bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface enrichment and crystallization of polyamide and polytetrafluoroethylene blend
Authors: Song Rui , Yang Debin , He Linghao , Yao Guangtao 
Published: November 2006

AbstractThe blend surface of polyamide 6 and polytetrafluoroethylene (PA 6/PTFE) and its change as a function of annealing time are investigated by means of attenuated total reflection (ATR)‐FTIR spectroscopy, contact angle (CA) measurement, as well as atomic force microscopy (AFM) under ambient condition; meanwhile the surface elemental compositions are obtained by X‐ray photoelectron spectroscopy (XPS). The results show that the addition of fluoro content can decrease the surface energy compared with the pure polyamide, while, an evident influence on the surface energy has not been detected with increasing fluoro contents. Upon annealing at 120 °C, there is a profound enrichment of the low‐surface energy component to the sample surface; yet this situation becomes more complex when samples are annealed at 150 °C—not only the segregation effect from the low surface energy PTFE, but also the crystallization of the PA 6 will come into play for the blend with 50% PTFE. These observations are ascribed to the presence of the polar group of the polyamide component, as well as its strong tendency to crystallize when subjected to thermal treatment at sufficiently high temperatures, and this behavior would basically offset the segregation tendency of fluoro component to the sample surface. This assumption is further corroborated by the XPS measurement in the current researches. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 138–152, 2007
Development of morphology and properties of injection‐molded bars of HDPE/PA6 blends along flow direction
Authors: Li Jiang , Yu Xiaofeng , Guo Shaoyun 
Published: December 2006

AbstractThe structure and mechanical properties of injection‐molded bars of high‐density polyethylene (HDPE)/PA6 blends were studied in this article. The experimental results showed that the morphologies of injection‐molded bars change gradually along the flow direction, which is tightly related to the melt viscosity and processing conditions. The higher melt viscosity, lower mold temperature, and shorter packing time, restricting the macromolecular relaxation, enhance the difference in morphologies and properties at near and far parts of a mold. An injection‐molded bar (namely H2C5), consisting of 75 wt % of HDPE, 20 wt % of PA6, and 5 wt % of compatibilizer (HDPE‐g‐MAH), showed a greater difference in mechanical properties at near and far parts because of its higher melt viscosity. A clear interface between the skin and core layers of near part in it leads to a much higher impact strength than that of far part. And tensile tests show that its tensile strength of near part is higher than that of far part due to the higher orientation degrees of HDPE matrix and PA6 dispersed phase in near part. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 184–195, 2007
Side‐chain crystallization behavior of graft copolymers consisting of an amorphous main chain and crystalline side chains. II. Poly(n‐hexyl methacrylate)‐graft‐poly(ethylene glycol)
Authors: Inomata Katsuhiro , Fukuda Chieko , Hori Kuniyoshi , Sugimoto Hideki , Nakanishi Eiji 
Published: November 2006

AbstractThe phase behavior and crystallization of graft copolymers consisting of poly(n‐hexyl methacrylate) (PHMA) as an amorphous main chain and poly(ethylene glycol) (PEG) as crystallizable side chains (HMAxwith 15 ≤x≤ 73, wherexrepresents the weight percentage of PEG) were investigated. Small‐angle X‐ray scattering profiles measured above the melting temperature of PEG suggested that a microdomain structure with segregated PHMA and PEG domains was formed in HMA40 and HMA46. This phase behavior was qualitatively described by a calculated phase diagram based on the mean‐field theory. Because of the segregation of PEG into microdomains, the crystallization temperature of the PEG side chains in HMAxwas higher than that in poly(methyl acrylate)‐graft‐poly(ethylene glycol) having a similar value ofx, which was considered to be in a disordered state above the melting temperature. In HMAxwithx≤ 40, PEG crystallization was strongly restricted, probably because the PEG microdomains were isolated in the PHMA matrix. As a result, the growth of PEG spherulite was not observed because the PEG crystallization occurred after vitrification of the PHMA segregated domains. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 129–137, 2007
Prostate cells express two isoforms of fibroblast growth factor receptor 1 with different affinities for fibroblast growth factor‐2
Authors: Roghani Monireh , Moscatelli David 
Published: December 2006

