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Sample records for chemotactic factors

  1. Radioassay of granulocyte chemotaxis. Studies of human granulocytes and chemotactic factors. [/sup 51/Cr tracer technique

    Energy Technology Data Exchange (ETDEWEB)

    Gallin, J.I.

    1974-01-01

    The above studies demonstrate that the /sup 51/Cr radiolabel chemotactic assay is a relatively simple and objective means for studying leukocyte chemotaxis in both normal and pathological conditions. Application of this method to studies of normal human chemotaxis revealed a relatively narrow range of normal and little day-to-day variability. Analysis of this variability revealed that there is more variability among the response of different granulocytes to a constant chemotactic stimulus than among the chemotactic activity of different sera to a single cell source. Utilizing the /sup 51/Cr radioassay, the abnormal granulocyte chemotactic behavior reported in Chediak-Higashi syndrome and a patient with recurrent pyogenic infections and mucocutaneous candidiasis has been confirmed. The /sup 51/Cr chemotactic assay has also been used to assess the generation of chemotactic activity from human serum and plasma. The in vitro generation of two distinct chemotactic factors were examined; the complement product (C5a) and kallikrein, an enzyme of the kinin-generating pathway. Kinetic analysis of complement-related chemotactic factor formation, utilizing immune complexes or endotoxin to activate normal sera in the presence or absence of EGTA as well as kinetic analysis of activation of C2-deficient human serum, provided an easy means of distinguishing the classical (antibody-mediated) complement pathway from the alternate pathway. Such kinetic analysis is necessary to detect clinically important abnormalities since, after 60 min of generation time, normal chemotactic activity may be present despite complete absence or inhibition of one complement pathway. The chemotactic factor generated by either pathway of complement activation appears to be predominately attributable to C5a.

  2. Corneal organ cultures in tyrosinemia release chemotactic factors.

    Science.gov (United States)

    Lohr, K M; Hyndiuk, R A; Hatchell, D L; Kurth, C E

    1985-05-01

    Corneal inflammation with subsequent scarring and blindness occurs in the inherited human metabolic disease tyrosinemia type II, yet putative inflammatory mediators in this disorder and in the avascular cornea in general are poorly defined. In a Tyr-fed rat model of tyrosinemia type II, intracellular crystals, presumably Tyr, are hypothesized to be responsible for the increased lysosomal activity observed in corneal epithelial lesions. Because polymorphonuclear leukocytes (PMNs) are seen only at the site of these lesions, we used this model to study humoral mediators released from Tyr-fed rat corneal organ cultures. Only Tyr-fed rats developed stromal edema and linear granular opacities in gray edematous corneal epithelium, compatible with a noninfectious keratitis. Electron micrographs confirmed epithelial edema and showed focal epithelial necrosis with PMN invasion of the stroma. Only Tyr-fed rat corneal culture supernatants contained chemotactic activity that was heat labile and moderately trypsin sensitive. Four peaks with varying amounts of chemotactic activity were found on Sephadex G-75 chromatography. Although the identity of these peaks of activity has not yet been established, we suggest that they may be responsible for the PMN infiltration observed in this model of corneal inflammation.

  3. DETECTION OF A NEUTROPHIL CHEMOTACTIC FACTOR IN JAPANESE ENCEPHALITIS PATIENTS

    Directory of Open Access Journals (Sweden)

    Aditi Singh

    2012-12-01

    Full Text Available Japanese encephalitis (JE one of the most common cause of acute encephalitis in tropical regions, has generated much public anxiety in India. An early influx of macrophages followed by neutrophils at the site of injury in different organs in humans and mice has previously been reported. It correlated with production of a neutrophil chemotactic protein derived from macrophages. In the present study out of a total of 324 acute encephalitic patients, admitted in Gandhi memorial and associated hospitals, Lucknow, 121 patients with one or more indicators of JE virus infection were included. Significant pleocytosis (mean TLC value of 126+52 cells / mm3 in CSF and leucocytosis (>11,000 cells/mm3 in peripheral blood was observed at the time of admission. The leucocytosis increased significantly during second week in 67% of patients. The peripheral blood mononuclear cells culture done on alternate days was tested for chemotactic activity (hMDF, which was observed to be highest in second week of illness. The direct detection of hMDF in circulation by dot blot was positive in 92% of acute serum samples, with negligible (12.5% reactivity for convalescent sera. A correlation between the hMDF levels and severity of illness has also been observed.

  4. Interleukin-8 is a major neutrophil chemotactic factor derived from cultured human gingival fibroblasts stimulated with interleukin-1 beta or tumor necrosis factor alpha.

    OpenAIRE

    Takashiba, S; Takigawa, M; Takahashi, K; Myokai, F; Nishimura, F.; Chihara, T.; Kurihara, H.; Nomura, Y.; Murayama, Y.

    1992-01-01

    Inflammatory mediators produced by cells in the gingiva have been implicated in the initiation and progression of periodontal disease, a common infectious disease. In this study, we examined the biological activity of neutrophil chemotactic factors and the kinetics of expression of interleukin-8 (IL-8) mRNA derived from normal gingival fibroblasts in response to inflammatory mediators in an in vitro model. Gingival fibroblasts stimulated by either recombinant human interleukin-1 beta or recom...

  5. Plasma Levels of Monocyte Chemotactic Protein 3 and Beta-Nerve Growth Factor Increase with Amnestic Mild Cognitive Impairment

    Institute of Scientific and Technical Information of China (English)

    Kang Soo Lee; Ji Hyung Chung; Kyung Hye Lee; Min-Jeong Shin; Byoung Hoon Oh; Soo Hyung Lee; Chang Hyung Hong

    2009-01-01

    A number of studies have investigated peripheral inflammatory indices, including plasma cytokines and related molecules according to subtypes of dementia, but not in mild cognitive impairment (MCI). In this study, we used multiplex cytokine assay to assess the plasma levels of 22 cytokines in patients with MCI subtyped as amnestic and non-amnestic, according to cognitive features. When comparing the levels of plasma growth factors, chemokines and cytokines, plasma levels of monocyte chemotactic protein 3 (MCP-3), and beta-nerve growth factor (β-NGF) in these two groups, they were found to be significantly higher in amnestic MCI patients than in non-amnestic MCI patients, after adjusting for age and gender. This suggests that plasma MCP-3 and β-NGF may be useful in differentiating subtypes of MCI. Cellular & Molecular Immunology.

  6. Beta-adrenergic receptor agonists induce the release of granulocyte chemotactic protein-2, oncostatin M, and vascular endothelial growth factor from macrophages

    NARCIS (Netherlands)

    Verhoeckx, K.C.M.; Doornbos, R.P.; Witkamp, R.F.; Greef, de J.; Rodenburg, R.J.T.

    2006-01-01

    Vascular endothelial growth factor (VEGF), oncostatin M (OSM), and granulocyte chemotactic protein-2 (GCP-2/CXCL6) are up-regulated in U937 macrophages and peripheral blood macrophages exposed to LPS, beta-adrenergic receptor (ß2-AR) agonists (e.g. zilpaterol, and clenbuterol) and some other agents

  7. Beta-adrenergic receptor agonists induce the release of granulocyte chemotactic protein-2, oncostatin M, and vascular endothelial growth factor from macrophages

    NARCIS (Netherlands)

    Verhoeckx, K.C.; Doornbos, R.P.; Witkamp, R.F.; Greef, J. van der; Rodenburg, R.J.T.

    2006-01-01

    Vascular endothelial growth factor (VEGF), oncostatin M (OSM), and granulocyte chemotactic protein-2 (GCP-2/CXCL6) are up-regulated in U937 macrophages and peripheral blood macrophages exposed to LPS, beta-adrenergic receptor (beta2-AR) agonists (e.g. zilpaterol, and clenbuterol) and some other agen

  8. Beta-adrenergic receptor agonists induce the release of granulocyte chemotactic protein-2, oncostatin M, and vascular endothelial growth factor from macrophages

    NARCIS (Netherlands)

    Verhoeckx, K.C.M.; Doornbos, R.P.; Witkamp, R.F.; Greef, J. van der; Rodenburg, R.J.T.

    2006-01-01

    Vascular endothelial growth factor (VEGF), oncostatin M (OSM), and granulocyte chemotactic protein-2 (GCP-2/CXCL6) are up-regulated in U937 macrophages and peripheral blood macrophages exposed to LPS, beta-adrenergic receptor (β2-AR) agonists (e.g. zilpaterol, and clenbuterol) and some other agents

  9. Does it make sense to target one tumor cell chemotactic factor or its receptor when several chemotactic axes are involved in metastasis of the same cancer?

    Science.gov (United States)

    Ratajczak, Mariusz Z; Suszynska, Malwina; Kucia, Magda

    2016-12-01

    The major problem with cancer progression and anti-cancer therapy is the inherent ability of cancer cells to migrate and establish distant metastases. This ability to metastasize correlates with the presence in a growing tumor of cells with a more malignant phenotype, which express certain cancer stem cell markers. The propensity of malignant cells to migrate and their resistance to radio-chemotherapy somewhat mimics the properties of normal developmentally early stem cells that migrate during organogenesis in the developing embryo. In the past, several factors, including cell migration-promoting cytokines, chemokines, growth factors, bioactive lipids, extracellular nucleotides, and even H(+) ions, were found to influence the metastasis of cancer cells. This plethora of pro-migratory factors demonstrates the existence of significant redundancy in the chemoattractants for cancer cells. In spite of this obvious fact, significant research effort has been dedicated to demonstrating the crucial involvement of particular pro-metastatic factor-receptor axes and the development of new drugs targeting one receptor or one chemoattractant. Based on our own experience working with a model of metastatic rhabdomyosarcoma as well as the work of others, in this review we conclude that targeting a single receptor-ligand pro-metastatic axis will not effectively prevent metastasis and that we should seek other more effective therapeutic options. PMID:27510263

  10. Delivery of platelet-derived growth factor as a chemotactic factor for mesenchymal stem cells by bone-mimetic electrospun scaffolds.

    Directory of Open Access Journals (Sweden)

    Matthew C Phipps

    Full Text Available The recruitment of mesenchymal stem cells (MSCs is a vital step in the bone healing process, and hence the functionalization of osteogenic biomaterials with chemotactic factors constitutes an important effort in the tissue engineering field. Previously we determined that bone-mimetic electrospun scaffolds composed of polycaprolactone, collagen I and nanohydroxyapatite (PCL/col/HA supported greater MSC adhesion, proliferation and activation of integrin-related signaling cascades than scaffolds composed of PCL or collagen I alone. In the current study we investigated the capacity of bone-mimetic scaffolds to serve as carriers for delivery of an MSC chemotactic factor. In initial studies, we compared MSC chemotaxis toward a variety of molecules including PDGF-AB, PDGF-BB, BMP2, and a mixture of the chemokines SDF-1α, CXCL16, MIP-1α, MIP-1β, and RANTES. Transwell migration assays indicated that, of these factors, PDGF-BB was the most effective in stimulating MSC migration. We next evaluated the capacity of PCL/col/HA scaffolds, compared with PCL scaffolds, to adsorb and release PDGF-BB. We found that significantly more PDGF- BB was adsorbed to, and subsequently released from, PCL/col/HA scaffolds, with sustained release extending over an 8-week interval. The PDGF-BB released was chemotactically active in transwell migration assays, indicating that bioactivity was not diminished by adsorption to the biomaterial. Complementing these studies, we developed a new type of migration assay in which the PDGF-BB-coated bone-mimetic substrates were placed 1.5 cm away from the cell migration front. These experiments confirmed the ability of PDGF-BB-coated PCL/col/HA scaffolds to induce significant MSC chemotaxis under more stringent conditions than standard types of migration assays. Our collective results substantiate the efficacy of PDGF-BB in stimulating MSC recruitment, and further show that the incorporation of native bone molecules, collagen I and nano

  11. Effect of a short-term diet and exercise intervention on oxidative stress, inflammation, MMP-9, and monocyte chemotactic activity in men with metabolic syndrome factors.

    Science.gov (United States)

    Roberts, Christian K; Won, Dean; Pruthi, Sandeep; Kurtovic, Silvia; Sindhu, Ram K; Vaziri, Nosratola D; Barnard, R James

    2006-05-01

    The present study was designed to examine the effects of lifestyle modification on key contributing factors to atherogenesis, including oxidative stress, inflammation, chemotaxis, and cell adhesion. Obese men (n = 31), 15 of whom had metabolic syndrome, were placed on a high-fiber, low-fat diet in a 3-wk residential program where food was provided ad libitum and daily aerobic exercise was performed. In each subject, pre- and postintervention fasting blood was drawn for circulating levels of serum lipids, glucose and insulin (for estimation of insulin sensitivity), oxidative stress-generating enzyme myeloperoxidase and marker 8-isoprostaglandin F2alpha, the inflammatory protein C-reactive protein, soluble ICAM-1 as an indicator of endothelial activation, sP-selectin as a marker of platelet activation, the chemokine macrophage inflammatory protein-1alpha, and total matrix metalloproteinase-9. Using subject sera and human aortic endothelial cell culture systems, we measured VCAM-1 cell surface abundance and monocyte chemotactic protein-1, nitric oxide, superoxide, and hydrogen peroxide production in vitro by fluorometric detection. Also determined in vitro was serum-induced, monocyte adhesion and monocyte chemotactic activity. After 3 wk, significant reductions (P fasting glucose, insulin, homeostasis model assessment for insulin resistance, myeloperoxidase, 8-isoprostaglandin F2alpha, C-reactive protein, soluble ICAM-1, soluble P-selectin, macrophage inflammatory protein-1alpha, and matrix metalloproteinase-9 were noted. In vitro, serum-stimulated cellular VCAM-1 expression, monocyte chemotactic protein-1 production, and fluorometric detection of superoxide and hydrogen peroxide production decreased, whereas a concomitant increase in NO production was noted (all P < 0.01). Additionally, both monocyte adhesion (P < 0.05) and MCA (P < 0.01) decreased. Nine of 15 were no longer positive for metabolic syndrome postintervention. Intensive lifestyle modification may

  12. Stromal-derived factor-1α/CXCL12-CXCR4 chemotactic pathway promotes perineural invasion in pancreatic cancer.

    Science.gov (United States)

    Xu, Qinhong; Wang, Zheng; Chen, Xin; Duan, Wanxing; Lei, Jianjun; Zong, Liang; Li, Xuqi; Sheng, Liang; Ma, Jiguang; Han, Liang; Li, Wei; Zhang, Lun; Guo, Kun; Ma, Zhenhua; Wu, Zheng; Wu, Erxi; Ma, Qingyong

    2015-03-10

    Perineural invasion (PNI) is considered as an alternative route for the metastatic spread of pancreatic cancer cells; however, the molecular changes leading to PNI are still poorly understood. In this study, we show that the CXCL12/CXCR4 axis plays a pivotal role in the neurotropism of pancreatic cancer cells to local peripheral nerves. Immunohistochemical staining results revealed that CXCR4 elevation correlated with PNI in 78 pancreatic cancer samples. Both in vitro and in vivo PNI models were applied to investigate the function of the CXCL12/CXCR4 signaling in PNI progression and pathogenesis. The results showed that the activation of the CXCL12/CXCR4 axis significantly increased pancreatic cancer cells invasion and promoted the outgrowth of the dorsal root ganglia. CXCL12 derived from the peripheral nerves stimulated the invasion and chemotactic migration of CXCR4-positive cancer cells in a paracrine manner, eventually leading to PNI. In vivo analyses revealed that the abrogation of the activated signaling inhibited tumor growth and invasion of the sciatic nerve toward the spinal cord. These data indicate that the CXCL12/CXCR4 axis may be a novel therapeutic target to prevent the perineural dissemination of pancreatic cancer.

  13. Gradient sensing in defined chemotactic fields

    OpenAIRE

    Skoge, Monica; Adler, Micha; Groisman, Alex; Levine, Herbert; Loomis, William F.; Rappel, Wouter-Jan

    2010-01-01

    Cells respond to a variety of secreted molecules by modifying their physiology, growth patterns, and behavior. Motile bacteria and eukaryotic cells can sense extracellular chemoattractants and chemorepellents and alter their movement. In this way fibroblasts and leukocytes can find their ways to sites of injury and cancer cells can home in on sites that are releasing growth factors. Social amoebae such as Dictyostelium are chemotactic to cAMP which they secrete several hours after they have i...

  14. Psoriasin: a novel chemotactic protein

    DEFF Research Database (Denmark)

    Jinquan, T; Vorum, H; Larsen, C G;

    1996-01-01

    inflammatory protein for CD4+ T lymphocytes and neutrophils at concentrations of about 10(-11) M. Psoriasin is not structurally related to the alpha or the beta chemokine subfamilies or to lymphotactin, a member of a newly described class of chemokines. Thus, we have observed a chemotactic protein outside...... the chemokine subfamilies that could be an important new inflammatory mediator. Udgivelsesdato: 1996-Jul...

  15. Monocyte chemotactic protein-1 gene polymorphism and spontaneous bacterial peritonitis

    Institute of Scientific and Technical Information of China (English)

    Levent; Filik

    2010-01-01

    I read with great interest the article by Gbele et al published in issue 44 of World J Gastroenterol 2009.The results of their study indicate that-2518 Monocyte chemotactic protein-1(MCP-1)genotype AA is a risk factor for spontaneous bacterial peritonitis in patients with alcoholic cirrhosis.However,there are some items that need to be discussed.

  16. Correlation of pathogenesis of Toll-like receptor and chemotactic factor with lyme arthritis%Toll样受体和趋化因子与莱姆关节炎发病的相关性

    Institute of Scientific and Technical Information of China (English)

    汪玉娇; 宝福凯; 柳爱华

    2012-01-01

    莱姆病是一种由伯氏疏螺旋体引起,经蜱传播的自然疫源性疾病,也是一种人兽共患病,莱姆关节炎是莱姆病的晚期临床表现,严重者可终生致残,严重影响了人们的健康和生活质量,目前,对莱姆关节炎的致病机制尚不清楚,国内外已经取得了一系列进展,但有待进一步研究.现就Toll样受体和趋化因子与莱姆关节炎发病关系的研究做一综述.%Lyme disease, which is caused by Borrelia burgdorferi and spread by ticks, is a kind of natural foci disease and parasitic zoonoses. Lyme Arthritis is the late clinical manifestation of Lyme disease, it can make patients in lifelong disability in some severe cases and seriously affect healthy and life quality of patients. Until now, We still don't understand the pathogenic mechanism of Lyme Arthritis clearly, although there is a serious progress about it at home and aboard, further study on it is necessary. This article is intent to summarize the researches on relationship between Toll-like receptor, chemotactic factor and Lyme Arthritis.

  17. Gradient sensing in defined chemotactic fields.

    Science.gov (United States)

    Skoge, Monica; Adler, Micha; Groisman, Alex; Levine, Herbert; Loomis, William F; Rappel, Wouter-Jan

    2010-11-01

    Cells respond to a variety of secreted molecules by modifying their physiology, growth patterns, and behavior. Motile bacteria and eukaryotic cells can sense extracellular chemoattractants and chemorepellents and alter their movement. In this way fibroblasts and leukocytes can find their way to sites of injury and cancer cells can home in on sites that are releasing growth factors. Social amoebae such as Dictyostelium are chemotactic to cAMP which they secrete several hours after they have initiated development. These eukaryotic cells are known to be able to sense extremely shallow gradients but the processes underlying their exquisite sensitivity are still largely unknown. In this study we determine the responses of developed cells of Dictyostelium discoideum to stable linear gradients of cAMP of varying steepness generated in 2 μm deep gradient chambers of microfluidic devices. The gradients are generated by molecular diffusion between two 80 μm deep flow-through channels, one of which is perfused with a solution of cAMP and the other with buffer, serving as continuously replenished source and sink. These low ceiling gradient chambers constrained the cells in the vertical dimension, facilitating confocal imaging, such that subcellular localization of fluorescently tagged proteins could be followed for up to 30 min without noticeable phototoxicity. Chemotactic cells enter these low ceiling chambers by flattening and elongating and then move almost as rapidly as unconstrained cells. By following the localization of activated Ras (RasGTP) using a Ras Binding Domain fused to Green Fluorescent Protein (RBD-GFP), we observed the rapid appearance of membrane associated patches at the tips of pseudopods. These patches remained associated with pseudopods while they continued to extend but were rapidly disassembled when pseudopods stalled and the cell moved past them. Likewise, fluorescence associated with localized RasGTP rapidly disappeared when the gradient was turned

  18. Lower concentrations of chemotactic cytokines and soluble innate factors in the lower female genital tract associated with the use of injectable hormonal contraceptive.

    Science.gov (United States)

    Ngcapu, Sinaye; Masson, Lindi; Sibeko, Sengeziwe; Werner, Lise; McKinnon, Lyle R; Mlisana, Koleka; Shey, Muki; Samsunder, Natasha; Karim, Salim Abdool; Karim, Quarraisha Abdool; Passmore, Jo-Ann S

    2015-08-01

    Progesterone-based injectable hormonal contraceptives (HCs) potentially modulate genital barrier integrity and regulate the innate immune environment in the female genital tract, thereby enhancing the risk of STIs or HIV infection. We investigated the effects of injectable HC use on concentrations of inflammatory cytokines and other soluble factors associated with genital epithelial repair and integrity. The concentrations of 42 inflammatory, regulatory, adaptive growth factors and hematopoietic cytokines, five matrix metalloproteinases (MMPs), and four tissue inhibitors of metalloproteinases (TIMPs) were measured in cervicovaginal lavages (CVLs) from 64 HIV-negative women using injectable HCs and 64 control women not using any HCs, in a matched case-control study. There were no differences between groups in the prevalence of bacterial vaginosis (BV; Nugent score ≥7), or common sexually transmitted infections (STIs). In multivariate analyses adjusting for condom use, sex work status, marital status, BV and STIs, median concentrations of chemokines (eotaxin, MCP-1, MDC), adaptive cytokines (IL-15), growth factors (PDGF-AA) and a metalloproteinase (TIMP-2) were significantly lower in CVLs from women using injectable HCs than controls. In addition, the pro-inflammatory cytokine IL-12p40 and the chemokine fractalkine were less likely to have detectable levels in women using injectable HCs compared with those not using HCs. We conclude that injectable HC use was broadly associated with an immunosuppressive female genital tract innate immune profile. While the relationship between injectable HC use and STI or HIV risk is yet to be resolved, our data suggest that the effects of injectable HCs were similar in STI-positive and STI-negative participants.

  19. Jeans type analysis of chemotactic collapse

    CERN Document Server

    Chavanis, Pierre-Henri

    2007-01-01

    We perform a linear dynamical stability analysis of a general hydrodynamic model of chemotactic aggregation [Chavanis & Sire, Physica A, in press (2007)]. Specifically, we study the stability of an infinite and homogeneous distribution of cells against ``chemotactic collapse''. We discuss the analogy between the chemotactic collapse of biological populations and the gravitational collapse (Jeans instability) of self-gravitating systems. Our hydrodynamic model involves a pressure force which can take into account several effects like anomalous diffusion or the fact that the organisms cannot interpenetrate. We also take into account the degradation of the chemical which leads to a shielding of the interaction like for a Yukawa potential. Finally, our hydrodynamic model involves a friction force which quantifies the importance of inertial effects. In the strong friction limit, we obtain a generalized Keller-Segel model similar to the generalized Smoluchowski-Poisson system describing self-gravitating Langevi...

  20. Nicotine is Chemotactic for Neutrophils and Enhances Neutrophil Responsiveness to Chemotactic Peptides

    Science.gov (United States)

    Totti, Noel; McCusker, Kevin T.; Campbell, Edward J.; Griffin, Gail L.; Senior, Robert M.

    1984-01-01

    Neutrophils contribute to chronic bronchitis and pulmonary emphysema associated with cigarette smoking. Nicotine was found to be chemotactic for human neutrophils but not monocytes, with a peak activity at ~ 31 micromolar. In lower concentrations (comparable to those in smokers' plasma), nicotine enhanced the response of neutrophils to two chemotactic peptides. In contrast to most other chemoattractants for neutrophils, however, nicotine did not affect degranulation or superoxide production. Nicotine thus may promote inflammation and consequent lung injury in smokers.

  1. Kinetic and hydrodynamic models of chemotactic aggregation

    CERN Document Server

    Chavanis, Pierre-Henri

    2007-01-01

    We derive general kinetic and hydrodynamic models of chemotactic aggregation that describe certain features of the morphogenesis of biological colonies (like bacteria, amoebae, endothelial cells or social insects). Starting from a stochastic model defined in terms of N coupled Langevin equations, we derive a nonlinear mean field Fokker-Planck equation governing the evolution of the distribution function of the system in phase space. By taking the successive moments of this kinetic equation and using a local thermodynamic equilibrium condition, we derive a set of hydrodynamic equations involving a damping term. In the limit of small frictions, we obtain a hyperbolic model describing the formation of network patterns (filaments) and in the limit of strong frictions we obtain a parabolic model which is a generalization of the standard Keller-Segel model describing the formation of clusters (clumps). Our approach connects and generalizes several models introduced in the chemotactic literature. We discuss the anal...

  2. Jeans type analysis of chemotactic collapse

    Science.gov (United States)

    Chavanis, Pierre-Henri; Sire, Clément

    2008-07-01

    We perform a linear dynamical stability analysis of a general hydrodynamic model of chemotactic aggregation [P.H. Chavanis, C. Sire, Physica A 384 (2007) 199]. Specifically, we study the stability of an infinite and homogeneous distribution of cells against “chemotactic collapse”. We discuss the analogy between the chemotactic collapse of biological populations and the gravitational collapse (Jeans instability) of self-gravitating systems. Our hydrodynamic model involves a pressure force which can take into account several effects like anomalous diffusion or the fact that the organisms cannot interpenetrate. We also take into account the degradation of the chemical which leads to a shielding of the interaction like for a Yukawa potential. Finally, our hydrodynamic model involves a friction force which quantifies the importance of inertial effects. In the strong friction limit, we obtain a generalized Keller-Segel model similar to the generalized Smoluchowski-Poisson system describing self-gravitating Langevin particles. For small frictions, we obtain a hydrodynamic model of chemotaxis similar to the Euler-Poisson system describing a self-gravitating barotropic gas. We show that an infinite and homogeneous distribution of cells is unstable against chemotactic collapse when the “velocity of sound” in the medium is smaller than a critical value. We study in detail the linear development of the instability and determine the range of unstable wavelengths, the growth rate of unstable modes and the damping rate, or the pulsation frequency, of the stable modes as a function of the friction parameter and shielding length. For specific equations of state, we express the stability criterion in terms of cell density.

  3. Identification of a chemotactic sensitivity in a coupled system

    CERN Document Server

    Fister, K Renee

    2007-01-01

    Chemotaxis is the process by which cells behave in a way that follows the chemical gradient. Applications to bacteria growth, tissue inflammation, and vascular tumors provide a focus on optimization strategies. Experiments can characterize the form of possible chemotactic sensitivities. This paper addresses the recovery of the chemotactic sensitivity from these experiments while allowing for nonlinear dependence of the parameter on the state variables. The existence of solutions to the forward problem is analyzed. The identification of a chemotactic parameter is determined by inverse problem techniques. Tikhonov regularization is investigated and appropriate convergence results are obtained. Numerical results of concentration dependent chemotactic terms are explored.

  4. Dynamics of Chemotactic Droplets in Salt Concentration Gradients

    DEFF Research Database (Denmark)

    Cejkova, J.; Novak, M.; Stepanek, F.;

    2014-01-01

    The chemotactic movement of decanol droplets in aqueous solutions of sodium decanoate in response to concentration gradients of NaCl has been investigated. Key parameters of the chemotactic response, namely the induction time and the migration velocity, have been evaluated as a function of the so...

  5. Chemotactic selection of pollutant degrading soil bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Hazen, T.C.

    1991-03-04

    A method is described for identifying soil microbial strains which may be bacterial degraders of pollutants. This method includes: Placing a concentration of a pollutant in a substantially closed container; placing the container in a sample of soil for a period of time ranging from one minute to several hours; retrieving the container and collecting its contents; microscopically determining the identity of the bacteria present. Different concentrations of the pollutant can be used to determine which bacteria respond to each concentration. The method can be used for characterizing a polluted site or for looking for naturally occurring biological degraders of the pollutant. Then bacteria identified as degraders of the pollutant and as chemotactically attracted to the pollutant are used to innoculate contaminated soil. To enhance the effect of the bacteria on the pollutant, nutrients are cyclicly provided to the bacteria then withheld to alternately build up the size of the bacterial colony or community and then allow it to degrade the pollutant.

  6. An enzyme immunoassay for detection of Japanese encephalitis virus-induced chemotactic cytokine

    Indian Academy of Sciences (India)

    Aditi Singh; Rajesh Kulshreshtha; Asha Mathur

    2000-03-01

    Japanese encephalitis virus (JEV) induces human peripheral blood monocytes to secrete a chemotactic cytokine [human macrophage-derived factor (hMDF)] which causes chemotaxis of neutrophils. The only known assay for hMDF cannot quantify its level in samples, so an enzyme immunoassay has been standardized for detection of hMDF and hMDF-specific antibodies in test samples. The reported enzyme linked immunosorbent assay (ELISA) was found to be sensitive (89%), specific (91%), accurate (92·2%) and reproducible and was able to detect a minimum concentration of 23 ng hMDF/ml in test samples. The chemotactic factor could be detected in JEV inoculated mouse sera and JEV infected culture fluids. Significant finding of the test was the detection of hMDF in sera of human cases of JE.

  7. Polymorphonuclear neutrophil granulocyte chemotactic hyperresponsiveness in a case of canine acromegaly.

    Science.gov (United States)

    Jensen, A L; Thomsen, M K; Aaes, H; Andreasen, M; Søndergaard, J

    1993-08-01

    Growth hormone (GH) has recently been shown to affect polymorphonuclear neutrophil granulocyte (PMN) function and to be secreted by mononuclear cells, indicating that the hormone may be active in an immunophysiologic network, acting as an endo- or paracrine priming agent. The purpose of the present study was to evaluate the chemotactic responsiveness of canine peripheral PMN in a dog with acromegaly, caused by spontaneous, progesterone-induced hypersecretion of GH and, secondary to this, a seven-fold increase in insulin-like growth factor I (IGF-I). The chemotactic responsiveness towards zymosan-activated serum (ZAS) and leukotriene B4 (LTB4) was evaluated at a time when the dog suffered from acromegaly and again 57 days after corrective surgery (ovariohysterectomy). The experiments showed that PMN from the patient exhibited enhanced chemotactic migration that appeared to be associated with the hypersomatotropic condition as judged from the reversibility of the phenomenon. The glucose intolerance and elevated serum alkaline phosphatase that were observed in the acromegalic dog were also shown to be reversible following surgery.

  8. Automated Chemotactic Sorting and Single-cell Cultivation of Microbes using Droplet Microfluidics

    Science.gov (United States)

    Dong, Libing; Chen, Dong-Wei; Liu, Shuang-Jiang; Du, Wenbin

    2016-04-01

    We report a microfluidic device for automated sorting and cultivation of chemotactic microbes from pure cultures or mixtures. The device consists of two parts: in the first part, a concentration gradient of the chemoeffector was built across the channel for inducing chemotaxis of motile cells; in the second part, chemotactic cells from the sample were separated, and mixed with culture media to form nanoliter droplets for encapsulation, cultivation, enumeration, and recovery of single cells. Chemotactic responses were assessed by imaging and statistical analysis of droplets based on Poisson distribution. An automated procedure was developed for rapid enumeration of droplets with cell growth, following with scale-up cultivation on agar plates. The performance of the device was evaluated by the chemotaxis assays of Escherichia coli (E. coli) RP437 and E. coli RP1616. Moreover, enrichment and isolation of non-labelled Comamonas testosteroni CNB-1 from its 1:10 mixture with E. coli RP437 was demonstrated. The enrichment factor reached 36.7 for CNB-1, based on its distinctive chemotaxis toward 4-hydroxybenzoic acid. We believe that this device can be widely used in chemotaxis studies without necessarily relying on fluorescent labelling, and isolation of functional microbial species from various environments.

  9. On a competitive system under chemotactic effects with non-local terms

    International Nuclear Information System (INIS)

    In this paper, we study a system of partial differential equations describing the evolution of a population under chemotactic effects with non-local reaction terms. We consider an external application of chemoattractant in the system and study the cases of one and two populations in competition. By introducing global competitive/cooperative factors in terms of the total mass of the populations, we obtain, for a range of parameters, that any solution with positive and bounded initial data converges to a spatially homogeneous state with positive components. The proofs rely on the maximum principle for spatially homogeneous sub- and super-solutions. (paper)

  10. MiR-124 suppresses the chemotactic migration of rat mesenchymal stem cells toward HGF by downregulating Wnt/β-catenin signaling.

    Science.gov (United States)

    Yue, Qing; Zhang, Yu; Li, Xianyang; He, Lihong; Hu, Ya'nan; Wang, Xianyao; Xu, Xiaojing; Shen, Yixin; Zhang, Huanxiang

    2016-09-01

    Mesenchymal stem cells (MSCs) exhibit the potential to repair a wide variety of injured adult tissues. The migration capability of MSCs is an important determinant of the efficiency of MSC transplant therapy. MicroRNAs (miRNAs) are increasingly implicated in regulating the migration of MSCs. Herein, we show that the expression of miR-124 was downregulated in rat MSCs (rMSCs) treated with hepatocyte growth factor (HGF). Overexpression of miR-124 significantly reduced the chemotactic migration of rMSCs toward HGF, while inhibition of endogenous miR-124 promoted the chemotactic migration. A further study revealed that miR-124 directly targeted FZD4 and LRP6, which encode a receptor and co-receptor of the Wnt/β-catenin signaling pathway, respectively, thus reducing the activity of this signaling. Consistently, activation of the Wnt/β-catenin signaling pathway by LiCl and ΔN89β-catenin rescued the inhibitory effect of miR-124 on the chemotactic migration of rMSCs toward HGF, while inhibition of Wnt/β-catenin signaling by FH535 abrogated the enhanced chemotactic response achieved by the miR-124 inhibitor. Collectively, our study demonstrates that miR-124 downregulates Wnt/β-catenin signaling via targeting FZD4 and LRP6 and thus suppresses the chemotactic migration of rMSCs toward HGF.

  11. Stability and dynamics of anisotropically-tumbling chemotactic swimmers

    CERN Document Server

    Lushi, Enkeleida

    2016-01-01

    Micro-swimmers such as bacteria E. coli are known to perform random walks known as run-and-tumbles to move up chemo-attractant gradients and as a result aggregate. It is also known that such micro-swimmers can self-organize into macroscopic patterns due to interactions with neighboring cells through the fluidic environment they live in. While the pattern formation resulting from chemotactic and hydrodynamic interactions separately and together have been previously investigated, the effect of the tumbling anisotropy in micro-swimmers has been unexplored. Here we show through linear analysis and full nonlinear simulations that the slight anisotropy in the individual swimmer tumbles can alter the collective pattern formation in non-trivial ways. We show that the tumbling anisotropy diminishes the magnitude of the chemotactic aggregates but may result in more such aggregation peaks.

  12. Maternal circulating leukocytes display early chemotactic responsiveness during late gestation

    Directory of Open Access Journals (Sweden)

    Gomez-Lopez Nardhy

    2013-01-01

    Full Text Available Abstract Background Parturition has been widely described as an immunological response; however, it is unknown how this is triggered. We hypothesized that an early event in parturition is an increased responsiveness of peripheral leukocytes to chemotactic stimuli expressed by reproductive tissues, and this precedes expression of tissue chemotactic activity, uterine activation and the systemic progesterone/estradiol shift. Methods Tissues and blood were collected from pregnant Long-Evans rats on gestational days (GD 17, 20 and 22 (term gestation. We employed a validated Boyden chamber assay, flow cytometry, quantitative real time-polymerase chain reaction, and enzyme-linked immunosorbent assays. Results We found that GD20 maternal peripheral leukocytes migrated more than those from GD17 when these were tested with GD22 uterus and cervix extracts. Leukocytes on GD20 also displayed a significant increase in chemokine (C-C motif ligand 2 (Ccl2 gene expression and this correlated with an increase in peripheral granulocyte proportions and a decrease in B cell and monocyte proportions. Tissue chemotactic activity and specific chemokines (CCL2, chemokine (C-X-C motif ligand 1/CXCL1, and CXCL10 were mostly unchanged from GD17 to GD20 and increased only on GD22. CXCL10 peaked on GD20 in cervical tissues. As expected, prostaglandin F2α receptor and oxytocin receptor gene expression increased dramatically between GD20 and 22. Progesterone concentrations fell and estradiol-17β concentrations increased in peripheral serum, cervical and uterine tissue extracts between GD20 and 22. Conclusion Maternal circulating leukocytes display early chemotactic responsiveness, which leads to their infiltration into the uterus where they may participate in the process of parturition.

  13. Down-regulation of the chemokine receptor CCR5 by activation of chemotactic formyl peptide receptor in human monocytes.

    Science.gov (United States)

    Shen, W; Li, B; Wetzel, M A; Rogers, T J; Henderson, E E; Su, S B; Gong, W; Le, Y; Sargeant, R; Dimitrov, D S; Oppenheim, J J; Wang, J M

    2000-10-15

    Interactions between cell surface receptors are important regulatory elements in the complex host responses to infections. In this study, it is shown that a classic chemotactic factor, the bacterial chemotactic peptide N-formyl-methionyl-leucylphenyl-alanine (fMLF), rapidly induced a protein-kinase-C-mediated serine phosphorylation and down-regulation of the chemokine receptor CCR5, which serves as a major human immunodeficiency virus (HIV)-1 coreceptor. The fMLF binding to its receptor, formyl peptide receptor (FPR), resulted in significant attenuation of cell responses to CCR5 ligands and in inhibition of HIV-1-envelope-glycoprotein-mediated fusion and infection of cells expressing CD4, CCR5, and FPR. The finding that the expression and function of CCR5 can be regulated by peptides that use an unrelated receptor may provide a novel approach to the design of anti-inflamatory and antiretroviral agents. (Blood. 2000;96:2887-2894)

  14. Spatial regulation of the cAMP-dependent protein kinase during chemotactic cell migration.

    Science.gov (United States)

    Howe, Alan K; Baldor, Linda C; Hogan, Brian P

    2005-10-01

    Historically, the cAMP-dependent protein kinase (PKA) has a paradoxical role in cell motility, having been shown to both facilitate and inhibit actin cytoskeletal dynamics and cell migration. In an effort to understand this dichotomy, we show here that PKA is regulated in subcellular space during cell migration. Immunofluorescence microscopy and biochemical enrichment of pseudopodia showed that type II regulatory subunits of PKA and PKA activity are enriched in protrusive cellular structures formed during chemotaxis. This enrichment correlates with increased phosphorylation of key cytoskeletal substrates for PKA, including the vasodilator-stimulated phosphoprotein (VASP) and the protein tyrosine phosphatase containing a PEST motif. Importantly, inhibition of PKA activity or its ability to interact with A kinase anchoring proteins inhibited the activity of the Rac GTPase within pseudopodia. This effect correlated with both decreased guanine nucleotide exchange factor activity and increased GTPase activating protein activity. Finally, inhibition of PKA anchoring, like inhibition of total PKA activity, inhibited pseudopod formation and chemotactic cell migration. These data demonstrate that spatial regulation of PKA via anchoring is an important facet of normal chemotactic cell movement.

  15. Expression and divalent cation binding properties of the novel chemotactic inflammatory protein psoriasin

    DEFF Research Database (Denmark)

    Vorum, H; Madsen, Peder; Rasmussen, H H;

    1996-01-01

    Psoriasin is a novel chemotactic inflammatory protein that possesses weak similarity to the S100 family members of Ca(2+)-binding proteins, and that is highly up-regulated in hyperproliferative psoriatic keratinocytes. Here we have used the psoriasin cDNA to express recombinant human (rh) psoriasin...... in Escherichia coli as a fusion protein containing a hexa His tag and a factor Xa cleavage site in the NH2-terminus. The protein was purified by affinity chromatography on Ni(2+)-nitrilotriacetic acid agarose, digested with factor Xa, further purified by ion-exchange chromatography and characterized by two...... in KCl and four in NaCl, with an affinity just below 1 x 10(4) M-1 for the first molecule. Thus psoriasin does not bind significant amounts of Zn2+ at physiological concentrations. Mg2+ and Ca2+ are bound anti-cooperatively and binding of each of the ions (Ca2+, Zn2+, or Mg2+), is accompanied...

  16. Jeans type instability for a chemotactic model of cellular aggregation

    CERN Document Server

    Chavanis, Pierre-Henri

    2008-01-01

    We consider an inertial model of chemotactic aggregation generalizing the Keller-Segel model and we study the linear dynamical stability of an infinite and homogeneous distribution of cells (bacteria, amoebae, endothelial cells,...) when inertial effects are accounted for. These inertial terms model cells directional persistance. We determine the condition of instability and the growth rate of the perturbation as a function of the cell density and the wavelength of the perturbation. We discuss the differences between overdamped (Keller-Segel) and inertial models. Finally, we show the analogy between the instability criterion for biological populations and the Jeans instability criterion in astrophysics.

  17. Diversity of chemotactic heterotrophic bacteria associated with arctic cyanobacteria.

    Science.gov (United States)

    Prasad, Sathish; Pratibha, Mambatta Shankaranarayanan; Manasa, Poorna; Buddhi, Sailaja; Begum, Zareena; Shivaji, Sisinthy

    2013-01-01

    The abundance and diversity of chemotactic heterotrophic bacteria associated with Arctic cyanobacteria was determined. The viable numbers ranged between 10(4) and 10(6) cell g(-1) cyanobacterial biomass. A total of 112 morphotypes, representing 22 phylotypes based on their 16S rRNA sequence similarity were isolated from the samples. All the phylotypes were Gram-negative with affiliation to the proteobacterial and bacteroidetes divisions. Among the 22 phylotypes, 14 were chemotactic to glucose. Majority of the phylotypes were psychrotolerant showing growth up to 30 °C. Representatives of Alphaproteobacteria, the genus Flavobacterium and the gammaproteobacterial Alcanivorax sp, were psychrophilic with growth at or below 18 °C. A significant percentage of phylotypes were pigmented (~68 %), rich in unsaturated membrane fatty acids and tolerated pH values and NaCl concentrations between 5.0-8.0 and 0.15-1.0 M, respectively. The percentages of phylotypes producing extracellular cold-active enzymes at 4 °C were amylase (18.18 %), lipase and urease (45.45 %), caseinase (59.09 %) and gelatinase (31.8 %). PMID:23053490

  18. Controlling neural activity in Caenorhabditis elegans to evoke chemotactic behavior

    Science.gov (United States)

    Kocabas, Askin; Shen, Ching-Han; Guo, Zengcai V.; Ramanathan, Sharad

    2013-03-01

    Animals locate and track chemoattractive gradients in the environment to find food. With its simple nervous system, Caenorhabditis elegans is a good model system in which to understand how the dynamics of neural activity control this search behavior. To understand how the activity in its interneurons coordinate different motor programs to lead the animal to food, here we used optogenetics and new optical tools to manipulate neural activity directly in freely moving animals to evoke chemotactic behavior. By deducing the classes of activity patterns triggered during chemotaxis and exciting individual neurons with these patterns, we identified interneurons that control the essential locomotory programs for this behavior. Notably, we discovered that controlling the dynamics of activity in just one interneuron pair was sufficient to force the animal to locate, turn towards and track virtual light gradients.

