H. , Huang C.‐M. , Mallon P. E. , Li Y. , He Y. , Sandreczki T. C. , Jean Y. C. , Suzuki R. , Ohdaira T. 
Published: August 2002

AbstractThe effect of oxygen on the photodegradation of a polyurethane coating induced by accelerated UV irradiation was studied with two different light sources: 313‐nm UVB and Xe lamps. Doppler‐broadened energy spectra (DBES) and positron annihilation lifetimes were measured as a function of incident positron energy (0–30 keV) and irradiation time (0–100 h). The photodegradation of the coating was characterized in terms of subnanometer defect changes. Significant variations of the S parameter (a defect parameter from DBES) and the ortho‐positronium lifetime and intensity were observed as a function of oxygen concentration during exposure to UV irradiation. These results showed a significant enhancement in photodegradation due to the presence of oxygen, as indicated by a decrease in free volume and holes at the atomic level. Enhanced degradation in the presence of oxygen, as indicated by increased free‐radical production (observed with electron spin resonance spectroscopy), was also observed. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2035–2047, 2001
Shared decision‐making in question
Authors: Charavel Marie , Bremond Alain , Moumjid‐Ferdjaoui Nora , Mignotte Herve , Carrere Marie Odile 
Published: August 2002

AbstractOver recent years, communication within the physician–patient relationship has been profoundly changing. New modes of conveying diagnostic and therapeutic information influence the way in which decisions regarding treatment are made. We propose a critical review of the various theoretical models as presented in the literature, from the paternalistic to the shared decision model, in order to reveal conceptual ambiguities and their related methodological problems. This analysis leads to a project for clarifying these problems through a research protocol based on shared decision‐making. Copyright © 2001 John Wiley & Sons, Ltd.
The eortc QLQ‐C30 (version 3.0) quality of life questionnaire: validation study for Spain with head and neck cancer patients
Authors: Arraras J.I. , Arias F. , Tejedor M. , Pruja E. , Marcos M. , Martínez E. , Valerdi J. 
Published: August 2002

AbstractThe EORTC Quality of Life Study Group has developed a questionnaire for evaluating Quality of Life in international clinical trials: QLQ‐C30. The purpose of the present work is to validate the third version of this questionnaire (3.0) for use in Spain.Two hundred and one head and neck cancer patients completed the QLQ‐C30 at one or two time points during the treatment and follow‐up periods, and a subsample completed the questionnaire on three occasions. Psychometric evaluation of the structure, reliability and validity of the questionnaire was undertaken.The data support the structure and the reliability of the scales. Validity was confirmed in three ways: the interscale correlations are statistically significant and moderate, several scales and items discriminate among groups of patients with different scores on the clinical variables, and some scales reflect significant changes during treatment and the follow‐up period.The EORTC QLQ‐C30 (version 3.0) is a reliable and valid questionnaire when applied to a sample of Spanish head and neck cancer patients. These results are in line with previous studies. Copyright © 2002 John Wiley & Sons, Ltd.
Glacial and periglacial phenomena in Ethiopia: a review
Authors: Grab Stefan 
Published: August 2002

AbstractThe glacial and periglacial geomorphology for the Simen and Bale Mountains in Ethiopia is reviewed. The Simen Mountains are mostly absent of relict periglacial landforms and today host a variety of miniature cryogenic phenomena. The Bale Mountains host a few localized large relict cryogenic landforms (e.g. stone stripes), suggesting past sporadic permafrost. A variety of regional factors may have contributed to the more extensive periglacial activity in southern Ethiopia than in the higher Simen Mountains to the north. Copyright © 2002 John Wiley & Sons, Ltd.
Benefits of thickened feeds in previously healthy infants with respiratory syncytial viral bronchiolitis
Authors: Khoshoo Vikram , Ross Gerald , Kelly Beth , Edell Dean , Brown Shannan 
Published: August 2002

AbstractInfants with respiratory syncytial virus (RSV) bronchiolitis have an increased risk of aspiration. The optimal feeding strategy for these patients has not been described. Fifteen previously healthy and clinically stable infants with RSV bronchiolitis underwent video‐fluoroscopy studies to assess swallowing using thin barium. Those with abnormal studies underwent a repeat study, using barium that was thickened with rice cereal.Nine of 15 infants had abnormal studies with thin barium. Laryngeal or tracheal penetration with thin barium was seen in 3 and 2 infants, respectively, but not with thickened barium. Aspiration of thin barium was seen in 4 infants, but it corrected in 3 of these 4 infants with thickened barium.Thickened feeds provide a simple, safe, and cost‐effective intervention to improve swallowing dysfunction and prevent aspiration in infants with RSV bronchiolitis. Pediatr Pulmonol. 2001; 31:301–302. © 2001 Wiley‐Liss, Inc.
Bronchoscopic instillation of surfactant in acute respiratory distress syndrome
Authors: Nakamura Craig T. , Ripka James F. , McVeigh Karen , Kapoor Neena , Keens Thomas G. 
Published: August 2002

