bluuebunny/crossref_metadata_2025 huggingface dataset:
Elimination of oscillations in fermentation processes
Authors: Sridhar Lakshmi N.
Published: October 2010

Fermentation processes that are used to produce ethanol exhibit oscillatory behavior and for periods of time during these oscillations, ethanol production decreases substantially and there is considerable loss of residual substrates. There has been a considerable amount of work demonstrating oscillatory behavior in fermentation processes. The aim of this work is to demonstrate simple strategies to eliminate the oscillatory behavior in fermentation processes involving both Zymomonas mobilis and Saccharomyces cerevisiae. The oscillatory behavior is caused by the existence of Hopf bifurcations and it is demonstrated that very minor changes in the input conditions can eliminate the Hopf bifurcation points. In the case of Zymomonas
mobilis, it is shown that the addition of a small amount of substrate and/or the key component of the biomass and/or product in the input stream causes the disappearance of the Hopf bifurcation points while in Saccharomyces
cerevisiae fermentation process, a very minor increase in the input oxygen supply produces the same result. The aim of this work is not only to demonstrate the existence of the Hopf bifurcations in the fermentation problems, but also to provide strategies to eliminate them. © 2010 American Institute of Chemical Engineers AIChE J, 2011
Die Prins‐Makrocyclisierung als effiziente Ringschluss‐Strategie in der Naturstoffsynthese
Authors: Crane Erika A. , Scheidt Karl A.
Published: October 2010

Prins‐Makrocyclisierungen haben sich in jüngster Zeit als gute Methode für die Synthese natürlicher Polyketidderivate bewährt. Diese Reaktion stellt eine ökonomische und selektive Methode zur Bildung Tetrahydropyran‐haltiger Makrocyclen verschiedener Größe zur Verfügung und toleriert vielfältige funktionelle Gruppen im Makrocyclus, in der Regel bei guten bis ausgezeichneten Ausbeuten. Nach der erstmaligen Beschreibung der Prins‐Makrocyclisierung im Jahr 1979 wurde es still um diese Methode; erste Anwendungsbeispiele finden sich erst ab 2008. Der Einsatz dieser Methode in der Naturstoffsynthese hat bei Synthetikern seitdem immer mehr Interesse gefunden, und folgerichtig sind in der jüngeren Literatur zahlreiche Beispiele für Makrocyclisierungen dieses Typs beschrieben worden.
Prins‐Type Macrocyclizations as an Efficient Ring‐Closing Strategy in Natural Product Synthesis
Authors: Crane Erika A. , Scheidt Karl A.
Published: October 2010

Prins‐type macrocyclizations have recently emerged as a successful strategy in the synthesis of polyketide‐derived natural products. This reaction provides a concise and selective means to form tetrahydropyran‐containing macrocyclic rings of varying size. A high degree of functionality within the macrocycle is tolerated and the yields for these transformations are typically good to excellent. Since the initial report of a Prins macrocyclization reaction in 1979, examples of this approach did not re‐emerge until 2008. However, the use of this method in natural product synthesis has rapidly gained momentum in the synthetic community, with multiple examples of this macrocyclization tactic reported in the recent literature.
Optimum design of fluid distribution systems in heat exchangers
Authors: Turek Vojtěch , Hájek Jiří , Jegla Zdeněk , Stehlík Petr
Published: October 2010

Uniform flow distribution is often required by process equipment for its correct and reliable operation. Due to the fact that the resulting distribution is influenced by shapes of splitting and combining manifolds, flow distribution uniformity can be considerably increased by careful design. In case of high‐temperature applications, uniform flow distribution is usually crucial. The aim of this paper is to provide a formula for coefficient of static regain for parallel flow systems containing linearly tapered manifolds with rectangular cross sections connected by double U‐tubes. This formula was derived by means of approximating data obtained by evaluation of several baseline configurations of such distribution systems using fluid flow modelling software ANSYS® FLUENT®. Sample fluid distributions found using the proposed formula are shown alongside corresponding data computed by ANSYS FLUENT. Also, a practical computational tool for shape optimization of the investigated class of manifolds is presented. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
Modeling of ammonia conversion rate in ammonia synthesis based on a hybrid algorithm and least squares support vector regression
Authors: Xu Wei , Zhang Lingbo , Gu Xingsheng
Published: October 2010

In ammonia synthesis production, the ammonia conversion rate reflects how well the synthesis proceeds. In this paper, a model, which characterizes the relationship between operational variables and ammonia conversion rate, is established using least squares support vector regression (LSSVR). A hybrid algorithm of particle swarm optimization and differential evolution (HPSODE) is proposed to identify the hyperparameters of LSSVR, i.e. the regulation parameter and the width of the kernel function. HPSODE is first tested through benchmark functions and the performance is evaluated with traditional particle swarm optimization (PSO), differential evolution (DE), and a hybrid particle swarm optimization with differential evolution operator (DEPSO). It is then applied to the modeling of ammonia synthesis process. Results using other modeling methods [back propagation neural network (BPNN), LSSVR, PSO–LSSVR, and DE–LSSVR] are presented for comparison purpose. The proposed HPSODE–LSSVR modeling shows good feasibility of the algorithm and reliability of global convergence. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
Linear viscoelastic and morphological description of multiphase systems affected by processing parameters
Authors: Kuthanová Vanda , Hausnerová Berenika , Kitano Takeshi , Lapčíková Monika , Sáha Petr
Published: October 2010

