bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling Polymer Dielectric/Pentacene Interfaces: On the Role of Electrostatic Energy Disorder on Charge Carrier Mobility
Authors: Martinelli Nicolas G. , Savini Matteo , Muccioli Luca , Olivier Yoann , Castet Frédéric , Zannoni Claudio , Beljonne David , Cornil Jérôme
Published: September 2009

Force‐field and quantum‐chemical calculations are combined to model the packing of pentacene molecules at the atomic level on two polymer dielectric layers (poly(methyl methacrylate) (PMMA) versus polystyrene (PS)) widely used in field‐effect transistors and to assess the impact of electrostatic interactions at the interface on the charge mobility values in the pentacene layers. The results show unambiguously that the electrostatic interactions introduce a significant energetic disorder in the pentacene layer in contact with the polymer chains; a drop in the hole mobility by a factor of 5 is predicted with PS chains while a factor of 60 is obtained for PMMA due to the presence of polar carbonyl groups.
Mesomelic dysplasia with acral synostoses Verloes–David–Pfeiffer type: Follow‐up study documents progressive clinical course
Authors: Isidor Bertrand , Hamel Antoine , Plasschaert Frank , Claus Lieve , Mercier Jacques‐Marie , Mortier Geert R. , Leroy Jules G. , Verloes Alain , David Albert
Published: September 2009

Verloes–David–Pfeiffer mesomelia‐synostoses syndrome is an autosomal‐dominant form of mesomelic dysplasia comprising typical acral synostoses combined with ptosis, hypertelorism, palatal abnormality, CHD, and ureteral anomalies. Since the original reports in 1995, two other patients have been described with this syndrome, one of them the patient reported in 1998 by Day‐Salvatore. In this article, we report on the follow‐up of some of the original cases and review the literature. We confirm that the Verloes–David–Pfeiffer syndrome (VDPS) is a progressive skeletal disorder that despite repeated corrective surgical intervention leads to severe limb deformities. No mutations were detected in the FLNB gene. To date, the cause and the pathogenesis of VDPS remain unknown. The latter is characterized in this study as a syndromic type of skeletal dysplasia because besides congenital malformations and multiple acromelic synostoses arising prenatally, VDPS manifests in postnatal life as a severe osteochondrodysplasia. © 2009 Wiley‐Liss, Inc.
Promoter variants of the cannabinoid receptor 1 gene (CNR1) in interaction with 5‐HTTLPR affect the anxious phenotype
Authors: Lazary Judit , Lazary Aron , Gonda Xenia , Benko Anita , Molnar Eszter , Hunyady Laszlo , Juhasz Gabriella , Bagdy Gyorgy
Published: September 2009

Anxiety is a polygenic condition, and the recently discovered Endocannabinoid System (ECS) is one plausible candidate. Experimental data suggest that the ECS can modulate several neurotransmitter systems, including the serotonergic system, which itself plays a significant role in anxiety. However, to date there is no evidence of gene–gene interactions; indeed genetic studies focusing separately on the two systems provide conflicting data. Thus, the aim of our study was to analyze the interaction of the promoter regions of the serotonin transporter (SLC6A4) and cannabinoid receptor 1 (CNR1) genes on anxiety. We genotyped 706 individuals for the 5‐HTTLPR in the SLC6A4 promoter and 4 SNPs located in the CNR1 promoter region. Anxiety was measured by the State‐Trait Anxiety Inventory (STAI‐S, STAI‐T), the anxiety subscale of TEMPS‐A (TEMPS‐Anx), and the Brief Symptom Inventory (BSI‐Anx). Significant 5‐HTTLPR x CNR1 promoter‐promoter interaction was observed using STAI‐T (P = 0.0006) and TEMPS‐Anx (P = 0.0013). The risk of high anxiety scores on BSI‐Anx was 4.6‐fold greater in homozygous 'GG' rs2180619 in combination with homozygous ‘SS’ 5‐HTTLPR (P = 0.0005) compared to other genotypes. The effect of previously described “TGC” haplotype in the alternative promoter of CNR1 depended both on the conventional promoter polymorphism and the 5‐HTTLPR. Our haplotype and putative transcription binding profile analyses strongly suggest that certain constellations of CB1‐receptor and 5‐HTT promoters yield extremely high or low synaptic 5‐HT concentrations, and these are associated with an anxious phenotype. In conclusion, genetically determined serotonergic and endocannabinoid dysfunctions could lead to a vulnerability causing anxiety disorders and possibly depression. © 2009 Wiley‐Liss, Inc.
Significant association between the C(−1019)G functional polymorphism of the HTR1A gene and impulsivity
Authors: Benko Anita , Lazary Judit , Molnar Eszter , Gonda Xenia , Tothfalusi Laszlo , Pap Dorottya , Mirnics Zsuzsanna , Kurimay Tamas , Chase Diana , Juhasz Gabriella , Anderson Ian M. , Deakin John F.W. , Bagdy Gyorgy
Published: September 2009

