bluuebunny/crossref_metadata_2025_split huggingface dataset:
Configuration Path Integral Monte Carlo
Authors: Schoof T. , Bonitz M. , Filinov A. , Hochstuhl D. , Dufty J.W. 
Published: April 2011

AbstractA novel path integral Monte Carlo (PIMC) approach for correlated many‐particle systems with arbitrary pair interaction in continuous space at low temperatures is presented. It is based on a representation of the N ‐particle density operator in a basis of (anti‐)symmetrized N ‐particle states (configurations of occupation numbers). The path integral is transformed into a sum over trajectories with the same topology and, finally, the limit of M → ∞, where M is the number of high‐temperature factors, is analytically performed. This yields exact expressions for the thermodynamic quantities and allows to perform efficient simulations for fermions at low temperature and weak to moderate coupling. Our method is expected to be applicable to dense quantum plasmas in the regime of strong degeneracy where conventional PIMC fails due to the fermion sign problem (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Joint precoding and power allocation for multiuser transmission in MIMO relay networks
Authors: Jiang Dongmei , Zhang Haixia , Yuan Dongfeng 
Published: April 2011

SUMMARYThis paper proposes a joint precoding and power allocation strategy to maximize the sum rate of multiuser multiple‐input multiple‐output (MIMO) relay networks. A two‐hop relay link working on amplify‐and‐forward (AF) mode is considered. Precoding and power allocation are designed jointly at the base station (BS). It is assumed that there are no direct links between the BS and users. Under individual power constraints at the BS and relay station, precoders designed based on zero forcing, minimum mean‐square error and maximum ratio transmission are derived, respectively. Optimal power allocation strategies for these precoders are given separately. To demonstrate the performance of the proposed strategies, we simulate the uncoded bit error rate performance of the underlined system. We also show the difference of the sum rate of the system with the optimal power allocation strategies and with average power transmission. The simulation results show the advantages of the proposed joint precoding and power allocation strategies as expected. Copyright © 2011 John Wiley & Sons, Ltd.
Rap1a activation by CalDAG‐GEFI and p38 MAPK is involved in E‐selectin‐dependent slow leukocyte rolling
Authors: Stadtmann Anika , Brinkhaus Laura , Mueller Helena , Rossaint Jan , Bolomini‐Vittori Matteo , Bergmeier Wolfgang , Van Aken Hugo , Wagner Denisa D. , Laudanna Carlo , Ley Klaus , Zarbock Alexander 
Published: April 2011

AbstractRolling leukocytes are exposed to different adhesion molecules and chemokines. Neutrophils rolling on E‐selectin induce integrin αLβ2‐mediated slow rolling on ICAM‐1 by activating a phospholipase C (PLC)γ2‐dependent and a separate PI3Kγ‐dependent pathway. E‐selectin‐signaling cooperates with chemokine signaling to recruit neutrophils into inflamed tissues. However, the distal signaling pathway linking PLCγ2 (Plcg2) to αLβ2‐activation is unknown. To identify this pathway, we used different Tat‐fusion‐mutants and gene‐deficient mice in intravital microscopy, autoperfused flow chamber, peritonitis, and biochemical studies. We found that the small GTPase Rap1 is activated following E‐selectin engagement and that blocking Rap1a in Pik3cg−/− mice by a dominant‐negative Tat‐fusion mutant completely abolished E‐selectin‐mediated slow rolling. We identified CalDAG‐GEFI (Rasgrp2) and p38 MAPK as key signaling intermediates between PLCγ2 and Rap1a. Gαi‐independent leukocyte adhesion to and transmigration through endothelial cells in inflamed postcapillary venules of the cremaster muscle were completely abolished in Rasgrp2−/− mice. The physiological importance of CalDAG‐GEFI in E‐selectin‐dependent integrin activation is shown by complete inhibition of neutrophil recruitment into the inflamed peritoneal cavity of Rasgrp2−/− leukocytes treated with pertussis toxin to block Gαi‐signaling. Our data demonstrate that Rap1a activation by p38 MAPK and CalDAG‐GEFI is involved in E‐selectin‐dependent slow rolling and leukocyte recruitment.
High‐order compact scheme for Boussinesq equations: implementation and numerical boundary condition issue
Authors: Ghader S. , Ghasemi A. , Banazadeh M. R. , Mansoury D. 
Published: April 2011