  19. Phenomenological understanding of aggregation and dispersion of chemotactic cells

    CERN Document Server

    Iwasa, Masatomo

    2011-01-01

    We present a simple model that describes the motion of a single chemotactic cell exposed to a traveling wave of the chemoattractant. The model incorporates two types of responses to stimulation by the chemoattractant, i.e., change in polarity and change in motility of the cell. The periodic change in motility is assumed to be induced by the periodic stimulation by the chemoattractant on the basis of previous observations. Consequently, net migration of the cell occurs in a particular direction with respect to wave propagation, which explains the migration of Dictyostelium cells in aggregation processes. The difference between two time delays from the stimulation to the two responses and the wave frequency determined by the frequency of the secretion of the chemoattractant are important parameters that determine the direction of migration and the effective interaction between cells in a population. This result explains the dispersed state of a population of vegetative cells and cells in preaggregation without ...

  20. Thrombin cleavage of osteopontin disrupts a pro-chemotactic sequence for dendritic cells, which is compensated by the release of its pro-chemotactic C-terminal fragment.

    Science.gov (United States)

    Shao, Zhifei; Morser, John; Leung, Lawrence L K

    2014-09-26

    Thrombin cleavage alters the function of osteopontin (OPN) by exposing an integrin binding site and releasing a chemotactic C-terminal fragment. Here, we examined thrombin cleavage of OPN in the context of dendritic cell (DC) migration to define its functional domains. Full-length OPN (OPN-FL), thrombin-cleaved N-terminal fragment (OPN-R), thrombin- and carboxypeptidase B2-double-cleaved N-terminal fragment (OPN-L), and C-terminal fragment (OPN-CTF) did not have intrinsic chemotactic activity, but all potentiated CCL21-induced DC migration. OPN-FL possessed the highest potency, whereas OPNRAA-FL had substantially less activity, indicating the importance of RGD. We identified a conserved (168)RSKSKKFRR(176) sequence on OPN-FL that spans the thrombin cleavage site, and it demonstrated potent pro-chemotactic effects on CCL21-induced DC migration. OPN-FLR168A had reduced activity, and the double mutant OPNRAA-FLR168A had even lower activity, indicating that these functional domains accounted for most of the pro-chemotactic activity of OPN-FL. OPN-CTF also possessed substantial pro-chemotactic activity, which was fully expressed upon thrombin cleavage and its release from the intact protein, because OPN-CTF was substantially more active than OPNRAA-FLR168A containing the OPN-CTF sequence within the intact protein. OPN-R and OPN-L possessed similar potency, indicating that the newly exposed C-terminal SVVYGLR sequence in OPN-R was not involved in the pro-chemotactic effect. OPN-FL and OPN-CTF did not directly bind to the CD44 standard form or CD44v6. In conclusion, thrombin cleavage of OPN disrupts a pro-chemotactic sequence in intact OPN, and its loss of pro-chemotactic activity is compensated by the release of OPN-CTF, which assumes a new conformation and possesses substantial activity in enhancing chemokine-induced migration of DCs. PMID:25112870

  1. Chemotactic Activity on Human Neutrophils to Streptococcus mutans

    Directory of Open Access Journals (Sweden)

    Tetiana Haniastuti

    2013-07-01

    Full Text Available Objective: The aim of this study was to evaluate chemotactic activity o neutrophil to S. mutans. Chemotaxis assay was performed in blind well chambers. Materials and Methods: Hanks balanced salt solution (HBSS containing 106 S. mutans,  108 S. mutans, 10-8 M fMLP, or HBSS alone were placed in the lower wells of the chamber and covered with polycorbonate membrane filter. Neutrophils suspension (2x105 cells was then placed in the upper compartment. After incubation for 60 mins at 37ºC in a humidified atmosphere with 5% CO2, the filters were removed and stained with Giemsa. Result: ANOVA revealed statistically significant differences among groups (p<0.05, indicating that S. mutans induced neutrophils chemotaxis. The number of neutrophils migration in response to 108 S. mutans and 106 S. mutans were signifiantly greater compared to fMLP (p<0.05. Conclusion: S. mutans may activate human neutrophils, resulting in the chemotaxis of the neutrophils.DOI: 10.14693/jdi.v16i2.99

  2. Human sperm pattern of movement during chemotactic re-orientation towards a progesterone source

    Institute of Scientific and Technical Information of China (English)

    Cecilia Soledad Blengini; Maria Eugenia Teves; Diego Rafael Unates; Hector Alejandro Guidobaldi; Laura Virginia Gatica; Laura Cecilia Giojalas

    2011-01-01

    @@ Human spermatozoa may chemotactically find out the egg by following an increasing gradient of attractant molecules.Although human spermatozoa have been observed to show several of the physiological characteristics of chemotaxis,the chemotactic pattern of movement has not been easy to describe.However,it is apparent that chemotactic cells may be identified while returning to the attractant source.This study characterizes the pattern of movement of human spermatozoa during chemotactic re-orientation towards a progesterone source,which is a physiological attractant candidate.By means of videomicroscopy and image analysis,a chemotactic pattern of movement was identified as the spermatozoon returned towards the source of a chemotactic concentration of progesterone (10 pmol l-1).First,as a continuation of its original path,the spermatozoon swims away from the progesterone source with linear movement and then turns back with a transitional movement that can be characterized by an increased velocity and decreased linearity.This sperm behaviour may help the spermatozoon to re-orient itself towards a progesterone source and may be used to identify the few cells that are undergoing chemotaxis at a given time.

  3. Enhanced Retention of Chemotactic Bacteria in a Pore Network with Residual NAPL Contamination.

    Science.gov (United States)

    Wang, Xiaopu; Lanning, Larry M; Ford, Roseanne M

    2016-01-01

    Nonaqueous-phase liquid (NAPL) contaminants are difficult to eliminate from natural aquifers due, in part, to the heterogeneous structure of the soil. Chemotaxis enhances the mixing of bacteria with contaminant sources in low-permeability regions, which may not be readily accessible by advection and dispersion alone. A microfluidic device was designed to mimic heterogeneous features of a contaminated groundwater aquifer. NAPL droplets (toluene) were trapped within a fine pore network, and bacteria were injected through a highly conductive adjacent macrochannel. Chemotactic bacteria (Pseudomonas putida F1) exhibited greater accumulation near the pore network at 0.5 m/day than both the nonchemotactic control and the chemotactic bacteria at a higher groundwater velocity of 5 m/day. Chemotactic bacteria accumulated in the vicinity of NAPL droplets, and the accumulation was 15% greater than a nonchemotactic mutant. Indirect evidence showed that chemotactic bacteria were retained within the contaminated low-permeability region longer than nonchemotactic bacteria at 0.25 m/day. This retention was diminished at 5 m/day. Numerical solutions of the bacterial-transport equations were consistent with the experimental results. Because toluene is degraded by P. putida F1, the accumulation of chemotactic bacteria around NAPL sources is expected to increase contaminant consumption and improve the efficiency of bioremediation.

  4. Collective Chemotactic Dynamics in the Presence of Self-Generated Fluid Flows

    CERN Document Server

    Lushi, Enkeleida; Shelley, Michael J

    2012-01-01

    In micro-swimmer suspensions locomotion necessarily generates fluid motion, and it is known that such flows can lead to collective behavior from unbiased swimming. We examine the complementary problem of how chemotaxis is affected by self-generated flows. A kinetic theory coupling run-and-tumble chemotaxis to the flows of collective swimming shows separate branches of chemotactic and hydrodynamic instabilities for isotropic suspensions, the first driving aggregation, the second producing increased orientational order in suspensions of "pushers" and maximal disorder in suspensions of "pullers". Nonlinear simulations show that hydrodynamic interactions can limit and modify chemotactically-driven aggregation dynamics. In puller suspensions the dynamics form aggregates that are mutually-repelling due to the non-trivial flows. In pusher suspensions chemotactic aggregation can lead to destabilizing flows that fragment the regions of aggregation.

  5. Crosstalk between medulloblastoma cells and endothelium triggers a strong chemotactic signal recruiting T lymphocytes to the tumor microenvironment.

    Directory of Open Access Journals (Sweden)

    Vita S Salsman

    Full Text Available Cancer cells can live and grow if they succeed in creating a favorable niche that often includes elements from the immune system. While T lymphocytes play an important role in the host response to tumor growth, the mechanism of their trafficking to the tumor remains poorly understood. We show here that T lymphocytes consistently infiltrate the primary brain cancer, medulloblastoma. We demonstrate, both in vitro and in vivo, that these T lymphocytes are attracted to tumor deposits only after the tumor cells have interacted with tumor vascular endothelium. Macrophage Migration Inhibitory Factor (MIF" is the key chemokine molecule secreted by tumor cells which induces the tumor vascular endothelial cells to secrete the potent T lymphocyte attractant "Regulated upon Activation, Normal T-cell Expressed, and Secreted (RANTES." This in turn creates a chemotactic gradient for RANTES-receptor bearing T lymphocytes. Manipulation of this pathway could have important therapeutic implications.

  6. Chemotactic signal transduction and phosphate metabolism as adaptive strategies during citrus canker induction by Xanthomonas citri.

    Science.gov (United States)

    Moreira, Leandro Marcio; Facincani, Agda Paula; Ferreira, Cristiano Barbalho; Ferreira, Rafael Marine; Ferro, Maria Inês Tiraboshi; Gozzo, Fabio Cesar; de Oliveira, Julio Cezar Franco; Ferro, Jesus Aparecido; Soares, Márcia Regina

    2015-03-01

    The genome of Xanthomonas citri subsp. Citri strain 306 pathotype A (Xac) was completely sequenced more than 10 years; to date, few studies involving functional genomics Xac and its host compatible have been developed, specially related to adaptive events that allow the survival of Xac within the plant. Proteomic analysis of Xac showed that the processes of chemotactic signal transduction and phosphate metabolism are key adaptive strategies during the interaction of a pathogenic bacterium with its plant host. The results also indicate the importance of a group of proteins that may not be directly related to the classical virulence factors, but that are likely fundamental to the success of the initial stages of the infection, such as methyl-accepting chemotaxis protein (Mcp) and phosphate specific transport (Pst). Furthermore, the analysis of the mutant of the gene pstB which codifies to an ABC phosphate transporter subunit revealed a complete absence of citrus canker symptoms when inoculated in compatible hosts. We also conducted an in silico analysis which established the possible network of genes regulated by two-component systems PhoPQ and PhoBR (related to phosphate metabolism), and possible transcriptional factor binding site (TFBS) motifs of regulatory proteins PhoB and PhoP, detaching high degree of conservation of PhoB TFBS in 84 genes of Xac genome. This is the first time that chemotaxis signal transduction and phosphate metabolism were therefore indicated to be fundamental to the process of colonization of plant tissue during the induction of disease associated with Xanthomonas genus bacteria. PMID:25403594

  7. Chemotactic signal transduction and phosphate metabolism as adaptive strategies during citrus canker induction by Xanthomonas citri.

    Science.gov (United States)

    Moreira, Leandro Marcio; Facincani, Agda Paula; Ferreira, Cristiano Barbalho; Ferreira, Rafael Marine; Ferro, Maria Inês Tiraboshi; Gozzo, Fabio Cesar; de Oliveira, Julio Cezar Franco; Ferro, Jesus Aparecido; Soares, Márcia Regina

    2015-03-01

    The genome of Xanthomonas citri subsp. Citri strain 306 pathotype A (Xac) was completely sequenced more than 10 years; to date, few studies involving functional genomics Xac and its host compatible have been developed, specially related to adaptive events that allow the survival of Xac within the plant. Proteomic analysis of Xac showed that the processes of chemotactic signal transduction and phosphate metabolism are key adaptive strategies during the interaction of a pathogenic bacterium with its plant host. The results also indicate the importance of a group of proteins that may not be directly related to the classical virulence factors, but that are likely fundamental to the success of the initial stages of the infection, such as methyl-accepting chemotaxis protein (Mcp) and phosphate specific transport (Pst). Furthermore, the analysis of the mutant of the gene pstB which codifies to an ABC phosphate transporter subunit revealed a complete absence of citrus canker symptoms when inoculated in compatible hosts. We also conducted an in silico analysis which established the possible network of genes regulated by two-component systems PhoPQ and PhoBR (related to phosphate metabolism), and possible transcriptional factor binding site (TFBS) motifs of regulatory proteins PhoB and PhoP, detaching high degree of conservation of PhoB TFBS in 84 genes of Xac genome. This is the first time that chemotaxis signal transduction and phosphate metabolism were therefore indicated to be fundamental to the process of colonization of plant tissue during the induction of disease associated with Xanthomonas genus bacteria.

  8. Draft Genome Sequence of Halomonas sp. KHS3, a Polyaromatic Hydrocarbon-Chemotactic Strain

    OpenAIRE

    Gasperotti, Ana Florencia; Studdert, Claudia Alicia; Revale, Santiago; Herrera Seitz, María Karina

    2015-01-01

    The draft genome sequence of Halomonas sp. KHS3, isolated from seawater from Mar del Plata harbor, is reported. This strain is able to grow using aromatic compounds as a carbon source and shows strong chemotactic response toward these substrates. Genes involved in motility, chemotaxis, and degradation of aromatic hydrocarbons were identified.

  9. Monocyte chemotactic protein-1 expression in coronary atherosclerosis plaque of sudden coronary death patients

    Institute of Scientific and Technical Information of China (English)

    冯相平

    2006-01-01

    Objective To investigate the expression of monocyte chemotactic protein 1 (MCP-1) in coronary atherosclerosis plaque of sudden coronary death (SCD) patients and the relationship between MCP-1 expression and SCD. Methods Autopsy heart samples (n=90) collected during 2001 - 2003 were divided to SCD group (n=

  10. Chemotactic and mitogenic stimuli of neuronal apoptosis in patients with medically intractable temporal lobe epilepsy

    Science.gov (United States)

    Fiala, Milan; Avagyan, Hripsime; Merino, Jose Joaquin; Bernas, Michael; Valdivia, Juan; Espinosa-Jeffrey, Araceli; Witte, Marlys; Weinand, Martin

    2012-01-01

    To identify the upstream signals of neuronal apoptosis in patients with medically intractable temporal lobe epilepsy (TLE), we evaluated by immunohistochemistry and confocal microscopy brain tissues of 13 TLE patients and 5 control patients regarding expression of chemokines and cell-cycle proteins. The chemokine RANTES (CCR5) and other CC-chemokines and apoptotic markers (caspase-3, -8, -9) were expressed in lateral temporal cortical and hippocampal neurons of TLE patients, but not in neurons of control cases. The chemokine RANTES is usually found in cytoplasmic and extracellular locations. However, in TLE neurons, RANTES was displayed in an unusual location, the neuronal nuclei. In addition, the cell-cycle regulatory transcription factor E2F1 was found in an abnormal location in neuronal cytoplasm. The pro-inflammatory enzyme cyclooxygenase-2 and cytokine interleukin-1β were expressed both in neurons of patients suffering from temporal lobe epilepsy and from cerebral trauma. The vessels showed fibrin leakage, perivascular macrophages and expression of IL-6 on endothelial cells. In conclusion, the cytoplasmic effects of E2F1 and nuclear effects of RANTES might have novel roles in neuronal apoptosis of TLE neurons and indicate a need to develop new medical and/or surgical neuroprotective strategies against apoptotic signaling by these molecules. Both RANTES and E2F1 signaling are upstream from caspase activation, thus the antagonists of RANTES and/or E2F1 blockade might be neuroprotective for patients with medically intractable temporal lobe epilepsy. The results have implications for the development of new medical and surgical therapies based on inhibition of chemotactic and mitogenic stimuli of neuronal apoptosis in patients with medically intractable temporal lobe epilepsy. PMID:22444245

  11. TNF-alpha associated with extracellular matrix fibronectin provides a stop signal for chemotactically migrating T cells.

    Science.gov (United States)

    Franitza, S; Hershkoviz, R; Kam, N; Lichtenstein, N; Vaday, G G; Alon, R; Lider, O

    2000-09-01

    The migration of T cells into extravascular sites of inflammation is regulated by information derived from the molecular structure of the invaded tissue and from chemokine and cytokine gradients in the context of the extracellular matrix (ECM). Although recent studies have highlighted the role of particular chemoattractants in leukocyte migration, to date little is known about how specific combinations of contextual signals control the migration of leukocytes and their localization at sites of inflammation. Here we studied the interplay between a pleiotropic cytokine, TNF-alpha, and two prototypic chemoattractants, RANTES and stromal cell-derived factor-1alpha (SDF-1alpha), on human CD45RO+ T cells migrating within an ECM-like context. For this purpose, we used a newly constructed three-dimensional gel system designed to follow, in real time, the migration of individual leukocytes along chemotactic gradients in vitro. We found that TNF-alpha, which binds the ECM protein fibronectin and lacks adhesion- and migration-promoting effects of its own, can act as a proadhesive cytokine on T cells exposed to RANTES and SDF-1alpha. Furthermore, fibronectin-complexed TNF-alpha provided anchorage signals to the T cells as they moved directionally along chemoattractive gradients. This effect of TNF-alpha required an intact TNF-alpha receptor II subtype on the migrating T cells. The anchoring effect of TNF-alpha appears to be specific; IL-2, an integrin-activating proadhesive cytokine, does not transmit stoppage signals to T cell migration induced by RANTES. Thus, TNF-alpha present in the ECM at sites of inflammation may function to anchor T cells recruited to these sites by chemotactic signals. PMID:10946305

  12. Enhanced Retention of Chemotactic Bacteria in a Pore Network with Residual NAPL Contamination

    Science.gov (United States)

    Ford, R.; Wang, X.

    2013-12-01

    Nonaqueous phase liquid (NAPL) contaminants are difficult to eliminate from natural aquifers due, in part, to the heterogeneous structure of the soil matrix. Residual NAPL ganglia remain trapped in regions where the hydraulic conductivity is relatively low. Bioremediation processes depend on adequate mixing of microbial populations and the groundwater contaminants that they degrade. The ability of bacteria to sense a chemical gradient and swim preferentially toward locations of higher concentration, known as chemotaxis, can enhance the mixing of bacteria with contaminant sources that may not be readily accessible by advection and dispersion alone. The impact of chemotaxis on bacterial abundance within a low conductivity NAPL-contaminated region of a well-characterized porous matrix was investigated. A microfluidic device was designed to mimic heterogeneous features of a contaminated groundwater system. NAPL ganglia (toluene) were trapped within a fine pore network, and bacteria were injected into the system through a highly conductive adjacent channel. Chemotactic bacteria (P. putida F1) migrated preferentially towards and accumulated in the vicinity of NAPL contaminant sources. The accumulation of chemotactic bacteria was 15% greater in comparison to a nonchemotactic mutant (P. putida F1 CheA). Bacteria in the microfluidic device were subjected to different flow velocities from 0.25 to 5 m/d encompassing the range of typical groundwater flow rates. Chemotactic bacteria exhibited greater accumulation near the intersection between the macrochannel and the porous network at a flow velocity of 0.5 m/d than both the nonchemotactic mutant control and the chemotactic bacteria at a higher flow velocity of 5 m/d. Breakthrough curves observed at the outlet provided indirect evidence that chemotactic bacteria were retained within the contaminated low permeable region for a longer time than the nonchemotactic bacteria at a flow velocity of 0.25 m/d. This retention was

  13. RANTES and chemotactic activity in synovial fluids from patients with rheumatoid arthritis and osteoarthritis.

    Science.gov (United States)

    Stanczyk, Joanna; Kowalski, Marek L; Grzegorczyk, Janina; Szkudlinska, Barbara; Jarzebska, Marzanna; Marciniak, Marek; Synder, Marek

    2005-12-14

    A massive accumulation of inflammatory cells in synovial tissues is a major pathological feature of rheumatoid arthritis (RA). Neutrophiles dominate synovial fluid while rheumatoid synovium is infiltrated with mononuclear cells. Mechanisms regulating influx of particular subpopulations of leukocytes into articular cavity and synovium compartment are not completely defined. An increasing amount of data supports a crucial role of a C-C chemokine RANTES in the RA pathogenesis. Our objective is to evaluate chemotactic activity for neutrophils (NCA), lymphocytes (LCA), and monocytes (MoCA) in SFs obtained from patients with RA and osteoarthritis (OA). We also aimed to characterise the relation between chemotactic activity, RANTES, and percentage distribution of leukocytes in SF. SFs from 11 patients with RA and 6 with OA were included in the study. Modified microchamber Boyden method was employed to assess chemotactic activity. Cytological and biochemical analysis of SF was performed. RANTES was measured with ELISA. Rheumatoid SFs were rich in cells with predominance of neutrophiles while osteoarthritic fluids were lymphocytic. RA SFs were also characterised by increased lactoferrin level. Both NCA and LCA were higher in SF from patients with RA (62 +/- 12 and 24 +/- 6 cells/HPF, resp) as compared to patients with OA (23 +/- 6; P < .05 and 6 +/- 2 cells/HPF; P < 0.05). The chemoattractive effect of RA SF was more pronounced on neutrophiles than on lymphocytes. RA SF expressed high RANTES levels (145+/- 36 pg/mL), while OA SF was characterised by only trace amount of this chemokine (2 +/- 1 pg/mL). We found positive correlation of RANTES with chemotactic activity for mononuclear cells (LCA + MoCA; R = 0.61; P < .05). Surprisingly, RANTES correlated also positively with neutrophiles number (R = 0.77; P < 0.001). Rheumatoid SF possesses strong chemotactic potency for leukocytes. RANTES is overexpressed in RA SF and is a potential mediator influencing intensity and

  14. Chemotactic effect of urokinase-type plasminogen activator on mouse spermatozoa in vitro

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The aim of this study is to investigate the chemotactic effect of urokinase-type plasminogen activator (uPA)on mouse spermatozoa.Capillary assays were applied to study the chemotactic activity of ascending and descending gradients of uPA.Firstly,the chemotactic effect of an ascending gradient of uPA on mouse spermatozoa was observed by counting the number of spermatozoa that migrated into the capillary after incubation with uPA for 5,10,20,and 30 min,respectively,compared with that after incubation with F10.Twenty minutes was a suitable incubation time to obtain a plateau of sperm accumulation.Meanwhile,to confirm the specific effect of uPA on mouse sperm chemotaxis,uPA inhibitor (PAI-1)and anti-uPAR rabbit IgG were added to the test solution containing 20 U/mL uPA,respectively.To exclude the possibility that PAI-1 and anti-uPAR rabbit IgG may affect sperm accumulation nonspecifically,PAIl and anti-uPAR rabbit IgG were added to F10,respectively.It was found that the chemotactic effect of uPA was neutralized completely by PAI-1 and anti-uPAR rabbit IgG.PAI-1 and anti-uPAR rabbit IgG had no neutralizing effect on the sperm chemotactic effect.Lastly,the sperm chemotaxis response to a descending gradient of uPA was also observed.Taken together,the results suggest that uPA can induce sperm chemotaxis in vitro by binding to its receptor on the sperm membrane and may act as a chemoattractant in precontacting sperm-egg communication thereby increasing the chance encounter of spermatozoa and eggs.

  15. Auto-chemotactic micro-swimmer suspensions: modeling, analysis and simulations

    CERN Document Server

    Lushi, Enkeleida; Shelley, Michael J

    2013-01-01

    Microorganisms can preferentially orient and move along gradients of a chemo-attractant (i.e., chemotax) while colonies of many microorganisms can collectively undergo complex dynamics in response to chemo-attractants that they themselves produce. For colonies or groups of micro-swimmers we investigate how an "auto-chemotactic" response that should lead to swimmer aggregation is affected by the non-trivial fluid flows that are generated by collective swimming. For this, we consider chemotaxis models based upon a hydrodynamic theory of motile suspensions that are fully coupled to chemo-attractant production, transport, and diffusion. Linear analysis of isotropically ordered suspensions reveals both an aggregative instability due to chemotaxis that occurs independently of swimmer type, and a hydrodynamic instability when the swimmers are "pushers". Nonlinear simulations show nonetheless that hydrodynamic interactions can significantly modify the chemotactically-driven aggregation dynamics in suspensions of "pus...

  16. Fucose-binding Lotus tetragonolobus lectin binds to human polymorphonuclear leukocytes and induces a chemotactic response.

    Science.gov (United States)

    VanEpps, D E; Tung, K S

    1977-09-01

    Fucose-binding L. tetragonolobus lectin to the surface of human polymorphonuclear leukocytes (PMN) and induces a chemotactic response. Both surface binding and chemotaxis are inhibited by free fucose but not by fructose, mannose, or galactose. The lectin-binding sites on PMN are unrelated to the A, B, or O blood group antigen. Utilization of this lectin should be a useful tool in isolating PMN membrane components and in analyzing the mechanism of neutrophil chemotaxis. PMID:330752

  17. Study of the Chemotactic Response of Multicellular Spheroids in a Microfluidic Device

    OpenAIRE

    Jose M Ayuso; Basheer, Haneen A.; Rosa Monge; Pablo Sánchez-Álvarez; Manuel Doblaré; Shnyder, Steven D.; Victoria Vinader; Kamyar Afarinkia; Luis J Fernández; Ignacio Ochoa

    2015-01-01

    We report the first application of a microfluidic device to observe chemotactic migration in multicellular spheroids. A microfluidic device was designed comprising a central microchamber and two lateral channels through which reagents can be introduced. Multicellular spheroids were embedded in collagen and introduced to the microchamber. A gradient of fetal bovine serum (FBS) was established across the central chamber by addition of growth media containing serum into one of the lateral channe...

  18. A chemotactic model for interaction of antagonistic microflora colonies: front asymptotics and numerical simulations.

    OpenAIRE

    Málaga Iguiñiz, Carlos; Minzoni, Antonmaria Alessio; Plaza, Ramón Gabriel; Simeoni, Chiara

    2013-01-01

    International audience This paper studies a two-dimensional chemotactic model for two species in which one of them produces a chemo-repellent for the other. It is shown asymptotically and numerically how the chemical inhibits the invasion of a moving front for the second species and how stable steady states, which depend on the chemical concentration, can be reached. The results qualitatively explain experimental observations by Swain and Ray (Microbiol. Res. 164(2), 2009), where colonies ...

  19. Chemotactic model for interaction of antagonistic microflora colonies and numerical simulations

    CERN Document Server

    Malaga, Carlos; Plaza, Ramon G; Simeoni, Chiara

    2011-01-01

    This paper studies a two-dimensional chemotactic model for two species in which one of them produces a chemo-repellent for the other. Under these circumstances, the chemical inhibits the invasion of a moving front for the second species. It is shown asymptotically and numerically how stable steady states, which depend on the chemical concentration, can be reached. The results qualitatively explain experimental observations by Swain and Ray, where colonies of bacteria produce metabolite agents which prevent the invasion of fungi.

  20. Elevated monocyte chemotactic proteins 1, 2, and 3 in pulmonary alveolar proteinosis are associated with chemokine receptor suppression.

    Science.gov (United States)

    Bonfield, Tracey L; John, Nejimol; Malur, Anagha; Barna, Barbara P; Culver, Daniel A; Kavuru, Mani S; Thomassen, Mary Jane

    2005-01-01

    Pulmonary alveolar proteinosis (PAP) is a rare autoimmune lung disease characterized by abnormal surfactant accumulation within alveolar macrophages, and circulating auto-antibodies against granulocyte-macrophage colony stimulating factor (GM-CSF) resulting in functional GM-CSF deficiency. Monocyte/macrophage chemotactic protein-1 (MCP-1) is elevated in PAP, suggesting association with the pathophysiology. Because PAP has been associated with inflammatory pulmonary changes, we hypothesized that other MCP family chemokines would be present and that Chemokine Chemotaxis Receptor 2 (CCR2) would be elevated on PAP mononuclear cells. Here we show for the first time that MCP-2 and MCP-3, like MCP-1, are highly elevated in PAP. We also confirm that PAP alveolar macrophages and not epithelial cells produce MCP-1, and that MCP-1 from PAP lung has functional chemoattractant activity. Surprisingly, CCR2 expression is diminished in PAP lymphocytes and alveolar macrophages compared to controls. Further, MCP-1 from PAP lung suppresses CCR2 expression in vitro, suggesting that in PAP, MCP-1 participates in an autocrine regulatory network in vivo. PMID:15596412

  1. Monocyte chemotactic protein-1 deficiency reduces spontaneous metastasis of Lewis lung carcinoma in mice fed a high-fat diet

    Science.gov (United States)

    Yan, Lin; Sundaram, Sneha

    2016-01-01

    Adipose-produced pro-inflammatory cytokines contribute to obesity and cancer. This 2×2 experiment was designed to investigate effects of monocyte chemotactic protein-1 (MCP-1) deficiency on pulmonary metastasis of Lewis lung carcinoma (LLC) in MCP-1 deficient and wild-type mice fed a modified AIN93G diet containing 16% and 45% of energy from corn oil, respectively. The high-fat diet significantly increased the number and size (cross-sectional area and volume) of lung metastases compared to the AIN93G control diet. Deficiency in MCP-1 reduced lung metastases by 37% in high-fat diet-fed mice; it reduced metastatic cross-sectional area by 46% and volume by 69% compared to wild-type mice. Adipose and plasma concentrations of MCP-1 were significantly higher in high-fat diet-fed wild-type mice than in their AIN93G-fed counterparts; they were not detectable in MCP-1 deficient mice regardless of diet. Plasma concentrations of plasminogen activator inhibitor-1, tumor necrosis factor-α, vascular endothelial growth factor and tissue inhibitor of metalloproteinase-1 were significantly higher in MCP-1 deficient mice compared to wild-type mice. We conclude that adipose-produced MCP-1 contributes to high-fat diet-enhanced metastasis. While MCP-1 deficiency reduces metastasis, the elevation of pro-inflammatory cytokines and angiogenic factors in the absence of MCP-1 may support the metastatic development and growth of LLC in MCP-1 deficient mice. PMID:27028862

  2. Effects of Garlic Oil on the Migration of Neutrophil-Like Cell Studied by Using a Chemotactic Gradient Labchip

    Directory of Open Access Journals (Sweden)

    Po-Chen Shih

    2010-01-01

    Full Text Available We have designed and fabricated a novel chemotactic gradient Labchip for studying cell migration quantitatively. Owing to the great potential of garlic and its preparations in developing antiinflammatory drugs, the aim of the present study is to investigate the effect of garlic oil on the locomotion of a neutrophil-like cell by measuring the dynamic features of cell migration including migration direction, average migration speed, chemotactic index (CI, and motility index (MI with the newly designed Labchip. We found that garlic oil treatment lowered the values of CI and MI and reduced the average speed of cell migration from 13 to 8 μm/min. The results indicate that garlic oil is a potential inhibitor for neutrophil-like cell migration and chemotactic responsiveness. By comparing with the effects of nocodazole and cytochalasin B, we also suggest that the antiinflammatory activity exhibited by garlic oil was mainly through inhibiting the assembly-disassembly processes of the cytoskeleton.

  3. Modeling of chemotactic steering of bacteria-based microrobot using a population-scale approach.

    Science.gov (United States)

    Cho, Sunghoon; Choi, Young Jin; Zheng, Shaohui; Han, Jiwon; Ko, Seong Young; Park, Jong-Oh; Park, Sukho

    2015-09-01

    The bacteria-based microrobot (Bacteriobot) is one of the most effective vehicles for drug delivery systems. The bacteriobot consists of a microbead containing therapeutic drugs and bacteria as a sensor and an actuator that can target and guide the bacteriobot to its destination. Many researchers are developing bacteria-based microrobots and establishing the model. In spite of these efforts, a motility model for bacteriobots steered by chemotaxis remains elusive. Because bacterial movement is random and should be described using a stochastic model, bacterial response to the chemo-attractant is difficult to anticipate. In this research, we used a population-scale approach to overcome the main obstacle to the stochastic motion of single bacterium. Also known as Keller-Segel's equation in chemotaxis research, the population-scale approach is not new. It is a well-designed model derived from transport theory and adaptable to any chemotaxis experiment. In addition, we have considered the self-propelled Brownian motion of the bacteriobot in order to represent its stochastic properties. From this perspective, we have proposed a new numerical modelling method combining chemotaxis and Brownian motion to create a bacteriobot model steered by chemotaxis. To obtain modeling parameters, we executed motility analyses of microbeads and bacteriobots without chemotactic steering as well as chemotactic steering analysis of the bacteriobots. The resulting proposed model shows sound agreement with experimental data with a confidence level <0.01. PMID:26487902

  4. Computational modeling of chemotactic signaling and aggregation of microglia around implantation site during deep brain stimulation

    Science.gov (United States)

    Silchenko, A. N.; Tass, P. A.

    2013-10-01

    It is well established that prolonged electrical stimulation of brain tissue causes massive release of ATP in the extracellular space. The released ATP and the products of its hydrolysis, such as ADP and adenosine, become the main elements mediating chemotactic sensitivity and motility of microglial cells via subsequent activation of P2Y2,12 as well as A3A and A2A adenosine receptors. The size of the sheath around the electrode formed by the microglial cells is an important criterion for the optimization of the parameters of electrical current delivered to brain tissue. Here, we study a purinergic signaling pathway underlying the chemotactic motion of microglia towards the implanted electrode during deep brain stimulation. We present a computational model describing formation of a stable aggregate around the implantation site due to the joint chemo-attractive action of ATP and ADP together with a mixed influence of extracellular adenosine. The model was built in accordance with the classical Keller-Segel approach and includes an equation for the cells' density as well as equations describing the hydrolysis of extracellular ATP via successive reaction steps ATP →ADP →AMP →adenosine. The results of our modeling allowed us to reveal the dependence of the width of the encapsulating layer around the electrode on the amount of ATP released due to permanent electrical stimulation. The dependences of the aggregates' size on the parameter governing the nonlinearity of interaction between extracellular adenosine and adenosine receptors are also analyzed.

  5. Effect of Monocyte Chemotactic Protein-1 on the Intraperitoneal Adhesion Formation

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In order to study the role of monocyte chemotactic protein-1 (MCP-1) in the intra-peritoneal adhesion formation, 23 infertile patients undergoing laparoscopic operation were divided into two groups: experimental group including 12 patients with intra-peritoneal adhesion and control group including 11 patients without intra-peritoneal adhesion. Peritoneal fluid (PF) and peritoneum were collected from these patients during laparoscopic examination. The expression levels of MCP-l protein and MCP-1 mRNA were detected by using enzyme-linked immunosorbent assay (ELISA) and dot blot analysis method respectively. It was found that the levels of MCP-1 protein in PF of the patients with peritoneal adhesion were significantly higher than in the control group (0. 44±0.11 ng/ml vs 0. 19+0. 09 ng/ml respectively, P<0. 01 ). The level of MCP-1 mRNA in the peritoneum of the patients with peritoneal adhesion was significantly higher than in the control group (48.61±3.72 vs 19. 87±2.54 respectively, P<0. 01). It was suggested that MCP-1 might play a role in the adhesion formation, and chemotactic cytokines expressing in the peritoneal mesothelial cells might be take part in the process.

  6. Chemotactic behavior of deep subsurface bacteria toward carbohydrates, amino acids and a chlorinated alkene

    Energy Technology Data Exchange (ETDEWEB)

    Lopez de Victoria, G. (Puerto Rico Univ., Rio Piedras (Puerto Rico). Dept. of Biology)

    1989-02-01

    The chemotactic behavior of deep terrestrial subsurface bacteria toward amino acids, carbohydrates and trichloroethylene was assayed using a modification of the capillary method and bacterial enumeration by acridine orange direct counts. Eleven isolates of bacteria isolated from six different geological formations were investigated. A bimodal response rather than an absolute positive or negative response was observed in most assays. Most of the isolates were positively chemotactic to low concentrations of substrates and were repelled by high concentrations of the same substrate. However, this was not the case for trichloroethylene (TCE) which was mostly an attractant and elicited the highest responses in all the isolates when compared with amino acids and carbohydrates. The movement rates of these isolates in aseptic subsurface sediments in the absence and presence of TCE were also determined using a laboratory model. All of the isolates showed distinct response range, peak, and threshold concentrations when exposed to the same substrates suggesting that they are possibly different species as has been inferred from DNA homology studies. 101 refs., 4 figs., 57 tabs.

  7. CONSTRUCTION OF EUKARYOTIC EXPRESSION VECTOR FOR HUMAN CCL21 AND CHARACTERIZATION OF ITS CHEMOTACTIC ACTIVITY

    Institute of Scientific and Technical Information of China (English)

    HOU Li; LIU Qi; JIAO Yu-lian; ZHANG Jie; WANG Lai-cheng; MA Chun-yan; CUI Bin; ZHANG Xue; ZHAO Yue-ran

    2006-01-01

    Objective: To obtain recombinant human CCL21 with biological activity from eukaryotic expression system for further use in cancer gene therapy. Methods: A fragment of human CCL21 gene was obtained from pSK-hCCL21 plasmid digested by Xho I and BamH I, inserted into the responding sites of eukaryotic expression vector pVAX1, and then transfected into COS-7 cells by electroporation method. The expression of hCCL21 protein was detected by western blotting analysis. The in vitro chemotaxis assay was used to test the chemotactic function of the expression product to lymphocytes. Results: Human CCL21 protein was expressed by transfected COS-7 cells with recombinant plasmid containing hCCL21 gene, and was verified by western blotting. The in vitro chemotaxis assay demonstrated that human CCL21 protein had a potent chemotactic function to lymphocytes. Conclusion: Human CCL21 was successfully and transiently expressed in eukaryotic cells, which lays some foundation for the study of CCL21 gene therapy in murine tumor models.

  8. A model for cell type localization in the migrating slug of Dictyostelium discoideum based on differential chemotactic sensitivity to cAMP and differential sensitivity to suppression of chemotaxis by ammonia

    Indian Academy of Sciences (India)

    Ira N Feit; Jeffrey Pawlikowski; Caroline Zawilski

    2007-03-01

    The three basic cell types in the migrating slug of Dictyostelium discoideum show differential chemotactic response to cyclic AMP (cAMP) and differential sensitivity to suppression of the chemotaxis by ammonia. The values of these parameters indicate a progressive maturation of chemotactic properties during the transdifferentiation of slug cell types. We present a model that explains the localization of the three cell types within the slug based on these chemotactic differences and on the maturation of their chemotactic properties.

  9. Boc SPPS of two hydrophobic peptides using a ''solubilising tail'' strategy : Dodecaalanine and chemotactic protein 10(42-55)

    NARCIS (Netherlands)

    Englebretsen, DR; Alewood, PF

    1996-01-01

    The solid phase syntheses of the hydrophobic peptides dodecaalanine and chemotactic protein-10(42-55) were achieved using a ''solubilising tail'' strategy. Peptide constructs of the form H-hydrophobic peptide-glycolamide ester-(Gly-Arg)(4)-Gly-OH were synthesised by Boc SPPS. The peptide-constructs

  10. How many consumer levels can survive in a chemotactic food chain?

    Institute of Scientific and Technical Information of China (English)

    Jing LIU; Chunhua OU

    2009-01-01

    We investigate the effect and the impact of predator-prey interactions, diffusivity and chemotaxis on the ability of survival of multiple consumer levels in a predator-prey microbial food chain. We aim at answering the question of how many consumer levels can survive from a dynamical system point of view. To solve this standing issue on food-chain length, first we construct a chemotactic food chain model. A priori bounds of the steady state populations are obtained. Then under certain sufficient conditions combining the effect of conversion efficiency, diffusivity and chemotaxis parameters, we derive the co-survival of all consumer levels, thus obtaining the food chain length of our model. Numerical simulations not only confirm our theoretical results, but also demonstrate the impact of conversion efficiency, diffusivity and chemotaxis behavior on the survival and stability of various consumer levels.

  11. Study of the Chemotactic Response of Multicellular Spheroids in a Microfluidic Device.

    Directory of Open Access Journals (Sweden)

    Jose M Ayuso

    Full Text Available We report the first application of a microfluidic device to observe chemotactic migration in multicellular spheroids. A microfluidic device was designed comprising a central microchamber and two lateral channels through which reagents can be introduced. Multicellular spheroids were embedded in collagen and introduced to the microchamber. A gradient of fetal bovine serum (FBS was established across the central chamber by addition of growth media containing serum into one of the lateral channels. We observe that spheroids of oral squamous carcinoma cells OSC-19 invade collectively in the direction of the gradient of FBS. This invasion is more directional and aggressive than that observed for individual cells in the same experimental setup. In contrast to spheroids of OSC-19, U87-MG multicellular spheroids migrate as individual cells. A study of the exposure of spheroids to the chemoattractant shows that the rate of diffusion into the spheroid is slow and thus, the chemoattractant wave engulfs the spheroid before diffusing through it.

  12. Study of the Chemotactic Response of Multicellular Spheroids in a Microfluidic Device.

    Science.gov (United States)

    Ayuso, Jose M; Basheer, Haneen A; Monge, Rosa; Sánchez-Álvarez, Pablo; Doblaré, Manuel; Shnyder, Steven D; Vinader, Victoria; Afarinkia, Kamyar; Fernández, Luis J; Ochoa, Ignacio

    2015-01-01

    We report the first application of a microfluidic device to observe chemotactic migration in multicellular spheroids. A microfluidic device was designed comprising a central microchamber and two lateral channels through which reagents can be introduced. Multicellular spheroids were embedded in collagen and introduced to the microchamber. A gradient of fetal bovine serum (FBS) was established across the central chamber by addition of growth media containing serum into one of the lateral channels. We observe that spheroids of oral squamous carcinoma cells OSC-19 invade collectively in the direction of the gradient of FBS. This invasion is more directional and aggressive than that observed for individual cells in the same experimental setup. In contrast to spheroids of OSC-19, U87-MG multicellular spheroids migrate as individual cells. A study of the exposure of spheroids to the chemoattractant shows that the rate of diffusion into the spheroid is slow and thus, the chemoattractant wave engulfs the spheroid before diffusing through it. PMID:26444904

  13. Study of the Chemotactic Response of Multicellular Spheroids in a Microfluidic Device

    Science.gov (United States)

    Ayuso, Jose M.; Basheer, Haneen A.; Monge, Rosa; Sánchez-Álvarez, Pablo; Doblaré, Manuel; Shnyder, Steven D.; Vinader, Victoria; Afarinkia, Kamyar

    2015-01-01

    We report the first application of a microfluidic device to observe chemotactic migration in multicellular spheroids. A microfluidic device was designed comprising a central microchamber and two lateral channels through which reagents can be introduced. Multicellular spheroids were embedded in collagen and introduced to the microchamber. A gradient of fetal bovine serum (FBS) was established across the central chamber by addition of growth media containing serum into one of the lateral channels. We observe that spheroids of oral squamous carcinoma cells OSC–19 invade collectively in the direction of the gradient of FBS. This invasion is more directional and aggressive than that observed for individual cells in the same experimental setup. In contrast to spheroids of OSC–19, U87-MG multicellular spheroids migrate as individual cells. A study of the exposure of spheroids to the chemoattractant shows that the rate of diffusion into the spheroid is slow and thus, the chemoattractant wave engulfs the spheroid before diffusing through it. PMID:26444904

  14. Biodegradation of naphthalene and anthracene by chemo-tactically active rhizobacteria of populus deltoides

    Directory of Open Access Journals (Sweden)

    Sandeep Bisht

    2010-12-01

    Full Text Available Several naphthalene and anthracene degrading bacteria were isolated from rhizosphere of Populus deltoides, which were growing in non-contaminated soil. Among these, four isolates, i.e. Kurthia sp., Micrococcus varians, Deinococcus radiodurans and Bacillus circulans utilized chrysene, benzene, toluene and xylene, in addition to anthracene and naphthalene. Kurthia sp and B. circulans showed positive chemotactic response for naphthalene and anthracene. The mean growth rate constant (K of isolates were found to increase with successive increase in substrate concentration (0.5 to 1.0 mg/50ml. B. circulans SBA12 and Kurthia SBA4 degraded 87.5% and 86.6% of anthracene while, Kurthia sp. SBA4, B. circulans SBA12, and M. varians SBA8 degraded 85.3 %, 95.8 % and 86.8 % of naphthalene respectively after 6 days of incubation as determined by HPLC analysis.

