bluuebunny/crossref_metadata_2025 huggingface dataset:
Redesigning the Active Site of Transaldolase TalB from Escherichia coli: New Variants with Improved Affinity towards Nonphosphorylated Substrates
Authors: Schneider Sarah , Gutiérrez Mariana , Sandalova Tatyana , Schneider Gunter , Clapés Pere , Sprenger Georg A. , Samland Anne K.
Published: February 2010

Recently, we reported on a transaldolase B variant (TalB F178Y) that is able to use dihydroxyacetone (DHA) as donor in aldol reactions. In a second round of protein engineering, we aimed at improving the affinity of this variant towards nonphosphorylated acceptor aldehydes, that is, glyceraldehyde (GA). The anion binding site was identified in the X‐ray structure of TalB F178Y where a sulfate ion from the buffer was bound in the active site. Therefore, we performed site‐directed saturation mutagenesis at three residues forming the putative phosphate binding site, Arg181, Ser226 and Arg228. The focused libraries were screened for the formation of D‐fructose from DHA and d,l‐GA by using an adjusted colour assay. The best results with respect to the synthesis of D‐fructose were achieved with the TalB F178Y/R181E variant, which exhibited an at least fivefold increase in affinity towards d,l‐GA (KM=24 mM). We demonstrated that this double mutant can use D‐GA, glycolaldehyde and the L‐isomer, L‐GA, as acceptor substrates. This resulted in preparative synthesis of D‐fructose, D‐xylulose and L‐sorbose when DHA was used as donor. Hence, we engineered a DHA‐dependent aldolase that can synthesise the formation of polyhydroxylated compounds from simple and cheap substrates at preparative scale.
Size‐Tunable Highly Luminescent SiO2 Particles Impregnated with Number‐Adjusted CdTe Nanocrystals
Authors: Yang Ping , Murase Norio
Published: February 2010

Highly luminescent SiO2 particles impregnated with CdTe nanocrystals (NCs) are prepared by a sol–gel procedure. Partial ligand exchange from thioglycolic acid to 3‐mercaptopropyltrimethoxysilane (MPS) on the NCs enables retention of the initial photoluminescence (PL) efficiency of the NCs in water, while the simultaneous addition of a poor solvent (ethanol) results in regulated assembly of the NCs through condensation of hydrolyzed MPS. The SiO2 particles thus prepared have, for example, a diameter of 16 nm and contain three NCs each. The PL efficiency of these particles is 40 %, while the initial efficiency is 46 % in a colloidal solution. The redshift and narrowed spectral width in PL observed after impregnation indicate that the concentration of NCs in these nearly reaches the ultimate value (on the order of 1021 particles per liter). The porosity of these particles is investigated by means of N2 adsorption–desorption isotherms. Due to the SiO2 shell, these particles have higher stability in phosphate‐buffered saline buffer solution than the initial NCs. Their potential use for labeling in bio‐applications is investigated by conjugating biotinylated immunoglobulin G to them by using streptavidin maleimide as linker. Successful conjugation is confirmed by electrophoresis in agarose gel. This preparation method is an important step towards fabricating intensely emitting biocompatible SiO2 particles impregnated with semiconductor NCs.
Influence of photonic excitations on the electrical parameters of TlInS2 crystals
Authors: Qasrawi A. F. , Gasanly N. M.
Published: February 2010

The photo‐excitation effect on the current transport mechanism in TlInS2 crystals has been studied by means of dark and illuminated conductivity measurements. The temperature‐dependent electrical conductivity analysis in the temperature region of 110‐340 K revealed the domination of the thermionic emission and the thermally assisted variable range hopping (VRH) of charge carriers above and below 160 K, respectively. Above 160 K, the conductivity activation energies in the dark are found to be 0.28 and 0.15 eV in the temperature regions of 340‐240 K and 230‐160 K, respectively. In the temperature region of 110‐150 K, the dark variable range hopping analysis revealed a density of localized states of 1.99×1022 cm–3eV–1, an average hopping distance of 0.53 nm and an average hopping energy of 79.65 meV. When the sample was photo‐excited, the values of the conductivity activation energies, the density of localized states near the Fermi level and the average hopping energy were observed to decrease sharply with increasing illumination intensity. On the other hand, the average hopping distance increased with rising illumination intensity. Such behaviours were attributed to the Fermi level shift and/or trap density reduction by electron‐hole recombination. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fabrication and optical properties of two‐dimensional photonic crystal of ZnO pillars
Authors: Wu Wei , Yu Ke , Mao Huibing , Zhang Zhengli , Zhu Ziqiang
Published: February 2010

Two‐dimensional (2D) photonic crystal of ZnO pillars was synthesized on silicon substrate by the combination of template method and vapor‐phase transport method. The microstructure and morphology of the ZnO photonic crystal was evaluated by using scanning electron microscope (SEM) and X‐ray diffraction (XRD). Large‐area specular reflectance measurements showed the presence of photonic stop band. The effect of the photonic band gap and the special structure on the photoluminescence (PL) properties of ZnO photonic crystal has been investigated. Both suppression and enhancement in the PL were observed. Raman scattering analyses demonstrated that the defect of ZnO photonic crystal exists in this experiment. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Some structural considerations on the perovskite‐type A1‐ySryCo1‐xFexO3‐δ solid solution series
Authors: Magnone E. , Miyayama M. , Traversa E.
Published: February 2010

