bluuebunny/crossref_metadata_2025_split huggingface dataset:
Extra Copper‐mediated Enhancement of the DNA Cleavage Activity Supported with Wild‐type Cu, Zn Superoxide Dismutase
Authors: ZHOU Ruo‐Yu , JIANG Wei , ZHANG Li‐Na , WANG Li , LIU Chang‐Lin 
Published: March 2008

AbstractIt is well known that the primary function of wild type Cu, Zn superoxide dismutase (holo SOD) is to catalyze the conversion of the superoxide anion to H2O2 and O2 as an antioxidant enzyme. However, the aberrant copper‐mediated oxidation chemistry in the enzyme (including its mutation forms) that damages nucleic acids, proteins including itself and cell membrane has attracted extensive attention in the past decade. The present study examined the hydrogen peroxide‐dependent DNA cleavage activity supported with the combinations between holo SOD and extra copper (holo SOD+nCu(II)). The results indicate that the presence of extra copper can enhance the DNA cleavage activity and a cooperative effect between holo SOD and the extra Cu(II) occurs in DNA cleavage. The relative activity and kinetic assay showed that the DNA cleavage activity of holo SOD+nCu(II) was enhanced upon addition of extra Cu(II). The favorable pH regions for the DNA cleavage were observed to be 3.6–5.6 and 9.0–10, suggesting the species responsible for the DNA cleavage are different in different pH regions. In addition, to obtain an insight into DNA cleavage pathways, the effect of free radical scavengers and inhibitors on the DNA cleavage activity was probed.
Direct Ab Initio Dynamics Study on the Reaction of CH3CHF2 (HFC‐152a) with the Cl Atom
Authors: Sun Hao , He Hongqing , Liu Jingyao , Li Zesheng , Pan Xiumei , Wang Rongshun 
Published: March 2008

AbstractA direct ab initio dynamics method is used to investigate the hydrogen‐abstraction reaction CH3CHF2+Cl. One transition state is located for α‐H abstraction, and two are identified for β‐H abstraction. The potential‐energy surface (PES) is obtained at the G3(MP2)//MP2/6‐311G(d, p) level. Furthermore, the rate constants of the three channels are evaluated by using canonical variational transition‐state theory (CVT) with small‐curvature tunneling (SCT) contributions over a wide temperature range of 200–2500 K. The dynamic calculations show that the reaction proceeds mainly by α‐H abstraction over the whole temperature range. The calculated rate constants and branching ratios are both in good agreement with the available experimental values.
Photofragmentation of 2‐Deoxy‐D‐Ribose Molecules in the Gas Phase
Authors: Vall‐llosera Gemma , Huels Michael A. , Coreno Marcello , Kivimäki Antti , Jakubowska Katarzyna , Stankiewicz Marek , Rachlew Elisabeth 
Published: March 2008

AbstractWe have measured the synchrotron‐induced photofragmentation of isolated 2‐deoxy‐D‐ribose molecules (C5H10O4) at four photon energies, namely, 23.0, 15.7, 14.6, and 13.8 eV. At all photon energies above the molecule′s ionization threshold we observe the formation of a large variety of molecular cation fragments, including CH3+, OH+, H3O+, C2H3+, C2H4+, CHxO+ (x=1,2,3), C2HxO+ (x=1–5), C3HxO+ (x=3–5), C2H4O2+, C3HxO2+ (x=1,2,4–6), C4H5O2+, C4HxO3+ (x=6,7), C5H7O3+, and C5H8O3+. The formation of these fragments shows a strong propensity of the DNA sugar to dissociate upon absorption of vacuum ultraviolet photons. The yields of particular fragments at various excitation photon energies in the range between 10 and 28 eV are also measured and their appearance thresholds determined. At all photon energies, the most intense relative yield is recorded for the m/q=57 fragment (C3H5O+), whereas a general intensity decrease is observed for all other fragments— relative to the m/q=57 fragment—with decreasing excitation energy. Thus, bond cleavage depends on the photon energy deposited in the molecule. All fragments up to m/q=75 are observed at all photon energies above their respective threshold values. Most notably, several fragmentation products, for example, CH3+, H3O+, C2H4+, CH3O+, and C2H5O+, involve significant bond rearrangements and nuclear motion during the dissociation time. Multibond fragmentation of the sugar moiety in the sugar–phosphate backbone of DNA results in complex strand lesions and, most likely, in subsequent reactions of the neutral or charged fragments with the surrounding DNA molecules.
Behavior of LiOH·H2O crystals obtained by evaporation and by drowning out
Authors: Graber T. A. , Morales J. W. , Robles P. A. , Galleguillos H. R. , Taboada M. E. 
Published: March 2008