  15. Direct and indirect radioiodination of protein: comparative study of chemotactic peptide labeling

    International Nuclear Information System (INIS)

    The development of simple methods for protein radioiodination have stimulated the use of radioiodinated peptides in vivo. There are two basic methods for labeling proteins with radioiodine: direct labeling, reaction of an electrophilic radioiodine with functional activated groups on protein, like the phenol ring in the tyrosine residue, and the conjugation of a previously radioiodinated molecule to the protein, referred as indirect method. The great problem related to the direct radioiodination of proteins is the in vivo dehalogenation. This problem can be minimized if a non-phenolic prosthetic group is used in the indirect radioiodination of the peptide. The ATE prosthetic group, N-succinimidyl 3-(tri-n-butylstannyl) benzoate, when radioiodinated by electrophilic iododestannilation produces N-succinimidyl 3-[123l/131l] iodine benzoate (SIB) that is subsequently conjugated to the protein by the acylation of the lysine group. There are many radiopharmaceuticals employed in scintigraphic images of infection and inflammation used with some limitations. These limitations stimulated the improvement of a new class of radiopharmaceuticals, the receptor-specific related labeled peptides, as the mediators of the inflammatory response, that presents high affinity by receptors expressed in the inflammation process, and fast clearance from blood and non-target tissues. One of these molecules is the synthetic chemotactic peptide fNleLFNIeYK that presents potent chemotaxis for leukocytes, with high affinity by the receptors presented in polymorphonuclear leukocytes and mononuclear phagocytes. The objective of this work included the synthesis of ATE prosthetic group and comparative radioiodination of the chemotactic peptide fNleLFNIeYK by direct and indirect methods, with radiochemical purity determination and evaluation of in vivo and in vitro stability of the compounds. This work presented an original contribution in the comparative biological distribution studies of the

  16. Modification of β-Defensin-2 by Dicarbonyls Methylglyoxal and Glyoxal Inhibits Antibacterial and Chemotactic Function In Vitro.

    Directory of Open Access Journals (Sweden)

    Janna G Kiselar

    Full Text Available Beta-defensins (hBDs provide antimicrobial and chemotactic defense against bacterial, viral and fungal infections. Human β-defensin-2 (hBD-2 acts against gram-negative bacteria and chemoattracts immature dendritic cells, thus regulating innate and adaptive immunity. Immunosuppression due to hyperglycemia underlies chronic infection in Type 2 diabetes. Hyperglycemia also elevates production of dicarbonyls methylgloxal (MGO and glyoxal (GO.The effect of dicarbonyl on defensin peptide structure was tested by exposing recombinant hBD-2 (rhBD-2 to MGO or GO with subsequent analysis by MALDI-TOF MS and LC/MS/MS. Antimicrobial function of untreated rhBD-2 vs. rhBD-2 exposed to dicarbonyl against strains of both gram-negative and gram-positive bacteria in culture was determined by radial diffusion assay. The effect of dicarbonyl on rhBD-2 chemotactic function was determined by chemotaxis assay in CEM-SS cells.MGO or GO in vitro irreversibly adducts to the rhBD-2 peptide, and significantly reduces antimicrobial and chemotactic functions. Adducts derive from two arginine residues, Arg22 and Arg23 near the C-terminus, and the N-terminal glycine (Gly1. We show by radial diffusion testing on gram-negative E. coli and P. aeruginosa, and gram-positive S. aureus, and a chemotaxis assay for CEM-SS cells, that antimicrobial activity and chemotactic function of rhBD-2 are significantly reduced by MGO.Dicarbonyl modification of cationic antimicrobial peptides represents a potential link between hyperglycemia and the clinical manifestation of increased susceptibility to infection, protracted wound healing, and chronic inflammation in undiagnosed and uncontrolled Type 2 diabetes.

  17. Monocyte chemotactic protein-1 expression as a prognosic biomarker in patients with solid tumor: a meta analysis

    OpenAIRE

    Wang, Hong; Zhang, Qiongwen; Kong, Hongyu; Zeng, Yunhui; Hao, Meiqin; Yu, Ting; Peng, Jing; Xu, Zhao; Chen, Jingquan; Shi, Huashan

    2014-01-01

    Purpose: A great deal of studies have been performed on the prognostic value of monocyte chemotactic protein-1 (MCP-1) in solid tumors in recent years. However, no consistent outcomes are reported. Therefore, the prognostic value of MCP-1 still remains controversial in patients with solid tumors. Here we aimed to evaluate the prognostic value of MCP-1 expression for patients with solid tumors. Methods: Comprehensive literature was selected from PUBMED and EMBASE and clinical studies which rep...

  18. Comamonas testosteroni uses a chemoreceptor for tricarboxylic acid cycle intermediates to trigger chemotactic responses towards aromatic compounds.

    Science.gov (United States)

    Ni, Bin; Huang, Zhou; Fan, Zheng; Jiang, Cheng-Ying; Liu, Shuang-Jiang

    2013-11-01

    Bacterial chemotaxis towards aromatic compounds has been frequently observed; however, knowledge of how bacteria sense aromatic compounds is limited. Comamonas testosteroni CNB-1 is able to grow on a range of aromatic compounds. This study investigated the chemotactic responses of CNB-1 to 10 aromatic compounds. We constructed a chemoreceptor-free, non-chemotactic mutant, CNB-1Δ20, by disruption of all 19 putative methyl-accepting chemotaxis proteins (MCPs) and the atypical chemoreceptor in strain CNB-1. Individual complementation revealed that a putative MCP (tagged MCP2201) was involved in triggering chemotaxis towards all 10 aromatic compounds. The recombinant sensory domain of MCP2201 did not bind to 3- or 4-hydroxybenzoate, protocatechuate, catechol, benzoate, vanillate and gentisate, but bound oxaloacetate, citrate, cis-aconitate, isocitrate, α-ketoglutarate, succinate, fumarate and malate. The mutant CNB-1ΔpmdF that lost the ability to metabolize 4-hydroxybenzoate and protocatechuate also lost its chemotactic response to these compounds, suggesting that taxis towards aromatic compounds is metabolism-dependent. Based on the ligand profile, we proposed that MCP2201 triggers taxis towards aromatic compounds by sensing TCA cycle intermediates. Our hypothesis was further supported by the finding that introduction of the previously characterized pseudomonad chemoreceptor (McpS) for TCA cycle intermediates into CNB-1Δ20 likewise triggered chemotaxis towards aromatic compounds.

  19. A Worldwide Competition to Compare the Speed and Chemotactic Accuracy of Neutrophil-Like Cells

    Science.gov (United States)

    Wong, Elisabeth; Hamza, Bashar; Bae, Albert; Martel, Joseph; Kataria, Rama; Keizer-Gunnink, Ineke; Kortholt, Arjan; Van Haastert, Peter J. M.; Charras, Guillaume; Janetopoulos, Christopher; Irimia, Daniel

    2016-01-01

    Chemotaxis is the ability to migrate towards the source of chemical gradients. It underlies the ability of neutrophils and other immune cells to hone in on their targets and defend against invading pathogens. Given the importance of neutrophil migration to health and disease, it is crucial to understand the basic mechanisms controlling chemotaxis so that strategies can be developed to modulate cell migration in clinical settings. Because of the complexity of human genetics, Dictyostelium and HL60 cells have long served as models system for studying chemotaxis. Since many of our current insights into chemotaxis have been gained from these two model systems, we decided to compare them side by side in a set of winner-take-all races, the Dicty World Races. These worldwide competitions challenge researchers to genetically engineer and pharmacologically enhance the model systems to compete in microfluidic racecourses. These races bring together technological innovations in genetic engineering and precision measurement of cell motility. Fourteen teams participated in the inaugural Dicty World Race 2014 and contributed cell lines, which they tuned for enhanced speed and chemotactic accuracy. The race enabled large-scale analyses of chemotaxis in complex environments and revealed an intriguing balance of speed and accuracy of the model cell lines. The successes of the first race validated the concept of using fun-spirited competition to gain insights into the complex mechanisms controlling chemotaxis, while the challenges of the first race will guide further technological development and planning of future events. PMID:27332963

  20. A Worldwide Competition to Compare the Speed and Chemotactic Accuracy of Neutrophil-Like Cells.

    Science.gov (United States)

    Skoge, Monica; Wong, Elisabeth; Hamza, Bashar; Bae, Albert; Martel, Joseph; Kataria, Rama; Keizer-Gunnink, Ineke; Kortholt, Arjan; Van Haastert, Peter J M; Charras, Guillaume; Janetopoulos, Christopher; Irimia, Daniel

    2016-01-01

    Chemotaxis is the ability to migrate towards the source of chemical gradients. It underlies the ability of neutrophils and other immune cells to hone in on their targets and defend against invading pathogens. Given the importance of neutrophil migration to health and disease, it is crucial to understand the basic mechanisms controlling chemotaxis so that strategies can be developed to modulate cell migration in clinical settings. Because of the complexity of human genetics, Dictyostelium and HL60 cells have long served as models system for studying chemotaxis. Since many of our current insights into chemotaxis have been gained from these two model systems, we decided to compare them side by side in a set of winner-take-all races, the Dicty World Races. These worldwide competitions challenge researchers to genetically engineer and pharmacologically enhance the model systems to compete in microfluidic racecourses. These races bring together technological innovations in genetic engineering and precision measurement of cell motility. Fourteen teams participated in the inaugural Dicty World Race 2014 and contributed cell lines, which they tuned for enhanced speed and chemotactic accuracy. The race enabled large-scale analyses of chemotaxis in complex environments and revealed an intriguing balance of speed and accuracy of the model cell lines. The successes of the first race validated the concept of using fun-spirited competition to gain insights into the complex mechanisms controlling chemotaxis, while the challenges of the first race will guide further technological development and planning of future events. PMID:27332963

  1. Hydrocarbon biodegradation and dynamic laser speckle for detecting chemotactic responses at low bacterial concentration

    Institute of Scientific and Technical Information of China (English)

    Melina Nisenbaum; Gonzalo Hernán Sendra; Gastón Alfredo Cerdá Gilbert; Marcelo Scagliola; Jorge Froilán González; Silvia Elena Murialdo

    2013-01-01

    We report on the biodegradation of pure hydrocarbons and chemotaxis towards these compounds by an isolated chlorophenol degrader,Pseudomonas strain H.The biochemical and phylogenetic analysis of the 16S rDNA sequence identified Pseudomonas strain H as having 99.56% similarity with P.aeruginosa PA01.This strain was able to degrade n-hexadecane,1-undecene,1-nonene,1-decene,1-dodecene and kerosene.It grew in the presence of 1-octene,while this hydrocarbons is toxic to other hydrocarbons degraders.Pseudomonas strain H was also chemotactic towards n-hexadecane,kerosene,1-undecene and 1-dodecene.These results show that this Pseudomonas strain H is an attractive candidate for hydrocarbon-containing wastewater bioremediation in controlled environments.Since the classical standard techniques for detecting chemotaxis are not efficient at low bacterial concentrations,we demonstrate the use of the dynamic speckle laser method,which is simple and inexpensive,to confirm bacterial chemotaxis at low cell concentrations (less than 105 colony-forming unit per millilitre (CFU/mL)) when hydrocarbons are the attractants.

  2. Enhancement of Chemotactic Cell Aggregation by Haptotactic Cell-To-Cell Interaction.

    Directory of Open Access Journals (Sweden)

    Tae-Goo Kwon

    Full Text Available The crawling of biological cell is a complex phenomenon involving various biochemical and mechanical processes. Some of these processes are intrinsic to individual cells, while others pertain to cell-to-cell interactions and to their responses to extrinsically imposed cues. Here, we report an interesting aggregation dynamics of mathematical model cells, when they perform chemotaxis in response to an externally imposed global chemical gradient while they influence each other through a haptotaxis-mediated social interaction, which confers intriguing trail patterns. In the absence of the cell-to-cell interaction, the equilibrium population density profile fits well to that of a simple Keller-Segal population dynamic model, in which a chemotactic current density [Formula: see text] competes with a normal diffusive current density [Formula: see text], where p and ρ refer to the concentration of chemoattractant and population density, respectively. We find that the cell-to-cell interaction confers a far more compact aggregation resulting in a much higher peak equilibrium cell density. The mathematical model system is applicable to many biological systems such as swarming microglia and neutrophils or accumulating ants towards a localized food source.

  3. Influence of corticosteroids on chemotactic response and collagen metabolism of human skin fibroblasts.

    Science.gov (United States)

    Hein, R; Mauch, C; Hatamochi, A; Krieg, T

    1988-07-15

    Following chronic administration of corticosteroids in vivo, a number of complications occur, which mainly involve the metabolism of connective tissue cells. Therefore, several attempts have been made to develop corticosteroids, which show less pronounced side effects. Fibroblasts were kept in monolayer cultures and were exposed to corticosteroids demonstrating similar anti-inflammatory activity (prednicarbate, desoximetasone). Chemotaxis of fibroblasts was studied over 4 hr, protein and collagen synthesis were estimated using proteinchemical methods and also by dot blot hybridization. Corticosteroids used in a high dosage (10 microM) affected all biosynthetic capacities of the investigated fibroblasts. Protein synthesis and production of collagen types I and III were reduced and a similar decrease of mRNA levels for collagen type I could be found indicating an influence on the pretranslational control. In the same concentrations desoximetasone was much more active than prednicarbate. Fibroblast migration was dosage dependently inhibited from 10(-9) M to 10(-5) M for desoximetasone, while incubation with prednicarbate did not cause a reduction of the chemotactic response at concentrations lower than 10(-7) M. These data suggest that modifications of corticosteroids might result in a dissociation of some of their biological activities and can specifically influence their effects on biosynthetic capacities of fibroblasts. PMID:3395353

  4. Marangoni-driven chemotaxis, chemotactic collapse, and the Keller-Segel equation

    Science.gov (United States)

    Shelley, Michael; Masoud, Hassan

    2013-11-01

    Almost by definition, chemotaxis involves the biased motion of motile particles along gradients of a chemical concentration field. Perhaps the most famous model for collective chemotaxis in mathematical biology is the Keller-Segel model, conceived to describe collective aggregation of slime mold colonies in response to an intrinsically produced, and diffusing, chemo-attractant. Heavily studied, particularly in 2D where the system is ``super-critical'', it has been proved that the KS model can develop finite-time singularities - so-called chemotactic collapse - of delta-function type. Here, we study the collective dynamics of immotile particles bound to a 2D interface above a 3D fluid. These particles are chemically active and produce a diffusing field that creates surface-tension gradients along the surface. The resultant Marangoni stresses create flows that carry the particles, possibly concentrating them. Remarkably, we show that this system involving 3D diffusion and fluid dynamics, exactly yields the 2D Keller-Segel model for the surface-flow of active particles. We discuss the consequences of collapse on the 3D fluid dynamics, and generalizations of the fluid-dynamical model.

  5. Wave Patterns in Cell Membrane and Actin Cortex Uncoupled from Chemotactic Signals.

    Science.gov (United States)

    Gerisch, Günther; Ecke, Mary

    2016-01-01

    When cells of Dictyostelium discoideum orientate in a gradient of chemoattractant, they are polarized into a protruding front pointing toward the source of attractant, and into a retracting tail. Under the control of chemotactic signal inputs, Ras is activated and PIP3 is synthesized at the front, while the PIP3-degrading phosphatase PTEN decorates the tail region. As a result of signal transduction, actin filaments assemble at the front into dendritic structures associated with the Arp2/3 complex, in contrast to the tail region where a loose actin meshwork is associated with myosin-II and cortexillin, an antiparallel actin-bundling protein. In axenically growing strains of D. discoideum, wave patterns built by the same components evolve in the absence of any external signal input. Since these autonomously generated patterns are constrained to the plane of the substrate-attached cell surface, they are optimally suited to the optical analysis of state transitions between front-like and tail-like states of the membrane and the actin cortex. Here, we describe imaging techniques using fluorescent proteins to probe for the state of the membrane, the reorganization of the actin network, and the dynamics of wave patterns.

  6. Anti-coreceptor therapy drives selective T cell egress by suppressing inflammation-dependent chemotactic cues

    Science.gov (United States)

    Martin, Aaron J.; Clark, Matthew; Gojanovich, Gregory; Manzoor, Fatima; Miller, Keith; Kline, Douglas E.; Morillon, Y. Maurice; Wang, Bo

    2016-01-01

    There continues to be a need for immunotherapies to treat type 1 diabetes in the clinic. We previously reported that nondepleting anti-CD4 and -CD8 Ab treatment effectively reverses diabetes in new-onset NOD mice. A key feature of the induction of remission is the egress of the majority of islet-resident T cells. How this occurs is undefined. Herein, the effects of coreceptor therapy on islet T cell retention were investigated. Bivalent Ab binding to CD4 and CD8 blocked TCR signaling and T cell cytokine production, while indirectly downregulating islet chemokine expression. These processes were required for T cell retention, as ectopic IFN-γ or CXCL10 inhibited Ab-mediated T cell purging. Importantly, treatment of humanized mice with nondepleting anti–human CD4 and CD8 Ab similarly reduced tissue-infiltrating human CD4+ and CD8+ T cells. These findings demonstrate that Ab binding of CD4 and CD8 interrupts a feed-forward circuit by suppressing T cell–produced cytokines needed for expression of chemotactic cues, leading to rapid T cell egress from the islets. Coreceptor therapy therefore offers a robust approach to suppress T cell–mediated pathology by purging T cells in an inflammation-dependent manner.

  7. Enterohepatic circulation of bacterial chemotactic peptide in rats with experimental colitis

    International Nuclear Information System (INIS)

    The association of hepatobiliary disorders with colonic inflammation is well recognized. Although the pathophysiology is obscure, increased permeation of toxic bacterial products across the inflamed gut to the portal circulation might be one mechanism. Potentially toxic metabolites include N-formylated chemotactic peptides that are produced by several species of intestinal bacteria and can be detected in colonic fluid in vivo. To investigate the metabolic fate of one of these low molecular weight proinflammatory peptides, N-formyl L-methionine L-leucine 125I-L-tyrosine was introduced into colon loops of healthy rats (n = 10) and rats with experimental colitis (n = 15) induced by rectal instillation of 15% (vol/vol) acetic acid. Gut, liver, and blood radioactivity were monitored by external gamma-counting and radioactivity in bile was measured by biliary catheter drainage into a well counter. Bile was processed by high-performance liquid chromatography to determine the amount of intact, bioactive peptide excreted over 3 h. After colonic instillation of 1 nmol of peptide, the mean (+/- SEM) biliary excretion of intact peptide was 6.4 +/- 2.0 pmol in normal rats and 49.0 +/- 20 pmol in rats with colitis (p less than 0.01). An enterohepatic circulation of synthetic N-formyl L-methionine L-leucine L-tyrosine has been demonstrated in the rat. Experimental colitis was associated with an eightfold increase in biliary excretion of this proinflammatory bacterial peptide. Proinflammatory bacterial peptides synthesized by colonic bacteria could be important in the pathophysiology of colon inflammation and its frequently associated hepatobiliary complications

  8. Coccidioides Endospores and Spherules Draw Strong Chemotactic, Adhesive, and Phagocytic Responses by Individual Human Neutrophils.

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    Cheng-Yuk Lee

    Full Text Available Coccidioides spp. are dimorphic pathogenic fungi whose parasitic forms cause coccidioidomycosis (Valley fever in mammalian hosts. We use an innovative interdisciplinary approach to analyze one-on-one encounters between human neutrophils and two forms of Coccidioides posadasii. To examine the mechanisms by which the innate immune system coordinates different stages of the host response to fungal pathogens, we dissect the immune-cell response into chemotaxis, adhesion, and phagocytosis. Our single-cell technique reveals a surprisingly strong response by initially quiescent neutrophils to close encounters with C. posadasii, both from a distance (by complement-mediated chemotaxis as well as upon contact (by serum-dependent adhesion and phagocytosis. This response closely resembles neutrophil interactions with Candida albicans and zymosan particles, and is significantly stronger than the neutrophil responses to Cryptococcus neoformans, Aspergillus fumigatus, and Rhizopus oryzae under identical conditions. The vigorous in vitro neutrophil response suggests that C. posadasii evades in vivo recognition by neutrophils through suppression of long-range mobilization and recruitment of the immune cells. This observation elucidates an important paradigm of the recognition of microbes, i.e., that intact immunotaxis comprises an intricate spatiotemporal hierarchy of distinct chemotactic processes. Moreover, in contrast to earlier reports, human neutrophils exhibit vigorous chemotaxis toward, and frustrated phagocytosis of, the large spherules of C. posadasii under physiological-like conditions. Finally, neutrophils from healthy donors and patients with chronic coccidioidomycosis display subtle differences in their responses to antibody-coated beads, even though the patient cells appear to interact normally with C. posadasii endospores.

  9. Sonic hedgehog is a chemotactic neural crest cell guide that is perturbed by ethanol exposure.

    Science.gov (United States)

    Tolosa, Ezequiel J; Fernández-Zapico, Martín E; Battiato, Natalia L; Rovasio, Roberto A

    2016-01-01

    Our aim was to understand the involvement of Sonic hedgehog (Shh) morphogen in the oriented distribution of neural crest cells (NCCs) toward the optic vesicle and to look for potential disorders of this guiding mechanism after ethanol exposure. In vitro directional analysis showed the chemotactic response of NCCs up Shh gradients and to notochord co-cultures (Shh source) or to their conditioned medium, a response inhibited by anti-Shh antibody, receptor inhibitor cyclopamine and anti-Smo morpholino (MO). Expression of the Ptch-Smo receptor complex on in vitro NCCs was also shown. In whole embryos, the expression of Shh mRNA and protein was seen in the ocular region, and of Ptch, Smo and Gli/Sufu system on cephalic NCCs. Anti-Smo MO or Ptch-mutated plasmid (Ptch1(Δloop2)) impaired cephalic NCC migration/distribution, with fewer cells invading the optic region and with higher cell density at the homolateral mesencephalic level. Beads embedded with cyclopamine (Smo-blocking) or Shh (ectopic signal) supported the role of Shh as an in vivo guide molecule for cephalic NCCs. Ethanol exposure perturbed in vitro and in vivo NCC migration. Early stage embryos treated with ethanol, in a model reproducing Fetal Alcohol Syndrome, showed later disruptions of craniofacial development associated with abnormal in situ expression of Shh morphogen. The results show the Shh/Ptch/Smo-dependent migration of NCCs toward the optic vesicle, with the support of specific inactivation with genetic and pharmacological tools. They also help to understand mechanisms of accurate distribution of embryonic cells and of their perturbation by a commonly consumed teratogen, and demonstrate, in addition to its other known developmental functions, a new biological activity of cellular guidance for Shh. PMID:26979762

  10. Modulation of signalling in neutrophils activated by a chemotactic peptide: calcium regulates diacyl glycerol metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Korchak, H.M.; Vosshall, L.B.; Lundquist, K.F.

    1987-05-01

    Neutrophils activated by ligands such as the chemotactic peptide f-Met-Leu-Phe (FMLP) generate superoxide anion (O/sub 2//sup -/) and release specific and azurophil granule contents. The signalling for this response is thought to involve both elevated cytosolic Ca and protein kinase C activity. Receptor-occupation triggers a phospholipase C to cleave phosphatidyl inositol 4,5 bisphosphate (PIP/sub 2/) yielding inositol 1,4,5 trisphosphate, (IP/sub 3/), a trigger for intracellular Ca release, and diacyl glycerol (DG), which together with Ca activates protein kinase C. The DG can be metabolized to phosphatidic acid (PA). FMLP triggered a rapid increase in cytosolic Ca (fura-2). Loading cells with MAPTAM, and intracellular Ca buffer, suppressed this Ca transient in FMLP activated cells and inhibited O/sub 2//sup -/ generation to 12.5% of control, beta-glucuronidase release to 40.3% of control and lysozyme release to 55.1% of control. FMLP triggered a prompt decrease in PIP/sub 2/ in cells pre-labelled with /sup 32/P or /sup 3/H-inositol and an increase in PA and release of /sup 3/H-IP/sub 3/. A rapid increase in /sup 14/C-DG levels was also observed in /sup 14/C-glycerol pre-loaded cells activated by FMLP. Suppression of the Ca transient by buffering with MAPTAM inhibited elevation of /sup 14/C-DG. Breakdown of PIP/sub 2/ was not inhibited and elevation of /sup 32/P-PA was enhanced in MAPTAM loaded cells. Conversely, 200nM ionomycin which elevated cytosolic Ca to an equivalent level to 10/sup -7/M FMLP, triggered a rise in /sup 14/C-DG but not in PA.

  11. Osteopontin, a chemotactic protein with cytokine-like properties, is up-regulated in muscle injury caused by Bothrops lanceolatus (fer-de-lance) snake venom.

    Science.gov (United States)

    Barbosa-Souza, Valéria; Contin, Daniel Kiss; Filho, Waldemar Bonventi; de Araújo, Albetiza Lôbo; Irazusta, Silvia Pierre; da Cruz-Höfling, Maria Alice

    2011-10-01

    Osteopontin (OPN) is a chemotactic, adhesive protein whose receptors include some integrins and matrix proteins known to have role in inflammatory and repair processes. We examined the time course of OPN expression at acute and chronic stages after intramuscular injection of Bothrops lanceolatus venom in rats. Additionally, we examined the expression of CD68 (a marker for phagocytic macrophages) and the myogenic factors, myoD and myogenin. There was a biphasic upregulation of OPN (6-48 h and 3-14 days post-venom), i.e., during acute inflammation and myogenic cell proliferation and differentiation phases. OPN was detected in CD68 + macrophages, fibroblasts, normal and damaged myofibers, myoblasts and myotubes. Myogenin was expressed in the cytoplasm (atypical pattern) and nucleus of myoblasts and myotubes from 18 h to 7 days, after which it was expressed only in nuclei. Macrophage numbers, OPN and myogenin expression were still elevated at 7, 14 and 7 days. At 3 days, when OPN achieved the peak, some clusters of myoblasts were within regions of intense collagen deposition. Fibrosis may represent limitation for repairing processes and may explain the small diameter of regenerated fibers at 21 days post-venom. The expression of OPN in the course of venom-induced damage and regeneration suggests stages-specific mediation role along the whole process. PMID:21839764

  12. Quantitative modeling of Escherichia coli chemotactic motion in environments varying in space and time.

    Directory of Open Access Journals (Sweden)

    Lili Jiang

    2010-04-01

    Full Text Available Escherichia coli chemotactic motion in spatiotemporally varying environments is studied by using a computational model based on a coarse-grained description of the intracellular signaling pathway dynamics. We find that the cell's chemotaxis drift velocity v(d is a constant in an exponential attractant concentration gradient [L] proportional, variantexp(Gx. v(d depends linearly on the exponential gradient G before it saturates when G is larger than a critical value G(C. We find that G(C is determined by the intracellular adaptation rate k(R with a simple scaling law: G(C infinity k(1/2(R. The linear dependence of v(d on G = d(ln[L]/dx directly demonstrates E. coli's ability in sensing the derivative of the logarithmic attractant concentration. The existence of the limiting gradient G(C and its scaling with k(R are explained by the underlying intracellular adaptation dynamics and the flagellar motor response characteristics. For individual cells, we find that the overall average run length in an exponential gradient is longer than that in a homogeneous environment, which is caused by the constant kinase activity shift (decrease. The forward runs (up the gradient are longer than the backward runs, as expected; and depending on the exact gradient, the (shorter backward runs can be comparable to runs in a spatially homogeneous environment, consistent with previous experiments. In (spatial ligand gradients that also vary in time, the chemotaxis motion is damped as the frequency omega of the time-varying spatial gradient becomes faster than a critical value omega(c, which is controlled by the cell's chemotaxis adaptation rate k(R. Finally, our model, with no adjustable parameters, agrees quantitatively with the classical capillary assay experiments where the attractant concentration changes both in space and time. Our model can thus be used to study E. coli chemotaxis behavior in arbitrary spatiotemporally varying environments. Further experiments are

  13. Chemotactic response of plant-growth-promoting bacteria towards roots of vesicular-arbuscular mycorrhizal tomato plants.

    Science.gov (United States)

    Gupta Sood, Sushma

    2003-08-01

    The chemotactic responses of the plant-growth-promoting rhizobacteria Azotobacter chroococcum and Pseudomonas fluorescens to roots of vesicular-arbuscular mycorrhizal (Glomus fasciculatum) tomato plants were determined. A significantly (P=0.05) greater number of bacterial cells of wild strains were attracted towards vesicular-arbuscular mycorrhizal tomato roots compared to non-vesicular-arbuscular mycorrhizal tomato roots. Substances exuded by roots served as chemoattractants for these bacteria. P. fluorescens was strongly attracted towards citric and malic acids, which were predominant constituents in root exudates of tomato plants. A. chroococcum showed a stronger response towards sugars than amino acids, but the response was weakest towards organic acids. The effects of temperature, pH, and soil water matric potential on bacterial chemotaxis towards roots were also investigated. In general, significantly (P=0.05) greater chemotactic responses of bacteria were observed at higher water matric potentials (0, -1, and -5 kPa), slightly acidic to neutral pH (6, 6.5 and 7), and at 20-30 degrees C (depending on the bacterium) than in other environmental conditions. It is suggested that chemotaxis of P. fluorescens and A. chroococcum towards roots and their exudates is one of the several steps in the interaction process between bacteria and vesicular-arbuscular mycorrhizal roots. PMID:19719591

  14. In vitro inhibitory effects of Moringa oleifera leaf extract and its major components on chemiluminescence and chemotactic activity of phagocytes.

    Science.gov (United States)

    Vongsak, Boonyadist; Gritsanapan, Wandee; Wongkrajang, Yuvadee; Jantan, Ibrahim

    2013-11-01

    The ethanol extract of Moringa oleifera Lam. leaves and its major constituents, crypto-chlorogenic acid, quercetin 3-O-glucoside and kaempferol 3-O-glucoside, were investigated on the respiratory burst of human whole blood and isolated human polymorphonuclear leukocytes (PMNs) using a luminol-based chemiluminescence assay. The chemotactic migration of PMNs was also investigated using the Boyden chamber technique. The ethanol extract demonstrated inhibitory activities on the oxidative burst and the chemotactic migration of PMNs. Quercetin 3-O-glucoside, crypto-chlorogenic acid, and kaempferol 3-O-glucoside, isolated from the extract, expressed relatively strong inhibitory activity on the oxidative burst of PMNs with IC50 values of 4.1, 6.7 and 7.0 microM, respectively, comparable with that of aspirin. They also demonstrated strong inhibition of chemotatic migration of PMNs with IC50 values of 9.5, 15.9 and 18.2 microM, respectively. The results suggest that M. oleifera leaves could modulate the immune response of human phagocytes, linking to its ethnopharmacological use as an anti-inflammatory agent. The immunomodulating activity of the plant was mainly due to its major components.

  15. MONOCYTE CHEMOTACTIC PROTEIN AND RESPONSE TO PEGYLATED INTERFERON-ALPHA-2A TREATMENT IN PATIENTS WITH CHRONIC HEPATITIS C (CHC) GENOTYPE 4.

    Science.gov (United States)

    Mohamed, Amal A; Sayed, Ola; Ali, Omnia E; Sayed, Ghadir A; Moustfa, Zainab; Elagawy, Waleed Ahmed

    2016-04-01

    The prevalence of hepatitis C virus (HCV) infection varies across the world, with the highest number of infections reported in Egypt. Monocyte chemotactic protein-1 (MCP-1) is a potent chemokine, and its hepatic expression is up-regulated during chronic HCV infection. Fifty naive patients with chronic hepatitis C in National Hepatology & Tropical Medicine Research Institute and 20 healthy volunteers as controls were enrolled in a prospective study designed with strict inclusion criteria to nullify the effect of confounding variables and further minimize selection bias. Fifty naive patients were treated with PEG-IFN-a2b, at a dose of 1801 g/kg subcutaneously every week plus ribavirin at a dose of 1000- 1200 mg/day, according to the patient's body weight, for 48 weeks. Quantification of HCV-RNA by real-time PCR and MCP-1 by ELISA were performed for every patient and controls. There was a sta- tistically significant difference between patients and control group as regards the quantity of MCP-1 (P < 0.05) (Mann-Whitney test) (P = 0.004). There was a significant difference between responders and nonresponses regarding MCP-1 (P < 0.05), responders showed a higher percentage of cases with initial MCP-1 < 306 (P < 0.05). We conclude the importance of the detection of MCP-1 expression at the start of therapy as a factor for assessing the likelihood of HCV genotype 4 patients to achieving a sustained virological response to treatment with IFN-a2 in combination with ribavirin. PMID:27363047

  16. Migration of Chemotactic Bacteria Transverse to Flow in Response to a Benzoate Source Plume Created in a Saturated Sand-Packed Microcosm

    Science.gov (United States)

    Ford, R.; Boser, B.

    2012-12-01

    Bioremediation processes depend on contact between microbial populations and the groundwater contaminants that they biodegrade. Chemotaxis, the ability of bacteria to sense a chemical gradient and swim preferentially toward locations of higher concentration, can enhance the transport of bacteria toward contaminant sources that may not be readily accessible by advection and dispersion alone. A two-dimensional rectangular-shaped microcosm packed with quartz sand was used to quantify the effect of chemotaxis on the migration of bacteria within a saturated model aquifer system. Artificial groundwater was pumped through the microcosm at a rate of approximately 1 m/day. A plume of sodium benzoate was created by continuous injection into an upper port of the microcosm to generate a chemical gradient in the vertical direction transverse to flow. Chemotactic bacteria, Pseudomonas putida F1, or the nonchemotactic mutant, P. putida F1 CheA, were injected with a conservative tracer in a port several centimeters below the benzoate position. As the injectates traversed the one-meter length of the microcosm, samples were collected from a dozen effluent ports to determine vertical concentration distributions for the bacteria, benzoate and tracer. A moment analysis was implemented to estimate the center of mass, variance, and skewness of the concentration profiles. The transverse dispersion coefficient and the transverse dispersivity for chemotactic and nonchemotactic bacteria were also evaluated. Experiments performed with a continuous injection of bacteria showed that the center of mass for chemotactic bacteria was closer to the benzoate source on average than the nonchemotactic control (relative to the conservative tracer). These results demonstrated that chemotaxis can increase bacterial transport toward contaminants, potentially enhancing the effectiveness of in situ bioremediation. Experiments with 2 cm and 3 cm spacing between bacteria and benzoate injection locations were

  17. Chemotactic Activity of Cyclophilin A in the Skin Mucus of Yellow Catfish (Pelteobagrus fulvidraco and Its Active Site for Chemotaxis

    Directory of Open Access Journals (Sweden)

    Farman Ullah Dawar

    2016-08-01

    Full Text Available Fish skin mucus is a dynamic barrier for invading pathogens with a variety of anti-microbial enzymes, including cyclophilin A (CypA, a multi-functional protein with peptidyl-prolyl cis/trans isomerase (PPIase activity. Beside various other immunological functions, CypA induces leucocytes migration in vitro in teleost. In the current study, we have discovered several novel immune-relevant proteins in yellow catfish skin mucus by mass spectrometry (MS. The CypA present among them was further detected by Western blot. Moreover, the CypA present in the skin mucus displayed strong chemotactic activity for yellow catfish leucocytes. Interestingly, asparagine (like arginine in mammals at position 69 was the critical site in yellow catfish CypA involved in leucocyte attraction. These novel efforts do not only highlight the enzymatic texture of skin mucus, but signify CypA to be targeted for anti-inflammatory therapeutics.

  18. Multiscale dynamics of biological cells with chemotactic interactions: from a discrete stochastic model to a continuous description

    CERN Document Server

    Alber, M; Glimm, T; Lushnikov, P M; Alber, Mark; Chen, Nan; Glimm, Tilmann; Lushnikov, Pavel M.

    2006-01-01

    The Cellular Potts Model (CPM) has been used for simulating various biological phenomena such as differential adhesion, fruiting body formation of the slime mold Dictyostelium discoideum, angiogenesis, cancer invasion, chondrogenesis in embryonic vertebrate limbs, and many others. In this paper, we derive continuous limit of discrete one dimensional CPM with the chemotactic interactions between cells in the form of a Fokker-Planck equation for the evolution of the cell probability density function. This equation is then reduced to the classical macroscopic Keller-Segel model. In particular, all coefficients of the Keller-Segel model are obtained from parameters of the CPM. Theoretical results are verified numerically by comparing Monte Carlo simulations for the CPM with numerics for the Keller-Segel model.

  19. The release of eosinophil chemotactic activity and eosinophil chemokinesis inhibitory activity by mononuclear cells from atopic asthmatic and non-atopic subjects

    Directory of Open Access Journals (Sweden)

    J. Grzegorczyk

    2000-01-01

    Full Text Available The goal of our study was to assess the chemotactic activity for eosinophils (ECA and neutrophils (NCA and histamine releasing activity (HRA in crude supernatants of mononuclear cells in monosensitized atopic asthmatics and healthy controls. Chemotactic activity for ECA and neutrophils was measured in supernatants of cultured mononuclear cells with modified Boyden’s chamber and HRA was assessed on healthy donor basophils. With respect to ECA generation two distinct subgroups of subjects were distinguished: releasers [ECA (+] and non-releasers [ECA (–]. In atopic and non-atopic ECA (+ the mean ECA index was 3.78 ± 0.49 and 2.47 ± 0.27 respectively (P > 0.05. Supernatants from the remaining subjects (seven of 22 atopic and five of 11 non-atopic did not express ECA, but revealed significant inhibitory activity for chemokinesis of eosinophils (mean chemotactic index 0.25 ± 0.16 and 0.48 ± 0.22 for atopic and non-atopic non-releasers respectively. Stimulation with antigen of MNC from atopic and with PHA from non-atopic ECA (– restored cells ability to release ECA. Sephadex gel chromatography revealed that supernatants of MNC contained chemotactic and chemokinesis inhibitory activity in different fractions. The spontaneous productions of NCA and HRA by mononuclear cells was sim ilar in ECA releasers and non-releasers, although the HRA was higher following stimulation with PHA in the non-atopic ECA (+ subgroup. Our study demonstrated, for the first time, that MNC are capable of generating not only chemotactic activity but also chemokinesis inhibitory activity for eosinophils.

  20. CCL7 Is a Protective Factor Secreted by Mechanically Loaded Osteocytes

    OpenAIRE

    Kitase, Y.; Lee, S.; Gluhak-Heinrich, J; Johnson, M.L.; Harris, S.E.; Bonewald, L. F.

    2014-01-01

    In a search for factors up-regulated by mechanical strain in osteocytes, we discovered that chemokine (C-C motif) ligand 7 (CCL7), a chemotactic myokine, was highly expressed in MLO-Y4 osteocyte-like cells. Although MLO-Y4 cells secrete potent chemotactic factors for osteoclast precursors, CCL7 was not responsible for this activity. CCL7 was increased in osteocytes in response to tooth movement in vivo. Since mechanical loading plays a crucial role in maintaining osteocyte viability, CCL7 was...

  1. Cloning, bacterial expression and biological characterization of recombinant human granulocyte chemotactic protein-2 and differential expression of granulocyte chemotactic protein-2 and epithelial cell-derived neutrophil activating peptide-78 mRNAs.

    Science.gov (United States)

    Froyen, G; Proost, P; Ronsse, I; Mitera, T; Haelens, A; Wuyts, A; Opdenakker, G; Van Damme, J; Billiau, A

    1997-02-01

    Human osteosarcoma cells secrete a novel C-X-C chemokine called granulocyte chemotactic protein-2 (GCP-2), which was previously identified by amino acid sequencing of the purified natural protein. In order to understand the role of this new protein in inflammatory reactions, we cloned GCP-2 DNA sequences to generate recombinant protein and specific DNA probes and primers. By means of PCR on cloned cDNA of osteosarcoma cells induced by interleukin-1 beta and fibroblasts induced by lipopolysaccharide plus dsRNA, the complete coding domain of GCP-2 was isolated. This sequence was cloned into the bacterial expression vector pHEN1 and, after induction, GCP-2 was secreted into the periplasm of Escherichia coli. Recombinant GCP-2 (rGCP-2) was purified and characterized by SDS/PAGE as a monomeric 6.5-kDa protein and by amino-terminal sequencing. The chemoattractive potency of GCP-2 for neutrophilic granulocytes was about 10-times less than that of interleukin-8 and the minimal effective dose was 10 ng/ml. However, at optimal dose (100 ng/ml) the maximal chemotactic response was comparable with that of interleukin-8. Both characteristics correspond with those of natural GCP-2. In addition, intracellular calcium release in neutrophils by recombinant GCP-2 was achieved with as little as 10 ng/ml. Quantitation studies using reverse transcriptase and the polymerase chain reaction revealed higher GCP-2 mRNA production in normal fibroblasts than in tumor cells. When compared with epithelial-cell-derived neutrophil-activating peptide-78 (ENA-78) mRNA, the GCP-2 mRNA levels were higher in all cell lines tested. In addition, GCP-2 and ENA-78 expression seem to be differentially regulated in that phorbol ester and lipopolysaccharide have opposing effects on their mRNA induction in diploid fibroblasts and epithelial cells, respectively. Interleukin-1 was demonstrated to be a general inducer for both chemokines, while interferon-gamma down-regulates their mRNA expression. The

  2. Effect of endogenous factors on the chemical perception of Grapholita molesta (Busck) (Lepidoptera: Tortricidae) to sex pheromone

    International Nuclear Information System (INIS)

    The oriental fruit moth, Grapholita molesta (Busck), stands out as one of the most important pest in Rosaceae orchards in Brazil. During feeding, caterpillars bore into shoots, branches and fruits, impairing the commercial production. This work aimed to study the effect of endogenous factors in the chemical perception and in the species chemotactic behavior, seeking to optimize monitoring and the behavioral control of this pest. We evaluated male electroantennographical (EAG) and chemotactical (olfactometry) responses to the synthetic sex pheromone in different ages, virgins or mated and fed or unfed. The EAG responses of males did not differ for all evaluated factors. Nevertheless, the chemotactical behavior of males seems to decrease with age, not varying as a function of mating or feeding conditions. The knowledge about the interference of these factors in G. molesta may help with the interpretation of fi eld results, allowing the development of suitable and reliable control measures based on infochemicals for behavioral control. (author)

  3. Using optical tweezers to examine the chemotactic force to a single inflammatory cell--eosinophil stimulated by chemoattractants prepared from Toxocara Canis larvae

    Science.gov (United States)

    Shih, Po-Chen; Su, Yi-Jr; Chen, Ke-Min; Jen, Lin-Ni; Liu, Cheng-tzu; Hsu, Long

    2005-08-01

    Granulocytes are a group of white blood cells belonging to the innate immune system in human and in murine in which eosinophils play an important role in worm infection-induced inflammation. The migration of these cells is well characterized and has been separated into four steps: rolling, adhesion, transendothelial migration, and chemotaxis, however, the physical characteristics of the chemotactic force to eosinophils from worm component remain largely unknown. Note that optical tweezers are featured in the manipulation of a single cell and the measurement of biological forces. Therefore, we propose to use optical tweezers to examine the chemotactic force to a eosinophil from a T. canis lavae preparation in terms of distance during the migration of eosinophil.

  4. Intelectin is required for IL-13-induced monocyte chemotactic protein-1 and -3 expression in lung epithelial cells and promotes allergic airway inflammation

    OpenAIRE

    Gu, Naibing; Kang, Guannan; Jin, Chang'E; Xu, Yongjian; ZHANG, ZHENXIANG; Erle, David J.; Zhen, Guohua

    2009-01-01

    Asthma is characterized by airway inflammation, mucus overproduction, airway hyperreactivity, and peribronchial fibrosis. Intelectin has been shown to be increased in airway epithelium of asthmatics. However, the role of intelectin in the pathogenesis of asthma is unknown. Airway epithelial cells can secrete chemokines such as monocyte chemotactic protein (MCP)-1 and -3 that play crucial roles in asthmatic airway inflammation. We hypothesized that intelectin plays a role in allergic airway in...

