bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Family of Ferrocene‐Stabilized Silylium Ions: Synthesis, 29Si NMR Characterization, Lewis Acidity, Substituent Scrambling, and Quantum‐Chemical Analyses
Authors: Müther Kristine , Hrobárik Peter , Hrobáriková Veronika , Kaupp Martin , Oestreich Martin 
Published: October 2013

AbstractThe purpose of this systematic experimental and theoretical study is to deeply understand the unique bonding situation in ferrocene‐stabilized silylium ions as a function of the substituents at the silicon atom and to learn about the structure parameters that determine the 29Si NMR chemical shift and electrophilicity of these strong Lewis acids. For this, ten new members of the family of ferrocene‐stabilized silicon cations were prepared by a hydride abstraction reaction from silanes with the trityl cation and characterized by multinuclear 1H and 29Si NMR spectroscopy. A closer look at the NMR spectra revealed that additional minor sets of signals were not impurities but silylium ions with substitution patterns different from that of the initially formed cation. Careful assignment of these signals furnished experimental proof that sterically less hindered silylium ions are capable of exchanging substituents with unreacted silane precursors. Density functional theory calculations provided mechanistic insight into that substituent transfer in which the migrating group is exchanged between two silicon fragments in a concerted process involving a ferrocene‐bridged intermediate. Moreover, the quantum‐chemical analysis of the 29Si NMR chemical shifts revealed a linear relationship between δ(29Si) values and the Fe⋅⋅⋅Si distance for subsets of silicon cations. An electron localization function and electron localizability indicator analysis shows a three‐center two‐electron bonding attractor between the iron, silicon, and C′ipso atoms, clearly distinguishing the silicon cations from the corresponding carbenium ions and boranes. Correlations between 29Si NMR chemical shifts and Lewis acidity, evaluated in terms of fluoride ion affinities, are seen only for subsets of silylium ions, sometimes with non‐intuitive trends, indicating a complicated interplay of steric and electronic effects on the degree of the Fe⋅⋅⋅Si interaction.
Cause Analysis of the Non‐Linear Variations of the IGS Reference Station Coordinate Time Series in China
Authors: Wei‐Ping JIANG , Zhao LI , Hong‐Fei LIU , Qian ZHAO 
Published: October 2013

AbstractGPS position time series exhibit dramatic seasonal variations. It is generally considered that atmospheric pressure loading, nontidal ocean loading snow depth and soil moisture loading account for these seasonal changes. Focusing on the 11 IGS reference stations in China, this paper calculates station displacements caused by the above four kinds of surface mass loadings to correct the coordinate time series of these 11 stations during period of 1995–2010 under ITRF2005. We establish a preliminary numerical link among certain geophysical phenomena, seasonal variations and noise characteristics, finding that the calculated four kinds of surface mass loadings could produce variations in station's noise features, mainly exhibiting characteristics of band pass noise and random walk noise, and could reduce the annual amplitude of station's Up component. However, it could not well interpret station's semi‐annual and horizontal annual movement. We investigate the possible factors that could cause non‐linear variations of IGS stations, taking emphasis on the contributions of diurnal (S1) and semi‐diurnal (S2) atmospheric tides to the annual amplitude of the 11 stations, and propose that the S1–S2 atmospheric tides could be one of the main factors for annual motion of IGS stations in China, especially for the vertical annual motion of stations in central and southern regions.
Circulation Variation Over the Western North Pacific and Its Association with Tropical Ssta Over the Indian Ocean and the Pacific
Authors: Hong‐Ming YAN , Qin‐Quan LI , Yuan YUAN , Chong‐Yin LI 
Published: October 2013

