bluuebunny/crossref_metadata_2025_split huggingface dataset:
Paste extrusion control and its influence on pore size properties of PTFE membranes
Authors: Huang Radium , Hsu Ping‐Shun , Kuo Chun‐Yin , Chung Chen Shia , Lai Juin‐Yih , Lee L. James 
Published: February 2008

AbstractPolytetrafluoroethylene (PTFE) is a remarkable membrane material. Owing to its high‐melting point, PTFE fine powder cannot be processed using conventional melting processing methods. Instead, techniques such as paste extrusion, rolling, and sintering have to be employed. Each processing step has an important influence on the final pore size quality within the membrane. In this paper, a PID controller (proportional‐integral‐derivative controller) was used to improve the properties of PTFE paste during the extrusion process and the quality of the PTFE membrane. A range of lubricant content (18, 20, and 22 wt%) was used to monitor the pressure drop at different extrusion speeds (0.5, 1, and 2 mm/s) and reduction ratios (RR = 26.47, 47.06, 80.06). It was found that a higher lubricant content and a higher reduction ratio resulted in a lower pressure drop. It was also found that a higher stretching temperature tends to result in larger pore size and broader pore size distribution at the same stretching rate. At a monitored and controlled constant low‐extrusion speed, the porosity of PTFE membrane was increased from 38% to 55% and the mean pore size was decreased from 0.22 to 0.15 μm because of less migration and more uniform distribution of lubricant during extrusion. Properties and the associated property uniformity of the PTFE extrudate affect the subsequent membrane‐forming process and the final pore size and size distribution significantly. © 2008 Wiley Periodicals, Inc. Adv Polym Techn 26:163–172, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20099
Anomalous rheological response for binary blends of linear polyethylene and long‐chain branched polyethylene
Authors: Mieda Naoya , Yamaguchi Masayuki 
Published: February 2008

AbstractThe rheological properties are studied for binary blends composed of a low‐density polyethylene (LDPE) and a linear polyethylene. It is found that some blends exhibit higher oscillatory shear moduli and drawdown force than the individual pure components, demonstrating that relaxation mechanism with longer characteristic time appears in the blend. The anomalous rheological behavior is detected more clearly for the blends with autoclave‐LDPE than those with tubular‐LDPE. Furthermore, the number of short‐chain branches in a linear polyethylene has no influence on the rheological properties of the blends, suggesting that the phase separation will not be responsible for the anomalous behavior. It is also found that blends of autoclave‐LDPE and tubular‐LDPE show no synergetic effect. © 2008 Wiley Periodicals, Inc. Adv Polym Techn 26:173–181, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20100
Lipoprotein‐associated phospholipase A2 and risk of venous thrombosis in older adults
Authors: Olson Nels , O'Meara Ellen S. , Jenny Nancy S. , Folsom Aaron R. , Bovill Edwin G. , Furberg Curt D. , Heckbert Susan R. , Psaty Bruce M. , Cushman Mary 
Published: February 2008

AbstractLipoprotein‐associated phospholipase A2 (Lp‐PLA2) is an enzyme involved in inflammation and platelet function. Inherited deficiency and elevated levels are associated with atherosclerosis. Given potential common etiologies of atherosclerosis and venous thrombosis (VT), we hypothesized that low and high Lp‐PLA2 would be associated with VT risk. Lp‐PLA2 mass and activity were measured in baseline samples of Cardiovascular Health Study participants (5,888 men and women age ≥65), excluding 354 reporting pre‐baseline VT. The study endpoint was VT unrelated to cancer after 11.6 years follow‐up. Hazard ratios were estimated using Cox proportional hazard models, adjusting for age, race, sex, and body‐mass index. With 129 cases of VT, there was no association of Lp‐PLA2 activity with risk. Adjusted hazard ratios were 1.19 (CI 0.62, 2.29) and 0.87 (CI 0.43, 1.76) for the lowest and highest decile, respectively, compared to the 10–25th percentile. Corresponding hazard ratios for Lp‐PLA2 mass were 1.63 (CI 0.79, 3.34) and 1.33 (CI 0.61, 2.87). Results were robust to several definitions of low or high Lp‐PLA2. While the association of Lp‐PLA2 levels with arterial disease events implies a role for this enzyme in atherogenesis, our findings suggest that it is not prothrombotic. Am. J. Hematol. 2008. © 2008 Wiley‐Liss, Inc.
Cancer incidence among male Massachusetts firefighters, 1987–2003
Authors: Kang Dongmug , Davis Letitia K. , Hunt Phillip , Kriebel David 
Published: February 2008