Influence of processing methods, in terms of comparing compression and injection moldings, on the rheological behavior of polycarbonate (PC)/acrylonitrile‐butadiene‐styrene (ABS) blends and PC/ABS/glass fibers composites is presented. Blend compositions and fiber content are considered as material variables. For blends, the effect of the processing route on the viscoelastic functions is evident only for low shearing frequencies. Injection molding created morphology with cocontinuous character, while compression molded blends have “relaxed” structure, where dispersed phase domains are several times larger than in injection molded ones. The glass fiber reinforcement led to the significant differences in viscoelastic properties of composites processed by injection and compression molding. Injected composites have both moduli always higher than compression molded. Also, fiber lengths are reduced more for compressing molding. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Poly(acrylonitrile‐co‐methyl acrylate) copolymers: Correlation between copolymer composition, morphology and positron annihilation lifetime parameters
Authors: Zengeni E. , Hartmann P. C. , Sanderson R. D. , Mallon P. E.
Published: October 2010

A series of poly(acrylonitrile‐co‐methyl acrylate) copolymers of differing copolymer compositions are synthesized through free radical emulsion copolymerisation of methyl acrylate (MA) and acrylonitrile (AN) and by variation of the monomer feed ratios. The copolymers are characterized by NMR, SEC, WAXD, DMA, and positron annihilation lifetime spectroscopy. Results show that, there is a linear decrease in the glass transition temperature (Tg) of the copolymers and the MA content. There is also a progressive decrease in the crystallinity of the copolymers with increasing MA content. Positron results show a sigmoidal variation in the ortho positronium lifetime with an increasing MA content. The low MA content, semi‐crystalline copolymers show a positive deviation from the linear additive relationship between the o‐Ps lifetime and MA content, whereas the higher MA content amorphous copolymers show a negative deviation from the linear additive behavior. The o‐PS intensity shows a linear behavior with MA content with a slight deviation from the additive linear behavior for the very high‐content MA copolymer. These variations in the measured positron lifetime parameters are interpreted in terms of the copolymer morphology. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of hydrocarbon resin on the morphology and mechanical properties of isotactic polypropylene/clay composites
Authors: Cimmino Sossio , Silvestre Clara , Duraccio Donatella , Pezzuto Marilena
Published: October 2010

The article reports an investigation of the effect of a hydrocarbon resin, Necirés TR100, on the structure, morphology, and properties of two isotactic polypropylene/clay composites. The clays are Dellite HPS, a purified montmorillonite, and Dellite 67G, a purified and modified montmorillonite with a high content of quaternary ammonium salt. Necirés TR100 contains hydroxyl and acid groups, which were expected to interact during the melt mixing with the polar surface of the clays to have intercalation with Dellite HPS and/or exfoliation of Dellite 67G, which is already intercalated by the quaternary ammonium salt. The morphological results indicate that the composite isotactic polypropylene/Dellite HPS presents large and coarse clay domains, whereas the composite isotactic polypropylene/Dellite 67G presents a better distribution of the clay clusters, although the presence of some clay domains of a few μm are also detected. Although results from Wide Angle X‐ray Diffraction have indicated that Necirés TR100 has no effect on the layers distance of Dellite HPS and Dellite 67G its addition produces composites with clay particles homogenously distributed in the polyolefin matrix, better tensile properties (higher values of Young's modululs and elongation to break) and decrease of permeability. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Preparation, characterization, and application of NR/SBR/Organoclay nanocomposites in the tire industry
Authors: Shan Chunpeng , Gu Zheng , Wang Li , Li Peiyao , Song Guojun , Gao Zhenbin , Yang Xiaoyu
Published: October 2010

The natural rubber/styrene butadiene rubber/organoclay (NR/SBR/organoclay) nanocomposites were successfully prepared with different types of organoclay by direct compounding. The optimal type of organoclay was selected by the mechanical properties characterization of the NR/SBR/organoclay composites. The series of NR/SBR/organoclay (the optimal organoclay) nanocomposites were prepared with various organoclay contents loading from 1.0 to 7.0 parts per hundreds of rubber (phr). The nearly completely exfoliated organoclay nanocomposites with uniform dispersion were confirmed by transmission electron microscopy (TEM) and X‐ray diffraction (XRD). The results of mechanical properties measurement showed that the tensile strength, tensile modulus, and tear strength were improved significantly when the organoclay content was less than 5.0 phr. The tensile strength and the tear strength of the nanocomposite with only 3.0 phr organoclay were improved by 92.8% and 63.4%, respectively. It showed organoclay has excellent reinforcement effect with low content. The reduction of the score and cure times of the composites indicated that the organoclay acted as accelerator in the process of vulcanization. The incorporation of a small amount of organoclay greatly improved the swelling behavior and thermal stability, which was attributed to the good barrier properties of the dispersed organoclay layers. The outstanding performance of co‐reinforcement system with organoclay in the tire formulation showed that the organoclay had a good application prospect in the tire industry, especially for the improvement of abrasion resistance and the reduction of production cost. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Single polymeric bubble for the preparation of multiple micro/nano fibers
Authors: Ren Zhong‐Fu , He Ji‐Huan
Published: October 2010

