bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inhibitory control during smooth pursuit in Parkinson's disease and Huntington's disease
Authors: Henderson Tracy , Georgiou‐Karistianis Nellie , White Owen , Millist Lynette , Williams David R. , Churchyard Andrew , Fielding Joanne 
Published: May 2011

AbstractThe basal ganglia are involved in the preferential selection and suppression of competing responses. Parkinson's disease and Huntington's disease are 2 prototypical basal ganglia disorders that feature impaired inhibitory control, a function of poor conflict resolution. Previous saccadic studies showed that individuals with Parkinson's disease experience difficulty suppressing unwanted ocular motor responses, whereas evidence for a similar difficulty in Huntington's disease is more equivocal. Relative to saccades, few research studies have examined inhibitory control processes in the context of an ongoing smooth pursuit task. In this study, we examined the ability of 16 patients with Parkinson's disease and 12 patients with Huntington's disease to suppress automatic responses to irrelevant distracters that transiently appeared during the tracking of a moving visual stimulus. Compared with an equivalent number of age‐matched controls, patients with Parkinson's disease generated proportionately more saccades to distracter stimuli. This was particularly evident for distracters appearing far away from the target. Conversely, whereas individuals with early‐stage Huntington's disease and healthy controls made a comparable number of errors toward distracter stimuli, those in a more advanced clinical stage demonstrated significantly poorer inhibitory control. The current findings in parkinsonian patients replicate those previously reported in the saccadic and manual response literature, demonstrating difficulty inhibiting a competing motor response. However, in Huntington's disease we demonstrate for the first time that inhibitory control declines in more advanced‐disease stages. This suggests that ocular motility may provide a sensitive marker of clinical disease progression in Huntington's disease. © 2011 Movement Disorder Society
T2‐weighted MRI of post‐infarct myocardial edema in mice
Authors: Beyers Ronald J. , Smith R. Scott , Xu Yaqin , Piras Bryan A. , Salerno Michael , Berr Stuart S. , Meyer Craig H. , Kramer Christopher M. , French Brent A. , Epstein Frederick H. 
Published: May 2011

AbstractT2‐weighted, cardiac magnetic resonance imaging (T2w CMR) can be used to noninvasively detect and quantify the edematous region that corresponds to the area at risk (AAR) following myocardial infarction (MI). Previously, CMR has been used to examine structure and function in mice, expediting the study of genetic manipulations. To date, CMR has not been applied to imaging of post‐MI AAR in mice. We developed a whole‐heart, T2w CMR sequence to quantify the AAR in mouse models of ischemia and infarction. The ΔB0 and ΔB1 environment around the mouse heart at 7 T were measured, and a T2‐preparation sequence suitable for these conditions was developed. Both in vivo T2w and late gadolinium enhanced CMR were performed in mice after 20‐min coronary occlusions, resulting in measurements of AAR size of 32.5 ± 3.1 (mean ± SEM)% left ventricular mass, and MI size of 50.1 ± 6.4% AAR size. Excellent interobserver agreement and agreement with histology were also found. This T2w imaging method for mice may allow for future investigations of genetic manipulations and novel therapies affecting the AAR and salvaged myocardium following reperfused MI. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Closed circuit MR compatible pulsatile pump system using a ventricular assist device and pressure control unit
Authors: Lorenz R. , Benk C. , Bock J. , Stalder A.F. , Korvink J.G. , Hennig J. , Markl M. 
Published: May 2011

AbstractThe aim of this study was to evaluate the performance of a closed circuit MR compatible pneumatically driven pump system using a ventricular assist device as pulsatile flow pump for in vitro 3D flow simulation. Additionally, a pressure control unit was integrated into the flow circuit. The performance of the pump system and its test‐retest reliability was evaluated using a stenosis phantom (60% lumen narrowing). Bland–Altman analysis revealed a good test–retest reliability (mean differences = −0.016 m/s, limits of agreement = ±0.047 m/s) for in vitro flow measurements. Furthermore, a rapid prototyping in vitro model of a normal thoracic aorta was integrated into the flow circuit for a direct comparison of flow characteristics with in vivo data in the same subject. The pneumatically driven ventricular assist device was attached to the ascending aorta of the in vitro model to simulate the beating left ventricle. In the descending part of the healthy aorta a flexible stenosis was integrated to model an aortic coarctation. In vivo and in vitro comparison showed significant (P = 0.002) correlations (r = 0.9) of mean velocities. The simulation of increasing coarctation grade led to expected changes in the flow patterns such as jet flow in the post‐stenotic region and increased velocities. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Characterisation of rock aggregate breakage properties using realistic texture‐based modelling
Authors: Liu Hongyuan , Lindqvist Per‐Arne , Åkesson Urban , Kou Shaoquan , Lindqvist Jan‐Eric 
Published: May 2011