  5. Plasma Levels of Monocyte Chemotactic Protein-1 Are Associated with Clinical Features and Angiogenesis in Patients with Multiple Myeloma

    Directory of Open Access Journals (Sweden)

    Toni Valković

    2016-01-01

    Full Text Available The aim of this pilot study was to determine the plasma levels of monocyte chemotactic protein-1 (MCP-1 and possible associations with angiogenesis and the main clinical features of untreated patients with multiple myeloma (MM. ELISA was used to determine plasma MCP-1 levels in 45 newly diagnosed MM patients and 24 healthy controls. The blood vessels were highlighted by immunohistochemical staining, and computer-assisted image analysis was used for more objective and accurate determination of two parameters of angiogenesis: microvessel density (MVD and total vascular area (TVA. The plasma levels of MCP-1 were compared to these parameters and the presence of anemia, renal dysfunction, and bone lesions. A significant positive correlation was found between plasma MCP-1 concentrations and TVA (p=0.02. The MCP-1 levels were significantly higher in MM patients with evident bone lesions (p=0.01, renal dysfunction (p=0.02, or anemia (p=0.04. Therefore, our preliminary results found a positive association between plasma MCP-1 levels, angiogenesis (expressed as TVA, and clinical features in patients with MM. However, additional prospective studies with a respectable number of patients should be performed to authenticate these results and establish MCP-1 as a possible target of active treatment.

  6. Inhibition of chemiluminescence and chemotactic activity of phagocytes in vitro by the extracts of selected medicinal plants.

    Science.gov (United States)

    Jantan, Ibrahim; Harun, Nurul Hikmah; Septama, Abdi Wira; Murad, Shahnaz; Mesaik, M A

    2011-04-01

    The methanol extracts of 20 selected medicinal plants were investigated for their effects on the respiratory burst of human whole blood, isolated human polymorphonuclear leukocytes (PMNs) and isolated mice macrophages using a luminol/lucigenin-based chemiluminescence assay. We also tested the effect of the extracts on chemotactic migration of PMNs using the Boyden chamber technique. The extracts of Curcuma domestica L., Phyllanthus amarus Schum & Thonn and C. xanthorrhiza Roxb. were the samples producing the strongest oxidative burst of PMNs with luminol-based chemiluminescence, with IC(50) values ranging from 0.5 to 0.7 μg/ml. For macrophage cells, the extracts which showed strong suppressive activity for luminol-based chemiluminescence were C. xanthorrhiza and Garcinia mangostana L. Among the extracts studied, C. mangga Valton & Vazsjip, Piper nigrum L. and Labisia pumila var. alata showed strong inhibitory activity on lucigenin-amplified oxidative burst of PMNs, with IC(50) values ranging from 0.9 to 1.5 μg/ml. The extracts of Zingiber officinale Rosc., Alpinia galangal (L.) Willd and Averrhoa bilimbi Linn showed strong inhibition on the chemotaxic migration of cells, with IC(50) values comparable to that of ibuprofen (1.5 μg/ml). The results suggest that some of these plants were able to modulate the innate immune response of phagocytes at different steps, emphasizing their potential as a source of new immunomodulatory agents. PMID:21184195

  7. A new SPH scheme to model transport of chemotactic bacteria in porous media at the continuum scale

    Science.gov (United States)

    Avesani, Diego; Bellin, Alberto; Dumbser, Michael; Chiogna, Gabriele

    2015-04-01

    As recently shown chemotaxis, i.e. the movement of microorganisms toward or away from the concentration gradient of a chemical species, could have a fundamental role in the transport of bacteria through saturated porous media. Chemotactic bacteria could enhance bioremediation by directing their own motions to residual contaminants in less conductive zones of aquifers. The aim of the present work is to develop a proper numerical scheme to define and to quantify the magnitude and the role of chemotaxis in the complex groundwater system framework. We present a new class of meshless Lagrangian particle methods based on the Smooth Particle Hydrodinamics (SPH) formulation of Vila & Ben Moussa, combined with a new Weighted Essentially Non-Oscillatory (WENO) reconstruction technique on moving point clouds in multiple space dimensions. The purpose of this new scheme is to fully exploit the advantages of SPH among traditional meshbased and meshfree schemes and to overcome its problems for modeling chemotaxis in porous media. We test the new scheme against analytical reference solutions and we show, under the assumption of complete mixing at the Darcy scale, that chemotaxis may significantly affect the quantification of field-scale bacterial distribution, therefore influencing reactive mixing and degradation of contaminants.

  8. Aurantio-obtusin stimulates chemotactic migration and differentiation of MC3T3-E1 osteoblast cells.

    Science.gov (United States)

    Vishnuprasad, Chethala N; Tsuchiya, Tomoko; Kanegasaki, Shiro; Kim, Joon Ho; Han, Sung Soo

    2014-05-01

    Osteoporosis is one of the major metabolic bone diseases and is among the most challenging noncommunicable diseases to treat. Although there is an increasing interest in identifying bioactive molecules for the prevention and management of osteoporosis, such studies principally focus only on differentiation and mineralization of osteoblasts or inhibition of osteoclast activity. Stimulation of osteoblast migration must be a promising osteoanabolic strategy for improved metabolic bone disease therapy. In this study, we show that an anthraquinone derivative, aurantio-obtusin, stimulated chemotactic migration of MC3T3-E1 osteoblast cells in a concentration-dependent manner. The use of a real-time chemotaxis analyzing system, TAXIScan, facilitated the evaluation of both velocity and directionality of osteoblast migration in response to the compound. Besides migration, the compound stimulated osteoblast differentiation and mineralization. Taken together, the data presented in this paper demonstrate that aurantio-obtusin is a promising osteoanabolic compound of natural origin with potential therapeutic applications in the prevention of osteoporosis and other metabolic bone diseases.

  9. Erythropoietin has a mitogenic and positive chemotactic effect on endothelial cells.

    OpenAIRE

    Anagnostou, A; Lee, E. S.; Kessimian, N; Levinson, R.; Steiner, M.

    1990-01-01

    Erythropoietin is known to be a hematopoietic growth factor with a singularly specific action on the proliferation and differentiation of erythroid progenitor cells. We have observed a dose-dependent proliferative action of human recombinant erythropoietin on human umbilical vein endothelial cells and bovine adrenal capillary endothelial cells. Binding studies with radioiodinated recombinant human erythropoietin revealed a large number (approximately 27,000) of an apparent single class of rec...

  10. Erythropoietin has a mitogenic and positive chemotactic effect on endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Anagnostou, A.; Kessimian, N.; Steiner, M. (Memorial Hospital of Rhode Island, Pawtucket (USA) Brown Univ. Program in Medicine, Providence, RH (USA)); Lee, Eun Sun (Memorial Hospital of Rhode Island, Pawtucket (USA)); Levinson, R. (Brown Univ. Program in Medicine, Providence, RI (USA))

    1990-08-01

    Erythropoietin is known to be a hematopoietic growth factor with a singularly specific action on the proliferation and differentiation of erythroid progenitor cells. The authors have observed a dose-dependent proliferative action of human recombinant erythropoietin on human umbilical vein endothelial cells and bovine adrenal capillary endothelial cells. Binding studies with radioiodinated recombinant human erythropoietin revealed a large number ({approx}27,000) of an apparent single class of receptors with an affinity in the 10{sup {minus}9} M range. Linkage of the radiolabeled ligand to its receptor via a bifunctional crosslinking agent allowed them to identify an endothelial cell protein of 45 kDa as the principal receptor associated with this mitogenic effect of erythropoietin. Recombinant human erythropoietin also enhanced the migration of endothelial cells.

  11. Erythropoietin has a mitogenic and positive chemotactic effect on endothelial cells

    International Nuclear Information System (INIS)

    Erythropoietin is known to be a hematopoietic growth factor with a singularly specific action on the proliferation and differentiation of erythroid progenitor cells. The authors have observed a dose-dependent proliferative action of human recombinant erythropoietin on human umbilical vein endothelial cells and bovine adrenal capillary endothelial cells. Binding studies with radioiodinated recombinant human erythropoietin revealed a large number (∼27,000) of an apparent single class of receptors with an affinity in the 10-9 M range. Linkage of the radiolabeled ligand to its receptor via a bifunctional crosslinking agent allowed them to identify an endothelial cell protein of 45 kDa as the principal receptor associated with this mitogenic effect of erythropoietin. Recombinant human erythropoietin also enhanced the migration of endothelial cells

  12. Postoperative Changes in Aqueous Monocyte Chemotactic Protein-1 Levels and Bleb Morphology after Trabeculectomy vs. Ex-PRESS Shunt Surgery.

    Directory of Open Access Journals (Sweden)

    Kohei Shobayashi

    Full Text Available To evaluate the postoperative changes in blebs and levels of aqueous monocyte chemotactic protein-1 (MCP-1 after trabeculectomy vs. Ex-PRESS tube shunt surgery.Rabbits were subjected to trabeculectomy or Ex-PRESS tube shunt surgery and observed for up to 3 months. Intraocular pressure (IOP was measured using a rebound tonometer. The MCP-1 level was measured by enzyme-linked immunosorbent assay (ELISA. Bleb morphology was evaluated using photos and anterior-segment optical coherence tomography (OCT.There were no differences in bleb appearance or IOP at any time between the groups. Bleb wall density in the anterior-segment OCT image was significantly lower 1 week after surgery in the Ex-PRESS group than the trabeculectomy group. The MCP-1 level in control eyes was 304.1 ± 45.2 pg/mL. In the trabeculectomy group, the mean aqueous MCP-1 level was 1444.9, 1914.3, 1899.8, 516.4, 398.3, 427.3, 609.5, 1612.7, 386.2, and 167.9 pg/mL at 3, 6, and 12 h, and 1, 2, 5, 7, 14, 30, and 90 days after surgery, respectively. In the Ex-PRESS group, the corresponding values were 1744.0, 1372.0, 932.5, 711.7, 396.1, 487.3, 799.5, 1327.9, 293.6, and 184.0 pg/mL. There were no significant differences in the aqueous MCP-1 level between the groups at any time point.The postoperative changes were similar in the Ex-PRESS and trabeculectomy groups, except for bleb wall density in the anterior-segment OCT image. The postoperative aqueous MCP-1 level had bimodal peaks in both groups.

  13. The nuclear factor-κB–interleukin-6 signalling pathway mediating vascular inflammation

    OpenAIRE

    Allan R. Brasier

    2010-01-01

    Vascular inflammation is a common pathophysiological response to diverse cardiovascular disease processes, including atherosclerosis, myocardial infarction, congestive heart failure, and aortic aneurysms/dissection. Inflammation is an ordered process initiated by vascular injury that produces enhanced leucocyte adherence, chemotaxis, and finally activation in situ. This process is coordinated by local secretion of adhesion molecules, chemotactic factors, and cytokines whose expression is the ...

  14. Factoring

    OpenAIRE

    Lenstra, Arjen K.

    1994-01-01

    Factoring, finding a non-trivial factorization of a composite positive integer, is believed to be a hard problem. How hard we think it is, however, changes almost on a daily basis. Predicting how hard factoring will be in the future, an important issue for cryptographic applications of composite numbers, is therefore a challenging task. The author presents a brief survey of general purpose integer factoring algorithms and their implementations

  15. Rabbit neutrophil chemotactic protein (NCP) activates both CXCR1 and CXCR2 and is the functional homologue for human CXCL6.

    Science.gov (United States)

    Catusse, Julie; Struyf, Sofie; Wuyts, Anja; Weyler, Myke; Loos, Tamara; Gijsbers, Klara; Gouwy, Mieke; Proost, Paul; Van Damme, Jo

    2004-11-15

    Neutrophil chemotactic protein (NCP) is a rabbit CXC chemokine with activating and chemotactic properties on neutrophilic granulocytes. Although its selective activity on neutrophils is demonstrated, its interactions with specific chemokine receptors are not defined. For further functional characterization, NCP was chemically synthesized and was found to be equipotent as natural NCP in neutrophil chemotaxis. To identify its human homologue, we separately expressed two potential rabbit NCP receptors (CXCR1 and CXCR2) in Jurkat cells. Pure synthetic NCP was equally efficient to promote chemotaxis through either rabbit CXCR1 or CXCR2. Moreover, chemotaxis assays on rabbit CXCR1 and CXCR2 transfectants showed that NCP uses the same receptors as interleukin-8 (IL-8), a major rabbit CXC chemokine, but not rabbit GROalpha, which only recognized CXCR2. In addition, specific inhibitors for CXCR1 or CXCR2 reduced rabbit neutrophil chemotaxis induced by NCP and rabbit IL-8. Furthermore, NCP and the structurally related human CXCR1/CXCR2 agonist CXCL6/GCP-2 (granulocyte chemotactic protein-2) cross-desensitized each other in intracellular calcium release assays on human neutrophils, further indicating that both chemokines share the same receptors. The inflammatory role of NCP was also evidenced by its potent granulocytosis inducing capacity in rabbits upon systemic administration. This study provides in vitro and in vivo evidences that NCP is the functional rabbit homologue for human CXCL6/GCP-2 rather than the most related CXCR2 agonist CXCL5/ENA-78 (epithelial cell-derived neutrophil activating peptide-78). It is concluded that the rabbit is a better model to study human neutrophil activation compared to mice, which lack CXCL8/IL-8.

  16. Monocyte chemotactic protein 1 increases homing of mesenchymal stem cell to injured myocardium and neovascularization following myocardial infarction

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective:To investigate the effect of MCP-1 on mesenchymal stem cells(MSCs) homing to injured myocardium in a rat myocardial infarction(MI) model. Methods:Rat myocardial infarction model was established by permanent left anterior descending branch ligation. Mesenchymal stem cells from donor rats were cultured in IMDM and labeled with BrdU. The Rats were divided into two groups. Monocyte chemotactic protein 1(MCP-1) expression were measured by in situ hybridization and immunohistochemistry in the sham operated or infarcted hearts at 1,2, 4,7,14 and 28 days post operation in MCP-1 detection group. The rats were injected with MCP-1, anti-MCP-1 antibody or saline 4 days after myocardial infarction in intervention group. Then, a total of 5 × 106 cells in 2.5 ml of PBS were injected through the tail vein. The number of the labeled MSCs in the infarcted hearts was counted 3 days post injection. Cardiac function and blood vessel density were assessed 28 days post injection. Results:Self-generating MCP-1 expression was increased at the first day, peaked at the 7th day and decreased thereafter post MI and remained unchanged in sham operated hearts. The MSCs enrichment in the host hearts were more abundant in the MI groups than that in the non-Mi group(P = 0.000), the MSCs enrichment in the host hearts were more abundant in the MCP-1 injected group than that in the anti-MCP-1 antibody and saline injected groups (P = 0.000). Cardiac function was improved more in MCP-1 injected group than anti-MCP-1 antibody and saline injected groups(P= 0.000). Neovascularization in MCP-1 injected group significantly increased compared with that of other groups(P = 0.000). Conclusion: Myocardial MCP-1 expression was increased only in the early phase post MI. MCP-1 may enhance MSCs homing to the injured heart and improve cardiac function by promoting neovascularization.

  17. Critical chemotactic collapse

    Science.gov (United States)

    Lushnikov, Pavel M.

    2010-04-01

    A Keller-Segel model describes macroscopic dynamics of bacterial colonies and biological cells as well as dynamics of a gas of self-gravitating Brownian particles. Bacteria secret chemical which attracts other bacteria so that they move towards chemical gradient creating nonlocal attraction between bacteria. If bacterial (or Brownian particle) density exceeds a critical value then the density collapses (blows up) in a finite time which corresponds to bacterial aggregation or gravitational collapse. Collapse in the Keller-Segel model has striking qualitative similarities with a nonlinear Schrödinger equation including critical collapse in two dimensions and supercritical collapse in three dimensions. A self-similar solution near blow up point is studied in the critical two-dimensional case and it has a form of a rescaled steady state solution which contains a critical number of bacteria. Time dependence of scaling of that solution has square root scaling law with logarithmic modification.

  18. Critical chemotactic collapse

    OpenAIRE

    Lushnikov, Pavel M.

    2009-01-01

    A Keller-Segel model describes macroscopic dynamics of bacterial colonies and biological cells. Bacteria secret chemical which attracts other bacteria so that they move towards chemical gradient creating nonlocal attraction between bacteria. If bacterial density exceeds a critical value then the density collapses (blows up) in a finite time which corresponds to bacterial aggregation. Collapse in the Keller-Segel model has striking qualitative similarities with a nonlinear Schrodinger equation...

  19. Critical chemotactic collapse

    International Nuclear Information System (INIS)

    A Keller-Segel model describes macroscopic dynamics of bacterial colonies and biological cells as well as dynamics of a gas of self-gravitating Brownian particles. Bacteria secret chemical which attracts other bacteria so that they move towards chemical gradient creating nonlocal attraction between bacteria. If bacterial (or Brownian particle) density exceeds a critical value then the density collapses (blows up) in a finite time which corresponds to bacterial aggregation or gravitational collapse. Collapse in the Keller-Segel model has striking qualitative similarities with a nonlinear Schroedinger equation including critical collapse in two dimensions and supercritical collapse in three dimensions. A self-similar solution near blow up point is studied in the critical two-dimensional case and it has a form of a rescaled steady state solution which contains a critical number of bacteria. Time dependence of scaling of that solution has square root scaling law with logarithmic modification.

  20. Critical chemotactic collapse

    Energy Technology Data Exchange (ETDEWEB)

    Lushnikov, Pavel M., E-mail: plushnik@math.unm.ed [Department of Mathematics and Statistics, University of New Mexico, Albuquerque, NM 87131 (United States)

    2010-04-05

    A Keller-Segel model describes macroscopic dynamics of bacterial colonies and biological cells as well as dynamics of a gas of self-gravitating Brownian particles. Bacteria secret chemical which attracts other bacteria so that they move towards chemical gradient creating nonlocal attraction between bacteria. If bacterial (or Brownian particle) density exceeds a critical value then the density collapses (blows up) in a finite time which corresponds to bacterial aggregation or gravitational collapse. Collapse in the Keller-Segel model has striking qualitative similarities with a nonlinear Schroedinger equation including critical collapse in two dimensions and supercritical collapse in three dimensions. A self-similar solution near blow up point is studied in the critical two-dimensional case and it has a form of a rescaled steady state solution which contains a critical number of bacteria. Time dependence of scaling of that solution has square root scaling law with logarithmic modification.

  1. Effect of endogenous factors on the chemical perception of Grapholita molesta (Busck) (Lepidoptera: Tortricidae) to sex pheromone; Efeito de fatores endogenos na percepcao quimica de Grapholita molesta(Busck) (Lepidoptera: Tortricidae) ao feromonio sexual

    Energy Technology Data Exchange (ETDEWEB)

    Altafini, Deisi L.; Sant' Ana, Josue; Redaelli, Luiza R., E-mail: deisila@gmail.co [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Dept. de Fitossanidade. Programa de Pos-Graduacao em Fitotecnia

    2010-06-15

    The oriental fruit moth, Grapholita molesta (Busck), stands out as one of the most important pest in Rosaceae orchards in Brazil. During feeding, caterpillars bore into shoots, branches and fruits, impairing the commercial production. This work aimed to study the effect of endogenous factors in the chemical perception and in the species chemotactic behavior, seeking to optimize monitoring and the behavioral control of this pest. We evaluated male electroantennographical (EAG) and chemotactical (olfactometry) responses to the synthetic sex pheromone in different ages, virgins or mated and fed or unfed. The EAG responses of males did not differ for all evaluated factors. Nevertheless, the chemotactical behavior of males seems to decrease with age, not varying as a function of mating or feeding conditions. The knowledge about the interference of these factors in G. molesta may help with the interpretation of fi eld results, allowing the development of suitable and reliable control measures based on infochemicals for behavioral control. (author)

  2. Incorporation of stromal cell-derived factor-1 alpha in PCL/gelatin electrospun membranes for guided bone regeneration

    NARCIS (Netherlands)

    Ji, W.; Yang, F.; Ma, J.L.; Bouma, M.J.; Boerman, O.C.; Chen, Z.; Beucken, J.J.J.P van den; Jansen, J.B.M.J.

    2013-01-01

    The goal of this work was to evaluate the effect of membrane functionalization with a chemotactic factor on cell recruitment and bone formation in order to develop a bioactive membrane for guided bone regeneration (GBR) applications. To this end. GBR membranes were prepared by electrospinning using

  3. Tracking Chemotactic Migration of a Genetically Engineered Bacterium in the Presence of Constructed Nutrient Gradients Within a Sandy Aquifer in Cape Cod, Massachusetts

    Science.gov (United States)

    Harvey, R. W.; Ford, R. M.; Metge, D. W.; Wang, M.; Toepfer, A. A.; McGowan, S. B.

    2008-05-01

    Due to our increasing dependence upon groundwater resources, there is a growing need to remediate shallow aquifers contaminated with chlorinated solvents. Often, trichloroethene (TCE) travels into zones of low permeability thereby making removal difficult by traditional pump-and-treat technologies. In addition, degradation of TCE by native microbial communities can result in buildup of highly toxic intermediates such as vinyl chloride. Bioaugmentation, involving addition of specialized bacterial consortia to an aquifer, can facilitate more complete degradation into harmless byproducts. Also, it is believed that chemotaxis, the ability of bacteria to swim towards higher concentrations of a chemical perceived as beneficial to survival, may expedite movement of introduced bacteria to where they are needed. However, there is no quantitative information about chemotaxis at the field scale and the evidence for bacterial chemotaxis during bioaugmentation has been largely anecdotal. In this study, the chemotactic migration of the bacterium, Pseudomonas stutzeri in a TCE-contaminated, sand- and-gravel aquifer in Cape Cod, Massachusetts was measured. P. stutzeri is known to denitrify as well as degrade a variety of aromatic and chlorinated solvents and is often advocated as a candidate for bioaugmentation. This bacterium was genetically engineered to be resistant to ampicillin and produce blue- fluorescing protein (BFP) in order to facilitate maintaining the bacteria in pure culture and later to track them in the environment. The study involved a natural-gradient injection and recovery test in which vertical gradients of an electron donor (acetate) and acceptor (nitrate) were created within the sandy aquifer sediments above an amendment of the genetically engineered P. stutzeri. The bacteria, nitrate, and acetate were allowed to be advected with the natural flow of groundwater past close-interval, multi-level samplers that were installed downgradient from the points of

  4. 趋化因子在哮喘中的作用及研究进展%Research progress and effect of chemotactic factor in asthma

    Institute of Scientific and Technical Information of China (English)

    郭宇; 李燕; 陈庄

    2012-01-01

    哮喘是一种气道的慢性炎症性疾病,其主要病理特点是气道炎症反应,气道高反应性和气道重塑.在炎症过程中有多种细胞(如嗜酸性粒细胞,肥大细胞,T细胞,中性粒细胞,气道上皮细胞等)参与,其中嗜酸性粒细胞浸润是其主要特征,而对这些炎症细胞的活化和向气道迁移的过程中,趋化因子则发挥着重要作用.随着大量的趋化因子和其受体的发现以及对其与哮喘发生机制的研究,趋化因子和趋化因子受体有可能成为抗炎治疗的靶点.本文意在讨论趋化因子与这些炎症细胞的关系,以及是否可以通过调节哮喘发病过程中趋化因子及趋化因子受体来作用于TH1/TH2的平衡,以达到治疗哮喘的目的.%Asthma is a chronic inflammatory airway diseases, the main pathological feature is airway inflammation, airway hy-perresponsiveness and airway remodeling. These features ate orchestrated by inflammatory cells (such as eosinophils, mast cells, T cells, neutrophils, airway epithelial cells, etc.) in which eosinophil infiltration is the main feature, and in the process of these inflammatory cells activation and migration to the airway chemokines plays an important role. With the large number of studies on chemokines and their receptors in the discovery and mechanism of asthma, chemokines and chemokine receptors might become targets for anti -inflammatory therapy. This article aims to discuss the chemokine and the relationship between these inflammatory cells, and whether the pathogenesis of asthma by regulating chemokine and chemokine receptor to act on the TH1/TH2 balance in order to achieve the purpose of treatment of asthma.

  5. Cardiac Stem Cell Secretome Protects Cardiomyocytes from Hypoxic Injury Partly via Monocyte Chemotactic Protein-1-Dependent Mechanism.

    Science.gov (United States)

    Park, Chi-Yeon; Choi, Seung-Cheol; Kim, Jong-Ho; Choi, Ji-Hyun; Joo, Hyung Joon; Hong, Soon Jun; Lim, Do-Sun

    2016-01-01

    Cardiac stem cells (CSCs) were known to secrete diverse paracrine factors leading to functional improvement and beneficial left ventricular remodeling via activation of the endogenous pro-survival signaling pathway. However, little is known about the paracrine factors secreted by CSCs and their roles in cardiomyocyte survival during hypoxic condition mimicking the post-myocardial infarction environment. We established Sca-1+/CD31- human telomerase reverse transcriptase-immortalized CSCs (Sca-1+/CD31- CSCs(hTERT)), evaluated their stem cell properties, and paracrine potential in cardiomyocyte survival during hypoxia-induced injury. Sca-1+/CD31- CSCs(hTERT) sustained proliferation ability even after long-term culture exceeding 100 population doublings, and represented multi-differentiation potential into cardiomyogenic, endothelial, adipogenic, and osteogenic lineages. Dominant factors secreted from Sca-1+/CD31- CSCs(hTERT) were EGF, TGF-β1, IGF-1, IGF-2, MCP-1, HGF R, and IL-6. Among these, MCP-1 was the most predominant factor in Sca-1+/CD31- CSCs(hTERT) conditioned medium (CM). Sca-1+/CD31- CSCs(hTERT) CM increased survival and reduced apoptosis of HL-1 cardiomyocytes during hypoxic injury. MCP-1 silencing in Sca-1+/CD31- CSCs(hTERT) CM resulted in a significant reduction in cardiomyocyte apoptosis. We demonstrated that Sca-1+/CD31- CSCs(hTERT) exhibited long-term proliferation capacity and multi-differentiation potential. Sca-1+/CD31- CSCs(hTERT) CM protected cardiomyocytes from hypoxic injury partly via MCP-1-dependent mechanism. Thus, they are valuable sources for in vitro and in vivo studies in the cardiovascular field. PMID:27231894

  6. Monocyte chemotactic protein-1 and soluble adhesion molecules as possible prognostic markers of the efficacy of antiviral treatment in chronic hepatitis C

    Institute of Scientific and Technical Information of China (English)

    Anatol Panasiuk; Danuta Prokopowicz; Bozena Panasiuk

    2004-01-01

    AIM: To explain the role of Monocyte chemotactic protein-1 (MCP-1) and soluble adhesion molecules in chronic hepatitis C during the treatment of interferon alpha (IFNα) 2 b and ribavirin (RBV).METHODS: Concentrations of MCP-1, soluble adhesion molecules intercellular adhesion molecule-1 (sICAM-1), sPselectin, interleukin (IL) 6, and IL10 in serum were estimated in the group of 40 patients with chronic hepatitis C treated with IFNalpha2 b and RBV in 0, 16, 32, 48 wk of the therapy.RESULTS: In chronic hepatitis C, before and during the treatment, the serum levels of MCP-1 and sP-selectin in responders were similar to those of healthy subjects. In nonresponders (NR), MCP-1 increased in the course of IFNα+RBV treatment, differences were statistically significant as compared to responders. MCP-1 correlated statistically with the activity of pedportal inflammation (r = 0.35, P<0.05) but not with staging of liver fibrosis. sICAM-1 positively correlated with inflammatory activity and fibrosis in NR. sP-selectin did not correlate with histological findings in the liver. The MCP-1 correlated with the soluble form of sP-selectin concentrations (r = 6, P<0.001) and with IL-10 level in NR (r = 0.4, P<0.05). There was no correlation observed between the concentration of MCP-1 and sICAM-1, IL-6 during the treatment.CONCLUSION: MCP-1 concentration may be a prognostic marker of the efficacy of IFN+RBV therapy in patients with chronic hepatitis C.

  7. Real-time analysis of integrin-mediated chemotactic migration of T lymphocytes within 3-D extracellular matrix-like gels.

    Science.gov (United States)

    Franitza, S; Alon, R; Lider, O

    1999-05-27

    We have developed a novel 3-D gel reconstituted with major extracellular matrix (ECM) glycoproteins to follow the dynamics of migration of human T cells locomoting, in real-time, on gradients formed by representative chemoattractants: the C-C chemokine RANTES, and the pro-inflammatory cytokine IL-2. In the absence of chemoattractants, none of the T cells migrated directionally and the levels of random migration or cell polarization were low. However, major fractions of T cells placed in IL-2 and RANTES gradients in the gels polarized immediately after exposure to the chemoattractants. Shortly after polarization, 25% of the T cells migrated, in either a random or directional fashion, towards the sources of the chemoattractants; additional 5-10% of the cells remained polarized but stationary. The number of T cells migrating directionally towards RANTES or IL-2 peaked along with the formation of the chemotactic gradients. The directional migration of T cells was increased by a short pre-exposure to low doses of IL-2, which did not alter the level of expression of the beta1 integrins. The directional migration of T cells towards IL-2 and RANTES was mediated by IL-2R and pertussis toxin-sensitive receptors, respectively, and the directional, and to a lesser degree, the random locomotion of T cells induced by both chemoattractants required intact tyrosine kinase signaling and activities of the alpha4, alpha5, and, to a lesser degree, the alpha2 and alpha6 members the beta1 integrins. Our system enables the real-time tracking of individual locomoting lymphocytes and the analysis of their dynamic interactions with ECM components and cytokines. PMID:10365778

  8. Microfluidic study of the chemotactic response of Escherichia coli to amino acids, signaling molecules and secondary metabolites.

    Science.gov (United States)

    Nagy, Krisztina; Sipos, Orsolya; Valkai, Sándor; Gombai, Éva; Hodula, Orsolya; Kerényi, Ádám; Ormos, Pál; Galajda, Péter

    2015-07-01

    Quorum sensing and chemotaxis both affect bacterial behavior on the population level. Chemotaxis shapes the spatial distribution of cells, while quorum sensing realizes a cell-density dependent gene regulation. An interesting question is if these mechanisms interact on some level: Does quorum sensing, a density dependent process, affect cell density itself via chemotaxis? Since quorum sensing often spans across species, such a feedback mechanism may also exist between multiple species. We constructed a microfluidic platform to study these questions. A flow-free, stable linear chemical gradient is formed in our device within a few minutes that makes it suitable for sensitive testing of chemoeffectors: we showed that the amino acid lysine is a weak chemoattractant for Escherichia coli, while arginine is neutral. We studied the effect of quorum sensing signal molecules of Pseudomonas aeruginosa on E. coli chemotaxis. Our results show that N-(3-oxododecanoyl)-homoserine lactone (oxo-C12-HSL) and N-(butryl)-homoserine lactone (C4-HSL) are attractants. Furthermore, we tested the chemoeffector potential of pyocyanin and pyoverdine, secondary metabolites under a quorum sensing control. Pyocyanin is proved to be a weak attractant while pyoverdine are repellent. We demonstrated the usability of the device in co-culturing experiments, where we showed that various factors released by P. aeruginosa affect the dynamic spatial rearrangement of a neighboring E. coli population, while surface adhesion of the cells is also modulated. PMID:26339306

  9. Calcitonin gene-related peptide is a key factor in the homing of transplanted human MSCs to sites of spinal cord injury.

    Science.gov (United States)

    Zhang, Yu; Yang, Jinhua; Zhang, Peng; Liu, Tao; Xu, Jianwei; Fan, Zhihai; Shen, Yixin; Li, Wenjie; Zhang, Huanxiang

    2016-01-01

    Mesenchymal stem cells (MSCs) can be used to treat many diseases, including spinal cord injury (SCI). Treatment relies mostly on the precise navigation of cells to the injury site for rebuilding the damaged spinal cord. However, the key factors guiding MSCs to the epicenter of SCI remain unknown. Here, we demonstrated that calcitonin gene-related peptide (CGRP), a neural peptide synthesized in spinal cord, can dramatically aid the homing of human umbilical cord mesenchymal stem cells (HUMSCs) in spinal cord-transected SCI rats. First, HUMSCs exhibited chemotactic responses in vitro to CGRP. By time-lapse video analysis, increased chemotactic index (CMI), forward migration index (FMI) and speed contributed to this observed migration. Then, through enzyme immunoassay, higher CGRP concentrations at the lesion site were observed after injury. The release of CGRP directed HUMSCs to the injury site, which was suppressed by CGRP 8-37, a CGRP antagonist. We also verified that the PI3K/Akt and p38MAPK signaling pathways played a critical role in the CGRP-induced chemotactic migration of HUMSCs. Collectively, our data reveal that CGRP is a key chemokine that helps HUMSCs migrate to the lesion site and thereby can be used as a model molecule to study MSCs homing after SCI. PMID:27296555

  10. CCL7 is a protective factor secreted by mechanically loaded osteocytes.

    Science.gov (United States)

    Kitase, Y; Lee, S; Gluhak-Heinrich, J; Johnson, M L; Harris, S E; Bonewald, L F

    2014-11-01

    In a search for factors up-regulated by mechanical strain in osteocytes, we discovered that chemokine (C-C motif) ligand 7 (CCL7), a chemotactic myokine, was highly expressed in MLO-Y4 osteocyte-like cells. Although MLO-Y4 cells secrete potent chemotactic factors for osteoclast precursors, CCL7 was not responsible for this activity. CCL7 was increased in osteocytes in response to tooth movement in vivo. Since mechanical loading plays a crucial role in maintaining osteocyte viability, CCL7 was tested for protective activity and found to be protective against cell death induced by dexamethasone and etoposide. CCL7 specific antibody partially, but in combination with indomethacin, completely abrogated the protective effects of fluid flow shear stress against dexamethasone-induced cell death. CCL7 activated the β-catenin pathway through phosphorylation of glycogen synthase kinase 3 (GSK-3), suggesting that this pathway is responsible for the observed protective effects. A related cytokine, CCL2, also produced by MLO-Y4 cells but not regulated by mechanical loading, proved to be more potent and protected against cell death induced by not only dexamethasone, but also by Tumor Necrosis Factor α (TNFα). Whereas osteocytes may produce CCL2 in constitutively low levels, a major function of mechanically induced CCL7 may be to selectively protect osteocytes in an autocrine manner against glucocorticoid-induced cell death. PMID:25274752

  11. Chicken primordial germ cell motility in response to stem cell factor sensing.

    Science.gov (United States)

    Srihawong, Thanida; Kuwana, Takashi; Siripattarapravat, Kannika; Tirawattanawanich, Chanin

    2015-01-01

    Avian primordial germ cells (PGCs) are destined to migrate a long distance from their extra embryonic region via the vascular system to the gonadal ridges where they form the germ cells. Although PGC migration is crucial for a genetic continuation to the next generation, the factors and mechanisms that control their migration remain largely unknown. In the present study the chemotactic effect of stem cell factor (SCF) was examined on chicken blood circulating PGCs (cPGC), employing 3D chemotaxis slides and time-lapsed imaging analyses as an in vitro study model. Upon in vitro exposure to an SCF gradient, 77.1% (54 out of 70) of cPGCs showed a clear response, of which 48.1% (26 out of 54) polarized with the consecutive formation of a persistent membrane protrusion and significant directional migration towards the gradient and the others showed transient membrane protrusions. In contrast, the controls and apparently SCF unresponsive cPGCs and c-kit-negative red blood cells (RBCs) showed only cytoplasmic cycling with random formations of membrane blebbing and no directional migration. Significant (p goat anti-mouse c-kit primary antibody, suggesting that the cPGCs were capable of SCF sensing and the potential involvement of SCF/c-kit in the chemotactic migration. Therefore, SCF is suggested to function as a chemoattractant in the migration of chicken cPGC. PMID:26864485

  12. Angiogenic factors in relation to embryo implantation

    Directory of Open Access Journals (Sweden)

    Azadeh Bagheri

    2014-08-01

    Full Text Available Disturbances in uterine blood supply are associated with higher perinatal morbidity and mortality caused by preterm delivery, preeclampsia or intrauterine growth restriction. Adaptation of the uterine vasculature to the rising needs of the fetus occurs through both vasodilation and development of new vessels. Angiogenesis is the process of neovascularization from pre-existing blood vessels in response to hypoxic condition of tissues. The endometrium, decidua and placenta are rich sources of angiogenic growth factors. In general, the angiogenic process is initiated by growth factors such as VEGF, placental growth factor (PlGF or bFGF. Through a complex signal transduction machinery mediated by respective receptor-tyrosine kinases, an increase in the permeability of the maternal vessels is achieved to permit growth and invasion of endothelial cells. Their chemotactic migration, formation of a vessel lumen, and functional maturation of new capillaries complete the angiogenic process that involves the expression of specific adhesion receptors and extracellular matrix-degrading proteases. During vasculogenesis, endothelial progenitor cells--angioblasts--form a primitive vascular network. This process occurs mainly during fetal development, although recruitment of angioblasts from bone marrow and peripheral blood in response to ischemic insult have been described in adults. In this review article we have described a recent complication related to angiogenic involvement in embryo implantation. [Int J Reprod Contracept Obstet Gynecol 2014; 3(4.000: 872-879

  13. Control of human endometrial stromal cell motility by PDGF-BB, HB-EGF and trophoblast-secreted factors.

    Directory of Open Access Journals (Sweden)

    Maren Schwenke

    Full Text Available Human implantation involves extensive tissue remodeling at the fetal-maternal interface. It is becoming increasingly evident that not only trophoblast, but also decidualizing endometrial stromal cells are inherently motile and invasive, and likely contribute to the highly dynamic processes at the implantation site. The present study was undertaken to further characterize the mechanisms involved in the regulation of endometrial stromal cell motility and to identify trophoblast-derived factors that modulate migration. Among local growth factors known to be present at the time of implantation, heparin-binding epidermal growth factor-like growth factor (HB-EGF triggered chemotaxis (directed locomotion, whereas platelet-derived growth factor (PDGF-BB elicited both chemotaxis and chemokinesis (non-directed locomotion of endometrial stromal cells. Supernatants of the trophoblast cell line AC-1M88 and of first trimester villous explant cultures stimulated chemotaxis but not chemokinesis. Proteome profiling for cytokines and angiogenesis factors revealed neither PDGF-BB nor HB-EGF in conditioned media from trophoblast cells or villous explants, while placental growth factor, vascular endothelial growth factor and PDGF-AA were identified as prominent secretory products. Among these, only PDGF-AA triggered endometrial stromal cell chemotaxis. Neutralization of PDGF-AA in trophoblast conditioned media, however, did not diminish chemoattractant activity, suggesting the presence of additional trophoblast-derived chemotactic factors. Pathway inhibitor studies revealed ERK1/2, PI3 kinase/Akt and p38 signaling as relevant for chemotactic motility, whereas chemokinesis depended primarily on PI3 kinase/Akt activation. Both chemotaxis and chemokinesis were stimulated upon inhibition of Rho-associated, coiled-coil containing protein kinase. The chemotactic response to trophoblast secretions was not blunted by inhibition of isolated signaling cascades, indicating

  14. Stromal cell derived factor-1α (SDF-1α) directed chemoattraction of transiently CXCR4 overexpressing mesenchymal stem cells into functionalized three-dimensional biomimetic scaffolds

    DEFF Research Database (Denmark)

    Thieme, S; Ryser, Martin; Gentsch, Marcus;

    2009-01-01

    Three-dimensional (3D) bone substitute material should not only serve as scaffold in large bone defects but also attract mesenchymal stem cells, a subset of bone marrow stromal cells (BMSCs) that are able to form new bone tissue. An additional crucial step is to attract BMSCs from the surface...... into deeper structures of 3D porous bone substitute scaffolds. Here we show that transient overexpression of CXCR4 in human BMSCs induced by mRNA transfection enhances stromal cell-derived factor-1alpha (SDF-1alpha)-directed chemotactic capacity to invade internal compartments of porous 3D bone substitute...

  15. Suppression of Chemotactic Explosion by Mixing

    Science.gov (United States)

    Kiselev, Alexander; Xu, Xiaoqian

    2016-11-01

    Chemotaxis plays a crucial role in a variety of processes in biology and ecology. In many instances, processes involving chemical attraction take place in fluids. One of the most studied PDE models of chemotaxis is given by the Keller-Segel equation, which describes a population density of bacteria or mold which is attracted chemically to substance they secrete. Solutions of the Keller-Segel equation can exhibit dramatic collapsing behavior, where density concentrates positive mass in a measure zero region. A natural question is whether the presence of fluid flow can affect singularity formation by mixing the bacteria thus making concentration harder to achieve. In this paper, we consider the parabolic-elliptic Keller-Segel equation in two and three dimensions with an additional advection term modeling ambient fluid flow. We prove that for any initial data, there exist incompressible fluid flows such that the solution to the equation stays globally regular. On the other hand, it is well known that when the fluid flow is absent, there exists initial data leading to finite time blow up. Thus the presence of fluid flow can prevent the singularity formation. We discuss two classes of flows that have the explosion arresting property. Both classes are known as very efficient mixers. The first class are the relaxation enhancing (RE) flows of (Ann Math:643-674, 2008). These flows are stationary. The second class of flows are the Yao-Zlatos near-optimal mixing flows (Mixing and un-mixing by incompressible flows. arXiv:1407.4163, 2014), which are time dependent. The proof is based on the nonlinear version of the relaxation enhancement construction of (Ann Math:643-674, 2008), and on some variations of the global regularity estimate for the Keller-Segel model.

  16. Chemotactic Signaling by Single-Chain Chemoreceptors.

    Directory of Open Access Journals (Sweden)

    Patricia Mowery

    Full Text Available Bacterial chemoreceptors of the methyl-accepting chemotaxis protein (MCP family operate in commingled clusters that enable cells to detect and track environmental chemical gradients with high sensitivity and precision. MCP homodimers of different detection specificities form mixed trimers of dimers that facilitate inter-receptor communication in core signaling complexes, which in turn assemble into a large signaling network. The two subunits of each homodimeric receptor molecule occupy different locations in the core complexes. One subunit participates in trimer-stabilizing interactions at the trimer axis, the other lies on the periphery of the trimer, where it can interact with two cytoplasmic proteins: CheA, a signaling autokinase, and CheW, which couples CheA activity to receptor control. As a possible tool for independently manipulating receptor subunits in these two structural environments, we constructed and characterized fused genes for the E. coli serine chemoreceptor Tsr that encoded single-chain receptor molecules in which the C-terminus of the first Tsr subunit was covalently connected to the N-terminus of the second with a polypeptide linker. We showed with soft agar assays and with a FRET-based in vivo CheA kinase assay that single-chain Tsr~Tsr molecules could promote serine sensing and chemotaxis responses. The length of the connection between the joined subunits was critical. Linkers nine residues or shorter locked the receptor in a kinase-on state, most likely by distorting the native structure of the receptor HAMP domain. Linkers 22 or more residues in length permitted near-normal Tsr function. Few single-chain molecules were found as monomer-sized proteolytic fragments in cells, indicating that covalently joined receptor subunits were responsible for mediating the signaling responses we observed. However, cysteine-directed crosslinking, spoiling by dominant-negative Tsr subunits, and rearrangement of ligand-binding site lesions revealed subunit swapping interactions that will need to be taken into account in experimental applications of single-chain chemoreceptors.