Bubble‐electrospinning is suggested to produce micro/nano fibers. Contrary to classical electrospinning where a high voltage is applied to overcome the surface tension of the Taylor's cone, in bubble‐electrospinning, the voltage is applied to overcome the bubble's surface tension, which mainly depends upon the size of the bubble. Instead of single jet, millions of charged jets are observed simultaneously. In this article, we design a single bubble‐electrospinning to primarily study the effect of concentration on the spinning procedure. Polyvinylpyrrolidone (PVP) is used in the experiment. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Surface modification of linear low‐density polyethylene film by amphiphilic graft copolymers based on poly(higher α‐olefin)‐graft‐poly(ethylene glycol)
Authors: Fu Zhisheng , Liu Min , Xu Junting , Wang Qi , Fan Zhiqiang
Published: October 2010

In this article, a series of amphiphilic graft copolymers, namely poly(higher α‐olefin‐co‐para‐methylstyrene)‐graft‐poly(ethylene glycol), and poly(higher α‐olefin‐co‐acrylic acid)‐graft‐poly(ethylene glycol) was used as modifying agent to increase the wettability of the surface of linear low‐density polyethylene (LLDPE) film. The wettability of the surface of LLDPE film could be increased effectively by spin coating of the amphiphilic graft copolymers onto the surface of LLDPE film. The higher the content of poly(ethylene glycol) (PEG) segments, the lower the water contact angle was. The water contact angle of modified LLDPE films was reduced as low as 25°. However, the adhesion between the amphiphilic graft copolymer and LLDPE film was poor. To solve this problem, the modified LLDPE films coated by the amphiphilic graft copolymers were annealed at 110° for 12 h. During the period of annealing, heating made polymer chain move and rearrange quickly. When the film was cooled down, the alkyl group of higher α‐olefin units and LLDPE began to entangle and crystallize. Driven by crystallization, the PEG segments rearranged and enriched in the interface between the amphiphilic graft copolymer and air. By this surface modification method, the amphiphilic graft copolymer was fixed on the surface of LLDPE film. And the water contact angle was further reduced as low as 14.8°. The experimental results of this article demonstrate the potential pathway to provide an effective and durable anti‐fog LLDPE film. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of recrystallization on the molecular mobility of a copolymer of vinylidene fluoride and hexafluoropropylene
Authors: Kochervinskij Valentin V. , Malyshkina Inna A. , Bessonova Natalia P. , Suljanov Sergey N. , Dembo Kirill A.
Published: October 2010

Relaxation processes in copolymers of vinylidene fluoride with hexafluoropropylene (93/7) were studied by means of a dielectric method. The initial extruded film was recrystallized by free heating to temperatures above the melting point and by subsequent cooling. This increased both the perfection of the crystal phase and the degree of crystallinity. The impact of recrystallization on both the relaxation times (τ's) and the activation parameters of the local mobility (β process) and micro‐Brownian cooperative mobility in amorphous phase (αa process) was almost negligible, whereas the τ's of the αc relaxation were an order of magnitude higher after recrystallization. Qualitatively, it was predicted by the soliton model for the αc relaxation. The recrystallization affected characteristics of the transition at the highest temperature (α) registered in the region of the melting of the crystals even more. The process is related to the relaxation of the space charge formed by ionogenic impurities, which migrate through the amorphous phase with high free volume. It was shown that the dynamics in the amorphous phase controlled the drift mobility of free charge carriers and, by that, determined the τ of the space charge relaxation process. The structuring processes during the recrystallization also affected the parameters of the order–disorder transition in the low‐perfect ferroelectric (antiferroelectric) phase. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Structure, properties, and phase transitions of melt‐spun poly(vinylidene fluoride) fibers
Authors: Steinmann W. , Walter S. , Seide G. , Gries T. , Roth G. , Schubnell M.
Published: October 2010

Three different experimental techniques were used to study structural phase transitions in melt‐spun poly(vinylidene fluoride) fibers, which were produced with different process parameters and processed in the draw‐winding process at different temperatures and draw ratios. The fibers are examined with the help of wide‐angle X‐ray diffraction at elevated temperatures, differential scanning calorimetry with stochastic temperature modulation, and dynamic mechanical analysis. An oriented mesophase and deformed crystal structures can be observed in all fibers and assigned to the mechanical stress occurring in the processes. Furthermore, several phase transitions during melting and two mechanical relaxation processes could be detected. The observed transitions affect the crystal geometry, the orientation distribution, anisotropic thermal expansion, and the mechanic response of the fiber samples. The relaxation processes can be related with an increasing amount of crystalline β‐phase in fibers drawn at different temperatures. The detailed information about phase transitions and the related temperatures are used to produce fibers with an extended amount of β‐phase crystallites, which are responsible for piezoelectric properties of the material. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Co‐citation analysis, bibliographic coupling, and direct citation: Which citation approach represents the research front most accurately?
Authors: Boyack Kevin W. , Klavans Richard
Published: October 2010

