bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanical properties and in vitro degradation of bioresorbable fibers and expandable fiber‐based stents
Authors: Zilberman Meital , Nelson Kevin D. , Eberhart Robert C. 
Published: June 2005

AbstractBioresorbable polymeric support devices (stents) are being developed in order to improve the biocompatibility and drug reservoir capacity of metal stents, as well as to offer a temporary alternative to permanent metallic stents. These temporary devices may be utilized for coronary, urethral, tracheal, and other applications. The present study focuses on the mechanical properties of bioresorbable fibers as well as stents developed from these fibers. Fibers made of poly(L‐lactide) (PLLA), polydioxanone (PDS), and poly(glycolide‐co‐ϵ‐caprolactone) (PGACL) were studied in vitro. These fibers combine a relatively high initial strength and modulus together with sufficient ductility and flexibility, and were therefore chosen for use in stents. The effect of degradation on the tensile mechanical properties and morphology of these fibers was examined. The expandable stents developed from these fibers demonstrated excellent initial radial compression strength. The PLLA stents exhibited excellent in vitro degradation resistance and can therefore support body conduits such as blood vessels for prolonged periods of time. PDS and PGACL stents can afford good support for 5 and 2 weeks, respectively, and can therefore be utilized for short‐term applications. The degradation resistance of the stents correlates with the profile of mechanical property deterioration of the corresponding bioresorbable fibers. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2005
BK‐induced cytosolic phospholipase A2 expression via sequential PKC‐δ, p42/p44 MAPK, and NF‐κB activation in rat brain astrocytes
Authors: Hsieh Hsi‐Lung , Wu Cheng‐Ying , Hwang Tsong‐Long , Yen Mao‐Hsiung , Parker Peter , Yang Chuen‐Mao 
Published: June 2005

AbstractBradykinin (BK), an inflammatory mediator, has been shown to induce cytosolic phospholipase A2 (cPLA2) expression implicating in inflammatory responses in various cell types. However, the detailed mechanisms underlying BK‐induced cPLA2 expression in astrocytes remain unclear. RT‐PCR and Western blotting analysis showed that BK induced the expression of cPLA2 mRNA and protein, which was inhibited by Hoe140, suggesting the involvement of B2 BK receptors, confirmed by immunofluorescence staining using anti‐B2 BK receptor antibody. BK‐induced cPLA2 expression and phosphorylation of p42/p44 MAPK was attenuated by PD98059, indicating the involvement of MEK1/2‐p42/p44 MAPK in these responses. BK‐induced cPLA2 expression might be due to the translocation of NF‐κB into nucleus which was inhibited by Hoe140, helenalin, and PD98059, implying the involvement of NF‐κB. Moreover, BK‐induced cPLA2 expression was attenuated by rottlerin, suggesting that PKC‐δ might be involved in these responses. This hypothesis was supported by the transfection with a dominant negative plasmid of PKC‐δ significantly attenuated BK‐induced response. In addition, BK‐stimulated translocation of PKC‐δ from cytosol to membrane fraction was inhibited by rottlerin but not by PD98059, indicating that PKC‐δ might be an upstream component of p42/p44 MAPK. Accordingly, BK‐induced phosphorylation of p42/p44 MAPK was attenuated by rottlerin but not by helenalin. These results suggest that in RBA‐1 cells, BK‐induced cPLA2 expression was sequentially mediated through activation of PKC‐δ, p42/p44 MAPK, and NF‐κB. Understanding the regulation of cPLA2 expression induced by BK in astrocytes might provide a new therapeutic strategy of brain injury and inflammatory diseases. © 2005 Wiley‐Liss, Inc.
Binary and Ternary mLLDPE Blends: Tailoring Their Properties Using Complex Viscosity Measurements
Authors: Flores Miguel Angel , Alicante Raquel , Pérez Ruth , Rojo Elena , Fernández Mercedes , Santamaría Anton 
Published: June 2005

