bluuebunny/crossref_metadata_2025_split huggingface dataset:
Depolarization of the membrane potential by hyaluronan
Authors: Hagenfeld Daniel , Schulz Tobias , Ehling Petra , Budde Thomas , Schumacher Udo , Prehm Peter 
Published: July 2010

AbstractThe membrane potential is mainly maintained by the K+ concentration gradient across the cell membrane between the cytosol and the extracellular matrix. Here, we show that extracellular addition of high‐molecular weight hyaluronan depolarized the membrane potential of human fibroblasts, human embryonic kidney cells (HEK), and central nervous system neurons in a concentration‐dependent manner, whereas digestion of cell surface hyaluronan by hyaluronidase caused hyperpolarization. This effect could not be achieved by other glycosaminoglycans or hyaluronan oligosaccharides, chondroitin sulfate, and heparin which did not affect the membrane potential. Mixtures of high‐molecular weight hyaluronan and bovine serum albumin had a larger depolarization effect than expected as the sum of both individual components. The different behavior of high‐molecular weight hyaluronan versus hyaluronan oligosaccharides and other glycosaminoglycans can be explained by a Donnan effect combined with a steric exclusion of other molecules from the water solvated chains of high‐molecular weight hyaluronan. Depolarization of the plasma membrane by hyaluronan represents an additional pathway of signal transduction to the classical CD44 signal transduction pathway, which links the extracellular matrix to intracellular metabolism. J. Cell. Biochem. 111: 858–864, 2010. © 2010 Wiley‐Liss, Inc.
Effects of platelets on the protein expression in aortic segments: A proteomic approach
Authors: Modrego Javier , Moñux Guillermo , Mateos‐Cáceres Petra J. , Martínez‐López Isaac , Segura Antonio , Zamorano‐León José J. , Rodríguez‐Sierra Pablo , Serrano Javier , Macaya Carlos , López‐Farré Antonio J. 
Published: July 2010

AbstractIt is well known the effects of the vascular wall on platelet activity but little is known about the effects of platelets on the proteins expression in the vascular wall. We analyzed whether platelets may modify the protein expression in the vascular wall. We used an in vitro model coincubating human platelet rich plasma (PRP) with control and 10 ng/ml tumor necrosis factor‐α (TNF‐α)‐preincubated bovine aortic segments. 2DE, mass spectrometry and Western blot analysis were used to determine changes in the expression of proteins associated with the cytoskeleton and energetic metabolism in the aortic segments. In control healthy vascular wall, only the cytoskeleton‐related proteins expression was modified by PRP. However, when PRP was coincubated with TNF‐α pre‐stimulated aortic segments lesser number of cytoskeleton‐related proteins were modified. With respect to energetic metabolism, in control segments, PRP failed to modify any of the analyzed energetic‐related proteins. However, in TNF‐α‐preincubated segments the presence of PRP upexpressed glyceraldehyde‐3‐phosphate dehydrogenase. Moreover, by western blot experiments it was observed that in TNF‐α‐preincubated segments the expression of fructose 1,6‐bisphosphate aldolase was downregulated by platelets. However, no differences were found in the expression of triosephosphate isomerase and ATP synthase α‐chain. In addition, the activity of fructose 1,6‐bisphosphate aldolase and piruvate content was significantly reduced without modification on triosephosphate isomerase activity. In conclusion, the crosstalk between platelets and vascular wall is bidirectional and platelets regulated in the vascular wall the expression of proteins associated with the cytoskeleton and energetic metabolism, particularly in the healthy vascular wall. J. Cell. Biochem. 111: 889–898, 2010. © 2010 Wiley‐Liss, Inc.
Novel batch reactor design for the adsorption of arsenate on chitosan
Authors: Kwok Katrina C.M. , McKay Gordon 
Published: July 2010

