bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stimulation of transient receptor potential vanilloid 4 channel suppresses abnormal activation of microglia induced by lipopolysaccharide
Authors: Konno Masakazu , Shirakawa Hisashi , Iida Shota , Sakimoto Shinya , Matsutani Ikkei , Miyake Takahito , Kageyama Keiko , Nakagawa Takayuki , Shibasaki Koji , Kaneko Shuji 
Published: February 2012

AbstractMicroglia are intrinsic immune cells in the brain. In response to neurodegenerative events, excessively activated microglia change their shapes and release various cytokines leading to the pathogenesis of central nervous system (CNS) disease. Because the intracellular mechanisms of this process are still unclear, we have evaluated the functional roles of transient receptor potential vanilloid 4 (TRPV4) channel expressed in the microglia. Robust microglial activation after an injection of lipopolysaccharide (LPS) into the mouse cerebral ventricle was suppressed by concurrent administration of a selective TRPV4 agonist, 4α‐phorbol 12,13‐didecanoate (4α‐PDD). When the mechanism was further investigated using cultured rat microglia intrinsically expressing functional TRPV4, release of tumor necrosis factor‐α (TNF‐α) and expression of galectin‐3 were both increased by LPS. These increases were significantly suppressed by cotreatment with 4α‐PDD, and the inhibitory effects of 4α‐PDD were abolished by knockdown of TRPV4 or TRPV4 antagonists. The amplitude of voltage‐dependent K+ current, which is augmented during microglial activation, was also suppressed by 4α‐PDD treatment. Opening of TRPV4 channels with 4α‐PDD induced membrane depolarization mainly by increasing Na+ influx. In addition, mimicking depolarization with a high‐K+ solution suppressed LPS‐induced TNF‐α release and galectin‐3 upregulation. Both depolarizing treatments with 4α‐PDD and high‐K+ solution decreased store‐operated Ca2+ influx caused by thapsigargin. These results suggest that depolarization in response to opening of the TRPV4 channel attenuates the driving force for extracellular Ca2+ and suppresses microglial activation. © 2012 Wiley Periodicals, Inc.
A ‘core‐periphery’ framework to navigate emerging market governments—qualitative evidence from a biotechnology multinational
Authors: Prithwiraj Choudhury , James A. Geraghty , Tarun Khanna 
Published: February 2012

AbstractWe build on the emerging literature of influence‐based models to study how multinational firms can navigate host governments. Our ‘core‐periphery’ framework posits that the actions that an MNC takes with actors in what we call the ‘periphery’—comprised of state, quasi‐state, and civil society actors—can lead to positive or negative influence with interconnected state actors in a ‘core.’ There are two mechanisms by which this can happen: engaging the periphery may either change the information set of the core or help align incentives of multiple core actors. Engaging the periphery might be particularly relevant in settings where the institutional framework is still emerging. We build a case study of a multinational firm in the biotechnology sector to illustrate how the core‐periphery framework works in multiple emerging markets across institutional differences. The analysis is based on 32 interviews conducted with the CEO and other executives of Genzyme at the corporate headquarters in Cambridge, Massachusetts, and in subsidiaries in Brazil, China, Costa Rica, France, India, and the United States.
Acquisitions as entrepreneurship: asymmetries, opportunities, and the internationalization of multinationals from emerging economies
Authors: Madhok Anoop , Keyhani Mohammad 
Published: February 2012

AbstractWe investigate the rapid internationalization of many multinationals from emerging economies through acquisition in advanced economies. We conceptualize these acquisitions as an act and form of entrepreneurship, aimed to overcome the ‘liability of emergingness’ incurred by these firms and to serve as a mechanism for competitive catch‐up through opportunity seeking and capability transformation. Our explanation emphasizes (1) the unique asymmetries (and not necessarily advantages) distinguishing emerging multinationals from advanced economy multinationals due to their historical and institutional differences, as well as (2) a search for advantage creation when firms possess mainly ordinary resources. The argument shifts the central focus from advantage to asymmetries as the starting point for internationalization and, additionally, highlights the role of learning agility rather than ability as a potential ‘asset of emergingness.’
Imag(in)ing seizure propagation: MEG‐guided interpretation of epileptic activity from a deep source
Authors: Wang Zhong I. , Jin Kazutaka , Kakisaka Yosuke , Mosher John C. , Bingaman William E. , Kotagal Prakash , Burgess Richard C. , Najm Imad M. , Alexopoulos Andreas V. 
Published: February 2012