Serotonin‐1A (5‐HT1A) receptors are known to play a role in impulsivity‐related behavior. The C(−1019)G functional polymorphism (rs6295) has been suggested to regulate the 5‐HT1A receptor gene (HTR1A) expression in presynaptic raphe neurons, namely, increased receptor concentration and reduced neuronal firing could be associated with the G allele. Previous studies indicate that this polymorphism is associated with aggression, suicide, and several psychiatric disorders, yet its association with impulsivity has rarely been investigated. We studied the relationship between impulsivity and the C(−1019)G polymorphism of the HTR1A in a population sample of 725 volunteers using the Impulsiveness subscale (IVE‐I) of the Eysenck Impulsiveness, Venturesomeness, and Empathy scale and also the Barratt Impulsiveness Scale (BIS‐11). Data were analyzed using analysis of variance with age and gender as covariates and Tukey's HSD post‐hoc test. Post‐hoc analysis revealed that the study had 0.958 power to detect 0.15 effect size. Significant differences between the C(−1019)G genotype groups (GG vs. GC vs. CC) were found. Subjects carrying GG genotype showed significantly higher impulsiveness scores compared to GC or CC carriers for the IVE‐I scale (P = 0.014), for the Motor (P = 0.021), Cognitive Impulsiveness (P = 0.002), and for the BIS total score (P = 0.008) but not for the Nonplanning Impulsiveness (P = 0.520) subscale of the BIS‐11. Our results suggest the involvement of the HTR1A in the continuum phenotype of impulsivity. © 2009 Wiley‐Liss, Inc.
Digestion in the common marmoset (Callithrix jacchus), a gummivore–frugivore
Authors: Power Michael L. , Myers E. Wilson
Published: September 2009

Wild common marmosets (Callithrix jacchus) feed on fruits, insects, and gums, all of which provide different digestive challenges. Much of the ingested mass of fruits consists of seeds. In general, seeds represent indigestible bulk to marmosets and could inhibit feeding if they are not eliminated rapidly. In contrast, gums are β‐linked polysaccharides that require microbial fermentation. Their digestion would benefit from an extended residence time within the gut. Earlier research found that mean retention time (MRT) for a liquid digestive marker (cobalt EDTA) was significantly longer than MRT for a particulate marker (chromium‐mordanted fiber), suggesting that common marmosets preferentially retain liquid digesta. We conducted two four‐day‐long digestion trials on 13 individually housed adult common marmosets fed a single‐item, purified diet in order to examine the relations among MRT of cobalt EDTA and chromium‐mordanted fiber, food dry matter intake (DMI), and apparent digestibility of dry matter (ADDM). We compared the MRT values with the data from the previous study mentioned above and a study using polystyrene beads. There were no significant correlations among MRT, ADDM, or DMI, although increases in DMI between trials were associated with decreases in MRT. ADDM was consistent within individuals between trials; but the mean values ranged from 75.0 to 83.4% among individuals. We found no difference in MRT between the liquid (17.5±1.6 hr) and particulate (17.9±1.4 hr) markers. Although these values were not significantly different than found previously, the MRT for chromium‐mordanted fiber tended to be longer. This probably reflects the relatively small size of the chromium‐mordanted fiber particles used in this study. An inverse relationship between particle size and MRT was evident; the mean MRT of polysterene beads, the largest marker, was only 8.3±1.5 hr. Marmosets appear to retain liquids and small particles within the gut longer than large particles. Am. J. Primatol. 71:957–963, 2009. © 2009 Wiley‐Liss, Inc.
Oil‐absorptive polymeric networks based on dispersed oleophilized nanolayers of laponite within ethylene–propylene–diene monomer vulcanizates
Authors: Essawy H. A. , Essa M. M. , Abdeen Z.
Published: September 2009

Oil‐absorptive polymeric nanocomposites were prepared through the melt blending of soft oleophilic ethylene–propylene–diene monomer and stearyl acrylate as a hydrophobic monomer in the absence and presence of different loadings of untreated and oleophilized laponites with quaternary ammonium salts of n‐alkylamines of different chain lengths (C10, C12, and C16) with dicumyl peroxide as a vulcanizing agent. The samples were then vulcanized at 152°C according to the determined rheometric characteristics to produce nanocomposite vulcanizates of an exfoliated type with limited cavities as revealed by X‐ray diffraction and scanning electron microscopy. The produced vulcanizates were evaluated as oil‐absorptive polymeric networks and proved to be efficient oil sorbents of moderate activity. The oil absorptivity was examined with respect to the stearyl acrylate grafting, the types of oleophilizing agents of clay in comparison with the bare clay, and the clay loading and crosslink density. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Dynamic vulcanization of polyethylene‐based thermoplastic elastomer blends
Authors: Sarkhel Gautam , Choudhury Arup
Published: September 2009

In this investigation, the effects of blending with ethylene–propylene–diene terpolymer and subsequent dynamic curing with sulfur on the macromolecular structure and properties of pure low‐density polyethylene and high‐density polyethylene were studied. The crosslinking efficiency of polyethylene‐based ethylene–propylene–diene terpolymer blends upon dynamic curing was assessed with torque and gel content measurements. The curing of dispersed ethylene–propylene–diene terpolymer in a polyethylene matrix improved both the mechanical and thermomechanical properties as a result of the formation of a crosslink structure in the rubber phase. In view of the electrical applications of this cured blend material, the volume resistivity was measured. The thermal stability of vulcanized polyethylene/ethylene–propylene–diene terpolymer blends was found to be superior to that of unvulcanized blends. In scanning electron microscopy analysis, good interface bonding between the polyethylene matrix and dispersed ethylene–propylene–diene terpolymer was observed for the cured blends. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Hydrogen bonding in blends of polyesters with dipeptide‐containing polyphosphazenes
Authors: Krogman Nicholas R. , Weikel Arlin L. , Nguyen Nhu Q. , Kristhart Katherine A. , Nukavarapu Syam P. , Nair Lakshmi S. , Laurencin Cato T. , Allcock Harry R.
Published: September 2009