AbstractBackgroundFibroblast growth factor receptor 1 (FGFR1) mRNA can be alternatively spliced to generate isoforms containing (FGFR1α) or lacking (FGFR1β) the first immunoglobulin‐like domain. We examined which isoforms are expressed by cultured prostate cells, their affinities for FGF‐2, and the effect of heparin on FGF‐2 binding.MethodsFGFR1 isoform expression was examined by RT‐PCR. FGFR1α and FGFR1β were expressed in CHO cells mutant in heparan sulfate synthesis, and their affinities for FGF‐2, FGF‐1, FGF‐4, and FGF‐6 were determined in the presence and absence of heparin.ResultsFGFR1α was expressed in luminal epithelial cells, whereas FGFR1β was expressed in basal epithelial and smooth muscle cells. FGFR1β bound FGF‐2 with three–fourfold higher affinity than FGFR1α both in the presence and absence of heparin. Heparin increased affinity of both receptor isoforms for FGF‐2 approximately four–fivefold.ConclusionsProstate smooth muscle and basal epithelial cells are likely to be more sensitive than luminal epithelial cells to the low concentrations of FGFs present in vivo. Prostate © 2006 Wiley‐Liss, Inc.
Structural insights into the GTPase domain of Escherichia coli MnmE protein
Authors: Monleón Daniel , Martínez‐Vicente Marta , Esteve Vicent , Yim Lucia , Prado Silvia , Armengod Maria‐Eugenia , Celda Bernardo 
Published: December 2006

AbstractThe Escherichia coli MnmE protein is a 50‐kDa multidomain GTPase involved in tRNA modification. Its homologues in eukaryotes are crucial for mitochondrial respiration and, thus, it is thought that the human protein might be involved in mitochondrial diseases. Unlike Ras, MnmE shows a high intrinsic GTPase activity and requires effective GTP hydrolysis, and not simply GTP binding, to be functionally active. The isolated MnmE G‐domain (165 residues) conserves the GTPase activity of the entire protein, suggesting that it contains the catalytic residues for GTP hydrolysis. To explore the GTP hydrolysis mechanism of MnmE, we analyzed the effect of low pH on binding and hydrolysis of GTP, as well as on the formation of a MnmE transition state mimic. GTP hydrolysis by MnmE, but not GTP binding or formation of a complex with mant‐GDP and aluminium fluoride, is impaired at acidic pH, suggesting that the chemistry of the transition state mimic is different to that of the true transition state, and that some residue(s), critical for GTP hydrolysis, is severely affected by low pH. We use a nuclear magnetic resonance (NMR)‐based approach to get insights into the MnmE structure and properties. The combined use of NMR restraints and homology structural information allowed the determination of the MnmE G‐domain structure in its free form. Chemical shift structure‐based prediction provided a good basis for structure refinement and validation. Our data support that MnmE, unlike other GTPases, does not use an arginine finger to drive catalysis, although Arg252 may play a role in stabilization of the transition state. Proteins 2007. © 2006 Wiley‐Liss, Inc.
Thermoelectric properties and phase transitions of II–VI semiconductors at high pressure
Authors: Shchennikov Vladimir V. , Ovsyannikov Sergey V. 
Published: December 2006

AbstractThe high‐pressure phase transitions in II–VI semiconductors (HgTe, HgSe, HgS, HgO, CdTe, CdSe, CdS, ZnTe, ZnSe, ZnS, ZnO) are analyzed in light of recent findings. A contribution is emphasized of the thermoelectric power (Seebeck effect) technique to registration of new electronic phases and to prediction of their related structural modifications. A novel thermopower study of ZnX (X–Te, Se, S) revealed a difference between the high‐pressure NaCl phases of ZnSe and ZnS and the orthorhombic Cmcm phase of ZnTe. Mechanisms of the pressure‐induced transitions in ZnX and other II–VI compounds are discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Non‐parametric bounds on treatment effects with non‐compliance by covariate adjustment
Authors: Cai Zhihong , Kuroki Manabu , Sato Tosiya 
Published: November 2006

