bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Three Dimensional Electrical Model of PEMFC Stack
Authors: Le Ny M. , Chadebec O. , Cauffet G. , Dedulle J. M. , Bultel Y. 
Published: February 2012

AbstractMathematical modeling is an essential tool in the design of fuel cell systems, as it is important to understand the response of a stack under different conditions. This paper proposes a three dimensional electrical model of PEMFC stack. Such approach highlights the phenomena that occur at the macroscopic scale which are the electrical interactions taking place within the stack. At this scale, the microscopic phenomena are taken into account by averaging them over all the thickness of the membrane electrode assembly (MEA). This model consists of solving the charge transport equation in three dimensions. In order to avoid interfacial issues with the potential jump that occurs in the MEAs, a special source term is added in the transport equation. It makes the model robust, reliable, and helpful for understanding the effect of anomalies on the electric behavior of a PEMFC stack. After describing the equations and the numerical method used for the model, the paper shows some electrical phenomena such as cells interactions, non‐equipotential bipolar plate, higher cell voltages and internal loop of current.
Dynamic Response of a Subsaturated Polymer Electrolyte Fuel Cell in Counterflow Mode
Authors: Bayer M. H. , Schneider I. A. 
Published: February 2012

AbstractThis work demonstrates that the operation of a subsaturated polymer electrolyte fuel cell in counterflow mode results in a significantly elongated relaxation time after a load change, if compared to coflow mode. This effect is investigated here by using combined dynamic locally resolved measurements of the current density, the high frequency resistance, and the relative humidity. It is shown that the elongated relaxation time is a consequence of slow membrane hydration in the region of the cell, downstream the anode flow field, where the diffusive flux of water across the membrane occurs from the anode to the cathode. Here, the anode gas stream, which is humidified upstream the anode flow field via back diffusion of water from the cathode to the anode, is the only source of water for both membrane hydration and the internal humidification of the cathode gas stream, which passes the cell in opposite direction.
Neural integration of speech and gesture in schizophrenia: Evidence for differential processing of metaphoric gestures
Authors: Straube Benjamin , Green Antonia , Sass Katharina , Kirner‐Veselinovic André , Kircher Tilo 
Published: February 2012

AbstractGestures are an important component of interpersonal communication. Especially, complex multimodal communication is assumed to be disrupted in patients with schizophrenia. In healthy subjects, differential neural integration processes for gestures in the context of concrete [iconic (IC) gestures] and abstract sentence contents [metaphoric (MP) gestures] had been demonstrated. With this study we wanted to investigate neural integration processes for both gesture types in patients with schizophrenia. During functional magnetic resonance imaging‐data acquisition, 16 patients with schizophrenia (P) and a healthy control group (C) were shown videos of an actor performing IC and MP gestures and associated sentences. An isolated gesture (G) and isolated sentence condition (S) were included to separate unimodal from bimodal effects at the neural level. During IC conditions (IC > G ∩ IC > S) we found increased activity in the left posterior middle temporal gyrus (pMTG) in both groups. Whereas in the control group the left pMTG and the inferior frontal gyrus (IFG) were activated for the MP conditions (MP > G ∩ MP > S), no significant activation was found for the identical contrast in patients. The interaction of group (P/C) and gesture condition (MP/IC) revealed activation in the bilateral hippocampus, the left middle/superior temporal and IFG. Activation of the pMTG for the IC condition in both groups indicates intact neural integration of IC gestures in schizophrenia. However, failure to activate the left pMTG and IFG for MP co‐verbal gestures suggests a disturbed integration of gestures embedded in an abstract sentence context. This study provides new insight into the neural integration of co‐verbal gestures in patients with schizophrenia. Hum Brain Mapp, 2013. © 2012 Wiley Periodicals, Inc.
Assessing cortical network properties using TMS–EEG
Authors: Rogasch Nigel C. , Fitzgerald Paul B. 
Published: February 2012