AbstractAbnormalities of surfactant action in acute respiratory distress syndrome (ARDS) result in decreased lung compliance and significant hypoxemia. Several case reports and small studies suggest that there is an improvement in patients with ARDS following the administration of surfactant. However, there is no clear‐cut ideal method for surfactant administration. The bronchoscopic administration of surfactant may represent an effective method of surfactant delivery in ARDS. Bronchoscopic instillation offers the theoretical advantages that the surfactant may be distributed directly to the desired regions of the lung, a more economical use of surfactant, and the opportunity to lavage leaked serum proteins prior to instillation. Surfactant has been administered in adults with success. We present a case of initial improvement in oxygenation index, ventilation index, and mechanical ventilatory support in a pediatric patient with ARDS following the bronchoscopic administration of surfactant. Pediatr Pulmonol. 2001; 31:317–320. © 2001 Wiley‐Liss, Inc.
Reduction of oscillatory pressure along the endotracheal tube is indicative for maximal respiratory compliance during high‐frequency oscillatory ventilation: A mathematical model study
Authors: van Genderingen H.R. , Versprille A. , Leenhoven T. , Markhorst D.G. , van Vught A.J. , Heethaar R.M. 
Published: August 2002

AbstractWe hypothesized that during high‐frequency oscillatory ventilation (HFOV), a reduction of peak‐to‐peak oscillatory pressure along the endotracheal tube is maximal when respiratory system compliance is maximal. We made a mathematical model of the endotracheal tube and the respiratory system of a neonate suffering from idiopathic respiratory distress syndrome (IRDS). The model consisted of linear viscous and inertive elements, a non‐linear endotracheal tube resistance, and a non‐linear compliance allowing for alveolar recruitment and overdistention. Respiratory compliance was maximal at the transition between maximal recruitment and minimal overdistention. A new variable, the oscillatory pressure ratio (OPR), was defined as the ratio between peak‐to‐peak oscillatory pressures at the distal end and the proximal opening of the endotracheal tube, respectively. The respiratory variables of four patients were fed into the model, and the relationship between respiratory system compliance and OPR was determined.OPR decreased as compliance increased, except for very low compliances below where 0.08 mL · cmH2O−1, and OPR increased with increasing compliance. The relationship between mean airway pressure P̄aw and OPR revealed that the minimal OPR (range, 0.37–0.78) and maximal respiratory compliance coincided at the same P̄aw. However, the relationship did depend on oscillation frequency, applied oscillatory pressure, and endotracheal tube resistance, parameters that may change during clinical application of HFOV. When 81 permutations of nominal and extreme respiratory variables were used in the model, the minimum OPR (0.60 ± 0.23) and maximum compliance coincided in all cases.These model experiments support our hypothesis. The results indicate that the OPR may be a useful index to optimize lung expansion, where lung recruitment is maximal and overdistention minimal. In vivo tests will be needed to reveal the feasibility and reliability of such an index for biomedical and clinical application. Pediatr Pulmonol. 2001; 31:458–463. © 2001 Wiley‐Liss, Inc.
Effects of fetal growth restriction on lung development before and after birth: A morphometric analysis
Authors: Maritz G.S. , Cock M.L. , Louey S. , Joyce B.J. , Albuquerque C.A. , Harding R. 
Published: August 2002

AbstractOur aim was to determine the effects of fetal growth restriction (FGR) during late gestation on the structure of the lungs in the fetus near term and at 8 weeks after birth. The studies were performed using two groups of pregnant sheep and their offspring. In both groups, FGR was induced by umbilico‐placental embolisation (UPE); for fetal studies, UPE was performed from 120 days of gestation until 140 days (term, ∼146 days), when fetuses were killed for tissue analysis. For postnatal studies, UPE continued from 120 days until delivery at term; postnatal lambs were killed at 8 weeks after birth for tissue analysis.UPE led to a thicker pulmonary blood‐air barrier at 140 days of gestation and this difference, which was due to a thickened basement membrane, was still present at 8 weeks after birth. At 8 weeks, we also observed a smaller number of alveoli per respiratory unit, thicker interalveolar septa, and a greater volume density of lung tissue in FGR lambs compared to controls. These changes would be expected to impair gas exchange and alter the mechanical properties of the lungs.Our data show that structural alterations in the lungs induced by placental insufficiency were more evident at 8 weeks of postnatal age than near term, indicating that the effects of FGR on the lung may become more serious with age and may affect respiratory health later in life. Pediatr Pulmonol. 2001; 32:201–210. © 2001 Wiley‐Liss, Inc.