SUMMARYApplication of the three‐point fourth‐order compact scheme to spatial differencing of the vorticity‐stream function‐density formulation of the two‐dimensional incompressible Boussinesq equations is presented. The details for the derivation of difference relations at boundaries to generate accurate and stable solutions are also given. To assess the numerical accuracy, two linear prototype test problems with known exact solution are used. The two‐dimensional planar and cylindrical lock‐exchange flow configurations are used to conduct the numerical experiments for the Boussinesq equations. Quantitative measures for the two linear prototype test problems and comparison of the results of this work with the published results for the planar lock‐exchange flow indicates the validity and accuracy of the three‐point fourth‐order compact scheme for numerical solution of two‐dimensional incompressible Boussinesq equations. In addition, the study of using different high‐order numerical boundary conditions for the implementation of the no‐penetration boundary condition for the density at no‐slip walls is considered. It is shown that the numerical solution is sensitive to the choice of difference relation for the density at boundaries and using an inappropriate difference relation leads to spurious numerical solution. Copyright © 2011 John Wiley & Sons, Ltd.
The management of heat flow in deep mines (part 2)
Authors: Wagner Horst 
Published: April 2011

AbstractIn Part 1 of “The Management of Heat Flow in Deep Mines” the sources of heat, mechanism of heat transfer and strategies of controlling heat transfer have been discussed. Part 2 deals with the effects of heat on the human body and mine cooling strategies for deep mines. In detail the effects of heat on a worker are examined, heat stress and heat tolerance discussed and methods of assessing heat stress in different mining situations presented. Experiences from deep South African gold mines highlight the adverse effects of heat stress environment on safety and labour productivity. The principal methods of cooling of deep and ultra deep mines are discussed. It is shown that auto‐compression of ventilation air is a deciding factor governing the choice of surface or underground cooling of ventilation air. In the case of deep and ultra deep mines, the use of chilled service water and ice slurry has shown to be the most cost effective means of mine cooling. In the case of ice slurry as cooling medium advantage is taken of the latent heat of ice which significantly reduces the amount of water required for mine cooling and hence the cost of pumping the water to surface. Cooling strategies for moderately deep, deep and ultra deep mines are discussed. Examples of cooling of deep long mine tunnels are given.
Kopswerk II headrace tunnel – geomechanical and construction design / Triebwasserstollen Kopswerk II – geomechanische und bautechnische Planung
Authors: Vigl Alois , Barwart C. 
Published: April 2011

AbstractThe Kopswerk II power plant of the Vorarlberger Illwerke AG with a capacity of 510 MW was constructed between 2004 and 2008 as a pumped storage scheme parallel to the existing Kopswerk I (247 MW) constructed in 1969. The design of the headrace was confronted with borderline conditions concerning both construction and operation. The construction concept had to take into consideration the external constraints and ensure continuous construction in winter in the high mountains. On account of the formation water situation, the intention was to relieve formation water pressure during the construction period.In operation, the components of the headrace system including pressure tunnel are subject to enormous internal pressure fluctuations within a very short time on account of the pumped storage peak flow operation of Kopswerk II. In addition, the external formation water pressure can reach a head of 450 m, which could scarcely be resisted with an economic lining alone. This resulted in a basic design concept to integrate the surrounding rock mass into the structural system as far as possible, both with regard to rock pressure and formation water pressure. Such a concept has to include systematic and differentiated grouting of the rock mass, which is not always simple to achieve under high formation water pressure.Das Kopswerk II der Vorarlberger Illwerke AG mit einer Leistung von 510 MW wurde in den Jahren 2004 bis 2008 parallel zum seit 1969 bestehenden Kopswerk I (247 MW) als Pumpspeicherwerk neu errichtet. Die Planung der Oberwasserführung war sowohl im Hinblick auf die Errichtung wie auch auf den Betrieb mit grenzwertigen Bedingungen konfrontiert. Das Baukonzept musste hinsichtlich der äußeren Bedingungen einen Durchlaufbetrieb im Winter und im Hochgebirge ermöglichen. Hinsichtlich der Bergwassersituation war eine Entlastung des Bergwasserdrucks während der Bauarbeiten anzustreben.Im Betrieb unterliegen die Komponenten der Oberwasserführung einschließlich Druckstollen wegen des Pumpspeicher‐ Spitzenstrom‐Einsatzes des Kopswerks II enormen Innendruckschwankungen innerhalb kürzester Zeitspannen. Zudem steht von außen ein Bergwasser‐Druckpotenzial von bis zu 450 m Wassersäule an, das durch eine wirtschaftliche Auskleidung allein kaum zu beherrschen wäre. Somit musste ein planerisches Grundkonzept verfolgt werden, welches das umgebende Gebirge möglichst weitgehend in das Tragkonzept mit einbezieht und zwar sowohl hinsichtlich Gebirgslast wie auch hinsichtlich Bergwasserdruck. Ein solches Konzept schließt eine systematische und differenzierte Gebirgsbehandlung mittels Injektionen konsequent ein, was unter Bergwasserandrang nicht immer leicht umsetzbar ist.
Serum levels of polychlorinated biphenyls in Mexican women and breast cancer risk
Authors: Recio‐Vega Rogelio , Velazco‐Rodriguez Victor , Ocampo‐Gómez Guadalupe , Hernandez‐Gonzalez Sandra , Ruiz‐Flores Pablo , Lopez‐Marquez Francisco 
Published: April 2011

