bluuebunny/crossref_metadata_2025_split huggingface dataset:
Production of Levulinic Acid from Bagasse and Paddy Straw by Liquefaction in the Presence of Hydrochloride Acid
Authors: Yan Lifeng , Yang Naikun , Pang Hao , Liao Bing 
Published: February 2008

AbstractA method of levulinic acid production from bagasse and paddy straw is presented. Biomass waste was mixed with hydrochloride acid and water, and then liquefied at about 200°C in a pressurized reactor. Both the mass of the biomass and the amount of hydrochloride acid were kept as constants, and the effects of temperature, reaction time, and acid concentration on the levulinic acid yield were studied. It was found that the yield of levulinic acid was maximum when the reaction temperature was carried out for 45 min at 220°C using 4.45% concentration of hydrochloride acid, and the maximum yields of levulinic acid were 22.8 and 23.7% for bagasse and paddy straw, respectively. The products were analyzed using NMR, HPLC, and GC/MS.
Spatial patterning of cholinergic amacrine cells in the mouse retina
Authors: Whitney Irene E. , Keeley Patrick W. , Raven Mary A. , Reese Benjamin E. 
Published: February 2008

AbstractThe two populations of cholinergic amacrine cells in the inner nuclear layer (INL) and the ganglion cell layer (GCL) differ in their spatial organization in the mouse retina, but the basis for this difference is not understood. The present investigation examined this issue in six strains of mice that differ in their number of cholinergic cells, addressing how the regularity, packing, and spacing of these cells varies as a function of strain, layer, and density. The number of cholinergic cells was lower in the GCL than in the INL in all six strains. The nearest neighbor and Voronoi domain regularity indexes as well as the packing factor were each consistently lower for the GCL. While these regularity indexes and the packing factor were largely stable across variation in density, the effective radius was inversely related to density for both the GCL and INL, being smaller and more variable in the GCL. Consequently, despite the lower densities in the GCL, neighboring cells were more likely to be positioned closer to one another than in the higher‐density INL, thereby reducing regularity and packing. This difference in the spatial organization of cholinergic cells may be due to the cells in the GCL having been passively displaced by fascicles of optic axons and an expanding retinal vasculature during development. In support of this interpretation, we show such displacement of cholinergic somata relative to their dendritic stalks and a decline in packing efficiency and regularity during postnatal development that is more severe for the GCL. J. Comp. Neurol. 508:1–12, 2008. © 2008 Wiley‐Liss, Inc.
Spin‐Resolved Rotational Energy Transfer for the CH B 2Σ−(v=0, N, F) State by Collisions with Ar
Authors: Tsai Ming‐Tsang , Tsai Po‐Yu , Alexander Millard H. , Lin King‐Chuen 
Published: February 2008

AbstractAn experimental and theoretical investigation of rotational energy transfers (RET) of CH involving the B 2Σ− (v=0, 0≤N≤5, F) state by collisions with Ar is undertaken, using the photolysis‐probe technique. Time‐resolved laser‐induced fluorescence resulting from an initially prepared fine‐structure label is dispersed using a step‐scan Fourier transform spectrometer. The spin‐resolved RET rate constants are evaluated with the simulation of a kinetic model. The quantum‐scattering method is used for the calculation of the fine‐structure‐resolved cross sections and rate constants in the rotationally inelastic collisions. The theoretical values are generally consistent with our experimental findings, both in the order of magnitude and trend of N and ΔN dependence. The propensity rules obtained from the experiments are essentially obeyed by theoretical calculations, and are also in accordance with those reported by Kind and Stuhl. The RET rate constants obtained for the v=0 level are smaller than those obtained previously for v=1. The discrepancy in the RET behavior may be caused by an anisotropy difference of the interaction potential resulting from vibrational excitation.
Characterization of SiO2 Deposited by CVD on MoxOy/Al2O3 using NMR and TOF‐SIMS
Authors: Boateng K. A. , Hill J. M. 
Published: February 2008

