bluuebunny/crossref_metadata_2025 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

BACKGROUND:

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

The 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

Understanding 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

Lignocellulosic 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

Cell‐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

The 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

Overall 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

Three 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

Electroenzymatic 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

The 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

Self‐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

The 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

The 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

Whether 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

Intensity‐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

Lyotropic 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)
Solutocapillary convection in germanium‐silicon melts
Authors: Cröll A. , Mitric A. , Aniol O. , Schütt S. , Simon P.
Published: September 2009

Surface tension gradients in free crystal growth melts give rise to convective flow. If these gradients are due to thermal gradients, the well known thermocapillary (Marangoni) convection ensues. Concentration gradients due to segregation at the interface during growth can lead to additional solutocapillary convection. A system with large solutocapillary convection is Ge‐Si due to the pronounced segregation and the strong difference in surface tension; solutal buoyancy convection is also present due to the large density difference between Ge and Si. Solutocapillary convection will oppose thermocapillary convection in the Ge‐Si system since Si, having the higher surface tension, is preferentially incorporated into the crystal. A set of experiments directly proving and partially quantifying the effect has been conducted under microgravity during a parabolic flight campaign by recrystallizing Ge‐Si mixtures of different compositions, between 3% and 9% Si, in a crucible with tracers to visualize the movement. Solutocapillary flow with initial flow rates in excess of 5.5 cm/s at the onset of crystallization was measured. A slight dependence of the flow velocity on the initial Si content has been found. Experiments on the ground showed the same effect but with overall smaller speeds; this difference can be explained by the additional action of solutal buoyancy convection. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
TEM investigation of precipitates in VCz GaAs crystals
Authors: Kirmse H. , Kiessling F.‐M. , Häusler I. , Rudolph P.
Published: September 2009

Bulk GaAs crystals were grown from various Ga‐rich melts by the vapour‐pressure controlled Czochralski method in order to reduce As precipitates. The correlation of the melt composition with both, structural perfection and solid composition was examined by various methods of transmission electron microscopy (TEM). From transmission electron diffraction and diffraction contrast imaging a direct correlation between melt composition and sample properties is missing. High‐resolution TEM imaging hints to inhomogeneities only for the sample grown from a melt with a mole fraction of y = 0.492. Strain analysis of a selected defect reveals a strained crystal lattice in the surrounding of the defect. For the same sample, high angle annular dark‐field imaging and energy dispersive X‐ray spectroscopy verify the formation of precipitates. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth of hierarchical calcium carbonate crystals templated by biomolecules of lotus root
Authors: Chen Long , Hu Fengkai , Zhou Quan , Sun Jinyu , Zhang Hui
Published: September 2009

In this paper, crystal growth of calcium carbonate (CaCO3) in the presence of biomolecules of lotus root was investigated. Scanning electron microscopy, Fourier transform infrared spectroscopy and X‐ray powder diffractometry were used to characterize the products. The results indicate that calcite spherical particles were constructed from small rhombohedral subunits. Similar CaCO3 crystals were also gained when crystal growth of CaCO3 in aqueous solution containing extracts of lotus root was performed, suggesting that the soluble biomolecules of lotus root play a crucial role in directing the formation of hierarchical calcite spherical particles. The possible formation mechanism of the CaCO3 crystals by using lotus root is also discussed, which can be interpreted by particle‐aggregation based non‐classical crystallization laws. The biomolecules of lotus root might induce and control the nucleation and growth of calcium carbonate crystals. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Deposition of CdTe films under microgravity: Foton M3 mission
Authors: Fiederle M. , Benz K. W. , Cröll A. , Zappettini A. , Calestani D. , Dieguez E. , Carotenuto L. , Bassano E.
Published: September 2009

Experiments of deposition of CdTe films have been carried out under microgravity in the Russian Foton M3 mission. The influence of gravity has been studied with these experiments and compared to the results of simulations. The measured deposition rate could be confirmed by the theoretical results for lower temperatures. For higher temperatures the measured thickness of the deposited films was larger compared to the theoretical data. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On driving non‐passive macromodels to instability
Authors: Grivet‐Talocia S.
Published: September 2009

This paper illustrates a procedure for demonstrating and quantifying the importance of passivity in linear macromodels. This issue is critical whenever the macromodels are derived from tabulated port responses, either in time or frequency domain. We show an algorithmic procedure for the design of a passive termination network that will drive a given non‐passive macromodel to instability. Several termination structures characterized by various port couplings are investigated. Relaxed passivity conditions are also given, which guarantee the stability of the macromodel under specific reduced‐coupling loading conditions. Theoretical results are applied to a set of application test cases. Copyright © 2008 John Wiley & Sons, Ltd.
Utility of lyophilized PMA and ionomycin to stimulate lymphocytes in whole blood for immunological assays
Authors: Belouski Shelley Sims , Wilkinson Julie , Thomas John , Kelley Keith , Wang Shen‐Wu , Suggs Sid , Ferbas John
Published: September 2009