AbstractIdentification and accurate localization of seizure foci is vital in patients with medically‐intractable focal epilepsy, who may be candidates for potentially curative resective epilepsy surgery. We present a patient with difficult‐to‐control seizures associated with an occult focal cortical dysplasia residing within the deeper left parietal operculum and underlying posterior insula, which was not detected by conventional MRI analysis. Propagated activities from this deeper generator produced misleading EEG patterns both on surface and subdural electrode recordings suggesting initial activation of the perirolandic and mesial frontal regions. However, careful spatio‐temporal analysis of stereotyped interictal activities recorded during MEG, using sequential dipole modeling, revealed a consistent pattern of epileptic propagation originating from the deeper source and propagating within few milliseconds to the dorsal convexity. In this instance, careful dissection of noninvasive investigations (interictal MEG along with ictal SPECT findings) allowed clinicians to dismiss the inaccurate and misleading findings of the traditional “gold‐standard” intracranial EEG. In fact, this multimodal noninvasive approach uncovered a subtle dysplastic lesion, resection of which rendered the patient seizure‐free. This case highlights the potential benefits of dynamic analysis of interictal MEG in the appropriate clinical context. Pathways of interictal spike propagation may help elucidate essential neural networks underlying focal epilepsy. Hum Brain Mapp, 2012. © 2012 Wiley Periodicals, Inc
Investigating causality between interacting brain areas with multivariate autoregressive models of MEG sensor data
Authors: Michalareas George , Schoffelen Jan‐Mathijs , Paterson Gavin , Gross Joachim 
Published: February 2012

AbstractIn this work, we investigate the feasibility to estimating causal interactions between brain regions based on multivariate autoregressive models (MAR models) fitted to magnetoencephalographic (MEG) sensor measurements. We first demonstrate the theoretical feasibility of estimating source level causal interactions after projection of the sensor‐level model coefficients onto the locations of the neural sources. Next, we show with simulated MEG data that causality, as measured by partial directed coherence (PDC), can be correctly reconstructed if the locations of the interacting brain areas are known. We further demonstrate, if a very large number of brain voxels is considered as potential activation sources, that PDC as a measure to reconstruct causal interactions is less accurate. In such case the MAR model coefficients alone contain meaningful causality information. The proposed method overcomes the problems of model nonrobustness and large computation times encountered during causality analysis by existing methods. These methods first project MEG sensor time‐series onto a large number of brain locations after which the MAR model is built on this large number of source‐level time‐series. Instead, through this work, we demonstrate that by building the MAR model on the sensor‐level and then projecting only the MAR coefficients in source space, the true casual pathways are recovered even when a very large number of locations are considered as sources. The main contribution of this work is that by this methodology entire brain causality maps can be efficiently derived without any a priori selection of regions of interest. Hum Brain Mapp, 2013. © 2012 Wiley Periodicals, Inc.
Review and management of drug interactions with boceprevir and telaprevir
Authors: Kiser Jennifer J. , Burton James R. , Anderson Peter L. , Everson Gregory T. 
Published: February 2012

Abstract

Boceprevir (BOC) and telaprevir (TPV), when added to pegylated interferon and ribavirin for the treatment of chronic hepatitis C virus (HCV) infection, increase the rates of sustained virologic response in treatment-naïve persons to approximately 70%. Though these agents represent an important advance in the treatment of chronic HCV, they present new treatment challenges to the hepatology community. BOC and TPV are both substrates and inhibitors of the hepatic enzyme, cytochrome P450 3A, and the drug transporter, P-glycoprotein, which predisposes these agents to many drug interactions. Identification and appropriate management of potential drug interactions with TPV and BOC is critical for optimizing therapeutic outcomes during hepatitis C treatment. This review highlights the pharmacologic characteristics and drug-interaction potential of BOC and TPV and provides guidance on the management of drug interactions with these agents. (Hepatology 2012;)
Multivariate statistical analysis and environmental isotopes of Amman/Wadi Sir (B2/A7) groundwater, Yarmouk River Basin, Jordan
Authors: Obeidat Mutewekil Mamdouh , Awawdeh Muheeb , Abu Al‐Rub Fahmi 
Published: February 2012

