bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modified TLC bioautographic method for screening acetylcholinesterase inhibitors from plant extracts
Authors: Yang Zhongduo , Zhang Xu , Duan Dongzhu , Song Zhuwen , Yang Mingjun , Li Shuo 
Published: August 2009

AbstractThe present work describes modifications to an existing TLC bioautographic method for detecting acetylcholinesterase inhibitors from plant extracts. The basic principle of the method is that the enzyme converts 1‐naphthyl acetate into naphthol which reacts with Fast Blue B salt to make a purple‐colored background on the TLC plates. Inhibitors of acetylcholinesterases produced white spots on the background. Our modifications involve changes in the concentration of the enzyme, the reagents, and the time of the reaction. With these changes, the consumption of the enzyme was reduced by 85% and the detection limits were decreased remarkably.
CE‐LIF chiral separation of aspartic acid and glutamic acid enantiomers using human serum albumin and sodium cholate as dual selectors
Authors: Wang Shumin , Fan Li , Cui Shuya 
Published: August 2009

AbstractSodium cholate (SC), β‐CD, hydroxypropyl (HP)‐β‐CD, HSA, and the dual mixtures of them were evaluated for the analysis of aspartic acid (Asp) and glutamic acid (Glu) enantiomers fluorescently tagged with 5‐(4,6‐dichloro‐s‐triazin‐2‐ylamino) fluorescein (DTAF) by CE with LIF detection. Among the investigated chiral selectors and the dual selector systems, the dual selector systems of HSA and SC resulted to be the most useful chiral selectors allowing relatively high chiral resolution. Several experimental parameters such as chiral reagent type and concentration, buffer concentration, and pH, type and concentration of organic modifier were studied in order to find the optimum conditions for the chiral resolution of the two derivatized amino acids in their enantiomers. The effect of different variables that affect derivatization (time, temperature, pH, and DTAF concentration) was studied. Under optimum conditions, the analytes were separated in a short 10.5 min analysis time, and the RSDs for migration time and peak area were less than 0.12 and 2.8%, respectively. The method was applied for the analysis of compound amino acids injection without interference from other amino acids in the sample matrices observed.
Competitional hydrophobicity driven separations under RP‐LC mechanism: Application to sulfonylurea congeners
Authors: David Victor , Galaon Toma , Caiali Edvin , Medvedovici Andrei 
Published: August 2009

AbstractRetention of a model set of sulfonylurea compounds has been studied under RP‐LC conditions, considering competitional effects brought by different alcohols (ethanol, 1‐propanol, 2‐propanol, 1‐butanol, 1‐pentanol, and 1‐octanol) used as additives in the organic component of the mobile phase (methanol). The capacity factors determined for the model compounds decreased with the increase of the hydrophobic character of the organic additive in the mobile phase. The amount of the additive within the organic component of the mobile phase was kept constant (1% as volumetric ratio). Retention was studied at different mobile phase compositions (aqueous to organic component ratios). Different functional fitting models were used to correlate retention to the content of the organic component in the mobile phase. Extrapolation of retention expressed as capacity factor to a mobile phase composition free of organic component is well correlated to the hydrophobic characteristics of the organic additives. The adsorption model was used for tuning the experimental find‐outs. The possibility of controlling retention through the competitive effects induced by hydrophobic additives in the mobile phase is highlighted.
Phospholipase Cζ mRNA expression and its potency during spermatogenesis for activation of quail oocyte as a sperm factor
Authors: Mizushima Shusei , Takagi Soichi , Ono Tamao , Atsumi Yusuke , Tsukada Akira , Saito Noboru , Shimada Kiyoshi 
Published: August 2009