ABSTRACTThe most prevalent female cancer across the world is breast cancer. Current established breast cancer risk factors explain only a fraction of the breast cancer cases diagnosed, and for this reason, other environmental factors have been studied. Exposure to organochlorine compounds has been linked to an increased incidence of breast cancer, although not all data have been consistent. This study was designed to evaluate the relation between polychlorinated biphenyls (PCB) exposure and breast cancer risk in Mexican women. We recruited 140 women from the General Hospital. The cases were 70 newly diagnosed women. We collected environmental and reproductive information by questionnaire. Blood samples were taken for measurement of serum levels of 20 PCB congeners. Risk of breast cancer was found to be positively associated with heavy congeners, age, postmenopausal status, family history of breast cancer and living close to an industrial facility. When PCB were grouped by structure–activity relationships, the risk of breast cancer was positively associated with groups 2b (odds ratio, OR = 1.90, 95% confidence interval, CI, 1.25–2.88), 3 (OR = 1.81, 95% CI 1.08–3.04) and group 4 (OR = 1.57, 95% CI 1.20–2.07). Among postmenopausal women, PCB levels from groups 1a, 2b, and 4 and total PCB were higher in cases, and an association between risk of breast cancer with groups 1a (OR = 7.59, 95% CI 1.1–51.4), 2b (OR = 3.7, 95% CI 1.2–11.2) and 4 (OR = 1.8, 95% CI 1.1–3.1) was found in this group of women. This study showed an association between heavy and potentially estrogenic PCB congeners and breast cancer risk. Copyright © 2011 John Wiley & Sons, Ltd.
Role of stereoelectronic features of imine and enamine in (S)‐proline catalyzed mannich reaction of acetaldehyde: An in silico study
Authors: Ajitha Manjaly J. , Suresh Cherumuttathu H. 
Published: April 2011

AbstractA detailed mechanistic investigation of sixteen possible diastereomeric pathways for the C‐C bond formation step in (S)‐proline catalyzed Mannich reaction of acetaldehyde with N‐acetyl protected benzaldimine in acetonitrile solvent has been carried out to understand how stereoelectronic features invoke enantioselectivity of the final product. Both kinetic and thermodynamic factors of the reaction obtained using various density functional theory methods point out that si‐enantiofacial nucleophilic attack of anti‐enamine on the iminium carbon of the E, s‐cis N‐acetyl protected imine is the stereoselective pathway. Structural features of the transition states predicted that enamine in anti conformation attacks the imine through a Burgi‐Dunitz trajectory to yield the stereocenter. Computations at B3LYP‐PCM/6‐311++G(3df,2p)//B3LYP‐PCM/6‐31G(d,p) level showed a strong linear correlation between Burgi‐Dunitz angle and activation energy when anti‐enamine is used as nucleophile to react with all the configurations of the imine. Further, energy decomposition analysis has been carried out at B3LYP/TZ2P+ level for all the transition states, which revealed that the most dominant factor that control the enantioselectivity of the (S)‐proline catalyzed Mannich reaction is steric effect. Though the less favored transition states showed high amount of stabilizing orbital interaction, the destabilizing steric effects from both Pauli repulsion and preparation energy for the reactant molecules are very high and overshadowed the stabilizing effects. However, in the most favored transition state, a balanced outcome of electronic and steric effects was observed. Solvation effect was nearly same for all the transition states and electrostatic effects showed no correlation to the rank order of the energy of the transition states. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011.
Risk factor model to predict venous thromboembolism in hospitalized medical patients
Authors: Rothberg Michael B. , Lindenauer Peter K. , Lahti Maureen , Pekow Penelope S. , Selker Harry P. 
Published: April 2011

