bluuebunny/crossref_metadata_2025_split huggingface dataset:
Confounder summary scores when comparing the effects of multiple drug exposures
Authors: Cadarette Suzanne M. , Gagne Joshua J. , Solomon Daniel H. , Katz Jeffrey N. , Stürmer Til 
Published: September 2009

AbstractPurposeLittle information is available comparing methods to adjust for confounding when considering multiple drug exposures. We compared three analytic strategies to control for confounding based on measured variables: conventional multivariable, exposure propensity score (EPS), and disease risk score (DRS).MethodsEach method was applied to a dataset (2000–2006) recently used to examine the comparative effectiveness of four drugs. The relative effectiveness of risedronate, nasal calcitonin, and raloxifene in preventing non‐vertebral fracture, were each compared to alendronate. EPSs were derived both by using multinomial logistic regression (single model EPS) and by three separate logistic regression models (separate model EPS). DRSs were derived and event rates compared using Cox proportional hazard models. DRSs derived among the entire cohort (full cohort DRS) was compared to DRSs derived only among the referent alendronate (unexposed cohort DRS).ResultsLess than 8% deviation from the base estimate (conventional multivariable) was observed applying single model EPS, separate model EPS or full cohort DRS. Applying the unexposed cohort DRS when background risk for fracture differed between comparison drug exposure cohorts resulted in −7 to + 13% deviation from our base estimate.ConclusionsWith sufficient numbers of exposed and outcomes, either conventional multivariable, EPS or full cohort DRS may be used to adjust for confounding to compare the effects of multiple drug exposures. However, our data also suggest that unexposed cohort DRS may be problematic when background risks differ between referent and exposed groups. Further empirical and simulation studies will help to clarify the generalizability of our findings. Copyright © 2009 John Wiley & Sons, Ltd.
Surface infusion of gold nanoparticles into processed thermoplastics
Authors: Lentz Daniel M. , Pyles Robert A. , Hedden Ronald C. 
Published: September 2009

AbstractStable dispersions of gold (Au0) nanoparticles are produced in a few commercially important thermoplastics using a novel surface infusion technique. The thermoplastic article is immersed in a dilute solution of HAuCl4 in a ternary solvent mixture held well below the melt‐processing temperature of the plastic. Rapid infusion of plasticizing solvents and HAuCl4 is achieved for several thermoplastic polyurethane elastomers and an acrylic‐pyrrolidinone copolymer. A second infusion of triethylamine, a reducing agent, produces Au0 nanoparticles in a surface layer of (10–30 μm) depth. Precipitation of Au0 nanoparticles is arrested by the high viscosity of the plasticized polymer matrix, resulting in a stable dispersion, but formation of aggregates is possible in some plastics. The Au0 particle size distribution can be manipulated by changing processing conditions that affect the formation of aggregates, such as the concentrations of HAuCl4 and plasticizers. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
A facile synthesis method of nickel nanotubes assisted by polyethylene glycol
Authors: Tao Feifei , Gao Cuiling , Xu Zheng , Xue Ziling 
Published: September 2009

AbstractUsing an easy and general way, magnetic metal nickel nanotubes are successfully fabricated by adding polyethylene glycol (PEG200, PEG2000, and PEG20000) in the common electrolyte solution combined with electrodeposition technique. This method is very easy, effective, and facile. Especially, the pore wall of the template need not be modified, and their wall thickness can be effectively controlled by adjusting the experimental parameters, such as the electric current density, the concentration of polyethylene glycol, and the electrodeposition time. The possible formation mechanism is proposed. The magnetic measurement of Ni nanotubes indicates that the difference of the polymers used in the preparation does not have a notable effect on their magnetic properties. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Effects of organic encapsulation on the properties of magnetic PLLA/Fe3O4 composites
Authors: Zhang Jing , Yu Demei , Lv Anlin , Xie Yunchuan , Hu Guohe , Liang Honglu , Min Chao 
Published: September 2009