  17. Profiling Signaling Polarity in Chemotactic Cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yingchun; Ding, Shi-Jian; Wang, Wei; Jacobs, Jon M.; Qian, Weijun; Moore, Ronald J.; Yang, Feng; Camp, David G.; Smith, Richard D.; Klemke, Richard L.

    2007-05-15

    While directional movement requires morphological polarization characterized by formation of a leading pseudopodium at the front and a trailing rear at the back, little is known about how protein networks are spatially integrated to regulate this process. Here, we utilize a unique pseudopodial purification system and quantitative proteomics and phosphoproteomics to map the spatial relationship of 3509 proteins and 228 distinct sites of phosphorylation in polarized cells. Networks of signaling proteins, metabolic pathways, actin regulatory proteins, and kinase-substrate cascades were found to partition to different poles of the cell including components of the Ras/ERK pathway. Also, several novel proteins were found to be differentially phosphorylated at the front or rear of polarized cells and to localize to distinct subcellular structures. Our findings provide insight into the spatial organization of signaling networks that control cell movement and provide a comprehensive profile of proteins and their sites of phosphorylation that control cell polarization.

  18. Suppression of Chemotactic Explosion by Mixing

    Science.gov (United States)

    Kiselev, Alexander; Xu, Xiaoqian

    2016-06-01

    Chemotaxis plays a crucial role in a variety of processes in biology and ecology. In many instances, processes involving chemical attraction take place in fluids. One of the most studied PDE models of chemotaxis is given by the Keller-Segel equation, which describes a population density of bacteria or mold which is attracted chemically to substance they secrete. Solutions of the Keller-Segel equation can exhibit dramatic collapsing behavior, where density concentrates positive mass in a measure zero region. A natural question is whether the presence of fluid flow can affect singularity formation by mixing the bacteria thus making concentration harder to achieve. In this paper, we consider the parabolic-elliptic Keller-Segel equation in two and three dimensions with an additional advection term modeling ambient fluid flow. We prove that for any initial data, there exist incompressible fluid flows such that the solution to the equation stays globally regular. On the other hand, it is well known that when the fluid flow is absent, there exists initial data leading to finite time blow up. Thus the presence of fluid flow can prevent the singularity formation. We discuss two classes of flows that have the explosion arresting property. Both classes are known as very efficient mixers. The first class are the relaxation enhancing (RE) flows of (Ann Math:643-674, 2008). These flows are stationary. The second class of flows are the Yao-Zlatos near-optimal mixing flows (Mixing and un-mixing by incompressible flows. arXiv:1407.4163, 2014), which are time dependent. The proof is based on the nonlinear version of the relaxation enhancement construction of (Ann Math:643-674, 2008), and on some variations of the global regularity estimate for the Keller-Segel model.

  19. Mixture Theory Study of Role of Growth Factor Gradients on Breast Cancer Chemotaxis

    Science.gov (United States)

    Chakraborty, Sreyashi; Schuff, Mary; Voigt, Elizabeth; Nauman, Eric; Rylander, Marissa; Vlachos, Pavlos

    2014-11-01

    The transport of chemotactic agents is strongly influenced by variation in interstitial flows in different types of tissue. The mixture theory model of the fluid and solute transport in the microvasculature of tissues accounts for transport in the vessel lumen, vessel wall and the interstitial space separately. In the present study we use this model to develop a three dimensional geometry of the tumor microenvironment platform incorporating a physiological concentration of growth factor protein through blood flow in an extracellular collagen matrix. We quantify chemotaxis in response to solute gradients of varying magnitude formed by diffusion of proteins into the surrounding collagen. The numerical analysis delineates the dependence of hydraulic permeability coefficient on solute concentration. The preliminary results show the existence of a linear concentration gradient in the central plane between the micro-channels and a strong nonlinear gradient at the remaining parts of the system.

  20. Relations of nuclear factor-kappa B activity in the kidney of children with primary nephrotic syndrome to clinical manifestations, pathological types, and urinary protein excretion

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hong-yang; SUN Ruo-peng; DONG Jun-hua; ZHEN Jun-hui

    2005-01-01

    @@ The pathogenesis of childhood primary nephrotic syndrome (PNS) is unclear. However, an immune mechanism has generally been accepted as a cause. Imbalance of T lymphocyte and a variety of inflammatory cytokines, chemotactic and transcription factors are involved in the pathophysiology and manifestations of PNS,1,2 and nuclear factor kappa B (NF-κB) transcriptionally regulates the expression of these factors.3 Research has been focused on NF-κB and inflammatory regulated mediators of renal diseases, but seldom on different clinical manifestations and histopathological changes. In order to explore a potential mechanism for the pathogenesis of PNS in children and a basis for preventing its advance, we determined NF-κB activity in the kidney of children with PNS in vitro using immunohistochemical staining and the multimedia coloured pathological image analysis system and its relations to clinical manifestations, histopathological changes and 24-hour urinary protein excretion.

  1. 脑缺血发生后 IP-10趋化 NK 细胞通过血脑屏障%Chemotactic effect of IP-10 to natural killer cells getting through blood brain barrier after cerebral ischemia

    Institute of Scientific and Technical Information of China (English)

    张瑶; 冯涛; 祝鸿雁; 王广友; 王丹丹; 李呼伦

    2014-01-01

    Objective To research the chemotactic effect of IP-10 on natural killer cells after cerebral ischemia .Methods Experiments in vivo: NK infiltration and IP-10 and CXCR3 ex-pression in pMCAO mouse brain were detected by immunofluorescence;NK infiltration in pM-CAO brains was detected by flowcytometry;IP-10 total expression level in brain were investiga-ted by RT-PCR.Experiments in vitro:Established blood brain barrier ( B.B.B.) in vitro;IP-10 expression of the supernatant from brain microvascular endothclial cell ( BMVEC ) and neu-ral cells after oxygen-gluoose depriuation ( OGD) were detected by ELISA; B.B.B.in vitro were separated into NK , NK+IP-10 blockade two groups , after OGD 6 h, NK cells migration counts were detected by flowcytometry;NK cells were cultured together with IP -10 ( 10 ng/mL), IP-10 (50 ng/mL), IP-10(100 ng/mL), then CXCR3 geomean.MFI value were de-tected by flowcytometry .Results Experiments in vivo:NK cells were found in pMCAO brain section and expressing CXCR 3 and IP-10; NK cells infiltration were higher in ischemia-hemi-sphere , and got a peak at 12 h ( P<0.05 );NK cells had anobviously increase by 12 h at in-filtration frequency (P<0.01 );IP-10 had a highest level at 12 h ( P<0.001 ) .Experiments in vitro:Neural cell had higher expression of IP-10 after OGD than BMVEC ( P <0.001 );Compared with group NK , group NK+IP-10 blockade had lower NK cells migration counts ( P<0.05 ) and permeability ( P<0.001 ) .Conclusion ①NK cells plays an important role dur-ing cerebral ischemia;②IP-10 can absorb NK cells across B .B.B.when ischemia happens by combined with its receptor CXCR 3 and has dose dependent .%目的:探讨脑缺血发生后 IP-10对NK细胞的趋化作用。方法体内实验:免疫荧光染色观察永久性大脑中动脉栓塞小鼠模型( pMCAO)脑组织中NK细胞浸润情况以及IP-10、CXCR3表达情况;流式细胞术检测pMCAO小鼠模型脑中NK细胞浸润数目;RT-PCR

  2. 幽门螺杆菌cheA和cheY基因表达及其产物与细菌趋化的相关性%Prokaryotic expression of Helicobacter pylori cheA and cheY genes and correlation among the expressed products and bacterial chemotactic behavior

    Institute of Scientific and Technical Information of China (English)

    吴盛海; 徐丽慧; 严杰; 王贤军

    2009-01-01

    目的 克隆幽门螺杆菌趋化相关基因cheA和they并构建其原核表达系统,建立幽门螺杆菌体外趋化模型并确定其趋化诱导物质,了解特异性抗体和氯氰碘柳胺对幽门螺杆菌趋化的抑制作用.方法 PCR扩增幽门螺杆菌NCTC11637株全长cheA和cheY基因片段,T-A克隆后测序.构建上述目的基因原核表达系统,采用SDS-PAGE和Bio-Rad凝胶成像分析系统检查目的重组蛋白rCheA和rCheY的表达情况,Ni-NTA亲和层析法提纯rCheA和rCheY.rCheA和rCheY免疫家兔获得抗血清,用饱和硫酸铵沉淀法和DEAE-32离子交换法提纯IsG,用免疫扩散法检测抗血清及其IsG效价.采用硬琼脂法建立幽门螺杆菌NCTC11637株体外趋化模型并检测11种物质的趋化诱导作用,同时分别观察抗rCheA IgG(rCheA-IgG)和氯氰碘柳胺钠对细菌趋化的抑制作用.结果 PCR扩增获得预期大小的cheA和cheY基因片段,其核苷酸和氨基酸序列与文献报道完全相同.所构建的原核表达系统能有效表达rCheA和rGheY.rCheA和rCheY兔抗血清及其IgG免疫扩散效价均分别为1:4和1:2.盐酸、硫酸和乙酸对该幽门螺杆菌均有趋化诱导作用,一定浓度的rCheA-IgG和氯氰碘柳胺钠均对幽门螺杆菌趋化有抑制作用(P<0.05).结论 本研究成功地构建了幽门螺杆菌NCTC11637株cheA和cheY基因原核表达系统.H~+是诱导幽门螺杆菌趋化的信号物质,rCheA-IgG和氯氰碘柳胺钠均能抑制幽门螺杆菌对H~+的趋化.%Objective To clone the cheA and cheY genes of Helicobacter pylori for construction of their prokaryotic expression systems, and to establish chemotactic model in vitro of H. pylori for determing chemotaxis-inducing substances and to understand the effects of specific antibody and closantel on inhibiting chemotactic behavior of the microbe. Methods The segments of entire cheA and cheY genes were amplified by PGR and then sequenced after T-A cloning. Prokaryotic expression systems of the

  3. Rapidly activated epidermal growth factor receptor mediates lipopolysaccharide-triggered migration of microglia.

    Science.gov (United States)

    Qu, Wen-Sheng; Liu, Jun-Li; Li, Chun-Yu; Li, Xiao; Xie, Min-Jie; Wang, Wei; Tian, Dai-Shi

    2015-11-01

    Previous reports have suggested that epidermal growth factor receptor (EGFR) is involved in microglia activation characterized by cell morphology changes, cytokine production and cell migration; and the biochemical regulation of the microglia migration is a potential therapeutic target following CNS inflammatory damages. However, the role of EGFR in microglia motility after inflammatory stimulation remains unknown. In the present study, lipopolysaccharide (LPS) was found to trigger rapid EGFR phosphorylation within 10 min, which was sustained during long-term stimulation in both primary microglial cells and the cultured BV2 microglial cells, furthermore, blocking EGFR phosphorylation by AG1478 significantly attenuated the LPS-induced chemotactic and chemokinetic migration of microglia. In addition, LPS could initiate calcium oscillation in microglia during live-cell recording, however, an intracellular calcium chelator and a selective inhibitor of calcium/calmodulin-dependent protein kinase II, but not an extracellular calcium chelator, remarkably suppressed the LPS-induced EGFR phosphorylation in BV2 microglia cells. As EGFR is not a traditional receptor for LPS, these findings suggest that the rapid phosphorylation of EGFR is attributed to the LPS-triggered intracellular calcium mobilization. By examining the downstream signals of EGFR, we further proved that extracellular signal-regulated kinase (ERK) is essential for EGFR-mediated microglia migration, because ERK inhibition attenuated the chemotactic and chemokinetic migration of microglia that had been induced by either LPS or EGF. Collectively, these results suggest that LPS could trigger the rapid phosphorylation of EGFR and subsequent ERK activation through mobilizing calcium activity, which underlies the microglia migration in an inflammatory condition.

  4. Allosteric Inhibition of Macrophage Migration Inhibitory Factor Revealed by Ibudilast

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Y.; Crichlow, G; Vermeire, J; Leng, L; Du, X; Hodsdon, M; Bucala, R; Cappello, M; Gross, M; et al.

    2010-01-01

    AV411 (ibudilast; 3-isobutyryl-2-isopropylpyrazolo-[1,5-a]pyridine) is an antiinflammatory drug that was initially developed for the treatment of bronchial asthma but which also has been used for cerebrovascular and ocular indications. It is a nonselective inhibitor of various phosphodiesterases (PDEs) and has varied antiinflammatory activity. More recently, AV411 has been studied as a possible therapeutic for the treatment of neuropathic pain and opioid withdrawal through its actions on glial cells. As described herein, the PDE inhibitor AV411 and its PDE-inhibition-compromised analog AV1013 inhibit the catalytic and chemotactic functions of the proinflammatory protein, macrophage migration inhibitory factor (MIF). Enzymatic analysis indicates that these compounds are noncompetitive inhibitors of the p-hydroxyphenylpyruvate (HPP) tautomerase activity of MIF and an allosteric binding site of AV411 and AV1013 is detected by NMR. The allosteric inhibition mechanism is further elucidated by X-ray crystallography based on the MIF/AV1013 binary and MIF/AV1013/HPP ternary complexes. In addition, our antibody experiments directed against MIF receptors indicate that CXCR2 is the major receptor for MIF-mediated chemotaxis of peripheral blood mononuclear cells.

  5. The nuclear factor-kappaB-interleukin-6 signalling pathway mediating vascular inflammation.

    Science.gov (United States)

    Brasier, Allan R

    2010-05-01

    Vascular inflammation is a common pathophysiological response to diverse cardiovascular disease processes, including atherosclerosis, myocardial infarction, congestive heart failure, and aortic aneurysms/dissection. Inflammation is an ordered process initiated by vascular injury that produces enhanced leucocyte adherence, chemotaxis, and finally activation in situ. This process is coordinated by local secretion of adhesion molecules, chemotactic factors, and cytokines whose expression is the result of vascular injury-induced signal transduction networks. A wide variety of mediators of the vascular injury response have been identified; these factors include vasoactive peptides (angiotensin II, Ang II), CD40 ligands, oxidized cholesterol, and advanced glycation end-products. Downstream, the nuclear factor-kappaB (NF-kappaB) transcription factor performs an important signal integration step, responding to mediators of vascular injury in a stimulus-dependent and cell type-specific manner. The ultimate consequence of NF-kappaB signalling is the activation of inflammatory genes including adhesion molecules and chemotaxins. However, clinically, the hallmark of vascular NF-kappaB activation is the production of interleukin-6 (IL-6), whose local role in vascular inflammation is relatively unknown. The recent elucidation for the role of the IL-6 signalling pathway in Ang II-induced vascular inflammation as one that controls monocyte activation as well as its diverse signalling mechanism will be reviewed. These new discoveries further our understanding for the important role of the NF-kappaB-IL-6 signalling pathway in the process of vascular inflammation. PMID:20202975

  6. CXC chemokine receptor 3 expression on CD34(+) hematopoietic progenitors from human cord blood induced by granulocyte-macrophage colony-stimulating factor

    DEFF Research Database (Denmark)

    Jinquan, T; Quan, S; Jacobi, H H;

    2000-01-01

    expressed on CD34(+) hematopoietic progenitors from human cord blood stimulated with granulocyte-macrophage colony-stimulating factor (GM-CSF) but not on freshly isolated CD34(+) progenitors. Freshly isolated CD34(+) progenitors expressed low levels of CXCR3 messenger RNA, but this expression was highly up......-induced CD34(+) progenitor chemotaxis. These chemotactic attracted CD34(+) progenitors are colony-forming units-granulocyte-macrophage. gamma IP-10 and Mig also induced GM-CSF-stimulated CD34(+) progenitor adhesion and aggregation by means of CXCR3, a finding confirmed by the observation that anti-CXCR3 m...... stimulated CXCR3 redistribution and cellular polarization in GM-CSF-stimulated CD34(+) progenitors. These results indicate that CXCR3-gamma IP-10 and CXCR3-Mig receptor-ligand pairs, as well as the effects of GM-CSF on them, may be especially important in the cytokine/chemokine environment...

  7. Effect of Serum and Oxygen Concentration on Gene Expression and Secretion of Paracrine Factors by Mesenchymal Stem Cells

    Directory of Open Access Journals (Sweden)

    Patrick Page

    2014-01-01

    Full Text Available Mesenchymal stem cells (MSC secrete paracrine factors that may exert a protective effect on the heart after coronary artery occlusion. This study was done to determine the effect of hypoxia and serum levels on the mRNA expression and secretion of paracrine factors. Mouse bone marrow MSC were cultured with 5% or 20% serum and in either normoxic (21% O2 or hypoxic (1% O2 conditions. Expression of mRNA for vascular endothelial growth factor (VEGF, monocyte chemotactic protein-1 (MCP-1, macrophage inflammatory protein-1α (MIP-1α, MIP-1β, and matrix metalloproteinase-2 (MMP-2 was determined by RT-qPCR. Secretion into the culture media was determined by ELISA. Hypoxia caused a reduction in gene expression for MCP-1 and an increase for VEGF (5% serum, MIP-1α, MIP-1β, and MMP-2. Serum reduction lowered gene expression for VEGF (normoxia, MCP-1 (hypoxia, MIP-1α (hypoxia, MIP-1β (hypoxia, and MMP-2 (hypoxia and increased gene expression for MMP-2 (normoxia. The level of secretion of these factors into the media generally paralleled gene expression with some exceptions. These data demonstrate that serum and oxygen levels have a significant effect on the gene expression and secretion of paracrine factors by MSC which will affect how MSC interact in vivo during myocardial ischemia.

  8. Organizational factors

    International Nuclear Information System (INIS)

    The following organizational factors are considered with respect to the human factor and operating safety of nuclear power plants: external influences; objectives and strategy; positions and ways of management; allocation of resources; working with human resources; operators' training; coordination of work; knowledge of organization and management; proceduralization of the topic; labour organizing culture; self-improvement system; and communication. (P.A.)

  9. Robust factorization

    DEFF Research Database (Denmark)

    Aanæs, Henrik; Fisker, Rune; Åström, Kalle;

    2002-01-01

    . These techniques and models enable the factorization scheme to deal effectively with mismatched features, missing features, and noise on the individual features. The proposed approach further includes a new method for Euclidean reconstruction that significantly improves convergence of the factorization algorithms......Factorization algorithms for recovering structure and motion from an image stream have many advantages, but they usually require a set of well-tracked features. Such a set is in generally not available in practical applications. There is thus a need for making factorization algorithms deal...... effectively with errors in the tracked features. We propose a new and computationally efficient algorithm for applying an arbitrary error function in the factorization scheme. This algorithm enables the use of robust statistical techniques and arbitrary noise models for the individual features...

  10. The ORF 113 of Heliocoverpa armigera Single Nucleopolyhedrovirus Encodes a Functional Fibroblast Growth Factor

    Institute of Scientific and Technical Information of China (English)

    Xiang LI; Chang-yong LIANG; Jian-hua SONG; Xin-wen CHEN

    2008-01-01

    Fibroblast growth factor (FGF) is a key regulator of developmental processes. A FGF homolog (vFGF) is found in all lepidopteran baculoviruses. Autographa californica nucleopolyhedrovirus (AcMNPV) and Bombyx mori NPV (BmNPV) vFGFs are chemotactic factors. Here we analyzed the vfgf of Helicoverpa armigera NPV (HearNPV), a group Ⅱ NPV. The HearNPV vfgftranscripts were detected from 18 to 96 h post-infection (hpi) of Hz-AMI cells with HearNPV and encoded a 36 kDa protein, which was secreted into the culture medium. HearNPV vFGF had strong affinity to heparin, a property important for FGF signaling via an FGF receptor. Unlike its AcMNPV homolog, HearNPV vFGF specially chemoattracted Hz-AM 1, but not other insect cells such as Sf9 and Se-UCR and not the mammalian cells 293 and HepG2. HearNPV vFGF is also associated with the envelope of BV but is absent in occlusion-derived virus, which coordinated to the chemotatic activity analysis.

  11. Glucose and acute exercise influence factors secreted by circulating angiogenic cells in vitro.

    Science.gov (United States)

    Witkowski, Sarah; Guhanarayan, Gayatri; Burgess, Rachel

    2016-02-01

    Circulating angiogenic cells (CAC) influence vascular repair through the secretion of proangiogenic factors and cytokines. While CAC are deficient in patients with diabetes and exercise has a beneficial effect on CACs, the impact of these factors on paracrine secretion from CAC is unknown. We aimed to determine whether the in vitro secretion of selected cytokines and nitric oxide (NO) from CAC is influenced by hyperglycemia and acute exercise. Colony-forming unit CAC (CFU-CAC) were cultured from young active men (n = 9, 24 ± 2 years) at rest and after exercise under normal (5 mmol/L) and elevated (15 mmol/L) glucose. Preliminary relative multiplex cytokine analysis revealed that CAC conditioned culture media contained three of six measured cytokines: transforming growth factor-beta-1 (TGFβ1), tumor necrosis factor alpha (TNFα), and monocyte chemotactic protein-1 (MCP-1). Single quantitative cytokine analysis was used to determine the concentration of each cytokine from the four conditions. NO was measured via Griess assay. There was a significant effect of CAC exposure to in vivo exercise on in vitro TGFβ1 secretion (P = 0.024) that was independent of glucose concentration. There was no effect of glucose or acute exercise on TNFα or MCP-1 concentration (both P > 0.05). The concentration of NO from CFU-CAC cultured in elevated glucose was lower following acute exercise (P = 0.002) suggesting that exercise did not maintain NO secretion under hyperglycemic conditions. Our results identify paracrine signaling factors that may be responsible for the proangiogenic function of CFU-CAC and an influence of acute exercise and elevated glucose on CFU-CAC soluble factor secretion. PMID:26847726

  12. An adipoinductive role of inflammation in adipose tissue engineering: key factors in the early development of engineered soft tissues.

    Science.gov (United States)

    Lilja, Heidi E; Morrison, Wayne A; Han, Xiao-Lian; Palmer, Jason; Taylor, Caroline; Tee, Richard; Möller, Andreas; Thompson, Erik W; Abberton, Keren M

    2013-05-15

    Tissue engineering and cell implantation therapies are gaining popularity because of their potential to repair and regenerate tissues and organs. To investigate the role of inflammatory cytokines in new tissue development in engineered tissues, we have characterized the nature and timing of cell populations forming new adipose tissue in a mouse tissue engineering chamber (TEC) and characterized the gene and protein expression of cytokines in the newly developing tissues. EGFP-labeled bone marrow transplant mice and MacGreen mice were implanted with TEC for periods ranging from 0.5 days to 6 weeks. Tissues were collected at various time points and assessed for cytokine expression through ELISA and mRNA analysis or labeled for specific cell populations in the TEC. Macrophage-derived factors, such as monocyte chemotactic protein-1 (MCP-1), appear to induce adipogenesis by recruiting macrophages and bone marrow-derived precursor cells to the TEC at early time points, with a second wave of nonbone marrow-derived progenitors. Gene expression analysis suggests that TNFα, LCN-2, and Interleukin 1β are important in early stages of neo-adipogenesis. Increasing platelet-derived growth factor and vascular endothelial cell growth factor expression at early time points correlates with preadipocyte proliferation and induction of angiogenesis. This study provides new information about key elements that are involved in early development of new adipose tissue.

  13. Competitiveness factors

    OpenAIRE

    Popa Liliana-Viorica

    2012-01-01

    Porter's theory supports the idea that, despite the globalization of production and trade, the competitive advantage is created in a national framework, nations, through their institutional, natural, cultural, economic characteristics ultimately determining the development of certain economic activities. The factors considered by Porter as determinants for the competitive advantage are grouped in four categories, the linkages between them being important as well

  14. Proliferative and inflammatory factors in the vitreous of patients with proliferative diabetic retinopathy

    Directory of Open Access Journals (Sweden)

    V V Chernykh

    2015-01-01

    Full Text Available Purpose: The purpose was to measure the concentrations of various cytokines and growth factors (including vascular endothelial growth factor [VEGF] and pigment epithelium-derived factor [PEDF] in the vitreous of patients with proliferative diabetic retinopathy (PDR and to investigate interaction between inflammatory and proliferative factors in the genesis of PDR. Materials and Methods : Vitreous samples from 32 eyes with PDR and 25 eyes without diabetes mellitus and signs of DR (control were collected. Vitreous concentrations of VEGF, PEDF, monocyte chemotactic protein-1 (MCP-1, interleukin-4 (IL-4, IL-6, IL-8, IL-10, IL-17A, and secretory immunoglobulin A (sIgA were simultaneously measured using enzyme-linked immunoassay. Results : Vitreous levels of VEGF, PEDF, IL-17A, IL-6, IL-8, IL-4, and sIgA were significantly (Π < 0.05 higher in eyes with PDR compared to control. The concentration of VEGF was more than 17-times higher than in control, and the concentration of PEDF was not changed oppositely and was also higher (1.45-times compared to control, that may indicate disturbances of compensatory mechanisms in angiogenesis regulation in PDR. Significant (Π < 0.05 positive correlations were observed between vitreous concentrations of VEGF and IL-17ΐ (r = 0.45, VEGF and IL-8 (r = 0.48, VEGF and IL-4 (r = 0.51, PEDF and IL-17ΐ (r = 0.48, PEDF and IL-8 (r = 0.59, MCP-1 and PEDF (r = 0.72, MCP-1 and IL-8 (r0 = 0.45, IL-4 and IL-17ΐ (r = 0.65, IL-4 and IL-8 (r = 0.71, IL-8 and IL-17ΐ (r = 0.59. Conclusions: Significantly raised levels of inflammatory and proliferative factors and numerous positive correlations between them may demonstrate a significant role of activation of vascular proliferation and local inflammation in the pathogenesis of PDR.

  15. Insights into the role of macrophage migration inhibitory factor in obesity and insulin resistance.

    LENUS (Irish Health Repository)

    Finucane, Orla M

    2012-11-01

    High-fat diet (HFD)-induced obesity has emerged as a state of chronic low-grade inflammation characterised by a progressive infiltration of immune cells, particularly macrophages, into obese adipose tissue. Adipose tissue macrophages (ATM) present immense plasticity. In early obesity, M2 anti-inflammatory macrophages acquire an M1 pro-inflammatory phenotype. Pro-inflammatory cytokines including TNF-α, IL-6 and IL-1β produced by M1 ATM exacerbate local inflammation promoting insulin resistance (IR), which consequently, can lead to type-2 diabetes mellitus (T2DM). However, the triggers responsible for ATM recruitment and activation are not fully understood. Adipose tissue-derived chemokines are significant players in driving ATM recruitment during obesity. Macrophage migration inhibitory factor (MIF), a chemokine-like inflammatory regulator, is enhanced during obesity and is directly associated with the degree of peripheral IR. This review focuses on the functional role of macrophages in obesity-induced IR and highlights the importance of the unique inflammatory cytokine MIF in propagating obesity-induced inflammation and IR. Given MIF chemotactic properties, MIF may be a primary candidate promoting ATM recruitment during obesity. Manipulating MIF inflammatory activities in obesity, using pharmacological agents or functional foods, may be therapeutically beneficial for the treatment and prevention of obesity-related metabolic diseases.

  16. Factor analysis

    CERN Document Server

    Gorsuch, Richard L

    2013-01-01

    Comprehensive and comprehensible, this classic covers the basic and advanced topics essential for using factor analysis as a scientific tool in psychology, education, sociology, and related areas. Emphasizing the usefulness of the techniques, it presents sufficient mathematical background for understanding and sufficient discussion of applications for effective use. This includes not only theory but also the empirical evaluations of the importance of mathematical distinctions for applied scientific analysis.

  17. Chemotactic response and adaptation dynamics in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Diana Clausznitzer

    2010-05-01

    Full Text Available Adaptation of the chemotaxis sensory pathway of the bacterium Escherichia coli is integral for detecting chemicals over a wide range of background concentrations, ultimately allowing cells to swim towards sources of attractant and away from repellents. Its biochemical mechanism based on methylation and demethylation of chemoreceptors has long been known. Despite the importance of adaptation for cell memory and behavior, the dynamics of adaptation are difficult to reconcile with current models of precise adaptation. Here, we follow time courses of signaling in response to concentration step changes of attractant using in vivo fluorescence resonance energy transfer measurements. Specifically, we use a condensed representation of adaptation time courses for efficient evaluation of different adaptation models. To quantitatively explain the data, we finally develop a dynamic model for signaling and adaptation based on the attractant flow in the experiment, signaling by cooperative receptor complexes, and multiple layers of feedback regulation for adaptation. We experimentally confirm the predicted effects of changing the enzyme-expression level and bypassing the negative feedback for demethylation. Our data analysis suggests significant imprecision in adaptation for large additions. Furthermore, our model predicts highly regulated, ultrafast adaptation in response to removal of attractant, which may be useful for fast reorientation of the cell and noise reduction in adaptation.

  18. Exploring the chemotactic attraction of Campylobacter jejuni in chicken colonization

    DEFF Research Database (Denmark)

    Vegge, Christina Skovgaard; Brøndsted, Lone; Ingmer, Hanne

    Campylobacter jejuni is the primary food borne bacterial pathogen in the developed world. The most important reservoir for C. jejuni is the gut of chickens, which are colonized commensally and efficiently by this organism. Predominantly the mucus filled crypts of the lower gastrointestinal tract...... are found to be colonized by C. jejuni, and the bacteria are expected to be attracted to this particular environment by chemotaxis. In order to explore the role of chemotaxis in C. jejuni colonization we are construction deletion mutants in the putative chemoreceptors of the sequenced strain NCTC11168...

  19. Steady-State Chemotactic Response in E. coli

    CERN Document Server

    Kafri, Yariv

    2007-01-01

    The bacterium E. coli maneuvers itself to regions with high chemoattractant concentrations by performing two stereotypical moves: `runs', in which it moves in near straight lines, and `tumbles', in which it does not advance but changes direction randomly. The duration of each move is stochastic and depends upon the chemoattractant concentration experienced in the recent past. We relate this stochastic behavior to the steady-state density of a bacterium population, and we derive the latter as a function of chemoattractant concentration. In contrast to earlier treatments, here we account for the effects of temporal correlations and variable tumbling durations. A range of behaviors obtains, that depends subtly upon several aspects of the system - memory, correlation, and tumbling stochasticity in particular.

  20. Controlling Interneuron Activity in Caenorhabditis Elegans to Evoke Chemotactic Behaviour

    OpenAIRE

    Kocabas, Askin; Shen, Ching-Han; Guo, Zengcai V.; Ramanathan, Sharad

    2012-01-01

    Animals locate and track chemoattractive gradients in the environment to find food. With its small nervous system, Caenorhabditis elegans is a good model system in which to understand how the dynamics of neural activity control this search behaviour. Extensive work on the nematode has identified the neurons that are necessary for the different locomotory behaviours underlying chemotaxis through the use of laser ablation, activity recording in immobilized animals and the study of mutants. Howe...

  1. Chemotactic peptide analogues. Synthesis and chemotactic activity of N-formyl-Met-Leu-Phe analogues containing (S)-phenylalaninol derivatives.

    Science.gov (United States)

    Zecchini, G P; Paradisi, M P; Torrini, I; Spisani, S

    1995-09-01

    The synthesis and the biological activity towards human neutrophils of some N-formyl-Met-Leu-Phe-OMe analogues containing (S)-phenylalaninol (Pheol) or its derivatives in place of the native phenylalanine are reported. While the analogue containing Pheol (4) was found to be devoid of significant biological activity, its esters 3 and 5, although inactive as chemoattractants, are able to strongly stimulate superoxide production and are active with a lower efficacy in the lysozyme release. PMID:7487425

  2. Malignant Peripheral Nerve Sheath Tumor Invasion Requires Aberrantly Expressed Epidermal Growth Factor (EGF) Receptors and is Variably Enhanced by Multiple EGF Family Ligands

    Science.gov (United States)

    Byer, Stephanie J.; Brossier, Nicole M.; Peavler, Lafe T.; Eckert, Jenell M.; Watkins, Stacey; Roth, Kevin A.; Carroll, Steven L.

    2013-01-01

    Aberrant epidermal growth factor receptor (EGFR) expression promotes the pathogenesis of malignant peripheral nerve sheath tumors (MPNSTs), the most common malignancy associated with neurofibromatosis type 1, but the mechanisms by which EGFR expression promotes MPNST pathogenesis are poorly understood. We hypothesized that inappropriately expressed EGFRs promote MPNST invasion and found that these kinases are concentrated in MPNST invadopodia in vitro. EGFR knockdown inhibited the migration of unstimulated MPNST cells in vitro and exogenous EGF further enhanced MPNST migration in a substrate-specific manner, promoting migration on laminin and, to a lesser extent, collagen. Thus, in this setting, EGF acts as a chemotactic factor. We also found that the 7 known EGFR ligands (EGF, betacellulin, epiregulin, heparin-binding EGF, transforming growth factor α [TGFα], amphiregulin, and epigen) variably enhanced MPNST migration in a concentration-dependent manner, with TGFα being particularly potent. With the exception of epigen, these factors similarly promoted the migration of non-neoplastic Schwann cells. Although transcripts encoding all 7 EGFR ligands were detected in human MPNST cells and tumor tissues, only TGFα was consistently overexpressed and was found to colocalize with EGFR in situ. These data indicate that constitutive EGFR activation, potentially driven by autocrine or paracrine TGFα signaling, promotes the aggressive invasive behavior characteristic of MPNSTs. PMID:23399900

  3. 趋化因子CXCL-8趋化骨髓间充质干细胞迁移的体外效应%In vitro effects of chemotactic factor CXCL-8 on the migration of bone marrow mesenchymal stem cells

    Institute of Scientific and Technical Information of China (English)

    李兴泽; 孟庆海; 金澎; 袁鲁

    2009-01-01

    背景:早期研究表明趋化因子参与骨髓间充质干细胞的体外趋化,确定骨髓间充质干细胞体内迁移的分子机制,对其介导的细胞治疗中枢神经系统损伤和疾病有重要作用.目的:观察体外条件下趋化因子CXCL-8对大鼠骨髓间充质干细胞迁移的趋化作用.设计、时间及地点:细胞学体外观察,于2007-10/2008-06在青岛大学医学院附属医院脑血管病研究所完成.材料:纯种SPF级成年Wistar大鼠8只,由青岛市实验动物和动物实验中心提供.鼠重组趋化因子CXCL-8为Santa cruz 公司产品.方法:采用全骨髓法分离培养大鼠骨髓间充质干细胞,胰蛋白酶消化传代.取500μL趋化因子CXCL-8,加入含体积分数为0.5%胎牛血清的DMEM条件培养基,分别将质量浓度调整为5,50,250,500μg/L加到趋化板下层,对照组单纯添加DMEM条件培养基,以8μm孔径的聚碳酸酯膜覆盖.调整骨髓间充质干细胞浓度至1.5×109L-1,取100μL细胞悬液加到趋化板上层.为验证趋化因子CXCL-8作用的特异性,将经抗CXCR6多克隆抗体孵育12 h后的骨髓间充质干细胞加到趋化板上层,趋化因子CXCL-8加到趋化板下层.主要观察指标:骨髓间充质干细胞趋化因子受体CXCR1的表达,趋化因子CXCL-8对骨髓间充质干细胞体外趋化迁移作用及其特异性检测.结果:骨髓间充质干细胞趋化因子受体CXCRl呈阳性表达,位于细胞膜和细胞浆中,RT-PCR琼脂糖凝胶电泳后出现215 bp特异性扩增条带.与对照组比较,加入5~500 μg/L趋化因子CXCL-8后,骨髓间充质干细胞迁移数均明显增加(P<0.05).加入抗CXCR1多克隆抗体后,骨髓间充质干细胞迁移数较250μg/L趋化因子CXCL-8组明显减少(P<0.05).结论:体外条件下趋化因子CXCL-8在5~500μg/L质量浓度范围可趋化骨髓间充质干细胞迁移,封闭趋化因子受体CXCR1后其趋化迁移作用明显减弱.

  4. Use of autologous growth factors in lumbar spinal fusion.

    Science.gov (United States)

    Lowery, G L; Kulkarni, S; Pennisi, A E

    1999-08-01

    The results of spinal fusion, especially posteriorly above the lumbosacral junction, have been mixed. Autologous growth factor concentrate (AGF) prepared by ultraconcentration of platelets contains multiple growth factors having a chemotactic and mitogenic effect on mesenchymal stem cells and osteoblasts and may play a role in initiating bone healing. The purpose of this retrospective study is to review our results with AGF in lumbar spinal fusions. To date, AGF has been used in 39 patients having lumbar spinal fusion. The study group consisted of the first 19 consecutive cases to allow at least 6 months follow-up. The average follow-up was 13 months (range 6 to 18 months). Follow-up compliance was 91%. There were 7 men and 12 women. Average age was 52 years (range 30-72 years). Nine patients had prior back surgery. There were 8 smokers. AGF was used in posterior (n = 15) or anterior intradiscal (n = 4) fusions. AGF was used with autograft and coraline hydroxyapatite in all posterior fusions, and autograft, coral, and intradiscal spacer (carbon fiber spinal fusion cages or Synthes femoral ring) in intradiscal fusions. Posterior stabilization was used in all cases. Eight cases were single-level fusions, 6 were two-level, and 1 was a three-level fusion. Autologous iliac crest bone graft was taken in 14 cases and local autograft used in 5 cases. Posteriorly, a total of 23 levels were fused; of these, nine were at L5-S1, eight at L4-L5, five at L3-L4, and one at L2-L3. No impending pseudoarthroses were noted on plain radiographic examination at last follow-up visit. Solid fusion was confirmed in 3 patients having routine hardware removal, and in 2 patients who had surgery at an adjacent level. There was one posterior wound infection, which was managed without sequelae. When used as an adjunct to autograft, AGF offers theoretical advantages that need to be examined in controlled studies. Further study is necessary to determine whether coralline hydroxyapatite used as a

  5. Delphinidin, a dietary anthocyanidin, inhibits platelet-derived growth factor ligand/receptor (PDGF/PDGFR) signaling.

    Science.gov (United States)

    Lamy, Sylvie; Beaulieu, Edith; Labbé, David; Bédard, Valérie; Moghrabi, Albert; Barrette, Stéphane; Gingras, Denis; Béliveau, Richard

    2008-05-01

    Most cancers are dependent on the growth of tumor blood vessels and inhibition of tumor angiogenesis may thus provide an efficient strategy to retard or block tumor growth. Recently, tumor vascular targeting has expanded to include not only endothelial cells (ECs) but also smooth muscle cells (SMCs), which contribute to a mature and functional vasculature. We have reported previously that delphinidin, a major biologically active constituent of berries, inhibits the vascular endothelial growth factor-induced phosphorylation of vascular endothelial growth factor receptor-2 and blocks angiogenesis in vitro and in vivo. In the present study, we show that delphinidin also inhibits activation of the platelet-derived growth factor (PDGF)-BB receptor-beta [platelet-derived growth factor receptor-beta (PDGFR-beta)] in SMC and that this inhibition may contribute to its antitumor effect. The inhibitory effect of delphinidin on PDGFR-beta was very rapid and led to the inhibition of PDGF-BB-induced activation of extracellular signal-regulated kinase (ERK)-1/2 signaling and of the chemotactic motility of SMC, as well as the differentiation and stabilization of EC and SMC into capillary-like tubular structures in a three-dimensional coculture system. Using an anthocyan-rich extract of berries, we show that berry extracts were able to suppress the synergistic induction of vessel formation by basic fibroblast growth factor-2 and PDGF-BB in the mouse Matrigel plug assay. Oral administration of the berry extract also significantly retarded tumor growth in a lung carcinoma xenograft model. Taken together, these results provide new insight into the molecular mechanisms underlying the antiangiogenic activity of delphinidin that will be helpful for the development of dietary-based chemopreventive strategies. PMID:18339683

  6. Cell surface syndecan-1 contributes to binding and function of macrophage migration inhibitory factor (MIF) on epithelial tumor cells.

    Science.gov (United States)

    Pasqualon, Tobias; Lue, Hongqi; Groening, Sabine; Pruessmeyer, Jessica; Jahr, Holger; Denecke, Bernd; Bernhagen, Jürgen; Ludwig, Andreas

    2016-04-01

    Surface expressed proteoglycans mediate the binding of cytokines and chemokines to the cell surface and promote migration of various tumor cell types including epithelial tumor cells. We here demonstrate that binding of the chemokine-like inflammatory cytokine macrophage migration inhibitory factor (MIF) to epithelial lung and breast tumor cell lines A549 and MDA-MB231 is sensitive to enzymatic digestion of heparan sulphate chains and competitive inhibition with heparin. Moreover, MIF interaction with heparin was confirmed by chromatography and a structural comparison indicated a possible heparin binding site. These results suggested that proteoglycans carrying heparan sulphate chains are involved in MIF binding. Using shRNA-mediated gene silencing, we identified syndecan-1 as the predominant proteoglycan required for the interaction with MIF. MIF binding was decreased by induction of proteolytic shedding of syndecan-1, which could be prevented by inhibition of the metalloproteinases involved in this process. Finally, MIF induced the chemotactic migration of A549 cells, wound closure and invasion into matrigel without affecting cell proliferation. These MIF-induced responses were abrogated by heparin or by silencing of syndecan-1. Thus, our study indicates that syndecan-1 on epithelial tumor cells promotes MIF binding and MIF-mediated cell migration. This may represent a relevant mechanism through which MIF enhances tumor cell motility and metastasis.

  7. Modulation of neutrophil and monocyte function by recombinant human granulocyte macrophage colony-stimulating factor in patients with lymphoma.

    Science.gov (United States)

    Kharazmi, A; Nielsen, H; Hovgaard, D; Borregaard, N; Nissen, N I

    1991-04-01

    Granulocyte macrophage colony-stimulating factor (GM-CSF) has been shown to inhibit the chemotaxis and enhance the oxidative burst response of human neutrophils in vitro. The present study describes the effect of recombinant GM-CSF on the neutrophil and monocyte function in patients with lymphoma undergoing GM-CSF treatment. Patients with either Hodgkin's or non-Hodgkin's lymphoma were treated with various dosages (2-16 micrograms kg-1 body weight per day for 5 days) of rhGM-CSF by intravenous or subcutaneous route. Prior to and on day 5 of rhGM-CSF treatment, neutrophil and monocyte chemotaxis and chemiluminescence responses to f-Met-Leu-Phe, zymosan activated serum (ZAS) and opsonized zymosan (OZ) were determined. It was observed that chemotactic response of neutrophils to f-Met-Leu-Phe and ZAS was reduced, whereas the chemiluminescence response of both cell types to f-Met-Leu-Phe and zymosan was enhanced by up to 43-fold. rhGM-CSF treatment did not affect degranulation of the neutrophils as measured by release of vitamin B12 binding protein. Degree of modulation of neutrophil and monocyte function by rhGM-CSF was independent of rhGM-CSF dosages administered. These data suggest that phagocytic defence system may be enhanced by GM-CSF treatment and that this cytokine may be a useful therapeutic adjunct in compromised patients.