AbstractThe past decade has seen significant developments in the concurrent use of transcranial magnetic stimulation (TMS) and electroencephalography (EEG) to directly assess cortical network properties such as excitability and connectivity in humans. New hardware solutions, improved EEG amplifier technology, and advanced data processing techniques have allowed substantial reduction of the TMS‐induced artifact, which had previously rendered concurrent TMS–EEG impossible. Various physiological artifacts resulting from TMS have also been identified, and methods are being developed to either minimize or remove these sources of artifact. With these developments, TMS–EEG has unlocked regions of the cortex to researchers that were previously inaccessible to TMS. By recording the TMS‐evoked response directly from the cortex, TMS–EEG provides information on the excitability, effective connectivity, and oscillatory tuning of a given cortical area, removing the need to infer such measurements from indirect measures. In the following review, we investigate the different online and offline methods for reducing artifacts in TMS–EEG recordings and the physiological information contained within the TMS‐evoked cortical response. We then address the use of TMS–EEG to assess different cortical mechanisms such as cortical inhibition and neural plasticity, before briefly reviewing studies that have utilized TMS–EEG to explore cortical network properties at rest and during different functional brain states. Hum Brain Mapp, 2013. © 2012 Wiley Periodicals, Inc.
Hydrological analysis of the Upper Tiber River Basin, Central Italy: a watershed modelling approach
Authors: Fiseha B. M. , Setegn S. G. , Melesse A. M. , Volpi E. , Fiori A. 
Published: February 2012

AbstractThe quantification of the various components of hydrological processes in a watershed remains a challenging topic as the hydrological system is altered by internal and external drivers. Watershed models have become essential tools to understand the behaviour of a catchment under dynamic processes. In this study, a physically based watershed model called Soil Water Assessment Tool was used to understand the hydrologic behaviour of the Upper Tiber River Basin, Central Italy. The model was successfully calibrated and validated using observed weather and flow data for the period of 1963–1970 and 1971–1978, respectively. Eighteen parameters were evaluated, and the model showed high relative sensitivity to groundwater flow parameters than the surface flow parameters. An analysis of annual hydrological water balance was performed for the entire upper Tiber watershed and selected subbasins. The overall behaviour of the watershed was represented by three categories of parameters governing surface flow, subsurface flow and whole basin response. The base flow contribution has shown that 60% of the streamflow is from shallow aquifer in the subbasins. The model evaluation statistics that evaluate the agreement between the simulated and the observed streamflow at the outlet of a watershed and other three different subbasins has shown a coefficient of determination (R2) from 0.68 to 0.81 and a Nash–Sutcliffe efficiency (ENS) between 0.51 and 0.8 for the validation period. The components of the hydrologic cycle showed variation for dry and wet periods within the watershed for the same parameter sets. On the basis of the calibrated parameters, the model can be used for the prediction of the impact of climate and land use changes and water resources planning and management. Copyright © 2012 John Wiley & Sons, Ltd.
Parametric calibration of the Hargreaves–Samani equation for use at new locations
Authors: Shahidian S. , Serralheiro R.P. , Serrano J. , Teixeira J.L. 
Published: February 2012

AbstractThe Hargreaves–Samani (HS) evapotranspiration equation is very useful for the on‐site irrigation management in data‐short situations such as small and midsize farms and landscaped areas. Although much work has been performed to improve the precision of the evapotranspiration (ETo) estimates for use at new locations, the results have not been consistent and many have not been confirmed by other works. The purpose of this study was to review and to evaluate the seven most promising parameters used for the calibration of the HS evapotranspiration equation, using two different regions: California and Bolivia. The results of this study show that annual correlations between HS and Penman–Monteith can be misleading because the correlation is poor in the humid months and improves progressively along the dry season until the first rains. The average monthly wind speed can be used for both spatial and seasonal calibration of the HS equation, especially during the irrigation season. Elevation and precipitation can be used to calibrate the HS equation when no reference ETo values are available at nearby stations. The monthly value of KT calculated from solar radiation follows a parabolic function along the year and should not be used for improving the estimates of the HS equation because the clearness index produces better results than actual solar radiation measurements. The results also indicate that the use of distance to coast, temperature range and temperature parameter does not improve the precision of the HS equation. Copyright © 2012 John Wiley & Sons, Ltd.
Yukon River Basin long‐term (1977–2006) hydrologic and climatic analysis
Authors: Ge Shaoqing , Yang Daqing , Kane Douglas L. 
Published: February 2012