In the past several years studies have started to appear comparing the accuracies of various science mapping approaches. These studies primarily compare the cluster solutions resulting from different similarity approaches, and give varying results. In this study we compare the accuracies of cluster solutions of a large corpus of 2,153,769 recent articles from the biomedical literature (2004–2008) using four similarity approaches: co‐citation analysis, bibliographic coupling, direct citation, and a bibliographic coupling‐based citation‐text hybrid approach. Each of the four approaches can be considered a way to represent the research front in biomedicine, and each is able to successfully cluster over 92% of the corpus. Accuracies are compared using two metrics—within‐cluster textual coherence as defined by the Jensen‐Shannon divergence, and a concentration measure based on the grant‐to‐article linkages indexed in MEDLINE. Of the three pure citation‐based approaches, bibliographic coupling slightly outperforms co‐citation analysis using both accuracy measures; direct citation is the least accurate mapping approach by far. The hybrid approach improves upon the bibliographic coupling results in all respects. We consider the results of this study to be robust given the very large size of the corpus, and the specificity of the accuracy measures used.
Apolipoprotein A‐IMilano anion exchange chromatography: Mass transfer and adsorption kinetics
Authors: Bankston Theresa E. , Carta Giorgio
Published: October 2010

The mass transfer and adsorption kinetics of self‐associating apolipoprotein A‐IMilano (apoA‐IM) was investigated for the two anion exchangers Q‐Sepharose‐HP and Macro‐Prep‐HQ. At high salt where no protein binding occurs and without urea, mass transfer was controlled by hindered pore diffusion of multiple associated forms for both materials. Adding urea suppressed self‐association, but resulted in higher viscosity and caused unfolding. As a consequence, the effective diffusivity decreased as urea was added and was greater for the larger pore Macro‐Prep‐HQ resin. At low salt, under strong binding conditions, the adsorption kinetics followed a more complex mechanism. In this case, the kinetics was very slow for both stationary phases up to 2 M urea. However, at higher urea concentrations, the adsorption kinetics for the smaller pore Q‐Sepharose‐HP matrix became much faster, suggesting a transition from pore‐ to surface‐dominated diffusion. Microscopic observations confirmed that different transport mechanisms were in play below and above 2 M urea, which marked the approximate boundary above which self‐association was suppressed and unfolding occurred. The net result was enhanced uptake kinetics at high urea concentrations (e.g., 4 M) where protein unfolding is thought to lead to a more flexible structure that can reptate along the pore surface. Although the observed enhancement was dependent on the pore size and, thus, the surface area of the resin, it was not limited to apoA‐IM. BSA showed a similar trend as a function of urea when its disulfide bonds were reduced.
Internal pudendal artery stenoses and erectile dysfunction: Correlation with angiographic coronary artery disease
Authors: Rogers Jason H. , Karimi Houshang , Kao John , Link Daniel , Javidan Javid , Yamasaki Dwayne S. , Dolan Mark , Laird John R. , Low Reginald I.
Published: October 2010

Objectives: To describe the angiographic characteristics of pelvic arterial disease in patients with erectile dysfunction (ED) nonresponsive to phosphodiesterase‐5 inhibitors (PDE5i) and suspected coronary artery disease (CAD). Background: ED and CAD share common risk factors which can result in endothelial dysfunction, atherosclerosis and flow‐limiting stenoses in the coronary and internal pudendal arteries. Methods: Ten patients undergoing cardiac catheterization with ED and a history of unsatisfactory response to a PDE5i were studied. ED severity was quantified using the International Index of ED scoring system. We performed angiography and quantitative vessel analysis of the coronary arteries, bilateral common and internal iliac arteries, and internal pudendal arteries (IPAs). Results: In this pilot observational study, we found a high correlation between the presence of angiographic CAD and IPA disease. The reference IPA diameters at the point of maximal stenosis were 2.7 ± 0.4 mm (right IPA) and 2.7 ± 0.5 mm (left IPA). In the nine patients with IPA disease, the average stenosis severity was 55 ± 31% (right) and 66% ± 25% (left), and average lesion length was 12.4 ± 5.2 mm (right) and 10.0 ± 3.5 mm (left). Four patients had unilateral IPA total occlusions, three of whom had moderate contralateral disease. The majority of IPA stenoses occurred in the mid to distal IPA and appears amenable to percutaneous revascularization. Conclusions: This represents the first angiographic report of CAD correlated with IPA disease in patients with ED. Further investigation is required to determine whether the development of macrovascular disease in the IPA causes ED and whether endovascular treatment is safe and effective in this population. © 2010 Wiley‐Liss, Inc.
Conformational studies on chiral rhodium complexes by ECD and VCD spectroscopy
Authors: Szilvágyi Gábor , Majer Zsuzsa , Vass Elemér , Hollósi Miklós
Published: October 2010

This article reports vibrational circular dichroism (VCD) and electronic circular dichroism (ECD) spectroscopic studies in acetonitrile on the chiral Rh2(O‐Phe‐Cbz)1(OAc)3 and Rh2(O‐Phe‐Ac)1(OAc)3 complexes (abbreviated Rh2Z1 and Rh2Ac1, respectively; Phe, L‐phenylalanine; Cbz, benzyloxycarbonyl; Ac, acetyl) supported by theoretical calculations. The ECD spectra of the complexes depend on temperature that indicates the conformational mobility of the chiral ligands. Calculations of the VCD spectra were performed at ab initio (DFT) level of theory using Gaussian 03 [B3LYP functional combined with the LANL2DZ basis set for the dirhodium core and the 6‐31G(d) basis set for other atoms]. The population‐weighted sums of the computed VCD spectra of the conformers are in excellent agreement with the experimental VCD spectra. The combination of the VCD and ECD spectroscopic methods led us to the structural characterization of the complexes. Chirality, 2011. © 2010 Wiley‐Liss, Inc.
Katalysatoren für die Sonnenenergie
Authors: Harrer Roswitha
Published: October 2010