  8. Inhibition of nuclear factor of activated T-cells (NFAT suppresses accelerated atherosclerosis in diabetic mice.

    Directory of Open Access Journals (Sweden)

    Anna V Zetterqvist

    Full Text Available OBJECTIVE OF THE STUDY: Diabetic patients have a much more widespread and aggressive form of atherosclerosis and therefore, higher risk for myocardial infarction, peripheral vascular disease and stroke, but the molecular mechanisms leading to accelerated damage are still unclear. Recently, we showed that hyperglycemia activates the transcription factor NFAT in the arterial wall, inducing the expression of the pro-atherosclerotic protein osteopontin. Here we investigate whether NFAT activation may be a link between diabetes and atherogenesis. METHODOLOGY AND PRINCIPAL FINDINGS: Streptozotocin (STZ-induced diabetes in apolipoprotein E(-/- mice resulted in 2.2 fold increased aortic atherosclerosis and enhanced pro-inflammatory burden, as evidenced by elevated blood monocytes, endothelial activation- and inflammatory markers in aorta, and pro-inflammatory cytokines in plasma. In vivo treatment with the NFAT blocker A-285222 for 4 weeks completely inhibited the diabetes-induced aggravation of atherosclerosis, having no effect in non-diabetic mice. STZ-treated mice exhibited hyperglycemia and higher plasma cholesterol and triglycerides, but these were unaffected by A-285222. NFAT-dependent transcriptional activity was examined in aorta, spleen, thymus, brain, heart, liver and kidney, but only augmented in the aorta of diabetic mice. A-285222 completely blocked this diabetes-driven NFAT activation, but had no impact on the other organs or on splenocyte proliferation or cytokine secretion, ruling out systemic immunosuppression as the mechanism behind reduced atherosclerosis. Instead, NFAT inhibition effectively reduced IL-6, osteopontin, monocyte chemotactic protein 1, intercellular adhesion molecule 1, CD68 and tissue factor expression in the arterial wall and lowered plasma IL-6 in diabetic mice. CONCLUSIONS: Targeting NFAT signaling may be a novel and attractive approach for the treatment of diabetic macrovascular complications.

  9. Priming of mononuclear cells with a combination of growth factors enhances wound healing via high angiogenic and engraftment capabilities.

    Science.gov (United States)

    Jin, Enze; Kim, Jong-Min; Kim, Sung-Whan

    2013-12-01

    Recently, we demonstrated that a specific combination of growth factors enhances the survival, adhesion and angiogenic potential of mononuclear cells (MNCs). In this study, we sought to investigate the changes of the angiogenic potential of MNCs after short-time priming with a specific combination of growth factors. MNCs were isolated using density gradient centrifugation and incubated with a priming cocktail containing epidermal growth factor (EGF), insulin-like growth factor (IGF)-1, fibroblast growth factor (FGF)-2, FMS-like tyrosine kinase (Flt)-3L , Angiopoietin (Ang)-1, granulocyte chemotactic protein (GCP)-2 and thrombopoietin (TPO) (all 400 ng/ml) for 15, 30 and 60 min. Wounds in nonobese diabetic-severe combined immune deficiency (NOD-SCID) mice were created by skin excision followed by cell transplantation. We performed a qRT-PCR analysis on the growth factor-primed cells. The angiogenic factors vascular endothelial growth factor (VEGF)-A, FGF-2, hepatocyte growth factor (HGF), platelet-derived growth factor (PDGF) and interleukin (IL)-8 and the anti-apoptotic factors IGF-1 and transforming growth factor-β1 were significantly elevated in the MNCs primed for 30 min. (T30) compared with the non-primed MNCs (T0). The scratch wound assay revealed that T30- conditioned media (CM) significantly increased the rate of fibroblast-mediated wound closure compared with the rates from T0-CM and human umbilical vein endothelial cells (HUVEC)-CM at 20 hrs. In vivo wound healing results revealed that the T30-treated wounds demonstrated accelerated wound healing at days 7 and 14 compared with those treated with T0. The histological analyses demonstrated that the number of engrafted cells and transdifferentiated keratinocytes in the wounds were significantly higher in the T30-transplanted group than in the T0-transplanted group. In conclusion, this study suggests that short-term priming of MNCs with growth factors might be alternative therapeutic option for cell

  10. 球形脂联素抑制高糖环境下肾小管上皮细胞单核趋化蛋白-1的高表达%Global adiponectin suppress the high expression of monocyte chemotactic protein-1 induced by high glucose in NRK52E cells

    Institute of Scientific and Technical Information of China (English)

    姚涛; 吴小燕; 於文丽; 高苹; 吴屹哲

    2015-01-01

    Objective To investigate the effect of globular adiponectin on the high expression of monocyte chemotactic protein-1 (MCP-1) induced by high glucose in rat renal tubular epithelial cells (NRK52E),and its relationship with adiponectin receptors and p38MAPK.Methods NRK52E cells were cultured in vitro and divided into six groups:normal glucose group (NG,5.6 mmol/L glucose),high glucose group(HG,25 mmol/L glucose),gAd groupl (HG+gAd 2 mg/L),gAd group2 (HG+gAd 5 mg/L),gAd group3 (HG+gAd 10 mg/L),p38MAPK antagonist group:(SB,HG+SB203580 10 μmol/L).The protein expression of phosphorylated p38MAPK (p-p38MAPK),total p38MAPK (t-p38MAPK),MCP-1 and AdipoR1/AdipoR2 were examined by western blotting.The mRNA expression of MCP-1 and AdipoR1/AdipoR2 were detected by RT-PCR and real-time PCR respectively.Results Compared with NG group,the mRNA and protein expression of MCP-1 increased significantly in HG group (all P< 0.05).The phosphorylation of p38MAPK increased (P< 0.05) with no change in t-p38MAPK protein.The addition of gAd or SB203580 inhibited the unregulation of MCP-1 and p-p38MAPK induced by HG.Two kinds of adipoR,adipoR1 and adipoR2,were all detectable in NG group,and mRNA and protein expression of adipoR1 was higher than that of adipoR2 (P< 0.01).Compared with NG group,the expression of adipoR decreased in HG group,but the difference had no statistical significance(P > 0.05).Compared to HG group,the mRNA and protein expression of adipoR1 increased in gAd groups (all P < 0.01).Conclusion The gAd can dose-dependently attenuate the overexpression of MCP-1 induced by high glucose,and this protective effect may be mediated by adipoR1 and p38MAPK.%目的 探讨高糖环境下球形脂联素(globular adiponectin,gAd)对大鼠近端肾小管上皮细胞(NRK-52E)单核趋化蛋白-1 (MCP-1)表达的影响以及其与脂联素受体(AdipoR)、p38丝裂原活化蛋白激酶(p38MAPK)的关系.方法 体外培养NRK-52E细胞,分为六组:正常对照组(NG,5.6 mmol

  11. Protein kinase A regulates 3-phosphatidylinositide dynamics during platelet-derived growth factor-induced membrane ruffling and chemotaxis.

    Science.gov (United States)

    Deming, Paula B; Campbell, Shirley L; Baldor, Linda C; Howe, Alan K

    2008-12-12

    Spatial regulation of the cAMP-dependent protein kinase (PKA) is required for chemotaxis in fibroblasts; however, the mechanism(s) by which PKA regulates the cell migration machinery remain largely unknown. Here we report that one function of PKA during platelet-derived growth factor (PDGF)-induced chemotaxis was to promote membrane ruffling by regulating phosphatidylinositol 3,4,5-trisphosphate (PIP(3)) dynamics. Inhibition of PKA activity dramatically altered membrane dynamics and attenuated formation of peripheral membrane ruffles in response to PDGF. PKA inhibition also significantly decreased the number and size of PIP(3)-rich membrane ruffles in response to uniform stimulation and to gradients of PDGF. This ruffling defect was quantified using a newly developed method, based on computer vision edge-detection algorithms. PKA inhibition caused a marked attenuation in the bulk accumulation of PIP(3) following PDGF stimulation, without effects on PI3-kinase (PI3K) activity. The deficits in PIP(3) dynamics correlated with a significant inhibition of growth factor-induced membrane recruitment of endogenous Akt and Rac activation in PKA-inhibited cells. Simultaneous inhibition of PKA and Rac had an additive inhibitory effect on growth factor-induced ruffling dynamics. Conversely, the expression of a constitutively active Rac allele was able to rescue the defect in membrane ruffling and restore the localization of a fluorescent PIP(3) marker to membrane ruffles in PKA-inhibited cells, even in the absence of PI3K activity. These data demonstrate that, like Rac, PKA contributes to PIP(3) and membrane dynamics independently of direct regulation of PI3K activity and suggest that modulation of PIP(3)/3-phosphatidylinositol (3-PI) lipids represents a major target for PKA in the regulation of PDGF-induced chemotactic events.

  12. Chemokine-like factor 1, a novel cytokine, contributes to airway damage, remodeling and pulmonary fibrosis

    Institute of Scientific and Technical Information of China (English)

    谭亚夏; 韩文玲; 陈英玉; 欧阳能太; 唐岩; 李枫; 丁培国; 任筱兰; 曾广翘; 丁静; 朱彤; 马大龙; 钟南山

    2004-01-01

    Background Chemokine-like factor 1 (CKLF1) was recently identified as a novel cytokine. The full-length CKLF1 cDNA contains 530 bp encoding 99 amino acid residues with a CC motif similar to that of other CC family chemokines. Recombinant CKLF1 exhibits chemotactic activity on leucocytes and stimulates proliferation of murine skeletal muscle cells. We questioned whether CKLF1 could be involved in the pathogenesis of inflammation and proliferation in the lung. Therefore we used efficient in vivo gene delivery method to investigate the biological effect of CKLF1 in the murine lung.Methods CKLF1-expressing plasmid, pCDI-CKLF1, was constructed and injected into the skeletal muscles followed by electroporation. Lung tissues were obtained at the end of week 1,2,3 and 4 respectively after injection. The pathological changes in the lungs were observed by light microscope.Results A single intramuscular injection of CKLF1 plasmid DNA into BALB/c mice caused dramatic pathological changes in the lungs of treated mice. These changes included peribronchial leukocyte infiltration, epithelial shedding, collagen deposition, proliferation of bronchial smooth muscle cells and fibrosis of the lung. Conclusions The sustained morphological abnormalities of the bronchial and bronchiolar wall, the acute pneumonitis and interstitial pulmonary fibrosis induced by CKLF1 were similar to phenomena observed in chronic persistent asthma, acute respiratory distress syndrome and severe acute respiratory syndrome. These data suggest that CKLF1 may play an important role in the pathogenesis of these important diseases and the study also implies that gene electro-transfer in vivo could serve as a valuable approach for evaluating the function of a novel gene in animals.

  13. Extracellular matrix is a source of mitogenically active platelet-derived growth factor.

    Science.gov (United States)

    Field, S L; Khachigian, L M; Sleigh, M J; Yang, G; Vandermark, S E; Hogg, P J; Chesterman, C N

    1996-08-01

    Platelet-derived growth factor (PDGF) is a chemotactic and mitogenic agent for fibroblasts and smooth muscle cells and plays a key role in the development of atherosclerotic lesions. PDGF is produced by a number of normal and transformed cell types and occurs as homo- or heterodimers of A and B polypeptide chains. Using Chinese hamster ovary (CHO) cells transfected with various forms of PDGF, we have previously shown that PDGF A(s) (short splice version) is secreted, PDGF A(l) (long splice version) predominantly extracellular matrix-associated, and PDGF B divided between medium, cells, and matrix. In the present study we have demonstrated the mitogenic activity of matrix-localized PDGF in artificial and more physiologically relevant models by culturing Balb/c-3T3 cells (3T3), human foreskin fibroblasts (HFF), and rabbit aortic smooth muscle cells (SMC) on extracellular matrix (ECM) laid down by PDGF-expressing CHO cells and human umbilical vein endothelial cells (HUVEC). These cells responded to the local growth stimulus of PDGF-containing CHO ECM and HUVEC ECM. We showed that 3T3 cells required proteolytic activity to utilize matrix-localized PDGF, as aprotinin and epsilon-ACA inhibited growth and 3T3 cells were shown to possess plasminogen activator activity. HFF and SMC did not appear to require proteolytic activity (including metalloproteinase and serine protease activity) as a prerequisite for mitogenesis but were able to access immobilized PDGF by contact with the matrix. An understanding of the mechanisms whereby the utilization of stored PDGF is controlled in situations of excessive cellular proliferation will aid in the development of therapy for these conditions. PMID:8707868

  14. SP600125对1型糖尿病小鼠颈动脉内皮功能及单核细胞趋化蛋白1表达的影响%The Effect of SP600125 on Endothelial Function and Monocyte Chemotactic Protein-1 Expression in Carotid Artery in Type 1 Diabetic Mice

    Institute of Scientific and Technical Information of China (English)

    王启章; 陈茂刚; 李达文; 刘朝来; 徐格林; 刘新峰

    2011-01-01

    Aim The incidence of stroke in diabetes is increasing seriously, which is associated with endothelial dysfunction and increased inflammation in carotid artery.Our study is to investigate the effect of c-Jun arnino-terminal ki-nase (JNK) specific inhibitor SP600125 on carotid endothelial function and monocyte chemotactic protein-1 (MCP-1) expression in type 1 diabetes. Methods Animals were divided into five groups in this study. The 1st group was C57BL/6 wild type male mice; the 2nd group was INS2AKUTI male mice, intraperitoneal injection with 0. 9% normal saline (NS) each day for 8 weeks; the 3rd, 4th, 5th group were INS2AKITA male mice, intraperitoneal injection with SP600125 10 mg/kg, 20 mg/kg, 30 mg/kg respectively each day for consecutive 8 weeks. Then the mice were killed and sreum my-eloperoxidase (MPO) , malondialdehyde (MDA) , nitric oxide (NO) , total nitric oxide synthase (TNOS) were measured. HE staining was performed in carotid artery and immunohistochemistry was performed to investigate MCP-1 protein expression in endothelial cells of carotid artery. P-JNK, JNK, MCP-1 protein expression in carotid artery was measured by Western blot, signal transducer and activator of transcription-1 (STAT-1) DNA binding activity was assayed by electro-phoretic mobility shift assay (EMSA). Results Compared with wild type mice, serum MPO and MDA expression increased prominently (P <0. 05) , whereas TNOS, NO decreased and p-JNK/JNK, MCP-1 expression increased significantly in INS2AKITA mice (P<0.05); STAT-1 DNA binding activity increased prominently in type 1 diabetic group compared with that in control group (P <0. 05). Compared with type 1 diabetic mice, after treatment with SP600125, MPO decreased and NO, TNOS increased and p-JNK/JNK, endothelial MCP-1 expression decreased (P<0. 05). The effects of SP600125 on MPO, NO, TNOS, MCP-1 were increased accordingly as the dose of SP600125 increased. As the dose of SP600125 increased, MCP-1 protein expression decreased 21. 82

  15. Molecular mechanisms and dynamic simulations of bipolarization of chemotactic cells%运动细胞初始极化阶段胞内信号分子双向积聚的分子机制及动态数值模拟

    Institute of Scientific and Technical Information of China (English)

    冯世亮; 朱卫平

    2012-01-01

    cells, such as Dictyostelium and Leukocyte, are chemotactic. As a response of the cell to extracellular attractants that spread from the front, a bidirectional material movement occurs in the cell: an enzyme PI3K and its product PI(3,4,5)P3 (Phosphatidylinositol 3,4,5-trisphosphate) in plasma membrane diffuse forward and aggregate in the front edge, while PTEN (A degrading enzyme of PI(3,4,5)P3) and its product PI(4,5)P2 (Phosphatidylinositol 4,5-bisphosphate) run in the opposite way, which forms a bipolarization. To interpret this bipolarization phenomenon, a mathematic model was constructed based on the principle of "local excitation and global inhibitation" as well as the mechanism of positive/negative feedback in signal transduction. The activated Rac was employed as a trigger signal, and the evolution of PI(3,4,5)P3 and PI(4,5)P2 along with the activation and inhibitation of enzymes (i.e., PI3K, PTEN) was described by a set of coupled transient diffusion-reaction equations, being simulated by a lattice Boltzmann method. The source terms in the diffusion-reaction equations include the stochastic interactions between the intracellular signalation molecules (i.e., PI3K, PI(3,4,5)P3), being simulated by a Monte-Carlo method according to the Michaelis-Menten catalytic kinetics. The simulation results show that the bipolarization is governed by a short-range positive feedback loop: Rac→PI3K(→)PI(3,4,5)P3, and a long-range negative feedback loop: PI(3,4,5)P3 (→) PTEN→PI(4,5)P2, which is a presentation of "local excitation and global inhabitation". In addition, it is found that the bipolarization rate is dependent on the total average concentration of PI3K or PTEN, and the optimum is 0.07 μmol/L for the rapidest bipolarization.

  16. Endometrial Cancer Risk Factors

    Science.gov (United States)

    ... cancer? Next Topic What causes endometrial cancer? Endometrial cancer risk factors A risk factor is anything that affects your ... to obesity, which is a well-known endometrial cancer risk factor. Many scientists think this is the main way ...

  17. Risk Factors and Prevention

    Science.gov (United States)

    ... Resources Risk Factors & Prevention Back to Patient Resources Risk Factors & Prevention Even people who look healthy and ... Blood Pressure , high cholesterol, diabetes, and thyroid disease. Risk Factors For Arrhythmias and Heart Disease The following ...

  18. Risk Factors for Scleroderma

    Science.gov (United States)

    ... You are here: Home For Patients Risk Factors Risk Factors for Scleroderma The cause of scleroderma is ... what biological factors contribute to scleroderma pathogenesis. Genetic Risk Scleroderma does not tend to run in families ...

  19. Electroweak form factors

    International Nuclear Information System (INIS)

    The present status of electroweak nucleon form factors and the N - Δ transition form factors is reviewed. Particularly the determination of dipole mass MA in the axial vector form factor is discussed

  20. Macrophage colony-stimulating factor (CSF-1) induces pro-inflammatory gene expression and enhances antimicrobial responses of goldfish (Carassius auratus L.) macrophages.

    Science.gov (United States)

    Grayfer, Leon; Hanington, Patrick C; Belosevic, Miodrag

    2009-03-01

    We report on the regulation of pro-inflammatory functions of goldfish macrophages and induction of gene expression by recombinant goldfish CSF-1 (rgCSF-1). Recombinant goldfish TNFalpha-2 (rg TNFalpha-2), rgIFNgamma but not rgTGFbeta induced time-dependent increase of CSF-1 expression in macrophages. Treatment of goldfish macrophages with rgCSF-1 increased expression of several immune genes including CXCL-8 (=IL-8), CCL-1, TNFalpha-1, TNFalpha-2, IL-1beta-1, IL-1beta-2, IL-12-p35, IL-12-p40, IFN, IL-10 and iNOS A and B. The rgCSF-1 treatment did not significantly alter the mRNA levels of TGFbeta and NRAMP in macrophages up to 48h post treatment. However, at 72h post treatment, the expression of TGFbeta increased whereas that of NRAMP decreased. The treatment of macrophages with rgCSF-1 enhanced their respiratory burst and nitric oxide responses that were abrogated after addition of soluble CSF-1 receptor (sCSF-1R) to cell cultures. Macrophages exhibited a concentration-dependent chemotactic response toward rgCSF-1 as well as an increase in phagocytic activity that was abrogated after addition of sCSF-1R to cell cultures. Our results indicate that in addition to being an important growth factor of goldfish macrophages, rgCSF-1 also plays a central role in the regulation of their pro-inflammatory responses. PMID:19130890

  1. Elevated platelet-derived growth factor-BB concentrations in premature neonates who develop chronic lung disease

    Directory of Open Access Journals (Sweden)

    Adcock Kim G

    2004-06-01

    Full Text Available Abstract Background Chronic lung disease (CLD in the preterm newborn is associated with inflammation and fibrosis. Platelet-derived growth factor-BB (PDGF-BB, a potent chemotactic growth factor, may mediate the fibrotic component of CLD. The objectives of this study were to determine if tracheal aspirate (TA concentrations of PDGF-BB increase the first 2 weeks of life in premature neonates undergoing mechanical ventilation for respiratory distress syndrome (RDS, its relationship to the development of CLD, pulmonary hemorrhage (PH and its relationship to airway colonization with Ureaplasma urealyticum (Uu. Methods Infants with a birth weight less than 1500 grams who required mechanical ventilation for RDS were enrolled into this study with parental consent. Tracheal aspirates were collected daily during clinically indicated suctioning. Uu cultures were performed on TA collected in the first week of life. TA supernatants were assayed for PDGF-BB and secretory component of IgA concentrations using ELISA techniques. Results Fifty premature neonates were enrolled into the study. Twenty-eight infants were oxygen dependent at 28 days of life and 16 infants were oxygen dependent at 36 weeks postconceptual age. PDGF-BB concentrations peaked between 4 and 6 days of life. Maximum PDGF-BB concentrations were significantly higher in infants who developed CLD or died from respiratory failure. PH was associated with increased risk of CLD and was associated with higher PDGF-BB concentrations. There was no correlation between maximum PDGF-BB concentrations and Uu isolation from the airway. Conclusions PDGF-BB concentrations increase in TAs of infants who undergo mechanical ventilation for RDS during the first 2 weeks of life and maximal concentrations are greater in those infants who subsequently develop CLD. Elevation in lung PDGF-BB may play a role in the development of CLD.

  2. MAC-1 Glycoprotein Family mediates adherence of neutrophils to endothelial cells stimulated by leukotriene B4 and platelet activating factor

    International Nuclear Information System (INIS)

    The process of neutrophil (N) adhesion to and migration through endothelium (EC), an early event in the induction of the acute inflammatory response, has been attributed to the generation of extravascular chemoattractant peptides and lipids. Although both leukotriene B4 (LTB4) and platelet activating factor (PAF) enhance N adherence to EC, the mechanisms involved in this interaction are still not completely understood. Since the MAC-1 Glycoprotein (GP) Family has recently been shown to be required for a variety of adherence-dependent functions of stimulated N, the authors questioned whether these adherence-associated GP might be involved in N adherence to EC stimulated by LTB4 or PAF. Using a microtiter adherence assay with 111In labeled N, they assessed the ability of N from patients with MAC-1, LFA-1 Deficiency to adhere to monolayers of human omental microvascular or umbilical vein EC as well as to serum-coated plastic. Patient N exhibited markedly diminished adherence in response to LTB4 or PAF compared to normal controls. LTB4 and PAF enhanced expression of the MAC-1 GP Family on the surface of normal N as determined by flow cytofluorimetry using a monoclonal antibody (TS1/18) to the GP common beta subunit. In addition TS1/18 (20 μg/ml) completely inhibited N adherence stimulated by either LTB4 (10-8M) or PAF(10-11M). Thus, the MAC-1 GP Family appears to be important in chemotactic factor regulation of N adherence to EC

  3. Higher levels of soluble Fas ligand and transforming growth factor-β after omalizumab treatment: a case report.

    Science.gov (United States)

    Kao, Shu-Ling; Yu, Hong-Ren; Kuo, Ho-Chang; Tsui, Ka-Yin; Wu, Chih-Chiang; Chang, Ling-Sai; Liang, Chi-Di; Chung, Yu-Hsiu; Yang, Kuender D

    2012-02-01

    A skewed T-helper (T(h))1/T(h)2 immune response is considered to be the major cause of allergic disorders. Overproduction of T(h)2 cytokines, which promote recruitment and activation of mast cells and eosinophils, plays a key part in the pathogenesis of allergic asthma. The mechanisms by which omalizumab is effective in asthma treatment are not yet fully understood. A 16-year-old girl who was experiencing frequent asthma attacks in spite of daily administration of budesonide (640 μg) and montelukast (10mg) was given omalizumab (375 mg) at intervals of 2 weeks, to prevent a visit to the emergency room. Plasma levels of T(h)1 cytokines [interferon (IFN)-γ and interleukin (IL)-12p70], T(h)2 cytokines (IL-4 and IL-13), other proinflammatory and regulatory cytokines [IL-6, IL-10, IL-17, tumor necrosis factor (TNF)-α, and transforming growth factor (TGF)-β], chemokines [monocyte chemotactic protein (MCP)-1, chemokine ligand (CCL)7, and CCL17], and soluble Fas ligand (sFasL) were measured before treatment and after treatment for 8 weeks. She showed a good clinical response to omalizumab: her lung function parameters improved and the use of β2-agonist decreased. No emergency room visits were required after omalizumab treatment for 8 weeks. Plasma levels of sFasL and TGF-β showed obvious increases after omalizumab therapy. IL-12p70 levels were decreased as compared to the corresponding baseline levels. These findings suggest that the effects of omalizumab in asthma treatment are not restricted to the regulation of the skewed T(h)1/T(h)2 cytokine immune response, and sFasL-mediated apoptosis and regulatory T-cell (Treg)-mediated TGF-β seem to have important roles in the therapeutic effects of omalizumab. PMID:22244736

  4. Effect of basic fibroblast growth factor on the proliferation, migration and phenotypic modulation of airway smooth muscle cells

    Institute of Scientific and Technical Information of China (English)

    ZOU Hui; NIE Xiu-hong; ZHANG Yi; HU Mu; ZHANG Yu Alex

    2008-01-01

    Background Proliferation,cell migration and phenotypic modulation of airway smooth muscle cells(ASMCs)are important features of airway remodelling in asthma.The precise cellular and molecular mechanisms that regulate ASMCs proliferation,migration and phenotypic modulation in the lung remain unknown.Basic fibroblast growth factor(bFGF),a highly specific chemotactic and mitogenic factor for many cell types,appears to be involved in the development of airway remodelling.Our study assessed whether bFGF directly stimulates the proliferation,migration and phenotypic modulation of ASMCs.Methods Confluent and growth arrested human ASMCs were treated with human recombinant FGF.Proliferation was measured by BrdU incorporation and cell counting.Migration was examined using Boyden chamber apparatus.Expressions of smooth muscle(sm)-α-actin and sm-myosin heavy chain(MHC)isoform 1 were determined by RT-PCR and Western blot analysis.Results It was found that hrbFGF(10 ng/ml),when added to ASMCs,induced a significant increase in BrdU uptake and cell number by ASMCS as compared to controls and a significant increase in ASMCs migration with respect to controls.The mRNA and protein expressions of sm-α-actin and sm-MHC in ASMCs that were stimulated with hrbFGF decreased with respect to controls.Conclusion It appears that bFGF can directly stimulate proliferation and migration of ASMCs.however,the expressions of cells'contractive phenotype decreased.

  5. SEVEN FACTORS OF SUCCESS

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    I don't believe that there is any one recipe for success. Instead, I believe success is the result of a combination of a lot of different factors. The more factors you have on your side, the more likely you are to succeed, and positive attitude is just one of those factors. Here are seven additional factors that are also important.

  6. Foundations of factor analysis

    CERN Document Server

    Mulaik, Stanley A

    2009-01-01

    Introduction Factor Analysis and Structural Theories Brief History of Factor Analysis as a Linear Model Example of Factor AnalysisMathematical Foundations for Factor Analysis Introduction Scalar AlgebraVectorsMatrix AlgebraDeterminants Treatment of Variables as Vectors Maxima and Minima of FunctionsComposite Variables and Linear Transformations Introduction Composite Variables Unweighted Composite VariablesDifferentially Weighted Composites Matrix EquationsMulti

  7. ISS Payload Human Factors

    Science.gov (United States)

    Ellenberger, Richard; Duvall, Laura; Dory, Jonathan

    2016-01-01

    The ISS Payload Human Factors Implementation Team (HFIT) is the Payload Developer's resource for Human Factors. HFIT is the interface between Payload Developers and ISS Payload Human Factors requirements in SSP 57000. ? HFIT provides recommendations on how to meet the Human Factors requirements and guidelines early in the design process. HFIT coordinates with the Payload Developer and Astronaut Office to find low cost solutions to Human Factors challenges for hardware operability issues.

  8. Evaluation of the survival of bone marrow-derived mononuclear cells and the growth factors produced upon intramedullary transplantation in rat models of acute spinal cord injury.

    Science.gov (United States)

    Arai, Kiyotaka; Harada, Yasuji; Tomiyama, Hiroyuki; Michishita, Masaki; Kanno, Nobuo; Yogo, Takuya; Suzuki, Yoshihisa; Hara, Yasushi

    2016-08-01

    Intramedullary bone marrow-derived mononuclear cell (BM-MNC) transplantation has demonstrated neuroprotective effects in the chronic stage of spinal cord injury (SCI). However, no previous study has evaluated its effects in the acute stage, even though cell death occurs mainly within 1week after injury in all neuronal cells. Moreover, the mechanism underlying these effects remains unclear. We aimed to investigate the survival of intramedullary transplanted allogeneic BM-MNCs and the production of growth factors after transplantation to clarify the therapeutic potential of intramedullary transplanted BM-MNCs and their protective effects in acute SCI. Sprague-Dawley rats were subjected to traumatic SCI and received intramedullary transplantation of EGFP(+)BM-MNCs (n=6), BM-MNCs (n=10), or solvent (n=10) immediately after injury. To evaluate the transplanted BM-MNCs and their therapeutic effects, immunohistochemical evaluations were performed at 3 and 7days post-injury (DPI). BM-MNCs were observed at the injected site at both 3 (683±83 cells/mm(2)) and 7 DPI (395±64 cells/mm(2)). The expression of hepatocyte growth factor was observed in approximately 20% transplanted BM-MNCs. Some BM-MNCs also expressed monocyte chemotactic protein-1 or vascular endothelial growth factor. The demyelinated area and number of cleaved caspase-3-positive cells were significantly smaller in the BM-MNC-transplanted group at 3 DPI. Hindlimb locomotor function was significantly improved in the BM-MNC-transplanted group at 7 DPI. These results suggest that intramedullary transplantation of BM-MNCs is an efficient method for introducing a large number of growth factor-producing cells that can induce neuroprotective effects in the acute stage of SCI. PMID:27473980

  9. Bayesian Exploratory Factor Analysis

    DEFF Research Database (Denmark)

    Conti, Gabriella; Frühwirth-Schnatter, Sylvia; Heckman, James J.;

    2014-01-01

    This paper develops and applies a Bayesian approach to Exploratory Factor Analysis that improves on ad hoc classical approaches. Our framework relies on dedicated factor models and simultaneously determines the number of factors, the allocation of each measurement to a unique factor, and the corr......This paper develops and applies a Bayesian approach to Exploratory Factor Analysis that improves on ad hoc classical approaches. Our framework relies on dedicated factor models and simultaneously determines the number of factors, the allocation of each measurement to a unique factor......, and the corresponding factor loadings. Classical identification criteria are applied and integrated into our Bayesian procedure to generate models that are stable and clearly interpretable. A Monte Carlo study confirms the validity of the approach. The method is used to produce interpretable low dimensional aggregates...

  10. Heart disease - risk factors

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000106.htm Heart disease - risk factors To use the sharing features on ... a certain health condition. Some risk factors for heart disease you cannot change, but some you can. Changing ...

  11. Factor VII deficiency

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/000548.htm Factor VII deficiency To use the sharing features on this page, please enable JavaScript. Factor VII (seven) deficiency is a disorder caused by a ...

  12. Annual Adjustment Factors

    Data.gov (United States)

    Department of Housing and Urban Development — The Department of Housing and Urban Development establishes the rent adjustment factors - called Annual Adjustment Factors (AAFs) - on the basis of Consumer Price...

  13. Risk Factors for Thrombosis

    Institute of Scientific and Technical Information of China (English)

    包承鑫

    2002-01-01

    @@ Thrombotic disease is a multifactorial disease, multiple interactions between genetic and environmental factors contribute to the development of the disease.This review summarized some risk factors reported for arterial thrombosis and venous thrombosis in recent few years.

  14. Factoring Polynomials and Fibonacci.

    Science.gov (United States)

    Schwartzman, Steven

    1986-01-01

    Discusses the factoring of polynomials and Fibonacci numbers, offering several challenges teachers can give students. For example, they can give students a polynomial containing large numbers and challenge them to factor it. (JN)

  15. Relative Expression of Apoptotic and Vascular Epithelial Growth Factor Receptor Genes in Gamma-Irradiated Rat Kidney

    International Nuclear Information System (INIS)

    Biological process of wound healing, which occurs in three phases of revascularization (inflammatory, proliferative, and maturation) is an important essential step in regulating this process. Blood vessels serve as carriers for various cells, cytokines, and growth factors that are needed for tissue repair. The formation of new blood vessels is a necessary event during embryogenesis, but it occurs rarely in the adult with few exceptions, such as in the female reproductive system and wound healing. Angiogenesis is controlled by a variety of mitogenic, chemotactic, and inhibitory peptide and lipid factors that act on invading endothelial and smooth muscle cells. One of the most important angiogenic factors is the vascular endothelial growth factor (VEGF), a glycosylated protein of 46-48 kD composed of two disulphide linked subunits. The VEGF family consists of six members, five splicing forms of VEGF and the placenta-derived growth factor (PDGF). In normal, VEGF is expressed during embryogenesis and in a limited number of sites in adults. In disease states, VEGF can be detected in various tumor cells, the synovial pannus in rheumatoid arthritis, and in keratinocytes during wound healing. Five different VEGF isoforms, with 121, 145, 165, 189, and 106 amino acids, can be generated as a result of an alternative splicing from the single VEGF gene. The VEGF molecules bind to receptors known as VEFGR- 1 (FLT-1, fms-like tyrosine kinase 1), VEGFR-2 (KDR, kinase domain region/FLK-1, fetal liver kinase 1), VEGFR-2 (FLT-4), neurophilin-1, neurophilin-2, and heparan sulfate proteoglycans. Ionizing radiation can affect the angiogenesis and neovascularization on normal tissues in radiotherapy or by background radiation surrounding living beings. Kidney belongs to the urinary system and classified to the radio-resistant organ according to the previous studies. Therefore, the present study tested the effect of gamma irradiation and mercury chloride (MgCl2) to the renal region by

  16. Human factors in training

    International Nuclear Information System (INIS)

    The Human Factors concept is a focused effort directed at those activities which require human involvement. Training is, by its nature, an activity totally dependent on the Human Factor. This paper identifies several concerns significant to training situations and discusses how Human Factor awareness can increase the quality of learning. Psychology in the training arena is applied Human Factors. Training is a method of communication represented by sender, medium, and receiver. Two-thirds of this communications model involves the human element directly

  17. Integer factorization algorithms

    OpenAIRE

    Bogataj, Polona

    2011-01-01

    The decomposition of a natural number into a product of prime numbers is called factorization. The main problem with factorization is the fact that there is no known efficient algorithm which would factor a given natural number n in polynomial time. The closest equivalent to such an algorithm is Shor's algorithm for quantum computers, which is still not practically applicable. The difficulties with factorization form the basis for modern cryptosystems—the most renowned among them is the RSA a...

  18. Factoring multivariate integral polynomials.

    OpenAIRE

    Lenstra, A.K.

    1983-01-01

    An algorithm is presented to factorize polynomials in several variables with integral coefficients that is polynomial-time in the degrees of the polynomial to be factored, for any fixed number of variables. The algorithm generalizes the algorithm presented by A. K. Lenstra et al. to factorize integral polynomials in one variable.

  19. Protein Kinase A Regulates 3-Phosphatidylinositide Dynamics during Platelet-derived Growth Factor-induced Membrane Ruffling and Chemotaxis*S⃞

    Science.gov (United States)

    Deming, Paula B.; Campbell, Shirley L.; Baldor, Linda C.; Howe, Alan K.

    2008-01-01

    Spatial regulation of the cAMP-dependent protein kinase (PKA) is required for chemotaxis in fibroblasts; however, the mechanism(s) by which PKA regulates the cell migration machinery remain largely unknown. Here we report that one function of PKA during platelet-derived growth factor (PDGF)-induced chemotaxis was to promote membrane ruffling by regulating phosphatidylinositol 3,4,5-trisphosphate (PIP3) dynamics. Inhibition of PKA activity dramatically altered membrane dynamics and attenuated formation of peripheral membrane ruffles in response to PDGF. PKA inhibition also significantly decreased the number and size of PIP3-rich membrane ruffles in response to uniform stimulation and to gradients of PDGF. This ruffling defect was quantified using a newly developed method, based on computer vision edge-detection algorithms. PKA inhibition caused a marked attenuation in the bulk accumulation of PIP3 following PDGF stimulation, without effects on PI3-kinase (PI3K) activity. The deficits in PIP3 dynamics correlated with a significant inhibition of growth factor-induced membrane recruitment of endogenous Akt and Rac activation in PKA-inhibited cells. Simultaneous inhibition of PKA and Rac had an additive inhibitory effect on growth factor-induced ruffling dynamics. Conversely, the expression of a constitutively active Rac allele was able to rescue the defect in membrane ruffling and restore the localization of a fluorescent PIP3 marker to membrane ruffles in PKA-inhibited cells, even in the absence of PI3K activity. These data demonstrate that, like Rac, PKA contributes to PIP3 and membrane dynamics independently of direct regulation of PI3K activity and suggest that modulation of PIP3/3-phosphatidylinositol (3-PI) lipids represents a major target for PKA in the regulation of PDGF-induced chemotactic events. PMID:18936099

  20. IL-17A Contributes to the Pathogenesis of Endometriosis by Triggering Proinflammatory Cytokines and Angiogenic Growth Factors.

    Science.gov (United States)

    Ahn, Soo Hyun; Edwards, Andrew K; Singh, Sukhbir S; Young, Steven L; Lessey, Bruce A; Tayade, Chandrakant

    2015-09-15

    Endometriosis is a chronic, inflammatory disease characterized by the growth of endometrial tissue in aberrant locations outside the uterus. Neoangiogenesis or establishment of new blood supply is one of the fundamental requirements of endometriotic lesion survival in the peritoneal cavity. IL-17A is emerging as a potent angiogenic and proinflammatory cytokine involved in the pathophysiology of several chronic inflammatory diseases such as rheumatoid arthritis and psoriasis. However, sparse information is available in the context of endometriosis. In this study, we demonstrate the potential importance of IL-17A in the pathogenesis and pathophysiology of endometriosis. The data show a differential expression of IL-17A in human ectopic endometriotic lesions and matched eutopic endometrium from women with endometriosis. Importantly, surgical removal of lesions resulted in significantly reduced plasma IL-17A concentrations. Immunohistochemistry revealed localization of IL-17A primarily in the stroma of matched ectopic and eutopic tissue samples. In vitro stimulation of endometrial epithelial carcinoma cells, Ishikawa cells, and HUVECs with IL-17A revealed significant increase in angiogenic (vascular endothelial growth factor and IL-8), proinflammatory (IL-6 and IL-1β), and chemotactic cytokines (G-CSF, CXCL12, CXCL1, and CX3CL1). Furthermore, IL-17A promoted tubulogenesis of HUVECs plated on Matrigel in a dose-dependent manner. Thus, we provide the first evidence, to our knowledge, that endometriotic lesions produce IL-17A and that the removal of the lesion via laparoscopic surgery leads to the significant reduction in the systemic levels of IL-17A. Taken together, our data show a likely important role of IL-17A in promoting angiogenesis and proinflammatory environment in the peritoneal cavity for the establishment and maintenance of endometriosis lesions.

  1. Computational model of vascular endothelial growth factor spatial distribution in muscle and pro-angiogenic cell therapy.

    Directory of Open Access Journals (Sweden)

    Feilim Mac Gabhann

    2006-09-01

    Full Text Available Members of the vascular endothelial growth factor (VEGF family of proteins are critical regulators of angiogenesis. VEGF concentration gradients are important for activation and chemotactic guidance of capillary sprouting, but measurement of these gradients in vivo is not currently possible. We have constructed a biophysically and molecularly detailed computational model to study microenvironmental transport of two isoforms of VEGF in rat extensor digitorum longus skeletal muscle under in vivo conditions. Using parameters based on experimental measurements, the model includes: VEGF secretion from muscle fibers; binding to the extracellular matrix; binding to and activation of endothelial cell surface VEGF receptors; and internalization. For 2-D cross sections of tissue, we analyzed predicted VEGF distributions, gradients, and receptor binding. Significant VEGF gradients (up to 12% change in VEGF concentration over 10 mum were predicted in resting skeletal muscle with uniform VEGF secretion, due to non-uniform capillary distribution. These relative VEGF gradients were not sensitive to extracellular matrix composition, or to the overall VEGF expression level, but were dependent on VEGF receptor density and affinity, and internalization rate parameters. VEGF upregulation in a subset of fibers increased VEGF gradients, simulating transplantation of pro-angiogenic myoblasts, a possible therapy for ischemic diseases. The number and relative position of overexpressing fibers determined the VEGF gradients and distribution of VEGF receptor activation. With total VEGF expression level in the tissue unchanged, concentrating overexpression into a small number of adjacent fibers can increase the number of capillaries activated. The VEGF concentration gradients predicted for resting muscle (average 3% VEGF/10 mum is sufficient for cellular sensing; the tip cell of a vessel sprout is approximately 50 mum long. The VEGF gradients also result in heterogeneity in

  2. Effect of propofol pretreatment on hippocampal monocyte chemotactic protein-1 and CC-chemokine receptor type 2 expression following forebrain ischemia-reperfusion in rats%异丙酚预先给药对大鼠前脑缺血再灌注时海马单核细胞趋化因子1及其受体表达的影响

    Institute of Scientific and Technical Information of China (English)

    郭永清; 侯晓来; 刘友章; 张华萍; 郭政

    2011-01-01

    Objective To investigate the effect of propofol pretreatment on hippocampal monocyte chemotactic protein-1 ( MCP-1 ) and CC-chemokine receptor type 2 (CCR2) expression following forebrain ischemiarepcrfusion (I/R) in rats. Methods Twenty-four male SD rats weighing 250-300 g were randomly divided into 3 groups ( n = 8 each): group Ⅰ control; group Ⅱ I/R and group Ⅲ propofol pretreatment. Cerebral I/R was induced by clamping bilateral common carotid arteries for 10 min combined with hypotension ( MAP was maintained at 35-45 mm Hg) induced by exsanguinations in group Ⅱ and Ⅲ. In group Ⅲ propofol 50 mg/kg was injected into femoral vein immediately before cerebral ischemia. The animals were sacrificed at 6 h of reperfusion. Hippocampal tissue was obtained for detection of MCP-1 mRNA and CCR2 mRNA and their protein expression by RT-PCR and Western blot technique. Results I/R significantly increased the expression of MCP-1 and CCR2 in hippoeampal tissue as compared with control group. Propofol pretreatment significantly attenuated cerebral I/R induced increase in MCP-1 and CCR2 expression. Conclusion Propofol pretreatment can significantly inhibit forebrain I/R-induced hippocampal MCP-1 and CCP2 expression.%目的 探讨异丙酚预先给药对大鼠前脑缺血再灌注时海马单核细胞趋化因子1(MCP1)及其受体(CCR2)表达的影响.方法 健康成年雄性SD大鼠24只,体重250~300g,随机分为3组(n=8):假手术组(S组)仅暴露双侧颈总动脉及股动静脉置管,不夹闭;缺血再灌注组(IR组)采用夹闭双侧颈总动脉10 min合并放血降压再回输法制备前脑缺血再灌注损伤模型;异丙酚预先给药组(P组)脑缺血前即刻股静脉注射异丙酚50 mg/kg.于再灌注6 h时处死大鼠取脑,分离海马神经元,采用RT-PCR法测定MCP-1 mRNA和CCR2mRNA的表达,Western blot法测定MCP-1和CCR2蛋白的表达.结果 IR组和P组海马神经元MCP-1及CCR2表达较S组上调(P<0.05);P组海马神经元MCP-1

  3. 西洛他唑联合替米沙坦对早期2型糖尿病肾病血清单核细胞趋化蛋白1和可溶性细胞间黏附分子1的影响%The Effect of Cilostazol Combined with Telmisartan on Serum Monocyte Chemotactic Protein-1 and Soluble Intercellu-lar Adhesion Molecule-1 in Early Type 2 Diabetic Nephropathy

    Institute of Scientific and Technical Information of China (English)

    焦秀敏; 武晋晓; 陈彬; 袁涛; 吕肖锋

    2014-01-01

    Objective To observe the effect of cilostazol combined with telmisartan on serum monocyte chemotactic pro-tein-1 (MCP-1) and soluble intercellular adhesion molecule-1 (sICAM-1) in early type 2 diabetic nephropathy. Methods A total of 60 patients with early type 2 diabetic nephropathy were randomly divided into two groups:thirty patients in group A were treated with cilostazol and telmisartan based on routine treatment, while thirty patients in group B were treated with telmisartan a-lone. The levels of 24-h urinary albumin, blood pressure, MCP-1, sICAM-1, alanine aminotransferase, creatinine and glycosy-lated hemoglobin in two groups were compared before treatment and 4 weeks after treatment. Results The levels of 24-h urinary albumin, MCP-1 and sICAM-1 were significantly decreased in both groups after treatment for four weeks, and the differences were significant (P<0. 05). After treatment, the levels of 24-h urinary albumin, MCP-1 and sICAM-1 in group A were obvious-ly lower than those in group B (P<0. 05). Conclusion Cilostazol combined with telmisartan can significantly decrease the uri-nary albumin level in the patients with early type 2 diabetes nephropathy, it can protect the kidney, and delay the progression of early diabetic nephropathy. It is relatively safe in clinical application.%目的:观察西洛他唑联合替米沙坦对早期2型糖尿病肾病( diabetic nephropathy, DN)血清单核细胞趋化蛋白1(MCP-1)和可溶性细胞间黏附分子1(sICAM-1)的影响。方法将我院收治的早期2型DN 60例随机分为西洛他唑联合替米沙坦组和替米沙坦组两组各30例,在常规治疗基础上西洛他唑联合替米沙坦组予西洛他唑和替米沙坦治疗,替米沙坦组仅予替米沙坦治疗,观察比较两组治疗前及治疗4周后24 h尿微量白蛋白、血压及血清MCP-1、sIcAM-1、丙氨酸转氨酶、肌酐、糖化血红蛋白水平。结果治疗4周后,两组24 h尿微量白蛋白及血清MCP-1、sIcAM-1均较

  4. Serum leptin levels in relation to circulating cytokines, chemokines, adhesion molecules and angiogenic factors in normal pregnancy and preeclampsia

    Directory of Open Access Journals (Sweden)

    Karádi István

    2011-09-01

    Full Text Available Abstract Objective In this study, we determined circulating levels of C-reactive protein, several cytokines, chemokines, adhesion molecules and angiogenic factors along with those of leptin in healthy non-pregnant and pregnant women and preeclamptic patients, and investigated whether serum leptin levels were related to the clinical characteristics and measured laboratory parameters of the study participants. Methods Sixty preeclamptic patients, 60 healthy pregnant women and 59 healthy non-pregnant women were involved in this case-control study. Levels of leptin and transforming growth factor (TGF-beta1 in maternal sera were assessed by ELISA. Serum levels of interleukin (IL-1beta, IL-1 receptor antagonist (IL-1ra, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p40, IL-12p70, IL-18, interferon (IFN-gamma, tumor necrosis factor (TNF-alpha, interferon-gamma-inducible protein (IP-10, monocyte chemotactic protein (MCP-1, intercellular adhesion molecule (ICAM-1 and vascular cell adhesion molecule (VCAM-1 were determined by multiplex suspension array. Serum C-reactive protein (CRP concentrations were measured by an autoanalyzer. Serum total soluble fms-like tyrosine kinase-1 (sFlt-1 and biologically active placental growth factor (PlGF levels were determined by electrochemiluminescence immunoassay. For statistical analyses, non-parametric methods were applied. Results There were significant differences in most of the measured laboratory parameters among the three study groups except for serum IL-1beta and TGF-beta1 levels. Serum leptin levels were significantly higher in preeclamptic patients and healthy pregnant women than in healthy non-pregnant women. Additionally, preeclamptic patients had significantly higher leptin levels as compared to healthy pregnant women. Serum leptin levels were independently associated with BMI in healthy non-pregnant women. In healthy pregnant women, both BMI and serum CRP concentrations showed significant positive linear

  5. Regarding proton form factors

    OpenAIRE

    Bloch, J. C. R.; Krassnigg, A.; Roberts, C. D.