Solid solution series of La1‐ySryCo1‐xFexO3‐δ were extensively studied in the past as cathode materials for solid oxide fuel cells. However, the crystal structure behavior of La1‐ySryCo1‐xFexO3‐δ solid solution series when La‐ions are replaced with another rare‐earth ion or metallic alkaline earth metal is at present not fully understood. Here we report X‐ray powder diffraction measurements performed on samples of the Sm0.8Sr0.2Co1‐xFexO3‐δ solid solution series. This study demonstrates that the average A‐cation radius, as well as the Fe content (x), affects the structural modification of the A1‐ySryCo1‐xFexO3+δ solid solution series significantly. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Silicon transport under rotating and combined magnetic fields in liquid phase diffusion growth of SiGe
Authors: Armour N. , Dost S.
Published: February 2010

The effect of applied rotating and combined (rotating and static) magnetic fields on silicon transport during the liquid phase diffusion growth of SiGe was experimentally studied. 72‐hour growth periods produced some single crystal sections. Single and polycrystalline sections of the processed samples were examined for silicon composition. Results show that the application of a rotating magnetic field enhances silicon transport in the melt. It also has a slight positive effect on flattening the initial growth interface. For comparison, growth experiments were also conducted under combined (rotating and static) magnetic fields. The processed samples revealed that the addition of static field altered the thermal characteristics of the system significantly and led to a complete melt back of the germanium seed. Silicon transport in the melt was also enhanced under combined fields compared with experiments with no magnetic field. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Auslegungsfragen zur Energieeinsparverordnung. Fachkommission Bautechnik der Bauministerkonferenz. Teil 11
Authors: Achelis Justus
Published: February 2010

Die Bundesregierung hat auf Grund des § 1 Abs. 2, des § 2 Abs. 2 und 3, des § 3 Abs. 2, des § 4, jeweils in Verbindung mit § 5, sowie des § 5a Satz 1 und 2 des Energieeinsparungsgesetzes die “Verordnung zur Änderung der Energieeinsparverordnung” vom 29. April 2009 erlassen (BGBl. I 2009, S. 954 ff.).

Die geänderte Energieeinsparverordnung (“EnEV 2009”) ist am 01.10.2009 in Kraft getreten.

Um im Vollzug eine möglichst einheitliche Anwendung der Energieeinsparverordnung zu ermöglichen, hat die Fachkommission “Bautechnik” der Bauministerkonferenz beschlossen, eine Arbeitsgruppe einzurichten, die die in den Ländern eingehenden Anfragen von allgemeinem Interesse beantworten soll.

Die Entwürfe der Arbeitsgruppe werden dann in den Sitzungen der Fachkommission beraten.

Die Arbeitsgruppe wurde unter Beteiligung von Vertretern des Bundesministeriums für Verkehr, Bau und Stadtentwicklung, der Obersten Bauaufsichtsbehörden der Länder Bayern, Baden‐Württemberg, Brandenburg und Nordrhein‐Westfalen sowie des DIBt eingerichtet.

Die nachfolgend abgedruckten Anfragen und deren Antworten sind am 09.12.2009 in der wiedergegebenen Form beschlossen worden.
Anforderungen des Gesundheitsschutzes an Bauprodukte im Zulassungsverfahren am Beispiel der Bodenbeläge
Authors: Kirchner Doris , Dommaschk N. , Eichler A. , Tykiel V. , Kraeft C. , Misch W.
Published: February 2010

Seit 2004 erteilt das DIBt Zulassungen für Bodenbeläge zur Verwendung in Aufenthaltsräumen. Waren zunächst die Zulassungen direkt mit der Anforderung an die Schwerentflammbarkeit gekoppelt, so werden nun durch die fortschreitende Einführung harmonisierter Produktnormen immer mehr Zulassungen erteilt, die allein den Gesundheitsschutz regeln. Ein Novum am DIBt, denn bislang wurde der Umwelt‐ und Gesundheitsschutz zwar in vielen Zulassungsbereichen für Bauprodukte mitberücksichtigt, er war aber nie allein für die Zulassungspflicht maßgeblich.

Über diesen innovativen Zulassungsbereich, seine Entwicklung und zukünftige Herausforderungen soll im Folgenden ausführlich informiert werden.
Altered expression of miR‐17‐5p in CD4+ lymphocytes of relapsing–remitting multiple sclerosis patients
Authors: Lindberg Raija L. P. , Hoffmann Francine , Mehling Matthias , Kuhle Jens , Kappos Ludwig
Published: February 2010

MicroRNA (miRNA) are a class of post‐transcriptional regulators of gene expression targeting mRNA for translational repression and/or degradation. We analyzed the expression of 365 miRNA in lymphocytes in relapsing–remitting MS patients, and show the first evidence for distinct miRNA expression profiles in CD4+, CD8+ and B cells in MS when compared with those in healthy volunteers. MiR‐17‐5p, which is involved in autoimmunity, was up‐regulated in CD4+ cells from MS patients. This was correlated with alterations in the expression of potential target genes of miR‐17‐5p, i.e. phosphatase and tensin homology and phosphatidyl‐inositol‐3‐kinase regulatory subunit 1, which were down‐regulated upon stimulation of CD4+ cells with anti‐CD3/CD28 in vitro. Functional experiments with a synthetic inhibitor of miR‐17 supported the link between miRNA expression and the altered target gene expression. Moreover, we found distinct responses of deregulated miRNA to stimulation, i.e. miR‐17‐5p and miR‐193a were strongly up‐regulated, in contrast to the down‐regulation of miR‐497, miR‐1 and miR‐126. Other deregulated miRNA did not respond to the stimulation probably due to other, non‐T‐cell activation related, mechanisms in their mode of action. Our findings support the role of miRNA‐dependent regulatory mechanisms in the immunopathogenesis of MS.
Role of Treg in immune regulation of allergic diseases
Authors: Palomares Oscar , Yaman Görkem , Azkur Ahmet K. , Akkoc Tunc , Akdis Mübeccel , Akdis Cezmi A.
Published: February 2010