AbstractThe circulation variation over the western North Pacific and its relationship between circulation and tropical SSTA were investigated in this paper. The results show that western North Pacific (WNP) anticyclone/cyclone are two significantly anomalous phenomena at mid‐low troposphere over WNP, and their variation is related to PJ wave line and zonal wave line at mid‐high latitudes of Eurasia. Owing to this interrelation, WNP anticyclone/cyclone can influence the climate over East Asia and Eurasia. The results also show that the relationship between WNP anticyclone/cyclone in summer and SSTA is obviously asymmetric. Generally, evident WNP anticyclone occurs in summer of feeble El Niño years, related with warm SSTA in winter of mature El Niño years over the equatorial east Pacific and warm SSTA in spring and summer of weakening El Niño years over the Indian Ocean, which further displays that the WNP anticyclone plays an important bridge role in El Niño event influence on summer climate over East Asia. But the relationship between the obvious WNP cyclone and SSTA in the Indian Ocean is not steady. The formation and maintain of WNP anticyclone are mainly related to anomalous westerlies resulting from thermal contrast between SSTA over the Indian Ocean and SSTA over the Pacific. The possible cause of asymmetry is further investigated. The results show that the thermal contrasts between Indo‐Pacific in El Niño and La Niña summer are accordant, which possibly results in asymmetric relationship between WNP anticyclone/cyclone and SSTA.
The Transformed Hessian Operator in Seismic Inversion Imaging
Authors: Hao‐Ran REN , Hua‐Min ZHOU , Guo‐Xin CHEN , Hua‐Zhong WANG , Sheng‐Chang CHEN 
Published: October 2013

AbstractIn this paper, we summarize the influence of the Hessian operator in seismic inversion methods and review the mathematical and physical meanings of the Hessian operator in the seismic inversion imaging. The Hessian operator is the second derivation of the misfit function to the seismic model parameters. Its Green's function formulation under the acoustic wave approximation shows that the Hessian operator reflects the effects of the seismic acquisition system and wavelet frequency band during the projection of information from the data spaces to the model space. We propose two pseudo‐Hessian forms for the least‐squares migration and the full waveform inversion separately. The application of the plane‐wave Hessian operator can lead to an amplitude‐preserved migration result. The sub‐offset Hessian can be used to the full waveform inversion to enhance the efficiency of inversion. At last, we discuss and evaluate the Hessian operator in seismic inversion imaging.
C‐Met in invasive breast cancer
Authors: Ho‐Yen Colan M. , Green Andrew R. , Rakha Emad A. , Brentnall Adam R. , Ellis Ian O. , Kermorgant Stephanie , Jones J. L. 
Published: October 2013

BACKGROUNDBasal‐like (BL) breast cancer is an aggressive form of breast cancer with limited treatment options. Recent work has identified BL breast cancer as a biologically distinct form of triple‐negative breast cancer, with a worse outlook. The receptor tyrosine kinase c‐Met is a novel therapeutic target associated with reduced survival in breast cancer. Few studies have specifically addressed the association between c‐Met and molecular subtype of breast cancer, yet this is a key consideration when selecting patients for clinical trials. The aim of this study is to evaluate c‐Met expression in a large cohort of invasive breast cancers and in particular, its correlation with molecular subtype.METHODSImmunohistochemistry for c‐Met was performed and evaluated on 1274 invasive breast cancers using tissue microarray technology. The c‐Met scores were correlated with molecular subtype, survival, and other standard clinicopathological prognostic factors.RESULTSMultivariate logistic regression showed c‐Met was independently associated with BL status (odds ratio = 6.44, 95% confidence interval = 1.74‐23.78, P = .005). There was a positive correlation between c‐Met and Her2 (P = .005) and an inverse correlation with tumor size (P < .001). C‐Met was an independent poor prognostic factor at Cox regression analysis in all subtypes (hazard ratio = 1.85, 95% confidence interval = 1.07‐3.19, P = .027) and there was a trend toward reduced survival in BL tumors overexpressing c‐Met, but this was not significant.CONCLUSIONSC‐Met is independently associated with BL breast cancer. In the future, patients with BL tumors should be included in clinical trials of anti‐c‐Met therapy. Cancer 2014;120:163–171. © 2013 American Cancer Society.
Predictors of significant worsening of patient‐reported fatigue over a 1‐month timeframe in ambulatory patients with common solid tumors
Authors: Fisch Michael J. , Zhao Fengmin , O'Mara Ann M. , Wang Xin Shelley , Cella David , Cleeland Charles S. 
Published: October 2013

