bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variants of folate metabolism genes and risk of left‐sided cardiac defects
Authors: Mitchell Laura E. , Long Jin , Garbarini Jennifer , Paluru Prasuna , Goldmuntz Elizabeth 
Published: September 2009

AbstractBACKGROUND:Congenital heart defects (CHDs) are the most common, serious group of birth defects. Although relatively little is known about the causes of these conditions and there are no established prevention strategies, evidence suggests that the risk of CHDs may be related to maternal folate status as well as genetic variants in folate‐related genes. Efforts to establish the relationships between these factors and CHD risk have, however, been hampered by a number of factors, including small study sample sizes and phenotypic heterogeneity.METHODS:The present study examined the relationship between nine genetic variants in eight folate‐related genes and a relatively homogeneous group of left‐sided cardiac defects in a cohort of 386 case‐parent triads. Log‐linear analyses were used to assess both maternal and inherited genetic effects.RESULTS:Analyses of the study data provided marginal evidence that the maternalMTRA2756G (unadjustedp= 0.01) and the inheritedBHMTG742A (unadjustedp= 0.06) genotypes influence the risk of this subset of CHDs. However, neither association achieved significance when the false‐discovery rate was controlled at 0.05.CONCLUSIONS:These results, which are based on the largest study sample and most comprehensive assessment of the relationship between left‐sided cardiac defects and folate‐related genes reported to date, provide little evidence that this subset of CHDs is folate related. However, even larger studies and more comprehensive evaluations of the folate pathway genes are required to fully explore the relationship between folate and left‐sided cardiac defects. Birth Defects Research (Part A) 2010. © 2009 Wiley‐Liss, Inc.
Metabolic flux analysis for recombinant protein production by Pichia pastoris using dual carbon sources: Effects of methanol feeding rate
Authors: Çelik Eda , Çalık Pınar , Oliver Stephen G. 
Published: September 2009

AbstractThe intracellular metabolic fluxes through the central carbon pathways in the bioprocess for recombinant human erythropoietin (rHuEPO) production by Pichia pastoris (Mut+) were calculated to investigate the metabolic effects of dual carbon sources (methanol/sorbitol) and the methanol feed rate, and to obtain a deeper understanding of the regulatory circuitry of P. pastoris, using the established stoichiometry‐based model containing 102 metabolites and 141 reaction fluxes. Four fed‐batch operations with (MS‐) and without (M‐) sorbitol were performed at three different constant specific growth rates (h−1), and denoted as M‐0.03, MS‐0.02, MS‐0.03, and MS‐0.04. Considering the methanol consumption pathway, the M‐0.03 and MS‐0.02 conditions produced similar effects and had >85% of formaldehyde flux towards the assimilatory pathway. In contrast, the use of the dual carbon source condition generated a shift in metabolism towards the dissimilatory pathway that corresponded to the shift in dilution rate from MS‐0.03 to MS‐0.04, indicating that the methanol feed exceeded the metabolic requirements at the higher µ0. Comparing M‐0.03 and MS‐0.03 conditions, which had the same methanol feeding rates, sorbitol addition increased the rHuEPO synthetic flux 4.4‐fold. The glycolysis, gluconeogenesis, and PPP pathways worked uninterruptedly only at MS‐0.02 condition. PPP and TCA cycles worked with the highest disturbances at MS‐0.04 condition, which shows the stress of increased feeding rates of methanol on cell metabolism. Biotechnol. Bioeng. 2010; 105: 317–329. © 2009 Wiley Periodicals, Inc.
High stability of self‐assembled peptide nanowires against thermal, chemical, and proteolytic attacks
Authors: Ryu Jungki , Park Chan Beum 
Published: September 2009