SUMMARYRealistic texture‐based modelling methods, that is microstructural modelling and micromechanical modelling, are developed to simulate the rock aggregate breakage properties on the basis of the rock actual microstructure obtained using microscopic observations and image analysis. The breakage properties of three types of rocks, that is Avja, LEP and Vandle taken from three quarries in Sweden, in single aggregate breakage tests and in inter‐aggregate breakage tests are then modelled using the proposed methods. The microstructural modelling directly integrates the microscopic observation, image analysis and numerical simulation together and provides a valuable tool to investigate the mechanical properties of rock aggregates on the basis of their microstructure properties. The micromechanical modelling takes the most important microstructure properties of rock aggregates into consideration and can model the major mechanical properties. Throughout this study, it is concluded that in general, the microstructure properties of rock aggregate work together to affect their mechanical properties, and it is difficult to correlate a single microstructure property with the mechanical properties of rock aggregates. In particular, for the three types of rock Avja, LEP and Vandle in this study, crack size distribution, grain size and grain perimeter (i.e. grain shape and spatial arrangement) show good correlations with the mechanical properties. The crack length and the grain size negatively affect the mechanical properties of Avja, LEP and Vandle, but the perimeter positively influences the mechanical properties. Besides, the modelled rock aggregate breakage properties in both single aggregate and inter‐aggregate tests reveal that the aggregate microstructure, aggregate shape and loading conditions influence the breakage process of rock aggregate in service. For the rock aggregate with the same microstructure, the quadratic shape and good packing dramatically improve its mechanical properties. During services, the aggregate is easiest to be fragmented under point‐to‐point loading condition, and then in the sequence of multiple‐point, point‐to‐plane and plane‐to‐plane loading conditions. Copyright © 2011 John Wiley & Sons, Ltd.
Loss of epithelial oestrogen receptor α inhibits oestrogen‐stimulated prostate proliferation and squamous metaplasia via in vivo tissue selective knockout models
Authors: Chen Ming , Yeh Chiuan‐Ren , Chang Hong‐Chiang , Vitkus Spencer , Wen Xing‐Qiao , Bhowmick Neil A. , Wolfe Andrew , Yeh Shuyuan 
Published: June 2011

AbstractSquamous metaplasia (SQM) is a specific phenotype in response to oestrogen in the prostate and oestrogen receptor (ER) α is required to mediate this response. Previous studies utilizing tissue recombination with seminal vesicle (SV) mesenchyme and prostatic ductal tips from wild type and ERαKO mice suggested that both epithelial and stromal ERα are necessary for SQM. However, tissue recombination is conducted in the renal capsule of immune‐deficient mice, in which the microenvironment is different from normal prostate microenvironment in the intact mice. Furthermore, whether the requirement of stromal ERα in the SV for developing SQM is the same as in the prostate is unknown. Therefore, there is a clear need to evaluate the respective roles of ERα in prostate epithelial versus stromal compartments in the intact mouse. Here we generated a mouse model that has selectively lost ERα in either stromal (FSP‐ERαKO) or epithelial prostate cells (pes‐ERαKO) to determine the requirements of ERα for oestrogen‐stimulated prostate proliferation and SQM. Our results indicated that FSP‐ERαKO prostates develop full and uniform SQM, which suggests that loss of the majority (∼65%) of stromal ERα will not influence oestrogen‐mediated SQM. In contrast, loss of epithelial ERα inhibits oestrogen‐mediated prostate growth and SQM evidenced by decreasing cytokertin 10 positive squamous cell stratification and differentiation, by reduced ERα protein expression in SQM compared to wild type mice ERα, and by the presence of normal proliferative activities in the oestrogen‐treated pes‐ERαKO prostates. These in vivo results suggest that epithelial ERα is required for oestrogen‐mediated proliferative response and could be an appropriate target for preventing aberrant oestrogen signalling in the prostate. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Effect of confinement on power‐law fluid flow past a circular cylinder
Authors: Rao M.K. , Sahu Akhilesh K. , Chhabra R.P. 
Published: May 2011