Background:

The need to implement robust biomarkers in clinical trials has never been greater, and such efforts can be easily compromised by reagent instability or simple human error during assay set‐up. Many biotechnology and pharmaceutical companies are introducing efforts to conduct biomarker studies under more rigorous settings, and the use of plates or tubes pre‐loaded with stimulation or staining reagents could be of value for studies that involve flow cytometry.

Methods:

Five reagents lyophilized from ethanol or CHAPS buffer stock solution of phorbol 12‐myristate 13‐acetate (PMA) and ionomycin were benchmarked against standard DMSO liquid formulation for their stimulation equivalency. The median fluorescence intensity of phosphorylated ribosomal protein S6 in lymphocytes was assessed on a BD FACSCalibur™.

Results:

We demonstrate here that tubes pre‐loaded with lyophilized versions of the liquid reagents can provide equivalent stimulation in healthy volunteer specimens.

Conclusions:

The value of this approach is that it safeguards against omission or erroneous addition of bulk liquid formulations of PMA and ionomycin to the reaction vessel (i.e., plate or tube) and also lends itself to extended stability/shelf‐life of these reagents. On the basis of this initial success, we plan to expand our evaluation of lyophilized reagents so that they can be incorporated into our clinical biomarker campaigns as appropriate. © 2009 Clinical Cytometry Society
Altered hypoxia‐inducible factor‐1 alpha expression levels correlate with coronary vessel anomalies
Authors: Wikenheiser Jamie , Wolfram Julie A. , Gargesha Madhusudhana , Yang Ke , Karunamuni Ganga , Wilson David L. , Semenza Gregg L. , Agani Faton , Fisher Steven A. , Ward Nicole , Watanabe Michiko
Published: September 2009

The outflow tract myocardium and other regions corresponding to the location of the major coronary vessels of the developing chicken heart, display a high level of hypoxia as assessed by the hypoxia indicator EF5. The EF5‐positive tissues were also specifically positive for nuclear‐localized hypoxia inducible factor‐1 alpha (HIF‐1α), the oxygen‐sensitive component of the hypoxia inducible factor‐1 (HIF‐1) heterodimer. This led to our hypothesis that there is a “template” of hypoxic tissue that determines the stereotyped pattern of the major coronary vessels. In this study, we disturbed this template by altering ambient oxygen levels (hypoxia 15%; hyperoxia 75–40%) during the early phases of avian coronary vessel development, in order to alter tissue hypoxia, HIF‐1α protein expression, and its downstream target genes without high mortality. We also altered HIF‐1α gene expression in the embryonic outflow tract cardiomyocytes by injecting an adenovirus containing a constitutively active form of HIF‐1α (AdCA5). We assayed for coronary anomalies using anti‐alpha‐smooth muscle actin immunohistology. When incubated under abnormal oxygen levels or injected with a low titer of the AdCA5, coronary arteries displayed deviations from their normal proximal connections to the aorta. These deviations were similar to known clinical anomalies of coronary arteries. These findings indicated that developing coronary vessels may be subject to a level of regulation that is dependent on differential oxygen levels within cardiac tissues and subsequent HIF‐1 regulation of gene expression. Developmental Dynamics 238:2688–2700, 2009. © 2009 Wiley‐Liss, Inc.
Prx1 and Prx2 cooperatively regulate the morphogenesis of the medial region of the mandibular process
Authors: Balic Anamaria , Adams Douglas , Mina Mina
Published: September 2009

Mice lacking both Prx1 and Prx2 display severe abnormalities in the mandible. Our analysis showed that complete loss of Prx gene products leads to growth abnormalities in the mandibular processes evident as early as embryonic day (E) 10.5 associated with changes in the survival of the mesenchyme in the medial region. Changes in the gene expression in the medial and lateral regions were related to gradual loss of a subpopulation of mesenchyme in the medial region expressing eHand. Our analysis also showed that Prx gene products are required for the initiation and maintenance of chondrogenesis and terminal differentiation of the chondrocytes in the caudal and rostral ends of Meckel's cartilage. The fusion of the mandibular processes in the Prx1/Prx2 double mutants is caused by accelerated ossification. These observations together show that, during mandibular morphogenesis, Prx gene products play multiple roles including the cell survival, the region‐specific terminal differentiation of Meckelian chondrocytes and osteogenesis. Developmental Dynamics 238: 2599–2613, 2009. © 2009 Wiley‐Liss, Inc.
Syntheses, Crystal Structures, Spectroscopic Properties, and Catalytic Aerobic Oxidations of Novel Trinuclear Non‐Heme Iron Complexes
Authors: Rabe Volker , Frey Wolfgang , Baro Angelika , Laschat Sabine , Bauer Matthias , Bertagnolli Helmut , Rajagopalan Subramanian , Asthalter Tanja , Roduner Emil , Dilger Herbert , Glaser Thorsten , Schnieders David
Published: September 2009