AbstractIn the present work, the behavior of crystals derived from two different crystallization methods applied in a concentrated aqueous lithium salt solution was studied. The LiOH·H2O crystals obtained by a simple evaporation (Crystal I) differed in terms of morphology and solubility from those precipitated from lithium hydroxide solutions by addition of ethanol as a co‐solvent (Crystal II). Solubility of Crystal II at different temperatures (15 to 35°C) and mass ratios of ethanol to water (0 to 0.1) was determined. Polymorphic like behavior of these crystals was evidenced from X‐ray diffraction patterns. Measurement of density, refractive index, absolute viscosity and electrical conductivity of saturated solutions are reported. A thermodynamic analysis in terms of the Chen model for the calculation of activity coefficients, indicate that the polymorphic system in water and in water + ethanol (ethanol/water ratio 0.1) is enantiotropic. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis, crystal growth and properties of the charge transfer complex adduct of 2‐nitro aniline with picric acid – An organic non‐linear optical material
Authors: Bharathikannan R. , Chandramohan A. , Kandhaswamy M. A. , Chandrasekaran J. , Renganathan R. , Kandavelu V. 
Published: March 2008

AbstractThe organic NLO material 2‐nitro aniline and picric acid (2NAP) was synthesized, needle shaped single crystals of dimension 10 × 1 × 0.8 mm‐3 were grown by slow evaporation solution growth technique from the saturated solution of the title compound in chloroform at ambient temperature. The material was characterized through elemental analysis, powder XRD, 1H NMR, 13C NMR and FTIR techniques. The various planes of reflection have been identified from the XRD powder pattern. The formation of the charge transfer complex was confirmed by UV‐VIS spectroscopy. The thermal stability of the crystals was investigated using TG/DTA analyses techniques. The second harmonic generation (SHG) efficiency of the material was estimated using Nd: YAG laser as source. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis of rhombohedral strontium carbonate aggregates at the water/hexamethylene interface with cetyltrimethylammonium bromide
Authors: Chen Long , Shen Yuhua , Xie Anjian , Huang Fangzhi , Li Shikuo , Zhang Qingfeng 
Published: March 2008

AbstractUnusual rhombohedral strontium carbonate (SrCO3) aggregates have been synthesized in situ from strontium nitrate by the slow release of carbon dioxide by alkaline hydrolysis of diethyl carbonate at the water/hexamethylene interface in the presence of cetyltrimethylammonium bromide (CTAB). Transmission electron microscopy, Fourier transform infrared spectroscopy and X‐ray powder diffractometry were used to characterize the products. The results indicate that rhombohedral SrCO3 aggregates are obtained with weaker crystallinity and sizes of several micrometers. The possible formation mechanism of the SrCO3 aggregates at the interface is discussed, which can be interpreted by particle‐aggregation based non‐classical crystallization laws. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth and properties of Ba‐doped KDP crystals
Authors: Zheng Guozong , Su Genbo , Zhuang Xinxin , Lin Xiuqin , Li Zhengdong 
Published: March 2008

AbstractKDP crystals were rapidly grown from solution doped with different Ba2+ concentrations. The effects of Ba2+ on the growth rate, morphology and quality of KDP crystals were discussed. Significant changes in shapes and volume of the grown crystals have been observed. During the growth process, defect region expands gradually with the increasing Ba2+ concentration. Samples were cut from different parts of the as‐grown crystals for investigating the optical quality, including transmission spectrum, scattering centers. Through comparison, it is found that the nonuniform distribution of Ba2+ ions causes remarkable difference in optical quality between prismatic and pyramidal sectors. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bifunctional Metal‐Salen Complexes as Efficient Catalysts for the Fixation of CO2 with Epoxides under Solvent‐Free Conditions
Authors: Miao Cheng‐Xia , Wang Jin‐Quan , Wu Ying , Du Ya , He Liang‐Nian 
Published: March 2008

AbstractA bifunctional cobalt‐salen complex containing a Lewis acidic metal center and a quaternary phosphonium salt unit anchored on the ligand effectively catalyzes the synthesis of cyclic carbonates from CO2 and epoxides under mild conditions without the utilization of additional organic solvents or co‐catalysts. The effects of various reaction variables on the catalytic performance were studied in detail and indicate an optimized reaction temperature of about 100 °C and CO2 pressure of around 4 MPa, although the reaction proceeds smoothly even at pressures as low as 2 MPa. The catalyst is applicable to a variety of epoxides, producing the corresponding cyclic carbonates in good yields in most cases. Furthermore, the catalyst can be easily recovered and reused several times without significant loss of its catalytic activity. This process thus represents a greener pathway for the environmentally benign chemical fixation of CO2 to produce cyclic carbonates.
Analysis of Particle Pumping Using SOLDOR/NEUT2D Code in the JT‐60U Tokamak
Authors: Kawashima H. , Shimizu K. , Takizuka T. 
Published: March 2008