Die Entwicklung der künstlichen Photosynthese und somit die mehr oder minder direkte Nutzung der Sonnenenergie ist seit Jahren ein zentrales Thema. Wie kann man Sonnenenergie billiger und besser zugänglich machen? Konkrete Empfehlungen für die zukünftige Forschung sprechen Wissenschaftler nach dem ersten Chemical Sciences and Society Symposium (CS3) zur Nutzung von Sonnenlicht aus.
Bakterien im Zahnbelag atmen Nitrat
Authors: Feil Sylvia
Published: October 2010

Im Meer wird jede Oberfläche besiedelt. So entstehen auf Schiffsrümpfen Biofilme und auch jedes Sandkorn im Meeressediment ist mit Bakterien besiedelt. Aber wie sieht es im menschlichen Körper aus? Die Mundhöhle zum Beispiel bietet Wärme und Feuchtigkeit, sodass viele Arten von Bakterien darin siedeln. Bremer Meeresbiologen haben nun Stickoxide im Zahnbelag gemessen und nachgewiesen, das diese durch aerobe denitrifizierende Bakterien gebildet werden.
Iris color and texture: A comparative analysis of real irises, ocular prostheses, and colored contact lenses
Authors: Herrera Jorge A. , Vilaseca Meritxell , Düll Jochen , Arjona Montserrat , Torrecilla Elena , Pujol Jaume
Published: October 2010

In this work, we analyzed the color and texture of irises, ocular prostheses, and cosmetic colored contact lenses measured by means of a multispectral system, which provides the CIE L*a*b* colorimetric coordinates of a high resolution image pixel by pixel. The same subject, who has dark brown irises, participated in the measurement of all the contact lenses. The CIE L*a*b* colorimetric coordinates were analyzed to classify the samples into three major groups (brown, blue and green) using a new algorithm developed for this purpose. This classification allowed us to carry out a comparison of the color associated with each set of samples, using the corresponding color gamuts in the CIE L*a*b* color space. Furthermore, we analyzed the iris color reproduction achieved by prostheses and contact lenses in terms of CIEDE2000 color differences, and obtained closer results with prostheses. In addition, we performed an analysis of texture by means of the color spatial distribution of all samples. This was achieved by means of two statistical approaches: first order statistics of image histograms and second order statistics using co‐occurrence matrices. The results suggest that the texture associated with real irises, ocular prostheses and colored contact lenses is very different. This study provides useful information about the color and texture of irises that may help to establish a strategy for improving the techniques used in the manufacturing process of prostheses and colored contact lenses to obtain a better and more realistic appearance. © 2010 Wiley Periodicals, Inc. Col Res Appl, 2011
P‐GRADE portal family for grid infrastructures
Authors: Kacsuk Peter
Published: October 2010

P‐GRADE portal is one of the most widely used general‐purpose grid portal in Europe. The paper summarizes the most advanced features of P‐GRADE, such as parameter sweep workflow execution, multi‐grid workflow execution and integration with the DSpace workflow repository. It also shows the NGS P‐GRADE portal that extends P‐GRADE with the GEMLCA legacy code execution support in Grid systems, as well as with coarse‐grain workflow interoperability services. Next, the paper introduces the second generation P‐GRADE portal called WS‐PGRADE that merges the advanced features of the first generation P‐GRADE portals and extends them with new workflow and architecture concepts. Finally, the application‐specific science gateway of the CancerGrid project is briefly described to demonstrate that application‐specific portals can easily be developed on top of the general‐purpose WS‐PGRADE portal. Copyright © 2010 John Wiley & Sons, Ltd.
Diffusiophoresis of an Elongated Cylindrical Nanoparticle along the Axis of a Nanopore
Authors: Joo Sang W. , Lee Sang Yoon , Liu Jing , Qian Shizhi
Published: October 2010

The translation of a charged, elongated cylindrical nanoparticle along the axis of a nanopore driven by an imposed axial salt concentration gradient is investigated using a continuum theory, which consists of the ionic mass conservation equations for the ionic concentrations, the Poisson equation for the electric potential in the solution, and the modified Stokes equations for the hydrodynamic field. The diffusiophoretic motion is driven by the induced electrophoresis and chemiphoresis. The former is driven by the generated overall electric field arising from the difference in the ionic diffusivities and the double layer polarization, while the latter is generated by the induced osmotic pressure gradient around the charged particle. The induced diffusiophoretic motion is investigated as functions of the imposed salt concentration gradient, the ratio of the particle’s radius to the double layer thickness, the cylinder’s aspect ratio (length/radius), the ratio of the nanopore size to the particle size, the surface charge densities of the nanoparticle and the nanopore, and the type of the salt used. The induced diffusiophoretic motion of a nanorod in an uncharged nanopore is mainly governed by the induced electrophoresis, driven by the induced electric field arising from the double layer polarization. The induced particle motion is driven by the induced electroosmotic flow, if the charges of the nanorod and nanopore wall have the same sign.
Performance analysis for V‐BLAST system using OSIC receiver in correlated channel
Authors: Feng Xingle , Sun Zhaoyun , Yang Xiaojun , Liu Long
Published: October 2010