A series of 2,6‐diacylpyridine ligand precursors 5a–d·HCl with different tether lengths between the carboxyl and pyridine moiety was prepared and converted into the correspondig trinuclear Fe3(μ3‐O) complexes 8a–d and 10. Under slow precipitation conditions a tetranuclear complex 9 was isolated instead of 8a. Single‐crystal X‐ray diffraction analyses were performed on ligands 5a–d and complexes 9 and 10. Characterization by X‐ray absorption spectroscopy (XAS) proved a trinuclear Fe3(μ3‐O) core for complexes 8a–d. When complex 8a was submitted to Gif‐type oxidations (O2, Zn, pyridine, HOAc), Mössbauer and nuclear inelastic scattering (NIS) suggested the formation of mononuclear species. The trinuclear ferric complex 10 has an isosceles molecular structure, which is manifested in the 57Fe Mössbauer spectrum by two quadrupole doublets with a 2:1 intensity ratio. The magnetic measurements reveal two moderate antiferromagnetic exchange interactions of –22.1 and –33.8 cm–1. Spin concentrations of complex 10 were determined by EPR spectroscopy, which supports the Mössbauer and magnetic studies. Complexes 8–10 were employed in catalytic aerobic oxidations of adamantane 11, cyclohexene 19, and α‐pinene 23. For adamantane 11, the oxidation of secondary C–H bonds to the corresponding ketone 14 is favored. In addition, adamantylpyridines 15–18 were isolated, thus supporting a radical pathway. A strong preference of allylic oxidation versus epoxidation was found for cyclohexene 19 and α‐pinene 23. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Metalloamphiphiles with [Cu2] and [Cu4] Headgroups: Syntheses, Structures, Langmuir Films, and Effect of Subphase Changes
Authors: Hindo Sarmad Sahiel , Shakya Rajendra , Shanmugam Rama , Heeg Mary Jane , Verani Cláudio N.
Published: September 2009

The metalloamphiphiles [(LPM18)2Cu2Cl2]·H2O (1), [(LPMtax)2Cu2Cl2]·2MeOH (2), [(LOF18)2Cu2Cl2] (3), [(LOF18)2Cu4(μ4‐O)(μ2‐OAc)4] (4), [(LOF14)2Cu4(μ4‐O)(μ2‐OAc)4] (5) were synthesized and characterized by means of several spectroscopic and spectrometric methods. The acronyms LPMC18, LPMtax, LOF18, and LOF14 indicate the deprotonated forms of pseudomacrocyclic (PM) and open‐frame (OF) ligands based on 2,6‐bis(iminomethyl)‐4‐methylphenol attached to octadecyl (18), trialkoxyamine (tax) and tetradecyl (14) moieties, whereas Cl– and OAc– indicate chlorido and acetato coligands. Crystal structures were obtained for 4 and 5 that crystallize in triclinic crystal systems with P$\bar {1}$ space groups. The average Cu–Ophenolate and Cu–Nimine bond lengths are approximately 2.0 Å. Species 1–5 were analyzed by means of isothermal compression and Brewster angle microscopy (BAM). Moderate collapse pressures of approximately 15 mN m–1 were observed for 3, 4, and 5, while 1 collapses at approximately 30 mN m–1. Species 1, 3, 4, and 5 are responsive to several subphase changes such as temperature and addition of terephthalate ions, which leads to considerable Langmuir film enhancement. In presence of terephthalate the collapse pressure for 3, 4, and 5 nearly doubles, whereas a minimal effect was observed for 1. It appears that as temperature decreases, collapse pressure increases. The variation of pH produced inconclusive data. It is suggested that terephthalate ion interacts with the amphiphiles at a molecular level to generate discrete molecules rather than extended systems.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Six‐Membered N‐Heterocyclic Carbenes with a 1,1′‐Ferrocenediyl Backbone: Bulky Ligands with Strong Electron‐Donor Capacity and Unusual Non‐Innocent Character
Authors: Siemeling Ulrich , Färber Christian , Leibold Michael , Bruhn Clemens , Mücke Philipp , Winter Rainer F. , Sarkar Biprajit , von Hopffgarten Moritz , Frenking Gernot
Published: September 2009