AbstractConsider a clinical trial where subjects are randomized to two treatment arms but compliance to the assignment is not perfect. Concerning this problem, this paper derives non‐parametric bounds on treatment effects by making use of the observed covariates information. The new bounds are narrower and more informative than the existing ones. In addition, a new non‐parametric point estimation approach is proposed based on stratified analysis. Furthermore, to examine the accuracy of estimating the proposed bounds, we provide variance estimators for the proposed approach. The results of this paper can yield credible information on treatment effects, which will be useful for medical research and public health policy analysis. Copyright © 2006 John Wiley & Sons, Ltd.
A Thai community's anniversary reaction to a major catastrophe
Authors: Assanangkornchai Sawitri , Tangboonngam Sa‐nguansri , Sam‐angsri Nisan , Edwards J. Guy 
Published: December 2006

AbstractThe aim of this study was to investigate changes in the prevalence of adverse stress reactions in different areas of Hat Yai during the year immediately following a major natural disaster—the flood of 2000. Samples of around l00 residents of each of four areas exposed to different degrees of severity of the stressors caused by the flood were followed‐up at 8 to l0 week intervals. When first interviewed on entry into the study, the respondents were invited to complete a structured questionnaire that sought information on their personal characteristics, data on the various flood‐related stressors to which they were exposed, and their responses to these stressors. They also completed a Thai version of the 12‐item General Health Questionnaire and the Impact of Events Scale at each of the five data collection times. There was a gradual decline in the scores on these instruments over the l2 month period but, on the anniversary of the flood, there was an increase in scores among residents confined to those areas of Hat Yai where the risk and/or consequences of severe flooding was highest and where rescue work was most difficult. This is considered to be the first epidemiological study of a major civilian disaster that has demonstrated an increase in prevalence of stress‐related symptoms as an anniversary reaction within a community. Copyright © 2006 John Wiley & Sons, Ltd.
The factorial validity and measurement invariance of the Maslach Burnout Inventory for human services
Authors: Vanheule Stijn , Rosseel Yves , Vlerick Peter 
Published: December 2006

AbstractThis paper first examines the factorial validity of the Maslach Burnout Inventory for human services professions (MBI‐HSS). The authors test the original 22‐item version and a shortened 20‐item version. Model fit is evaluated with confirmatory factor analysis starting with data collected from a sample of hospital nurses (n = 2515) and a sample of nurses and assistants working in residential welfare institutions (n = 1639). Only the fit of the 20‐item MBI‐HSS was good in both samples. Next the hypothesis of measurement invariance of the 20‐item MBI‐HSS across the samples is examined, but this hypothesis does not hold. Partial invariance at the level of the subscales also could not be confirmed. The authors conclude that for hospital nurses the MBI‐HSS factors mean something other than what they mean for professionals working in welfare institutions, and suggest that future research could focus upon this difference. Copyright © 2006 John Wiley & Sons, Ltd.
Physical Aging of Amorphous Starches (A Review)
Authors: Chung Hyun‐Jung , Lim Seung‐Taik 
Published: November 2006

AbstractIn recent years, physical behaviors of glassy foods are greatly focused as many processed foods are consumed in their glassy states. Physical aging is one of the important phenomena for glassy foods, which is responsible for quality changes vs. retention of freshness during storage. The aging phenomenon can be predicted on the basis of a process of thermodynamic relaxation, induced by structural rearrangements in amorphous matrices. Thus, it can be evaluated by using calorimetric, volumetric, and mechanical analyses. Starch is one of the principal components in most cereal‐based glassy foods, and its aging is thus relevant to the overall changes in quality and freshness of various cereal‐based food products. The polymeric theory for the physical aging of glassy starch is reviewed on the basis of the existing literature, and the aging kinetics based on the changes in various physical and thermal properties are discussed.
A study of the effect of sustained, whole‐school professional development on student achievement in science
Authors: Johnson Carla C. , Kahle Jane Butler , Fargo Jamison D. 
Published: December 2006