AbstractMultivariate statistical techniques, cluster and factor analyses were applied on the Amman/Wadi Sir groundwater chemistry, Yarmouk River basin, north Jordan. The main objective was to investigate the main processes affecting the groundwater chemical quality and its evolution. The k‐means cluster analysis yields three groups with distinct ionic concentrations. Cluster 1 comprises the vast majority of the sampled wells, and the water that belongs to this cluster can be classified as freshwater. Cluster 2 comprises only 2% of the sampled wells; it has the highest ionic concentration. The water of this cluster can be classified as brackish water. Cluster 3 involves 23% of the sampled wells, and it has total ionic concentration intermediate to that of clusters 1 and 2. Factor analysis yields a three‐factor model, which explains 76.77% of the groundwater quality variation. Factor 1 ‘salinity factor’ involves EC, Na+, Cl‐, SO4‐2, K+ and Mg+2 and reflects groundwater salinization because of overpumping. Factor 2 ‘hardness factor’ includes Ca+2, HCO3‐ and the pH value and signifies soil–water/rock interaction. Factor 3 ‘nitrate factor’ involves only NO3‐ and points to groundwater contamination because of human activities, mainly untreated wastewater, and crops and animal cultivation in the unconfined portion of the aquifer. Factors 1 and 3 can be described as human‐induced factors, whereas factor 2 can be described as geogenic factor. Factors' scores were mapped to deduce the controlling processes on the groundwater chemistry. Stable isotope composition of 18O and 2H has revealed that the groundwater is a mixture of two water types. The radioactive isotopes tritium and 14 C were used to evaluate present day recharge to the aquifer and to estimate the groundwater age, respectively. Present day recharge to the groundwater is taking place in the unconfined portion of the aquifer as it is indicated by the measurable tritium content and low groundwater age. Copyright © 2012 John Wiley & Sons, Ltd.
Evaluation of a nonparametric post‐processor for bias correction and uncertainty estimation of hydrologic predictions
Authors: Brown James D. , Seo Dong‐Jun 
Published: February 2012

AbstractThis paper evaluates a nonparametric technique for estimating the conditional probability distribution of a predictand given a vector of predictors. In the current application, the predictors are formed from a multimodel ensemble of simulated streamflows, such that the hydrologic uncertainties are modelled independently of any forcing uncertainties. The technique is based on Bayesian optimal linear estimation of indicator variables and is analogous to indicator cokriging (ICK) in geostatistics. By developing linear estimators for the conditional probability that the observed variable does not exceed several thresholds, ICK provides a discrete approximation of the full conditional probability distribution. The weights of the predictors can be chosen to minimize the expected error variance at each threshold (the Brier score) or, without loss of analytical tractability, a combination of the error variance and the expected square bias conditional upon the observation, i.e. the Type‐II conditional bias (CB). The latter is referred to as CB‐penalized ICK (CBP‐ICK) and is an important enhancement to ICK. Indeed, the biases in atmospheric and hydrologic predictions generally increase towards the tails of their probability distributions. The performance of CBP‐ICK is evaluated for selected basins in the eastern USA using a range of probabilistic verification metrics and associated confidence intervals for the sampling uncertainties. Overall, CBP‐ICK produces unbiased and skillful estimates of the hydrologic uncertainties, with some sensitivity to the calibration data period at high flow thresholds. More generally, we argue that the common aim in statistical post‐processing of ‘maximizing sharpness subject to reliability (Type‐I CB)’ should be recast to accommodate both the Type‐I and Type‐II CBs, as both are important for practical applications of hydrologic predictions. Copyright © 2012 John Wiley & Sons, Ltd.
Inhibition of lung tumor development by berry extracts in mice exposed to cigarette smoke
Authors: Balansky Roumen , Ganchev Gancho , Iltcheva Marietta , Kratchanova Maria , Denev Petko , Kratchanov Christo , Polasa Kalpagam , D'Agostini Francesco , Steele Vernon E. , De Flora Silvio 
Published: February 2012