AbstractBACKGROUND:The Joint Commission requires that all medical inpatients be assessed for venous thromboembolism (VTE) risk, but available risk stratification tools have never been validated.METHODS:We conducted a retrospective cohort study of patients age ≥18 years, admitted to 374 US hospitals in 2004–2005, with a primary diagnosis of pneumonia, heart failure, chronic obstructive pulmonary disease (COPD), stroke, and urinary tract infection, and length of stay ≥3 days. Subjects were randomly assigned (80/20) to a derivation or validation set. We then assessed VTE (International Classification of Diseases, Ninth Revision [ICD‐9] code plus diagnostic test plus treatment), patient demographics, 21 potential risk factors, and other comorbidities. We created a VTE risk stratification tool using multivariable regression modeling and applied it to the validation sample.RESULTS:Of 242,738 patients, 612 (0.25%) patients fulfilled our criteria for VTE during hospitalization, and an additional 440 (0.18%) were readmitted for VTE within 30 days (overall incidence of 0.43%). In the multivariable model, age, sex, and 10 additional risk factors were associated with VTE. The strongest risk factors were inherited thrombophilia (OR 4.00), length of stay ≥6 days (OR 3.22), inflammatory bowel disease (OR 3.11), central venous catheter (OR 1.87), and cancer. In the validation set, the model had a c‐statistic of 0.75 (95% CI 0.71, 0.78). Deciles of predicted risk ranged from 0.11% to 1.46% with observed risk over the same deciles from 0.17% to 1.81%.CONCLUSIONS:The risk of symptomatic VTE in general medical patients is low. A risk factor model can identify those at sufficient risk to warrant pharmacologic prophylaxis. Journal of Hospital Medicine 2011. © 2011 Society of Hospital Medicine.
ENSO‐conditioned rainfall drought frequency analysis in northwest Baja California, Mexico
Authors: Hallack‐Alegria M. , Ramirez‐Hernandez J. , Watkins D. W. 
Published: April 2011

AbstractLocated in northwest Baja California, Mexico, the Guadalupe River Basin is situated in a semiarid region where periods of drought pose serious economic, social and environmental concerns. The study area has highly variable climate, with mean annual precipitation ranging from less than 12 mm to over 750 mm a year across the basin, and with most of the annual precipitation occurring during the autumn and winter seasons. To quantify the frequency and severity of meteorological droughts at the local (watershed) scale, this study investigates seasonal and annual precipitation data from 34 sites in northwest Baja California. Along with the analysis of precipitation climatology and interannual variability, El Niño/Southern Oscillation (ENSO) and related Pacific Ocean sea surface temperature (SST) patterns are shown to be potential predictors of seasonal precipitation. Analysis of precipitation variability at seasonal and annual time scales is performed using the standardized precipitation index (SPI) methodology, and annual, seasonal, and ENSO‐conditioned precipitation frequency analyses are executed using the regional L‐moment algorithm. The SPI and regional rainfall drought frequency estimates developed in this study may be useful for monitoring meteorological droughts and could serve as critical components of a comprehensive drought management plan. Furthermore, the methods applied in this study may be transferred to other semi‐arid locations to mitigate drought risk and, potentially, impacts of drier conditions in the 21st century. Copyright © 2011 Royal Meteorological Society
Immune response to cancer and its regulation in regional lymph nodes
Authors: Zheng Rongxiu , Shu Suyu 
Published: April 2011

AbstractRegional draining lymph nodes (LNs) play a pivotal role in initiating immune responses. However, the presence of metastases may compromise their normal immunological function. Preclinical studies indicate that despite metastases, early tumor‐draining LNs are still a rich source of sensitized T cells. Recently, we found that dendritic (DC)‐tumor fusion hybrids were capable of stimulating therapeutic T‐cell generation in the LN. However, this response is regulated by a tumor‐specific suppression mechanism(s). Reversal of these dysfunctions would help the success of immunotherapy. J. Surg. Oncol. 2011;103:550–554. © 2011 Wiley‐Liss, Inc.
Thyroid cancer and lymph node metastases
Authors: Clark Orlo H. 
Published: April 2011