    2003-01-01

    The proton's elastic electromagnetic form factors are calculated using an Ansatz for the nucleon's Poincare' covariant Faddeev amplitude that only retains scalar diquark correlations. A spectator approximation is employed for the current. On the domain of q^2 accessible in modern precision experiments these form factors are a sensitive probe of nonperturbative strong interaction dynamics. The ratio of Pauli and Dirac form factors can provide realistic constraints on models of the nucleon and ...

  6. Bayesian Group Factor Analysis

    OpenAIRE

    Virtanen, Seppo; Klami, Arto; Khan, Suleiman A; Kaski, Samuel

    2011-01-01

    We introduce a factor analysis model that summarizes the dependencies between observed variable groups, instead of dependencies between individual variables as standard factor analysis does. A group may correspond to one view of the same set of objects, one of many data sets tied by co-occurrence, or a set of alternative variables collected from statistics tables to measure one property of interest. We show that by assuming group-wise sparse factors, active in a subset of the sets, the variat...

  7. Group Factor Analysis

    OpenAIRE

    Klami, Arto; Virtanen, Seppo; Leppäaho, Eemeli; Kaski, Samuel

    2014-01-01

    Factor analysis provides linear factors that describe relationships between individual variables of a data set. We extend this classical formulation into linear factors that describe relationships between groups of variables, where each group represents either a set of related variables or a data set. The model also naturally extends canonical correlation analysis to more than two sets, in a way that is more flexible than previous extensions. Our solution is formulated as variational inferenc...

  8. Analytic Couple Modeling Introducing Device Design Factor, Fin Factor, Thermal Diffusivity Factor, and Inductance Factor

    Science.gov (United States)

    Mackey, Jon; Sehirlioglu, Alp; Dynys, Fred

    2014-01-01

    A set of convenient thermoelectric device solutions have been derived in order to capture a number of factors which are previously only resolved with numerical techniques. The concise conversion efficiency equations derived from governing equations provide intuitive and straight-forward design guidelines. These guidelines allow for better device design without requiring detailed numerical modeling. The analytical modeling accounts for factors such as i) variable temperature boundary conditions, ii) lateral heat transfer, iii) temperature variable material properties, and iv) transient operation. New dimensionless parameters, similar to the figure of merit, are introduced including the device design factor, fin factor, thermal diffusivity factor, and inductance factor. These new device factors allow for the straight-forward description of phenomenon generally only captured with numerical work otherwise. As an example a device design factor of 0.38, which accounts for thermal resistance of the hot and cold shoes, can be used to calculate a conversion efficiency of 2.28 while the ideal conversion efficiency based on figure of merit alone would be 6.15. Likewise an ideal couple with efficiency of 6.15 will be reduced to 5.33 when lateral heat is accounted for with a fin factor of 1.0.

  9. INTEGER FACTORIZATION IMPLEMENTATIONS

    Directory of Open Access Journals (Sweden)

    Reza Alimoradi

    2016-06-01

    Full Text Available One difficult problem of mathematics that forms the basics of some public key cryptography systems like RSA, is finding factors of big numbers. To solve this problem, many factorization algorithms have been offered with different complexities. Many attempts have been made today to implement these factorization algorithms. And these implementations are different from various aspects. Each of these factorization algorithms is efficient for numbers with a specific size. These algorithms can be compared with regard to time and memory complexity. In this paper, some of these implementations are studied and compared and consequently the most appropriate one will be introduced.

  10. Porphyromonas gingivalis-induced production of reactive oxygen species, tumor necrosis factor-α, interleukin-6, CXCL8 and CCL2 by neutrophils from localized aggressive periodontitis and healthy donors

    DEFF Research Database (Denmark)

    Damgaard, C; Kantarci, A; Holmstrup, P;

    2016-01-01

    healthy controls release the proinflammatory cytokines interleukin (IL)-6, tumor necrosis factor α (TNF-α), the chemokine (C-X-C motif) ligand 8 (CXCL8; also known as IL-8) and chemokine (C-C motif) ligand 2 (CCL2; also known as monocyte chemotactic protein-1) and intracellular reactive oxygen species...... of neutrophils were investigated. RESULTS: Upon stimulation with P. gingivalis, neutrophils from subjects with LAgP and healthy controls released similar quantities of IL-6, TNF-α, CXCL8, CCL2 and intracellular ROS. The presence of RBCs amplified the release of IL-6, TNF-α and CCL2 statistically significant...... in both groups, but reduced the generation of ROS in the group of healthy controls, and showed a similar tendency in the group of subjects with LAgP. RvE1 had no impact on the production of intracellular ROS, TNF-α, IL-6, CXCL8 and CCL2 by neutrophils from either group, but tended to reduce the generation...

  11. Induction of Monocyte Chemoattractant Proteins in Macrophages via the Production of Granulocyte-macrophage Colony Stimulating Factor by Breast Cancer Cells

    Directory of Open Access Journals (Sweden)

    Teizo eYoshimura

    2016-01-01

    Full Text Available Monocyte chemoattractant protein-1 (MCP-1/CCL2 plays an important role in the initiation and progression of cancer. We previously reported that in 4T1 murine breast cancer, non-tumor stromal cells, including macrophages, were the major source of MCP-1. In the present study, we analyzed the potential mechanisms by which MCP-1 is upregulated in macrophages infiltrating 4T1 tumors. We found that cell-free culture supernatants of 4T1 cells (4T1-sup markedly upregulated MCP-1 production by peritoneal inflammatory macrophages. 4T1-sup also upregulated other MCPs, such as MCP-3/CCL7 and MCP-5/CCL12, but modestly neutrophil chemotactic chemokines, such as KC/CXCL1 or MIP-2/CXCL2. Physicochemical analysis indicated that an approximately 2 to 3 kDa 4T1 cell product was responsible for the capacity of 4T1-sup to upregulate MCP-1 expression by macrophages. A neutralizing antibody against granulocyte-macrophage-colony stimulating factor (GM-CSF, but not macrophage-colony stimulating factor, almost completely abrogated MCP-1-inducing activity of 4T1-sup, and recombinant GM-CSF potently up-regulated MCP-1 production by macrophages. The expression levels of GM-CSF in 4T1 tumors in vivo were higher than other tumors, such as Lewis lung carcinoma. Treatment of mice with anti-GM-CSF antibody significantly reduced the growth of 4T1 tumors at the injection sites but did not reduce MCP-1 production or lung metastasis in tumor-bearing mice. These results indicate that 4T1 cells have the capacity to directly up-regulate MCP-1 production by macrophages by releasing GM-CSF; however, other mechanisms are also involved in increased MCP-1 levels in the 4T1 tumor microenvironment.

  12. Human factor in extremes

    NARCIS (Netherlands)

    McFedries, R.

    2013-01-01

    The maritime industry often has the focus on the developments and innovations regarding the build of vessels, the electrical adjustments, financing and regulatory factors. What about the people who work on board vessels? What kind of factors do they encounter and what kind of effect does this have o

  13. Approximate and Incomplete Factorizations

    NARCIS (Netherlands)

    Chan, T.F.; Vorst, H.A. van der

    2001-01-01

    In this chapter, we give a brief overview of a particular class of preconditioners known as incomplete factorizations. They can be thought of as approximating the exact LU factorization of a given matrix A (e.g. computed via Gaussian elimination) by disallowing certain ll-ins. As opposed to other PD

  14. Pancreatic Cancer Risk Factors

    Science.gov (United States)

    ... factors can affect a person’s chance of getting cancer of the pancreas. Most of these are risk factors for exocrine ... Chronic pancreatitis, a long-term inflammation of the pancreas, is linked with an increased risk of pancreatic cancer (especially in smokers), but most people with pancreatitis ...

  15. Baryon form factors

    CERN Document Server

    Kubis, B; Meißner, Ulf G; Mei{\\ss}ner, Ulf-G.

    1999-01-01

    We calculate the form factors of the baryon octet in the framework of heavy baryon chiral perturbation theory. The calculated charge radius of the show that kaon loop effects can play a significant role in the neutron electric form factor. Furthermore. we derive generalized Caldi-Pagels relations between various charge radii which are free of chiral loop effects.

  16. The Transcription Factor Encyclopedia

    DEFF Research Database (Denmark)

    Yusuf, Dimas; Butland, Stefanie L; Swanson, Magdalena I;

    2012-01-01

    ABSTRACT: Here we present the Transcription Factor Encyclopedia (TFe), a new web-based compendium of mini review articles on transcription factors (TFs) that is founded on the principles of open access and collaboration. Our consortium of over 100 researchers has collectively contributed over 130...

  17. Factors of schizoid personality.

    Science.gov (United States)

    Raine, A; Allbutt, J

    1989-02-01

    The increasing use of schizoid personality scales with normals has led to a number of validation studies, but to date there are no published analyses of the factorial structure of these scales. This study presents results of factor analyses of schizoid personality scales in an initial attempt to delineate their factorial structure. Questionnaires were administered to 114 male and female undergraduates and factor analysed using Varimax, Quartimax, and Oblique rotations. A two-factor varimax solution yielded a first factor accounting for 49 per cent of total unrotated variance with high (0.70 to 0.91) loadings from Hallucinatory predisposition, Perceptual aberration, Schizophrenism, STA and STB scales, and was interpreted as reflecting a general factor of schizoid personality disorder. Psychoticism and Social anhedonia loaded on a second factor accounting for 20 per cent of the variance which was uncorrelated (r = 0.09) with factor 1. This factor solution was closely replicated using quartimax and oblimin rotation criteria. It is concluded that Social anhedonia and Psychoticism represent a separate dimension from other scales which reflect the more positive features of schizoid personality.

  18. Growth factors in haemopoiesis.

    Science.gov (United States)

    Jones, A L; Millar, J L

    1989-01-01

    Haemopoietic growth factors have for over two decades allowed experimentalists to grow haemopoietic bone marrow cells in vitro. With refinements in technique and the discovery of novel growth factors, all of the known haemopoietic lineages can now be grown in vitro. This has allowed a much greater understanding of the complex process of haemopoiesis from the haemopoietic stem cell to the mature, functioning end-cell. The in vivo action of these growth factors has been harder to investigate. Although recombinant technology has afforded us the much greater quantities necessary for in vivo work, problems remain with administration because of effects on other tissues. Interpretation of results is difficult because of the complex inter-relationships which exist between factors. Some of these have been defined in vitro and it appears likely that they also operate in vivo. Erythropoietin is a physiological regulator of erythropoiesis. It has been detected in vivo with levels responding appropriately to stress (i.e. elevated in anaemia) and, when administered in pharmacological doses, has been shown to correct anaemia. Granulocyte/macrophage colony-stimulating factor (GM-CSF) has been detected in vivo and may influence the production and function of granulocytes and macrophages, although how it is regulated is unknown. Granulocyte colony-stimulating factor (G-CSF) and macrophage colony-stimulating factor are ore lineage-specific. Interleukin 3 (IL-3), although it has not been detected in vivo, may act on a primitive marrow precursor by expanding the population and making these cells more susceptible to other growth factors, such as GM-CSF. Interleukin 1 (IL-1) has been detected in vivo, does not appear to have any isolated action on bone marrow (except possibly radioprotection) but probably acts synergistically with other growth factors, such as G-CSF. Interleukins 2, 4, 5 and 6 have not been detected in vivo. All have effects on B-cells. In addition IL-2 is an essential

  19. Growth factor signalling.

    Science.gov (United States)

    de Laat, S W; Boonstra, J; Defize, L H; Kruijer, W; van der Saag, P T; Tertoolen, L G; van Zoelen, E J; den Hertog, J

    1999-01-01

    Signalling between cells in the developing vertebrate embryo is essential for normal embryonic development. In the mid 1970's, signal transduction research started at the Hubrecht Laboratory with special emphasis on analysis of the signalling mechanisms that direct cell proliferation and differentiation. The introduction of in vitro model systems contributed tremendously to the success of the signal transduction research at the Hubrecht Laboratory. Initially neuroblastoma cell lines, and later embryonal carcinoma and embryonal stem cells played an important role in identification of the molecular key players in developmental signalling. For instance, embryonal carcinoma cells were used to identify and characterise polypeptide growth factors. Growth factor signalling research was extended to analysis of growth factor receptor activation. Moreover, the second messenger systems that are linked to growth factor receptors were studied, as well as the nuclear responses to growth factor receptor activation. Finally, the role of growth factor signalling in differentiation was established using embryonal carcinoma cells. Here, we will review work that was characteristic for the growth factor receptor signalling research that was done at the Hubrecht Laboratory between 1980 and the early 1990's.

  20. Conundrums with uncertainty factors.

    Science.gov (United States)

    Cooke, Roger

    2010-03-01

    The practice of uncertainty factors as applied to noncancer endpoints in the IRIS database harkens back to traditional safety factors. In the era before risk quantification, these were used to build in a "margin of safety." As risk quantification takes hold, the safety factor methods yield to quantitative risk calculations to guarantee safety. Many authors believe that uncertainty factors can be given a probabilistic interpretation as ratios of response rates, and that the reference values computed according to the IRIS methodology can thus be converted to random variables whose distributions can be computed with Monte Carlo methods, based on the distributions of the uncertainty factors. Recent proposals from the National Research Council echo this view. Based on probabilistic arguments, several authors claim that the current practice of uncertainty factors is overprotective. When interpreted probabilistically, uncertainty factors entail very strong assumptions on the underlying response rates. For example, the factor for extrapolating from animal to human is the same whether the dosage is chronic or subchronic. Together with independence assumptions, these assumptions entail that the covariance matrix of the logged response rates is singular. In other words, the accumulated assumptions entail a log-linear dependence between the response rates. This in turn means that any uncertainty analysis based on these assumptions is ill-conditioned; it effectively computes uncertainty conditional on a set of zero probability. The practice of uncertainty factors is due for a thorough review. Two directions are briefly sketched, one based on standard regression models, and one based on nonparametric continuous Bayesian belief nets. PMID:20030767

  1. Two-factor authentication

    CERN Document Server

    Stanislav, Mark

    2015-01-01

    During the book, readers will learn about the various technical methods by which two-factor authentication is implemented, security concerns with each type of implementation, and contextual details to frame why and when these technologies should be used. Readers will also be provided with insight about the reasons that two-factor authentication is a critical security control, events in history that have been important to prove why organization and individual would want to use two factor, and core milestones in the progress of growing the market.

  2. Fano factor in xenon

    International Nuclear Information System (INIS)

    The Fano factor and W value in xenon have been measured with a gridded ionization chamber for 5.3-MeV α particles. We obtained a value for the Fano factor of 0.29±0.02 and the W value of 21.9±0.3 eV. This W value is nearly equal to those for α and β particles measured by Jesse and Sadauskis [Phys. Rev. 90, 1120 (1953); 97, 1668 (1955)]. The Fano factor is considerably larger than the value reported for x rays using a proportional scintillation counter. The reason for this difference is discussed

  3. Increased expression of granulocyte colony-stimulating factor mediates mesenchymal stem cells recruitment after vascular injury

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yong; LIU Ying-xi; XIEShuang-lun; DENG Bing-qing; WANG Jing-feng; NIE Ru-qiong

    2011-01-01

    Background Recent studies indicate that bone marrow-derived cells may significantly contribute to atherosclerosis,post-angioplasty restenosis and transplantation-associated vasculopathy.The responsible bone marrow (BM) cells and mechanisms regulating the mobilization of these cells are currently unclear.The purpose of this study was to investigate the expression of granulocyte colony-stimulating factor (G-CSF) on injured arteries and its effects on mesenchymal stem cells (MSCs) differentiation into vascular smooth muscle cells (VSMCs) in the process of vascular remodeling.Methods Balloon-mediated vascular injury was established in female rats (n=1O0) which received radioprotective whole female BM cells by tail vein injection and male MSCs through a tibial BM injection after lethal irradiation.The injured and contralateral carotid arteries were harvested at 3,7,14 and 28 days after treatment.Results Morphometric analysis indicated that intima to media area-ratio (I/M ratio) significantly increased at 28 days,0.899±-0.057 (P <0.01),compared with uninjured arteries.Combining fluorescence in situ hybridization (FISH) and immunohistochemical analysis showed that a significant number of the neointimal cells derived from MSCs,(45.2±8.5)% at 28 days (P=0.01),compared with (23.5±6.3)% at 14 days.G-CSF was induced in carotid arteries subject to balloon angioplasty (fold mRNA change=8.67±0.63 at three days,relative G-CSF protein=0.657±-0.011 at three days,P <0.01,respectively,compared with uninjured arteries).G-CSF was chemotactic for MSCs but did not affect the differentiation of MSCs into smooth-muscle-like cells.Conclusion Increased expression of G-CSF by injured arteries plays an essential role in contribution to recruitment and homing of MSCs to the site of the arterial lesion.

  4. Nucleon Form Factors

    Energy Technology Data Exchange (ETDEWEB)

    Cornelis de Jager

    2004-09-01

    The experimental and theoretical status of elastic electron scattering from the nucleon is reviewed. As a consequence of new experimental facilities, data of unprecedented precision have recently become available for the electromagnetic and the strange form factors of the nucleon.

  5. Risk factors for neoplasms

    International Nuclear Information System (INIS)

    A broad survey is given of risk factors for neoplasms. The main carcinogenic substances (including also ionizing radiation and air pollution) are listed, and are correlated with the risk factors for various cancers most frequently explained and discussed in the literature. The study is intended to serve as a basis for a general assessment of the incidence of neoplasms in children, and of cancer mortality in the entire population of Bavaria in the years 1983-1989, or 1979-1988, respectively, with the principal idea of drawing up an environment-related health survey. The study therefore takes into account not only ionizing radiation as a main risk factor, but also other risk factors detectable within the ecologic context, as e.g. industrial installations and their effects, refuse incineration plants or waste dumps, or the social status. (orig./MG)

  6. Factor X assay

    Science.gov (United States)

    ... D, Neff AT. Rare coagulation factor deficiencies. In: Hoffman R, Benz EJ Jr, Silberstein LE, Heslop HE, ... Laboratory evaluation of hemostatic and thrombotic disorders. In: Hoffman R, Benz EJ Jr, Silberstein LE, Heslop HE, ...

  7. Factor XII assay

    Science.gov (United States)

    ... D, Neff AT. Rare coagulation factor deficiencies. In: Hoffman R, Benz EJ Jr, Silberstein LE, Heslop HE, ... Laboratory evaluation of hemostatic and thrombotic disorders. In: Hoffman R, Benz EJ Jr, Silberstein LE, Heslop HE, ...

  8. Brain derived neurotrophic factor

    DEFF Research Database (Denmark)

    Mitchelmore, Cathy; Gede, Lene

    2014-01-01

    Brain Derived Neurotrophic Factor (BDNF) is a neurotrophin with important functions in neuronal development and neuroplasticity. Accumulating evidence suggests that alterations in BDNF expression levels underlie a variety of psychiatric and neurological disorders. Indeed, BDNF therapies are...

  9. FGF growth factor analogs

    Energy Technology Data Exchange (ETDEWEB)

    Zamora, Paul O. (Gaithersburg, MD); Pena, Louis A. (Poquott, NY); Lin, Xinhua (Plainview, NY); Takahashi, Kazuyuki (Germantown, MD)

    2012-07-24

    The present invention provides a fibroblast growth factor heparin-binding analog of the formula: ##STR00001## where R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, X, Y and Z are as defined, pharmaceutical compositions, coating compositions and medical devices including the fibroblast growth factor heparin-binding analog of the foregoing formula, and methods and uses thereof.

  10. Factors Affecting Wound Healing

    OpenAIRE

    Guo, S; DiPietro, L. A.

    2010-01-01

    Wound healing, as a normal biological process in the human body, is achieved through four precisely and highly programmed phases: hemostasis, inflammation, proliferation, and remodeling. For a wound to heal successfully, all four phases must occur in the proper sequence and time frame. Many factors can interfere with one or more phases of this process, thus causing improper or impaired wound healing. This article reviews the recent literature on the most significant factors that affect cutane...

  11. Brain derived neurotrophic factor

    DEFF Research Database (Denmark)

    Mitchelmore, Cathy; Gede, Lene

    2014-01-01

    Brain Derived Neurotrophic Factor (BDNF) is a neurotrophin with important functions in neuronal development and neuroplasticity. Accumulating evidence suggests that alterations in BDNF expression levels underlie a variety of psychiatric and neurological disorders. Indeed, BDNF therapies are curre......Brain Derived Neurotrophic Factor (BDNF) is a neurotrophin with important functions in neuronal development and neuroplasticity. Accumulating evidence suggests that alterations in BDNF expression levels underlie a variety of psychiatric and neurological disorders. Indeed, BDNF therapies...

  12. Electromagetic proton form factors

    OpenAIRE

    Hussein, M Y

    2006-01-01

    The electromagnetic form factors are crucial to our understanding of the proton internal structure, and thus provide a strong constraint of the distributions of the charge and magnetization current within the proton. We adopted the quark-parton model for calculating and understanding the charge structure of the proton interms of the electromagnetic form factors. A remarkable agreement with the available experimental evidence is found.

  13. Factors influencing donor return.

    OpenAIRE

    Schlumpf, KS; Glynn, SA; Schreiber, GB; Wright, DJ; Randolph Steele, W; Tu, Y.; Hermansen, S; Higgins, MJ; Garratty, G; Murphy, EL

    2007-01-01

    BACKGROUND: To predict future blood donation behavior and improve donor retention, it is important to understand the determinants of donor return. STUDY DESIGN AND METHODS: A self-administered questionnaire was completed in 2003 by 7905 current donors. With data mining methods, all factors measured by the survey were ranked as possible predictors of actual return within 12 months. Significant factors were analyzed with logistic regression to determine predictors of intention and of actual ret...

  14. The stem factor challenge

    International Nuclear Information System (INIS)

    One of the most important challenges that still needs to be met in the effort to understand the operation of motor-operated, rising-stem valves is the ability to determine stem factor throughout the valve's load range. The stem factor represents the conversion of operator torque to stem thrust. Determining the stem factor is important because some motor-operated valves (MOVs) cannot be tested in the plant at design basis conditions. The ability of these valves to perform their design basis function (typically, to operate against specified flow and pressure loads) must be ensured by analytical methods or by extrapolating from the results of tests conducted at lower loads. Because the stem factor tends to vary in response to friction and lubrication phenomena that occur during loading and wedging, analytical methods and extrapolation methods have been difficult to develop and implement. Early investigations into variability in the stem factor tended to look only at the tip of the iceberg; they focused on what was happening at torque switch trip, which usually occurs at full wedging. In most stems, the stem factor is better (lower) in the wedging transient than before wedging, so working with torque switch trip data alone led many early researchers to false conclusions about the relationship between stem factor and load. However, research at the Idaho National Engineering Laboratory (INEL) has taken a closer look at what happens during the running portion of the closing stroke along with the wedging portion. This shift in focus is important, because functional failure of a valve typically consists of a failure to isolate flow, not a failure to achieve full wedging. Thus, the stem factor that must be determined for a valve's design basis closing requirements is the one that corresponds with the running load before wedging

  15. Sparse Multivariate Factor Regression

    OpenAIRE

    Kharratzadeh, Milad; Coates, Mark

    2015-01-01

    We consider the problem of multivariate regression in a setting where the relevant predictors could be shared among different responses. We propose an algorithm which decomposes the coefficient matrix into the product of a long matrix and a wide matrix, with an elastic net penalty on the former and an $\\ell_1$ penalty on the latter. The first matrix linearly transforms the predictors to a set of latent factors, and the second one regresses the responses on these factors. Our algorithm simulta...

  16. Factorizations and Physical Representations

    OpenAIRE

    Revzen, M.; F. C. Khanna(Edmonton, Canada); Mann, A.; Zak, J.

    2005-01-01

    A Hilbert space in M dimensions is shown explicitly to accommodate representations that reflect the prime numbers decomposition of M. Representations that exhibit the factorization of M into two relatively prime numbers: the kq representation (J. Zak, Phys. Today, {\\bf 23} (2), 51 (1970)), and related representations termed $q_{1}q_{2}$ representations (together with their conjugates) are analysed, as well as a representation that exhibits the complete factorization of M. In this latter repre...

  17. Physics of Factorization

    OpenAIRE

    Revzen, M.; Mann, A.; Zak, J.

    2005-01-01

    The N distinct prime numbers that make up a composite number M allow $2^{N-1}$ bi partioning into two relatively prime factors. Each such pair defines a pair of conjugate representations. These pairs of conjugate representations, each of which spans the M dimensional space are the familiar complete sets of Zak transforms (J. Zak, Phys. Rev. Let.{\\bf 19}, 1385 (1967)) which are the most natural representations for periodic systems. Here we show their relevance to factorizations. An example is ...

  18. Interest rates factor model

    Science.gov (United States)

    Lee, Sangwook; Kim, Min Jae; Kim, Soo Yong

    2011-07-01

    Interdependence of the interest rates of the US, the UK, and Japan is analyzed in this work by means of spectral analysis and network methods. A predominant effective factor in the interest rate market is which country floats a bond issue, and a minor effective factor is time to maturity of bonds. Power-law cross-correlation among different countries is analyzed by the detrended cross-correlation analysis method. Long-range cross-correlation is found between the first factors of interest rate, while there is no cross-correlation between some of the second factors. The tail dependency is indicated by tail indices from Archimedean copulas, including an empirical copula. In contrast to other pairs, the US-UK first factor pair has tail dependencies in both the upper-tail and lower-tail. Dynamic properties of interest rate are modeled by a stochastic volatility model. The properties of mean reverting and volatility clustering are observed and reflected in this model. The proposed simulation method combines the dependence structures and the factor dynamics model; it simultaneously describes the interest rates of different countries.

  19. Factorization and pion form factor in QCD

    International Nuclear Information System (INIS)

    The behaviour of the pion electromagnetic form factor (EMFF) in the framework of quantum chromodynamics (QCD) is discussed. Pion is considered to be a quark-antiquark bound state. It is proposed to use an OPE description of the bound state structure by matrix elements of certain local gauge-invariant operators. Short-distance quark interactions is proved using a direct analysis of perturbation theory in the α-parametric representation of the Feynman diagrams. It is shown that the short-distance parton picture privides a self-consistent description of the large Q2 momentum behaviour of the pion EMFF in QCD. Pion EMFF asymptotics is expressed in terms of fu fundamental constants of the theory

  20. CPG寡核苷酸对卵清蛋白致敏幼鼠血清中Th1/Th2细胞因子及肥大细胞趋化蛋白1的影响%Effect of CPG oligodeoxynucleotides on Th1/Th2 and mast cell chemotactic protein1 in serum with OVA induced food allergy in young mice

    Institute of Scientific and Technical Information of China (English)

    王本贞; 郑成中

    2015-01-01

    分;眼球取血,检测血清中OVA-IgE、肥大细胞趋化蛋白1(mast cell chemotactic protein 1,mMCP-1)及Th1/Th2相关细胞因子IFN-γ、IL-4的水平;空肠组织行病理学检测。结果除对照组外,致敏组小鼠均出现不同程度过敏症状,空肠表现为Ⅰ型变态反应病理特点,Th2细胞因子、OVA-IgE、mMCP-1水平升高,20μg、50μg致敏组Th1水平降低,50μg致敏组指标改变最显著;与致敏组相比,干预组小鼠过敏症状及病理改变明显减轻,Th2细胞因子、IgE及mMCP-1水平降低,Th1水平升高。结论用50μg OVA建立的BALB/c幼鼠食物过敏模型致敏效果最好,CPG-ODN通过改善Th1/Th2失衡状态,抑制幼鼠食物过敏反应。mMCP-1在过敏性疾病的发生、发展中起重要作用,有望成为食物过敏临床检测指标之一。

  1. La adolescencia: factores criticos

    Directory of Open Access Journals (Sweden)

    Noé Ardila Espinel

    1980-01-01

    Full Text Available Ten factors, tbat are considered by several psychologists as sensitive and characterístíc of the adolescent period, were tested by means of a Lykert type scale of 50 ítems, Seventy-eight subjects divided in three groups (U·13 years, early adolescence; 14·17 years, middle adolescence; 18-22 years, late adolescence answered the scale, Results índicate age differences. The factors that are in conflict duríng the middle adolescente are: emotional control, self control, social behavior, logical thinking, tendeney toward independency, economic índependency, family índependency, relígíous independency, rules conflict,and affective development, The factors change in direction before, during, and after adolescence

  2. Multi-factor authentication

    Energy Technology Data Exchange (ETDEWEB)

    Hamlet, Jason R; Pierson, Lyndon G

    2014-10-21

    Detection and deterrence of spoofing of user authentication may be achieved by including a cryptographic fingerprint unit within a hardware device for authenticating a user of the hardware device. The cryptographic fingerprint unit includes an internal physically unclonable function ("PUF") circuit disposed in or on the hardware device, which generates a PUF value. Combining logic is coupled to receive the PUF value, combines the PUF value with one or more other authentication factors to generate a multi-factor authentication value. A key generator is coupled to generate a private key and a public key based on the multi-factor authentication value while a decryptor is coupled to receive an authentication challenge posed to the hardware device and encrypted with the public key and coupled to output a response to the authentication challenge decrypted with the private key.

  3. Geothermal Plant Capacity Factors

    Energy Technology Data Exchange (ETDEWEB)

    Greg Mines; Jay Nathwani; Christopher Richard; Hillary Hanson; Rachel Wood

    2015-01-01

    The capacity factors recently provided by the Energy Information Administration (EIA) indicated this plant performance metric had declined for geothermal power plants since 2008. Though capacity factor is a term commonly used by geothermal stakeholders to express the ability of a plant to produce power, it is a term frequently misunderstood and in some instances incorrectly used. In this paper we discuss how this capacity factor is defined and utilized by the EIA, including discussion on the information that the EIA requests from operations in their 923 and 860 forms that are submitted both monthly and annually by geothermal operators. A discussion is also provided regarding the entities utilizing the information in the EIA reports, and how those entities can misinterpret the data being supplied by the operators. The intent of the paper is to inform the facility operators as the importance of the accuracy of the data that they provide, and the implications of not providing the correct information.

  4. Human factors guides

    International Nuclear Information System (INIS)

    This document presents human factors guides, which have been developed in order to provide licensees of the AECB with advice as to how to address human factors issues within the design and assessment process. This documents presents the results of a three part study undertaken to develop three guides which are enclosed in this document as Parts B, C and D. As part of the study human factors standards, guidelines, handbooks and other texts were researched, to define those which would be most useful to the users of the guides and for the production of the guides themselves. Detailed specifications were then produced to outline the proposed contents and format of the three guides. (author). 100 refs., 3 tabs., 11 figs

  5. Consumption of polyphenol-rich peach and plum juice prevents risk factors for obesity-related metabolic disorders and cardiovascular disease in Zucker rats.

    Science.gov (United States)

    Noratto, Giuliana; Martino, Hercia S D; Simbo, Sunday; Byrne, David; Mertens-Talcott, Susanne U

    2015-06-01

    Polyphenols from fruits have been implied in the prevention of risk factors for cardiometabolic disorders and cardiovascular disease. The purpose of this study was to investigate if the consumption of peach and plum juice has a protective effect against obesity and metabolic disorders that promote the development of cardiovascular diseases. Obese Zucker and lean rats were fed with peach, plum juice ad libitum or placebo. Body weight gain, biochemical markers and molecular markers for inflammation and cardiovascular disease in heart tissue were quantified. Results show that peach and plum juice consumption protected against a combination of obesity-induced metabolic disorders including hyperglycemia, insulin and leptin resistance, dyslipidemia and low-density lipoprotein oxidation. This was accompanied by a decreased expression of pro-atherogenic and pro-inflammatory biomarkers in plasma and heart tissues including intercellular cell adhesion molecule-1, monocyte chemotactic protein-1, NF-κB and foam cell adherence to aortic arches. In addition, peach and plum juice consumption decreased the levels of angiotensin II in plasma and its receptor Agtr1 in heart tissues, suggesting a role of peach and plum polyphenols as peroxisome proliferator-activated receptor-γ agonists. Furthermore, only plum juice significantly prevented body weight gain and increased the ratio high-density lipoprotein cholesterol/total cholesterol in plasma. This effect is most likely attributed to the plum's higher content of polyphenols (three times that of peach). Altogether, these results imply that cardioprotective effects can be achieved by replacing drinks high in sugar content with fruit juice rich in polyphenols in a diet.

  6. Activation of the human keratinocyte B1 bradykinin receptor induces expression and secretion of metalloproteases 2 and 9 by transactivation of epidermal growth factor receptor.

    Science.gov (United States)

    Matus, Carola E; Ehrenfeld, Pamela; Pavicic, Francisca; González, Carlos B; Concha, Miguel; Bhoola, Kanti D; Burgos, Rafael A; Figueroa, Carlos D

    2016-09-01

    The B1 bradykinin receptor (BDKRB1) is a component of the kinin cascade localized in the human skin. Some of the effects produced by stimulation of BDKRB1 depend on transactivation of epidermal growth factor receptor (EGFR), but the mechanisms involved in this process have not been clarified yet. The primary purpose of this study was to determine the effect of a BDKRB1 agonist on wound healing in a mouse model and the migration and secretion of metalloproteases 2 and 9 from human HaCaT keratinocytes and delineate the signalling pathways that triggered their secretion. Although stimulation of BDKRB1 induces weak chemotactic migration of keratinocytes and wound closure in an in vitro scratch-wound assay, the BDKRB1 agonist improved wound closure in a mouse model. BDKRB1 stimulation triggers synthesis and secretion of both metalloproteases, effects that depend on the activity of EGFR and subsequent phosphorylation of ERK1/2 and p38 mitogen-activated protein kinases and PI3K/Akt. In the mouse model, immunoreactivity for both gelatinases was concentrated around wound borders. EGFR transactivation by BDKRB1 agonist involves Src kinases family and ADAM17. In addition to extracellular matrix degradation, metalloproteases 2 and 9 regulate cell migration and differentiation, cell functions that are associated with the role of BDKRB1 in keratinocyte differentiation. Considering that BDKRB1 is up-regulated by inflammation and/or by cytokines that are abundant in the inflammatory milieu, more stable BDKRB1 agonists may be of therapeutic value to modulate wound healing. PMID:27093919

  7. Consumption of polyphenol-rich peach and plum juice prevents risk factors for obesity-related metabolic disorders and cardiovascular disease in Zucker rats.

    Science.gov (United States)

    Noratto, Giuliana; Martino, Hercia S D; Simbo, Sunday; Byrne, David; Mertens-Talcott, Susanne U

    2015-06-01

    Polyphenols from fruits have been implied in the prevention of risk factors for cardiometabolic disorders and cardiovascular disease. The purpose of this study was to investigate if the consumption of peach and plum juice has a protective effect against obesity and metabolic disorders that promote the development of cardiovascular diseases. Obese Zucker and lean rats were fed with peach, plum juice ad libitum or placebo. Body weight gain, biochemical markers and molecular markers for inflammation and cardiovascular disease in heart tissue were quantified. Results show that peach and plum juice consumption protected against a combination of obesity-induced metabolic disorders including hyperglycemia, insulin and leptin resistance, dyslipidemia and low-density lipoprotein oxidation. This was accompanied by a decreased expression of pro-atherogenic and pro-inflammatory biomarkers in plasma and heart tissues including intercellular cell adhesion molecule-1, monocyte chemotactic protein-1, NF-κB and foam cell adherence to aortic arches. In addition, peach and plum juice consumption decreased the levels of angiotensin II in plasma and its receptor Agtr1 in heart tissues, suggesting a role of peach and plum polyphenols as peroxisome proliferator-activated receptor-γ agonists. Furthermore, only plum juice significantly prevented body weight gain and increased the ratio high-density lipoprotein cholesterol/total cholesterol in plasma. This effect is most likely attributed to the plum's higher content of polyphenols (three times that of peach). Altogether, these results imply that cardioprotective effects can be achieved by replacing drinks high in sugar content with fruit juice rich in polyphenols in a diet. PMID:25801980

  8. Orthogonal factorizations of digraphs

    Institute of Scientific and Technical Information of China (English)

    Guizhen LIU

    2009-01-01

    Let G be a digraph with vertex set V(G) and arc set E(G) and let g = (g-,g+) and f = (f-, f+) be pairs of positive integer-valued functions defined on V(G) such that g-(x) ≤ f-(x) and g+(x) ≤ f+(x) for each x ∈ V(G). A (g, f)-factor of G is a spanning subdigraph H of G such that g-(x) ≤ idH(x) ≤ f-(x) and g+(x) ≤ odu(x) ≤ f+(x) for each x ∈ V(H); a (g, f)-factorization of G is a partition of E(G) into arc-disjoint (g, f)-factors. Let = {F1,F2,...,Fm} and H be a factorization and a subdigraph of G, respectively, is called k-orthogonal to H if each FI, 1 ≤ I ≤ m, has exactly k arcs in common with H. In this paper it is proved that every (mg+m-1, mf-m+1)-digraph has a (g, f)-factorization k-orthogonal to any given subdigraph with km arcs if k ≤ min{g-(x),g+(x)} for any x ∈ V(G) and that every (mg, mf)-digraph has a (g, f)-factorization orthogonal to any given directed m-star if 0 ≤ g(x) ≤ f(x) for any x ∈ V(G). The results in this paper are in some sense best possible.

  9. Graph factors modulo k

    DEFF Research Database (Denmark)

    Thomassen, Carsten

    2014-01-01

    We prove a general result on graph factors modulo k . A special case says that, for each natural number k , every (12k−7)-edge-connected graph with an even number of vertices contains a spanning subgraph in which each vertex has degree congruent to k modulo 2k.......We prove a general result on graph factors modulo k . A special case says that, for each natural number k , every (12k−7)-edge-connected graph with an even number of vertices contains a spanning subgraph in which each vertex has degree congruent to k modulo 2k....

  10. Factores de riesgo psicosocial

    OpenAIRE

    Fernández, Borja

    2012-01-01

    Tras un año de estudio de la Prevención de Riesgos Laborales he podido ir adquiriendo, todavía más, una clara concienciación sobre el estudio, supresión y mejora de los factores de riesgo que afectan a los trabajadores en la ejecución de su trabajo. Algo que es fácil de darse cuenta al entrar en profundidad en estas cuestiones, es de la escasa conciencia que tienen las organizaciones y los trabajadores sobre lo perjudiciales que pueden ser para su salud los factores de riesgo ergonómicos. ...

  11. STEREOTYPICAL FACTORS IN TOURISM

    Directory of Open Access Journals (Sweden)

    Cristina-Elena ALBU

    2013-06-01

    Full Text Available International tourism has grown rapidly nowdays, contributing to the growth of the global economy. The purpose of this essay is to identify and analyze stereotypical factors in the development of strategies concerning the offer for the tourism industry: the image of a tourist destination, brand, country of origin and customer behaviour. Documentary study was the research method used: representative articles were analysed, as recent as possible, to determine the factors mentioned above. Professionals in the industry of tourism need to understand cultural differences between tourists, as well as those of the host country, to be able to create tourist reception offers that live up to the standards expected by clients.