AbstractThis study was conducted to investigate the role of a sperm‐borne compound in oocyte activation in special reference to the time when oocyte activation is required by testicular cells during spermatogenesis in quail. First, effects of a microinjection of quail sperm extract (SE) and quail phospholipase Cζ (PLCζ) cRNA into quail oocytes were assessed by observation of pronuclear formation and cytoplasmic segmentation, respectively. Secondly, the effects of a microinjection of round spermatids with or without PLCζ cRNA into quail oocytes were studied by observation of development. When the oocytes were injected with SE at 0.13 mg protein/ml, both pronuclear formation and cytoplasmic segmentation were optimally induced. However, pronuclear formation was blocked when SE was pretreated with heat or when the oocyte was pretreated with BAPTA (a Ca2+ chelator) before SE injection. On the other hand, when the oocytes were injected with PLCζ cRNA at 60 µg/ml, not only pronuclear formation but also cytoplasmic segmentation were optimally induced. However, PLCζ cRNA‐induced pronuclear formation was blocked by pretreatment with cycloheximide (an inhibitor of protein synthesis) or with BAPTA. Most interestingly, round spermatids alone cannot induce blastodermal development but microinjection of a round spermatid with PLCζ cRNA can induce development. In addition, RT‐PCR revealed that PLCζ mRNA is expressed in elongated spermatids and testicular sperm but not in round spermatids. It is concluded that PLCζ is a functional sperm factor for oocyte activation to initiate resumption of meiotic division in quail and its potency is acquired after elongated spermatid formation during the spermatogenesis. Mol. Reprod. Dev. 76: 1200–1207, 2009. © 2009 Wiley‐Liss, Inc.
A new dynamic one‐equation subgrid‐scale model for large eddy simulations
Authors: Huang Shenghong , Li Q. S. 
Published: August 2009

AbstractA new dynamic one‐equation subgrid‐scale (SGS) model is presented for large eddy simulations of turbulent flows. The new model, combining both advantages of the dynamic one‐equation SGS model (J. Appl. Mech. (ASME) 2006; 73:368–373) and the wall‐adapting local eddy viscosity model (Turbulence Combustion 1999; 62:183–200), has three prominent features: (1) one‐equation model, suitable for relatively coarse grid situations and simulation of high Reynolds number flows; (2) no test‐filtering operation is needed in determination of dynamic parameters, suitable for low‐order numerical discretization and unstructured or hybrid grid situations; and (3) treating the production of SGS kinetic energy and energy loss in grid‐scale (GS) portion due to SGS motion with different dynamic mechanisms, which is considered to be more reasonable than the local and instantaneous dynamic mechanism as adopted by most existing one‐equation dynamic SGS models. Computational examinations have been conducted for flows with Reynolds number ranging from 3000–70000, revealing that there are three promising aspects of the new SGS model: (1) adaptability for a wide range of flow regime; (2) less grid dependence; and (3) potential of wide applications in complex geometries and high Reynolds number turbulent flows. Copyright © 2009 John Wiley & Sons, Ltd.
Form‐anisotropy of 2D nanostructures: Modeling approaches comparison
Authors: Lutich Andrey , Gaponik Nikolai , Eychmüller Alexander , Gaponenko Sergey 
Published: August 2009

AbstractFor the first time different effective medium approximations that are widely used for effective refractive index and form‐anisotropy simulations in 2D nanostructures are compared to the plane‐wave expansion approach from the point of view of the refractive indices and form‐birefringence simulation accuracy. Applicability criteria (porosity and refractive index contrast regions) for the different effective medium models are analyzed on the basis of the comparison to the results obtained by means of the plane‐wave expansion approach. It is shown that simplified approaches at certain structural parameters lead to unacceptable inaccuracy of the form‐birefringence calculations whereas they give reasonably rough estimates of the effective refractive index.
Correlation between thermally and optically stimulated luminescence in beta‐irradiated undoped CVD diamond
Authors: Chernov V. , Piters T. M. , Meléndrez R. , Preciado‐Flores S. , May P. W. , Barboza‐Flores M. 
Published: August 2009

AbstractThe behaviour of afterglow (AG), thermoluminescence (TL) and infrared‐stimulated luminescence (IRSL) in beta‐irradiated chemical vapour deposition diamond is presented. The TL glow curve consists of four peaks with maxima at about 380, 430, 530 and 610 K. The AG decay is fitted by Becquerel's law with exponent close to 1, and correlates well with the thermal emptying of the traps responsible for the 380 K peak. Stimulation with IR light (830 nm) creates intense IRSL and destroys the 380, 430 and 530 K peaks. Illumination with shorter wavelength light also destroys the 610 K peak. The thermal cleaning procedure removes subsequently TL peaks, AG and IRSL. The AG signal decays together with the disappearance of the 380 K peak. The IRSL signal decays continuously with the removal of the 380, 430 and 530 K peaks. Traps responsible for the 610 K peak do not participate in the IRSL process.
Towards optical‐quality nanocrystalline diamond with reduced non‐diamond content
Authors: Remes Z. , Kromka A. , Vanecek M. 
Published: August 2009