BACKGROUNDUnderstanding the determinants of fatigue worsening may help distinguish between different fatigue phenotypes and inform clinical trial designs.METHODSPatients with invasive cancer of the breast, prostate, colon/rectum, or lung were enrolled from multiple sites. At enrollment during an outpatient visit and 4 or 5 weeks later, patients rated their symptoms on a numerical rating scale from zero to 10. A 2‐point change on that scale was considered clinically significant for a change in fatigue. Effects of demographic and clinical factors on patient‐reported fatigue were examined using logistic regression models.RESULTSIn total, 3123 patients were enrolled at baseline, and 3032 patients could be analyzed for fatigue change. At baseline, 23% of patients had no fatigue, 35% had mild fatigue, 25% had moderate fatigue, and 17% had severe fatigue. Key parameters in a model of fatigue worsening included fatigue at baseline (odds ratio [OR], 0.75), disease status (OR, 1.99), performance status (OR, 1.38), history of depression (OR, 1.28), patient perception of bother because of comorbidity (OR, 1.26), and treatment exposures, including recent cancer treatment (OR, 1.77) and receipt of corticosteroids (OR, 1.37). The impact of sex was examined only in patients with colorectal and lung cancer, and it was a significant factor, with men most likely to experience worsening of fatigue (OR, 1.46).CONCLUSIONSPredictors of fatigue worsening included multiple factors that were difficult to modify, including the baseline fatigue level, sex, disease status, performance status, recent cancer treatment, bother because of comorbidity, and history of depression. Future fatigue prevention and treatment trial designs should account for key predictors of worsening fatigue. Cancer 2014;120:442–450 © 2013 American Cancer Society.
Efficacy of Antiplatelet Treatment in Stroke Prevention: Past, Present, and Future
Authors: Lukasik Maria , Owecki Michal K. 
Published: October 2013

Abstract

Clinical Development Phases I‐III Regulatory, Quality, Manufacturing

Pharmacological stroke prevention with antithrombotic drugs has evolved since the 1970s. The mechanism of action of the classical antiplatelet drugs is based on the inhibition of one of three strategic platelet activation pathways related to cyclooxygenase action (aspirin), activation of glycoprotein IIb/IIIa by adenosine‐diphosphate via the P2Y12 receptor (thienopyridines), and inhibition of platelet phosphodiesterase (dipyridamole). The effectiveness of antiplatelet drugs was proved in multiple large clinical trials that became the basis for current recommendations. However, the efficacy and especially safety of these drugs are not satisfactory, and research on novel treatment modalities is ongoing. Recently completed or continuing clinical trials dedicated to secondary stroke prevention manifest two directions. One of them involves the search for new antiplatelet drugs and evaluation of their efficacy. The other one is targeted at evaluation of efficacy and safety of dual or even triple antiplatelet therapy. The future of antithrombotic treatment involves platelet function modulation through interactions with the platelet signal transduction pathways. The most advanced studies pertain to inhibitors of platelet kinases: spleen tyrosine kinase (Syk), phosphotidylinositol 3‐kinase, protein kinase C delta and p38 mitogen‐activated protein kinase. Another new therapeutic target may be platelet microRNA particles because their abnormal expression may cause disturbed hemostasis. In the future, it seems that targeted and individualized therapy based on modification of genetically and environmentally conditioned factors that are crucial for prothrombotic properties of platelets might bring definite benefits. Hence, further activities should be focused on designing tools that allow the selection of the antiplatelet therapy balancing benefits and risks as well as cost.
Targeting Platelet G Protein‐Coupled Receptors for Antithrombotic Therapy
Authors: Fälker Knut , Nazare Marc , Wonerow Peter , Kozian Detlef H. 
Published: October 2013