AbstractOrganic‐encapsulated Fe3O4 magnetic microspheres (MMS) were synthesized and used to prepare PLLA (poly (L‐lactic acid))/MMS composites. The effects of organic encapsulation on the mechanical, thermal, and magnetic properties of the composites were investigated. When compared with the PLLA/Fe3O4 composite, the elongation ratio of the PLLA/MMS composite improved significantly (by nearly 300%). Scanning electron microscope (SEM) images of the fracture morphology revealed an interesting “silking” phenomenon within the PLLA/MMS composite, which explains the greatly improved toughness. The decreased crystallinity and increased thermal stability of the PLLA/MMS composite suggest the existence of strong interacting forces between the PLLA molecules and the organic layer of the MMS particles, thereby limiting the mobility of the macromolecular chains. A study of the composites' magnetic properties indicated that the saturation magnetization was determined by the relative Fe3O4 content in the matrix, but not the types of the filling particles. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Study of the molecular orientation heterogeneity in polypropylene injection‐molded parts by Raman spectroscopy
Authors: Martin J. , Margueron S. , Fontana M. , Cochez M. , Bourson P. 
Published: September 2009

AbstractPolarized Raman microspectroscopy has been used to study oriented‐skin layers induced in injection‐molded isotactic polypropylene (iPP) parts. A method based on the intensity sensitivity of several Raman bands to laser light polarization was employed to estimate the degree of molecular orientation in iPP. The skin‐core molecular orientation heterogeneity in injection‐molded iPP is then evaluated via two different experimental methods. Results show that an in‐depth profile using micro‐Raman confocal technique is as valuable as an edge profile performed on a sample cross‐section because both are correlated with optical microscopy measurements. Both Raman measurements are in good agreement with optical microscopy measurements. The skin development was found to be narrowly related to the shear strain rate at the mold walls. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Preparation of extruded melt‐mixed polypropylene/montmorillonite nanocomposites with inline monitoring
Authors: Bertolino Marcelo K. , Canevarolo Sebastião V. 
Published: September 2009

AbstractThis article advances the use of an inline optical detector to monitor the disaggregation of the montmorillonite (MMT) clay tactoids during the preparation of polypropylene (PP)/MMT nanocomposites via polymer melt compounding. During the exfoliation of the tactoids their size are reduced below the minimum particle size to produce light extinction and so, the signal of the inline detector reduces as the nanosize composite is formed. The measurement is done at the transient state with the MMT clay added as a pulse with constant weight into the PP extrusion melt flow and followed by the optical detector. The data comes out as the common residence time distribution curves having its maximum intensity related to the tactoids average particle size, keeping all other variables constants. The light extinction was measured for composites with different clays (Cloisite® 15A, 30B, Na+, and Sintered 20A) using the same PP grafted with maleic anhydride compatibilizer. The dissaglomeration/exfoliation efficiency increases as: ‘‘Sintered 20A’’ < ‘‘Na+ clay’’ < ‘‘organo‐modified clay’’ < ‘‘organo‐modified clay + compatibilizer’’. The best result is obtained using Cloisite® 15A and Cloisite® 20A following the expected reduction of the particle size obtained during a nanocomposite melt processing. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Nanocomposites of silver nanoparticle and dinonylnaphthalene disulfonic acid‐doped thermoreversible polyaniline gel
Authors: Garai Ashesh , Chatterjee Shreyam , Nandi Arun K. 
Published: September 2009

AbstractSilver/polyaniline‐dinonylnaphthalene disulfonic acid (PANI‐DNNDSA) gel nanocomposites are prepared from the reduction of silver salt by polyaniline in formic acid medium. Scanning electron micrographs (SEM) indicate the presence of three‐dimensional fibrillar network structure and the silver nanoparticles remain dispersed within the PANI‐DNNDSA fibrillar network. Differential scanning calorimetric (DSC) study shows reversible first‐order phase transition characterizing the composite to behave as a thermoreversible gel. Transmission electron micrographs (TEM) show a decrease of nanoparticle size with increasing AgNO3 concentration. Wide angle X‐ray scattering (WAXS) patterns show lamellar structure in the gel as well as in the gel metal nanocomposites (GMNCs) and the two melting peaks in the DSC patterns correspond to the melting of monolayer and bilayer crystals produced from the interdigitation of DNNDSA tails anchored from PANI chains within the PANI lamella. The above melting points are greater in the GMNCs than that of pure gel indicating the formation of complex melting thermogram with crystallites produced from the anchored surfactants tails at the surface of Ag nanoparticles. The GMNCs show a higher thermal stability than that of pure PANI‐DNNDSA gel. PANI‐DNNDSA gel has an emission peak at 354 nm but fluorescence quenching occurs in the GMNCs and the emission peak becomes red shifted. Also in the UV–vis spectra the π band‐polaron band transition peak shows a red shift and the DC conductivity increases with increasing Ag nanoparticle concentration in the GMNCs. The current (I)–voltage (V) characteristic curves indicate Ohmic nature of conductivity of the gel and the current at the same voltage increases appreciably with increasing Ag nanoparticle concentration. These GMNCs are easily processible due to its thermoreversible nature. So, an easily processible, thermally stable and highly conducting DNNDSA‐doped PANI‐Ag gel nanocomposite with interesting photoluminescent property has been successfully developed suitable for optoelectronic applications. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
A proteomic and transcriptomic view of amino acids catabolism in the yeast Yarrowia lipolytica
Authors: Mansour Soulaf , Bailly Julie , Delettre Jérôme , Bonnarme Pascal 
Published: September 2009