AbstractSummary: Metallocene‐catalysed linear low density polyethylenes (mLLDPEs) of different molecular weights are mixed with a base mLLDPE to obtain a pre‐determined grade and a suitable extrusion processability. Complex viscosity results are revealed as a very suitable tool to tailor the properties of the prepared binary and ternary blends. The investigated blends show symptoms of miscibility like time‐temperature superposition and observance of Cox‐Merz rule. This allows to evaluate the molecular weight distribution, supplying also practical data related to the polyethylene grade and ‘sharkskin’ instability. The complex viscosity curve of a model sample that would have both, a suitable grade and processability, is created; blends are prepared to match the model curve. The blend with a low molecular weight mLLDPE shows a parallel shift of the complex viscosity to lower values (molecular weight distribution is not broadened), postponing sharkskin, but changing the polymer grade. Satisfactory results are neither obtained with blends of a high molecular weight mLLDPE. Best results are obtained with ternary blends, which combine the modifications provided by low and high molecular weight mLLDPEs, approaching the complex viscosity and molecular weight distribution of the model.Complex viscosity results of PR‐207 (– —), PR‐209 (···) and PR‐210 (– –) ternary blends, as compared with those of base samples PR‐201 (symbols) and the model (line).magnified imageComplex viscosity results of PR‐207 (– —), PR‐209 (···) and PR‐210 (– –) ternary blends, as compared with those of base samples PR‐201 (symbols) and the model (line).
Preparation of Poly(ethylene‐octene) Elastomer/Clay/Wood Flour Nanocomposites by a Melting Method
Authors: Liao Hsin‐Tzu , Wu Chin‐San 
Published: June 2005

AbstractSummary: The new nanocomposites consisting of metallocene poly(ethylene‐octene) (POE), silicate clay and wood flour (WF) were prepared by means of a melt blending method. In addition, maleic anhydride grafted poly(ethylene‐octene) (POE‐g‐MAH) was studied as an alternative to POE. The samples were characterized by XRD, FT‐IR spectroscopy, DSC, TGA, SEM, and mechanical testing. Based on the consideration of thermal and mechanical properties, it was found that the clay content of 11 wt.‐% was optimal for the preparation of POE‐g‐MAH/clay nanocomposites. The POE‐g‐MAH/clay/WF hybrid could obviously improve the mechanical properties of POE‐g‐MAH/WF hybrid since the former had the smaller WF phase size (being always less than 1.5 µm), the SiOC bond and the nanoscale dispersion of silicate layers in the polymer matrix. The biodegradation studies showed that the mass of hybrids reduced by about the content of WF. The new POE‐g‐MAH/clay/WF nanocomposites produced from our laboratory can provide a plateau tensile strength at break when the WF content was up to 50 wt.‐%.
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Heat capacity of poly(vinyl methyl ether)
Authors: Pyda M. , Van Durme K. , Wunderlich B. , Van Mele B. 
Published: June 2005

AbstractThe heat capacity of poly(vinyl methyl ether) (PVME) has been measured using adiabatic calorimetry and temperature‐modulated differential scanning calorimetry (TMDSC). The heat capacity of the solid and liquid states of amorphous PVME is reported from 5 to 360 K. The amorphous PVME has a glass transition at 248 K (−25 °C). Below the glass transition, the low‐temperature, experimental heat capacity of solid PVME is linked to the vibrational molecular motion. It can be approximated by a group vibration spectrum and a skeletal vibration spectrum. The skeletal vibrations were described by a general Tarasov equation with three Debye temperatures Θ1 = 647 K, Θ2 = Θ3 = 70 K, and nine skeletal modes. The calculated and experimental heat capacities agree to better than ±1.8% in the temperature range from 5 to 200 K. The experimental heat capacity of the liquid rubbery state of PVME is represented by Cp(liquid) = 72.36 + 0.136 T in J K−1 mol−1 and compared to estimated results from contributions of the same constituent groups of other polymers using the Advanced Thermal AnalysiS (ATHAS) Data Bank. The calculated solid and liquid heat capacities serve as baselines for the quantitative thermal analysis of amorphous PVME with different thermal histories. Also, knowing Cp of the solid and liquid, the integral thermodynamic functions of enthalpy, entropy, and free enthalpy of glassy and amorphous PVME are calculated with help of estimated parameters for the crystal. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2141–2153, 2005
Basic studies on gas solubility in natural rubber–cellulose composites
Authors: Reis Nunes Regina C. , López‐González Mar , Riande Evaristo 
Published: June 2005