AbstractCigarette smoke (CS) and dietary factors play a major role in cancer epidemiology. At the same time, however, the diet is the richest source of anticancer agents. Berries possess a broad array of health protective properties and were found to attenuate the yield of tumors induced by individual carcinogens in the rodent digestive tract and mammary gland but failed to prevent lung tumors induced by typical CS components in mice. We exposed whole‐body Swiss ICR mice to mainstream CS, starting at birth and continuing daily for 4 months. Aqueous extracts of black chokeberry and strawberry were given as the only source of drinking water, starting after weaning and continuing for 7 months, thus mimicking an intervention in current smokers. In the absence of berries, CS caused a loss of body weight, induced early cytogenetical damage in circulating erythrocytes and histopathological alterations in lung (emphysema, blood vessel proliferation, alveolar epithelial hyperplasia and adenomas), liver (parenchymal degeneration) and urinary bladder (epithelial hyperplasia). Both berry extracts inhibited the CS‐related body weight loss, cytogenetical damage, liver degeneration, pulmonary emphysema and lung adenomas. Protective effects were more pronounced in female mice, which may be ascribed to modulation by berry components of the metabolism of estrogens implicated in lung carcinogenesis. Interestingly, both the carcinogen and the chemopreventive agents tested are complex mixtures that contain a multitude of components working through composite mechanisms.
Dermal carotenoid measurements via pressure mediated reflection spectroscopy
Authors: Ermakov Igor V. , Gellermann Werner 
Published: February 2012

AbstractWe describe a reflection‐based method for the quantitative detection of carotenoid antioxidants in living human skin. The skin tissue site of interest is illuminated with broad‐band white light spanning the spectral range from 350–850 nm and the spectral composition of the diffusively reflected light is analyzed in real time. Topical pressure is applied to temporarily squeeze blood out of the illuminated tissue volume. In this way the influence of oxy‐hemoglobin on the reflection spectra is effectively reduced. After a short optical clearing time the carotenoid absorption becomes easily discernable in a 460–500 nm spectral window and its optical density can be calculated with high accuracy. Our empirical methodology provides a non‐invasive rapid determination of skin carotenoid levels, can be used to monitor skin carotenoid concentration changes over time in response to carotenoid containing natural or supplemental diets, and is easily adaptable for applications in clinical and field settings. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparative proteomic analysis of differentiation of mouse F9 embryonic carcinoma cells induced by retinoic acid
Authors: Jiao Rui‐Qing , Li Guanwu , Chiu Jen‐Fu 
Published: February 2012

AbstractThe multipotent mouse F9 embryonic carcinoma cell is an ideal model system to investigate the mechanism of retinoic acid (RA) in cell differentiation and cell growth control and the biochemical basis of early embryonic development. We reported here a proteomics approach to study protein expression changes during the differentiation of F9 cells into the visceral endoderm. F9 cells were incubated with or without RA at 0, 24, 48, and 72 h. Total proteins extracted were separated by two‐dimensional electrophoresis (2‐DE) and the protein patterns on the gels were comparatively analyzed by computer. Approximately 1,100 protein spots were detected in the F9 proteome, within the pH 3–10 range. Fourteen protein spots which the levels of expression were found to be altered dramatically during the F9 cells differentiating, and were identified by MALDI‐TOF MS or ESI‐MS/MS. These proteins included metabolism enzymes, HSP60s, RAN, hnRNP K, FUBP1, VDAC1, STI1, and prohibitin. These proteins are involved in cellar metabolism, gene expression regulation, stress response, and apoptosis, respectively. The data from proteomic analyze are consistent with the result obtained from Western blot analysis. This study increases our understanding of the proteomics changes during F9 cells differentiation induced by RA. J. Cell. Biochem. 113: 1811–1819, 2012. © 2012 Wiley Periodicals, Inc.
Density functional study of electronic,bonding, and vibrational properties of Ca (NH2BH3)2
Authors: Lingam Ch. Bheema , Babu K. Ramesh , Tewari Surya P. , Vaitheeswaran G. 
Published: February 2012