AbstractBACKGROUND: The sorption of arsenate, a poison of acute toxicity found in natural waters, onto chitosan, a biosorbent derived from waste seafood shells has been studied. A batch adsorber design model was developed to determine how much chitosan adsorbent is required to reduce the arsenate concentration in solutions to the WHO standard of 10 µg L−1.RESULTS: A series of batch kinetic experiments has been carried out at different initial pH values. The initial arsenate sorption appears to be completed after 30 min, however, a steady reversible reaction takes place resulting in the desorption of arsenate over 48 h. These phenomena in the batch kinetic data have been correlated simultaneously using the newly developed pseudo‐first order reversible model. Two batch reactor design models have been developed and compared. The first model is a conventional approach based on the equilibrium isotherm capacity equation. A second batch adsorption reactor design is based on the principle of contacting time required, tmax, for the chitosan to achieve its maximum adsorption capacity, qmax. The practical outcome from the second batch adsorber model results in a saving in adsorbent mass per batch of approximately 39.4%, 96.2% and 92.3% chitosan adsorbent at pH conditions of 3.5, 4.0 and 5.0, respectively.CONCLUSION: The adsorbent cost and handling costs are reduced in the second batch adsorber model. There is also a significant savings in the batch turnaround time required in the batch adsorber design when the design is based on the maximum adsorption capacity rather than the equilibrium adsorption capacity. Copyright © 2010 Society of Chemical Industry
Development of ambient sampling chemi/chemical ion source with dielectric barrier discharge
Authors: Chen Lee Chuin , Yu Zhan , Furuya Hiroko , Hashimoto Yutaka , Takekawa Kenichi , Suzuki Hiroaki , Ariyada Osamu , Hiraoka Kenzo 
Published: July 2010

AbstractThe development of a new configuration of chemical ionization (CI)‐based ion source is presented. The ambient air containing the gaseous sample is sniffed into an enclosed ionization chamber which is of sub‐ambient pressure, and is subsequently mixed with metastable species in front of the ion inlet of the mass spectrometer. Metastable helium atoms (He*) are used in this study as the primary ionizing agents and are generated from a dielectric barrier discharge (DBD) source. The DBD is powered by an AC high‐voltage supply and the configuration of the electrodes is in such a way that the generated plasma is confined within the discharge tube and is not extended into the ionization chamber. The construction of the ion source is simple, and volatile compounds released from the bulky sample can also be analyzed directly by approaching the sample to the sampling nozzle. When combined with heated nitrogen or other desorption methods, its application can also be extended to non‐volatile compounds, and the consumption for helium can be kept minimum solely for maintaining the stable discharge and gas phase ionization. Applications to non‐proximate sample analysis, direct determination of active ingredients in drug tablets and the detection of trace explosive such as hexamethylene triperoxide diamine are demonstrated. Copyright © 2010 John Wiley & Sons, Ltd.
Some critical aspects in the determination of binding constants by electrospray ionisation mass spectrometry at the example of arsenic bindings to sulphur‐containing biomolecules
Authors: Schmidt Anne‐Christine , Steier Sandra 
Published: July 2010

AbstractThe influences of reactant concentrations, solvent type, acid strength, pH conditions and ionic strength on the determination of apparent gas‐phase equilibrium constants K using electrospray ionisation mass spectrometry (ESI‐MS) were elucidated. As example serves the interaction of the tripeptide glutathione (GSH) with phenylarsine oxide (PAO). It was shown that rising initial concentrations of both reactants were not adequately compensated by increasing signal intensities of the reaction products in the mass spectra. The equilibrium constant for the formation of the phenylarsenic‐substituted peptide species decreased from 1.42 × 105 ± 1.81 × 104 l µmol−1 to 1.54 × 104 ± 1.5 × 103 l µmol−1 with rising initial GSH concentrations from 1 to 10 µM at fixed PAO molarity of 50 µM. K values resulting from a series with a fixed GSH molarity of 5 µM and a PAO molarity varied from 10 to 100 µM remained in a narrower range between 4.59 × 104 ± 2.15 × 104 l µmol−1 and 1.07 × 104 ± 4.0 × 103 l µmol−1. In contrast, consumption numbers calculated from the ion intensity ratios of reaction products to the unreacted peptide were not influenced by the initial reactant concentrations. In a water–acetonitrile–acetic acid mixture (48:50:2, v:v), the consumption of 5 µ M GSH increased from 8.3 ± 1.4% to 39.6 ± 1.6% with increased molar excess of PAO from 2 to 20, respectively. The GSH consumption was considerably enhanced in a changed solvent system consisting of 25% acetonitrile and 75% 10 mM ammonium formate, pH 5.0 (v:v) up to 80% of the original peptide amount at an only threefold molar arsenic excess. Copyright © 2010 John Wiley & Sons, Ltd.
Deimination stabilizes histone H2A/H2B dimers as revealed by electrospray ionization mass spectrometry
Authors: Shimoyama Shingo , Nagadoi Aritaka , Tachiwana Hiroaki , Yamada Michiyuki , Sato Mamoru , Kurumizaka Hitoshi , Nishimura Yoshifumi , Akashi Satoko 
Published: July 2010