AbstractThe yeast Yarrowia lipolytica has to develop dynamic metabolic adaptation mechanisms to survive within the cheese habitat. The availability of amino acids (AAs) is of major importance for microbial development and/or aroma production during cheese ripening. Using 2‐D protein gel electrophoresis, we analyzed the adaptation mechanisms of Y. lipolytica for AAs limitation or supplementation in a batch culture containing lactate as a carbon source. Proteome analyses allow the identification of 34 differentially expressed proteins between the culture conditions. These analyses demonstrated that prior to the AAs addition, mainly proteins involved in the oxidative stress of the yeast were induced. Following the AAs addition, yeast cells reorganize their metabolism toward AAs catabolism and also generate a higher induction of proteins related to carbon metabolism and proteins biosynthesis. Using real‐time reverse transcription PCR, we re‐evaluated the expression of genes encoding proteins involved in these processes. The expression levels of the genes were in accordance with the proteomic results, with the up‐regulation of genes encoding a branched‐chain amino transferase BAT2, a pyruvate decarboxylase PDC6 and an Hsp70 protein SSZ1 involved in protein biosynthesis. A volatile compound analysis was also performed, and increased production of dimethyldisulfide from methionine and 3‐methyl‐butanal from leucine was observed in media supplemented with AAs.
Al Top Cathode Deposition on OLED Using DC Magnetron Sputtering
Authors: Gil Tae Hyun , May Christian , Lakner Hubert , Leo Karl , Keller Stefan 
Published: September 2009

AbstractWe fabricated OLEDs having the evaporated Yb cathode and the sputtered Al cathode. Magnetron sputtering is a versatile deposition method, but the energetic particles during sputtering process can damage the underlying organic layers. We applied various process parameters to explain the role of Ar neutrals quoting the former researches. OLEDs showed almost comparable degradation under the discharge voltage of 300 V, but serious degradations were found at the discharge voltage of over 300 V and the low process pressure. The degradations influenced on the lifetime of OLED, and the measured luminance decay was much larger than the OLED having the evaporated Yb cathode due to the high leakage currents.
Molecular mechanism of allosteric communication in the human PPARα‐RXRα heterodimer
Authors: Venäläinen Tuomas , Molnár Ferdinand , Oostenbrink Chris , Carlberg Carsten , Peräkylä Mikael 
Published: September 2009

AbstractThe peroxisome proliferator‐activated receptor α (PPARα) is a nuclear receptor (NR) that forms a heterodimeric transcription factor complex with the retinoid X receptor α (RXRα). The phenomenon that the heterodimer can be activated by both PPARα and RXRα ligands, while both ligands have a synergistic effect on its activity suggests that there is an allosteric communication within the heterodimer. In this study, the molecular mechanism of this allosteric signaling was studied by molecular dynamics (MD) simulations and some of the residues involved in this communication were tested experimentally. Multiple MD simulations were done for the PPARα‐RXRα heterodimer ligand‐binding domains (LBDs) without ligands, with agonistic ligand bound to RXRα or PPARα, and ligand bound to both receptors. Fluctuation calculations and structural clustering analysis of the heterodimer MD simulations showed that ligand binding to RXRα decreases fluctuations of large parts of PPARα, most notably helices 3 and 4 at the coactivator binding site, which presumably stabilizes the coactivator binding to heterodimer complex. The dynamics of helix 8–9 loop and helix 10/11 located at the heterodimeric interface were affected by RXRα ligand binding, suggesting that these parts of the dimer are involved in allosteric communication. Experimental data complemented this view by showing that a large set of residues at the heterodimerization surface has a role in the communication. These results provided evidence that RXRα ligand binding‐induced stabilization of PPARα coactivator binding site has a role in the permissive and synergistic activation of the PPARα‐RXRα heterodimer. Proteins 2010. © 2009 Wiley‐Liss, Inc.
Effect of synthesis process on the Young's modulus of titanate nanowire
Authors: Chang Ming , Deka Juti Rani , Chang Feng Cheng 
Published: September 2009