AbstractIn order to understand the particle pumping on JT‐60U, we analyze the roles of atomic and molecular processes using SOLDOR/NEUT2D code. A case of short strike point distance shows that most of neutrals produced on the targets go toward the exhaust slot directly. Whereas, neutrals are scattered in the spherically at random for the long distance case by collision processes and a few of them go toward the slot. It is clarified that the incident neutrals to the slot at low ne /high Te divertor plasma condition are dominated by atoms. Those at high ne /low Te condition are dominated by molecules due to elastic collision. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Zebrafish sip1a and sip1b are essential for normal axial and neural patterning
Authors: Delalande Jean‐Marie , Guyote Meaghann E. , Smith Chelsey M. , Shepherd Iain T. 
Published: March 2008

AbstractSmad‐interacting protein‐1 (SIP1) has been implicated in the development of Mowat‐Wilson syndrome whose patients exhibit Hirschsprung disease, an aganglionosis of the large intestine, as well as other phenotypes. We have identified and cloned two sip1 orthologues in zebrafish. Both sip1 orthologues are expressed maternally and have dynamic zygotic expression patterns that are temporally and spatially distinct. We have investigated the function of both orthologues using translation and splice‐blocking morpholino antisense oligonucleotides. Knockdown of the orthologues causes axial and neural patterning defects consistent with the previously described function of SIP1 as an inhibitor of BMP signaling. In addition, knockdown of both genes leads to a significant reduction/loss of the post‐otic cranial neural crest. This results in a subsequent absence of neural crest precursors in the posterior pharyngeal arches and a loss of enteric precursors in the intestine. Developmental Dynamics 237:1060–1069, 2008. © 2008 Wiley‐Liss, Inc.
psoriasis regulates epidermal development in zebrafish
Authors: Webb Ashley E. , Driever Wolfgang , Kimelman David 
Published: March 2008

AbstractThe zebrafish epidermis completely envelopes the embryo by 14 hours postfertilization, providing an essential barrier between the internal organs and the environment. As the embryo increases in size, keratinocytes in the epidermis must proliferate and differentiate to form the three epidermal layers present in the adult. The mechanisms controlling growth, differentiation, and maintenance of the fish epidermis are mostly unknown. Here, we describe psoriasis, an epidermal mutant that exhibits widespread overproliferation of the epidermis at 3 days postfertilization and a defect in keratinocyte differentiation. Based on mosaic analysis, we show that psoriasis acts non–cell‐autonomously, suggesting that psoriasis encodes a secreted factor. Our analysis of the psoriasis mutant indicates that keratinocyte differentiation and proliferation are tightly regulated to maintain a cohesive epidermal sheet around the embryo and that disruptions in these processes result in the formation of epidermal aggregates. Developmental Dynamics 237:1153–1164, 2008. © 2008 Wiley‐Liss, Inc.
BetaA, the major beta globin in definitive red blood cells, is present from the onset of primitive erythropoiesis in chicken
Authors: Alev Cantas , McIntyre Brendan A.S. , Nagai Hiroki , Shin Masahiro , Shinmyozu Kaori , Jakt Lars M. , Sheng Guojun 
Published: March 2008

AbstractReflecting physiological changes in oxygen acquisition and regulatory changes in globin transcription, the makeup of globin chains in erythrocytes varies in development and disease. The relationship between the globin chain composition and erythropoietic lineages/niches is not well‐understood. Using a combination of proteomic‐, genomic‐, and intron‐based in situ hybridization analyses, we show that the transcripts and protein product of the major adult beta globin, betaA, are present as early as the major embryonic beta globins during chicken primitive erythropoiesis. A rapid rise in betaA percentage is seen from embryonic day (E) 5, reaching adult profile by E7. Our data suggest that betaA locus is active from the onset of primitive erythropoiesis and that beta globin switching during development may reflect a change in relative transcript abundance rather than a strict on/off switch in gene activation. Developmental Dynamics 237:1193–1197, 2008. © 2008 Wiley‐Liss, Inc.
Dendritic cell expression of the Notch ligand jagged2 is not essential for Th2 response induction in vivo
Authors: Worsley Alan G. F. , LeibundGut‐Landmann Salome , Slack Emma , Phng Li‐Kun , Gerhardt Holger , Sousa Caetano Reis e , MacDonald Andrew S. 
Published: March 2008