AbstractWe present structural, electronic, bonding and vibrational properties of new type hydrogen storage material calcium amidoborane ${\rm Ca}({\rm NH}_{2}{\rm BH}_{3})_{2}$ by first principles density functional theory using plane wave pseudopotential method. The calculated ground state properties are in good agreement with experiments. The computed Bulk modulus of ${\rm Ca}({\rm NH}_{2}{\rm BH}_{3})_{2}$ is found to be 28.7 GPa which is slightly higher than that of ${\rm NH}_{3}{\rm BH}_{3}$ indicating that the material is hard over ${\rm NH}_{3}{\rm BH}_{3}$. From the band structure calculations, the compound is found to be a direct band gap insulator with a band gap of 3.27 eV at the Γ point. The calculated bandstructure shows that the top of the valance band is from the p states of N and the bottom of the conduction band is from d states of Ca. The Mulliken bond populations, Born effective charges and charge density distributions are used to analyze the bonding nature of the compound. It is found that the N‐H and B‐H bonds are covalent in nature. Further we also compared the phonon density of states and vibrational frequencies of ${\rm Ca}({\rm NH}_{2}{\rm BH}_{3})_{2}$ with ${\rm NH}_{3}{\rm BH}_{3}$. The study reveals that in both the cases the heavier mass atoms Ca, N, B are involved in the low frequency vibrations whereas the higher frequency vibrations are from H atoms. It is also observed that the vibrational frequencies of B‐H bonds are soft in ${\rm Ca}({\rm NH}_{2}{\rm BH}_{3})_{2}$ when compared to ${\rm NH}_{3}{\rm BH}_{3}$ and thereby concluded that ${\rm Ca}({\rm NH}_{2}{\rm BH}_{3})_{2}$ is a potential hydrogen storage material for fuel cell applications when compared to ${\rm NH}_{3}{\rm BH}_{3}$. © 2012 Wiley Periodicals, Inc.
Oxidases and reactive oxygen species during hematopoiesis: A focus on megakaryocytes
Authors: Eliades Alexia , Matsuura Shinobu , Ravid Katya 
Published: February 2012

AbstractReactive oxygen species (ROS), generated as a result of various reactions, control an array of cellular processes. The role of ROS during megakaryocyte (MK) development has been a subject of interest and research. The bone marrow niche is a site of MK differentiation and maturation. In this environment, a gradient of oxygen tension, from normoxia to hypoxia results in different levels of ROS, impacting cellular physiology. This article provides an overview of major sources of ROS, their implication in different signaling pathways, and their effect on cellular physiology, with a focus on megakaryopoiesis. The importance of ROS‐generating oxidases in MK biology and pathology, including myelofibrosis, is also described. J. Cell. Physiol. 227: 3355–3362, 2012. © 2012 Wiley Periodicals, Inc.
Seasonal Variations of Steroid Hormones and Triiodothyronine Concentrations in Migratory Northern Shovelers
Authors: ELARABANY N. F. , ABDALLAH G. A. , SAID A. E. 
Published: February 2012

ABSTRACTEndogenous serum testosterone, estradiol, and triiodothyronine concentrations were measured in the northern shoveler (Anas clypeata,n = 20) during different stages of migratory condition at their wintering grounds to look at how these hormones may be linked to the development of migratory condition. These hormones were assayed by enzyme‐linked immunosorbent assay (ELISA). The changes in hormones concentrations were parallel to each other and correspond to the increasing day lengths of spring. Furthermore, the northern shovelers showed a distinct seasonal cycle in serum concentrations of triiodothyronine, estradiol, and testosterone. It is suggested that these seasonal cycles in the northern shovelers are endogenously programmed and their entrainment to the environmental photoperiod ensures the occurrence of different physiological functions at temporally fixed time of the year. The results of this study offer a captive model of the seasonal changes in physiology and behavior that occur in the months preceding and including vernal migration of the northern shovelers. J. Exp. Zool. 317:216–226, 2012. © 2012 Wiley Periodicals, Inc.