AbstractBackgroundFirefighters are known to be exposed to recognized or probable carcinogens. Previous studies have found elevated risks of several types of cancers in firefighters.MethodsStandardized morbidity odds ratio (SMORs) were used to evaluate the cancer risk in white, male firefighters compared to police and all other occupations in the Massachusetts Cancer Registry from 1986 to 2003. Firefighters and police were identified by text search of the usual occupation field. All other occupations included cases with identifiable usual occupations not police or firefighter. Control cancers were those not associated with firefighters in previous studies.ResultsRisks were moderately elevated among firefighters for colon cancer (SMOR = 1.36, 95% CI: 1.04–1.79), and brain cancer (SMOR = 1.90, 95% CI: 1.10–3.26). Weaker evidence of increased risk was observed for bladder cancer (SMOR = 1.22, 95% CI: 0.89–1.69), kidney cancer (SMOR = 1.34, 95% CI: 0.90–2.01), and Hodgkin's lymphoma (SMOR = 1.81, 95% CI: 0.72–4.53).ConclusionsThese findings are compatible with previous reports, adding to the evidence that firefighters are at increased risk of a number of types of cancer. Am. J. Ind. Med. 51:329–335, 2008. © 2008 Wiley‐Liss, Inc.
Molecular and clinical description of a girl with a 46,X,t(Y;4)(q11.2;p16)/45,X,der(4)t(Y;4)(q11.2;p16) karyotype and a small cryptic 4p subtelomeric deletion
Authors: Zahed Laila , Sismani Carolina , Ioannides M. , Saleh Monzer , Koumbaris G. , Kenj Mazen , Abdallah Amal , Ayyache Maya , Patsalis Philippos 
Published: February 2008

AbstractWe report on a 13‐year‐old female with short stature, minimal axillary and pubic hair, no breast development, absence of uterus and ovaries, with the following karyotype on lymphocyte cultures: 46,X,t(Y;4)(q11.2;p16)[40]/45,X,der(4)t(Y;4)(q11.2;p16)[10]. Loss of the small derivative Y chromosome in 20% of the cells was also confirmed in skin fibroblast cultures. FISH analyses using Y centromere, SRY, subtelomere XpYp/XqYq, Y and 4 painting probes, confirmed the cytogenetic findings. High‐resolution STS analyses using 40 markers covering the Y chromosome did not identify any deletion on the Y. However, de novo absence of the 4p subtelomeric region was noted by FISH, although this deletion was not revealed by Array‐CGH at 1 Mb resolution, the last array clone being 0.35 or 1 Mb distal to the 4p FISH probe. The female phenotype of this patient must be due to the loss of the derivative Y chromosomes in some of her cells, especially the gonads, while the 4p subtelomeric deletion does not seem to contribute to her phenotype. © 2008 Wiley‐Liss, Inc.
Adenosine A2A receptor antagonist istradefylline (KW‐6002) reduces “off” time in Parkinson's disease: A double‐blind, randomized, multicenter clinical trial (6002‐US‐005)
Authors: LeWitt Peter A. , Guttman M. , Tetrud James W. , Tuite Paul J. , Mori Akihisa , Chaikin Philip , Sussman Neil M. ,   6002‐US‐005 Study Group
Published: February 2008