New biomedically erodible polymer composites were investigated. Polyphosphazenes containing the dipeptide side groups alanyl–glycine ethyl ester, valinyl–glycine ethyl ester, and phenylalanyl–glycine ethyl ester were blended with poly(lactide‐co‐glycolide) (PLGA) with lactic to glycolic acid ratios of 50 : 50 [PLGA (50 : 50)] and 85 : 15 [PLGA (85 : 15)] with solution‐phase techniques. Each dipeptide ethyl ester side group contains two NH protons that are capable of hydrogen bonding with the carbonyl functions of PLGA. Polyphosphazenes that contain only the dipeptide ethyl ester groups are insoluble in organic solvents and are thus unsuitable for solution‐phase composite formation. To ensure solubility during and after synthesis, cosubstituted polymers with both dipeptide ethyl ester and glycine or alanine ethyl ester side groups were used. Solution casting or electrospinning was used to fabricate polymer blend matrices with different ratios of polyphosphazene to polyester, and their miscibilities were estimated with differential scanning calorimetry and scanning electron microscopy techniques. Polyphosphazenes with alanyl–glycine ethyl ester side groups plus the second cosubstituent were completely miscible with PLGA (50 : 50) and PLGA (85 : 15) when processed via solution‐casting techniques. This suggests that the hydrogen‐bonding protons in alanyl–glycine ethyl ester have access to the oxygen atoms of the carbonyl units in PLGA. However, when the same pair of polymers was electrospun from solution, the polymers proved to be immiscible. Solution‐cast miscible polymer blends were obtained from PLGA (50 : 50) plus the polyphosphazene that was cosubstituted with valinyl–glycine ethyl ester and glycine ethyl ester side groups. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Study on synthesis of polyurethane‐epoxy composite emulsion
Authors: Yi Ying , Ye Fayin , Huang Chou , Guan Jianguo
Published: September 2009

The stable polyurethane‐epoxy composite emulsion with the epoxy‐amine oligomer (DEA‐EP) and the epoxy resin oligomer has been prepared by step‐growth polymerization and controlled crosslinking technique. The emulsion forming transparent films can be cured at room temperature with trimethylolpropane tris (1‐ethyleneimine) propionate (TMPTA‐AZ). The DEA‐EP structure and its reaction with urethane prepolymers were proved by Fourier transform infrared spectra (FTIR). The studies on particle size, the particle size distribution, viscosity, and the films' transmittance (Tr) indicated that both trimethylol propane (TMP) and DEA‐EP contributed to improving the resin blends' compatibility and reducing the viscosity. The epoxy resin content can increase up to 20.0 wt % (based on the total content of the polyurethane and epoxy resin) and the emulsion was still stable. The data from the tensile test experiments showed that with the epoxy content increasing, the tensile strength (σb) and Young's modulus were proportionately raised, but the elongation at break (εb) decreased. Tensile tests also revealed that introducing TMPTA‐AZ as an outside‐crosslinker can increase the tensile strength. By adding 0.3 wt % of TMPTA‐AZ, the εb reduced from 429% to 371% and the σb increased from 4.4 to 13.73 MPa; by adding 1.8 wt % of TMPTA‐AZ, εb of the film was 67% of εb of the film with 0.3 wt % of TMPTA‐AZ, but its σb was 24.77 MPa and 180% of σb of the film with 0.3 wt % of TMPTA‐AZ. The cured films possessed excellent water and toluene resistance: water uptake (48 h, 3.1%; degree of curing: 70%), toluene uptake (210 h, 8%. degree of curing: 70%). Better properties of the composite emulsion will confer it as a potential application in low volatile industrial coatings. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Tracking customer portfolio composition: A factor analysis approach
Authors: Abascal Elena , García Lautre Ignacio , Mallor Fermín
Published: September 2009

In this paper, we address the changing composition of a customer portfolio taking into account actions undertaken by the company to adapt its service offer to market conditions and/or technological innovations. We present a specific methodology to identify clusters of customers in different periods and then compare them over time. The classification process takes into account both qualitative and quantitative aspects of the consumption levels of the services or products offered by the company. The possibility of period‐to‐period variation in the customer portfolio and the service or product offer is also considered, in order to achieve a more realistic scenario.

The core of the proposed methodology is related to the family of exploratory factorial and cluster techniques. The customers are classified by using a bicriterial clustering methodology based on ‘tandem’ analysis (multiple factor analysis+cluster analysis of the main factors). The bicriterial approach allows for a compromise between customers' consumption levels (a quantitative criterion) and their consumption/non‐consumption pattern (a qualitative criterion). The evolution of the customer portfolio composition is explored through multiple correspondence analysis. This technique allows visual comparison of the position of different clusters against time and the identification of key changes in customer consumption behavior. The methodology is tested on realistic customer portfolio scenarios for a major telecommunication company. We simulate various scenarios to show the strengths of our proposal. Copyright © 2009 John Wiley & Sons, Ltd.
A nanosensory device fabricated on a liposome for detection of chemical signals
Authors: Sasaki Yoshihiro , Shioyama Yuka , Tian Wen‐Jie , Kikuchi Jun‐ichi , Hiyama Satoshi , Moritani Yuki , Suda Tatsuya
Published: September 2009