Vertical‐Bell Labs Layered Space–Time (V‐BLAST) system is an emerging spatial multiplexing scheme that can achieve high spectral efficiency. Ordered successive interference cancellation (OSIC) detection algorithm is suitable for V‐BLAST system because it can afford a reasonable trade‐off between complexity and performance. However, the correlation of a real‐world wireless channel may result in a substantial degradation of the OSIC performance. In this paper, the performance of OSIC under correlated fading is analyzed. We obtain the closed‐form expression of post‐processing signal‐to‐noise ratio (SNR) for each sub‐stream based on V‐BLAST architecture, and then derive the distribution of post‐processing SNR based on multivariate statistical theory. The upper bound of the average probability of error (APE) is derived by the nearest neighbor union bound theory. From the expression of APE for each sub‐stream, it is shown that the diversity gain at theith processing step is (N−M+i), whereNandMare the number of receive and transmit antennas, respectively. Correlation can decrease the effective post‐processing SNR rather than the diversity gain, and the decreased amount of the effective post‐processing SNR is accurately measured by the corresponding diagonal element of the inverse of the transmit correlation matrix. The optimal ordering can improve the performance and this advantage vanishes gradually as the scattering angle decreases. Copyright © 2010 John Wiley & Sons, Ltd.
Dermoskeleton morphogenesis in zebrafish fins
Authors: Marí‐Beffa Manuel , Murciano Carmen
Published: October 2010

Zebrafish fins have a proximal skeleton of endochondral bones and a distal skeleton of dermal bones. Recent experimental and genetic studies are discovering mechanisms to control fin skeleton morphogenesis. Whereas the endochondral skeleton has been extensively studied, the formation of the dermal skeleton requires further revision. The shape of the dermal skeleton of the fin is generated in its distal growing margin and along a proximal growing domain. In these positions, dermoskeletal fin morphogenesis can be explained by intertissue interactions and the function of several genetic pathways. These pathways regulate patterning, size, and cell differentiation along three axes. Finally, a common genetic control of late development, regeneration, and tissue homeostasis of the fin dermoskeleton is currently being analyzed. These pathways may be responsible for the similar shape obtained after each morphogenetic process. This provides an interesting conceptual framework for future studies on this topic. Developmental Dynamics 239:2779–2794, 2010. © 2010 Wiley‐Liss, Inc.
Transitin is required for the differentiation of avian QM7 myoblasts into myotubes
Authors: Jalouli Maroua , Lapierre Louis R. , Guérette Dominique , Blais Karine , Lee Ju‐Ahng , Cole Gregory J. , Vincent Michel
Published: October 2010

Transitin is a nestin‐like intermediate filament protein co‐expressed with vimentin in the precursor cells of the myogenic and neurogenic lineages of the avian embryo. To understand its role in myogenesis, stable cell lines expressing transitin‐targeted siRNAs were derived from the quail muscle cell line QM7. When cells were cultured in differentiation medium, we found that transitin knockdown prevented myoblast fusion and myotube formation. MyoD mRNA could be detected in transitin siRNA‐transfected cells, but upregulation of myogenin and desmin expression was impaired compared to control cells. In addition, transitin siRNA cells maintain high levels of Pax7 expression suggesting that QM7 myoblasts into which transitin expression has been attenuated display a muscle progenitor cell phenotype (Pax7+/MyoD+/myogenin−/desmin−). These observations indicate that transitin plays an important role in the initiation of the myogenic program in avian muscle progenitor cells in acting downstream of MyoD and upstream of myogenin during the lineage progression. © 2010 Wiley‐Liss, Inc. Developmental Dynamics 239:3038–3047, 2010. © 2010 Wiley‐Liss, Inc.
Summary of ‘Regular treatment with formoterol and inhaled steroids for chronic asthma: serious adverse events’
Authors: Office Evidence‐Based Child Health Editorial
Published: October 2010

This is a summary of a Cochrane review, published in this issue of EBCH, first published as: Cates CJ, Lasserson TJ, Jaeschke R. Regular treatment with formoterol and inhaled steroids for chronic asthma: serious adverse events. Cochrane Database of Systematic Reviews 2009, Issue 2. Art. No.: CD006924. DOI: 10.1002/14 651 858.CD006924.pub2.

Further information for this Cochrane review is available in this issue of EBCH in the accompanying Commentary. Copyright © 2010 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. The Cochrane Collaboration
The Cochrane Library and the Treatment of Chronic Cough in Children: An Overview of Reviews
Authors: Russell Kelly , Chang Anne B. , Foisy Michelle , Thomson Denise , Williams Katrina
Published: October 2010

Background

Chronic cough is a universal condition of childhood that affects approximately one in ten children. Chronic cough can be either specific (‘wet’ cough or other symptoms concurrently present) or nonspecific (‘dry’ cough in the absence of other symptoms). Compared to adults, specific and non‐specific chronic cough in children differs in terms of both aetiology and treatment, and the methods used to treat chronic cough in adults may actually be harmful for children.

Objective

This overview of reviews synthesizes the evidence currently in the Cochrane Library Database of Systematic Reviews (CDSR) in order to answer the following question: in the treatment of childhood specific and non‐specific chronic cough, which pharmacologic or non‐pharmacologic treatments improve cough symptoms and decrease adverse events?

Methods

The Cochrane Database of Systematic Reviews was searched using the terms ‘specific cough’, ‘non‐specific cough’, ‘moist cough’ and ‘chronic cough’ in the record title for all systematic reviews examining pharmacologic or non‐pharmacologic interventions for the treatment of chronic cough in children. Data were extracted, complied into tables, and synthesized using qualitative and quantitative methods.

