bluuebunny/crossref_metadata_2025_split huggingface dataset:
Semi‐Classical Model of Strongly Correlated Coulomb Systems in Weak Magnetic Field
Authors: Ciftja O. 
Published: May 2010

AbstractThe integer and fractional quantum Hall effects are two remarkable macroscopic quantum phenomena occurring in two‐dimensional strongly correlated electronic systems at high magnetic fields and low temperatures. Quantization of Hall resistivity in the very high magnetic field regime at partial filling of the lowest Landau level indicates the stabilization of an electronic liquid quantum Hall phase of matter. Other interesting phases that differ from the quantum Hall phases take prominence in weaker magnetic fields when many more Landau levels are filled. These states manifest anisotropic magneto‐transport properties and, under certain conditions, appear to mimic charge density waves and/or liquid crystalline phases. One way to understand such a behavior has been in terms of effective interaction potentials confined to the highest Landau level partially filled with electrons. In this work we show that, for weak magnetic fields, such a quantum treatment of these strongly correlated Coulomb systems resembles a semi‐classical model of rotating electrons in which the time‐averaged interaction potential can be expressed solely in terms of guiding center coordinates. We discuss how the features of this semi‐classical effective potential may affect the stability of various strongly correlated electronic phases in the weak magnetic field regime (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Calculation of Canonical Properties and Excited States by Path Integral Numerical Methods
Authors: Vorontsov‐Velyaminov P. N. , Voznesenskiy M. A. , Polyakov E. A. , Lyubartsev A. P. 
Published: May 2010

AbstractPath integral Monte Carlo method in the expanded ensemble is used for calculation of the ratio of partition functions for different classes of permutations treating the problem of several interacting identical particles (fermions) in an external field. Wang‐Landau algorithm is used for adjustment of balancing factors. For systems consisting of greater than two number of particles we propose an advanced variant of our approach which implies calculation of the ratio of positive and negative contributions to the partition function.Densities and energies of the sequence of excited states starting from the ground state for a system of non interacting quantum particles are calculated in turn, one by one, by means of considering systems with artificially excluded lowest energy levels and further obtaining of the ”ground state” of each next system constructed in this way. The idea of evaluation of densities of excited states for a quantum system with interparticle interaction by evaluating density difference between systems of different number of noninteracting Fermi‐copies of the system of interest is realized in terms of cyclic expansion formalism for a simple 2D system of two spinless fermions interacting via Coulomb repulsion (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigation an Effective Interaction Potential of Dust Particles in Nonideal Dusty Plasma
Authors: Ramazanov T. S. , Kodanova S. K. , Daniyarov T. T. , Moldabekov Zh. A. 
Published: May 2010

AbstractInteraction between dusty particles remains to be an interesting issue that still requires deeper theoretical and experimental investigations. In the present paper we formulate a theoretical approach to the calculation of effective interaction potential of dust particles on the basis of Poisson equation and experimentally measured pair correlation functions. By application of our model to the data from the liquid phase of dust formations in stratified dc glow discharge, it is shown that there is an attractive component in the interaction of dust particle (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ordinary variations in human maternal caregiving in infancy and biobehavioral development in early childhood: A follow‐up study
Authors: Hane Amie Ashley , Henderson Heather A. , Reeb‐Sutherland Bethany C. , Fox Nathan A. 
Published: May 2010

AbstractRodent models of early caregiving find that pups reared by dams providing low levels of early stimulation subsequently display heightened stress reactivity and social aggression. We examined these effects in humans by investigating the effects of early caregiving on markers of biobehavioral development at ages 2 and 3 years. This study extended the findings reported by Hane and Fox (Hane and Fox [2006] Psychol. Sci. 17: 550–556) in which 185 mothers and infants were observed and scored for variations in maternal caregiving behavior (MCB) at age 9 months. Relative to young children who received high‐quality MCB in infancy, those who received low‐quality MCB showed significantly higher socially inhibited behavior with adults, right frontal electroencephalographam (EEG) asymmetry, aggressive play, and maternal reported internalizing behavior problems and anger proneness. These effects were independent of early temperamental reactivity. Results parallel rodent models and demonstrate that ordinary variations in MCB influence stress reactivity and social behavior in young children. © 2010 Wiley Periodicals, Inc. Dev Psychobiol 52: 558–567, 2010.
An improved Flp deleter mouse in C57Bl/6 based on Flpo recombinase
Authors: Kranz Andrea , Fu Jun , Duerschke Kristin , Weidlich Stefanie , Naumann Ronald , Stewart A. Francis , Anastassiadis Konstantinos 
Published: May 2010