AbstractUnderstanding the self‐assembly of peptides into ordered nanostructures is recently getting much attention since it can provide an alternative route for fabricating novel bio‐inspired materials. In order to realize the potential of the peptide‐based nanofabrication technology, however, more information is needed regarding the integrity or stability of peptide nanostructures under the process conditions encountered in their applications. In this study, we investigated the stability of self‐assembled peptide nanowires (PNWs) and nanotubes (PNTs) against thermal, chemical, proteolytic attacks, and their conformational changes upon heat treatment. PNWs and PNTs were grown by the self‐assembly of diphenylalanine (Phe–Phe), a peptide building block, on solid substrates at different chemical atmospheres and temperatures. The incubation of diphenylalanine under aniline vapor at 150°C led to the formation of PNWs, while its incubation with water vapor at 25°C produced PNTs. We analyzed the stability of peptide nanostructures using multiple tools, such as electron microscopy, thermal analysis tools, circular dichroism, and Fourier‐transform infrared spectroscopy. Our results show that PNWs are highly stable up to 200°C and remain unchanged when incubated in aqueous solutions (from pH 1 to 14) or in various chemical solvents (from polar to non‐polar). In contrast, PNTs started to disintegrate even at 100°C and underwent a conformational change at an elevated temperature. When we further studied their resistance to a proteolytic environment, we discovered that PNWs kept their initial structure while PNTs fully disintegrated. We found that the high stability of PNWs originates from their predominant β‐sheet conformation and the conformational change of diphenylalanine nanostructures. Our study suggests that self‐assembled PNWs are suitable for future nano‐scale applications requiring harsh processing conditions. Biotechnol. Bioeng. 2010; 105: 221–230. © 2009 Wiley Periodicals, Inc.
High‐throughput microarray profiling of cell wall polymers during hydrothermal pre‐treatment of wheat straw
Authors: Alonso‐Simón Ana , Kristensen Jan Bach , Øbro Jens , Felby Claus , Willats William G.T. , Jørgensen Henning 
Published: September 2009

AbstractLignocellulosic plant material is potentially a sustainable source of fermentable sugars for bioethanol production. However, a barrier to this is the high resistance or recalcitrance of plant cell walls to be hydrolyzed. Therefore, a detailed knowledge of the structural features of plant cell walls that contribute to recalcitrance is important for improving the efficiency of bioethanol production. In this work we have used a technique known as Comprehensive Microarray Polymer Profiling (CoMPP) to analyze wheat straw before and after being subjected to hydrothermal pre‐treatments at four different temperatures. The CoMPP technique combines the specificity of monoclonal antibodies with the high‐throughput capacity of microarrays. Changes in the relative abundance of cell wall polysaccharides could be tracked during processing, and a reduction in xylan, arabinoxylans, xyloglucan, and mixed‐linked glucan epitopes was detected at the two highest temperatures of pre‐treatment used. This work demonstrates the potential of CoMPP as a complementally technique to conventional methods for analyzing biomass composition. Biotechnol. Bioeng. 2010; 105: 509–514. © 2009 Wiley Periodicals, Inc.
Surface‐directed assembly of cell‐laden microgels
Authors: Du Yanan , Ghodousi Majid , Lo Edward , Vidula Mahesh K. , Emiroglu Onur , Khademhosseini Ali 
Published: September 2009

AbstractCell‐laden microscale hydrogels (microgels) can be used as tissue building blocks and assembled to create 3D tissue constructs with well‐defined microarchitecture. In this article, we present a bottom‐up approach to achieve microgel assembly on a patterned surface. Driven by surface tension, the hydrophilic microgels can be assembled into well‐defined shapes on a glass surface patterned with hydrophobic and hydrophilic regions. We found that the cuboidic microgels (∼100–200 µm in width) could self‐assemble into defined shapes with high fidelity to the surface patterns. The microgel assembly process was improved by increasing the hydrophilicity of the microgels and reducing the surface tension of the surrounding solution. The assembled microgels were stabilized by a secondary crosslinking step. Assembled microgels containing cells stained with different dyes were fabricated to demonstrate the application of this approach for engineering microscale tissue constructs containing multiple cell types. This bottom‐up approach enables rapid fabrication of cell‐laden microgel assemblies with pre‐defined geometrical and biological features, which is easily scalable and can be potentially used in microscale tissue engineering applications. Biotechnol. Bioeng. 2010; 105: 655–662. © 2009 Wiley Periodicals, Inc.
A Study on Glutaric Acid Extraction by Tridodecylamine: Equilibria and Models
Authors: Uslu H. , Inci I. 
Published: September 2009

AbstractThe extraction of glutaric acid was studied using tridodecyl amine (TDA) with respect to the functional groups of the diluent. The diluents studied were 1‐octanol (alcohol), methyl isobuthyl ketone, MIBK (ketone), and toluene (aromatic hydrocarbon) and these were used to dilute the TDA. The experimental results of batch extraction experiments are reported as distribution coefficients, DC, loading factors, Z, and extraction efficiency, E. All measurements were carried out at 298.15 K. The results of the liquid‐liquid equilibrium measurements are correlated by a linear solvation energy relationship (LSER) model that takes into account physical interactions and modified Freundlich and Langmuir equations. The experimental results are compared with model results.
Evaluation of Mass Transfer Coefficients in Biotrickling Filters: Experimental Determination and Comparison to Correlations
Authors: Dorado A. D. , Rodríguez G. , Ribera G. , Bonsfills A. , Gabriel D. , Lafuente J. , Gamisans X. 
Published: September 2009