Main Results

Six reviews (five on non‐specific cough and one on specific cough) were indentified for inclusion. For non‐specific cough, one review found that very high‐dose inhaled corticosteroids were effective in reducing non‐specific cough (RR: 2.04; 95% CI: 1.10, 3.77), but this treatment was not advocated. To date, there is no evidence that anti‐histamines, β2 agonists, gastro‐oesophageal reflux treatments or leukotriene receptor antagonists are efficacious for the treatment of non‐specific chronic cough. For specific cough related to isolated wet cough, there was significant clinical improvement when children were treated with antibiotics (RR: 2.42; 95% CI: 1.65, 3.53). Limited data were available for adverse events associated with any of the treatment options.

Authors' Conclusions

The paucity of RCT evidence in the management of children with chronic cough is striking. Five systematic reviews on interventions for non‐specific cough do not support an empirical treatment approach. One systematic review on interventions for specific cough found some support for the use of antibiotics. Copyright © 2010 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. The Cochrane Collaboration
Anxiety above the clouds
Authors: Moja Lorenzo
Published: October 2010

These are the answers to the Dr Cochrane vignette on pages 1192–1195. How did you get on? Register your score at ebch@wiley.com. Copyright © 2010 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. The Cochrane Collaboration
Evapotranspiration of mixed shrub communities in phreatophytic zones of the Great Basin region of Nevada (USA)
Authors: Devitt D. A. , Fenstermaker L. F. , Young M. H. , Conrad B. , Baghzouz M. , Bird B. M.
Published: October 2010

In this study, evapotranspiration (ET) was estimated for three valleys (White River, Spring Valley and Snake Valley) in the Great Basin region of Nevada (USA) during a 3‐year period. ET estimates were based on an energy balance approach using the eddy covariance (EC) method and were scaled to the basin level by developing empirical relationships between ET and remotely sensed spectral data (Landsat). Annual EC–ET values for the three basins and previously published values attained for the same valleys during the same time period were correlated to average normalized difference vegetation index (NDVI) values for the growing period. Resulting empirical relationships accounted for 97% (p < 0·001) of the variation in the EC–ET estimate for the 10 May–5 September growing period, and 93% (p < 0·001) of the variation in the EC–ET estimates based on measured or projected yearly ET totals.

Variations in yearly ET estimates at the different shrubland sites ranged from 20 to 50 cm during the two dry years (2006 and 2007, not including the irrigated site). Winter precipitation was shown to be a significant driving force in the physiological response of the plants and the yearly ET totals. In the case of White River Valley, the ratio of winter precipitation to reference evapotranspiration (ETref) declined from 79 to 11% over the 3‐year monitoring period. Overall, ET rates in 2007 (May–Sept.) were highly correlated with the percentage cover of greasewood at the monitoring sites (R2 = 0·96***), regardless of the depth to groundwater. Copyright © 2010 John Wiley & Sons, Ltd.
Functionalization of (2S)‐Isopropyl‐5‐iodo‐2,3‐dihydro‐4(H)‐pyrimidin‐4‐ones by a Suzuki–Miyaura Cross‐Coupling Reaction Using Aryltrifluoroborate Salts: Convenient Enantioselective Preparation of α‐Substituted β‐Amino Acids
Authors: Stefani Hélio A. , Amaral Monica F. Z. J. , Reyes‐Rangel Gloria , Vargas‐Caporali Jorge , Juaristi Eusebio
Published: October 2010

A simple protocol for the Pd(OAc)2‐catalyzed cross‐coupling reaction of 1‐benzoyl‐(2S)‐isopropyl‐5‐iodo‐2,3‐dihydro‐4(H)‐pyrimidin‐4‐ones with potassium aryltrifluoroborates was developed. The reaction is performed at 110 °C with a ligand‐free catalyst. In all cases, complete conversion of the 1‐benzoyl‐(2S)‐isopropyl‐5‐iodo‐2,3‐dihydro‐4(H)‐pyrimidin‐4‐onesand aryltrifluoroborates into the C–C coupling products was observed within 30–360 min. It is noteworthy that a largevariety of groups present in the potassium aryltrifluoroborates (–CF3, –OMe, –SEt, –CN, –CHO, –Cl, –Cbz, –NCbz,–OH, –CO2H) could be tolerated. Hydrogenation of the endocyclic double bonds in the Suzuki–Miyaura products followed by acid hydrolysis afforded highly enantioenrichedα‐aryl‐substituted β‐amino acids.
Acetic acid denaturing pulsed field capillary electrophoresis for RNA separation
Authors: Li Zhenqing , Dou Xiaoming , Ni Yi , Sumitomo Keiko , Yamaguchi Yoshinori
Published: October 2010

Based on our previous work of in‐capillary denaturing polymer electrophoresis, we present a study of RNA molecular separation up to 6.0 kilo nucleotide by pulsed field CE. This is the first systematic investigation of electrophoresis of a larger molecular mass RNA in linear hydroxyethylcellulose (HEC) under pulsed field conditions. The parameters that may influence the separation performance, e.g. gel polymer concentration, modulation depth and pulse frequency, are analyzed in terms of resolution and mobility. For denaturing and separating RNA in the capillary simultaneously, 2 M acetic acid was added into the HEC polymer to serve as separation buffer. Result shows that (i) in pulsed field conditions, RNA separation can be achieved in a wide range of concentration of HEC polymer, and RNA fragments between 0.3 and 0.6 kilo nucleotide are sensitive to the polymer concentration; (ii) under certain pulsed field conditions, RNA fragments move linearly as the modulation depth increases; (iii) 12.5 Hz is the resonance frequency for RNA reorientation time and applied frequency.
Biosystems analysis and engineering of microbial consortia for industrial biotechnology
Authors: Sabra Wael , Dietz David , Tjahjasari Donna , Zeng An‐Ping
Published: October 2010

