bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photo‐Induced Hydrogen Exchange Reaction between Methanol and Glyoxal: Formation of Hydroxyketene
Authors: Mielke Zofia , Mucha Małgorzata , Bil Andrzej , Golec Barbara , Coussan Stephane , Roubin Pascale 
Published: July 2008

AbstractWe study the structure and photochemistry of the glyoxal–methanol system (G–MeOH) by means of FTIR matrix isolation spectroscopy and ab initio calculations. The FTIR spectra show that the non‐hydrogen‐bonded complex, G–MeOH‐1, is present in an inert environment of solid argon. MP2/aug‐cc‐pVDZ calculations indicate that G–MeOH‐1 is the most stable complex among the five optimized structures. The interaction energy partitioned according to the symmetry‐adapted perturbation theory (SAPT) scheme demonstrates that the dispersion energy gives a larger contribution to the stabilization of a non‐hydrogen‐bonded G–MeOH‐1 complex than compared to the hydrogen‐bonded ones. The irradiation of G–MeOH‐1 with the filtered output of a mercury lamp (λ>370 nm) leads to its photo‐conversion into the hydroxyketene–methanol complex HK–MeOH‐1. The identity of HK–MeOH‐1 is confirmed by both FTIR spectroscopy and MP2/aug‐cc‐pVDZ calculations. An experiment with deuterated methanol (CH3OD) evidences that hydroxyketene is formed in a photo‐induced hydrogen exchange reaction between glyoxal and methanol. The pathway for the photo‐conversion of G–MeOH‐1 to HK–MeOH‐1 is studied by a coupled‐cluster method [CR–CC(2,3)]. The calculations confirm our experimental findings that the reaction proceeds via hydrogen atom exchange between the OH group of methanol and CH group of glyoxal.
Observation of the growth of carbon nanotubes prepared at low temperature
Authors: Gao Dawei , Liu Weiwei , Hou Li 
Published: July 2008

AbstractLack of information during the growth of carbon nanotubes has hindered efforts to understand the growth mechanism of these unique nanoscale structures. Here, we report that Multi‐walled carbon nanotubes with bamboo‐shaped structure may be synthesized by solvothermal method at 300°C using benzene as carbon source and Zn as catalyst. We have obtained direct experimental information on the growth under Transmission electron microscopy. It has been shown that all the compartments of bamboo‐like tube successively joined leading to the formation of regularly segmented nanobamboos. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of solvents on the hydrothermal formation of one‐dimensional magnesium hydroxide
Authors: Sun X. T. , Xiang L. , Zhu W. C. , Liu Q. 
Published: July 2008

AbstractThe influence of solvents on the hydrothermal formation of one‐dimensional (1D) magnesium hydroxide (Mg(OH)2) was investigated in this paper. Uniform 1D Mg(OH)2 with a length of 10‐20 μm, a width of 100‐200 nm and a preferential growth along [110] direction have been synthesized by treating magnesium oxysulfate (5Mg(OH)2·MgSO4·3H2O, abbreviated as 513MOS) nanowires in NaOH ethanol solution at 180 °C for 2.0 h. The experimental results indicated that the solvent of ethanol and NaOH concentration were essential for the conversion of 513MOS nanowires to 1D Mg(OH)2. The slow release of MgSO4 from 513MOS and the heterogenous precipitation of Mg(OH)2 at the defects left by MgSO4 dissolution promoted the formation of 1D Mg(OH)2. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth and characterization of strontium tartrate pentahydrate crystals
Authors: Firdous A. , Quasim I. , Ahmad M. M. , Kotru P. N. 
Published: July 2008

AbstractSilica gel impregnated with L‐tartaric acid and using strontium nitrate as the second reactant leads to the growth of well faceted strontium tartrate pentahydrate single crystals.The morphological developmen and internal cell dimensions are observed to be different from the ones reported in the literature for strontium tartrate trihydrate crystals. The crystals are characterized using XRD, CH analysis, SEM, FTIR spectroscopy and thermoanalytical techniques. The crystals are observed to be thermally stable upto about 105°C but thereafter start decomposing and ejecting water of hydration at various stages, finally reducing to strontium oxide. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Raman scattering characterization of Mn composition and strain in Ga1–xMnxSb/GaSb epitaxial layers
Authors: Islam M. R. , Chen N. F. , Yamada M. 
Published: July 2008