AbstractThe role of confinement on the flow of power‐law fluids past a cylinder confined symmetrically between two parallel walls has been investigated numerically over wide ranges of conditions as follows: power‐law index (0.4 ≤n≤ 1.8), Reynolds number (40 ≤Re≤ 140) and blockage ratio (2,4,6). For Newtonian fluids, moderate degree of confinement stabilizes the flow thereby delaying the onset of the laminar vortex shedding regime. Although similar stabilization also occurs in shear‐thickening fluids, this relationship is complex for shear‐thinning fluids. Depending upon the degree of shear‐thinning, the walls may stabilize or destabilize the flow. Extensive results are presented on streamline, vorticity contours and pressure profiles herein. The power‐law behavior exerts significant influence on the macroscopic momentum transfer characteristics also. Thus, the drag and lift coefficients and Strouhal number exhibit complex dependence on Reynolds number, blockage ratio and power‐law index. Finally, the present results are consistent with the limited data available in the literature. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Putative copper‐ and zinc‐binding motifs in Streptococcus pneumoniae identified by immobilized metal affinity chromatography and mass spectrometry
Authors: Sun Xuesong , Xiao Chuan‐le , Ge Ruiguang , Yin Xingfeng , Li Hui , Li Nan , Yang Xiaoyan , Zhu Ying , He Xiang , He Qing‐Yu 
Published: May 2011

AbstractThe aim of metalloproteomics is to identify and characterize putative metal‐binding proteins and metal‐binding motifs. In this study, we performed a systematical metalloproteomic analysis on Streptococcus pneumoniae through the combined use of efficient immobilized metal affinity chromatography enrichment and high‐accuracy linear ion trap‐Orbitrap MS to identify metal‐binding proteins and metal‐binding peptides. In total, 232 and 166 putative metal‐binding proteins were respectively isolated by Cu‐ and Zn‐immobilized metal affinity chromatography columns, in which 133 proteins were present in both preparations. The putative metalloproteins are mainly involved in protein, nucleotide and carbon metabolisms, oxidation and cell cycle regulation. Based on the sequence of the putative Cu‐ and Zn‐binding peptides, putative Cu‐binding motifs were identified: H(X)mH (m=0–11), C(X)2C, C(X)nH (n=2–4, 6, 9), H(X)iM (i=0–10) and M(X)tM (t=8 or 12), while putative Zn‐binding motifs were identified as follows: H(X)mH (m=1–12), H(X)iM (i=0–12), M(X)tM (t=0, 3 and 4), C(X)nH (n=1, 2, 7, 10 and 11). Equilibrium dialysis and inductively coupled plasma‐MS experiments confirmed that the artificially synthesized peptides harboring differential identified metal‐binding motifs interacted directly with the metal ions. The metalloproteomic study presented here suggests that the comparably large size and diverse functions of the S. pneumoniae metalloproteome may play important roles in various biological processes and thus contribute to the bacterial pathologies.
Water soluble poly(histamine acrylamide) with superior buffer capacity mediates efficient and nontoxic in vitro gene transfection
Authors: Luo Sibin , Cheng Ru , Meng Fenghua , Park Tae Gwan , Zhong Zhiyuan 
Published: May 2011

AbstractWater‐soluble cationic polymers, poly(histamine acrylamide)s (PHAs), with superior buffer capacity at the endosomal pH range were designed, prepared, and investigated for non‐viral gene transfection. PHAs were obtained with molecular weights ranging from 9.2 to 28.7 kDa through controlled radical polymerization of histamine acrylamide (HA). Acid–base titration results displayed that all PHA polymers had a remarkably high buffer capacity of about 70% at pH 5.1–7.2. 12.7–28.7 kDa PHAs were able to effectively condense DNA into nano‐sized (<220 nm) polyplexes with moderate positive surface charges (+13–+19 mV) at N/P ratios ≥10/1. CCK assays indicated that polyplexes of 12.7 and 17.5 kDa PHAs were non‐toxic to COS‐7 cells up to a tested N/P ratio of 20/1. Interestingly, the in vitro transfection using pCMV‐Luc and pEGFP‐C1 plasmid DNA as reporter genes showed that polyplexes of 12.7 kDa PHA formed at an N/P ratio of 20/1 mediated efficient transfection in COS‐7 cells under 10% serum conditions, with transfection efficiencies comparable to that of 25 kDa polyethylenimine control. Their versatile design of structures, controlled synthesis, low cytotoxicity, and high transfection activity render PHA‐based cationic polymers particularly interesting for the development of safe and efficient non‐viral gene delivery systems. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.
Preparation, Characterization, and Catalytic Activity of Nanosized NiO and ZnO: Part 74
Authors: Kumar Dinesh , Kapoor Inder P. S. , Singh Gurdip , Siril Prem Felix , Tripathi Alok Mani 
Published: June 2011