Allergy is a Th2‐mediated disease that involves the formation of specific IgE antibodies against innocuous environmental substances. The prevalence of allergic diseases has dramatically increased over the past decades, affecting up to 30% of the population in industrialized countries. The understanding of mechanisms underlying allergic diseases as well as those operating in non‐allergic healthy responses and allergen‐specific immunotherapy has experienced exciting advances over the past 15 years. Studies in healthy non‐atopic individuals and several clinical trials of allergen‐specific immunotherapy have demonstrated that the induction of a tolerant state in peripheral T cells represent a key step in healthy immune responses to allergens. Both naturally occurring thymus‐derived CD4+CD25+FOXP3+ Treg and inducible type 1 Treg inhibit the development of allergy via several mechanisms, including suppression of other effector Th1, Th2, Th17 cells; suppression of eosinophils, mast cells and basophils; Ab isotype change from IgE to IgG4; suppression of inflammatory DC; and suppression of inflammatory cell migration to tissues. The identification of the molecules involved in these processes will contribute to the development of more efficient and safer treatment modalities.
Hydrothermal Synthesis of a CaNb2O6 Hierarchical Micro/Nanostructure and Its Enhanced Photocatalytic Activity
Authors: Zhang Yingwei , Liu Chao , Pang Guangsheng , Jiao Shihui , Zhu Shiyao , Wang Dong , Liang Daxin , Feng Shouhua
Published: February 2010

A novel CaNb2O6 hierarchical micro/nanostructure was successfully fabricated under mild hydrothermal conditions in the absence of templates or organic additives. In this hierarchical micro/nanostructure, the nanosheets grow vertically on the surface of the one‐dimensional microneedles whose axial direction is along the c‐axis, and the single crystalline nanosheets are parallel to the (020) planes. A two‐step nucleation–growth mechanism is proposed to explain the formation of the CaNb2O6 hierarchical micro/nanostructure, based on the observation of a time‐dependent morphology evolution process. The hierarchically structured CaNb2O6 exhibits a stronger enhancement of photocatalytic activity in the degradation of rhodamine B (RhB) than other morphological CaNb2O6 samples, such as nanoparticles, nanoribbons, and microneedles. This simple hydrothermal method provides a new general approach for the synthesis of potentially useful niobates.
Mixed Tellurides Ni3–xGaTe2 (0 ≤ x ≤ 0.65): Crystal and Electronic Structures, Properties, and Nickel Deficiency Effects on Vacancy Ordering
Authors: Isaeva Anna A. , Makarevich Olga N. , Kuznetsov Alexey N. , Doert Thomas , Abakumov Artem M. , Van Tendeloo Gustaaf
Published: February 2010

The Ni3–xGaTe2 series of compounds (0 ≤ x ≤ 0.65) was synthesized by a high‐temperature ceramic technique at 750 °C. Crystal structures of three compounds in the series were determined by X‐ray powder diffraction: Ni2.98(1)GaTe2 (RI = 0.042, Rp = 0.023, Rwp = 0.035), Ni2.79(1)GaTe2 (RI = 0.053, Rp = 0.028, Rwp = 0.039), Ni2.58(1)GaTe2 (RI = 0.081, Rp = 0.037, Rwp = 0.056); the structures were verified by electron diffraction and, for the former compound, high‐resolution electron microscopy. The compounds crystallize in a hexagonal lattice with P63/mmc, and the structures can be regarded as a hexagonal close‐packed array with a –Ga–Te–Te– stacking sequence. The octahedral and trigonal bipyramidal voids in the hcp structure are selectively filled with Ni atoms to form one entirely occupied and two partially occupied sites, thus allowing variations in the nickel content in the series of compounds Ni3–xGaTe2 (0 ≤ x ≤ 0.65). A superstructure with asup = 2asub (P63/mmc) has been identified for Ni3–xGaTe2 (0.5 ≤ x ≤ 0.65) by electron diffraction. Real‐space, high‐resolution images confirm an ordering of Ni atoms and vacancies inthe ab plane. Quantum‐chemical calculations performed forNi3–xGaTe2 (x = 0, 0.25, 0.75, 1) suggest anisotropic metallic conductivity and Pauli paramagnetic behavior that are experimentally confirmed for Ni3GaTe2.
Synthesis of Triazolyl‐Substituted 3‐Aminopiperidines by Huisgen‐1,3‐Dipolar Cycloaddition – New Scaffolds for Combinatorial Chemistry
Authors: Schramm Heiko , Saak Wolfgang , Hoenke Christoph , Christoffers Jens
Published: February 2010

Orthogonally N‐protected (Boc and Cbz) 4‐(1,2,3‐triazol‐4‐yl)‐substituted 3‐aminopiperidines are new scaffolds for combinatorial chemistry. They were prepared from a piperidine building block by a sequence of nucleophilic aziridine ring opening with NaN3 and subsequent copper‐catalyzedHuisgen 1,3‐dipolar cycloaddition with ten different alkynes. Constitution and relative configuration of the major as well as minor products were established by single‐crystal X‐ray structure analysis of bromophenylsulfonyl derivatives.
Indole as Neutral Leaving Group in Silver Nitrate Induced Cyclization Reactions of N‐{2‐[Alkynyl(hetero)aryl]methylene}indolin‐1‐amines for the Synthesis of Annulated Pyridine Derivatives
Authors: Ghavtadze Nugzar , Fröhlich Roland , Würthwein Ernst‐Ulrich
Published: February 2010