AbstractOverall mass transfer coefficients (KGa and KLa) were determined experimentally for four different‐nature packing materials used in gas‐phase biotrickling filters. A simple methodology based on overall mass balances and following a standard procedure allowed to calculate the mass transfer coefficients under different operating conditions corresponding to usual biotrickling filtration situations. Results showed an increase of mass transfer resistance when increasing the empty bed residence time (EBRT) of the reactor for all packing materials. Experimental results were fitted to existing and well‐accepted correlations used in conventional biofilter or biotrickling filter modeling. The comparison of experimental and theoretical data showed huge discrepancies. Simple correlations for the experimental data obtained in this study were also suggested.
Xanthones and Oxepino[2, 3‐b]chromones from Three Endophytic Fungi
Authors: Krohn Karsten , Kouam Simeon F. , Kuigoua Guy M. , Hussain Hidayat , Cludius‐Brandt Stephan , Flörke Ulrich , Kurtán Tibor , Pescitelli Gennaro , Di Bari Lorenzo , Draeger Siegfried , Schulz Barbara 
Published: September 2009

AbstractThree new metabolites, microsphaeropsones A–C (1–3) with a unique oxepino[2,3‐b]chromen‐6‐one (ring‐enlarged xanthone) skeleton, were isolated from the endophytic fungus Microsphaeropsis species, co‐occurring with their putative biogenetic anthraquinoide precursors citreorosein (4) and emodin (5). From another Microsphaeropsis species, large amounts of fusidienol A (8 a), smaller amounts of emodin (5), the known aromatic xanthones 9 a and 9 b, the new 3,4‐dihydrofusidienol A (8 b), and the new aromatic xanthone 9 c were isolated. The endophyte Seimatosporium species produced a new aromatic xanthone, seimatoxanthone A (10), and 3,4‐dihydroglobosuxanthone A (12), closely related to α‐diversolonic ester (13) from Microdiplodia sp.. The structures were determined mainly by extensive 1D and 2D NMR experiments and supported by X‐ray single‐crystal analysis of 1 and the oxidation product 7. The absolute configurations of the microsphaeropsones A–C (1–3) were established by comparison of the electronic and vibrational circular dichroism (ECD and VCD) spectra of 1 with time‐dependent DFT (TDDFT) and DFT calculations by using either the solid‐state structures or DFT‐optimized geometries as inputs. Preliminary studies indicated that 1, 2, and enone 7 showed antibacterial, fungicidal, and algicidal properties.
Ionic Liquids as Performance Additives for Electroenzymatic Syntheses
Authors: Kohlmann Christina , Greiner Lasse , Leitner Walter , Wandrey Christian , Lütz Stephan 
Published: September 2009

AbstractElectroenzymatic syntheses combine oxidoreductase‐catalysed reactions with electrochemical reactant supply. The use of ionic liquids as performance additives can contribute to overcoming existing limitations of these syntheses. Here, we report on the influence of different water‐miscible ionic liquids on critical parameters such as conductivity, biocatalyst activity and stability or substrate solubility for three typical electroenzymatic syntheses. In these investigations promising ionic liquids were identified and have been used as additives for batch electrolyses on preparative scale for the three electroenzymatic systems. It was possible to improve the space‐time‐yield for the electrochemical regeneration of NADPH by a factor of three. For an amino acid oxidase catalysed resolution of a methionine racemate with ferrocene‐mediated electrochemical regeneration of the enzyme‐bound cofactor FAD a 50 % increase in space time yield and 140 % increase in catalyst utilisation (TTN) were achieved. Furthermore, for the chloroperoxidase‐catalysed synthesis of (R)‐phenylmethylsulfoxide with electrochemical generation of the required cosubstrate H2O2 the space time yield and the catalyst utilisation were improved by a factor of up to 4.2 depending on the ionic liquids used.
Condensation of β‐Diester Titanium Enolates with Carbonyl Substrates: A Combined DFT and Experimental Investigation
Authors: Marrone Alessandro , Renzetti Andrea , De Maria Paolo , Gérard Stéphane , Sapi Janos , Fontana Antonella , Re Nazzareno 
Published: September 2009