This paper describes construction of a nanosensory device for amplified detection of biologically important amines as chemical signals. The device was inspired by a biological signal transduction system, and was fabricated on an artificial cell membrane through self‐organization of the molecular components, such as a synthetic receptor and a natural enzyme. Selective recognition of biologically important amines was achieved by a synthetic receptor with a pyridoxal moiety, as evaluated by means of electronic absorption spectroscopy. The selectivity in detecting amines as chemical signals mainly depends on hydrophobicity of the amines. The event upon detecting the chemical signals was transmitted to an enzyme by a metal ion acting as a mediator species, and then the enzyme amplified the event by the catalytic reaction to obtain signal output. This paper is realization of a biomimetic signal transduction system using amines as chemical signals and may provide a useful guidepost for designing integrated nanosystems. Biotechnol. Bioeng. 2010;105: 37–43. © 2009 Wiley Periodicals, Inc.
Modeling the influence of cyclodextrins on oral absorption of low‐solubility drugs: I. Model development
Authors: Gamsiz Ece Dilber , Miller Lee , Thombre Avinash G. , Ahmed Imran , Carrier Rebecca Lyn
Published: September 2009

The ability to quantitatively predict the influence of a solubilization technology on oral absorption would be highly beneficial in rational selection of drug delivery technology and formulation design. Cyclodextrins (CDs) are cyclic oligosaccharides which form inclusion complexes with a large variety of compounds including drugs. There are many studies in the literature showing that complexation between CD and drug enhances oral bioavailability and some demonstrating failure of CD in bioavailability enhancement, but relatively little guidance regarding when CD can be used to enhance bioavailability. A model was developed based upon mass transport expressions for drug dissolution and absorption and a pseudo‐equilibrium assumption for the complexation reaction with CD. The model considers neutral compound delivered as a physical mixture with CD in both immediate release (IR) and controlled release (CR) formulations. Simulation results demonstrated that cyclodextrins can enhance, have no effect, or hurt drug absorption when delivered as a physical mixture with drug. The predicted influence depends on interacting parameter values, including solubility, drug absorption constant, binding constant, CD:drug molar ratio, dose, and assumed volume of the intestinal lumen. In general, the predicted positive influence of dosing as a physical mixture with CD was minimal, alluding to the significance of dosing as a preformed complex. The model developed enabled examination of which physical and chemical properties result in oral absorption enhancement for neutral drug administered as a physical mixture with CD, demonstrating the utility of modeling the influence of a drug delivery agent (e.g., CD) on absorption for rational dosage form design. Biotechnol. Bioeng. 2010; 105: 409–420. © 2009 Wiley Periodicals, Inc.
Aggregation of a monoclonal antibody induced by adsorption to stainless steel
Authors: Bee Jared S. , Davis Michele , Freund Erwin , Carpenter John F. , Randolph Theodore W.
Published: September 2009

Stainless steel is a ubiquitous surface in therapeutic protein production equipment and is also present as the needle in pre‐filled syringe biopharmaceutical products. Stainless steel microparticles can cause the aggregation of a monoclonal antibody (mAb). The initial rate of mAb aggregation was second order in steel surface area and zero order in mAb concentration, generally consistent with a bimolecular surface aggregation being the rate‐limiting step. Polysorbate 20 (PS20) suppressed the aggregation yet was unable to desorb the firmly bound first layer of protein that adsorbs to the stainless steel surface. Also, there was no exchange of mAb from the first adsorbed layer to the bulk phase, suggesting that the aggregation process actually occurs on subsequent adsorption layers. No oxidized Met residues were detected in the mass spectrum of a digest of a highly aggregated mAb, although there was a fourfold increase in carbonyl groups due to protein oxidation. Biotechnol. Bioeng. 2010;105: 121–129. © 2009 Wiley Periodicals, Inc.
Biosynthesis of silver nanoparticles using Eclipta leaf
Authors: Jha Anal K. , Prasad Kamlesh , Kumar Vikash , Prasad K.
Published: September 2009

A green, low‐cost and reproducible Eclipta leaves negotiated synthesis of silver nanoparticles is reported. The synthesis is performed at room temperature. X‐ray and transmission electron microscopy analyses are performed to ascertain the formation of Ag nanoparticles. Nanoparticles almost spherical in shape having a size of 2–6 nm are found. UV‐visible study revealed the surface plasmon resonance at 419 nm. The lattice strain is estimated to be 0.0045 using Williamson‐Hall approach. The use of Eclipta for the synthesis of silver nanoparticles offers the benefit of ecofriendliness and amenability for large scale production through scaling up. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
The quaternary structure of tetrameric hemoglobin regulates the oxygen affinity of polymerized hemoglobin
Authors: Palmer Andre F. , Sun Guoyong , Harris David R.
Published: September 2009

This study focuses on the effect of the initial quaternary structure of bovine hemoglobin (Hb) on the physical properties of glutaraldehyde polymerized Hb (PolyHb) solutions. Tense (T) state PolyHb was synthesized by maintaining the pO2 of Hb before and after polymerization at 0 mm Hg. In contrast, relaxed (R) state PolyHb was generated by maintaining the pO2 of Hb before and after polymerization to >749 mm Hg. PolyHb solutions were characterized by measuring the pO2, methemoglobin (metHb) level, molecular weight distribution, O2 affinity and cooperativity coefficient. The metHb level of all PolyHb solutions was low (<2%). Analysis of the molecular weight distribution of PolyHb solutions indicates that in general, the molecular weight of PolyHb solutions increased with increasing cross‐link density. T‐state PolyHb solutions exhibited lower O2 affinity compared to unmodified Hb, whereas R‐state PolyHb solutions exhibited higher O2 affinity compared to unmodified Hb. In addition, the polymerization reaction resulted in a significant decrease in cooperativity that was more pronounced at higher cross‐link densities. All of these results were explained in terms of the quaternary structure of Hb. Taken together, our results yield more insight into the importance Hb's quaternary structure plays in defining the physical properties of glutaraldehyde PolyHb solutions. This information will be useful in designing optimized glutaraldehyde PolyHb oxygen carriers for various applications in transfusion medicine. © 2009 American Institute of Chemical Engineers Biotechnol. Prog. 2009
Local communities responding to ecological challenges—A psycho‐social approach to the Natura 2000 Network
Authors: Mouro Carla , Castro Paula
Published: September 2009