AbstractOur nominally undoped nanocrystalline diamond (NCD) films were deposited on fused silica substrates by the microwave plasma enhanced chemical vapor deposition (MW CVD) at a relatively low temperature below 600 °C. They show high dark resistivity and measurable photosensitivity after surface oxidation. We present the “true” optical absorptance spectra calculated from transmittance T and reflectance R measurements corrected on the surface scattering and compare them with the normalized photocurrent spectra. The optical scattering does not allow to evaluate the small optical absorption in visible and near IR range from the T and R spectra. The photocurrent spectra were measured in the ultraviolet, visible, and near infrared optical range using the dual beam photocurrent spectroscopy (DBP) under constant UV illumination. Previously, NCD films often showed non‐diamond content with the photo‐ionization threshold at 0.8 eV increasing significantly the optical absorption in near IR and visible region. Here, we show that the non‐diamond content can be reduced by several orders of magnitude by depositing NCD on the carefully selected UV‐grade fused silica substrates under the optimized growth conditions followed by the post‐deposition chemical etching and cleaning. Unlike the NCD layers with high non‐diamond content, the NCD layers with reduced non‐diamond content are stable up to 450 °C.
Planarization of natural single crystal diamond polishing lines by microwave hydrogen plasma
Authors: Gaisinskaya A. , Edrei R. , Hoffman A. , Feldheim Y. 
Published: August 2009

AbstractThe effect of microwave hydrogenated (MW‐H) plasma exposure on the morphology of mechanically polished natural single crystal (100) oriented diamond type 2a surfaces is reported. It is shown that the surface morphology is very sensitive to plasma power and exposure time. Under appropriate plasma exposure conditions the diamond surfaces smooth out as reflected in the decrease in the number and depth of the polishing lines. A systematic study of the influence of hydrogen MW plasma power and exposure time on the diamond surface morphology is presented. The morphology of the diamond surfaces at the different stages was monitored with sub‐nano‐metric resolution by atomic force microscopy and scanning electron spectroscopy.
Thermoluminescence assessment of 0.5, 1.0 and 4.0 µm thick HFCVD undoped diamond films
Authors: Meléndrez R. , Chernov V. , May P. W. , Castañeda B. , Pedroza‐Montero M. , Barboza‐Flores M. 
Published: August 2009

AbstractChemical vapor deposition (CVD) diamond has not found extensive application as a thermoluminescence (TL) dosimeter, mainly because its TL glow curve shape is not reproducible. A slight variation in the growing conditions may result in strong changes in the morphology, microstructure, and surface‐impurity‐related defects, considerably affecting the TL glow curve features. In order to study the main TL characteristics under controlled growing conditions, we present results on three 0.5, 1.0, and 4.0 µm thick hot filament CVD (HFCVD) diamond films grown on Si (100) substrates. The recorded TL glow curves were resolved into individual peaks by a home‐made deconvolution program and the kinetic parameters of the peaks were extracted. The best fits of the TL glow curves were obtained using four peaks, except for the 4.0 µm thick sample that required five TL components. All samples showed three high intensity TL peaks between 180–400 °C and a less intense one or two peaks in the 100–180 °C low‐temperature region. The low‐temperature components all obey second‐order kinetics while the high‐temperature ones obey first and 1.6 order kinetics. The samples showed similar TL peaks with comparable kinetics parameters. It is concluded that the manufacturing of high quality HFCVD diamond may require a further improvement in the growing process in order to exploit its excellent tissue‐equivalence properties in clinical and medical applications.
Selective detection of phosgene by nanocrystalline diamond layer
Authors: Davydova Marina , Kromka Alexander , Exnar Petr , Stuchlik Martin , Hruska Karel , Vanecek Milan , Kalbac Martin 
Published: August 2009

AbstractNanocrystalline diamond (NCD) films were grown on gold/Al2O3 substrate using microwave plasma‐enhanced chemical vapor deposition (PECVD) process. The NCD morphology was controlled by the deposition time and it was investigated by scanning electron microscopy (SEM). Gas sensing properties of NCD surface conductivity to humid air, CO2, NH3, and COCl2 gases were measured by impedance measurements at room and at high temperature (140 °C). The H‐terminated NCD surface shows a significant response to oxidizing gas (humid air, COCl2) in comparison to reducing gases (CO2, NH3).
Spatial localization of Si‐vacancy photoluminescent centers in a thin CVD nanodiamond film
Authors: Basov A. A. , Rähn M. , Pärs M. , Vlasov I. I. , Sildos I. , Bolshakov A. P. , Golubev V. G. , Ralchenko V. G. 
Published: August 2009