AbstractThe condensation of dialkyl β‐diesters with various aldehydes promoted by TiCl4 has been studied by DFT approaches and experimental methods, including NMR, IR and UV/Vis spectroscopy. Various possible reaction pathways have been investigated and their energy profiles evaluated to find out a plausible mechanism of the reaction. Theoretical results and experimental evidence point to a three‐step mechanism: 1) Ti‐induced formation of the enolate ion; 2) aldol reaction between the enolate ion and the aldehyde, both coordinated to titanium; and 3) intramolecular elimination that leads to a titanyl complex. The presented mechanistic hypothesis allows one to better understand the pivotal role of titanium(IV) in the reaction.
Oligomeric Tectonics: Supramolecular Assembly of Double‐Stranded Oligobisnorbornene through π–π Stacking
Authors: Lee Shern‐Long , Lin Nai‐Ti , Liao Wei‐Chih , Chen Chun‐hsien , Yang Hsiao‐Ching , Luh Tien‐Yau 
Published: September 2009

AbstractSelf‐assembly at the molecular level in solutions or on a surface is a subject of current interest. Herein we describe the tailoring of oligobisnorbornene 1, which represents an innovative concept of a preorganized building block on the tens of nanometer scale. The rodlike 1 has vinyl and styrenyl end groups. Scanning tunneling microscopy (STM) reveals that the oligomers aggregate anisotropically along the long axis and form a one‐dimensional assembly in which, remarkably, no interstitial gap appears between neighboring oligomers. Dynamic light‐scattering (DLS) measurements indicate that the assembly develops in solution. With a shear treatment for dropcast films, a unidirectionally ordered domain with a defect density less than 0.5 % can be prepared. Simulation results by molecular dynamics suggest that there may be multiple interactions such as π–π stacking and dipolar attractions taking place between the termini of the oligomers. To demonstrate the importance of double bonds in the oligomeric backbones and termini towards the tectonic assembly, a hydrogenated analogue was synthesized; π–π interactions are thus less significant and the film morphology is completely different from that of 1. This work extends the concept of molecular tectonics to preorganized oligomers and opens up a new avenue of nanopatterning toward nanodevices.
The 3[ndσ*(n+1)pσ] Emissions of Linear Silver(I) and Gold(I) Chains with Bridging Phosphine Ligands
Authors: Tong Glenna So Ming , Kui Steven Chi Fai , Chao Hsiu‐Yi , Zhu Nianyong , Che Chi‐Ming 
Published: September 2009

AbstractThe complexes [Au3(dcmp)2][X]3 {dcmp=bis(dicyclohexylphosphinomethyl)cyclohexylphosphine; X=Cl− (1), ClO4− (2), OTf− (3), PF6− (4), SCN−(5)}, [Ag3(dcmp)2][ClO4]3 (6), and [Ag3(dcmp)2Cl2][ClO4] (7) were prepared and their structures were determined by X‐ray crystallography. Complexes 2–4 display a high‐energy emission band with λmax at 442–452 nm, whereas 1 and 5 display a low‐energy emission with λmax at 558–634 nm in both solid state and in dichloromethane at 298 K. The former is assigned to the 3[5dσ*6pσ] excited state of [Au3(dcmp)2]3+, whereas the latter is attributed to an exciplex formed between the 3[5dσ*6pσ] excited state of [Au3(dcmp)2]3+ and the counterions. In solid state, complex [Ag3(dcmp)2][ClO4]3 (6) displays an intense emission band at 375 nm with a Stokes shift of ≈7200 cm−1 from the 1[4dσ*→5pσ] absorption band at 295 nm. The 375 nm emission band is assigned to the emission directly from the 3[4dσ*5pσ] excited state of 6. Density functional theory (DFT) calculations revealed that the absorption and emission energies are inversely proportional to the number of metal ions (n) in polynuclear AuI and AgI linear chain complexes without close metal⋅⋅⋅anion contacts. The emission energies are extrapolated to be 715 and 446 nm for the infinite linear AuI and AgI chains, respectively, at metal⋅⋅⋅metal distances of about 2.93–3.02 Å. A QM/MM calculation on the model [Au3(dcmp)2Cl2]+ system, with Au⋅⋅⋅Cl contacts of 2.90–3.10 Å, gave optimized Au⋅⋅⋅Au distances of 2.99–3.11 Å in its lowest triplet excited state and the emission energies were calculated to be at approximately 600–690 nm, which are assigned to a three‐coordinate AuI site with its spectroscopic properties affected by AuI⋅⋅⋅AuI interactions.
Concentration of aqueous dye solution by freezing and thawing
Authors: Nakagawa Kyuya , Maebashi Shohei , Maeda Koji 
Published: September 2009