The institutionalization of biodiversity conservation through legal instruments has led to mixed reactions at both the individual and community levels, with conflict and resistance co‐existing with support. The overall purpose of this paper is to describe how rural communities living in areas included in the Natura 2000 Network of protected sites, where local practices of land use are regulated by new legal directives, receive biodiversity conservation goals. Previous studies suggest that this reception is strongly shaped by place identification, but their contradictory results demand further clarification. This study examines the role of psycho‐social variables identified by previous studies as potentially relevant moderators of identification: (a) Vested interest in natural resources, (b) evaluation of the designation process of protected areas and (c) institutional trust. It further extends previous research by analysing the support given to contextually relevant ecological practices. Results reveal a positive link between place identification and attitudes in the high vested interest condition and show that support for conservation practices is better predicted in the high vested interest and low trust conditions. The discussion focuses on the relevance of analysing contextually relevant psycho‐social moderators when attempting to understand how local communities' relation with biodiversity conservation is affected by legislative innovation. Copyright © 2009 John Wiley & Sons, Ltd.
Transition from EcoDam to T4Dam DNA Recognition Mechanism without Loss of Activity and Specificity
Authors: Elsawy Hany , Podobinschi Sveatoslav , Chahar Sanjay , Jeltsch Albert
Published: September 2009

The EcoDam and T4Dam DNA‐(adenine N6)‐methyltransferases both methylate the adenine residue in GATC sites. These enzymes are highly related in amino acid sequence, but they deviate in their contact to the first base pair of the target sequence. EcoDam contacts Gua1 with K9 (which corresponds to T4Dam A6), while T4Dam contacts Gua1 with R130 (which corresponds to EcoDam Y138). We have “transplanted” the T4Dam DNA recognition into EcoDam and show that the EcoDam K9A/Y138R double mutant is highly active and specific. We also studied the intermediates of this transition: The EcoDam K9A variant showed low activity and loss of recognition of Gua1 [Horton, et al., J. Mol. Biol. 2006, 358, 559–570]. In contrast, the EcoDam Y138R variant, which carries both Gua1 recognition elements (K9 from EcoDam and R138 corresponding to R130 from T4Dam), is fully active and specific. This result indicates that a smooth evolutionary pathway exists for changing the EcoDam DNA recognition mode to T4Dam without loss of activity and without generation of evolutionary intermediates with reduced activity. We consistently observed increased activity of EcoDam variants containing Y138R; this suggests that the transition from EcoDam (Gua1 recognition through K9) to T4Dam (Gua1 recognition through R130) was driven by selective pressure towards increased catalytic activity.
A DFT Study of CO Catalytic Oxidation by N2O or O2 on the Co3O4(110) Surface
Authors: Xu Xiang‐Lan , Yang E , Li Jun‐Qian , Li Yi , Chen Wen‐Kai
Published: September 2009

The reaction mechanisms for CO catalytic oxidation by N2O or O2 on the Co3O4(110) surface were studied by DFT slab calculations. CO chemisorbs preferably at a surface Co3+ site. After the Co3+ site is completely covered, CO adsorbs at the neighboring twofold coordinated surface oxygen atom bonded to Co2+ and Co3+ cations, resulting in the formation of CO2 and an oxygen vacancy with a low energy barrier of 0.033 eV, which rationalizes the experimental observation that Co3O4‐based systems are active for CO oxidation at low temperatures. N2O or O2 interacts with the oxygen vacancy site to regenerate the surface, leaving N2 or the activated O2− species to be attacked by the second CO to yield CO2 to proceed with the catalytic cycle. The CO oxidation reaction follows the Mars– van Krevelen mechanism.
Calix[4]arene‐Phosphine Dimers: Precursors of Flexible Metallo‐Capsules and Self‐Compacting Molecules
Authors: Sameni Soheila , Jeunesse Catherine , Matt Dominique , Toupet Loïc
Published: September 2009

The first diphosphines based on a double calixarene, namely 1,4 (or 1,3)‐bis‐(5‐diphenylphosphino‐25,26,27,28‐tetrapropoxycalix[4]aren‐17‐yl)benzene (L2, L3) were each prepared in four steps starting from 5,17‐dibromo‐25,26,27,28‐tetrapropoxycalix[4]arene. Upon reaction of L2 with [Au(tht)(thf)]BF4, (tht=C4H8S) a rigid metallo‐capsule was quantitatively formed, which adopts an oblique form owing to the distinct nature of the spacers linking the two calixarene half‐spheres. In the solid state, the 1,4‐substituted phenylene linker is turned towards the gold ion, suggesting the existence of weak bonding interactions between two aromatic CH protons of this ring and the metal centre (Au⋅⋅⋅H=2.67 Å). In contrast to this gold complex, the related silver complex shows dynamic behaviour in solution, the exchange between two enantiomeric oblique forms being facilitated by the greater stereochemical flexibility of AgI vs. AuI. A heteronuclear 109Ag{1H} HMQC experiment established strong correlations between the CH protons of the phenylene linker and the 109Ag ion. Dynamic behaviour similar to that observed for the silver complex was further observed in trans‐[PtCl2⋅L2], a chelate complex that could be obtained quantitatively from L2 and [PtCl2(PhCN)2]. The intended formation of a chelate complex leading to a capsule with an endo‐oriented metal centre was achieved by reacting L3 with [Pd(allyl)(thf)2]BF4. The complex thus formed constitutes the first organometallic transition metal complex embedded in a cavity with large portals. Binding of [RuCl2(p‐cymene)] to L2 and L3 resulted in self‐compacting bimetallic complexes in which each calixarene basket entraps a Ru(p‐cymene) unit, thereby forming molecules occupying a minimal volume.
Exploiting the capabilities of modern GPUs for dense matrix computations
Authors: Barrachina Sergio , Castillo Maribel , Igual Francisco D. , Mayo Rafael , Quintana‐Ortí Enrique S. , Quintana‐Ortí Gregorio
Published: September 2009