AbstractIn this study, long‐term discharge data and climate records, such as temperature and precipitation during 1977–2006, have been used to define basin climatic and hydrologic regimes and changes. Discharge analyses at four key gauging stations (Eagle, Stevens Village, Nenana, and Pilot Station) in the Yukon River Basin show that the runoff in the cold season (November to April) is low with small variations, whereas it is high (28 500–177 000 ft3/s; 810–5000 m3/s) with high fluctuations in the warm season (May to October). The Stevens Village Station is in the upper basin and has similar changes with the flow near basin outlet. Flow increases in May (61 074 ft3/s; 1729 m3/s) and September (23 325 ft3/s; 660 m3/s); and decreases in July (35 174 ft3/s; 996 m3/s) and August (6809 ft3/s; 193 m3/s). Discharge in May at the Pilot Station (near the basin outlet) shows a positive trend (177 000 ft3/s; 5010 m3/s). Daily flow analyses show high fluctuation during the warm season and very low flow during the cold season; the 10‐year average analyses of daily flow at Pilot Station show a small increase in the peak and its timing shifted to a little earlier date. The annual flow, average of 227 900 ft3/s (6450 m3/s) with high inter‐annual fluctuations, has increased by 18 200 ft3/s (or 8%; 520 m3/s) during 1977–2006. From 1977 to 2006, basin air temperature in June has increased by 3.9 °F (2.2 °C) and decreased by 10.5 °F (5.8 °C) in January. A strong and positive correlation exists between air temperature in April and discharge in May, whereas a strong and negative correlation relates August temperature and September discharge. Negative trend during 1977–2006 is observed for precipitation in June (0.6 in.; 15 mm) with a confidence over 93%. Precipitation in August and September has strong and positive correlations with discharge in September and October at basin outlet; the precipitation in other months has weak correlation with the discharge. The mean annual precipitation during 1977–2006 increased by 1.1 in. (or 8%; 28 mm), which contributes to the annual flow increase during the study period. Copyright © 2012 John Wiley & Sons, Ltd.
GROSS DOMESTIC PRODUCT GROWTH PREDICTIONS THROUGH THE YIELD SPREAD: TIME‐VARIATION AND STRUCTURAL BREAKS
Authors: Pace Pierangelo De 
Published: February 2012

ABSTRACTWe use time‐varying‐parameter models and real‐time data to describe the evolution of the leading properties of the yield spread for output growth in five European economies and in the USA over the last decades and until the third quarter of 2010. We evaluate the predictive performance of benchmark term‐structure models and identify structural breaks in the marginal processes of term spreads and government bond yields to shed light on the dynamic characteristics of the yield curve. Econometric analysis shows that (i) the predictive content of the term spread is not always significant over time and across countries; (ii) the spread significantly contributes to the forecast performance of simple growth regressions in Europe but not in the USA in recent years; and (iii) the variance of the random shocks to the term spreads tends to fall in all countries. This decline is accompanied by vanishing leading properties from the mid‐1990s. Such properties reappear after 2008. Copyright © 2012 John Wiley & Sons, Ltd.
Acquired immunogenicity of human DNA damaged by N‐hydroxy‐N‐acetyl‐4‐aminobiphenyl
Authors: Shahab Uzma , Moinuddin  , Ahmad Saheem , Dixit Kiran , Abidi S.M. Abbas , Alam Khursheed , Ali Asif 
Published: February 2012

Abstract4‐Aminobiphenyl, a known carcinogen, has many environmental sources like cigarette smoke, industrial waste, and so forth. It can be metabolized to form a potent mutagen, N‐hydroxy‐N‐acetyl‐4‐aminobiphenyl (N‐OH‐AABP) that undergoes further processing to form electrophilic nitrenium ions which interact with DNA‐forming covalent adducts, thereby exerting genotoxic effects. While the mutagenicity of N‐OH‐AABP has been amply reported, no extensive studies have been performed to assess the immunogenicity of N‐OH‐AABP‐modified DNA. In this study, human placental DNA was modified with N‐OH‐AABP, and the structural perturbations in the DNA molecule were evaluated by ultraviolet spectroscopy and nuclease S1 digestion. Native and N‐OH‐AABP‐modified DNA were used as antigens for immunizing female rabbits. The modified DNA was found to be highly immunogenic, eliciting high titer immunogen‐specific antibodies, while the native form was almost nonimmunogenic. The induced antibodies exhibited wide range of heterogeneity in recognizing various nucleic acid conformers and DNA bases. We also detected deposits of immune complex in glomerular basement membrane in rabbits immunized with N‐OH‐AABP‐DNA. Possible role of N‐OH‐AABP‐DNA in the induction of antibodies in cancer patients and the related consequences have been discussed. © 2012 IUBMB Life, 64(4): 340–345, 2012
Consequences of two naturally occurring missense mutations in the structure and function of Bruton agammaglobulinemia tyrosine kinase
Authors: Vargas‐Hernández Alexander , López‐Herrera Gabriela , Maravillas‐Montero José L. , Vences‐Catalán Felipe , Mogica‐Martínez Dolores , Rojo‐Domínguez Arturo , Espinosa‐Rosales Francisco J. , Santos‐Argumedo Leopoldo 
Published: February 2012