AbstractRaman scattering (RS) experiments have been performed for simultaneous determination of Mn composition and strain in Ga1–xMnxSb thin films grown on GaSb substrate by liquid phase epitaxy technique. The Raman spectra obtained from various Ga1–xMnxSb samples show only GaSb‐like phonon modes whose frequency positions are found to have Mn compositional dependence. With the combination of epilayer strain model, RS and energy dispersive x‐ray (EDX) experiments, the compositional dependence of GaSb‐like LO phonon frequency is proposed both in strained and unstrained conditions. The proposed relationships are used to evaluate Mn composition and strain from the Ga1–xMnxSb samples. The results obtained from the RS data are found to be in good agreement with those determined independently by the EDX analysis. Furthermore, the frequency positions of MnSb‐like phonon modes are suggested by reduced‐mass model. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The effect of Si/Al ratio of ZSM‐5 zeolite on its morphology, acidity and crystal size
Authors: Shirazi L. , Jamshidi E. , Ghasemi M. R. 
Published: July 2008

AbstractZSM‐5 zeolite crystal with different Si/Al molar ratios in the range of 10‐50 was synthesized using sodium silicate, aluminum sulfate and tetrapropylammonium bromide (TPA‐Br) as the organic template. The produced samples were characterized using XRD, FT‐IR, SEM and EDX techniques. All synthesized samples were found to be ZSM‐5 zeolite as confirmed by XRD and supported by FT‐IR. SEM results showed that ZSM‐5 synthesized with different Si/Al molar ratios had different morphologies and particle sizes. It was found that the average ZSM‐5 crystal size increased as Si/Al molar ratio increased. Thermogravimetric‐difference thermal analysis (TG‐DTA) technique was also used to measure the amount of template occluded inside the crystal pore. The synthesized Na‐ZSM‐5 was transformed into its acidic form, i.e., H‐ZSM‐5 using ion exchange method with ammonium nitrate solution. The H‐ZSM‐5 acidity was determined by NH3‐TPD. These results showed that different Si/Al molar ratios have effect on surface acidity of samples. The surface areas of the H‐ZSM‐5 were measured using BET method and the results showed that, decrease in Si/Al ratio, decreased the surface area. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
How do crystal lattice contacts reveal protein crystallization mechanism?
Authors: Nanev Christo N. 
Published: July 2008

AbstractThe nature of crystal lattice contacts is discussed because they reflect the selection of the most appropriate (for the given set of conditions) contact patches on the surface of protein molecules. The conclusion is that, along with chemical composition, the protein structure at the crystal lattice contacts is the key to crystallization behavior. The reason is that most stable are conformations, which do not only maximize the number of the bonds but simultaneously minimize van der Waals repulsions. A plausible explanation of the crystallization slot that exists for proteins is given on this basis. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Studies on multiphased mixed crystals of NaCl, KCl and KI
Authors: Priya M. , Mahadevan C. K. 
Published: July 2008

AbstractMultiphased mixed crystals of NaCl, KCl and KI were grown by the melt method, for the first time. Densities and refractive indices of all the grown crystals were determined and used for the estimation of the composition in the crystal. Atomic absorption spectroscopic measurements were done to estimate the metal atom contents in the crystal. Lattice parameters and thermal parameters (Debye‐Waller factor, mean square amplitude of vibration, Debye temperature and Debye frequency) were determined from the X‐ray powder diffraction data. DC and AC electrical measurements were done at various temperatures ranging from 40 to 150°C. Activation energies were also estimated. The observed lattice parameters showed that the system exhibits three phases each nearly corresponds to NaCl, KCl and KI. The thermal and electrical parameters show a highly nonlinear bulk composition dependence. Results are reported. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Highly Active Water‐Soluble Cross‐Coupling Catalyst Based on Dendritic Polyglycerol N‐Heterocyclic Carbene Palladium Complexes
Authors: Meise Markus , Haag Rainer 
Published: July 2008

AbstractA new water‐soluble polyglycerol derivative functionalized with N‐heterocyclic carbene palladium complexes was prepared and applied as catalyst for Suzuki cross‐coupling reactions in water. The complex displays a metal loading of around 65 metal centers per dendrimeric molecule, which is estimated to contain 130 chelating groups and thus corresponds approximately to the formation of 2:1 NHC/metal complexes. Monomeric analogues were also synthesized to validate the reactivity of the dendritic catalyst. Both types of catalysts were tested with various aryl bromides and arylboronic acids. Turnover frequencies of up to 2586 h−1 at 80 °C were observed with the dendritic catalyst along with turnover numbers of up to 59 000, which are among the highest turnover numbers reported for polymer‐supported catalysts in neat water. The dendritic catalyst could be used (reused) in five consecutive reactions without loss in activity.
Real‐time chaotic circuit stabilization via inverse optimal control
Authors: Jimenez Alexander , Sanchez Edgar N. , Chen Guanrong , Perez Jose P. 
Published: July 2008