AbstractWe have addressed the hypothesis that Notch ligands play a decisive role in determining the ability of antigen‐presenting cells to influence T cell polarization. Dendritic cells displayed distinct expression profiles of Delta and Jagged ligands for Notch when exposed to biologically relevant pathogen preparations associated with Th1 or Th2 responses. Expression of delta4 was increased, and jagged2 decreased, after dendritic cell exposure to the Th1‐promoting bacterium Propionibacterium acnes. In contrast, soluble egg antigen (SEA) from the parasitic helminth Schistosoma mansoni, a potent Th2 inducer, failed to significantly alter dendritic cell expression of any of the Notch ligands measured. Irrespective of this, jagged2‐deficient dendritic cells were severely impaired in their ability to instruct Th2 polarization of naive T cells in vitro. However, the ability of SEA‐pulsed jagged2‐deficient dendritic cells to induce a Th2 response in vivo was unimpaired relative to jagged2‐sufficient dendritic cells. Further, jagged2‐deficient dendritic cells activated by P. acnes exhibited no evidence of enhanced (or impaired) Th1 induction in vivo. These data suggest that, although involved in Th2 direction in vitro, jagged2 is not fundamentally required for Th2 induction by SEA‐activated dendritic cells in vivo.
Sequential phases in the development of Aire‐expressing medullary thymic epithelial cells involve distinct cellular input
Authors: White Andrea J. , Withers David R. , Parnell Sonia M. , Scott Hamish S. , Finke Daniela , Lane Peter J. L. , Jenkinson Eric J. , Anderson Graham 
Published: March 2008

AbstractIntrathymic deletion of immature thymocytes that express self‐reactive TCR specificities is essential in the generation of self tolerance. Medullary thymic epithelial cells (mTEC) expressing the transcriptional regulator Aire play a key role in this process by regulating expression of tissue‐restricted antigens to ensure tolerance to peripheral tissues. Here, we have analysed the cellular and molecular requirements for the initial appearance of Aire+ mTEC in the embryonic thymus, in addition to their persistence in the adult thymus. Analysis of thymic ontogeny shows that the emergence of embryonic Aire+ mTEC occurs prior to the appearance of mature thymocytes, and depends upon lymphoid tissue inducer cells expressing retinoic acid receptor‐related orphan receptor γ. In the adult thymus, we show that Aire+ mTEC develop in the absence of thymocyte positive and negative selection and CD40 signalling, but are present at reduced frequency. Collectively these data support a model where the initial differentiation of Aire+ mTEC involves receptor activator of NF‐κB (RANK)‐RANKL interactions with lymphoid tissue inducer cells, with subsequent mTEC turnover and/or survival involving CD40‐mediated signalling following interactions with mature CD4+ thymocytes that express CD40L.
United we win, divided we fail? Effects of cognitive merger representations and performance feedback on merging groups
Authors: Giessner Steffen R. , Mummendey Amélie 
Published: March 2008

AbstractResearch has shown that cognitive representations of mergers influence intergroup evaluations. This paper extends this research by studying how cognitive representations of mergers (one group, dual identity, and two groups) interact with performance feedback (success and failure) to affect intergroup evaluations. Two competing hypotheses were tested, which made different predictions in case of superordinate group salience combined with subgroup salience after merger failure: The subgroup‐salience‐hypothesis predicts that subgroup salience during a merger generally results in pre‐merger ingroup bias toward the pre‐merger outgroup (i.e., two groups and dual identity). The superordinate‐ salience‐hypothesis predicts that subgroup salience only results in pre‐merger ingroup bias if superordinate group salience is low (i.e., two groups). Both hypotheses predict low levels of ingroup bias after merger success. Study 1 confirmed the second hypothesis using a 3 (merger representation: one group, dual identity, and two groups) × 2 (merger feedback: failure and success) design with interacting groups. Study 2 replicated the results in an adapted minimal group paradigm. Copyright © 2007 John Wiley & Sons, Ltd.
Detection of carbonyl‐modified proteins in interfibrillar rat mitochondria using N′‐aminooxymethylcarbonylhydrazino‐D‐biotin as an aldehyde/keto‐reactive probe in combination with Western blot analysis and tandem mass spectrometry
Authors: Chung Woon‐Gye , Miranda Cristobal L. , Maier Claudia S. 
Published: March 2008