AbstractObjectiveBased on new understanding of nondopaminergic pathways involved in Parkinson's disease (PD) pathophysiology, a selective adenosine A2A receptor antagonist, istradefylline, shows promise for the treatment of PD.MethodsIstradefylline (40mg/day) was studied in levodopa‐treated PD subjects experiencing prominent wearing‐off motor fluctuations. At 23 North American sites, 196 subjects were randomized in a double‐blind, 12‐week outpatient clinical trial of istradefylline (114 completing the trial) or placebo (58 completing the trial). The primary efficacy measure was change from baseline to end point in the percentage of daily awake “off” time, recorded by subjects using a patient PD diary. Secondary end points evaluated “on” time (including “on time with dyskinesia”), the Unified Parkinson's Disease Rating Scale, and a Clinical Global Impression–Improvement of Illness score. Clinical laboratory, electrocardiograms, vital signs, and adverse event monitoring comprised the safety monitoring.ResultsAfter randomization, approximately 88% of subjects completed the double‐blind period. Compared with baseline, the decrease of daily awake “off” time for istradefylline was a mean (± standard deviation) of −10.8 ± 16.6% (95% confidence interval, −13.46 to −7.52) and for placebo, −4.0 ± 15.7% (95% confidence interval, −7.73–0.31; p = 0.007 using two‐way analysis of variance). This effect corresponded to changes from baseline in total daily awake “off” time of −1.8 ± 2.8 hours for istradefylline and −0.6 ± 2.7 hours for placebo (p = 0.005). Treatment‐emergent adverse effects with istradefylline were generally mild.InterpretationIstradefylline was safe, well tolerated, and offered a clinically meaningful reduction in “off” time without increased troublesome dyskinesia. Ann Neurol 2008
Varicella‐zoster virus in cerebrospinal fluid at relapses of multiple sclerosis
Authors: Sotelo Julio , Martínez‐Palomo Adolfo , Ordoñez Graciela , Pineda Benjamin 
Published: February 2008

AbstractObjectiveRecent studies in peripheral blood mononuclear cells (PBMCs) have indicated that exacerbations of multiple sclerosis (MS) could be associated with the reactivation of latent varicella‐zoster virus (VZV).MethodsUltrastructural observations for viral particles were made by electron microscopy in cerebrospinal fluid (CSF) from 15 MS patients during relapse, 19 MS patients during remission, and 28 control subjects. Initial findings were reproduced in a confirmation cohort. In addition, DNA from VZV was quantified by real‐time polymerase chain reaction in PBMCs and CSF from a large number of MS patients (n = 78).ResultsWe found by electron microscopy the presence of abundant viral particles identical to VZV in CSF obtained from MS patients within the first few days of an acute relapse. In contrast, viral particles were not seen in CSF samples from MS patients in remission or from neurological control subjects. Also, DNA from VZV was present in CSF and in PBMCs during relapse, disappearing in most patients during remission. The mean viral load was 542 times greater in CSF at relapse than in CSF at remission and 328 times greater in CSF at relapse than in PBMCs at relapse.InterpretationThe ultrastructural finding of viral particles identical to VZV, together with the simultaneous presence of large quantities of DNA from VZV in the subarachnoid space, almost restricted to the periods of exacerbation, as well as its steady diminution and eventual disappearance from clinical relapse to clinical remission are surprising and constitute the strongest evidence to support the participation of VZV in the pathogenesis of MS. Ann Neurol 2008
Neurohospitalists: An emerging model for inpatient neurological care
Authors: Josephson S. Andrew , Engstrom John W. , Wachter Robert M. 
Published: February 2008