AbstractRecently, a codon improved version of the Flpe site specific recombinase, termed Flpo, was reported as having greatly improved performance in mammalian cell applications. However, the degree of improvement could not be estimated because essentially no Flpe activity was observed. Here, we compare Flpe and Flpo accurately in a mammalian cell assay to estimate that Flpo is about five times more active than Flpe and similar to Cre and Dre. Consequently, we generated a Flpo deleter mouse line from the JM8 C57Bl/6 ES cells used in the EUCOMM and KOMP systematic knock‐out programs. In breeding experiments, we show that the Flpo deleter delivers complete recombination using alleles that are incompletely recombined by a commonly used Flpe deleter. This indicates that the Flpo deleter is more efficient. genesis 48:512–520, 2010. © 2010 Wiley‐Liss, Inc.
Influence of the hydrologic regime on resource availability in a semi‐arid stream‐riparian corridor
Authors: Harms Tamara K. , Grimm Nancy B. 
Published: May 2010

AbstractThe hydrologic regime of an ecosystem directly affects ecological processes by controlling water availability, but may also have indirect effects by influencing resource availability. To clarify interactions between the hydrologic regime and resource availability, we quantified the timescales over which precipitation and discharge correlated with abundance of dissolved carbon, nitrogen, and phosphorus in the stream–riparian corridor of the San Pedro River, a large desert river. We hypothesized that the hydrologic regime drives regimes of resource availability during flushing events caused by variation in source areas of run‐off generation. We also hypothesized that seasonal droughts may result in accumulation of resources within the catchment. Such accumulations would contribute to high solute concentrations in receiving waters following dry periods. To test these hypotheses, we compiled seasonal datasets over 4–6 years and used regression analyses to determine the temporal extents at which solute concentrations and transformations were correlated with precipitation and stream discharge. Concentrations of most biologically reactive solutes were unrelated to precipitation or discharge, suggesting overlapping influences of myriad biological and transport processes probably operating on event or shorter timescales. Concentration of phosphate [soluble reactive phosphate (SRP)], NO3−: SRP, and NO3−: NH4+in the stream were positively correlated with precipitation abundance over weeks and up to 2 months, supporting the flushing hypothesis. Microbial processes in floodplain soils responded to precipitation and discharge, suggesting that biological processes may mediate relationships between hydrology and resource availability. In this large, semi‐arid catchment, resource availability is linked to hydrology via hydrologic transport, flowpath characteristics, and biotic processing. Copyright © 2010 John Wiley & Sons, Ltd.
HLA‐F is a surface marker on activated lymphocytes
Authors: Lee Ni , Ishitani Akiko , Geraghty Daniel E. 
Published: May 2010

AbstractOf the three nonclassical class I antigens expressed in humans, HLA‐F has been least characterized with regard to expression or function. In this study, we examined HLA‐F expression focusing on lymphoid cells, where our previous work with homologous cell lines had demonstrated surface HLA‐F expression. HLA‐F protein expression was observed by Western blot analysis in all resting lymphocytes, including B cells, T cells, NK cells, and monocytes, all of which lacked surface expression in the resting state. Upon activation, using a variety of methods to activate different lymphocyte subpopulations, all cell types that expressed HLA‐F intracellularly showed an induction of surface HLA‐F protein. An examination of peripheral blood from individuals genetically deficient for TAP and tapasin expression demonstrated the same activation expression profiles for HLA‐F, but with altered kinetics post‐activation. Further analysis of CD4+CD25+ Treg showed that HLA‐F was not upregulated on the major fraction of these cells when they were activated, whereas CD4+CD25− T cells showed strong expression of surface HLA‐F when activated under identical conditions. These findings are discussed with regard to possible functions for HLA‐F and its potential clinical use as a marker of an activated immune response.
General Route to the Fabrication of ZnS and M‐Doped (M = Cd2+, Mn2+, Co2+, Ni2+, and Eu3+) ZnS Nanoclews and a Study of Their Properties
Authors: Dong Lihong , Liu Yang , Zhuo Yujiang , Chu Ying 
Published: May 2010