AbstractThere is now a large body of supporting data available that links oxidative modifications of proteins to a large number of diseases, degenerative disorders and aging. However, the detailed analysis of oxidative protein modifications remains challenging. Here, we report a new efficient method for identification of oxidatively modified proteins in complex biological samples which is based on the use of an aldehyde‐reactive probe, N′‐aminooxymethylcarbonylhydrazino‐D‐biotin (ARP), in combination with Western‐type analyses and MS. The biotinylated hydroxylamine derivative forms a chemically stable oxime derivative with the aldehyde/keto group found in carbonyl‐modified proteins. The biotin tag is detected by avidin affinity staining. ARP‐positive proteins are subsequently subjected to in‐gel trypsinization and MS/MS for protein identification. We demonstrate the usefulness of the method for the analysis of protein extracts obtained from interfibrillar heart mitochondria (IFM) from young and old rats. In this study, we identified as putative major protein targets of oxidative modifications the mitochondrial matrix protein, aconitase, the inner mitochondrial membrane protein, ADP/ATP translocase, and constituents of the electron transport chain complexes IV and V. An age‐related increase of carbonyl levels was found for aconitase and ATP synthase.
Numerical experiments with several variant WENO schemes for the Euler equations
Authors: Hsieh Tsang‐Jen , Wang Ching‐Hua , Yang Jaw‐Yen 
Published: March 2008

AbstractNumerical experiments with several variants of the original weighted essentially non‐oscillatory (WENO) schemes (J. Comput. Phys. 1996; 126:202–228) including anti‐diffusive flux corrections, the mapped WENO scheme, and modified smoothness indicator are tested for the Euler equations. The TVD Runge–Kutta explicit time‐integrating scheme is adopted for unsteady flow computations and lower–upper symmetric‐Gauss–Seidel (LU‐SGS) implicit method is employed for the computation of steady‐state solutions. A numerical flux of the variant WENO scheme in flux limiter form is presented, which consists of first‐order and high‐order fluxes and allows for a more flexible choice of low‐order schemes. Computations of unsteady oblique shock wave diffraction over a wedge and steady transonic flows over NACA 0012 and RAE 2822 airfoils are presented to test and compare the methods. Various aspects of the variant WENO methods including contact discontinuity sharpening and steady‐state convergence rate are examined. By using the WENO scheme with anti‐diffusive flux corrections, the present solutions indicate that good convergence rate can be achieved and high‐order accuracy is maintained and contact discontinuities are sharpened markedly as compared with the original WENO schemes on the same meshes. Copyright © 2008 John Wiley & Sons, Ltd.
Forecasting volatility with noisy jumps: an application to the Dow Jones Industrial Average stocks
Authors: Awartani Basel M. A. 
Published: March 2008

AbstractEmpirical high‐frequency data can be used to separate the continuous and the jump components of realized volatility. This may improve on the accuracy of out‐of‐sample realized volatility forecasts. A further improvement may be realized by disentangling the two components using a sampling frequency at which the market microstructure effect is negligible, and this is the objective of the paper. In particular, a significant improvement in the accuracy of volatility forecasts is obtained by deriving the jump information from time intervals at which the noise effect is weak. Copyright © 2008 John Wiley & Sons, Ltd.
Optimised Mixture Formation for Diesel Fuel Processing
Authors: Porš Z. , Pasel J. , Tschauder A. , Dahl R. , Peters R. , Stolten D. 
Published: March 2008

AbstractMixture formation plays an important role in the diesel reforming process. It is important to maintain proper O2/C and H2O/C ratios to avoid hot spots and coking. Fuel must be completely evaporated before entering the reaction zone in order to prevent catalyst damage by coking.Computational fluid dynamics (CFD) is used to optimise the mixing process. Turbulent mixing, diesel spray injections and evaporation and simplified chemical reactions have been calculated. This revealed critical parts of the existing construction. However, experimental verification is necessary.To identify thermodynamic conditions for a possible carbon formation process, experiments with idealised model fuels as well as with real diesel fuel were carried out.Flow visualisation experiments serve for the verification of the CFD simulations. Quartz glass reactors as models of the reformers were operated under real mixing temperatures (400 °C) to observe the effect of the flow profile on fuel sprays. Experiments with coloured fuels were used to visualise the flow and concentration profiles in the mixing chamber. Results were compared with CFD models.Two patented reformers were designed as a result of the CFD optimisation. These were operated for 500 h and 1,000 h respectively with a commercially available diesel, showing very promising results.