AbstractBruton agammaglobulinemia tyrosine kinase (BTK) is a key protein in the B‐cell receptor (BCR) signaling pathway and plays an essential role in the differentiation of B lymphocytes. X‐linked agammaglobulinemia (XLA) is a primary humoral immunodeficiency caused by mutations in the gene encoding BTK. Previously, we identified two novel variations, L111P and E605G, in BTK; these are localized within the pleckstrin homology and Src homology 1 domains, respectively. In the present study, we evaluated the potential effects of these variations on the structural conformation and the function of BTK. Using in silico methods, we found that the L111P and E650G variations are not located directly in protein–protein interfaces but close to them. They distorted the native structural conformation of the BTK protein, affecting not only its geometry and stability but also its ability for protein recognition and in consequence its functionality. To confirm the results of the in silico assays, WT BTK, L111P, and E650G variants were expressed in the BTK‐deficient DT40 cell line. The mutant proteins exhibited an absence of catalytic activity, aberrant redistribution after BCR‐crosslinking, and deficient intracellular calcium mobilization. This work demonstrates that L111 and E605 residues are fundamental for the activation and function of BTK. © 2012 IUBMB Life, 64(4): 346–353, 2012
A cellular delivery system fabricated with autologous BMSCs and collagen scaffold enhances angiogenesis and perfusion in ischemic hind limb
Authors: Wang Jinling , Cui Wugeng , Ye Jianhong , Ji Shufeng , Zhao Xiufeng , Zhan Linghui , Feng Jiachun , Zhang Zhigang , Zhao Yilin 
Published: February 2012

AbstractAlthough therapeutic cellular angiogenesis is effective for chronic ischemia, the optimal mode of cellular administration is still under exploration. This study aimed to develop a cellular delivery system to enhance the perfusion and angiogenesis in the ischemic hind limb. Collagen scaffold (CS) was prepared, and for morphology and toxicity analysis, bone marrow‐derived mesenchymal stem cells (BMSCs) were isolated, expanded, filtrated, and seeded onto CS to construct BMSCs–CS. The ischemic hind limbs of rabbit models were implanted with autologous BMSCs–CS, CS, and autologous BMSCs; the untreated ischemic or normal animals were considered as the ischemic or normal control groups. Oxygen saturation parameters were regularly measured to determine the perfusion in the extremities. Histological examinations with hematoxylin and eosin immunostaining against von Willebrand factor and smooth muscle (SM) α‐actin were performed for capillary and mature vessel evaluation. CS was a multiporous structure without cytotoxicity. At several intervals, the oxygen saturation ratio (OSR) in normal control was the highest. The OSRs in BMSCs–CS and CS were higher than that in BMSCs and ischemic control (p< 0.05); the OSR in BMSCs–CS group was higher than that in CS at 6 and 8 weeks (p< 0.05). The capillaries in BMSCs–CS and CS were higher than that in CS, BMSCs, and the ischemic or normal control (p< 0.05). The mature vessels in BMSCs–CS were higher than that in CS, BMSCs, and the ischemic or normal control (p< 0.05). The autologous cellular delivery system proved to be an effective approach for improving higher ischemic hind limb perfusion and angiogenesis as opposed to cellular therapy alone. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.
Preparation and characterization of decellularized tendon slices for tendon tissue engineering
Authors: Ning Liang‐Ju , Zhang Yi , Chen Xiao‐He , Luo Jing‐Cong , Li Xiu‐Qun , Yang Zhi‐Ming , Qin Ting‐Wu 
Published: February 2012