AbstractThis longitudinal study of middle school science teachers explored the relationship, if any, between teacher participation in whole‐school, sustained, collaborative professional development and student achievement in science. Eleven teachers from Glendale Middle School participated in the Discovery Model Schools Initiative 2‐week summer institute, followed by monthly release day professional development sessions focused on implementing instruction outlined in the National Science Education Standards. Student achievement was assessed using the Discovery Inquiry Test in Science. The same students completed the test in grades 6–8. Students of teachers at Glendale Middle School significantly outperformed students at the control school. Findings in this study revealed the positive impact that whole‐school, sustained, collaborative professional development programs have on student achievement, indicating that programs of this nature could be a means to narrowing or eliminating achievement gaps in science. © 2006 Wiley Periodicals, Inc. J Res Sci Teach 44: 775–786, 2007
Verbessertes Kaltkathoden‐Ionisationsmanometer mit verlängerter Lebensdauer
Authors: Wilfert Stefan , Edelmann Christian 
Published: November 2006

AbstractWird ein Kaltkathoden‐Ionisationsmanometer in einer kohlenwasserstoffhaltigen Gasatmosphäre bei hohen Drücken im Vakuumbereich betrieben, dann wird die mittlere Lebensdauer des Manometers durch eine Kontamination der Elektroden und damit durch eine starke Veränderung der Entladungsstrom‐Druck‐Kennlinie begrenzt. Infolgedessen liefert das Messgerät nach einer gewissen Betriebszeit entweder keine verlässliche Druckanzeige mehr oder kann im ungünstigsten Fall ganz ausfallen. Im Folgendem wird ein verbessertes Kaltkathoden‐Ionisationsvakuummeter vom inversen Magnetron‐Typ vorgestellt, welches speziell für den Langzeitbetrieb in stark kohlenwasserstoffhaltigen Restgasatmosphären konzipiert wurde. Der Messkopf weist bei annähernd konstanter Messgenauigkeit eine mindestens 3‐fach höhere Lebensdauer als kommerziell erhältliche Kaltkathoden‐Messröhren auf. Erreicht wurde dies durch die Verwendung zweier getrennter Entladungskammern in einem gemeinsamen Messröhrengehäuse, wobei die am Röhreneingang positionierte Entladungszone lediglich als Ionenbaffle wirkt und die weiter innen liegende Entladung als Messgrundlage fungiert. Es werden der Prototyp des entwickelten kontaminationsarmen inversen Doppelmagnetrons vorgestellt und Untersuchungsergebnisse zum Langzeitmessverhalten präsentiert.
Gießformherstellung durch Beschichtung von Modellen
Authors: Schebesta Thomas , Heikenwälder Jürgen , Zimmer Otmar 
Published: November 2006