AbstractThere is considerable controversy about the prognostic implications of lymph node metastases in patients with papillary thyroid cancer and whether patients with papillary thyroid cancer should have a prophylactic or selective central (level VI) neck dissection. Some experts report that a prophylactic ipsilateral neck dissection results in fewer patients having elevated thyroglobulin levels but others do not agree. A comprehensive review of the literature suggests that the presence of macroscopic metastases of papillary thyroid cancer in cervical lymph nodes results in a higher recurrence rate and increased death rate, especially in patients 45 years of age or older, whereas microscopic nodal metastases do not appear to adversely influence survival. Until more information is available we recommend preoperative ultrasonography and a selective ipsilateral neck dissection for patients with papillary thyroid cancer. J. Surg. Oncol. 2011;103:615–618. © 2011 Wiley‐Liss, Inc.
The prognostic significance of the insulin‐like growth factor‐1 ligand and receptor expression in breast cancer tissue
Authors: Chong Kelvin Y.M. , Subramanian Ashok , Mokbel Kefah , Sharma Anup K. 
Published: April 2011

AbstractBackground and ObjectivesPrevious in vitro studies have suggested that IGF‐1 stimulation can lead a more aggressive breast cancers and subsequent poor prognosis in breast cancer patients. We aim to how IGF‐1 and IGF‐1R mRNA levels in breast cancer are associated with disease‐free survival (DFS) and other clinicopathological factors.MethodsIGF‐1 and IGF‐1R mRNA levels were measured in breast cancer tissue from 132 patients using real‐time PCR. DFS and clinicopathological information were obtained from patient case notes.ResultsIGF‐1 and IGF‐1R mRNA levels did not correlate with any clinicopathological factors. Patients who relapsed had lower IGF‐1 mRNA levels in their tumour tissue compared to those who remained disease‐free during the 5‐year follow‐up period. Patients who had ER‐positive breast cancers with high IGF‐1 mRNA levels had longer DFS compared to those with low IGF‐1 mRNA levels. IGF‐1 mRNA levels was not associated with DFS in patients with ER‐negative cancers. IGF‐1R mRNA levels was not associated with DFS in any subgroup analysis. Multivariate analysis showed that IGF‐1 mRNA levels and histopathological grade were independent predictors of DFS.ConclusionsBreast cancer tissue IGF‐1 expression is a favourable prognostic indicator and could be used in clinical setting in planning for adjuvant treatment. J. Surg. Oncol. 2011; 104:228–235. © 2011 Wiley‐Liss, Inc.
Ultraviolet radiation and 12‐O‐tetradecanoylphorbol‐13‐acetate‐induced interaction of mouse epidermal protein kinase Cε with Stat3 involve integration with ERK1/2
Authors: Sand Jordan Marshall , Hafeez Bilal Bin , Aziz Moammir Hasan , Siebers Emily Marie , Dreckschmidt Nancy Ellen , Verma Ajit Kumar 
Published: April 2011

AbstractWe have reported that protein kinase C epsilon (PKCε) expression level in epidermis dictates the susceptibility of mice to the development of squamous cell carcinomas (SCC) elicited either by repeated exposure to ultraviolet radiation (UVR) or by the DMBA‐TPA tumor promotion protocol. To find clues about the mechanism by which PKCε mediates susceptibility to UVR‐induced development of SCC, we found that PKCε‐over‐expressing transgenic mice, as compared to their wild‐type littermates, when exposed to UVR, elicit enhanced phosphorylation of Stat3 at Ser727 residues. Stat3 is constitutively activated in SCC and UVR fails to induce SCC in Stat3 mutant mice. Stat3Ser727 phosphorylation is essential for Stat3 transcriptional activity (Cancer Res. 67: 1385, 2007). We now present several novel findings including that PKCε integrates with its downstream partner ERK1/2 to phosphorylate Stat3Ser727. In these experiments, mice were either exposed to UVR (2 kJ/m2/dose) emitted by Kodacel‐filtered FS‐40 sun lamps or treated with TPA (5 nmol). Both UVR and TPA treatment stimulated PKCε–Stat3 interaction, Stat3Ser727 phosphorylation and Stat3‐regulated gene COX‐2 expression. PKCε–Stat3 interaction and Stat3Ser727 phosphorylation was also observed in SCC elicited by repeated UVR exposures of mice. PKCε–Stat3 interaction was PKCε specific. UVR or TPA‐stimulated Stat3Ser727 phosphorylation accompanied interaction of PKCε with ERK1/2 in intact mouse skin in vivo. Deletion of PKCε in wild‐type mice attenuated both TPA and UVR‐induced expression of phosphoforms of ERK1/2 and Stat3Ser727. These results indicate that PKCε integrates with ERK1/2 to mediate both TPA and UVR‐induced epidermal Stat3Ser727 phosphorylation. PKCε and Stat3 may be potential molecular targets for SCC prevention. © 2011 Wiley Periodicals, Inc.