N‐{2‐[Alkynyl(hetero)aryl]methylene}indolin‐1‐amines 3 undergo, upon treatment with silver nitrate in chloroform at 60 °C, electrophilic cyclization reactions to afford annulated pyridine derivatives 4. Mechanistically, the silver(I)‐assisted 6‐endo‐dig ring‐closure process of compounds 3 leads to the formation of an intermediate pyridinium cation, which releases – besides the products 4 – indole as unusual but efficient neutral leaving group after N–N bond cleavage. It is shown that among the hydrazones studied, only the 1‐aminoindoline‐derived substrates N‐{2‐[alkynyl(hetero)aryl]methylene}indolin‐1‐amines 3 are suitable to produce annulated pyridine derivatives 4 in high yield. The reaction can be performed in air and even in the presence of water in the reaction medium. Since during the course of the reaction indole is oxidized by the silver(I) ions, stoichiometric amounts of silver salt are required. Quantum chemical calculations have been applied in order to gain additional information on the reaction mechanism and the key reactive intermediates.
Naphthyl methacrylate‐based monolithic column for RP‐CEC via hydrophobic and π interactions
Authors: Karenga Samuel , El Rassi Ziad
Published: February 2010

A neutral naphthyl methacrylate‐based monolith (NMM) was introduced for RP‐CEC of various aromatic compounds via hydrophobic and π interactions. It was characterized over a wide range of elution conditions to gain insight into its RP retention mechanism toward the various solute probes under investigation. First, the NMM column exhibited cathodal EOF at various mobile phase compositions and pH suggesting that although the NMM column is void of fixed charges, it acquires a negative zeta potential. It is believed that the negative zeta potential is imparted by the adsorption of mobile phase ions to the NMM surface. The NMM column exhibited π–π interactions in addition to hydrophobic interactions due to the aromatic and nonpolar nature of its naphthyl ligands. In all cases, the retention of the various aromatic test solutes including PAHs, benzene derivatives, toluene derivatives, anilines and toluidine, tolunitrile and nitrotoluene positional isomers on the NMM column were compared to their retention on an octadecyl acrylate‐based monolithic column. Not only were the values of the retention factors of the various solutes on the NMM column higher than those obtained on the octadecyl acrylate‐based monolithic column under otherwise the same CEC conditions, but the elution orders were also different on both columns with a superior and unique selectivity exhibited by the NMM column.
Spontaneous pneumomediastinum in anorexia nervosa: A case report and review of the literature on pneumomediastinum and pneumothorax
Authors: Hochlehnert Achim , Löwe Bernd , Bludau Hans‐Bernd , Borst Mathias , Zipfel Stephan , Herzog Wolfgang
Published: February 2010

We report a case of a 20‐year‐old white woman with the history of anorexia nervosa presenting with spontaneous pneumomediastinum (SPM). On admission, her body mass index (BMI) was 9.9 kg/m2. Physical examination revealed subcutaneous crepitation especially in the axillae, the intercostal spaces, between the scapulae and along the spine. A chest X‐ray showed extensive tissue emphysema, especially in the upper mediastinum. In a computed tomography (CT) scan, additional air was found in the upper retroperitoneal space adjacent to the stomach and to the left of the aorta. The patient recovered clinically within three weeks, and a CT scan showed a complete remission of the pneumomediastinum and subcutaneous emphysema. Based on this, case review of the literature about the frequency of pneumomediastinum in young patients with low weight is presented concerning epidemiology, etiology, symptoms, diagnosis, treatment, time to recovery and prognosis. Copyright © 2010 John Wiley & Sons, Ltd and Eating Disorders Association.
Binge eating disorder in a Chinese male—A case report
Authors: Chen C. K. , Tao Z. L.
Published: February 2010

Objective

There are reports in China about males suffering from anorexia nervosa and bulimia nervosa, but hitherto no report of binge eating disorder (BED).

Method

This case report describes the history, symptom progression and treatment of a male suffering from BED.

Results

Many Chinese people who come from rural areas try to integrate in the urban life. Regardless of their level of education many suffer various difficulties, which can trigger psychological disorders. Copyright © 2010 John Wiley & Sons, Ltd and Eating Disorders Association.
Thermally developing flow in finned double‐pipe heat exchanger
Authors: Iqbal Mazhar , Syed K. S.
Published: February 2010

A numerical solution of the convective heat transfer in the thermal entry region of the finned double‐pipe is carried out for the case of hydro‐dynamically fully developed flow when subjected to uniform wall temperature boundary condition. Adaptive axial grid size is used in order to cater for the variation of large solution gradients in the axial direction. It has been observed that the thermal entrance region is highly effective and there is a substantial enhancement in the heat transfer coefficient. A maximum of 76.4877% increase has been observed in the thermal entrance region as compared with the fully developed region for 24 fins and H*=0.6 when R̂=0.25, whereas for R̂=0.5 the maximum increase is 75.0308% for the same number of fins of same height. It has been observed that no geometry consistently perform better throughout the entrance region. However, the geometries that have optimal performance in the fully developed region perform better in the developing region on average terms. Results show that the Nusselt number and the thermal entrance length are dependent upon various geometrical parameters such as ratio of radii of the inner and the outer pipe, fin height and the number of fins. The limiting case results match well with the literature results. This validates our numerical procedure and computer code. Copyright © 2010 John Wiley & Sons, Ltd.
Information flux maximum‐entropy approximation schemes for convection–diffusion problems
Authors: Cyron Christian J. , Nissen Keijo , Gravemeier Volker , Wall Wolfgang A.
Published: February 2010