AbstractOver the past decade, the hospitalist model has become a dominant system for the delivery of general adult and pediatric inpatient care. Similar forces, including national mandates to improve safety and quality and intense pressure to safely reduce length of hospital stays, that led to the remarkable growth of hospitalist medicine are now exerting pressure on neurologists. A neurohospitalist model, in which inpatient neurology specialists deliver high‐quality and efficient care to neurology patients, is emerging to meet these challenges. Benefits of this system may include more frequent, timely neurology consultations in the hospital and emergency department, as well as improved quality of inpatient neurological education for residents and medical students. Challenges will involve defining the relationship of neurohospitalists with primary stroke centers, the economic feasibility of such neurohospitalist systems, and how to train members of this new field. A neurohospitalist model of care is an emerging idea in neurology that would overcome many regulatory, educational, and economic challenges facing neurologists; further research is needed to gauge the effects of this innovative approach. Ann Neurol 2008;63:135–140
Materialanwendungen für Salenstrukturen
Authors: Wezenberg Sander J. , Kleij Arjan W. 
Published: February 2008

AbstractSalene zählen zu den meistuntersuchten Liganden in der Chemie. Sie werden hauptsächlich in der homogenen Katalyse angewendet, wo sie dazu beitragen, unser Wissen über umweltfreundliche und kostengünstige chemische und/oder pharmazeutische Prozesse zu vertiefen. In letzter Zeit hat sich das Interesse auf dem Gebiet der Salenchemie auf verschiedene andere Anwendungen verlagert, in denen die immensen Einsatzmöglichkeiten der Salenstrukturen als molekulare Bausteine im Vordergrund stehen. In diesem Kurzaufsatz stellen wir die neuesten Forschungsarbeiten vor, die sich mit dem Einbau von Salenstrukturen in neue Materialien und hochentwickelte Katalysatoren beschäftigen.
Tailored functionalization of low‐density polyethylene surfaces
Authors: Goddard J. M. , Hotchkiss J. H. 
Published: February 2008

AbstractSurface‐functionalization chemistries were optimized to tailor the surface chemistry of polyethylene, and this made covalent attachment of bioactive molecules possible. This concept has relevance in biomaterials, biosensors, textiles, and active food‐packaging applications. Clean polyethylene films were subjected to chromic acid oxidation to introduce carboxylic acids. A range of functional groups, including amine, aldehyde, thiol, and hydroxyl, were then introduced to the surface of the oxidized films with functionalized crosslinking agents and covalent bioconjugation chemistries. The quantity of functional groups was further increased by subsequent grafting of polyfunctional agents such as polyethylenimine and poly(acrylic acid). The number and type of functional groups were quantified by contact‐angle, dye‐assay, attenuated total reflectance/Fourier transform infrared, and X‐ray photoelectron spectroscopy analyses. We optimized chemistries to introduce a variety of functional groups to the surface of low‐density polyethylene in numbers ranging from several picomoles per centimeter squared to tens of nanomoles per centimeter squared. A range of bioactive compounds, including antimicrobials, antibodies, oligonucleotides, cell precursors, drugs, peptides, enzymes, and synthetic biomimetic agents, can be covalently bound to these functional groups in the development of nonmigratory biofunctionalized polymers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Nonequilibrium nanoblend membranes for the pervaporation of benzene/cyclohexane mixtures
Authors: Okeowo Oluwasijibomi , Nam Sang Yong , Dorgan John R. 
Published: February 2008

AbstractImmiscible blends of polymers were cast from solution, and the rate of evaporation was controlled relative to the rate of phase separation to produce different morphologies; upon crosslinking, stable nonequilibrium nanoblends were realized. This process of forced assembly produced useful membrane materials that could be designed for solubility selectivity with the group contribution methodology. Crosslinked ternary blends of nitrile butadiene rubber (NBR), poly(methyl methacrylate) (PMMA), and a tercopolymer of ethylene oxide/epichlorohydrin/allyl glycidyl ether (Hydrin) were examined for use in the separation of benzene from cyclohexane by pervaporation. For a 50 : 50 wt % benzene/cyclohexane feed, blend 811 (containing 80 wt % NBR, 10 wt % Hydrin, and 10 wt % PMMA) gave a separation factor of 7.3 and a normalized flux of 28 kg μm/m2 h; such a performance is unmatched in the literature, with the flux being very high for the reported separation factor. Among the samples tested, the flux of the membrane increased as the amount of NBR in the ternary blend decreased; however, the separation factor was not largely affected. Blended samples showed no sign of deformation after 48 h at the operating temperature as compared to pure NBR, which did show evidence of creep. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
General and more precise relationships between molecular weight, blend ratio, and melt index of binary polyethylene blends
Authors: Ghasemi S. M. , Sadeghi G. Mir Mohamad 
Published: February 2008