AbstractSilica (SiO2) is deposited onto the surface of MoxOy/Al2O3 using CVD in a fluidized bed. The resulting deposit is characterized using N2 physisorption, inductively coupled plasma (ICP) spectrometry, 29Si nuclear magnetic resonance (NMR) and time of flight‐secondary ion mass spectrometry (TOF‐SIMS). The ICP and physisorption results show that the amount deposited on the surface reaches a plateau value after 30‐60 min. Based on the NMR and TOF‐SIMS analysis, this plateau value corresponds to 2‐3 monolayers. The surface coverage is not uniform, and the presence of Mo on the exterior surface of Al2O3 hinders the deposition of silica.
The Influence of In/Cu Ratio on Electrical Properties of CuO:In Thin Films Prepared by Plasma‐Enhanced CVD
Authors: Hao Y. , Gong H. 
Published: February 2008

AbstractCuO:In thin films were prepared by plasma‐enhanced chemical vapor deposition (CVD) with Cu(acac)2 and In(acac)3 precursors. A unique method or facility in vaporizing solid‐state precursors and the transportation to the CVD reactor was described. The structure of the films evolved from nano‐crystalline characteristic to amorphous state as the In/Cu atomic ratio of the mixed precursors increased from 0 to 0.25. A dependence of the resistivity of the films on the indium concentration was found. A low room‐temperature resistivity of 7.35 Ω·cm was achieved for the sample of an In/Cu atomic ratio of 0.08, with an activation energy of 0.14 eV. X‐ray photoelectron spectroscopy (XPS) study excluded the possibility that the increased conductivity of the samples came from a reduction of Cu2+ to Cu+. Positive holes (h•) induced by negatively charged defect complex $ ({In}^{\bullet} _{Cu} + V^{\Prime} _{Cu}) $ were assumed to contribute to the increase of conductivity.
Formation of the Porous Structure of Silicon Dioxide Thin Layers During Silane Oxidation
Authors: Dultsev F. N. 
Published: February 2008

AbstractModeling of silicon dioxide deposition is carried out at the level of elementary chemical gas‐phase stages for low pressure and plasma enhanced CVD processes. It is shown on the basis of modeling results compared with the previously reported experimental data that the formation of porous structure of silicon dioxide films deposited by means of silane oxidation is governed by gas‐phase intermediates and products (especially water) formed during oxidation. Modeling results allowed us to explain the role of different additives (e.g. ammonia, propylene) that were observed to affect the porous structure of films: ammonia causes a decrease in total film porosity, while propylene allows one to obtain the films with high porosity and uniform pore size. Thus the chemical nature of the effect of gas‐phase elementary stages of the process on the characteristics of the resulting solid silicon dioxide film is revealed.
Bioinspired Energy Conversion Systems for Hydrogen Production and Storage
Authors: Fukuzumi Shunichi 
Published: February 2008

AbstractRecent developments in photocatalytic hydrogen production by using artificial photosynthesis systems is described, together with those in hydrogen storage through the fixation of CO2 with H2. Hydrogen can be stored in the form of formic acid, which can be converted back to H2 in the presence of an appropriate catalyst. Electron donor–acceptor dyads are utilized as efficient photocatalysts to reduce methyl viologen (MV2+) by NADH (β‐nicotinamide adenine dinucleotide, reduced form) analogues to produce the methyl violgen radical cation that acts as an electron mediator for the production of hydrogen. Porphyrin‐monolayer‐protected gold clusters that enhance the light harvesting efficiency can also be used for the photocatalytic reduction of methyl viologen by NADH analogues. The use of a simple electron donor–acceptor dyad, the 9‐mesityl‐10‐methylacridinium ion (Acr+–Mes), enables the construction of a highly efficient photocatalytic hydrogen‐evolution system without an electron mediator such as MV2+, with poly(N‐vinyl‐2‐pyrrolidone)‐protected platinum nanoclusters (Pt–PVP) and NADH as a hydrogen‐evolution catalyst and an electron donor, respectively. Hydrogen thus produced can be stored in the form of formic acid (liquid) by fixation of CO2 with H2 in water by using ruthenium aqua complexes [RuII(η6‐C6Me6)(L)(OH2)]2+ [L = 2,2′‐bipyridine (bpy), 4,4′‐dimethoxy‐2,2′‐bipyridine (4,4′‐OMe‐bpy)] and iridium aqua complexes [IrIIICp*(L)(OH2)]2+ (Cp* = η5‐C5Me5, L = bpy, 4,4′‐OMe‐bpy) as catalysts at pH 3.0. Catalytic systems for the decomposition of HCOOH to H2 are also described. The combination of photocatalytic hydrogen generation with the catalytic fixation of CO2 with H2 and the decomposition of HCOOH back to H2 provides an excellent system for cutting CO2 emission.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Estimation of stereospecific fatty acid distribution in vegetable oils from liquid chromatography data
Authors: Sovová Helena , Lísa Miroslav , Holčapek Michal 
Published: February 2008