AbstractIn a mixed solvent composed of water and ethylenediamine, pure and ion‐doped (Cd2+, Mn2+, Co2+, Ni2+, Eu3+, etc.) clew‐like ZnS nanostructures, self‐assembled by curled ZnS nanowires, were synthesized by means of a hydrothermal route. These nanoclews possess a high specific surface area and can be separated easily from solution by natural settlement due to the self‐assembled structure; thus, they can be used in the field of photocatalysis. Photocatalytic experiments indicated that the pure ZnS nanoclews presented higher photocatalytic activity under UV irradiation, and the photocatalytic activity of the recycled ZnS nanoclews does not change noticeably after five reaction cycles. Furthermore, the CdxZn1–xS nanoclews showed high photocatalytic activity driven by visible light when the value of x was in the range from 0.3 to 0.7. The photoluminescence intensity of Eu3+‐doped ZnS nanoclews increased significantly compared with pure ZnS nanoclews. The formation mechanism of the ZnS nanoclews is also discussed.
Crystallization of Uranyl Salts from Dialkylimidazolium Ionic Liquids or Their Precursors
Authors: Cocalia Violina , Smiglak Marcin , Kelley Steven P. , Shamshina Julia L. , Gurau Gabriela , Rogers Robin D. 
Published: May 2010

AbstractThe interaction of uranyl nitrate hexahydrate with three ionic liquids and one ionic liquid precursor with minimal solvent addition led to the isolation and crystallographic characterization of four new uranyl salts: bis(1,3‐dimethylimidazolium) bis‐μ‐hydroxo‐bis[bis(nitrato‐O,O)dioxouranate(VI)], bis(1‐ethyl‐3‐methylimidazolium) bis‐μ‐hydroxo‐bis[bis(nitrato‐O,O)dioxouranate(VI)], bis(1,2,3‐trimethylimidazolium) bis‐μ‐hydroxo‐bis[bis(nitrato‐O,O)dioxouranate(VI)], and bis(1‐ethyl‐3‐methylimidazolium) trichlorobis(nitrato‐O,O)dioxouranate(VI). Each ion in the four isolated salts has precedence in the crystallographic literature, although the exact combinations of ions we observe in these salts are new. Some interesting differences in the packing of the ions can be related to the lack of an acidic C2‐H ring hydrogen atom in the 1,2,3‐trimethylimidazolium cation. It is suggested that future studies of these reactions be carried out under more strictly anhydrous conditions.
Pauson–Khand Reaction of Allenic Hydrocarbons: Synthesis of 4‐Alkylidenecyclopentenones
Authors: Antras Frédéric , Laurent Stéphane , Ahmar Mohammed , Chermette Henry , Cazes Bernard 
Published: May 2010

AbstractThe carbonyldicobalt‐mediated alkyne/allene/CO cocyclization gives 4‐alkylidenecyclopentenones as the major [2+2+1] cycloadducts. The regio‐ and stereoselectivities depend mainly on the substitution pattern of both the alkyne and the allenic moieties, which can be rationalized using the Magnus mechanism. However, contrary to this model, and in agreement with more recent mechanistic studies, our results provide evidence that both initial pseudo‐equatorial and pseudo‐axial coordination modes of the allenic hydrocarbons onto one of the cobalt atoms of the primary alkyne–dicobalt complex are involved. DFT calculations supporting both these coordination modes are given.
[C60(CN)5]–: A Remarkably Stable [60]Fullerene Anion
Authors: Troshin Pavel A. , Khakina Ekaterina A. , Peregudov Alexander S. , Konarev Dmitry V. , Soulimenkov Ilya V. , Peregudova Svetlana M. , Lyubovskaya Rimma N. 
Published: May 2010

AbstractReaction of C60Cl6 with organic cyanide yielded an ionic salt comprising the fullerene anion [C60(CN)5]–. This anion showed unprecedented stability in air and in solutions in the presence of water, organic and inorganic acids, and various electrophiles. The remarkable stability of the [C60(CN)5]– anion opens wide opportunities for the design of various air‐stable salts incorporating different cations (metallocene, tetrathiafulvalene, and etc.) that might reveal valuable magnetic or electronic properties and find wide application in the field of material science.
Metal‐Catalyzed Reactions between 2‐Azabicyclo[2.2.1]hept‐5‐en‐3‐ones and Arylboronic Acids
Authors: Abe Takumi , Takeda Hiroyuki , Takahashi Yumi , Miwa Yoshihisa , Yamada Koji , Ishikura Minoru 
Published: May 2010