AbstractPost‐translational modifications of histones for reversibly changing chromosomal structures in promoter regions of genes are a prerequisite for transcriptional activation and repression of genes. Peptidylarginine deiminase 4 (PAD4), which mediates histone deimination by converting arginine residues into citrulline residues, is involved in the repression of gene transcription. However, the mechanism is still unclear. We studied the effects of deimination on the reconstituted histone H2A/H2B dimer structure by electrospray ionization mass spectrometry. Deimination of the H2A/H2B dimer by PAD4 indicated that the mass of H2A increased 2.7 Da, suggesting that two or three Arg residues of H2A were deiminated. Deimination of H2A monomer alone showed a 6.6‐Da increase in mass. This indicates that about four more Arg residues of H2A are modified in the monomer state than in the H2A/H2B dimer state. Taking account of the finding that the unstructured portions in proteins are susceptible to deimination by PAD4, it is likely that H2A in the monomer state has a more flexible structure than that in the dimer state. Furthermore, analysis of the association of the H2A/H2B dimer in 2 or 4 M ammonium acetate with nano‐electrospray ionization mass spectrometry showed that a modified H2A/H2B dimer was less dissociated into H2A and H2B monomers than an unmodified dimer when high voltages were applied to the sample cone. This study provides convincing evidence that PAD4 deimination stabilizes the histone H2A/H2B dimer. Copyright © 2010 John Wiley & Sons, Ltd.
Induction of bone marrow mesenchymal stem cell chondrogenesis following short‐term suspension culture
Authors: Kisiday John D. , Lee Christina M. , McIlwraith C. Wayne , Frisbie David D. 
Published: July 2010

AbstractThe objective of this study was to evaluate mesenchymal stem cell (MSC) chondrogenesis following incubation in chondrogenic suspension cultures from which single cells were obtained. MSCs were maintained in suspension over a nonadherent surface for 3 days, dissociated into a suspension, and then evaluated for chondrogenesis in agarose in the presence or absence of transforming growth factor beta (TGFβ). In a second experiment, MSCs from suspension culture were returned to monolayer expansion for 2 days prior to testing for chondrogenesis. In both cases, undifferentiated MSCs were evaluated as controls. Suspension culture alone did not stimulate chondrogenesis. Suspension followed by expansion stimulated a four‐ to ninefold increase in extracellular matrix (ECM) synthesis in TGFβ‐free cultures, a finding that was attributed to an increase in viable MSCs that secreted a proteoglycan‐rich ECM. Gene expression of aggrecan and type II collagen increased with suspension culture, but decreased with postsuspension expansion. Therefore, stimulation of ECM synthesis without additional TGFβ exposure could not be attributed to an enhancement of chondrogenesis with monolayer culture. ECM synthesis of suspension/expansion‐conditioned MSCs without additional TGFβ exposure was less than samples maintained in TGFβ throughout the differentiation culture. Based on these findings, a better understanding of factors associated with early‐stage chondrogenesis and MSC differentiation to a highly active phenotype may lead to improved methods for stimulating chondrogenesis during short‐term culture. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29:26–32, 2011
Interleukin‐17 synergizes with IFNγ or TNFα to promote inflammatory mediator release and intercellular adhesion molecule‐1 (ICAM‐1) expression in human intervertebral disc cells
Authors: Gabr Mostafa A. , Jing Liufang , Helbling Antonia R. , Sinclair S. Michael , Allen Kyle D. , Shamji Mohammed F. , Richardson William J. , Fitch Robert D. , Setton Lori A. , Chen Jun 
Published: July 2010