The development of industrial biotechnology for an economical and ecological conversion of renewable materials into chemicals and fuels requires new strategies and concepts for bioprocessing. Biorefinery has been proposed as one of the key concepts with the aim of completely utilizing the substrate(s) and producing multiple products in one process or at one production site. In this article, we argue that microbial consortia can play an essential role to this end. To illustrate this, we first briefly describe some examples of existing industrial bioprocesses involving microbial consortia. New bioprocesses under development which make use of the advantages of microbial consortia are then introduced. Finally, we address some of the key issues and challenges for the analysis and engineering of bioprocesses involving microbial consortia from a perspective of biosystems engineering.
Isomer-specific accumulation of perfluorooctane sulfonate in the liver of chicken embryos exposed in ovo to a technical mixture
Authors: O'Brien Jason M , Kennedy Sean W , Chu Shaogang , Letcher Robert J
Published: October 2010

Prior to its recent phaseout, perfluorooctane sulfonate (PFOS) was produced by electrochemical fluorination processes, which yielded technical mixtures composed of linear isomer (∼65–79%) and several branched isomers (∼21–35%). Because PFOS can biomagnify in wildlife, birds that occupy higher trophic levels are at increased risk of exposure. We hypothesized that the pharmacokinetic properties of PFOS are isomer-specific in developing chicken (Gallus gallus domesticus) embryos exposed to technical grade PFOS (T-PFOS). In the present study, T-PFOS was composed of 62.7% linear isomer (L-PFOS), and 37.3% branched isomer, including six mono(trifluoromethyl)-branched isomers and four bis(trifluoromethyl)-branched isomers. Concentrations of 0.1, 5, or 100 µg/g of T-PFOS were injected into the air cell of chicken eggs prior to incubation. After pipping, compared with T-PFOS, the PFOS isomer profile in embryonic liver tissue for the 0.1 µg/g dose group showed 21% enrichment in the proportion of L-PFOS with a corresponding decrease in the proportion of branched isomers. Not all branched isomers were discriminated against at equal rates. The proportion of two mono(trifluoromethyl)-branched isomers and three bis(trifluoromethyl)-branched isomers decreased to a greater degree than other branched isomers. In contrast, the mono-branched isomer, P6MHpS, was overrepresented in the low-dose group. In the higher dose groups, L-PFOS was still enriched but only by approximately 10%, which indicated a dose-dependent change in isomer composition relative to T-PFOS. These results show that accumulation of PFOS in chicken embryo livers is dependent on the presence and position of branches on the alkyl backbone. This supports the hypothesis that the pharmacokinetics of PFOS are isomer-specific in biota, and may help explain why wildlife PFOS burdens are dominated by L-PFOS relative to T-PFOS mixtures. Environ. Toxicol. Chem. 2011;30:226–231. © 2010 SETAC
mRNA Expression and activity of ion-transporting proteins in gills of the blue crab Callinectes sapidus: Effects of waterborne copper
Authors: Martins Camila M. G , Almeida Daniela Volcan , Marins Luis Fernando Fernandes , Bianchini Adalto
Published: October 2010

Waterborne Cu effects on the transcription of genes encoding ion-transporting proteins and the activities of these proteins were evaluated in gills of the blue crab Callinectes sapidus acclimated to diluted (2‰) and full (30‰) seawater. Crabs were exposed (96 h) to an environmentally relevant concentration of dissolved Cu (0.78 µM) and had their posterior (osmoregulating) gills dissected for enzymatic and molecular analysis. Endpoints analyzed were the activity of key enzymes involved in crab osmoregulation (sodium-potassium adenosine triphosphatase [Na+/K+-ATPase], hydrogen adenosine triphosphatase [H+-ATPase], and carbonic anhydrase [CA]) and the mRNA expression of genes encoding these enzymes and the sodium-potassium-chloride (Na+/K+/2Cl−) cotransporter. Copper effects were observed only in crabs acclimated to diluted seawater (hyperosmoregulating crabs) and were associated with an inhibition of the expression of mRNA of genes encoding the Na+/K+-ATPase and the Na+/K+/2Cl− cotransporter. However, Cu did not affect Na+/K+-ATPase activity, indicating that the gene transcription is downregulated before a significant inhibition of the enzyme activity can be observed. This also suggests the existence of a compensatory response of this enzyme to prevent osmoregulatory disturbances after short-term exposure to environmentally relevant Cu concentrations. These findings suggest that Cu is a potential ionoregulatory toxicant in blue crabs C. sapidus acclimated to low salinity. The lack of Cu effect on blue crabs acclimated to full seawater would be due to the reduced ion uptake needed for the regulation of the hemolymph osmotic concentration in full seawater (30‰). Also, this could be explained considering the lower bioavailability of toxic Cu (free ion) associated with the higher ionic content and dissolved organic matter concentration in high salinity (30‰) than in diluted seawater (2‰). Environ. Toxicol. Chem. 2011;30:206–211. © 2010 SETAC