The requirement for stabilization or other similar techniques is well known when using the finite element method in computational fluid mechanics. A variety of such techniques has been introduced during the past decades along with different physical interpretations of the stabilization terms employed. In introducing so‐called information flux methods, we developed a new point of view on the problem of numerical instabilities; with respect to Shannon's information theory instabilities are interpreted as a consequence of unadequate observance of the information flux present in fluid mechanics. Here we discuss different approaches to setting up information flux maximum‐entropy approximation schemes based on that idea. The good accuracy of these approximation schemes is demonstrated for convection–diffusion problems by means of several linear, time‐independent one‐ and two‐dimensional numerical examples and comparisons with state‐of‐the‐art stabilized finite element methods. Copyright © 2010 John Wiley & Sons, Ltd.
Atypical mRNA fusions in PML‐RARA positive, RARA‐PML negative acute promyelocytic leukemia
Authors: Walz Christoph , Grimwade David , Saussele Susanne , Lengfelder Eva , Haferlach Claudia , Schnittger Susanne , Lafage‐Pochitaloff Marina , Hochhaus Andreas , Cross Nicholas C. P. , Reiter Andreas
Published: February 2010

Reciprocal RARA‐PML transcripts are not detected in ∼25% of patients with PML‐RARA positive acute promyelocytic leukemia (APL), but the reasons for this are poorly understood. We studied 21 PML‐RARA positive/RARA‐PML negative cases by bubble PCR and multiplex long template PCR to identify the genomic breakpoints. Additional RT‐PCR analysis was performed based on the DNA findings. Three cases were found to have complex rearrangements involving a third locus: the first had a PML‐CDC6‐RARA forward DNA fusion and expressed a chimeric PML‐CDC6‐RARA mRNA in addition to a PML‐RARA. The other two had HERC1‐PML and NT_009714.17‐PML genomic fusion sequences at their respective reciprocal breakpoints. Six patients were falsely classified as RARA‐PML negative due to deletions on chromosome 15 and/or 17, or alternative splicing leading to atypical RARA‐PML fusion transcripts, which were not identified by conventional RT‐PCR assays. This study demonstrates that the frequency of RARA‐PML expression has been underestimated and highlights remarkable complexity at chromosomal breakpoint regions in APL even in cases with an apparently simple balanced t(15;17)(q24;q12). © 2010 Wiley‐Liss, Inc.
Transcriptional upregulation of nitric oxide synthase II by nuclear factor‐κB promotes apoptotic neuronal cell death in the hippocampus following experimental status epilepticus
Authors: Chuang Yao‐Chung , Chen Shang‐Der , Lin Tsu‐Kung , Chang Wen‐Neng , Lu Cheng‐Hsien , Liou Chia‐Wei , Chan Samuel H.H. , Chang Alice Y.W.
Published: February 2010

Whereas status epilepticus, or the condition of continuous epileptic seizures, produces a characteristic pattern of preferential neuronal cell loss in the hippocampus, the underlying mechanism is still unsettled. Based on an experimental model of temporal lobe status epilepticus, we demonstrated previously that prolonged seizures prompted an overproduction of nitric oxide (NO) by upregulation of NO synthase II (NOS II) in the hippocampal CA3 subfield, followed by the activation of mitochondrial apoptotic signaling cascade. Using the same animal model, the present study evaluated the hypothesis that transcriptional upregulation of NOS II gene by nuclear factor‐κB (NF‐κB) promotes apoptotic neuronal cell death in the hippocampus following status epilepticus. In Sprague‐Dawley rats, significantly augmented nucleus‐bound translocation of NF‐κB p50 and p65 subunits and DNA binding activity of NF‐κB were observed in hippocampal CA3 neurons as early as 30 min after elicitation of sustained seizure activity by microinjection of kainic acid into the CA3 subfield, followed by a progressive elevation that peaked at 90 min. In addition, application bilaterally into the hippocampal CA3 subfield of a selective NF‐κB inhibitor, pyrrolidine dithiocarbamate or double‐stranded κB decoy DNA significantly antagonized the activated NOS II‐peroxynitrite signaling cascade (3 hr) and the associated manifestations of apoptotic cell death (7 days) in the hippocampus. We conclude that activation of NF‐κB in hippocampal CA3 neurons upregulates NOS II gene expression following experimental temporal lobe status epilepticus, leading to apoptotic neuronal cell death in the hippocampus. © 2010 Wiley‐Liss, Inc.
Gristhorpe Man: a Raman spectroscopic study of ‘mistletoe berries’ in a Bronze Age log coffin burial
Authors: Edwards Howell G. M. , Montgomery Janet , Melton Nigel D. , Hargreaves Michael D. , Wilson Andrew S. , Carter Elizabeth A.
Published: February 2010

In 1834 in a tumulus at Gristhorpe, North Yorkshire, UK, an intact coffin fashioned from the hollowed‐out trunk of an oak tree was found to contain a well‐preserved skeleton stained black from the oak tannins, wrapped in an animal skin and buried with a range of grave artefacts, including a bronze dagger, flints and a bark vessel. The remains were deposited in the Rotunda Museum at Scarborough, where closure due to refurbishment in 2005–2008 provided an opportunity for the scientific investigation of the skeletal remains and artefacts using a wide range of techniques. Dendrochronological and radiocarbon dating has established the age of the skeleton as 2140–1940 BC at 95% confidence, in the Early Bronze Age. As part of this project, Raman spectra of several mysterious small spherical objects discovered in the coffin underneath the skeleton and initially believed to be ‘mistletoe berries’ associated with ancient burial customs have been recorded non‐destructively. The interpretation of the Raman spectral data, microscopic analysis and comparison with modern specimens has led to the conclusion that the small spheres are phosphatic urinary stones, which reflect the archaeological dietary evidence and stable isotope analysis of bone collagen of Gristhorpe Man. Copyright © 2010 John Wiley & Sons, Ltd.
Quantification of lamivudine in human plasma by hydrophilic interaction chromatography‐tandem mass spectrometry
Authors: Ji Hye Young , Lee Hye Won , Yoon Young‐Ran , Lee Hye Suk
Published: February 2010