AbstractThis work reports sorption processes of oxygen, carbon dioxide, methane, ethylene, and propylene in films of both vulcanized natural rubber and vulcanized rubber–regenerated cellulose composites. The curves representing the pressure dependence of the concentration of carbon dioxide in the composites clearly exhibit a slight concavity with respect to the abscissa axis as a result of adsorption processes taking place in Langmuir sites located in the glassy cellulose component. Adsorption processes are also detected in the sorption curves of ethylene at low pressures. The concavity with respect to the ordinate axis of the curve concentration of propylene versus pressure at high pressure is pretty well described by the Flory‐Huggins formalism. The solubilities of the other gases mainly obey Henry's behavior, adsorption processes in the glassy component being in most cases negligible. Values of the interaction χ parameter for gas–natural rubber and gas–natural rubber composites are obtained from the comparison of the experimental solubility coefficients with those predicted by the Flory‐Huggins theory. The theory suggests that Henry's constant is a linear function of the boiling temperature of the gases. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2131–2140, 2005
The current status of LNG facility standards and regulations
Authors: Casada Myron L. , Nordin Donald C. 
Published: June 2005

AbstractWith the large number of proposed liquefied natural gas (LNG) facilities in the United States (and worldwide), many new technical personnel are becoming involved in applying and interpreting LNG standards and regulations. Also, opponents of the new LNG developments are questioning whether existing safety and security requirements are adequate. In this paper, we will begin with an overview of existing standards and regulations pertinent to LNG facilities (for both onshore and offshore applications). That discussion will include documents from the National Fire Protection Association, the European Committee for Standardization, the Department of Transportation, and the United States Coast Guard. For offshore facilities, it will discuss the guidelines from some of the international classification societies. This paper will outline what is addressed (and what is not addressed) by these standards and will then focus on and discuss the issues with those requirements and the changes that are currently under consideration by the standards organizations and federal regulators. This paper finishes with some specific recommendations for consideration by LNG facility developers. © 2005 American Institute of Chemical Engineers Process Saf Prog, 2005
Construction and utilisation of planar graphs of two series of IPR fullerenes through the use of threefold rotational symmetry
Authors: Mandal Bholanath , Datta Kakali , Banerjee Manas , Mukherjee Asok K. 
Published: June 2005

AbstractThreefold rotational symmetry has been used to develop an algorithm for the construction of planar graphs of IPR fullerenes and to factorize their characteristic polynomials. Two series of fullerenes of the formula C60+12n and C60+18n have thus been obtained. The algorithm has been shown to be useful for predicting the nature of variation of the point groups of the fullerenes with increased n, for counting the number of 13C nuclear magnetic resonance (NMR) signals (along with their relative intensities), and also for obtaining a large part of their eigenspectra. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Determination of the natural abundance δ15N of nicotine and related alkaloids by gas chromatography/isotope ratio mass spectrometry
Authors: Molinié Roland , Ferchaud‐Roucher Véronique , Lebreton Jacques , Robins Richard J. 
Published: June 2005

AbstractA method is described by which the natural abundanceδ15N values of nicotine, analogues, and metabolites can be determined. The alkaloids are extracted from their biological matrix by solid‐phase extraction and analysis is conducted using isotope ratio mass spectrometry interfaced to gas chromatography. Repeatability and precision are sufficient to allow differences in theδ15N values of less than 1.0‰ to be satisfactorily measured, with a standard deviation routinely less than 0.5‰. The methodology has been tested by determining the changes in theδ15N values of nicotine,N‐methyl‐2‐phenylpyrrolidine and their respective demethylation products, nornicotine and 2‐phenylpyrrolidine, during biotransformation by cell suspension cultures ofNicotianaspecies. Sufficient precision and reproducibility were obtained to allow the kinetic isotope effects associated with the demethylation reaction to be calculated. Copyright © 2005 John Wiley & Sons, Ltd.
Determination of the geographical origin of green coffee by principal component analysis of carbon, nitrogen and boron stable isotope ratios
Authors: Serra Francesca , Guillou Claude G. , Reniero Fabiano , Ballarin Luciano , Cantagallo Maria I. , Wieser Michael , Iyer Sundaram S. , Héberger Károly , Vanhaecke Frank 
Published: June 2005