AbstractEs wird eine neuartige Werkzeug‐ und Formenbautechnologie zur kostengünstigen Herstellung standzeitoptimierter Formwerkzeuge vorgestellt. Mit dieser Technologie ist die wirtschaftliche Fertigung von Prototypen und Kleinserien auch im schwer verarbeitbaren Serienwerkstoff möglich.Das entwickelte innovative Herstellverfahren für Gießformen und Spritzgießwerkzeuge basiert auf der Abformung eines Positivmodells durch Schichtverbunde. Diese, die Geometrie des Modells speichernden, grenzflächenoptimierten Schichtverbunde bilden mit einer Hinterfütterung nach Entfernen des Teiles und dem Anbringen der gießtechnischen Einrichtung die Werkzeugstammform. Der Aufbau der Schichtverbunde erfolgt mit aktivierten Bogenbeschichtungsverfahren (PVD‐Verfahren) für die die spätere Werkzeugoberfläche bildende Funktionsschicht und durch Plasmaspritzbeschichten (APS) für die Stützschicht.Mit einem derart hergestellten Spritzgießwerkzeug können mehr als 1000 Teile eines mit Glasfasern verstärkten Kunststoffes oder mehr als 1500 Teile eines unverstärkten Kunststoffes in hoher Qualität gefertigt werden.
Intelligente Schichten für „denkende Oberflächen”︁
Authors: Bräuer Günter , Bandorf Ralf , Biehl Saskia , Dietz Andreas , Lüthje Holger , Vergöhel Michael 
Published: November 2006

AbstractDie Herstellung intelligenter Oberflächen nach dem Vorbild der Natur ist ein wichtiges Forschungsthema der nahen Zukunft. Bereits heute gibt es Beispiele für Beschichtungen, die in der Lage sind, entweder intrinsisch oder von außen gezielt gesteuert ihre Eigenschaften an Umweltbedingungen anzupassen. Dazu gehören z. B. Sonnenschutzbeschichtungen mit schaltbarer Transmission oder selbstreinigende Oberflächen auf der der Basis der Photokatalyse.Neuartige Schichten mit hervorragenden tribologischen Eigenschaften und sensorischen Fähigkeiten eröffnen neue Wege in der zukünftigen Gestaltung von Antriebselementen. Sie besitzen das Potential, den aktuellen Zustand einer mechanisch belasteten Oberfläche jederzeit kontrollieren und in geeigneter Weise beeinflussen zu können. Beispiele dafür sind piezoresistive amorphe Kohlenstoffschichten, die ausgeprägte kraftsensorische Eigenschaften bei gleichzeitig hoher Härte und niedrigen Reibungskoeffizienten besitzen. Die Einsatzmöglichkeiten solcher Dünnschichtsensoren sind außerordentlich vielfältig.
Cytostatic activity of syntheticO‐alkylglycerolipids
Authors: Brachwitz Hans , Langen Peter , Arndt Dieter , Fichtner Iduna 
Published: December 2006

AbstractA series of halogen‐containing alkylglycerolipid analogs has been checked for their cytostatic activity both in vitro and in vivo. The compounds included alkyldeoxyhaloglycerols (I), alkyldeoxyhaloglycerophosphocholines (II), and alkyldeoxyhaloglycerophosphoric acids and alkyl esters (III). While compounds I and III were moderately active, compounds II were found to have a strong inhibitory effect on the proliferation of Ehrlich ascites tumor cells in vitro. Cell growth inhibition of 50% or more was found mainly in the late S‐ or G2‐phase of the cell cycle as revealed by flow cytometry. Alkyl lysophospholipid analogs II and cholesterol form liposomes with high encapsulation efficiency and low permeability for entrapped substances. Compounds II were active against Lewis lung carcinoma in mice when applied in free form or as liposomes.
Distribution and metabolism of hexadecylphosphocholine in mice
Authors: Breiser A. , Kim D. ‐J. , Fleer E. A. M. , Damenz W. , Drube A. , Berger M. , Nagel G. A. , Eibl H. , Unger C. 
Published: December 2006

AbstractDistribution and metabolic fate of radiolabeled hexadecylphosphocholine (He‐PC) has been studied in mice. It is demonstrated that He‐PC is well‐absorbed from the intestinal tract, intravenous (IV) and oral administration lead to similar distributions throughout the body, the highest accumulation of radioactivity occurs in liver, lung and kidney, and the metabolic products are radioactive choline, phosphocholine and 1,2‐diacylphosphatidylcholine. The occurrence of these metabolites indicates that phospholipases C and D may be involved in He‐PC breakdown.
Alkyl phosphocholines: Toxicity and anticancer properties
Authors: Muschiol C. , Berger M. R. , Schuler B. , Scherf H. R. , Garzon F. T. , Zeller W. J. , Unger C. , Eibl H. J. , Schmähl D. 
Published: December 2006