A rapid, selective and sensitive method for the determination of lamivudine in human plasma was developed using hydrophilic interaction chromatography‐MS/MS. This method involved protein precipitation with acetonitrile as sample preparation procedure. Lamivudine and famotidine (internal standard) were analyzed on a Luna hydrophilic interaction chromatography column with the mobile phase of acetonitrile/10 mM ammonium formate (95:5, v/v) and detected using electrospray ionization mass spectrometry in the selected reaction monitoring mode. The standard curve was linear (r2=0.9985) over the concentration range of 50–3000 ng/mL. The lower limit of quantification was 50 ng/mL using 50 μL of plasma sample. The coefficient of variation and relative error for intra‐ and inter‐assay at four quality control levels were 2.1–7.5 and −4.0 to 3.3%, respectively. The absolute and relative matrix effects for lamivudine and famotidine were practically absent. The present method was successfully applied to the pharmacokinetic study of lamivudine after oral dosing of lamivudine (100 mg tablet) to male healthy volunteers.
In situ Self‐Assembly of Zigzag Polyimide Chains to Crystalline Branched Supramolecular Structures with High Surface Area
Authors: Zeng Shaozhong , Guo Limin , Cui Fangming , Gao Zhe , Zhou Jian , Shi Jianlin
Published: February 2010

Crystalline‐branched supramolecular structures (CBSSs) with surface area (Brunauer‐Emmett‐Teller model) up to 350 m2 · g−1 were synthesized by in situ self‐assembly of the zigzag polyimide macromolecules under solvent‐thermal condition. The pore formation mechanism in these polyimides was supposed to be different from any microporous polymers ever reported. Although this family of porous polyimide does not belong to covalent organic frameworks (COFs), their high degree of crystallinity shows the possibilities that the dynamic covalent chemistry for synthesizing COFs could be extended from easily hydrolyzable BO bond to a more stable imido bond. Therefore, we believe that these CBSSs could be useful in many applications, e.g., catalyst carriers and low‐K materials.

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Dendritic Macromolecules as Inhibitors to Protein‐Protein Binding
Authors: Chiba Fumiko , Hu Ting Chou , Twyman Lance J. , Wagstaff Mark
Published: February 2010

Summary: Our initial studies into protein binding using a series of dendrimers as size selective inhibitors have been described. Two different proteins, cytochromo‐c and chymotrypsin have been selected for these binding experiments.
Oligomeric Branched Polyethers with Multiple Hydroxyl Groups by Cationic Ring‐Opening Polymerization for Inorganic Surface Modification
Authors: Bednarek Melania , Pluta Mirosław
Published: February 2010

Summary: Cationic ring‐opening polymerization of cyclic ethers (also esters and acetals) substituted with hydroxyl groups leads to branched multihydroxyl polymers. When 4‐membered hydroxysubstituted oxetanes or 5‐membered hydroxysubstuituted oxolanes (or lactone and 1,3‐dioxolane) are used as monomers the polymerization products have limited molecular weights (about 1000). Polymerization of these monomers leading in situ to oligomeric products was used for inorganic surface modification. Successful polymerizations of oxetane as well as considered as difficult to polymerize 5‐membered hydroxysubstituted cyclic monomers initiated from montmorillonite clay and silica nanoparticles surfaces were performed.
Towards physics‐oriented smoothing in algebraic multigrid for systems of partial differential equations arising in multi‐ion transport and reaction models
Authors: Thum Peter , Clees Tanja
Published: February 2010

Algebraic multigrid (AMG) methods offer an efficient solution technique for many industrial applications. However, the employment of AMG for physically involved systems of partial differential equations comprising convection, diffusion, migration (drift) and reaction terms is rather new. For such applications, point‐based AMG (PAMG) methods are promising preconditioners. This paper focuses on developing a reordering framework for PAMG's smoothing, which is oriented on physical properties of systems arising in an electrochemical multi‐ion transport and reaction model. Level‐dependent, alternating smoothing is used. Numerical results are presented for a range of electrochemical test cases with scientific and industrial relevance demonstrating the robustness of the new framework. Overall, the results clearly indicate the usefulness and potentials of a physics‐oriented smoothing framework. Copyright © 2010 John Wiley & Sons, Ltd.
Acute metal stress in Populus tremula×P. alba (717‐1B4 genotype): Leaf and cambial proteome changes induced by cadmium2+
Authors: Durand Thomas C. , Sergeant Kjell , Planchon Sébastien , Carpin Sabine , Label Philippe , Morabito Domenico , Hausman Jean‐François , Renaut Jenny
Published: February 2010

The comprehension of metal homeostasis in plants requires the identification of molecular markers linked to stress tolerance. Proteomic changes in leaves and cambial zone of Populus tremula×P. alba (717‐1B4 genotype) were analyzed after 61 days of exposure to cadmium (Cd) 360 mg/kg soil dry weight in pot‐soil cultures. The treatment led to an acute Cd stress with a reduction of growth and photosynthesis. Cd stress induced changes in the display of 120 spots for leaf tissue and 153 spots for the cambial zone. It involved a reduced photosynthesis, resulting in a profound reorganisation of carbon and carbohydrate metabolisms in both tissues. Cambial cells underwent stress from the Cd actually present inside the tissue but also a deprivation of photosynthates caused by leaf stress. An important tissue specificity of the response was observed, according to the differences in cell structures and functions.
Formation & evolution of cosmic superstrings: a short review
Authors: Sakellariadou M.
Published: February 2010