AbstractThe concentration phenomena during freezing and thawing were investigated to study the feasibility of freeze–thaw process as a concentration operation. An aqueous dye solution was employed as a model binary eutectic solution. The localised concentration in the frozen matrix was determined, and the concentration profile of the melting solution during thawing was examined. It was found that the solution obtained during thawing showed higher concentration than the original solution, and the concentration did not correspond to the amount of solute localised in the frozen matrix. It was suggested that the concentration phenomena during thawing would be governed by the melting droplet growth rate at the melting interface and by the diffusion rate of solute from eutectic phases to the droplet.
Seismic moment release before the May 12, 2008, Wenchuan earthquake in Sichuan of southwest China
Authors: Jiang Changsheng , Wu Zhongliang 
Published: September 2009

AbstractWhether seismic moment release before great earthquakes exhibits accelerating or quiescence behavior is one of the controversial topics in the study of intermediate‐term earthquake forecast or time‐dependent seismic hazard. The May 12, 2008, Wenchuan earthquake provides a unique opportunity to check whether accelerating moment release (AMR) or quiescence existed before this great earthquake. To systematically analyze the precursory moment release, considering the special characteristics of this great inland thrust event, we took four upgraded approaches using the local earthquake catalogue with cutoff magnitudeML3.0. We propose a BIC criterion as a development of the curvature parameterqto identify the statistically significant acceleration or quiescence behavior as compared with linear increase. We use an ‘eclipse method’ as a development of the ‘interfering event consideration’ to eliminate the interference from the nearby seismically active fault zones. We consider the distribution ofm‐coefficient in the (T,R,Mc) space, to explore the variation of moment release behavior with temporal window lengthTand spatial window radiusRcentered at the nucleation point, and cutoff magnitudeMcof the catalogue in use. We use not only circular windows but also ‘crack‐like’ windows to investigate the overall behavior of the moment release associated with the Wenchuan earthquake. Through this retrospective case study, it is observed that moment release before the Wenchuan earthquake did show accelerating moment release (AMR) and quiescence behavior for different spatio‐temporal ranges, with robustness to some extent against the changing of parameters, indicating the preparation process of this great earthquake. However, for this earthquake, to constrain the failure time in a forward forecasting mode is shown to be difficult. Copyright © 2009 John Wiley & Sons, Ltd.
Enhancing Electron Collection Efficiency and Effective Diffusion Length in Dye‐Sensitized Solar Cells
Authors: Wong Daniel Kwan‐Pang , Ku Chen‐Hao , Chen Yen‐Ru , Chen Guan‐Ren , Wu Jih‐Jen 
Published: September 2009

AbstractIntensity‐modulated photocurrent spectroscopy and intensity‐modulated photovoltage spectroscopy are employed to measure the dynamics of electron transport and recombination in the ZnO nanowire (NW) array‐ZnO/layered basic zinc acetate (LBZA) nanoparticle (NP) composite dye‐sensitized solar cells (DSSCs). The roles of the vertical ZnO NWs and insulating LBZA in the electron collection and transport in DSSCs are investigated by comparing the results to those in the TiO2–NP, horizontal TiO2–NW and vertical ZnO–NW‐array DSSCs. The electron transport rate and electron lifetime in the ZnO NW/NP composite DSSC are superior to those in the conventional TiO2–NP cell due to the existence of the vertical ZnO NWs and insulating LBZA. It indicates that the ZnO NW/NP composite anode is able to sustain efficient electron collection over much greater thickness than the TiO2–NP cell does. Consequently, a larger effective electron diffusion length is available in the ZnO composite DSSC.
An optical microscopy study of the biaxial ‐ calamitic nematic lyotropic phase transition
Authors: Oliveira D. A. , Luders D. D. , Souza G. P. , Kimura N. M. , Palangana A. J. 
Published: September 2009

AbstractLyotropic nematic textures are investigated, using optical microscopy, near the reentrant isotropic (IRE) ‐ discotic nematic (ND‐) ‐ biaxial nematic (NB) ‐ calamitic nematic (NC+) ‐ isotropic (I) phase transitions in a lyotropic mixture of potassium laurate, decanol and D2O. The NB, intermediate phase between the two uniaxial nematic ones, is characterized by optical birefringence measurements. In this way, using a polarizing microscope and a colour CCD digital camera, the NB – NC+ phase transition is identified as well as the domain of the NB phase and ND‐ – NB transition point in accordance with optical birefringence data (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)