We present several algorithms to compute the solution of a linear system of equations on a graphics processor (GPU), as well as general techniques to improve their performance, such as padding and hybrid GPU‐CPU computation. We compare single and double precision performance of a modern GPU with unified architecture, and show how iterative refinement with mixed precision can be used to regain full accuracy in the solution of linear systems, exploiting the potential of the processor for single precision arithmetic. Experimental results on a GTX280 using CUBLAS 2.0, the implementation of BLAS for NVIDIA® GPUs with unified architecture, illustrate the performance of the different algorithms and techniques proposed. Copyright © 2009 John Wiley & Sons, Ltd.
From Peptides to Non‐Peptide Alpha‐Helix Inducers and Mimetics
Authors: Haridas V.
Published: September 2009

Helix mimetics are good models for investigating the theories of protein folding and also act as good affinity ligands for therapeutic applications due to their biostability and better blood‐brain barrier crossing ability. The helix mimetics display the same spatial and temporal orientation with respect to the amino acid side‐chains of alpha helix part of the protein, which are involved in protein–protein interactions. The designed nonpeptidic molecules with substituents at the appropriate positions on the scaffold can mimic the amino acid side‐chains of a fully folded alpha helix and can competitively bind with the target protein, thus acting as possible therapeutic agents. This was illustrated with examples like p53/MDM2, CD81/CV E2, Bcl‐xL/Bak, gp‐41, and others, with therapeutic relevance. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Lewis‐Acid‐Catalyzed Reactions of Bis(4‐alkoxyphenyl)methanol with (Diarylmethylene)‐ and (Dialkylmethylene)cyclopropanes
Authors: Yao Liang‐Feng , Shi Min
Published: September 2009

Bis(4‐methoxyphenyl)methanol (2a) can be transformed by BF3·OEt2‐catalyzed reactions of (arylmethylene)cyclopropanes 1 to the corresponding polysubstituted cyclopentenes 3 as the major products along with methylenecyclobutanes and dienes as minor products. The reaction conditions are mild, yields are moderate to good. In the reactions of aliphatic methylenecyclopropanes with bis(4‐methoxyphenyl)methanol (2a), cyclopentenes 3o–q were produced in good yields under the standard conditions. Interesting results were obtained from the reactions of 1‐[cyclopropylidene(4‐methoxyphenyl)methyl]‐4‐methoxybenzene (1e) with bis(4‐alkoxyphenyl)methanols 2: polysubstituted cyclopentene derivatives 5 were obtained in good yields under mild reaction conditions. Plausible reaction mechanisms based on the deuterium‐labeling and control experiments are proposed.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Harmonic‐free AC/DC rectifiers for HVDC systems
Authors: Villablanca Miguel E. , Rojas Felix E.
Published: September 2009

This paper presents an innovative method for reducing current distortion on the AC side of 12‐pulse series‐connected line‐commutated AC/DC rectifiers. Furthermore, the overlap conduction of thyristors is completely eliminated. The methodology involves an accurate shaping of the DC current by using two self‐commutated switches. This DC‐current shaping is reflected back into the shaping of the AC input currents, which become pure sine waves. Rectifying operation is possible with a simple control circuit, which is able to deal with both rapid load variations and failures in the self‐commutated switches. HVDC application of this innovative method is briefly examined, together with experimental results showing both the steady state and transient behavior of the technology by using a 380‐V 20‐kVA 50‐Hz laboratory prototype. Copyright © 2009 John Wiley & Sons, Ltd.
The novel adaptive sliding mode controller for synchronous reluctance motor speed drive
Authors: Chen Chien‐An , Chiang Huann‐Keng , Lin Bor‐Ren
Published: September 2009

This paper presents an adaptive sliding mode speed control design procedure for robust stabilization and disturbance rejection of the synchronous reluctance motor (SynRM) drive system. In general, the conventional sliding mode control design method is assumed that the upper boundary of parameter variations and external disturbances is known and the sign function is used. Therefore, it causes high frequency chattering and high gain phenomenon. In this paper, we proposed an adaptive sliding mode control of the SynRM speed drive system to avoid the above drawbacks. This method utilizes Lyapunov function candidate to guarantee the convergence and track the speed command of the SynRM drive system asymptotically. The estimator of parameter variations and external disturbances is designed to estimate the unknown uncertainty values in real‐time. This is different from conventional adaptive sliding mode control to estimate the unknown uncertainty upper boundary. Finally, we employ the experiments to validate the proposed method. Copyright © 2009 John Wiley & Sons, Ltd.
A Hermite finite element method for incompressible fluid flow
Authors: Holdeman J. T.
Published: September 2009