AbstractSimpler, cheaper, and fast methods to characterize material properties are important in industrial plants. One of these properties is molecular weight which is measured generally by size exclusion chromatography, an expensive method and also limited for polyolefins which have few solvents. Melt flow index (MFI) measurement is simple, cheap, and rapid that could be a considerable method to estimate of polymers. In this work, mathematical correlation between MI* (a new defined MFI), first melt dropping of blend (t1), weight fraction (wi) and
in binary polyethylene blends, PE/PE wax, has been investigated by using a new device. Results show that relationships MI* and t1 with wi of the blended materials follow a modified Arrhenius equation (Wong equation) and also new non‐Arrhenius equations for prediction of MI of blends have been investigated. We proposed a modified molecular weight () for Bremner and Rudin's equation (Bremner et al., J Appl Polym Sci 1990, 41, 1617), which is used in 1/MI* and t1 correlations with molecular weight of polymer. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Measurement of the condensation temperature of nanosilica powder organically modified by a silane coupling agent and its effect evaluation
Authors: Liu Xiao , Zhao Suhe 
Published: February 2008

AbstractThe proper condensation temperatures of nanosilica powder modified by silane coupling agents such as 3‐methacryloxypropyl trimethoxy silane (MEMO), [3‐(2‐aminoethyl)aminopropyl] trimethoxy silane (AMMO), and bis[3‐(triethoxysilyl)propyl] disulfide (TESPD) were measured with Fourier transform infrared. Moreover, the structure and properties of solution‐polymerized styrene–butadiene rubber (SSBR) filled with nanosilica powder that was organically modified by the three silane coupling agents at different temperatures were investigated. The results showed that the proper condensation temperatures of nanosilica powder modified by MEMO, AMMO, and TESPD were about 80, 80, and 100°C, respectively. Compared with SSBR filled with silica powder, SSBR filled with silica powder modified by a silane coupling agent exhibited not only better filler‐dispersion and mechanical properties but also lower internal friction loss in a selected range of strains. Furthermore, when the organic modification was carried out at the proper condensation temperature, the improvement of the modification effect became more obvious. Among these silane coupling agents, AMMO presented the most remarkable modification effect for nanosilica. The mechanism of modification for silica powder and its enhancement of the properties of SSBR were examined. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis and characterization of new optically active segmented poly(amide imide urethane)s based on different diacids via an isocyanate route
Authors: Mallakpour Shadpour , Khani Marziyeh , Rafiemanzelat Fatemeh 
Published: February 2008