The stable, crystalline N‐heterocyclic diaminocarbene fc[N(CH2tBu)‐C‐N(CH2tBu)] (2d, fc = 1,1′‐ferrocenediyl) was prepared by deprotonation of its formamidinium precursor fc[N(CH2tBu)‐CH‐N(CH2tBu)][BF4] (1d) and used for the preparation of the 16 valence electron complexes [Mo(2d)(CO)4], [RhCl(2d)(cod)] (cod = 1,5‐cyclooctadiene) and [RhCl(2d)(CO)2]. 1d, 2d and [RhCl(2d)(cod)] were structurally characterised by single‐crystal X‐ray diffraction studies. The electrochemical properties of 2d, its 2‐adamantyl analogue 2c, its complex [RhCl(2d)(CO)2] and of the precursors 1d and 1,1′‐bis(neopentylamino)ferrocene were investigated by electrochemistry. The carbenes are easily oxidised to the corresponding radical cation, whose persistent nature is unprecedented in the chemistry of N‐heterocyclic carbenes. The spin density is located at the Fe atom and the carbene C atom according to the results of EPR spectroscopic studies and DFT calculations.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Star‐Shaped D‐π‐A Molecules Containing a 2,4,6‐Tri(thiophen‐2‐yl)‐1,3,5‐triazine Unit: Synthesis and Two‐Photon Absorption Properties
Authors: Zou Li , Liu Zijun , Yan Xiaobing , Liu Yan , Fu Yang , Liu Jun , Huang Zhenli , Chen Xingguo , Qin Jingui
Published: September 2009

A series of new star‐shaped donor‐π‐acceptor (D‐π‐A) molecules containing the 2,4,6‐tri(thiophen‐2‐yl)‐1,3,5‐triazine unit were synthesized and characterized. The 1,3,5‐triazine group, as a strong electron‐accepting center, is connected to three electron‐donating end groups through π‐conjugated bridges. As a result of the coexistence of the electron acceptor and donor, these compounds show reversible or quasireversible redox behavior. Through changing the peripheral end group the optical properties can be modified. All compounds exhibit two‐photon absorption activity in the range of 720–880 nm and show large two‐photon absorption cross sections that are closely related to the intramolecular charge transfer and π‐conjugated length of the molecule.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Electrochemical Study of Phenolic Compounds as Enhancers in Laccase‐Catalyzed Oxidative Reactions
Authors: Díaz González María , Vidal Teresa , Tzanov Tzanko
Published: September 2009

Sixteen phenolic compounds, twelve of which derived from lignin, were evaluated as potential mediators for laccase‐assisted bleaching of pulp. The electrochemical behavior of these phenols, alone and in the presence of the lignin model compound veratryl alcohol, was studied by means of cyclic voltammetry. All phenolic compounds showed catalytic effect on the veratryl alcohol electrochemical oxidation. However, they could not be considered as mediators, since their oxidation products are not stable and regeneration of their reduced forms was not observed. The redox potentials of the phenolic compounds seem to have a negligible effect on their catalytic efficiency, supporting a H‐abstraction oxidation mechanism. This mechanism was also confirmed by electrochemical studies of 2,4,6‐trimethylphenol in acetonitrile and in the presence of benzyl alcohols.
The Use of an Electroactive Marker as a SERS Label in an E‐melting Mutation Discrimination Assay
Authors: Mahajan Sumeet , Richardson James , Gaied Nouha Ben , Zhao Zhengyun , Brown Tom , Bartlett Philip N.
Published: September 2009

In this paper we describe the first example of the use of an electroactive label as a SERS marker for detecting and quantifying target oligonucleotides and distinguishing mutations using a combination of voltammetry and electrochemically induced melting (E‐melting). The experiments were carried out on sphere segment void substrates selected to show strong surface enhancement for SERS at 633 nm. DNA analysis was carried out for CFTR sequences using synthetic 22‐mer oligonucleotides labelled with a modified anthraquinone at the 3′‐end. Discrimination between the wild type, 1653C/T (point mutation) and ΔF508 (triple deletion) is demonstrated.
Electrochemical Monitoring of Singlet Oxygen Production
Authors: Sharp Duncan , Forsythe Stephen , Davis James
Published: September 2009