We describe some Hermite stream function and velocity finite elements and a divergence‐free finite element method for the computation of incompressible flow. Divergence‐free velocity bases defined on (but not limited to) rectangles are presented, which produce pointwise divergence‐free flow fields (∇·uh≡0). The discrete velocity satisfies a flow equation that does not involve pressure. The pressure can be recovered as a function of the velocity if needed. The method is formulated in primitive variables and applied to the stationary lid‐driven cavity and backward‐facing step test problems. Copyright © 2009 John Wiley & Sons, Ltd.
Multiple‐relaxation‐time lattice Boltzmann computation of channel flow past a square cylinder with an upstream control bi‐partition
Authors: Moussaoui M. A. , Jami M. , Mezrhab A. , Naji H. , Bouzidi M.
Published: September 2009

The present paper deals with the application of the multiple‐relaxation‐time lattice Boltzmann equation (MRT‐LBE) for the simulation of a channel flow with a bi‐partition located upstream of a square cylinder in order to control the flow. Numerical investigations have been carried out for different heights and positions of the bi‐partition at Reynolds number of 250. Key computational issues involved are the computation of fluid forces acting on the square cylinder, the vortex shedding frequency and the impact of such bluff body on the flow pattern. A particular attention is paid to drag and lift coefficients on the square cylinder. The predicted results from MRT‐LBE simulations show that in most cases, the interaction was beneficial insofar as the drag of the square block was lower with the bi‐partition than without it. Fluctuating side forces due to vortex shedding from the main body were also reduced for most bi‐partition positions. Copyright © 2009 John Wiley & Sons, Ltd.
Willingness‐to‐pay to avoid the time spent and discomfort associated with screening colonoscopy
Authors: Jonas Daniel E. , Russell Louise B. , Chou Jon , Pignone Michael
Published: September 2009

Background: The screening colonoscopy process requires a considerable amount of time and some discomfort for patients.

Objective: We sought to use willingness‐to‐pay (WTP) to value the time required and the discomfort associated with screening colonoscopy. In addition, we aimed to explore some of the differences between and potential uses of the WTP and the human capital methods.

Methods: Subjects completed a diary recording time and a questionnaire including WTP questions to value the time and discomfort associated with colonoscopy. We also valued the elapsed time reported in the diaries (but not the discomfort) using the human capital method.

Results: 110 subjects completed the study. Mean WTP to avoid the time and discomfort was $263. Human capital values for elapsed time were greater. Linear regressions showed that WTP was influenced most by the difficulty of the preparation, which added $147 to WTP (p=0.03).

Conclusions: WTP values to avoid the time and discomfort associated with the screening colonoscopy process were substantially lower than most of the human capital values for elapsed time alone. The human capital method may overestimate the value of time in situations that involve an irregular, episodic series of time intervals, such as preparation for or recovery after colonoscopy. Copyright © 2009 John Wiley & Sons, Ltd.
Workplace and organizational accident causation factors in the manufacturing industry
Authors: Katsakiori Panagiota , Kavvathas Aristomenis , Athanassiou George , Goutsos Stavros , Manatakis Emmanuel
Published: September 2009

Labor inspectors investigate accidents to identify possible accident causes, initiate prosecution, and plan future accident prevention. The Method of Investigation for Labor Inspectors (MILI) was designed to help them to identify workplace and organizational factors in addition to immediate factors and legal breaches. The present study analyzes the impact of workplace (work design and provision of unsafe equipment) and organizational factors (training and employee involvement) on accident causation and validates MILI on real accident cases. Accident data from the manufacturing sector are analyzed with LISREL structural equation modeling. Results confirm the relationship between work design and training as well as between provision of unsafe equipment and employee involvement. The present study provides evidence that MILI is a structured accident investigation method allowing multiple accident causation factors to be revealed and that it could help all interested parts (not only labor inspectors, but companies as well) to thoroughly investigate occupational accidents. © 2009 Wiley Periodicals, Inc.
Identifying the age profile of patent citations: new estimates of knowledge diffusion
Authors: Mehta Aditi , Rysman Marc , Simcoe Tim
Published: September 2009

Previous research studies the age profile of patent citations to learn about knowledge flows over time. However, identification is problematic because of the collinearity between application year, citation year, and patent age. We show empirically that a patent's ‘citation clock’ does not start until it issues, and propose a highly flexible identification strategy that uses the lag between application and grant as a source of exogenous variation. We examine the potential bias if our assumptions are incorrect, and discuss extensions into other research areas. Finally, we use our method to re‐examine prior results on citation age profiles of patents from different technological fields and application year cohorts. Copyright © 2009 John Wiley & Sons, Ltd.
Why are gasoline prices sticky? A test of alternative models of price adjustment
Authors: Douglas Christopher , Herrera Ana María
Published: September 2009

Macroeconomic models of business cycles rely on the assumption that firms adjust prices infrequently to generate the short‐run non‐neutrality of money documented by the monetary transmission literature. They posit different mechanisms to generate price stickiness, with correspondingly different implications for inflation dynamics. Using an autoregressive conditional binomial model, we test which mechanism is most consistent with the pattern of price adjustment found in daily wholesale gasoline price data. Our results lead us to reject menu costs and information‐processing delays but suggest that strategic considerations related to the idea of ‘fair pricing’ play an important role in accounting for price stickiness. Copyright © 2009 John Wiley & Sons, Ltd.
Nuclear matrix protein, prohibitin, was down‐regulated and translocated from nucleus to cytoplasm during the differentiation of osteosarcoma MG‐63 cells induced by ginsenoside Rg1, cinnamic acid, and tanshinone IIA (RCT)
Authors: Shi Song‐Lin , Li Qi‐Fu , Liu Qing‐Rong , Xu Dong‐Hui , Tang Jian , Liang Ying , Zhao Zhen‐Li , Yang Li‐Ming
Published: September 2009