AbstractInterleukin‐17 (IL‐17) is a cytokine recently shown to be elevated, along with interferon‐γ (IFNγ) and tumor necrosis factor (TNFα), in degenerated and herniated intervertebral disc (IVD) tissues, suggesting a role for these cytokines in intervertebral disc disease. The objective of our study was to investigate the involvement of IL‐17 and costimulants IFNγ and TNFα in intervertebral disc pathology. Cells were isolated from anulus fibrosus and nucleus pulposus tissues of patients undergoing surgery for intervertebral disc degeneration or scoliosis. The production of inflammatory mediators, nitric oxide (NOx), prostaglandin E2 (PGE2) and interleukin‐6 (IL‐6), as well as intercellular adhesion molecule (ICAM‐1) expression, were quantified for cultured cells following exposure to IL‐17, IFNγ, and TNFα. Intervertebral disc cells exposed to IL‐17, IFNγ, or TNFα showed a remarkable increase in inflammatory mediator release and ICAM‐1 expression (GLM and ANOVA, p < 0.05). Addition of IFNγ or TNFα to IL‐17 demonstrated a synergistic increase in inflammatory mediator release, and a marked increase in ICAM‐1 expression. These findings suggest that IVD cells not only respond with a catabolic phenotype to IL‐17 and costimulants IFNγ and TNFα, but also express surface ligands with consequent potential to recruit additional lymphocytes and immune cells to the IVD microenvironment. IL‐17 may be an important regulator of inflammation in the IVD pathologies. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29:1–7, 2011
Robotic testing of proximal tibio‐fibular joint kinematics for measuring instability following total knee arthroplasty
Authors: Barsoum Wael K. , Lee Ho H. , Murray Trevor G. , Colbrunn Robb , Klika Alison K. , Butler S. , van den Bogert Antonie J. 
Published: July 2010

AbstractPain secondary to instability in total knee arthroplasty (TKA) has been shown to be major cause of early failure. In this study, we focused on the effect of instability in TKA on the proximal tibio‐fibular joint (PTFJ). We used a robotics model to compare the biomechanics of the PTFJ in the native knee, an appropriately balanced TKA, and an unbalanced TKA. The tibia (n = 5) was mounted to a six‐degree‐of‐freedom force/torque sensor and the femur was moved by a robotic manipulator. Motion at the PTFJ was recorded with a high‐resolution digital camera system. After establishing a neutral position, loading conditions were applied at varying flexion angles (0°, 30°, and 60°). These included: internal/external rotation (0 Nm, ±5 Nm), varus/valgus (0 Nm, ±10 Nm), compression (100 N, 700 N), and posterior drawer (0 N, 100 N). With respect to anterior displacement, external rotation had the largest effect (coefficient = 0.650; p < 0.0001). Polyethylene size as well as the interaction between polyethylene size and flexion consistently showed substantial anterior motion. Flexion and mid‐flexion instability in TKA have been difficult to quantify. While tibio‐femoral kinematics is the main aspect of TKA performance, the effects on adjacent tissues should not be overlooked. Our data show that PTFJ kinematics are affected by the balancing of the TKA. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29:47–52, 2011
Knowledge management in secondary care: a case study
Authors: Zigan Krystin , Macfarlane Fraser , Desombre Terry 
Published: July 2010

AbstractThe purpose of this research is to analyse the knowledge management activities of a university hospital and to examine what impact contextual factors have on these activities. For this research, a case study approach was chosen, encompassing 22 semi‐structured interviews with managers and front‐line staff from different organisational levels. The findings describe how at the top management level, knowledge management activities were neglected while at departmental level, such activities were purposefully undertaken. This suggests that knowledge management activities can be effectively implemented at departmental level without having the support and strategic objective of the top management of the hospital. The findings further show that factors, such as the effective utilisation of other intangible resources, such as social capital, highly contribute to the effectiveness of knowledge management activities. The paper shows some limitations due to the qualitative nature of the research with regard to sample size and the subjectivity of the interpretations. The paper proposes that knowledge management activities can be implemented in organisations, when having the right attitude of staff who support its implementation. The paper enhances the understanding of the meaning of knowledge management in the context of healthcare organisations. The paper further provides insights into contextual factors that influence the success of knowledge management initiatives. Copyright © 2010 John Wiley & Sons, Ltd.
Knowledge management opportunity space identification strategy
Authors: Barcelo Valenzuela Mario , Sanchez Schmitz Gerardo , Perez Soltero Alonso , Romero Dessens Luis Felipe , Martin Rubio Fernando , Palma Jose 
Published: July 2010

AbstractThis paper proposes that in contemporary organizations it is very important to have an analysis strategy that relates people, processes, technologies, and the key Knowledge Management (KM) elements involved before a KM project is initiated. This strategy is essential to determine the enterprise KM state of the art and its key processes identifying any company weakness and supporting the opportunity space identification. Copyright © 2010 John Wiley & Sons, Ltd.
Knowledge sharing and decision making in the peace corps
Authors: Gilbert Engels , Morabito Joseph , Stohr Edward A. 
Published: July 2010