I will briefly review the formation and evolution of cosmic superstrings, in the context of brane‐world cosmological models within M‐theory. These objects can play the rôle of cosmic strings, offering a variety of astrophysical consequences, which I will briefly discuss.
Asymptotic helicity conservation in SUSY
Authors: Gounaris G.J. , Layssac J. , Renard F.M.
Published: February 2010

We summarize the extensive work started in [1], according to which total helicity is conserved for any two‐to‐two process, at sqrt s >> MSUSY and fixed angles, in any SUSY extension of SM. Asymptotically the theorem is exact. But it may also have important implications at lower energies

. Up to now, these have been investigated to 1loop electroweak (EW) order for the processes

; as well as the 17 gg → HH', and the 9 gg → VH processes, where H,H' denote Higgs or Goldstone bosons, and V = Z, W±.
The effective actions of pseudoscalar and scalar particles in theories with gauge and conformal anomalies
Authors: Armillis R. , Corianò C. , Delle Rose L. , Guzzi M. , Mariano A.
Published: February 2010

We review recent work on the effective field theory description and the phenomenology of axion‐like and scalar particles in models characterized by gauge and/or conformal anomalies.
Auxetic properties of polycrystals
Authors: Jasiukiewicz Cz. , Paszkiewicz T. , Wolski S.
Published: February 2010

Young's and shear moduli and Poisson's ratio of polycrystalline solids consisting of two‐dimensional quadratic and three‐dimensional cubic randomly oriented grains of the same size and shape is studied. Considered polycrystals are initially unstrained. It is shown that for such polycrystals the division of the mechanical stability regions into areas of various auxeticity properties is different than for monocrystalline solids. In particular the regions of complete auxeticity enlarge.
On the role of electronic polarization in continuous structural transitions
Authors: Yang Xiaodong , Riseborough Peter S. , Smith J. L. , Shapiro S. M. , Lashley J. C.
Published: February 2010

Martensitic transitions are defined to be diffusionless structural transitions that lower the crystal symmetry and in which the order parameter, usually strain and shuffle, changes discontinuously. It had been proposed that martensitic transitions are driven by the entropy, due to the soft phonons. Anderson and Blount have shown that it is highly improbable that structural transitions are second‐order (continuous), and they have suggested that the apparently continuous structural transition in V3Si is a ferroelectric transition. Recently, a continuous structural martensitic transition has also been identified in crystalline AuZn by Lashley et al. Furthermore, pressure measurements on AuZn show that the martensitic temperature can be depressed and suggest the existence of a quantum critical point. The exact nature of the apparently continuous structural transitions is still being debated. However, measurements of magneto‐acoustic oscillations in the speed of sound of AuZn indicate that the phonon softening may be driven by the polarization of the conduction electrons. This has been confirmed by recent measurements on AuZn and V3Si in magnetic fields, which have shown that the transitions are intimately linked to the dielectric response, and are in accord with the predictions of Dieterich and Fulde for V3Si. The field dependence of the electronic polarization and its role in the transition is discussed.
Theoretical investigation of a CDDW Hamiltonian for YBa2Cu3O7−δ
Authors: Goswami Partha
Published: February 2010

We investigate a chiral d‐density wave (CDDW) mean field Hamiltonian in momentum space for the under‐doped YBa2Cu3O7−δ (YBCO). We consider the commensurate density wave order which doubles the unit cell of the real space lattice and show that the transition to CDDW state gives rise to the occurrence of jump discontinuities in the entropy density difference between the CDDW state and the normal metallic state at eight points (“Hot spots”) on the boundary of the reduced Brillouin zone. The chirality induced anomalous Nernst signal is shown to arise mainly from the points, close to these “Hot spots,” and located on the boundary of the hole pockets as reported by the previous workers. Finally, we discuss the possibility of quantum oscillations in the specific heat for the system under consideration in the presence of a changing magnetic field.
Magnetic Grüneisen ratio of the random transverse‐field Ising chain
Authors: Vojta Thomas , Hoyos José A.
Published: February 2010

The magnetic analog of the Grüneisen parameter, that is, the magnetocaloric effect, is a valuable tool for studying field‐tuned quantum phase transitions. We determine the magnetic Grüneisen parameter of the one‐dimensional random transverse‐field Ising model, focusing on its low‐temperature behavior at the exotic infinite‐randomness quantum critical point and in the associated quantum Griffiths phases. We present extensive numerical simulations showing that the magnetic Grüneisen parameter diverges logarithmically with decreasing temperature in the quantum Griffiths phase. It changes sign right at criticality. These results confirm a recent strong‐disorder renormalization group theory. We also compare our findings to the behavior of the clean transverse‐field Ising chain.
Observation of pseudogap in the normal state of superconducting Mo3Sb7
Authors: Tran V. H. , Batkova M. , Batko I. , Pribulová Z. , Bukowski Z.
Published: February 2010

Using electron tunneling spectroscopy, we investigated density of states of Mo3Sb7 in the temperature range 1.7–60 K. The differential conductance dI/dV vs. V curve at 4.2 K shows that an energy pseudogap of $2\Delta \sim 15(2){\rm meV}$ is formed in the density of states. In the superconducting state, the tunneling spectra exhibit the presence of a BCS‐type superconducting gap of $\Delta _{{\rm sc}} (0) \sim 0.24{\rm meV}$. Future investigations of the interplay between superconductivity and possible SDW ordering, and the anisotropic nature of the nesting of the Fermi surface in Mo3Sb7 are highly desired.