AbstractIn this paper, an efficient approach is developed for real‐time global asymptotic stabilization of the chaotic Chen's circuit, as a typical example for chaotic circuit control. Based on a recently introduced methodology of inverse optimal control for nonlinear systems, a very simple stabilization control law, a linear state feedback, is electronically implemented for the desired global asymptotic stabilization. Both Chen's chaotic system and the designed controller are synthesized and realized by analog electronic components, with the aim of evaluating the physical performance of the real‐time control law and demonstrating the practicality of the control method, which is robust to some input uncertainties. Copyright © 2008 John Wiley & Sons, Ltd.
A configuration for realizing floating, linear, voltage‐controlled resistance, inductance and FDNC elements
Authors: Senani R. , Bhaskar D. R. , Gupta S. S. , Singh V. K. 
Published: July 2008

AbstractA configuration using current feedback amplifiers has been presented, which is capable of realizing linear, positive/negative voltage‐controlled resistance, voltage‐controlled inductance and voltage‐controlled frequency‐dependent negative conductance in floating form (and thereby, also in grounded form) from the same structure. The workability of the proposed configuration has been demonstrated by hardware implementation results using AD 844‐type current feedback op‐amps (CFOAs) and BFW‐11‐type JFETs and the workability in high‐frequency range has been demonstrated by SPICE simulation using CMOS CFOAs. Copyright © 2008 John Wiley & Sons, Ltd.
Flow cytometry histograms: Transformations, resolution, and display
Authors: Novo David , Wood James 
Published: July 2008

AbstractFlow cytometry data analysis routinely includes the use of one‐ or two‐parameter histograms to visualize the data. These histograms have traditionally been plotted with either a linear or logarithmic scale. However, the recent trend of performing the logarithmic conversion in software has made apparent some limitations of the traditional visual presentation of logarithmic data. This review discusses the mathematics of presenting data on a histogram and emphasizes the difference between scaling and binning. The review introduces the concept of an effective resolution to describe how the bin width changes in a variable bin‐width histogram. The change in effective resolution is used to explain the commonly observed valley and picket fencing artifacts. These result from the effective resolution of the display histogram being too high for the data being presented. Recently, several different binning transformations have been described that are becoming more popular because they allow one to view a large dynamic range of data on a single plot, while allowing the display of negative data values. While each of the transforms is based upon different equations, they all exhibit very similar properties. All of the transforms bin the data logarithmically at high channel values and linearly at low channel values. The linear scaling of the lower channels serves to limit the effective resolution of the histogram, thus minimizing the valley and picket fencing artifacts. The newer transformations are not without their own limitations and recommendations for the appropriate manner of presenting flow cytometry data using these newer transformations are discussed. © 2008 International Society for Advancement of Cytometry
Antigen‐specific B cell detection reagents: Use and quality control
Authors: Moody M. Anthony , Haynes Barton F. 
Published: July 2008

AbstractTests for immunoglobulin reactivity with specific antigens are some of the oldest and most used assays in immunology. With efforts to understand B cell development, B cell dysregulation in autoimmunity, and to generate B cell vaccines for infectious agents, investigators have found the need to understand the ontogeny and regulation of epitope‐specific B cell responses. The synchrony between surface and secreted antibodies for individual B cells has led to the development of reagents and techniques to identify antigen‐specific B cells via reagent interactions with the B cell receptor complex. B cell antigen‐specific reagents have been reported for model systems of haptens, for whole proteins, and for identification of double stranded (ds) DNA antibody‐producing B cells using peptide mimics. Here we provide an overview of reported techniques for the detection of antigen‐specific B cell responses via secreted antibody or by the surface B cell receptor and briefly discuss our recent work developing a panel of reagents to probe the B cell response to HIV‐1 envelope. We also present an analysis of strengths and weaknesses of various methods for flow cytometric analysis of antigen‐specific B cells. © 2008 International Society for Advancement of Cytometry
Development of an automated analysis system for data from flow cytometric intracellular cytokine staining assays from clinical vaccine trials
Authors: Shulman Nicholas , Bellew Matthew , Snelling George , Carter Donald , Huang Yunda , Li Hongli , Self Steven G. , McElrath M. Juliana , De Rosa Stephen C. 
Published: July 2008