AbstractTo develop a naturally derived tendon tissue engineering scaffold with the preservation of the native ultrastructure, tensile strength, and biochemical composition of the tendon extracellular matrix (ECM), decellularized tendon slices (DTSs) were prepared using repetitive freeze/thaw of the intact Achilles tendons, frozen section, and nuclease treatment. The DTSs were characterized in the native ultrastructure, mechanical properties, biochemical composition, and cytocompatibility. Histological examination and DNA quantification analysis confirmed that cells were completely removed from tendon tissue by repetitive freeze/thaw in combination with nuclease treatment 12 h. The intrinsic ultrastructure of tendon tissue was well preserved based on scanning electron microscopy examination. The tensile strength of the DTSs was retained 85.62% of native tendon slice. More than 93% of proteoglycans (fibromodulin, biglycan) and growth factors (TGF‐β1, IGF‐1, VEGF, and CTGF) inherent in tendon ECM were preserved in the DTSs according to ELISA analysis. Furthermore, the DTSs facilitated attachment and repopulation of NIH‐3T3 fibroblasts in vitro. Overall, the DTSs are sheet scaffolds with a combination of elemental mechanical strength and tendon ECM bioactive factors that may have many potential applications in tendon tissue engineering. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2012.
Reduced adenosine release from the aged mammalian heart
Authors: Fenton Richard A. , Dobson James G. 
Published: February 2012

AbstractAdenosine (ADO) released in the heart results in enhanced coronary blood flow and reduced catecholamine release and myocardial responsiveness to adrenergic stimulation (anti‐adrenergic action). ADO release from the adrenergic‐stimulated aged heart is less than that from the young adult heart. Because adrenergic signaling in the aged heart is impaired, this study was conducted to determine if reduced ADO release from the aged heart results from this reduced adrenergic responsiveness. Hearts of 3–4 months (young adult) and 21–22 months (aged) Fischer‐344 rats were perfused with ADO deamination and re‐phosphorylation inhibited. Coronary effluent ADO levels were determined. Cellular‐free ADO levels with and without sodium acetate (NaAc)‐induced mitochondrial AMP synthesis were assessed using formed S‐adenosylhomocysteine (SAH) in L‐homocysteine thiolactone (L‐HC)‐treated hearts. The activities of SAH‐hydrolase were determined. Aged heart ADO release was 61% less than from young hearts. NaAc augmented young heart ADO release by 104%, while that of aged hearts remained unchanged. SAH synthesis was 51% and 56% lower in the aged heart in the absence and presence of NaAc, respectively, despite an 89% greater SAH hydrolase activity found in the aged hearts. Since synthesized AMP may be diverted to IMP and ultimately inosine by AMP deaminase, inosine release was determined. Aged heart inosine levels in the absence and presence of NaAc were 74% and 59% less than for the young hearts. It is concluded that a reduced mitochondrial AMP synthesis is in part responsible for the attenuation in ADO release from the adrenergic‐stimulated aged heart. J. Cell. Physiol. 227: 3709–3714, 2012. © 2012 Wiley Periodicals, Inc.
New insights on translational development of mesenchymal stromal cells for suppressor therapy
Authors: François Moïra , Galipeau Jacques 
Published: February 2012

AbstractThe discovery of the immunosuppressive properties of mesenchymal stromal cells (MSCs) has given new hope to patients suffering from autoimmune diseases as their lack of immunogenicity in addition to their immunosuppressive and regenerative properties makes them an ideal biological agent for the treatment of various disorders ranging from autoimmune diseases to tissue injury. The translational promises of a safer and more effective therapy has however suffered a setback with the recent release of the results from Phase III randomized clinical trial using MSCs for treatment of steroid refractory acute graft‐versus‐host disease (GvHD), which failed to meet its primary efficacy endpoint. In this review, we will address the current knowledge of the immunosuppressive mechanisms of MSCs from in vitro studies to animal models and then look upon the results obtained from human clinical trials in order to provide failure analysis of negative studies. We will conclude by proposing future directions which could help address this issue and allow rational development of MSCs as an effective and useful cell‐based immunotherapeutic. J. Cell. Physiol. 227: 3535–3538, 2012. © 2012 Wiley Periodicals, Inc.