AbstractCu‐ and Rh‐catalyzed coupling reactions of 2‐azabicyclo[2.2.1]hept‐5‐en‐3‐ones (1) with arylboronic acids were successful carried out under microwave irradiation conditions and yielded N‐aryl and C‐aryl derivatives of 1, respectively.
Unexpected Rearrangement Leading to Formation of a 1,3‐Bis(triphenylphosphonio)prop‐1‐en‐3‐idyl Carboxylate
Authors: Aitken R. Alan , Cleghorn Lee P. , Leitch Rebecca M. , Morrill Louis C. , Slawin Alexandra M. Z. 
Published: May 2010

AbstractWhereas biphenyl‐4,4′‐dicarbonyl dichloride reacts with methylenetriphenylphosphorane to give the expected bis(acylylide) 1, the same reaction of biphenyl‐2,2′‐dicarbonyl dichloride results in a multistep rearrangement leading to the zwitterionic 2‐[1,3‐bis(triphenylphosphonio)prop‐1‐en‐3‐id‐2‐yl]biphenyl‐2′‐carboxylate 2. X‐ray crystal structures of both 1 and 2 are reported.
Total Synthesis of Calystegine B4
Authors: Moosophon Panawan , Baird Morwenna C. , Kanokmedhakul Somdej , Pyne Stephen G. 
Published: May 2010

AbstractThe total synthesis of calystegine B4 was achieved in 10 steps from (–)‐D‐lyxose by using a new synthetic strategy to obtain the requisite protected hydroxylated 4‐aminocyclohept‐2‐en‐1‐one without the problem of regioisomer formation that was a problem in the earlier synthesis of this natural product. The key steps included a Petasis–borono‐Mannich reaction and a ring‐closing metathesis reaction.
Biooxidation of Primary Alcohols to Aldehydes through Hydrogen Transfer Employing Janibacter terrae
Authors: Orbegozo Thomas , de Vries Johannes G. , Kroutil Wolfgang 
Published: May 2010

AbstractChemoselective oxidations still represent a challenge for chemists. Lyophilized cells of Janibacter terrae were employed for the chemoselective oxidation of primary alcohols to the corresponding aldehydes by hydrogen transfer with the use of acetaldehyde as the hydrogen acceptor. Secondary alcohol moieties were transformed at a much slower rate. The substrate spectrum encompasses substituted benzyl alcohols, whereby substrates with a substituent in the meta position were well tolerated, whereas only very small substituents were tolerated in the ortho position. Furthermore, n‐alkanols and allylic alcohols were transformed with good conversions. The biocatalyst was compatible with DMSO as a water miscible organic solvent up to 30 % v/v.
Bicyclic Sultams with a Nitrogen at the Bridgehead and a Sulfur Atom in the Apex Position: Facile Preparation and Conformational Properties
Authors: Rassadin Valentin A. , Grosheva Daria S. , Tomashevskiy Aleksandr A. , Sokolov Viktor V. , Yufit Dmitry S. , Kozhushkov Sergei I. , de Meijere Armin 
Published: May 2010

AbstractA practical synthesis of bicyclic sultams with a pyramidal bridgehead nitrogen atom and a sulfur atom in the apex position has been elaborated. Compounds with 1‐azathiabicyclo[2.2.1]heptane (12a), ‐bicyclo[3.2.1]octane (12b, 12d), and ‐bicyclo[3.3.1]nonane (13b) skeletons were obtained by direct twofold inter/intramolecular alkylation of corresponding monocyclic sultams 9 and 10 with α,ω‐dihalides 11 in K2CO3/DMF in 56, 68, 52 and 52 % yield, respectively. On the other hand, a 1‐aza‐9‐thiabicyclo[4.2.1]nonane derivative (12c) could be prepared only by stepwise dialkylation in 24 % overall yield. Structural and conformational properties of four of the newly prepared bicyclic sultams in solution as well as in the solid state are discussed.
Directly Heated Bismuth Film Electrodes Based on Gold Microwires
Authors: Jacobsen Martin , Duwensee Heiko , Wachholz Falko , Adamovski Miriam , Flechsig Gerd‐Uwe 
Published: May 2010