AbstractNanocrystalline materials have attracted a great deal of attention because of their intriguing size‐/shape‐dependent properties. Titanate nanowires have been synthesized from titania (TiO2) nanoparticles using conventional hydrothermal process. Young's moduli of as‐prepared titanate nanowires have been determined in situ from the buckling instability of the nanowires due to application of axial compressive load using a nanomanipulator inside a scanning electron microscope. Based on Euler's buckling model, the Young's moduli of the nanowires are determined to be 32 ± 11 GPa. The obtained Young's moduli have been compared to that of the titanate nanowires prepared with microwave hydrothermal process to study the effect of synthesis process on the mechanical behavior of nanomaterials. The prolonged holding time of a conventional hydrothermal process helps in the significant enhancement of the Young's modulus of nanowire in comparison to that prepared with microwave hydrothermal process.
Effective surface passivation of crystalline silicon using ultrathin Al2O3 films and Al2O3/SiNx stacks
Authors: Schmidt Jan , Veith Boris , Brendel Rolf 
Published: September 2009

AbstractWe measure surface recombination velocities (SRVs) below 10 cm/s on p‐type crystalline silicon wafers passivated by atomic–layer–deposited (ALD) aluminium oxide (Al2O3) films of thickness ≥10 nm. For films thinner than 10 nm the SRV increases with decreasing Al2O3 thickness. For ultrathin Al2O3 layers of 3.6 nm we still attain a SRV < 22 cm/s on 1.5 Ω cm p‐Si and an exceptionally low SRV of 1.8 cm/s on high‐resistivity (200 Ω cm) p‐Si. Ultrathin Al2O3 films are particularly relevant for the implementation into solar cells, as the deposition rate of the ALD process is extremely low compared to the frequently used plasma‐enhanced chemical vapour deposition of silicon nitride (SiNx). Our experiments on silicon wafers passivated with stacks composed of ultrathin Al2O3 and SiNx show that a substantially improved thermal stability during high‐temperature firing at 830 °C is obtained for the Al2O3/SiNx stacks compared to the single‐layer Al2O3 passivation. Al2O3/SiNx stacks are hence ideally suited for the implementation into industrial‐type silicon solar cells where the metal contacts are made by screen‐printing and high‐temperature firing of metal pastes. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Selective imaging of positively charged polar and nonpolar lipids by optimizing matrix solution composition
Authors: Sugiura Yuki , Setou Mitsutoshi 
Published: September 2009

AbstractPrevious studies have shown that matrix‐assisted laser desorption/ionization–imaging mass spectrometry (MALDI‐IMS) is useful for studying the distribution of various small metabolites, particularly lipids. However, in this technique, selective ionization of the target molecules is imperative, particularly when analyzing small molecules. Since the sample clean‐up procedures available for the MALDI‐IMS of small metabolites are limited, the tissue sample will contain numerous molecular species other than the target molecules. These molecules will compete for ionization resulting in severe ion suppression. Hence, it is necessary to develop and optimize a sample preparation protocol for the target molecules. In this study, through model experiments using reference compounds, we optimized the composition of the matrix solution used for positively charged lipids in terms of the concentration of the organic solvent and presence/absence of alkali metal salts. We demonstrated that a high concentration of organic solvent in the matrix solution favors the preferential detection of lipids over peptides. The presence of alkali metal salts in the matrix solution was favorable for the detection of polar lipids, while a salt‐free matrix solution was suitable for the detection of nonpolar lipids. Furthermore, potassium salts added to the matrix solution caused merging of various lipid adducts (adducts with proton, sodium, and potassium) into one single potassiated species. Using the optimized protocols, we selectively analyzed phosphatidylcholine (PC) and triacylglycerol (TG) with different fatty acid compositions in a rat kidney section. Copyright © 2009 John Wiley & Sons, Ltd.
Characterization of S‐thiolation on secreted proteins fromE. coliby mass spectrometry
Authors: Liu Peiran , Tarnowski Malloree A. , O'Mara Brian W. , Wu Wei , Zhang Haiying , Tamura James K. , Ackerman Michael S. , Tao Li , Grace Michael J. , Russell Reb J. 
Published: September 2009