AbstractThe fatty acid distribution in triacylglycerols (TG), the major components of vegetable oils, affects the physical properties of oils and their physiological effects as components of the human diet. A computational scheme is proposed for estimating the stereospecific distribution of fatty acids in TG on the basis of the data from HPLC analysis, using a model for TG synthesis. A new model for the synthesis is proposed which, in contrast to the widely used model published independently by Vander Wal and Coleman, enables us to simulate the asymmetrical fatty acid distribution at the sn‐1 and sn‐3 stereochemical positions. The computational scheme combined with either literature models or the new model was validated by its application to several TG profiles and comparison of the resulting fatty acid distribution at stereochemical positions with experimental data from the literature. The stereospecific composition of TG was calculated using the new model for nine vegetable oils.
Total Synthesis and Biological Activity of (±)‐Rocaglamide and Its 2,3‐Di‐epi Analogue
Authors: Li Hongsen , Fu B. , Wang M. A. , Li N. , Liu W. J. , Xie Z. Q. , Ma Y. Q. , Qin Zhaohai 
Published: February 2008

AbstractBy introducing the strategy of intramolecular reductive coupling to construct the cyclopenta[b]benzofuran skeleton, the shortest and most efficient synthetic method hitherto was now established to rocaglamide 1 and its 2,3‐di‐epi analogue 3 in racemic form by Michael addition, SmI2‐promoted intramolecular keto–ester coupling, amination of the ester intermediate, and reduction of carbonyl with Me4NBH(OAc)3. Several steps were highly stereoselective or even stereospecific. The bioassay results indicated that both 1 and 3 were much better repellents against Plutella xylostella than azadirachtin; the insecticidal activity of 1 was higher than that of azadirachtin against Pieris rapae, P. xylostella, Laphygma exigua, and Helicoverpa armigera, but that of 3 was lower.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Microwave‐Induced Synthesis and Regio‐ and Stereoselective Epoxidation of 3‐Styrylchromones
Authors: Patonay Tamás , Kiss‐Szikszai Attila , Silva Vera M. L. , Silva Artur M. S. , Pinto Diana C. G. A. , Cavaleiro José A. S. , Jekő József 
Published: February 2008

AbstractThe microwave‐assisted solvent‐free synthesis of (E)‐3‐styrylchromones from 3‐formylchromones and phenylmalonic acid on sodium acetate support has been developed; the method affords the styryl derivatives in moderate to good yields and with complete diastereoselectivity. Protocols for the highly regioselective epoxidation of (E)‐ and (Z)‐3‐styrylchromones have been elaborated. Treatment of the alkenes with dimethyldioxirane led to the exclusive formation of 3‐(3‐aryloxiran‐2‐yl)chromones with complete diastereoselectivity, whereas treatment with hydrogen peroxide under alkaline conditions afforded the corresponding 2,3‐epoxy‐3‐styrylchromanones as the only products. Epoxidation performed in the presence of chiral, nonracemic cinchona‐alkaloid‐based quaternary ammonium salts allowed the synthesis of enantiomerically enriched 2,3‐epoxy‐3‐styrylchromanones, but with only moderate ee values. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Thermal Effects in the Organocatalytic Asymmetric α‐Amination of Disubstituted Aldehydes with Azodicarboxylates: A High‐Temperature Organocatalysis
Authors: Baumann Thomas , Bächle Michael , Hartmann Caroline , Bräse Stefan 
Published: February 2008

AbstractThis article describes the thermally accelerated organocatalytic α‐amination of disubstituted aldehydes with azodicarboxylates under microwave conditions. Compared to the results previously obtained at room temperature, both yield and enantioselectivity could be significantly increased. Employing microwave irradiation resulted in a considerably reduced reaction time. Therefore, this improved protocol allows the fast and efficient synthesis of α,α‐disubstituted amino aldehydes and provided the best results for the α‐amination of disubstituted aldehydes to date. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
A Simple and Inexpensive Method for Fabrication of Ultramicroelectrode Array and Its Application for the Detection of Dissolved Oxygen
Authors: Xu Xiaolong , Liu Changyu , Jia Jianbo , Liu Baifeng , Yang Xiurong , Dong Shaojun 
Published: February 2008