AbstractNanocrystals of NiO and ZnO were prepared by a novel refluxing method and characterized by XRD and TEM. The average particles size of NiO and ZnO were found to be 6 and 31 nm, respectively, from the XRD patterns. These Transition Metal Oxide Nanocrystals (TMONs) were found to catalyze the thermal decomposition of 5‐nitro‐1, 2, 4‐triazol‐3‐one (NTO). Between the two TMOs, ZnO was found to have better catalytic activity than NiO. Kinetic parameters for the isothermal decomposition of NTO in presence and absence of these metal oxides were obtained using a model‐free isoconversional method. The activation energy for NTO, NTO+1 %NiO, and NTO+1 %ZnO was found to be 60.1, 52.1, and 47.9 kJ mol−1 and a similar order was found from the explosion studies (36.1, 31.6, and 27.4 kJ mol−1, respectively).
Crystal structure and enzymatic characterization of thymidylate synthase X from Helicobacter pylori strain SS1
Authors: Wang Kuifeng , Wang Qi , Chen Jing , Chen Lili , Jiang Hualiang , Shen Xu 
Published: June 2011

AbstractThymidylate synthase X (ThyX) catalyzes the methylation of dUMP to form dTMP in bacterial life cycle and is regarded as a promising target for antibiotics discovery. Helicobacter pylori is a human pathogen associated with a number of human diseases. Here, we cloned and purified the ThyX enzyme from H. pylori SS1 strain (HpThyX). The recombinant HpThyX was discovered to exhibit the maximum activity at pH 8.5, and Km values of the two substrates dUMP and CH2H4folate were determined to be 15.3 ± 1.25 μM and 0.35 ± 0.18 mM, respectively. The analyzed crystal structure of HpThyX with the cofactor FAD and the substrate dUMP (at 2.31 Å) revealed that the enzyme was a tetramer bound to four dUMP and four FAD molecules. Different from the catalytic feature of the classical thymidylate synthase (ThyA), N5 atom of the FAD functioned as a nucleophile in the catalytic reaction instead of Ser84 and Ser85 residues. Our current work is expected to help better understand the structural and enzymatic features of HpThyX thus further providing valuable information for anti‐H. pylori inhibitor discovery.
Serum prosaposin levels are increased in patients with advanced prostate cancer
Authors: Koochekpour Shahriar , Hu Siyi , Vellasco‐Gonzalez Cruz , Bernardo Ruiz , Azabdaftari Gissu , Zhu Guodong , Zhau Haiyen E. , Chung Leland W.K. , Vessella Robert L. 
Published: May 2011

AbstractBACKGROUNDWe previously cloned prosaposin (PSAP) from metastatic castrate‐resistant prostate cancer (mCRPCa) cells and demonstrated its genomic amplification and/or overexpression in metastatic PCa cell lines, xenografts, and lymph node metastases. The clinicohistopathological significance of serum PSAP levels and its tissue expression and association with predictive or prognostic variable in primary or advanced PCa are not known.METHODSWe examined PSAP expression by immunohistochemical staining during early embryogenic development of the prostate and within a large tissue microarray which included 266 benign and malignant prostate tissues. In addition, serum PSAP levels in the age‐adjusted normal male population and in 154 normal individuals and patients with primary or mCRPCa were measured by an ELISA assay.RESULTSUnivariate and multivariate analyses revealed a significant and inverse association between PSAP expression and clinical stages II and III tumors, dominant Gleason patterns 3 and 4, and seminal vesicle invasion. In the normal male population, the lowest serum PSAP level was detected before puberty, peaked at the most reproductive age group (20‐ to 39‐year old), and then, decreased to a range between the two groups for men above 40‐year old. Regardless of age and when compared with normal individuals, serum PSAP levels significantly decreased in primary organ‐confined PCa, but increased in those with mCRPCa.CONCLUSIONOur results show that PSAP has the potential to differentiate between primary and advanced PCa. Additional large‐scale studies are needed to define the usefulness of tissue expression or serum PSAP levels as a diagnostic or prognostic marker or as a therapeutic target in PCa. Prostate 72:253–269, 2012. © 2011 Wiley Periodicals, Inc.
Characterization of dislocation arrays in AlN single crystals grown by PVT
Authors: Dalmau Rafael , Moody Baxter , Xie Jinqiao , Collazo Ramón , Sitar Zlatko 
Published: May 2011