AbstractA nanosized island‐like diamond film containing silicon‐vacancy (SiV) centers was grown by microwave plasma CVD on Si substrate. The diamond film was characterized by scanning electron microscope, microRaman, and photoluminescence spectroscopies. Nonuniform spatial localization of the SiV photoluminescent centers with a density over 1/µm2 in the photoemitting regions is found. Interfering factors hindering registration of emission from a single SiV center in thin CVD nanodiamond films are determined.
Study of leakage currents in PC CVD diamonds as function of the magnetic field
Authors: Müller S. , deBoer W. , Schneider M. , Sabellek A. , Schmanau M. , Rühle C. , Schneider T. , Hall‐Wilton R. 
Published: August 2009

AbstractPolycrystalline diamonds produced with the chemical vapor deposition technique (PC CVD diamonds) are regularly used as beam loss monitors in accelerators by measuring the ionization of the lost particles. In the past, these beam loss monitors showed sudden increase in the dark leakage current without beam loss and these erratic leakage currents were found to decrease, if magnetic fields were present. Here, we report on a systematic study of leakage currents inside a magnetic field. The decrease of erratic currents in a magnetic field was confirmed. On the contrary, diamonds without erratic currents showed an increase of the leakage current in a magnetic field perpendicular to the electric field for fields up to 0.6 T, for higher fields it decreases. A preliminary model is introduced to explain the observations.
Diamond Schottky p–n diode with high forward current density
Authors: Makino Toshiharu , Tanimoto Satoshi , Kato Hiromitsu , Tokuda Norio , Ogura Masahiko , Takeuchi Daisuke , Oyama Kazuhiro , Ohashi Hiromichi , Okushi Hideyo , Yamasaki Satoshi 
Published: August 2009

AbstractWe successfully fabricated a diamond diode, namely a Schottky p–n diode (SPND), which is composed of a fully depleted n‐type active layer sandwiched between a highly doped p‐type layer and a Schottky metal. The diamond SPND showed a high forward current density (over 4000 A cm−2 at 6 V) with a low built‐in voltage (∼1.5 V) at room temperature while maintaining a high rectification ratio of ∼1010. Further improvement of the high forward current density characteristics was found at high temperature. The SPND can be realized with higher forward current density than that of conventional diamond Schottky barrier diode, p–n diode, and recently proposed merged diodes, while maintaining the high rectification ratio.
Metal–insulator transition and superconductivity in highly boron‐doped nanocrystalline diamond films
Authors: Achatz P. , Bustarret E. , Marcenat C. , Piquerel R. , Dubouchet T. , Chapelier C. , Bonnot A. M. , Williams O. A. , Haenen K. , Gajewski W. , Garrido J. A. , Stutzmann M. 
Published: August 2009

AbstractThe low temperature electronic transport of highly boron‐doped nanocrystalline diamond films is studied down to 300 mK. The films show superconducting properties with critical temperatures Tc up to 2.1 K. The metal–insulator and superconducting transitions are driven by the dopant concentration and greatly influenced by the granularity in this system, as compared to highly boron‐doped single crystal diamond. The critical boron concentration for the metal–insulator transition lies in the range from 2.3 × 1020 up to 2.9 × 1020 cm−3, as determined from transport measurements at low temperatures. Insulating nanocrystalline samples follow an Efros–Shklovskii (ES) type of temperature dependence for the conductivity up to room temperature, in contrast to Mott variable range hopping (VRH) in the case of insulating single crystal diamond close to the metal–insulator transition. The electronic transport in the metallic samples not only depends on the properties of the grains (highly boron‐doped single crystal diamond), but also on the intergranular coupling between the grains. The Josephson coupling between the grains plays an important role for the superconductivity in this system, leading to a superconducting transition with global phase coherence at sufficiently low temperatures. Metallic nanocrystalline samples show similarities to highly boron‐doped single crystal diamond. However, metallic samples close to the metal–insulator transition show a richer behavior. In particular, a peak was observed in the low‐temperature magnetoresistance measurements for samples close to the transition, which can be explained by corrections to the conductance arising from superconducting fluctuations.
Chemogenomics: Looking at biology through the lens of chemistry
Authors: Doddareddy Munikumar R. , van Westen Gerard J. P. , van der Horst Eelke , Peironcely Julio E. , Corthals Frans , Ijzerman Adriaan P. , Emmerich Michael , Jenkins Jeremy L. , Bender Andreas 
Published: August 2009