AbstractS‐thiolation is a reversible post‐translational modification in which thiol metabolites of low molecular masses are linked to protein sulfhydryl groups through disulfide bonds. This modification is commonly observed in recombinant proteins secreted fromE. colicells. Since it can alter protein functions and introduce molecular heterogeneity, S‐thiolation is undesirable for recombinant protein production. To date, few published studies have characterized thiol modifiers or investigated the mechanism of S‐thiolation in recombinant proteins. In this work, reversed‐phase liquid chromatography and mass spectrometry were used to characterize four of the most abundant thiol modifiers on recombinant proteins secreted fromE. coliBL21 (DE3) strain. These thiol modifiers have been identified as glutathione, 4‐phosphopantetheine, gluconoylated glutathione, and dephosphorylated coenzyme A. S‐thiolation by these thiol modifiers increases protein mass by 305, 356, 483, and 685 Da, respectively. These specific mass increases can be used as markers for identifying S‐thiolation in recombinant proteins. Copyright © 2009 John Wiley & Sons, Ltd.
Derivatization aids in the determination of end groups in poly(alkylene glycol)s by matrix‐assisted laser desorption/ionization mass spectrometry
Authors: Borisov Roman S. , Polovkov Nikolai Yu. , Zaikin Vladimir G. 
Published: September 2009

AbstractA method for end‐group characterization by matrix‐assisted laser desorption/ionization (MALDI) mass spectrometry following preliminary derivatization with N,O‐bis(trimethylsilyl)trifluoroacetamide (BSTFA) and capryloyl chloride is described and applied to poly(alkylene glycol)s. The MALDI mass spectra of the products revealed peaks of sodiated derivative cations, whose shift by the respective increments allowed the determination of the number of end functional groups with active hydrogens. This approach is particularly efficient for the distinction of cyclic and linear dehydration products among minor components. Copyright © 2009 John Wiley & Sons, Ltd.
Formation of Resistant Starch in Corn Starch and Estimation of its Content from Physicochemical Properties
Authors: Kim Sung‐Kon , Kwak Jae‐Eun 
Published: September 2009

AbstractThe effect of autoclaving temperatures (100‐120°C) on yields of enzyme‐resistant starch (RS) from normal corn starch and the physicochemical properties of autoclaved‐cooled starches were studied. The RS content increased linearly with increasing autoclaving temperature (R2 = 0.993) and the number of autoclaving‐cooling cycles at an autoclaving temperature of 120°C. The effect of the number of autoclaving‐cooling cycles was more pronounced than that of temperature. The swollen starch weight measured at 60°C slightly increased as the RS content increased, and then drastically decreased with the continous increase of the RS content (R2 = ‐0.969). As the RS content increased, all parameters of Rapid Visco Analyser (RVA) viscosity except breakdown decreased. Log RVA peak viscosity showed a negative correlation with the RS content (R2 = ‐0.986). The enthalpy in the differential scanning calorimetry (DSC) endotherm corresponding to the transitions of RS linearly increased as the RS content increased (R2 = 0.988). The RS content of the heat‐treated starch estimated from the relationship between RS content and swollen starch weight at 60°C, log RVA peak viscosity or DSC enthalpy was in good agreement with that determined with the standard method.
Effect of Fatty Acid Addition on the Properties of Biopolymer Films Based on Lipophilic Maize Starch and Gelatin
Authors: Fakhouri Farayde M. , Fontes Luciana C. B. , Innocentini‐Mei Lucia H. , Collares‐Queiroz Fernanda P. 
Published: September 2009

AbstractIn the presented work, composed layer films based on lipophilic starch and gelatin were produced containing different amounts of fatty acids (palmitic, lauric, myristic, capric, caproic and caprylic); i.e., 5, 15, 25 and 50%, using sorbitol as the plasticizer. All films were prepared by casting in an acrylic plate and their barrier properties (vapor permeability), as well as their mechanical (tensile strength and elongation), physicochemical (water solubility) and physical (opacity and thickness) properties were measured. The addition of fatty acids to the biopolymer films increased their thickness, opacity and elongation. On the other hand, the addition of fatty acids decreased the tensile strength and water vapor permeability of the biopolymer films for all formulations studied. The fatty acid concentration found to be effective in reducing the biopolymer film permeability varied between 15 and 25%.