AbstractHerein, we report a simple and inexpensive way for fabrication of ultramicroelectrode arrays (UMEAs) and the relative characterization methods. The fabrication of UMEAs involves only a few steps of handwork. Since only metal wires and epoxy are used through the fabrication process, it is supposed to be a quite straightforward method for preparing UMEAs. A dissolved oxygen (DO) sensor based on UMEAs was constructed. The detection of DO in different aqueous samples is fast, reliable and reproducible. The surface of UMEAs fabricated can be renewed simply by mechanically polishing or electrochemical treatment, which is of great advantage to practical applications.
Supramolecular Assembly of β‐Cyclodextrin‐Capped Gold Nanoparticles on Ferrocene‐Functionalized ITO Surface for Enhanced Voltammetric Analysis of Ascorbic Acid
Authors: Zuo Fang , Luo Chunhua , Zheng Zhaohui , Ding Xiaobin , Peng Yuxing 
Published: February 2008

AbstractA supramolecular recognition functionalized electrode (βCD‐nanoAu/Fc‐ITO) which exhibits redox‐activity was prepared through supramolecular assembly of β‐cyclodextrin (βCD) capped gold nanoparticles (βCD‐nanoAu) on the ITO previously coated with a monolayer of ferrocene residues (Fc‐ITO). The immobilization of βCD‐nanoAu on Fc‐ITO was confirmed by atomic force microscopy (AFM), and the supramolecular nature of the immobilization approach was also confirmed by cyclic voltammetry. On the other hand, the electrocatalytic activity of βCD‐nanoAu/Fc‐ITO electrode was also studied. The electrocatalytic activity toward ascorbic acid (AA) was enhanced compared with that at the Fc‐ITO electrode, and a linear relationship existed between the anodic peak and the concentration of AA in the range of 5.3×10−5 to 3.0×10−3 M with a detection limit (S/N=3) of 4.1×10−6 M.
Integrating an Enzyme‐Entrapped Conducting Polymer Electrode and a Prereactor in a Microfluidic System for Sensing Glucose
Authors: Nien Po‐Chin , Huang Meng‐Chi , Chang Fuh‐Yu , Ho Kuo‐Chuan 
Published: February 2008

AbstractIn this study, the flow injection analysis was applied to the enzyme‐entrapped electrode on a chip for sensing glucose. The on‐chip microelectrode was fabricated by the standard photolithography in clean‐room environment and the microfluidic channel height of 100 μm on the chip was formed by poly(dimethylsiloxane). The conducting polymer, poly(3,4‐ethylenedioxythiophene), PEDOT, was electropolymerized to entrap the coexisting glucose oxidase (GOD) by cyclic voltammetry (CV). The amount of enzyme entrapped in the matrix measured spectroscopically was about 0.101 U/cm2. At a flow rate of 10 ml/hr, the working electrode (Pt/PEDOT/GOD, WE1) was set at 0.7 V (vs. Ag/AgCl) and sensing of H2O2 was carried out by injecting samples with various concentrations of glucose (Glu). A linear relationship between the sensing current and the glucose concentration, ranging from 1 to 20 mM, was obtained with a sensitivity of 8 nA mm−2 mM−1. The response time and the recovery time were about 30 and 230 s, respectively. For a single‐potential test, the oxidation currents of 0.08 mM ascorbic acid (AA) and a blend of 0.08 mM AA and 10 mM Glu reached 31.3% and 145.5%, respectively, when compared with the oxidation current of 10 mM Glu alone. However, when a pre‐reactor (WE2) was set at the same potential (0.7 V) before the main enzyme integrated electrode (WE1), the oxidation current for the above mixed solution reached 99.6% of the original one.
Endonucleolytic mutation analysis by internal labeling (EMAIL)
Authors: Cross Michael J. , Waters Daniel L. E. , Lee L. Slade , Henry Robert J. 
Published: February 2008