Abstract

Preclinical Research

Platelets are small anucleated cells produced by bone marrow megakaryocytes that circulate in the blood as sentinels of vascular integrity. They play a pivotal role in the regulation of vascular homeostasis through adhesion to the injured vessel wall, aggregation, propagation of coagulation, and thrombus formation. Furthermore, platelets are also involved in fibrinolysis and the repair of the blood vessel wall, restoring blood flow and vascular integrity. Under pathophysiological conditions such as atherosclerosis, inappropriate platelet aggregation and clot formation can cause vascular occlusions, resulting in myocardial infarctions or stroke that, according to the World Health Organization, represent with more than 10% of worldwide death a major health risk (http://who.int/mediacentre/factsheets/fs310/en/). Over the last several decades, increasing efforts have been made to elucidate the cellular components, signaling pathways, and risk factors contributing to platelet activation with the main goal of providing a sound basis for the development of antiplatelet drugs and novel therapeutic treatment strategies. The family of seven transmembrane receptors, also designated G protein‐coupled receptors (GPCRs), represented by approximately 800 members identified in the human genome represent the largest class of receptors and, hence, the richest source of targets for drug discovery. Here, we here provide an overview of the commonly applied therapies targeting platelet‐GPCRs as well as a brief summary of novel approaches.
Phylogeography of the California sheephead, Semicossyphus pulcher: the role of deep reefs as stepping stones and pathways to antitropicality
Authors: Poortvliet Marloes , Longo Gary C. , Selkoe Kimberly , Barber Paul H. , White Crow , Caselle Jennifer E. , Perez‐Matus Alejandro , Gaines Steven D. , Bernardi Giacomo 
Published: October 2013

AbstractIn the past decade, the study of dispersal of marine organisms has shifted from focusing predominantly on the larval stage to a recent interest in adult movement. Antitropical distributions provide a unique system to assess vagility and dispersal. In this study, we have focused on an antitropical wrasse genus, Semicossyphus, which includes the California sheephead, S. pulcher, and Darwin's sheephead, S. darwini. Using a phylogenetic approach based on mitochondrial and nuclear markers, and a population genetic approach based on mitochondrial control region sequences and 10 microsatellite loci, we compared the phylogenetic relationships of these two species, as well as the population genetic characteristics within S. pulcher. While S. pulcher and S. darwini are found in the temperate eastern Pacific regions of the northern and southern hemispheres, respectively, their genetic divergence was very small (estimated to have occurred between 200 and 600 kya). Within S. pulcher, genetic structuring was generally weak, especially along mainland California, but showed weak differentiation between Sea of Cortez and California, and between mainland California and Channel Islands. We highlight the congruence of weak genetic differentiation both within and between species and discuss possible causes for maintenance of high gene flow. In particular, we argue that deep and cooler water refugia are used as stepping stones to connect distant populations, resulting in low levels of genetic differentiation.
Patterns of species diversity and phylogenetic structure of vascular plants on the Qinghai‐Tibetan Plateau
Authors: Yan Yujing , Yang Xian , Tang Zhiyao 
Published: October 2013

AbstractLarge‐scale patterns of species richness and the underlying mechanisms regulating these patterns have long been the central issues in biogeography and macroecology. Phylogenetic community structure is a result of combined effects of contemporary ecological interactions, environmental filtering, and evolutionary history, and it links community ecology with biogeography and trait evolution. The Qinghai‐Tibetan Plateau provides a good opportunity to test the influence of contemporary climate on shaping species richness because of its unique geological history, cold climate, and high biodiversity. In this study, based on high‐resolution distributions of ˜9000 vascular plant species, we explored how species richness and phylogenetic structure of vascular plants correlate with climates on the highest (and species rich) plateau on the Earth. The results showed that most of the vascular plants were distributed on the eastern part of the plateau; there was a strong association between species richness and climate, even after the effects of habitat heterogeneity were controlled. However, the responses of richness to climate remarkably depended on life‐forms. Richness of woody plants showed stronger climatic associations than that of herbaceous plants; energy and water availability together regulated richness pattern of woody plants; whereas water availability predominantly regulated richness pattern of herbaceous plants. The phylogenetic structure of vascular species clustered in most areas of the plateau, suggesting that rapid speciation and environment filtering dominated the assembly of communities on the plateau. We further propose that biodiversity conservation in this area should better take into account ecological features for different life‐forms and phylogenetic lineages.
Analysis of brazilin and protosappanin B in sappan lignum by capillary zone electrophoresis with acid barrage stacking
Authors: Lu Yuanqi , Bai Hong , Kong Chunyan , Zhong Hao , Breadmore Michael C. 
Published: October 2013