AbstractIntracellular cytokine staining (ICS) by multiparameter flow cytometry is one of the primary methods for determining T‐cell immunogenicity in HIV‐1 clinical vaccine trials. Data analysis requires considerable expertise and time. The amount of data is quickly increasing as more and larger trials are performed, and thus there is a critical need for high‐throughput methods of data analysis. A web‐based flow cytometric analysis system, LabKey Flow, was developed for the analyses of data from standardized ICS assays. Using a gating template created manually in commercially available flow cytometric analysis software, the system automatically compensates and analyzes all data sets. Quality control queries were designed to identify potentially incorrect sample collections. Comparison of the semiautomated analysis performed by LabKey Flow and the manual analysis performed using FlowJo software demonstrated excellent concordance (concordance correlation coefficient > 0.990). Manual inspection of the analyses performed by LabKey Flow for eight‐color ICS data files from several clinical vaccine trials indicated that template gates can appropriately be used for most data sets. Thus, the semiautomated LabKey Flow analysis system can accurately analyze large ICS data files. Routine use of the system does not require specialized expertise. This high‐throughput analysis will provide great utility for rapid evaluation of complex multiparameter flow cytometric measurements collected from large clinical trials. © 2008 International Society for Advancement of Cytometry
Comparative study of human erythrocytes by digital holographic microscopy, confocal microscopy, and impedance volume analyzer
Authors: Rappaz Benjamin , Barbul Alexander , Emery Yves , Korenstein Rafi , Depeursinge Christian , Magistretti Pierre J. , Marquet Pierre 
Published: July 2008

AbstractRed blood cell (RBC) parameters such as morphology, volume, refractive index, and hemoglobin content are of great importance for diagnostic purposes. Existing approaches require complicated calibration procedures and robust cell perturbation. As a result, reference values for normal RBC differ depending on the method used. We present a way for measuring parameters of intact individual RBCs by using digital holographic microscopy (DHM), a new interferometric and label‐free technique with nanometric axial sensitivity. The results are compared with values achieved by conventional techniques for RBC of the same donor and previously published figures. A DHM equipped with a laser diode (λ = 663 nm) was used to record holograms in an off‐axis geometry. Measurements of both RBC refractive indices and volumes were achieved via monitoring the quantitative phase map of RBC by means of a sequential perfusion of two isotonic solutions with different refractive indices obtained by the use of Nycodenz (decoupling procedure). Volume of RBCs labeled by membrane dye Dil was analyzed by confocal microscopy. The mean cell volume (MCV), red blood cell distribution width (RDW), and mean cell hemoglobin concentration (MCHC) were also measured with an impedance volume analyzer. DHM yielded RBC refractive index n = 1.418 ± 0.012, volume 83 ± 14 fl, MCH = 29.9 pg, and MCHC 362 ± 40 g/l. Erythrocyte MCV, MCH, and MCHC achieved by an impedance volume analyzer were 82 fl, 28.6 pg, and 349 g/l, respectively. Confocal microscopy yielded 91 ± 17 fl for RBC volume. In conclusion, DHM in combination with a decoupling procedure allows measuring noninvasively volume, refractive index, and hemoglobin content of single‐living RBCs with a high accuracy. © 2008 International Society for Advancement of Cytometry
Association of glucose transporter 1 polymorphisms with type 2 diabetes in the Tunisian population
Authors: Makni K. , Mnif F. , Boudawara M. , Hamza N. , Rekik N. , Abid M. , Rebaï A. , Jarraya F. , Granier C. , Ayadi H. 
Published: July 2008

AbstractBackgroundT2DM is a complex metabolic disease. Genetic studies on T2DM have been of little help so far because several genetic association studies have shown conflicting results. In this study, we report the findings of a case‐control study on three SNPs in the GLUT1 gene. For this, we investigated the association of GLUT1 genotypes and haplotypes with T2DM.Research Design and MethodsAll 273 T2DM subjects (cases) and 343 healthy subjects (controls) were genotyped using the polymerase chain reaction restriction fragment length polymorphism.ResultsResults showed that the GT genotype ofXbaISNP could increase the risk of susceptibility to T2DM to 2.4 and that TAT is a ‘risk haplotype’ conferring a risk of 3.4 to T2DM.ConclusionThe TAT haplotype of the GLUT1 gene confers susceptibility to T2DM in the Tunisian population. Copyright © 2008 John Wiley & Sons, Ltd.
Increased renal collagen cross‐linking and lipid accumulation in nephropathy of Zucker diabetic fatty rats
Authors: Li Yuhao , Qi Yanfei , Kim Moon Sun , Xu Kevin Zhe‐Yang , Huang Tom Hsun‐Wei , Rong Xianglu , Murray Michael , Yamahara Johji 
Published: July 2008