AbstractMismatch‐specific endonucleases are efficient tools for the targeted scanning of populations for subtle DNA variations. Conventional protocols involve 5′‐labeled amplicon substrates and the detection of digestion products by LIF electrophoresis. A shortcoming of such protocols, however, is the limited 5′‐signal strength. Normally the sensitivity of fluorescent DNA analyzers is superior to that of intercalating dye/agarose systems, however, pooling capacities of the former and latter approaches to mismatch scanning are somewhat similar. Detection is further limited by significant background. We investigated the activity of CEL nucleases using amplicon substrates labeled both internally and at each 5′‐terminus. The amplicons were generated from exon 8 of the rice starch synthase IIa encoding gene. Signal of both 5′‐labels was significantly reduced by enzyme activity, while that of the internal label was largely unaffected. In addition, background resulting from internal labeling was a significant improvement on that associated with 5′‐labeling. Sizing of the multilabeled substrates suggests that 5′‐modification enhances exonucleolytic activity, resulting in the removal of the dye‐labeled terminal nucleotides. We have developed an alternative approach to mismatch detection, in which amplicon labeling is achieved via the incorporation of fluorescently labeled deoxynucleotides, which we have named Endonucleolytic Mutation Analysis by Internal Labeling (EMAIL). The strength of the EMAIL assay was demonstrated by the reclassification of a rice line as being heterozygous for the starch gene. This cultivar was assigned as being homozygous by a previous resequencing study. EMAIL shows potential for the clear identification of multiple mutations amongst allelic pools.
Integrated isotachophoretic stacking and gel electrophoresis on a plastic substrate and variations in detection dynamic range
Authors: Lin Chun‐Che , Hsu Bi‐Kei , Chen Shu‐Hui 
Published: February 2008

AbstractIn this study, we demonstrated an integrated ITP–gel electrophoresis (GE) device on a plastic substrate, in which 50 nL of samples could be hydrodynamically or electrokinetically injected and enriched by ITP into narrow bands and then subsequently introduced into a homogeneous GE channel for separation and detection. This microchip design rendered a simple introduction scheme for creating sandwiched stacking buffer system and flexibilities in choosing separation and stacking buffers independently. We used gel sieving buffers which compositions were different from those for stacking buffers to separate DNA and protein molecules based on sizing mechanism. Compared to conventional microchip GE, the sensitivity of microchip ITP‐GE was estimated to increase by one to two orders of magnitude based on the dilution factor of the injected sample and the S/N ratio detected from the electropherogram. Moreover, it is interesting to note that ITP stacking leads to a preferential enhancement for analytes with lower concentrations compared to those with higher concentrations. Therefore, a reduction in the detection dynamic range for ITP‐GE was gained. We demonstrated that ITP‐GE could lead to 2–4‐folds of reduction in the signal dynamic range for two PCR products in a mixture. Such advantage is demonstrated to be useful for the detection of two products amplified from a multiplex PCR in which one product is poorly amplified compared to the other.
Discovering novel targets for autoantibodies in dilated cardiomyopathy
Authors: Buse Christina , Altmann Frank , Amann Barbara , Hauck Stefanie M. , Poulsen Nautrup Cordula , Ueffing Marius , Stangassinger Manfred , Deeg Cornelia A. 
Published: February 2008

AbstractThere is increasing evidence that a large proportion of dilated cardiomyopathy (DCM) cases are mediated by autoimmune processes. Since DCM is a fatal disorder with rapid aggravation and is the leading cause of heart transplantation, further insights into disease pathogenesis are needed. Recent studies have separated the pathogenic capacity of autoantibodies and initial clinical trials removing such autoantibodies via immunoadsorption have been promising. In order to elucidate the full autoantibody repertoire involved in DCM, we applied an autoantibody screening test using ventricular and atrial proteomes as autoantigenic sources and subsequently tested the autoantibody‐binding patterns of sera from dogs with spontaneous DCM. With this method, we detected five potentially DCM‐related autoantigens which were identified by MS as being: myosin heavy chain cardiac muscle alpha isoform, alpha cardiac actin, mitochondrial aconitate hydratase, glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH), and brain glycogen phosphorylase (GPBB). The recovery of two known DCM autoantigens (myosin heavy chain and alpha cardiac actin) and the discovery of three novel autoantigens (mitochondrial aconitate hydratase, GADPH, and GPBB) underscore the efficacy of this experimental method and the significance of the spontaneous canine DCM model.