AbstractChemogenomic approaches are gaining importance currently due to increased interest in the polypharmacology of drugs (i.e. their activity against multiple target proteins) and the ligand‐side relationships between different targets. This is not least due to the availability of increasingly larger amounts of ligand bioactivity data in the public domain; PubChem or the recent announcement to make the former Inpharmatica StARLITe database available through the EBI/EMBL being only the two of the many examples of this development. In this work we firstly summarize recent advances in the chemogenomics area. In the second part of the article we present current primary research origination from our group. This addresses various topics from the chemogenomics field such as substructure mining and chemogenomics analyses of GPCR ligands; novel feature selection methods such as two‐entropies analysis which are now translated from the bioinformatics into the chemogenomics field; as well as proteochemometric studies on subfamilies of G‐protein‐coupled receptors which not only take ligand and sequence information into account, but as a third variable are also able to consider quantitative activity values assigned to a ligand‐receptor pair. Copyright © 2009 Wiley Periodicals, Inc. Statistical Analysis and Data Mining 2: 149–160, 2009
Application of model selection technique in chemogenomic data analysis
Authors: Gao Xin , Lin Lina , Huang Ying 
Published: August 2009

AbstractWith the advent of high‐throughput chemogenomic data, it becomes crucially important to extract the important genes which influence the drug activities among the huge number of candidate genes. By employing model selection technique, especially designed for high‐dimensional data, we propose to develop a systematic approach to construct the network elucidating the dependency relationships among the drugs and the genes. Based on the extended Bayesian Information Criterion, we are able to select the best parsimonious network structure. A real National Cancer Institute (NCI)‐60 panel data set is analyzed to demonstrate the utility of the method. The biological implications of the results are discussed. Copyright © 2009 Wiley Periodicals, Inc. Statistical Analysis and Data Mining 2: 186–191, 2009
Survival attributable to an exposure
Authors: Cox Christopher , Chu Haitao , Muñoz Alvaro 
Published: August 2009

AbstractIn the survival analysis context, when an intervention either reduces a harmful exposure or introduces a beneficial treatment, it seems useful to quantify the gain in survival attributable to the intervention as an alternative to the reduction in risk. To accomplish this we introduce two new concepts, the attributable survival and attributable survival time, and study their properties. Our analysis includes comparison with the attributable risk function as well as hazard‐based alternatives. We also extend the setting to the case where the intervention takes place at discrete points in time, and may either eliminate exposure or introduce a beneficial treatment in only a proportion of the available group. This generalization accommodates the more realistic situation where the treatment or exposure is dynamic. We apply these methods to assess the effect of introducing highly active antiretroviral therapy for the treatment of clinical AIDS at the population level. Copyright © 2009 John Wiley & Sons, Ltd.
Does firm performance reveal its own causes? the role of Bayesian inference
Authors: Tang Ying‐Chan , Liou Fen‐May 
Published: August 2009

AbstractA central problem in strategic management is how the inference ‘sustainable competitive advantage generates sustainable superior performance’ can be put into practice. In this article we develop a theoretical framework to understand the causal relationships among (1) sustainable competitive advantage, (2) configuration, (3) dynamic capability, and (4) sustainable superior performance. We propose that a firm's competitive advantage, resource bundle configuration, and dynamic learning capability cannot be comprehended by outsiders. Its operational performance, however, can be captured by financial indicators. We promote an inductive Bayesian interpretation of the sustainable competitive advantage proposition. From this viewpoint, the presence or absence of competitive advantage may be reflected in the causal relationship between resource configuration, dynamic capability, and observable financial performance. We apply this theoretical framework to an example drawn from the global semiconductor industry, an area in which resource configuration and dynamic capability are essential to performance. The paper concludes with a summary of the proposed model and suggestions for future theoretical development of strategic management. Copyright © 2009 John Wiley & Sons, Ltd.