AbstractAs a nontoxic substitute for mercury electrodes, bismuth electrodes attained a lot of attention during the last years. In this report we describe for the first time the preparation of two different directly heatable bismuth‐modified microwire electrodes. We characterized the electrochemical behaviour using cyclic voltammetry in acetate buffer and alkaline tartrate solution. The bismuth electrodes show a significantly wider potential window compared with bare gold wires. In the presence of picric acid as one example for the detection of explosives, the bismuth electrodes deliver higher signals. By applying heat during the measurements, the signals can be enhanced further. We used the temperature pulse amperometry (TPA) technique to improve the electrochemical response at the different types of electrodes. In this preliminary study, we were able to detect 3 ppm traces of picric acid.
Antimony Film Microelectrode for Anodic Stripping Measurement of Cadmium(II), Lead(II) and Copper(II)
Authors: Slavec Marija , Hocevar Samo B. , Baldrianova Lucie , Tesarova Eva , Svancara Ivan , Ogorevc Bozidar , Vytras Karel 
Published: May 2010

AbstractThe antimony film microelectrode (SbFME) is presented for measuring trace heavy metal ions in combination with anodic stripping voltammetry. The SbFME was tested in model solutions of 0.01 M HCl containing Cd(II) and Pb(II) in the presence of dissolved oxygen. The microsensor exhibited good linear behavior in the examined concentration range 20 μg L−1 to 100 μg L−1 and LoD of 1.9 and 3.1 μg L−1 for Cd(II) and Pb(II), respectively. The suitability of SbFME for measuring trace levels of Cu(II) was demonstrated using the standard reference material of natural water exploiting the sensor's specific characteristic of low re‐oxidation signal for antimony.
Voltammetric Determination of Glucose at Bismuth‐Modified Mesoporous Platinum Microelectrodes
Authors: Daniele Salvatore , Battistel Dario , Bergamin Simone , Bragato Carlo 
Published: May 2010

AbstractMesoporous platinum microeletrodes (MPtEs) modified by a mono‐ or submonolayer of adsorbed bismuth (Bi‐MPtE) were investigated and employed for the detection of glucose in 0.2 M NaOH solutions. The mesoporous platinum films were electrodeposited from hexachloroplatinic acid dissolved in the aqueous domain of the lyotropic liquid crystalline phase of octaethylene glycol monohexadecyl ether. Bismuth ad‐atoms were obtained by under potential deposition of Bi3+ ions in 0.5 M H2SO4 solutions. The coverage of the MPtEs by irreversibly adsorbed bismuth was checked in either a 0.5 M H2SO4 or 0.2 M NaOH solution free of Bi3+ ions, and exploiting the charge involved in the hydrogen adsorption/desorption peaks, which decreased in proportion to the amount of platinum sites covered by bismuth. The catalytic activity of a series of Bi‐MPtEs towards the oxidation of glucose was investigated by cyclic voltammetry, and the overall behaviour was found to be superior of that of the corresponding MPtEs. Also, at Bi‐MPtEs, the effect of interference by ascorbic acid was minimal. Calibration plots were examined over the glucose concentration range from 0.5 mM to 300 mM. It was found that linearity, between current against glucose concentration, and sensitivity depended on the electrode type and real surface area. At the Bi‐MPtEs both linear range and sensitivity were larger than those of the MPtEs. These results were discussed in terms of high tolerance of the Bi‐MPtEs towards the intermediate poisons originated in the electrooxidation process of glucose.
Cationic and anionic lipid‐based nanoparticles in CEC for protein separation
Authors: Nilsson Christian , Harwigsson Ian , Birnbaum Staffan , Nilsson Staffan 
Published: May 2010

AbstractThe development of new separation techniques is an important task in protein science. Herein, we describe how anionic and cationic lipid‐based liquid crystalline nanoparticles can be used for protein separation. The potential of the suggested separation methods is demonstrated on green fluorescent protein (GFP) samples for future use on more complex samples. Three different CEC‐LIF approaches for protein separation are described. (i) GFP and GFP N212Y, which are equally charged, were separated with high resolution by using anionic nanoparticles suspended in the electrolyte and adsorbed to the capillary wall. (ii) High efficiency (800 000 plates/m) and peak capacity were demonstrated separating GFP samples from Escherichia coli with cationic nanoparticles suspended in the electrolyte and adsorbed to the capillary wall. (iii) Three single amino‐acid‐substituted GFP variants were separated with high resolution using an approach based on a physical attached double‐layer coating of cationic and anionic nanoparticles combined with anionic lipid nanoparticles suspended in the electrolyte. The soft and porous lipid‐based nanoparticles were synthesized by a one‐step procedure based on the self‐assembly of lipids, and were biocompatible with a large surface‐to‐volume ratio. The methodology is still under development and the optimization of the nanoparticle chemistry and separation conditions can further improve the separation system. In contrast to conventional LC, a new interaction phase is introduced for every analysis, which minimizes carry‐over and time‐consuming column regeneration.