AbstractA new class of optically active poly(amide imide urethane)s (PAIUs) was synthesized via a two‐step diisocyanate route. In the first step, 4,4′‐methylenebis(phenyl isocyanate) (MDI) was reacted with different diacids to produce an isocyanate‐terminated oligo(amide imide). The chain extension of the previous hard segment with poly (ethylene glycol) diols with a molecular weight of 400 was the second step for furnishing a series of new PAIUs. N‐Trimellitylimido‐L‐leucine was used as a diacid monomer for polycondensation reactions. Polymerization reactions were performed without any catalysts or with pyridine or dibutyltin dilaurate as a catalyst. The optimized reaction conditions were used for the reaction of N‐trimellitylimido‐L‐isoleucine, N‐trimellitylimido‐L‐methionine, N‐trimellitylimido‐S‐valine, and N‐trimellitylimido‐L‐phenylalanine as diacid monomers with MDI. The resulting multiblock copolymers had inherent viscosities of 0.25–0.78 dL/g. These multiblock copolymers were optically active, thermally stable, and soluble in amide‐type solvents. All these polymers were fully characterized with Fourier transform infrared spectroscopy, 1H‐NMR and ultraviolet–visible spectroscopy, specific rotation measurements, and thermal analyses. Some structural characteristics and physical properties of these new optically active PAIUs were examined. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Study on the microstructure of EPDM/NBR blend by positron annihilation spectroscopy
Authors: Mostafa N. 
Published: February 2008

AbstractPositron annihilation lifetime and Doppler broadening of annihilation radiation techniques were employed to investigate the relationship between free‐volume hole properties and miscibility of ethylene propylene diene monomer (EPDM)/acrylonitrile butadiene rubber (NBR) blends. It has been found that there were positive and negative deviations in free‐volume hole size (τ3) and concentration (I3) as well as S‐parameter from linear relationship of initial polymers indicating the immiscibility of the blend. The broadening in free‐volume hole distribution by increasing NBR content in EPDM/NBR blend confirm the results obtained by finite term analysis. From the filling effect of silica on free‐volume properties of EPDM/NBR (75/25) blend, it has been found that the addition of silica up to 50 phr is the most promising concentration for electrical application. Furthermore, correlations were established between free‐volume hole size and fraction combined with the results of electrical (dielectric constant and dielectric loss) and mechanical (stress at yield and strain at yield) properties. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Hygrothermische Wirkungen von Raum‐ und Außenoberflächen
Authors: Stopp Horst , Strangfeld Peter , Toepel Torsten 
Published: February 2008

AbstractWährend bislang der Schutz einer Baukonstruktion vor Außen‐ und Innenklimabelastungen im Vordergrund bauphysikalischer Überlegungen stand, werden heute zunehmend passiv und aktiv wirksame Prozesse der Bauwerkshülle und deren Einflüsse auf das äußere und innere Umfeld für Bauherren und Nutzer interessant. Der vorliegende Beitrag befasst sich mit den hygrothermischen Vorgängen auf Außen‐ und Innenoberflächen von Gebäuden, insbesondere von Wänden und ihren Wirkungen auf den Transmissionswärmeverlust und die relative Raumluftfeuchte in Abhängigkeit der außen‐ und innenklimatischen Randbedingungen sowie ggf. vorhandener Wärmequellen zur Vermeidung mikrobiologischen Bewuchses. Untersuchungsmethoden und ‐ergebnisse zur Beurteilung der langwelligen Abstrahlung von Bauteiloberflächen sowie Ergebnisse zum Einfluss sorptiv wirksamer Raumoberflächen auf das Raumklima von Archivräumen werden mitgeteilt.
Auf dem Weg zu einer CO2‐freien Wärmeversorgung – Probleme mit den Wegweisern?
Authors: Rabenstein Dietrich 
Published: February 2008

AbstractEs wird geprüft, wie gut sich die geplante EnEV 2009, die Hamburgische Klimaschutzverordnung sowie die Erneuerbare‐Energien‐Wärmegesetze auf Bundesebene und in Baden‐Württemberg dazu eignen, die beabsichtigten Klimaschutzziele zu erreichen. Ein sparsamer Umgang mit erneuerbarer Wärme ist bisher nicht ausreichend abgesichert. Ersatzmaßnahmen sind ökonomisch noch attraktiver als Solarpflichten. CO2‐Emissions‐Grenzen wären vorteilhafter als Primärenergiebedarfs‐Grenzen. Eine Zusammenfassung der Energieeinsparverordnung und des Erneuerbare‐Energien‐Wärmegesetzes wird vorgeschlagen.