AbstractThe Peace Corps has over 7,800 volunteers serving in 70 countries. These volunteers bring a broad array of skills and experiences to their posts and they acquire valuable additional knowledge on the job—knowledge that is often lost when a volunteer retires after the customary two years of service. While the Peace Corps is aware of the value of this knowledge and attempts to create conditions in which it can be shared, a case study conducted by one of the authors found that there currently is no formal strategy to manage the flow of information and knowledge between different members of the organization. This is unfortunate since the ability to effectively capture and share information and knowledge could significantly ease the jobs of volunteers, increase their productivity, and improve morale. We develop a framework for knowledge management in a volunteer organization such as the Peace Corps where quick personnel turnover hampers traditional approaches to knowledge management. We articulate a set of computer and non‐computer‐based mechanisms in terms of procedures, policies, and IT tools to capture, share and transform data and information into usable knowledge. We conclude by proposing a knowledge management system based on these prescriptions that could be used in the Peace Corps or other similar, largely volunteer, organizations with a rapid turnover of personnel.Disclaimer:The Peace Corps had no connection with this project. The views in this report reflect only the personal views of the authors, and do not in any way describe or reflect the official views or position of the Peace Corps. Copyright © 2010 John Wiley & Sons, Ltd.
Beneficial Effect of Compatibilization on the Aging of Cellulose‐Reinforced Biopolymer Blends
Authors: Bessadok Atef , Belgacem Mohamed Naceur , Dufresne Alain , Bras Julien 
Published: July 2010

AbstractThe effect of aging on the thermo‐mechanical properties of new biocomposite materials obtained from renewable resources is studied. Cellulose was used as the reinforcing phase and the matrix was composed of a blend of two biopolymers (PEM and PLLA) in order to have a good compromise between stiffness and flexibility. Two grafting agents were used to compatibilize the filler with the matrix. The ensuing materials were then aged at 35 °C and 80% relative humidity during 45 days. Thermal and dynamic mechanical properties of the blends and composites were measured before and after aging. Important variations of crystallinity were observed and results show that grafting allowed obtaining high‐performance composites even after aging.magnified image
Comparison of mechanomyographic sensors during incremental cycle ergometry for the quadriceps femoris
Authors: Malek Moh H. , Coburn Jared W. , York Rene , Ng Jason , Rana Sharon R. 
Published: July 2010

AbstractThe purpose of this study was to examine the mechanomyographic (MMG) amplitude and mean power frequency (MPF) versus power output relationships for the vastus lateralis and rectus femoris muscles during incremental cycle ergometry between the piezoelectric contact sensor (HP) and the accelerometer (ACC) sensor. Nine men performed an incremental cycle ergometry test to voluntary exhaustion. Polynomial regression analyses on a subject‐by‐subject basis indicated that the relationship between the normalized MMG amplitude versus normalized power output was best fit with either a linear, quadratic, or cubic model. These patterns were consistent between sensors for each muscle for each subject. No consistent relationship was found for MMG MPF within subjects and between muscle groups. In addition, there were no significant sensor × power output interactions for normalized MMG amplitude or MPF. These results suggest that, for cycle ergometry, the HP and ACC sensors provide similar information for the interpretation of motor control strategies during continuous exercise. Muscle Nerve, 2010
An adaptive procedure for routine measurement of light‐touch sensitivity threshold
Authors: Berquin Anne D. , Lijesevic Valéria , Blond Serge , Plaghki Léon 
Published: July 2010

AbstractQuantitative sensory testing with Semmes–Weinstein monofilaments suffers from several pitfalls. Our aims were to assess the reliability of these filaments for touch–pressure threshold detection, develop and validate a rapid and accurate procedure for measurements at the bedside, and establish normative data. After calibration of the monofilaments, an adaptive staircase algorithm was validated and used to establish normative data in healthy subjects. Calibration showed significant differences between manufacturer‐ and investigator‐produced data. The relative humidity significantly affected the force exerted by the filaments. The adaptive procedure showed good accuracy and substantial time‐saving. Touch–pressure thresholds showed significant gender differences (mean ± 2 SD for females/males: 2.82–12.3/3.09–17.78 g/mm2). The influence of body site and age is small. Accurate use of Semmes–Weinstein monofilaments requires prior calibration, correction for humidity, and use of a validated procedure. In this study we provide normative data that can be used with our algorithm. Muscle Nerve, 2010