AbstractIn this study we show that the continental origin of coffee can be inferred on the basis of coupling the isotope ratios of several elements determined in green beans. The combination of the isotopic fingerprints of carbon, nitrogen and boron, used as integrated proxies for environmental conditions and agricultural practices, allows discrimination among the three continental areas producing coffee (Africa, Asia and America). In these continents there are countries producing ‘specialty coffees’, highly rated on the market that are sometimes mislabeled further on along the export‐sale chain or mixed with cheaper coffees produced in other regions. By means of principal component analysis we were successful in identifying the continental origin of 88% of the samples analyzed. An intra‐continent discrimination has not been possible at this stage of the study, but is planned in future work. Nonetheless, the approach using stable isotope ratios seems quite promising, and future development of this research is also discussed. Copyright © 2005 John Wiley & Sons, Ltd.
High‐throughput biological sample analysis using on‐line turbulent flow extraction combined with monolithic column liquid chromatography/tandem mass spectrometry
Authors: Zhou Shaolian , Zhou Huiyu , Larson Mike , Miller Dennis L. , Mao Dunmin , Jiang Xiangyu , Naidong Weng 
Published: June 2005

AbstractA high‐throughput liquid chromatography/tandem mass spectrometry (LC/MS/MS) method, which combines on‐line sample extraction through turbulent flow chromatography with a monolithic column separation, has been developed for direct injection analysis of drugs and metabolites in human plasma samples. By coupling a monolithic column into the system as the analytical column, the method enables running ‘dual‐column’ extraction and chromatography at higher flow rates, thus significantly reducing the time required for the transfer and mixing of extracted fraction onto the separation column as well as the time for gradient separation. A strategy of assessing and reducing the matrix suppression effect on the on‐line extraction LC/MS/MS has also been discussed. Experiments for evaluating the resolution, peak shape, sensitivity, speed, and matrix effect were conducted with dextromethorphan and its metabolite dextrorphan as model compounds in human plasma matrix. It was demonstrated that the total run time for this assay with a baseline separation of two analytes is less than 1.5 min. Copyright © 2005 John Wiley & Sons, Ltd.
Rapid comparison of diacetylmorphine on banknotes by tandem mass spectrometry
Authors: Ebejer Karl A. , Brereton Richard G. , Carter James F. , Ollerton Samantha L. , Sleeman Richard 
Published: June 2005

AbstractA procedure is described for the determination of the distribution of the contamination of banknotes with controlled drugs using tandem mass spectrometry. The method is illustrated using diacetylmorphine, which is the major active component of heroin. A series of banknotes is introduced into the mass spectrometer and the intensities of two product ions (m/z 328 and 268) derived from the precursor protonated molecule (m/z 370) are recorded. A banknote is considered contaminated if it shows a significant peak for both product ions, and if the ratio of intensities of these two peaks falls within accepted limits. The distribution of diacetylmorphine on sterling banknotes taken from general circulation within the UK can be modelled by an arcsin (square root) transformation of the data or by a log transformation of the data with a higher proportion of contamination. The two models were found to be in close agreement, predicting an upper limit (at 99.9% confidence) of contamination on banknotes from general circulation between 9 and 10%. The percentage contamination in a case study was calculated and compared to the background distribution using the two models proposed. This comparison revealed that the contamination present in the case study was inconsistent with that present on banknotes in general circulation. Copyright © 2005 John Wiley & Sons, Ltd.
Poverty, violence and depression during pregnancy: a survey of mothers attending a public hospital in Brazil
Authors: LOVISI GIOVANNI MARCOS , LÓPEZ JOSÉ RAMON R. A. , COUTINHO EVANDRO SILVA FREIRE , PATEL VIKRAM 
Published: June 2005

Background. Depression in women is associated with social deprivation and violence. We describe the prevalence and risk factors for depression during pregnancy, in particular the association with poverty and violence, in a Brazilian setting.Method. A cross-sectional survey of women in the third trimester of pregnancy attending a public hospital maternity clinic from August 2003 to July 2004 in Rio de Janeiro. Participants were interviewed about their sociodemographic status, obstetric and medical conditions, substance use, stressful life events, and social support. Depression was diagnosed through the Composite International Diagnostic Interview (CIDI).Results. A total of 230 of 240 eligible women consented to participate. The 12-month prevalence of depression was 19·1% (95% CI 14·4–24·9). On multivariate analyses, having been educated beyond primary school was protective (OR 0·5, 95% CI 0·2–0·9). Risk factors were: being divorced or widowed (OR 4·9, 95% CI 1·3–18·3); a history of depression before pregnancy (OR 7·9, 95% CI 3·1–20·5); loss of an intimate relationship (OR 8·4, 95% CI 3·3–21·4), experienced financial difficulties (OR 6·6, 95% CI 2·5–17·2) and having been exposed to violence in the previous year (OR 4·2, 95% CI 1·5–11·8).Conclusions. Depression is common during pregnancy and is associated with indicators of socio-economic deprivation, violence and the loss of an intimate relationship, and with a previous history of depression. Psychosocial interventions and appropriate social policies need to be implemented in this population to reduce the burden of maternal depression.
Analysis of global mRNA expression in human skeletal muscle during recovery from endurance exercise
Authors: Mahoney D. J. , Parise G. , Melov S. , Safdar A. , Tarnopolsky M. A. 
Published: June 2005