Ginsenoside Rg1, cinnamic acid, and tanshinone IIA (RCT) are effective anticancer and antioxidant constituents of traditional Chinese herbal medicines of Ginseng, Xuanseng, and Danseng. The molecular mechanisms of anticancer effects of those constituents and their targets are unknown. Prohibitin, an inner membrane‐bound chaperone in mitochondrion involved in the regulation of cell growth, proliferation, differentiation, aging, and apoptosis, was chosen as a candidate molecular target because of its frequent up‐regulation in various cancer cells. We demonstrated that prohibitin existed in the filaments of the nuclear matrix of the MG‐63 cell and its expression was down‐regulated by the treatment of RCT using proteomic methodologies and Western blot analysis. Immunogold electro‐microscopy also found that prohibitin was localized on nuclear matrix intermediate filaments (NM‐IF) that had undergone restorational changes after RCT treatment. Prohibitin may function as a molecular chaperone that might interact with multiple oncogenes and tumor suppressor genes. We found that oncogenes c‐myc and c‐fos and tumor suppressor genes P53 and Rb were regulated by RCT as well and that these gene products co‐localized with prohibitin. Our study identified prohibitin as a molecular target of the effective anticancer constituents of Ginseng, Xuanseng, and Danseng that down‐regulated prohibitin in nuclear matrix, changed prohibtin trafficking from nucleolus to cytoplasm, and regulated several oncogenes and tumor suppressor genes. Prohibitin downregulation and cellular trafficking from nucleolus to cytoplasm indicated RCT protective roles in cancer prevention and treatment. J. Cell. Biochem. 108: 926–934, 2009. © 2009 Wiley‐Liss, Inc.
Oxidized low density lipoprotein decreases Rankl‐induced differentiation of osteoclasts by inhibition of Rankl signaling
Authors: Mazière Cécile , Louvet Loïc , Gomila Cathy , Kamel Said , Massy Ziad , Mazière Jean‐Claude
Published: September 2009

The role of OxLDL in the generation and progression of atherosclerosis is well admitted. In addition, it is well known that atherosclerosis is often accompanied by perturbations in bone remodeling, resulting in osteoporosis. In the current studies, the effect of Cu2+‐oxidized LDL (OxLDL) on RANKL‐induced RAW264.7 mouse monocytes‐macrophages differentiation to osteoclasts and on RANKL signaling pathway was investigated. OxLDL, within the range of 10–50 µg protein/ml, prevented RANKL‐induced generation of multinucleated osteoclast‐like cells and RANKL‐induced tartrate resistant acid phosphatase (TRAP) activity. OxLDL also prevented the RANKL‐induced phosphorylation of ERK, p38 and JNK kinases, together with the RANKL‐induced DNA binding activities of NFkappaB and NFAT transcription factors. Concomitantly, OxLDL enhanced RANKL‐induced generation of reactive oxygen species in a dose‐dependent manner. The antioxidant glutathione (GSH) prevented whereas the prooxidant compound buthionine‐sulfoximine (BSO) enhanced the effect of OxLDL on RANKL‐induced oxidative stress and RANKL‐induced differentiation. Finally, OxLDL also prevented RANKL‐induced TRAP activity and RANKL‐induced bone resorbing activity of human peripheral blood mononuclear cells. These results demonstrate that OxLDL, by generation of an intracellular oxidative stress, prevents the differentiation of osteoclasts by inhibition of RANKL signaling pathway. This might be related to the fact that atherosclerosis is accompanied by perturbations in bone and vascular remodeling, leading to osteoporosis and vascular calcification. J. Cell. Physiol. 221: 572–578, 2009. © 2009 Wiley‐Liss, Inc.
Rab22B is expressed in the CNS astroglia lineage and plays a role in epidermal growth factor receptor trafficking in A431 cells
Authors: Ng Ee Ling , Ng Jun Jie , Liang Fengyi , Tang Bor Luen
Published: September 2009

The expression profile and functions of the brain‐enriched Rab22B/Rab31 small GTPase had remained uncharacterized. Using specific antibodies against Rab22B, we found the protein to be exceptionally enriched in nestin and RC2‐positive radial glia of the embryonic mouse brain. In the adult brain, Rab22B is rather specifically expressed in glial fibrillary acidic protein (GFAP)‐positive mature astrocytes, but is not clearly detectable in either 2′,3′‐cyclic nucleotide 3′‐phosphodiesterase (CNPase)‐positive mature oligodendrocytes or βIII‐tubulin (TuJ)‐positive neurons. In probing for specific functions of Rab22B, we found that Rab22B silencing in A431 cells resulted in abnormal trafficking of the epidermal growth factor receptor (EGFR), Texas‐red‐labeled EGF, and the cation‐independent mannose 6‐phosphate receptor (M6PR). Affinity pull‐down assays and co‐immunoprecipitation analysis indicated that Rab22B could associate with EGFR in a GTP‐dependent manner. Rab22B is thus a Rab protein specifically expressed in the astroglia lineage and may have a role in regulating EGFR trafficking in some cell types. Given that EGFR signaling modulates astrocyte development and oncogenesis of multiple cell types, Rab22B may thus have specific developmental or pathophysiological roles in cell types which it is enriched in. J. Cell. Physiol. 221: 716–728, 2009. © 2009 Wiley‐Liss, Inc.