AbstractThe density and distribution of extended defects in AlN single crystals grown by physical vapor transport (PVT) was studied by bright field and polarized light microscopy, defect‐selective etching, and high resolution X‐ray diffraction (HRXRD). Etch pits associated with dislocation arrays forming low angle grain boundaries (LAGB) were observed and two types of LAGB were identified. Reduction of LAGB in AlN grown under reduced radial temperature gradients, as estimated by simulation of the growth cell, was demonstrated.
Towards experimental identification of vacancy complexes in InN
Authors: Rauch Christian , Makkonen Ilja , Tuomisto Filip 
Published: June 2011

AbstractIn this contribution we present ab initio calculations of positron states and annihilation at vacancies and vacancy complexes in InN. Momentum distributions of annihilating electron–positron pairs in indium (VIn) and nitrogen vacancies (VN) as well as mixed vacancy clusters are calculated. Based on the modelled data the possibility of their experimental detection and distinction using positron annihilation spectroscopy is discussed. No localization of the positron density is found for isolated VN and VN clusters of up to 4VN. On the other hand, VIn and mixed vacancy clusters act as efficient positron traps in InN. While the calculated momentum distributions for the divacancy and VIn are quite close, mixed vacancy clusters which contain one VIn and two or more VN show well distinct spectra, that could be distinguished in suitable positron annihilation experiments.
Pressure induced phase transitions in transition metal nitrides: Ab initio study
Authors: Srivastava Anurag , Chauhan Mamta , Singh R. K. 
Published: June 2011

AbstractWe have analyzed the stability of transition metal nitrides (TMNs) XN (X = Ti, Zr, Hf, V, Nb, Ta) in their original rocksalt (B1) and hypothetical CsCl (B2) type phases under high compression. The ground state total energy calculation approach of the system has been used through the generalized gradient approximation (GGA) with the Perdew‐Burke‐Ernzerhof (PBE) type parameterization as exchange correlation functional. In the whole series of nitrides taken into consideration, tantalum nitride is found to be the most stable. We have observed that under compression the original B1‐type phase of these nitrides transforms to a B2‐type phase. We have also discussed the computation of ground state properties, like the lattice constant (a), bulk modulus (B0) and first order pressure derivative of the bulk modulus (B'0) of the TMNs and their host elements.
An optical and dielectric spectroscopy study of Er3+‐doped KTaO3
Authors: Trepakov Vladimir , Skvortsov Alexander , Poletaev Nikolai , Potůček Zdeněk , Nuzhnyy Dmitry , Jastrabik Lubomír , Dejneka Alexandr 
Published: June 2011

AbstractWe report the results of a multifaceted study of optical and dielectric properties of erbium‐doped (500 ppm) potassium tantalate incipient ferroelectric single crystals. Studies of optical absorption and photoluminescence spectra allowed us to determine the system of energy levels that control the main internal optical transitions in the 4f electronic shell of Er3+ in KTaO3. It was found that at least two types of Er3+ centres, major and minor ones, are present. The major centres are non‐cubic, formed by Er3+ substituting for K+ sites; these are responsible for the n‐type conductivity of KTaO3:Er crystals. Wideband optical absorption with a maximum at 1.13 eV (λ = 1097 nm) was observed in the near‐IR range and was attributed to polaron formation. Low‐temperature far‐infrared reflectivity studies revealed an increase in the frequency of the lowest transverse optical mode and a decrease in the dielectric permittivity in comparison with undoped KTaO3 crystals. This stiffening means the suppression of the ferroelectric instability in the system.