magnified image

Tunneling spectra of Mo3Sb7 measured in the normal state (a) and in the superconducting state (b).
Scanning tunneling microscopy studies on CeCoIn5 and CeIrIn5
Authors: Ernst S. , Wirth S. , Steglich F. , Fisk Z. , Sarrao J. L. , Thompson J. D.
Published: February 2010

High‐quality single crystals of the heavy fermion superconductors CeCoIn5 and CeIrIn5 have been studied by means of low‐temperature scanning tunneling microscopy. Methods were established to facilitate in situ sample cleaving. Spectroscopy in CeCoIn5 reveals a gap which persists to above Tc, possibly evidencing a precursor state to superconductivity. Atomically resolved topographs show a rearrangement of the atoms at the crystal surface. This modification at the surface might influence the surface properties as detected by tunneling spectroscopy.
Angular dependence of the upper critical field Bc2 for CeCu2Si2
Authors: Vieyra Hugo A. , Oeschler Niels , Jeevan Hirale S. , Geibel Christoph , Steglich Frank
Published: February 2010

The angular dependence of the upper critical field Bc2 for A/S‐type CeCu2Si2 samples is determined. Both, the anisotropies within and outside the basal plane are measured using an angle‐resolved resistivity technique, where an external magnetic field serves as a directional probe. Two high‐quality A/S‐type single crystals are studied (TN ∼ 0.8 K, Tc ∼ 0.6 K). For the case where the magnetic field rotates within the basal plane, small variations of ∼0.5% are observed and ascribed to sample misalignment. When the magnetic field rotates from the basal plane towards the [001] direction, a strong anisotropy of Bc2 (∼20%) is observed. By comparing the expected orbital‐ and Pauli‐limiting fields, the strong effect of Pauli paramagnetism is realized. The latter is taken into account when using the anisotropic mass model to study the field anisotropy. Deviations are observed from such a conventional model.
Non‐magnetic Kondo effect in M–As–Se (M = Zr, Hf, Th) phases
Authors: Cichorek Tomasz , Bochenek Lukasz , Henkie Zygmunt , Schmidt Marcus , Czulucki Andreas , Kniep Rudiger , Steglich Frank
Published: February 2010

Thermodynamic and transport properties of the tetragonal M–As–Se (M = Zr, Hf, Th) phases demonstrate that these materials are disordered metals with the electronic‐specific‐heat coefficient as small as, e.g., 0.3 mJ K−2 mol−1 for Th–As–Se. Remarkably, all the M–As–Se systems display a magnetic‐field‐independent AT1/2 term in the low‐temperature electrical resistivity. As observed for ZrAs1.595Se0.393, the magnitude of this extra term may vary by a factor of nearly 3 as well as the resistivity minimum is shifted from 10.8 to about 15.0 K, dispite virtually the same electron‐diffusion constant. On the other hand, a magnetic‐field (B ≤ 14 T) dependence of the electron transport in arsenide selenides is strongly material dependent: both the positive and negative sign of the magnetoresistivity being proportional to either B2 or B1/2 were found. These observations point to a non‐magnetic Kondo effect due to a random distribution of structural two‐level systems in the disordered As/Se sublattice.
On the concept of effective temperature in current carrying quantum critical states
Authors: Kirchner Stefan , Si Qimiao
Published: February 2010

Quantum criticality has attracted considerable attention both theoretically and experimentally as a way to describe part of the phase diagram of strongly correlated systems. A scale‐invariant fluctuation spectrum at a quantum critical point (QCP) implies the absence of any intrinsic scale. Any experimental probe may therefore create an out‐of‐equilibrium setting; the system would be in a non‐linear response regime, which violates the fluctuation–dissipation theorem (FDT). Here, we study this violation and related out‐of equilibrium phenomena in a single‐electron transistor (SET) with ferromagnetic leads, which can be tuned through a quantum phase transition. We review the breakdown of the FDT and study the universal behavior of the fluctuation–dissipation relation of various correlators in the quantum critical regime. In particular, we explore the concept of effective temperature as a means to extend the FDT into the non‐linear regime.
Effect of cooling field strength and ferromagnetic shell shape on exchange bias in nanoparticles with inverted ferromagnetic–antiferromagnetic core‐shell morphology
Authors: Hu Yong , Liu Yan , Du An
Published: February 2010

The dependence of exchange bias (EB) effects on cooling field strength and particle shape in nanoparticles with antiferromagnetic (AFM) interfacial coupling and inverted AFM core with a fixed radius and ferromagnetic (FM) shell with various thicknesses are investigated by using a modified Monte Carlo Metropolis method. It is found that with the increase of cooling field, field‐cooled exchange bias field (HE) fluctuates in the range of negative values initially, and then has an abrupt jump from the negative value to the positive value, finally levels off. However, HE decreases as the FM shell shape varies from No. 1 to No. 13 regardless of the strength of cooling field. Coercivity is affected by cooling fields and shapes indicating distinct behaviors. Because the AFM core is almost unaffected by shape and frozen completely during measuring hysteresis loops, the effect of ferromagnets on EB, negligible in most of other systems, is ambiguously manifested in such an unconventionally structural system. Moreover, the phenomena are interpreted well by presenting the snapshots of microscopic spin energy distributions, which make us observe directly and vividly the movement of domains and the competition of energies. This work will shed new light into the microscopic origin of peculiar magnetic properties of nanoparticles with special structures.