AbstractBackgroundZucker diabetic fatty (ZDF) rat is a genetic model of type 2 diabetes and obesity. The mechanism underlying nephropathy in ZDF rats, however, remains unclear.MethodsZDF rats were compared to age‐matched Zucker lean (ZL) rats. Physiological and blood biochemical parameters, renal glomerular cross‐sectional area (hematoxylin‐eosin staining), fibrosis (van Giesen staining), collagen composition (Sircol Collagen Assay), lipids (enzymatic method) and mRNA expression (RT‐PCR) were determined.ResultsZDF rats showed an increase in renal‐insoluble collagen content and the ratio of renal‐insoluble to salt‐soluble collagen (2‐ and 1.5‐fold of the control animals). There were increases in renal glomerulosclerosis and interstitial fibrosis in ZDF rats (increased to 2‐fold) in the glomerular mesangium and tubulointerstitium, and increased glomerular area. Renal triglyceride accumulated to greater than 2‐fold of those levels in ZL rats. These changes were accompanied by hypoalbuminemia, and elevated plasma blood urea nitrogen and uric acid levels. Gene profiling showed increased expression of transcripts encoding the glomerulosclerotic mediator collagens I and IV, plasminogen activator inhibitor‐1, transforming growth factor‐β1, and angiotensin II type 1 receptor in ZDF rat kidney. Moreover, renal expression of mRNAs encoding sterol regulatory element‐binding protein‐1, a nuclear transcription factor that activates genes involved in fatty acid synthesis, and acetyl‐CoA carboxylase, a key enzyme that mediates fatty acid synthesis, was increased in ZDF rats.ConclusionsOur findings suggest that dysregulated gene expression may result in increased renal collagen cross‐linking and lipid accumulation, that may be associated with development of nephropathy in the animal model of type 2 diabetes and obesity. Copyright © 2008 John Wiley & Sons, Ltd.
Prevention of insulin resistance and beta‐cell loss by abrogating PKCε‐induced serine phosphorylation of muscle IRS‐1 in Psammomys obesus
Authors: Mack Esther , Ziv Ehud , Reuveni Hadas , Kalman Rony , Niv Masha Y. , Jörns Anne , Lenzen Sigurd , Shafrir Eleazar 
Published: July 2008

AbstractObjectivePsammomys obesus gerbil exhibits PKCε over‐expression on high‐energy (HE) diet. Muscle insulin receptor (IR) signalling and tyrosine kinase activity are inhibited eliciting insulin resistance. We aimed at preventing diabetes by inhibiting PKCε‐induced serine phosphorylation of IRS‐1 with novel PKCε abrogating peptides.Research designPKCε abrogating peptides were copied from catalytic domain of PKC molecule (PCT patent IL2006/000755). Psammomys fed a diabetogenic HE diet received i.p. peptides KCe‐12 and KCe‐16 (18 mg/kg) on days 0, 7 and 14 controls received peptide solvent.ResultsFood consumption and animal weight remained unchanged. On day 16, non‐fasting blood glucose levels returned to normal (90 ± 5 versus 347 ± 16 mg/dL in untreated controls). Hyperinsulinemia fell from 584 ± 55 to 180 ± 22 mU/L. Western blot analysis showed that the increased phosphoserine636, 639 content on IRS‐1 in gastrocnemius muscle of diabetic animals was reduced three fold, the PKB/AKT activity increased two fold and muscle GLUT4 tended to increase, compared with controls. Likewise, administration of KCe‐12 prior to placing the HE diet prevented the onset of diabetes. KCe‐12 treatment did not reduce muscle PKCε level. Damage and loss of insulin in pancreatic beta cells on HE diet were prevented by KCe‐12, as shown in micrographs of islet hematoxylin‐eosin staining and insulin immunostaining. The preserved secretory function enabled Psammomys to normalize glucose homeostasis.ConclusionsKCe‐16 and KCe‐12 peptides derived from PKCε substrate‐binding region prevented the nutritional diabetes and protected muscle IRS‐1 from PKCε‐induced serine phosphorylation, abrogating the insulin‐signalling impediment in the Psammomys model of type 2 diabetes. Anti‐diabetic peptides may lead to novel modalities preventing human overnutrition‐induced insulin resistance and diabetes. Copyright © 2008 John Wiley & Sons, Ltd.