The exploitation of singlet oxygen generating compounds as a means of targeted therapies drives the need to develop methods for assessing the efficacy of such compounds and their capacity for generating the reactive oxygen species. Degradation of diphenylisobenzofuran by singlet oxygen is widely used as a spectroscopic probe but its application can be problematic. An alternative detection strategy exploiting the electrochemical monitoring of the quencher concentration, by square wave voltammetry, has been shown to provide a more sensitive and flexible option that could be used to address the increasing interest in photosensitizing materials.
Ion Transfer Square Wave Voltammetry of Ionic Liquid Cations with a Solvent Polymeric Membrane Ion Sensor
Authors: Ortuño Joaquín A. , Serna Carmen , Molina Angela , Torralba Encarnación
Published: September 2009

Square wave voltammetry (SWV) with a solvent polymeric membrane ion sensor has been applied to study the ion transfer of several ionic liquid cations, from water to a poly(vinyl chloride) membrane plasticized with 2‐nitrophenyl octyl ether. The study has mainly been focused on dialkylimidazolium and alkylpyridinium cations. The experimental voltammograms obtained are in good agreement with the theoretical predictions. The standard ion transfer potentials of the ionic liquid cations have been obtained and the values found have been used to draw some conclusions on the relationship between structure and lipophilicity. Also, a relationship between the toxicity and the ion transfer potentials of dialkylimidazolium homologues has been found.
Investigation of deformation and breakup of a moving droplet by the method of lattice Boltzmann equations
Authors: Fakhari A. , Rahimian M. H.
Published: September 2009

The subject of the present study is to investigate the deformation and fragmentation of a moving droplet in a zero gravity uniform gas flow. The lattice Boltzmann method is employed to simulate different modes of deformation and breakup of the drop. Two‐dimensional results are compared with axisymmetric computations and major difference in the mechanisms of breakup and the rate of deformations is shown. Influence of the drop and gas viscosities as well as surface tension effect is investigated for some range of the Reynolds and Weber numbers. It is seen that the increase of the Reynolds or Weber number results in the increase of drop deformation and finally breakup. The quality of the findings is similar to the experimental observations. Different breakup regimes such as bag breakup and shear breakup are observed. The primary breakup time and the cross‐stream radius of the axisymmetric drop before bag breakup are shown to be in satisfactory agreement with experimental data. Copyright © 2009 John Wiley & Sons, Ltd.
Source‐based morphometry of gray matter volume in men with first‐episode schizophrenia
Authors: Kašpárek Tomáš , Mareček Radek , Schwarz Daniel , Přikryl Radovan , Vaníček Jiří , Mikl Michal , Češková Eva
Published: September 2009

Objectives: There is a lot of variability between the results of studies reporting the pattern of gray matter volume changes in schizophrenia. Methodological issues may play an important role in this heterogeneity. The aim of the present study was to replicate the better performance of multivariate “source‐based morphometry” (SBM) over the mass‐univariate approach. Experimental design: Voxel‐based morphometry of Jacobian‐modulated gray matter volume images, using voxel and cluster level inference, and SBM were performed in a group of first‐episode schizophrenia patients (N = 49) and healthy controls (N = 127). Results: Using SBM we were able to find a significant reduction of gray matter volume in fronto‐temporo‐cerebellar areas whereas no significant results were obtained using voxel‐based morphometry. Conclusion: Multivariate analysis of gray matter volume seems to be a suitable method for characterization of the pattern of changes at the beginning of the illness in schizophrenia subjects. Hum Brain Mapp, 2010. © 2009 Wiley‐Liss, Inc.
Environmental influence on L1 retrotransposons in the adult hippocampus
Authors: Muotri Alysson R. , Zhao Chunmei , Marchetto Maria C.N. , Gage Fred H.
Published: September 2009

It is well established that neuronal circuits can be shaped by experience. Neuronal plasticity can be achieved by synaptic competitive interactions and the addition of new neuronal units in neurogenic regions of the adult brain. Recent data have suggested that neuronal progenitor cells can accommodate somatic LINE‐1 (Long Interspersed Nuclear Elements‐1 or L1) retrotransposition. Genomic L1 insertions may up‐ or down‐regulate transcriptional control of gene expression. Here, we show that exercise has a positive effect on a L1‐EGFP reporter in vivo. We found that neurons from mice that experience voluntary exercise are more likely to activate an EGFP reporter marker, representing L1 insertions in the brain, when compared with sedentary animals. In the hippocampus, a neurogenic region of the adult brain, EGFP expression is mainly found in cells localized in the subgranular layer of the dentate gyrus. This observation implies that neuronal progenitor cells may support de novo retrotransposition upon exposure to a new environment. Such evidence suggests that experience‐dependent L1 retrotransposition may contribute to the physiological consequences of neuronal plasticity. © 2009 Wiley‐Liss, Inc.