AbstractThe study reports on the investigation of acute and subacute toxicity and on antineoplastic activity of hexadecylphosphocholine (HPC), the first compound of a new class of antineoplastic chemotherapeutics. In rats, the LD50 of HPC was 606 μmol/kg; the maximum tolerable dose over four weeks was 39 μmol/kg. Symptoms of toxicity were enteritis, spider cell activation in the liver, hemosiderosis in the spleen and reversible transaminase increase. The best therapeutic effect was observed on methylnitrosourea (MNU)‐induced mammary carcinoma in the rat. Two transplantable mammary carcinomas in the rat and autochthonous benzo(a)pyrene‐induced sarcomas exhibited low‐grade sensitivity to HPC. The MXT mammary carcinoma of the mouse, the Walker 256 carcinosarcoma of the rat, and autochthonous acetoxymethylmethylnitrosamine‐induced colonic tumors of the rat were not chemosensitive to HPC.
Modulation of chemical carcinogenesis in rats by alkyl lysophospholipids
Authors: Berger Martin R. , Schmähl Dietrich 
Published: December 2006

AbstractThe influence of 1‐O‐octadecyl‐2‐O‐methyl‐rac‐glycero‐3‐phosphocholine (ET‐18‐OCH3) and 1‐hexadecylmercapto‐2‐methoxymethyl‐rac‐propyl‐3‐phosphocholine (TLP, BM41.440) on methylnitrosourea (MNU)‐induced rat mammary carcinomas and of ET‐18‐OCH3 on 7,12‐dimethylbenzanthracene (DMBA)‐induced leukemias was investigated. Both agents effectively delayed MNU‐induced mammary tumor formation at high, cytotoxic dosages but TLP had no influence at low “immunomodulatory” doses. ET‐18‐OCH3 also significantly protected against leukemia development in DMBA‐treated Long‐Evans rats.
In vitro and in vivo cytotoxicity of alkyl lysophospholipid ET‐18‐OCH3 and thioether lipid BM 41.440
Authors: Leder G. H. , Fiebig H. H. , Wallbrecher E. , Winterhalter B. R. , Löhr G. W. 
Published: December 2006

AbstractScreening for cytotoxicity in the clonogenic assay in human tumor xenografts and L1210 mouse leukemia revealed comparable dose‐dependent effects of the alkyl lysophospholipid ET‐18‐OCH3 and the thioether lipid BM 41.440. The efficacy in human tumors only was marginal at low doses. In vivo tests of both agents were carried out in nude mice bearing two of the tumors that proved most sensitive in vitro and in mice inoculated with L1210 leukemia. Only small effects on the growth of the human tumors and no effects on L1210 leukemia were observed. In view of clinical rules for definition of remission, no convincing antitumor effects were obtained.
Late presentation of medium‐chain acyl‐CoA dehydrogenase deficiency
Authors: Mayell S. J. , Edwards L. , Reynolds F. E. , Chakrapani A. B. 
Published: December 2006

SummaryMedium‐chain acyl‐CoA dehydrogenase (MCAD) deficiency is the commonest disorder of fatty acid metabolism, with a high incidence of morbidity and mortality at presentation. We report a 16 year old girl with first presentation of MCAD deficiency following an alcoholic binge and subsequent period of starvation. Presentation was as acute encephalopathy progressing to coma. Renal, cardiac and hepatic failures were managed with intensive supportive care including mechanical ventilation, inotropic support, blood products and renal replacement therapy. Diagnosis of MCAD deficiency was confirmed on day 6. The patient was discharged from hospital on day 20 with a mild proximal myopathy, which subsequently resolved. The diagnosis of MCAD deficiency requires a high index of suspicion at all ages. Precipitating factors in later life may include alcohol.