A method was developed to determine brazilin and protosappanin B in natural products by CE after acid barrage stacking. The optimum conditions were as follows: a BGE of 20 mM sodium tetraborate (pH 9.2) containing 6% v/v of methanol, hydrodynamic injection (0.5 psi, 65 s) followed by hydrodynamic injection of 150 mM citric acid (pH 2.3; 0.5 psi, 22 s), and separated with +25 kV. Under these conditions, brazilin and protosappanin B were separated with a sample‐to‐sample time less than 13 min and detection limits of 0.28 μg/mL and 0.15 μg/mL, respectively. The applicability of the developed method was demonstrated by the detection of brazilin and protosappanin in methanol extract of sappan lignum.
Experimental investigation of the impacts of coherent flow structures upon turbulence properties in regions of crescentic scour
Authors: Maity Haradhan , Mazumder Bijoy S. 
Published: October 2013

ABSTRACTThis study examines the spatial distributions of third‐order moments of velocity fluctuations, the turbulent kinetic energy (TKE) fluxes, and the conditional statistics of Reynolds shear stress across the equilibrium crescentic scour structures generated upstream of short horizontal static cylinders. Detailed velocity data were collected using three‐dimensional (3D) micro‐acoustic Doppler velocimeter (ADV) across and within the equilibrium scour marks. The analysis reveals that the positive and negative values of third‐order moments associated with the level bed surface and the scour holes are directly related to coherent structures. The components of TKE flux are discussed for the near‐bed region of the level bed surface and scour holes in relation to sweep–ejection events. A cumulant‐discard method is applied to the Gram‐Charlier probability distribution of two variables to describe the statistical properties of the term u′w′. The conditional statistics of the Reynolds shear stress show a good agreement with the experimental data. The distribution of the joint probability density function in the near‐bed region changes cyclically along the scour hole depending on the bottom fluid velocity, which implies a change from upward to downward flux of momentum and vice versa. Both the ejection and sweep events at near‐bed points on the level surface are more important than within the scour region; and in contrast, both events are stronger for the scour marks than the level bed surface at the outer layer. Sweeps dominate over ejections for the scour hole induced by smaller diameter and ejections dominate for larger diameter. Copyright © 2013 John Wiley & Sons, Ltd.
Synergistic effect of static magnetic field and HA‐Fe3O4 magnetic composites on viability of S. aureus and E. coli bacteria
Authors: Bajpai Indu , Balani Kantesh , Basu Bikramjit 
Published: October 2013

AbstractIn addressing the issue of prosthetic infection, this work demonstrated the synergistic effect of the application of static magnetic field (SMF) and ferrimagnetic substrate properties on the bactericidal property in vitro. This aspect was studied using hydroxyapatite (HA)‐xFe3O4 (x=10, 20, and 40 wt.%) substrates, which have different saturation magnetization properties. During bacteria culture experiments, 100 mT SMF was applied to growth medium (with HA‐xFe3O4 substrate) in vitro for 30, 120, and 240 min. A combination of MTT assay, membrane rupture assays, live/dead assay, and fluorescence microscopic analysis showed that the bactericidal effect of SMF increases with the exposure duration as well as increasing Fe3O4 content in biomaterial substrates. Importantly, the synergistic bactericidal effect was found to be independent of bacterial cell type, as similar qualitative trend is measured with both gram negative Escherichia coli (E. coli) and gram positive Staphylococcus aureus (S. aureus) strains. The reduction in E. coli viability was 83% higher on HA‐40 Wt % Fe3O4 composite after 4 h exposure to SMF as compared to nonexposed control. Interestingly, any statistically significant difference in ROS was not observed in bacterial growth medium after magnetic field exposure, indicating the absence of ROS enhancement due to magnetic field. Overall, this study illustrates significant role being played by magnetic substrate compositions towards bactericidal property than by magnetic field exposure alone. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 524–532, 2014.