ABSTRACTTo search for novel transcriptional pathways that are activated in skeletal muscle after endurance exercise, we used cDNA microarrays to measure global mRNA expression after an exhaustive bout of high‐intensity cycling (∼75 min). Healthy, young, sedentary males performed the cycling bout, and skeletal muscle biopsies were taken from the vastus lateralis before, and at 3 and 48 h after exercise. We examined mRNA expression in individual muscle samples from four subjects using cDNA microarrays, used repeated‐measures significance analysis of microarray (SAM) to determine statistically significant expression changes, and confirmed selected results using real‐time RT‐PCR. In total, the expression of 118 genes significantly increased 3 h postcycling and 8 decreased. At 48 h, the expression of 29 genes significantly increased and 5 decreased. Many of these are potentially important novel genes involved in exercise recovery and adaptation, including several involved in 1) metabolism and mitochondrial biogenesis (FOXO1, PPARδ, PPARγ, nuclear receptor binding protein 2, IL‐6 receptor, ribosomal protein L2, aminolevulinate δ‐synthase 2); 2) the oxidant stress response (metalothioneins 1B, 1F, 1G, 1H, 1L, 2A, 3, interferon regulatory factor 1); and 3) electrolyte transport across membranes [Na+‐K+‐ATPase (β3), SERCA3, chloride channel 4]. Others include genes involved in cell stress, proteolysis, apoptosis, growth, differentiation, and transcriptional activation, as well as all three nuclear receptor subfamily 4A family members (Nur77, Nurr1, and Nor1). This study is the first to characterize global mRNA expression during recovery from endurance exercise, and the results provide potential insight into 1) the transcriptional contributions to homeostatic recovery in human skeletal muscle after endurance exercise, and 2) the transcriptional contributions from a single bout of endurance exercise to the adaptive processes that occur after a period of endurance exercise training.
Boundaries and physical characterization of a new domain shared between mammalian 53BP1 and yeast Rad9 checkpoint proteins
Authors: Alpha‐Bazin Béatrice , Lorphelin Alain , Nozerand Nathalie , Charier Gaëlle , Marchetti Charles , Bérenguer Frédéric , Couprie Joël , Gilquin Bernard , Zinn‐Justin Sophie , Quéméneur Eric 
Published: June 2005

AbstractEukaryotic cells have evolved DNA damage checkpoints in response to genome damage. They delay the cell cycle and activate repair mechanisms. The kinases at the heart of these pathways and the accessory proteins, which localize to DNA lesions and regulate kinase activation, are conserved from yeast to mammals. For Saccharomyces cerevisiae Rad9, a key adaptor protein in DNA damage checkpoint pathways, no clear human ortholog has yet been described in mammals. Rad9, however, shares localized homology with both human BRCA1 and 53BP1 since they all contain tandem C‐terminal BRCT (BRCA1 C‐terminal) motifs. 53BP1 is also a key mediator in DNA damage signaling required for cell cycle arrest, which has just been reported to possess a tandem Tudor repeat upstream of the BRCT motifs. Here we show that the major globular domain upstream of yeast Rad9 BRCT domains is structurally extremely similar to the Tudor domains recently resolved for 53BP1 and SMN. By expressing several fragments encompassing the Tudor‐related motif and characterizing them using various physical methods, we isolated the independently folded unit for yeast Rad9. As in 53BP1, the domain corresponds to the SMN Tudor motif plus the contiguous HCA predicted structure region at the C terminus. These domains may help to further elucidate the structural and functional features of these two proteins and improve knowledge of the proteins involved in DNA damage.