  12. The transcription factor encyclopedia.

    Science.gov (United States)

    Yusuf, Dimas; Butland, Stefanie L; Swanson, Magdalena I; Bolotin, Eugene; Ticoll, Amy; Cheung, Warren A; Zhang, Xiao Yu Cindy; Dickman, Christopher T D; Fulton, Debra L; Lim, Jonathan S; Schnabl, Jake M; Ramos, Oscar H P; Vasseur-Cognet, Mireille; de Leeuw, Charles N; Simpson, Elizabeth M; Ryffel, Gerhart U; Lam, Eric W-F; Kist, Ralf; Wilson, Miranda S C; Marco-Ferreres, Raquel; Brosens, Jan J; Beccari, Leonardo L; Bovolenta, Paola; Benayoun, Bérénice A; Monteiro, Lara J; Schwenen, Helma D C; Grontved, Lars; Wederell, Elizabeth; Mandrup, Susanne; Veitia, Reiner A; Chakravarthy, Harini; Hoodless, Pamela A; Mancarelli, M Michela; Torbett, Bruce E; Banham, Alison H; Reddy, Sekhar P; Cullum, Rebecca L; Liedtke, Michaela; Tschan, Mario P; Vaz, Michelle; Rizzino, Angie; Zannini, Mariastella; Frietze, Seth; Farnham, Peggy J; Eijkelenboom, Astrid; Brown, Philip J; Laperrière, David; Leprince, Dominique; de Cristofaro, Tiziana; Prince, Kelly L; Putker, Marrit; del Peso, Luis; Camenisch, Gieri; Wenger, Roland H; Mikula, Michal; Rozendaal, Marieke; Mader, Sylvie; Ostrowski, Jerzy; Rhodes, Simon J; Van Rechem, Capucine; Boulay, Gaylor; Olechnowicz, Sam W Z; Breslin, Mary B; Lan, Michael S; Nanan, Kyster K; Wegner, Michael; Hou, Juan; Mullen, Rachel D; Colvin, Stephanie C; Noy, Peter John; Webb, Carol F; Witek, Matthew E; Ferrell, Scott; Daniel, Juliet M; Park, Jason; Waldman, Scott A; Peet, Daniel J; Taggart, Michael; Jayaraman, Padma-Sheela; Karrich, Julien J; Blom, Bianca; Vesuna, Farhad; O'Geen, Henriette; Sun, Yunfu; Gronostajski, Richard M; Woodcroft, Mark W; Hough, Margaret R; Chen, Edwin; Europe-Finner, G Nicholas; Karolczak-Bayatti, Magdalena; Bailey, Jarrod; Hankinson, Oliver; Raman, Venu; LeBrun, David P; Biswal, Shyam; Harvey, Christopher J; DeBruyne, Jason P; Hogenesch, John B; Hevner, Robert F; Héligon, Christophe; Luo, Xin M; Blank, Marissa Cathleen; Millen, Kathleen Joyce; Sharlin, David S; Forrest, Douglas; Dahlman-Wright, Karin; Zhao, Chunyan; Mishima, Yuriko; Sinha, Satrajit; Chakrabarti, Rumela; Portales-Casamar, Elodie; Sladek, Frances M; Bradley, Philip H; Wasserman, Wyeth W

    2012-01-01

    Here we present the Transcription Factor Encyclopedia (TFe), a new web-based compendium of mini review articles on transcription factors (TFs) that is founded on the principles of open access and collaboration. Our consortium of over 100 researchers has collectively contributed over 130 mini review articles on pertinent human, mouse and rat TFs. Notable features of the TFe website include a high-quality PDF generator and web API for programmatic data retrieval. TFe aims to rapidly educate scientists about the TFs they encounter through the delivery of succinct summaries written and vetted by experts in the field. TFe is available at http://www.cisreg.ca/tfe.

  13. Factors stimulating content marketing

    Directory of Open Access Journals (Sweden)

    Naser Azad

    2016-02-01

    Full Text Available This paper presents an empirical investigation to determine factors influencing on content marketing in banking industry. The study designs a questionnaire consists of 40 questions in Likert scale and distributes it among 550 randomly selected regular customers of Bank Mellat in city of Tehran, Iran and 400 properly filled questionnaires are collected. Cronbach alphas for all components of the survey are well above desirable level. Using principle component analysis with Varimax rotation, the study has determined six factors influencing the most on content marketing including organization, details, having new ideas, quality, sensitivity and power while the last component contains only two subcomponents and is removed from the study.

  14. Anti-nutritional Factors.

    Science.gov (United States)

    2016-01-01

    Anti-nutritional factors such as trypsin inhibitor, phytic acid and cyanogen are as important as nutritional content of any edible plant part. The anti-nutritional factors can be defined as those substances generated in natural food substances by the normal metabolism of species and by different mechanisms (e.g. inactivation of some nutrients, diminution of the digestive process or metabolic utilization of feed) which exert effects contrary to optimum nutrition. Hence, trypsin inhibitor, phytic acid and cyanogens present in edibles with the methods in the chapter would be helpful. PMID:26939264

  15. Human factors in network security

    OpenAIRE

    Jones, Francis B.

    1991-01-01

    Human factors, such as ethics and education, are important factors in network information security. This thesis determines which human factors have significant influence on network security. Those factors are examined in relation to current security devices and procedures. Methods are introduced to evaluate security effectiveness by incorporating the appropriate human factors into network security controls

  16. Irrational factor races

    Indian Academy of Sciences (India)

    Sneha Chaubey; Milenda Lanius; Alexandru Zaharescu

    2014-11-01

    We investigate the behavior of the sum of the irrational factor function over arithmetic progressions. We first establish a general asymptotic formula for such a sum, and then obtain some further results in the case of arithmetic progressions 3 ± 1.

  17. Introduction to human factors

    International Nuclear Information System (INIS)

    Some background is given on the field of human factors. The nature of problems with current human/computer interfaces is discussed, some costs are identified, ideal attributes of graceful system interfaces are outlined, and some reasons are indicated why it's not easy to fix the problems

  18. Psychosomatic factors in pruritus

    OpenAIRE

    Tey, Hong Liang; Wallengren, Joanna; Yosipovitch, Gil

    2013-01-01

    Pruritus and psyche are intricately and reciprocally related, with psychophysiological evidence and psychopathological explanations helping us to understand their complex association. Their interaction may be conceptualized and classified into 3 groups: pruritic diseases with psychiatric sequelae, pruritic diseases aggravated by psychosocial factors, and psychiatric disorders causing pruritus. Management of chronic pruritus is directed at treating the underlying causes and adopting a multidis...

  19. On the Saltzman factor

    NARCIS (Netherlands)

    Huygen, C.; Lanting, R.W.

    1975-01-01

    The nitrite equivalent of nitrogen dioxide in its determination in polluted air by means of a Griess type reagent is commonly called the Saltzman factor. Values ranging from 0.5 to 1.000 have been reported, but discussion about the 'right' value continues. The results of experimental calculations ar

  20. Affective Factors: Anxiety

    Science.gov (United States)

    Tasnimi, Mahshad

    2009-01-01

    Affective factors seem to play a crucial role in success or failure in second language acquisition. Negative attitudes can reduce learners' motivation and harm language learning, while positive attitudes can do the reverse. Discovering students' attitudes about language will help both teacher and student in teaching learning process. Anxiety is…

  1. Functional Maximum Autocorrelation Factors

    DEFF Research Database (Denmark)

    Larsen, Rasmus; Nielsen, Allan Aasbjerg

    2005-01-01

    \\verb+~+\\$\\backslash\\$cite{ramsay97} to functional maximum autocorrelation factors (MAF)\\verb+~+\\$\\backslash\\$cite{switzer85,larsen2001d}. We apply the method to biological shapes as well as reflectance spectra. {\\$\\backslash\\$bf Methods}. MAF seeks linear combination of the original variables that maximize autocorrelation between...

  2. Prognostic factors in oligodendrogliomas

    DEFF Research Database (Denmark)

    Westergaard, L; Gjerris, F; Klinken, L

    1997-01-01

    An outcome analysis was performed on 96 patients with pure cerebral oligodendrogliomas operated in the 30-year period 1962 to 1991. The most important predictive prognostic factors were youth and no neurological deficit, demonstrated as a median survival for the group younger than 20 years of 17...

  3. Hyperglycemia: a prothrombotic factor?

    NARCIS (Netherlands)

    B.A. Lemkes; J. Hermanides; J.H. Devries; F. Holleman; J.C.M. Meijers; J.B.L. Hoekstra

    2010-01-01

    Diabetes mellitus is characterized by a high risk of atherothrombotic events. What is more, venous thrombosis has also been found to occur more frequently in this patient group. This prothrombotic condition in diabetes is underpinned by laboratory findings of elevated coagulation factors and impaire

  4. Heart Disease Risk Factors

    Science.gov (United States)

    ... Hearts® WISEWOMAN Program Other Chronic Disease Topics Diabetes Nutrition Obesity Physical Activity Stroke Heart Disease Risk Factors Recommend ... Hearts® WISEWOMAN Program Other Chronic Disease Topics Diabetes Nutrition Obesity Physical Activity Stroke File Formats Help: How do ...

  5. Model Correction Factor Method

    DEFF Research Database (Denmark)

    Christensen, Claus; Randrup-Thomsen, Søren; Morsing Johannesen, Johannes

    1997-01-01

    of the model correction factor method, is that in simpler form not using gradient information on the original limit state function or only using this information once, a drastic reduction of the number of limit state evaluation is obtained together with good approximations on the reliability. Methods...

  6. FRUIT NUTRITIVE FACTOR NETWORK

    Institute of Scientific and Technical Information of China (English)

    Yanqing QU; Yumei JIANG; Daren HE

    2009-01-01

    As an research example of the widely existing cooperation-competition systems, the authors present an empirical investigation on a fruit nutritive factor network. It is described by a node-weighted bipartite graph. The fruit nutritive factors are defined as the nodes, and two nodes are connected by an edge if at least one fruit contains these two nutritive factors. The fruits are defined as the collaboration acts. The node-weight Writ, which signifies the "importance degree" of each actor node, is defined as the content of a nutritive factor in a fruit. The empirical investigation results show some unique features.The node-weight distributions take so-called "shifted power law" function forms, but the act-weight distribution takes a normal form. The degree and act-degree distributions show impulsive-spectrum like forms. These observations may be helpful for the study of fruits. The network description method proposed in this article may be universal for a kind of cooperation-competition systems.

  7. Introduction to human factors

    Energy Technology Data Exchange (ETDEWEB)

    Winters, J.M.

    1988-03-01

    Some background is given on the field of human factors. The nature of problems with current human/computer interfaces is discussed, some costs are identified, ideal attributes of graceful system interfaces are outlined, and some reasons are indicated why it's not easy to fix the problems. (LEW)

  8. Nucleon Form Factors

    Energy Technology Data Exchange (ETDEWEB)

    Kees de Jager

    2002-10-01

    A review of data on the nucleon electro-weak form factors in the space-like region is presented. Recent results from experiments using polarized beams and either polarized targets or nucleon recoil polarimeters have yielded a significant improvement on the precision of the electromagnetic data obtained with the traditional Rosenbluth separation. An outlook is presented of planned experiments.

  9. Fibroblast growth factors 1 and 2 in cerebrospinal fluid are associated with HIV disease, methamphetamine use, and neurocognitive functioning

    Directory of Open Access Journals (Sweden)

    Bharti AR

    2016-04-01

    Full Text Available Ajay R Bharti,1 Steven Paul Woods,2 Ronald J Ellis,3 Mariana Cherner,2 Debra Rosario,3 Michael Potter,3 Robert K Heaton,2 Ian P Everall,4 Eliezer Masliah,5 Igor Grant,2 Scott L Letendre1 On behalf of the Translational Methamphetamine AIDS Research Center Group 1Department of Medicine, 2Department of Psychiatry, 3Department of Neurosciences, University of California San Diego, San Diego, CA, USA; 4Department of Psychiatry, University of Melbourne, Victoria, Australia; 5Department of Pathology, University of Californa San Diego, San Diego, CA, USA Background: Human immunodeficiency virus (HIV and methamphetamine use commonly affect neurocognitive (NC functioning. We evaluated the relationships between NC functioning and two fibroblast growth factors (FGFs in volunteers who differed in HIV serostatus and methamphetamine dependence (MAD. Methods: A total of 100 volunteers were categorized into four groups based on HIV serostatus and MAD in the prior year. FGF-1 and FGF-2 were measured in cerebrospinal fluid by enzyme-linked immunosorbent assays along with two reference biomarkers (monocyte chemotactic protein [MCP]-1 and neopterin. Comprehensive NC testing was summarized by global and domain impairment ratings. Results: Sixty-three volunteers were HIV+ and 59 had a history of MAD. FGF-1, FGF-2, and both reference biomarkers differed by HIV and MAD status. For example, FGF-1 levels were lower in subjects who had either HIV or MAD than in HIV– and MAD– controls (P=0.003. Multivariable regression identified that global NC impairment was associated with an interaction between FGF-1 and FGF-2 (model R2=0.09, P=0.01: higher FGF-2 levels were only associated with neurocognitive impairment among subjects who had lower FGF-1 levels. Including other covariates in the model (including antidepressant use strengthened the model (model R2=0.18, P=0.004 but did not weaken the association with FGF-1 and FGF-2. Lower FGF-1 levels were associated with impairment

  10. Factor Trade and Goods Trade

    OpenAIRE

    Svensson, Lars E. O.

    1982-01-01

    Previous work by Dixit and Woodland on the effect of inter-country factor endowment differences on goods trade is extended to include simultaneous factor trade and goods trade. The goods trade pattern with factor trade is compared to that without factor trade. It is for instance shown that goods trade and factor trade may be substitutes or complements, depending upon whether traded and nontraded factors are "cooperative" or "non-cooperative." The asymmetry between the effects of differences i...

  11. Precipitating factors of asthma.

    Science.gov (United States)

    Lee, T H

    1992-01-01

    Asthma is characterised by bronchial hyperresponsiveness. This feature of the asthmatic diathesis predisposes patients to wheezing in response to a number of different factors. These precipitating factors include specific allergen acting via sensitised mediator cells through an IgE-dependent mechanism. There are irritants which may work through a non-specific manner, or stimuli such as exercise and hyperventilation, which probably also act through mediator release via a non-IgE-dependent manner. The mechanism whereby physical stimuli such as exercise induce bronchoconstriction is of interest, because it increases the context in which the mast cell may participate in acute asthmatic bronchoconstriction. Respiratory infections also commonly provoke asthma, especially in infants and may, indeed, precipitate the asthmatic state itself. Finally, drugs can often trigger asthma attacks and the mechanisms of asthma precipitated by non-steroidal anti-inflammatory drugs such as aspirin have been the subject of recent research.

  12. On braid monodromy factorizations

    Energy Technology Data Exchange (ETDEWEB)

    Kharlamov, V M [Institut de Recherche Matematique Avanee Universite Louis Pasteur et CNRS 7 rue Rene Descartes (France); Kulikov, Vik S [Steklov Mathematical Institute, Russian Academy of Sciences (Russian Federation)

    2003-06-30

    We introduce and develop a language of semigroups over the braid groups to study the braid monodromy factorizations (bmf's) of plane algebraic curves and other related objects. As an application, we give a new proof of Orevkov's theorem on the realization of bmf's over a disc by algebraic curves and show that the complexity of such a realization cannot be bounded in terms of the types of factors of the bmf. We also prove that the type of a bmf distinguishes Hurwitz curves with singularities of inseparable type up to H-isotopy and J-holomorphic cuspidal curves in CP{sup 2} up to symplectic isotopy.

  13. The focus factor

    DEFF Research Database (Denmark)

    Nicolaisen, Jeppe; Frandsen, Tove Faber

    2015-01-01

    is demonstrated on a selection of general science journals and on a selection of medical journals. The reference lists of each journal are compared year by year, and the percentage of re-citations is calculated by dividing the number of re-citations with the total number of citations each year. Analysis......Introduction. We present a new bibliometric indicator to measure journal specialisation over time, named the focus factor. This new indicator is based on bibliographic coupling and counts the percentage of re-citations given in subsequent years. Method. The applicability of the new indicator....... To validate re-citations as caused by specialisation, other possible causes were measured and correlated (obsolescence, journal self-citations and number of references). Results. The results indicate that the focus factor is capable of distinguishing between general and specialised journals and thus...

  14. FACTORING IN FORFAITING - PRIMERJAVA

    OpenAIRE

    Kaučič, Urša

    2011-01-01

    V tem diplomskem delu bom predstavila dve vrsti modernih finančnih transakcij, natančneje dva moderna tipa pogodb avtonomnega gospodarskega prava, to sta factoring in forfaiting. Analiza je namenjena tako pojmu in razvoju obeh omenjenih vrst, kot tudi pogodbi o factoringu in pogodbi o forfaitingu. Pozornost je namenjena primerjavi med pojmoma factoringa in forfaitinga, ter osvetlitvi podobnosti in razlik med njima glede na klasifikacijo obeh pogodb, glede na stranke, ki pri poslih sodelujejo,...

  15. Factors determining working satisfaction

    OpenAIRE

    Nováčková, Radka

    2014-01-01

    This thesis is focused on the job satisfaction of employees in the selected organization. This organization is a company Cinema City Czech a limited lability. Specifically the thesis deals with job satisfaction of employees in multiplexes in six prague´s locations. The teoretical part is based on description of individual factors that affect job satisfaction. These are the condition of workplace, job content, financial rewards etc. Thesis is also focused on the motivation and important b...

  16. Factors stimulating content marketing

    OpenAIRE

    Naser Azad; Seyed Mohsen Seyed AliAkbar; Sima Zomorodian

    2016-01-01

    This paper presents an empirical investigation to determine factors influencing on content marketing in banking industry. The study designs a questionnaire consists of 40 questions in Likert scale and distributes it among 550 randomly selected regular customers of Bank Mellat in city of Tehran, Iran and 400 properly filled questionnaires are collected. Cronbach alphas for all components of the survey are well above desirable level. Using principle component analysis with Varimax rotation, the...

  17. Neonatal Stroke : Risk Factors

    OpenAIRE

    2005-01-01

    Neonatal stroke refers to cerebrovascular events between 28 weeks of gestational age and 28 days postnatal and includes thromboembolic cerebral infarction and all kinds of intracranial haemorrhage. Neonatal stroke may contribute to severe neurological deficit, such as cerebral palsy and even death. International reports suggest the incidence to be approximately 1/4000 live births per year (1). There are several etiological hypothesises regarding risk factors, such as maternal, obstetrical...

  18. Factors Affecting Students' Performance

    OpenAIRE

    Harb, Nasri; El-Shaarawi, Ahmed

    2006-01-01

    Determinants of students' performance have been the subject of ongoing debate among educators, academics, and policy makers. There have been many studies that sought to examine this issue and their findings point out to hard work, previous schooling, parents’ education, family income and self motivation as factors that have a significant effect on the students GPA. Most of those studies have focused on students' performance in the U.S. and Europe. However, since cultural differences may play ...

  19. Factors Affecting Students' Performance

    OpenAIRE

    Harb, Nasri; El-Shaarawi, Ahmed

    2006-01-01

    Determinants of students' performance have been the subject of ongoing debate among educators, academics, and policy makers. There have been many studies that sought to examine this issue and their findings point out to hard work, previous schooling, parents’ education, family income and self motivation as factors that have a significant effect on the students GPA. Most of those studies have focused on students' performance in the U.S. and Europe. However, since cultural differences may p...

  20. Fano factor estimation.

    Science.gov (United States)

    Rajdl, Kamil; Lansky, Petr

    2014-02-01

    Fano factor is one of the most widely used measures of variability of spike trains. Its standard estimator is the ratio of sample variance to sample mean of spike counts observed in a time window and the quality of the estimator strongly depends on the length of the window. We investigate this dependence under the assumption that the spike train behaves as an equilibrium renewal process. It is shown what characteristics of the spike train have large effect on the estimator bias. Namely, the effect of refractory period is analytically evaluated. Next, we create an approximate asymptotic formula for the mean square error of the estimator, which can also be used to find minimum of the error in estimation from single spike trains. The accuracy of the Fano factor estimator is compared with the accuracy of the estimator based on the squared coefficient of variation. All the results are illustrated for spike trains with gamma and inverse Gaussian probability distributions of interspike intervals. Finally, we discuss possibilities of how to select a suitable observation window for the Fano factor estimation. PMID:24245675

  1. Accidents - personal factors

    Energy Technology Data Exchange (ETDEWEB)

    Zaitsev, S.L.; Tsygankov, A.V.

    1982-03-01

    This paper evaluates influence of selected personal factors on accident rate in underground coal mines in the USSR. Investigations show that so-called organizational factors cause from 80 to 85% of all accidents. About 70% of the organizational factors is associated with social, personal and economic features of personnel. Selected results of the investigations carried out in Donbass mines are discussed. Causes of miner dissatisfaction are reviewed: 14% is caused by unsatisfactory working conditions, 21% by repeated machine failures, 16% by forced labor during days off, 14% by unsatisfactory material supply, 16% by hard physical labor, 19% by other reasons. About 25% of miners injured during work accidents are characterized as highly professionally qualified with automatic reactions, and about 41% by medium qualifications. About 60% of accidents is caused by miners with less than a 3 year period of service. About 15% of accidents occurs during the first month after a miner has returned from a leave. More than 30% of accidents occurs on the first work day after a day or days off. Distribution of accidents is also presented: 19% of accidents occurs during the first 2 hours of a shift, 36% from the second to the fourth hour, and 45% occurs after the fourth hour and before the shift ends.

  2. Human Factors Review Plan

    Energy Technology Data Exchange (ETDEWEB)

    Paramore, B.; Peterson, L.R. (eds.)

    1985-12-01

    ''Human Factors'' is concerned with the incorporation of human user considerations into a system in order to maximize human reliability and reduce errors. This Review Plan is intended to assist in the assessment of human factors conditions in existing DOE facilities. In addition to specifying assessment methodologies, the plan describes techniques for improving conditions which are found to not adequately support reliable human performance. The following topics are addressed: (1) selection of areas for review describes techniques for needs assessment to assist in selecting and prioritizing areas for review; (2) human factors engineering review is concerned with optimizing the interfaces between people and equipment and people and their work environment; (3) procedures review evaluates completeness and accuracy of procedures, as well as their usability and management; (4) organizational interface review is concerned with communication and coordination between all levels of an organization; and (5) training review evaluates training program criteria such as those involving: trainee selection, qualification of training staff, content and conduct of training, requalification training, and program management.

  3. Human Factors Review Plan

    International Nuclear Information System (INIS)

    ''Human Factors'' is concerned with the incorporation of human user considerations into a system in order to maximize human reliability and reduce errors. This Review Plan is intended to assist in the assessment of human factors conditions in existing DOE facilities. In addition to specifying assessment methodologies, the plan describes techniques for improving conditions which are found to not adequately support reliable human performance. The following topics are addressed: (1) selection of areas for review describes techniques for needs assessment to assist in selecting and prioritizing areas for review; (2) human factors engineering review is concerned with optimizing the interfaces between people and equipment and people and their work environment; (3) procedures review evaluates completeness and accuracy of procedures, as well as their usability and management; (4) organizational interface review is concerned with communication and coordination between all levels of an organization; and (5) training review evaluates training program criteria such as those involving: trainee selection, qualification of training staff, content and conduct of training, requalification training, and program management

  4. Perinatal risk factors for strabismus

    DEFF Research Database (Denmark)

    Torp-Pedersen, Tobias; Boyd, Heather A; Poulsen, Gry;

    2010-01-01

    Little is known about the aetiological factors underlying strabismus. We undertook a large cohort study to investigate perinatal risk factors for strabismus, overall and by subtype.......Little is known about the aetiological factors underlying strabismus. We undertook a large cohort study to investigate perinatal risk factors for strabismus, overall and by subtype....

  5. Risk Factors for Eating Disorders

    Science.gov (United States)

    Striegel-Moore, Ruth H.; Bulik, Cynthia M.

    2007-01-01

    The authors review research on risk factors for eating disorders, restricting their focus to studies in which clear precedence of the hypothesized risk factor over onset of the disorder is established. They illustrate how studies of sociocultural risk factors and biological factors have progressed on parallel tracks and propose that major advances…

  6. A New Factorization Method to Factorize RSA Public Key Encryption

    Directory of Open Access Journals (Sweden)

    Bhagvant Ram Ambedkar

    2011-11-01

    Full Text Available The security of public key encryption such as RSA scheme relied on the integer factoring problem. The security of RSA algorithm is based on positive integer N, because each transmitting node generates pair of keys such as public and private. Encryption and decryption of any message depends on N. Where, N is the product of two prime numbers and pair of key generation is dependent on these prime numbers. The factorization of N is very intricate. In this paper a New Factorization method is proposed to obtain the factor of positive integer N. The proposed work focuses on factorization of all trivial and nontrivial integer numbers and requires fewer steps for factorization process of RSA modulus N. The New Factorization method is based on Pollard rho factorization method. Experimental results shown that factorization speed is fast as compare existing methods.

  7. Milestones and Impact Factors

    Directory of Open Access Journals (Sweden)

    Grandjean Philippe

    2010-07-01

    Full Text Available Abstract Environmental Health has just received its first Impact Factor by Thomson ISI. At a level of 2.48, this achievement is quite satisfactory and places Environmental Health in the top 25% of environmental science journals. When the journal was launched in 2002, it was still unclear whether the Open Access publishing model could be made into a viable commercial enterprise within the biomedical field. During the past eight years, Open Access journals have become widely available, although still covering only about 15% of journal titles. Major funding agencies and institutions, including prominent US universities, now require that researchers publish in Open Access journals. Because of the profound role of scientific journals for the sharing of results and communication between researchers, the advent of Open Access may be of as much significance as the transition from handwriting to printing via moveable type. As Environmental Health is an electronic Open Access journal, the numbers of downloads at the journal website can be retrieved. The top-20 list of articles most frequently accessed shows that all of them have been downloaded over 10,000 times. Back in 2002, the first article published was accessed only 49 times during the following month. A year later, the server had over 1,000 downloads per month, and now the total number of monthly downloads approaches 50,000. These statistics complement the Impact Factor and confirm the viability of Open Access in our field of research. The advent of digital media and its decentralized mode of distribution - the internet - have dramatically changed the control and financing of scientific information dissemination, while facilitating peer review, accelerating editorial handling, and supporting much needed transparency. Both the meaning and means of "having an impact" are therefore changing, as will the degree and way in which scientific journals remain "factors" in that impact.

  8. Accidents and human factors

    International Nuclear Information System (INIS)

    When the TMI accident occurred it was 4 a.m., an hour when the error potential of the operators would have been very high. The frequency of car and train accidents in Japan is also highest between 4 a.m. and 6 a.m. The error potential may be classified into five phases corresponding to the electroencephalogramic pattern (EEG). At phase 0, when the delta wave appears, a person is unconscious and in deep sleep; at phase I, when the theta wave appears, he is very tired, sleepy and subnormal; at phase II, when the alpha wave appears, he is normal, relaxed and passive; at phase III, when the beta wave appears, he is normal, clear-minded and active; at phase IV, when the strong beta or epileptic wave appears, he is hypernormal, excited and incapable of normal judgement. Should an accident occur at phase II, the brain condition may jump to phase IV. At this phase the error or accident potential is maximum. The response of the human brain to different types of noises and signals may vary somewhat for different individuals and for different groups of people. Therefore, the possibility that such differences in brain functions may influence the mental structure would be worthy of consideration in human factors and in the design of man-machine systems. Human reliability and performance would be affected by many factors: medical, physiological and psychological, etc. The uncertainty involved in human factors may not necessarily be probabilistic, but fuzzy. Therefore, it would be important to develop a theory by which both non-probabilistic uncertainties, or fuzziness, of human factors and the probabilistic properties of machines can be treated consistently. From the mathematical point of view, probabilistic measure is considered a special case of fuzzy measure. Therefore, fuzzy set theory seems to be an effective tool for analysing man-machine systems. To minimize human error and the possibility of accidents, new safety systems should not only back up man and make up for his

  9. Tiled QR factorization algorithms

    OpenAIRE

    Bouwmeester, Henricus; Jacquelin, Mathias; Langou, Julien; Robert, Yves

    2011-01-01

    This work revisits existing algorithms for the QR factorization of rectangular matrices composed of p-by-q tiles, where p >= q. Within this framework, we study the critical paths and performance of algorithms such as Sameh and Kuck, Modi and Clarke, Greedy, and those found within PLASMA. Although neither Modi and Clarke nor Greedy is optimal, both are shown to be asymptotically optimal for all matrices of size p = q^2 f(q), where f is any function such that \\lim_{+\\infty} f= 0. This novel and...

  10. Cultural Factors in Reading

    Institute of Scientific and Technical Information of China (English)

    孔敏

    2005-01-01

    Reading is a basic ability in learning English and reading comprehension exercise is a common way to assess this ability.Since reading is a communicative activity between author and reader in written form,there are some different rules and regulations of this communication in different countries.Therefore,cultural factors,existing in reading,decide,help,and influence the percentage of the right answers.This article attempts to analyze the effects of cultural differences in reading and the barriers in comprehension,and aims to improve students awareness of cultural differences in reading.

  11. Factors regulating cheese shreddability.

    Science.gov (United States)

    Childs, J L; Daubert, C R; Stefanski, L; Foegeding, E A

    2007-05-01

    Two sets of cheeses were evaluated to determine factors that affect shred quality. The first set of cheeses was made up of 3 commercial cheeses, Monterey Jack, Mozzarella, and process. The second set of cheeses was made up of 3 Mozzarella cheeses with varying levels of protein and fat at a constant moisture content. A shred distribution of long shreds, short shreds, and fines was obtained by shredding blocks of cheese in a food processor. A probe tack test was used to directly measure adhesion of the cheese to a stainless-steel surface. Surface energy was determined based on the contact angles of standard liquids, and rheological characterization was done by a creep and recovery test. Creep and recovery data were used to calculate the maximum and initial compliance and retardation time. Shredding defects of fines and adhesion to the blade were observed in commercial cheeses. Mozzarella did not adhere to the blade but did produce the most fines. Both Monterey Jack and process cheeses adhered to the blade and produced fines. Furthermore, adherence to the blade was correlated positively with tack energy and negatively with retardation time. Mozzarella cheese, with the highest fat and lowest protein contents, produced the most fines but showed little adherence to the blade, even though tack energy increased with fat content. Surface energy was not correlated with shredding defects in either group of cheese. Rheological properties and tack energy appeared to be the key factors involved in shredding defects. PMID:17430914

  12. Enhanced target factor analysis.

    Science.gov (United States)

    Rostami, Akram; Abdollahi, Hamid; Maeder, Marcel

    2016-03-10

    Target testing or target factor analysis, TFA, is a well-established soft analysis method. TFA answers the question whether an independent target test vector measured at the same wavelengths as the collection of spectra in a data matrix can be excluded as the spectrum of one of the components in the system under investigation. Essentially, TFA cannot positively prove that a particular test spectrum is the true spectrum of one of the components, it can, only reject a spectrum. However, TFA will not reject, or in other words TFA will accept, many spectra which cannot be component spectra. Enhanced Target Factor Analysis, ETFA addresses the above problem. Compared with traditional TFA, ETFA results in a significantly narrower range of positive results, i.e. the chance of a false positive test result is dramatically reduced. ETFA is based on feasibility testing as described in Refs. [16-19]. The method has been tested and validated with computer generated and real data sets. PMID:26893084

  13. Monocyte chemotactic protein-1 and other inflammatory parameters in Bernese Mountain dogs with disseminated histiocytic sarcoma

    DEFF Research Database (Denmark)

    Nielsen, Lise Nikolic; Kjelgaard-Hansen, Mads; Kristensen, Annemarie Thuri

    2013-01-01

    The interaction between cancer and the immune system, and the production of cytokines by the tumour itself have been associated with altered levels of cytokines in human cancer patients. Bernese Mountain dogs with disseminated histiocytic sarcoma (DHS) show vague and non-specific clinical signs....... Although histiocytes can secrete cytokines in response to inflammatory stimuli, serum cytokine concentrations in dogs with DHS have not previously been investigated. The aim of this study was to evaluate the immunological state of untreated Bernese Mountain dogs with DHS by assessing multiple serum...... cytokines and to correlate these with other inflammatory markers. As a prospective case control study, 17 Bernese Mountain dogs with DHS were included along with 18 healthy controls (12 Bernese Mountain dogs and 6 dogs of various breeds). Blood samples were examined for fibrinogen, C-reactive protein (CRP...

  14. The GIT–PIX complexes regulate the chemotactic response of rat basophilic leukaemia cells

    OpenAIRE

    Gavina, Manuela; Za, Lorena; Molteni, Raffaella; Pardi, Ruggero; Curtis, Ivan de

    2010-01-01

    Background information. Cell motility entails the reorganization of the cytoskeleton and membrane trafficking for effective protrusion. The GIT–PIX protein complexes are involved in the regulation of cell motility and adhesion and in the endocytic traffic of members of the family of G-protein-coupled receptors. We have investigated the function of the endogenous GIT complexes in the regulation of cell motility stimulated by fMLP (formyl-Met-Leu-Phe) peptide, in a rat basophilic leukaemia RBL-...

  15. A Worldwide Competition to Compare the Speed and Chemotactic Accuracy of Neutrophil-Like Cells

    NARCIS (Netherlands)

    Skoge, Monica; Wong, Elisabeth; Hamza, Bashar; Bae, Albert; Martel, Joseph; Kataria, Rama; Keizer-Gunnink, Ineke; Kortholt, Arjan; Van Haastert, Peter J.M.; Charras, Guillaume; Janetopoulos, Christopher; Irimia, Daniel

    2016-01-01

    Chemotaxis is the ability to migrate towards the source of chemical gradients. It underlies the ability of neutrophils and other immune cells to hone in on their targets and defend against invading pathogens. Given the importance of neutrophil migration to health and disease, it is crucial to unders

  16. Structure of bacterial cytoplasmic chemoreceptor arrays and implications for chemotactic signaling.

    Science.gov (United States)

    Briegel, Ariane; Ladinsky, Mark S; Oikonomou, Catherine; Jones, Christopher W; Harris, Michael J; Fowler, Daniel J; Chang, Yi-Wei; Thompson, Lynmarie K; Armitage, Judith P; Jensen, Grant J

    2014-01-01

    Most motile bacteria sense and respond to their environment through a transmembrane chemoreceptor array whose structure and function have been well-studied, but many species also contain an additional cluster of chemoreceptors in their cytoplasm. Although the cytoplasmic cluster is essential for normal chemotaxis in some organisms, its structure and function remain unknown. Here we use electron cryotomography to image the cytoplasmic chemoreceptor cluster in Rhodobacter sphaeroides and Vibrio cholerae. We show that just like transmembrane arrays, cytoplasmic clusters contain trimers-of-receptor-dimers organized in 12-nm hexagonal arrays. In contrast to transmembrane arrays, however, cytoplasmic clusters comprise two CheA/CheW baseplates sandwiching two opposed receptor arrays. We further show that cytoplasmic fragments of normally transmembrane E. coli chemoreceptors form similar sandwiched structures in the presence of molecular crowding agents. Together these results suggest that the 12-nm hexagonal architecture is fundamentally important and that sandwiching and crowding can replace the stabilizing effect of the membrane. DOI: http://dx.doi.org/10.7554/eLife.02151.001.

  17. Butyrate regulates the expression of inflammatory and chemotactic cytokines in human acute leukemic cells during apoptosis.

    Science.gov (United States)

    Pulliam, Stephanie R; Pellom, Samuel T; Shanker, Anil; Adunyah, Samuel E

    2016-08-01

    Butyrate is a histone deacetylase inhibitor implicated in many studies as a potential therapy for various forms of cancer. High concentrations of butyrate (>1.5mM) have been shown to activate apoptosis in several cancer cell lines including prostate, breast, and leukemia. Butyrate is also known to influence multiple signaling pathways that are mediators of cytokine production. The purpose of this study was to evaluate the impact of high concentrations of butyrate on the cancer microenvironment vis-à-vis apoptosis, cellular migration, and capacity to modulate cytokine expression in cancer cells. The results indicate that high concentrations of butyrate induced a 2-fold activation of caspase-3 and reduced cell viability by 60% in U937 leukemia cells. Within 24h, butyrate significantly decreased the levels of chemokines CCL2 and CCL5 in HL-60 and U937 cells, and decreased CCL5 in THP-1 leukemia cells. Differential effects were observed in treatments with valproic acid for CCL2 and CCL5 indicating butyrate-specificity. Many of the biological effects examined in this study are linked to activation of the AKT and MAPK signaling pathways; therefore, we investigated whether butyrate alters the levels of phosphorylated forms of these signaling proteins and how it correlated with the expression of chemokines. The results show that butyrate may partially regulate CCL5 production via p38 MAPK. The decrease in p-ERK1/2 and p-AKT levels correlated with the decrease in CCL2 production. These data suggest that while promoting apoptosis, butyrate has the potential to influence the cancer microenvironment by inducing differential expression of cytokines. PMID:27253488

  18. Cytokines secreted by macrophages isolated from tumor microenvironment of inflammatory breast cancer patients possess chemotactic properties

    OpenAIRE

    Mohamed, Mona M.; El-Ghonaimy, Eslam A.; Nouh, Mohamed A.; Schneider, Robert J.; Sloane, Bonnie F.; El-Shinawi, Mohamed

    2013-01-01

    Although there is a growing literature describing the role of macrophages in breast cancer, the role of macrophages in inflammatory breast cancer (IBC) is unclear. The aim of present study was to isolate and characterize tumor associated macrophages of IBC and non-IBC patients and define their role in IBC. Tumor infiltrating monocytes/macrophages (CD14+ and CD68+) were measured by immunohistochem-istry using specific monoclonal antibodies. Blood drained from axillary vein tributaries was coll...

  19. Collagen and Collagen-derived Fragments Are Chemotactic for Tumor Cells

    OpenAIRE

    Mundy, Gregory R; Demartino, Sandra; Rowe, David W.

    1981-01-01

    Organs that are rich in collagen such as liver, lungs, and bone are frequently sites of tumor cell metastasis. In this study, we have found that cultured tumor cells of human and rat origin migrated unidirectionally in response to collagen in vitro. Synthetic di- and tri-peptides that contained amino acid sequences found frequently in the collagen helix caused similar effects. These results are consistent with the hypothesis that collagen or collagen fragments released during connective tissu...

  20. Amino acid efflux in response to chemotactic and osmotic signals in Bacillus subtilis.

    OpenAIRE

    Wong, L S; Johnson, M. S.; Sandberg, L. B.; Taylor, B L

    1995-01-01

    We observed a large efflux of nonvolatile radioactivity from Bacillus subtilis in response to the addition of 31 mM butyrate or the withdrawal of 0.1 M aspartate in a flow assay. The major nonvolatile components effluxed were methionine, proline, histidine, and lysine. In studies of the release of volatile radioactivity in chemotaxis by B. subtilis cells that had been labeled with [3H]methionine, the breakdown of methionine to methanethiol can contribute substantially to the volatile radioact...

  1. Indoleamine 2, 3-dioxygenase (IDO) is essential for dendritic cell activation and chemotactic responsiveness to chemokines

    Institute of Scientific and Technical Information of China (English)

    Shih Ling HWANG; Nancy Pei-Yee CHUNG; Jacqueline Kwai-Yi CHAN; Chen-Lung Steve LIN

    2005-01-01

    Indoleamine 2, 3-dioxygenase (IDO) is a rate-limiting enzyme for the tryptophan catabolism. In human and murine cells, IDO inhibits antigen-specific T cell proliferation in vitro and suppresses T cell responses to fetal alloantigens during murine pregnancy. In mice, IDO expression is an inducible feature of specific subsets of dendritic cells (DCs),and is important for T cell regulatory properties. However, the effect of IDO and tryptophan deprivation on DC functions remains unknown. We report here that when tryptophan utilization was prevented by a pharmacological inhibitor of IDO, 1-methyl tryptophan (1MT), DC activation induced by pathogenic stimulus lipopolysaccharide (LPS) or inflammatory cytokine TNF-α was inhibited both phenotypically and functionally. Such an effect was less remarkable when DC was stimulated by a physiological stimulus, CD40 ligand. Tryptophan deprivation during DC activation also regulated the expression of CCR5 and CXCR4, as well as DC responsiveness to chemokines. These results suggest that tryptophan usage in the microenvironment is essential for DC maturation, and may also play a role in the regulation of DC migratory behaviors.

  2. Role of RhoA in platelet-derived growth factor-BB-induced migration of rat hepatic stellate cells

    Institute of Scientific and Technical Information of China (English)

    LI Lei; LI Jing; WANG Ji-yao; YANG Chang-qing; JIA Ming-lei; JIANG Wei

    2010-01-01

    Background Although the migration of hepatic stellate cells (HSCs) is essential for hepatic fibrotic response, the detailed mechanisms involved are poorly understood. The aim of this study was to examine the role of Rho GTPases (especially RhoA) in platelet-derived growth factor (PDGF)-BB-induced migration of HSCs.Methods The migration of primary rat HSCs was evaluated using transwell Boyden chamber, while cytoskeletal changes were visualized by immunofluorescence staining of intracellular actins and vinculin. Quantitative real-time PCR and Western blotting analysis were used to detect the expression of Rho GTPases (RhoA, Rac1 and Cdc42) within HSCs and their activation was determined by glutathione S-transferase pull-down assay. Finally, the effects of RhoA on PDGF-BB-induced cell migration and cytoskeletal remodeling were analyzed using HSC-T6 cells stably transfected with constitutively active (CA, Q63L) or dominant negative (DN, T19N) RhoA mutants. Data were analyzed using SPSS 16.0 software. Student's t test was used to analyze differences between two groups and one-way analysis of variance (ANOVA) was used among multiple groups.Results Rapid cytoskeletal remodeling led to a significant increase in the motility of primary rat HSCs after haptotactic (direct) and chemotactic (indirect) stimulation by PDGF-BB. PDGF-BB caused a dramatic elevation in the levels of both total and active RhoA protein. However, the levels of mRNA for Rho GTPases, including RhoA, Rac1 and Cdc42, were unaffected. Furthermore, PDGF-BB induced increased formation of stress fibers and focal adhesions in HSC-T6 cells transfected with CA-RhoA, but not in HSC-T6 transfected with DN-RhoA. Surprisingly, both CA- and DN-RhoA-transfected HSC-T6 cells showed decreased migratory potential in the absence or presence of PDGF-BB compared with controls.Conclusions PDGF-BB induced cytoskeletal remodeling in rat HSCs and promoted their migration via regulation of intracellular RhoA. RhoA may be one of

  3. Generation of lipid neutrophil chemoattractant by irradiated bovine aortic endothelial cells.

    Science.gov (United States)

    Matzner, Y; Cohn, M; Hyam, E; Razin, E; Fuks, Z; Buchanan, M R; Haas, T A; Vlodavsky, I; Eldor, A

    1988-04-15

    Radiation injury to blood vessels is associated with an acute inflammatory process. We investigated the capacity of cultured bovine aortic endothelial cells (BAEC) to produce chemotactic factors after radiation injury. BAEC in serum-free media were irradiated with a cobalt-60 Gammacell 220 and the cell supernatants were assayed for chemotactic activity for human neutrophils in a Boyden chamber. There was a rapid release of chemotactic activity into the BAEC supernatants which was dependent both on the dose of radiation (5 to 40 Gy) and the time between irradiation and sample collection. In contrast, isolation of BAEC lysates by freeze-thawing was not associated with the presence of similar chemotactic activity. The chemotactic activity released from the irradiated BAEC was not destroyed by boiling nor by treatment with trypsin. The release of the chemotactic activity was, however, inhibited by the addition of a lipoxygenase inhibitor but not by the addition of a cyclooxygenase inhibitor before the irradiation. The chemotactic activity was recovered from the cell supernatants in the lipid phase after extraction with chloroform/methanol. Furthermore, the chloroform/methanol extracts co-eluted with authentic leukotriene B4 when the BAEC were prelabeled with [14C] arachidonic acid. However, we were unable to detect endogenous leukotriene B4 with RIA. Instead, the only detectable endogenous lipid present in the supernatants was 13-hydroxyoctadecadienoic acid which is derived from linoleic acid via the lipoxygenase pathway. 13-Hydroxyoctadecadienoic acid, however, had no chemotactic activity. These findings suggest that endothelial cells rapidly release a chemotactic agent after irradiation, the release of which is associated with a lipoxygenase pathway. The release of this chemotactic activity may account in part for the acute inflammatory response that is observed after ionizing irradiation.

  4. Robust and Sparse Factor Modelling

    DEFF Research Database (Denmark)

    Croux, Christophe; Exterkate, Peter

    Factor construction methods are widely used to summarize a large panel of variables by means of a relatively small number of representative factors. We propose a novel factor construction procedure that enjoys the properties of robustness to outliers and of sparsity; that is, having relatively few...... nonzero factor loadings. Compared to the traditional factor construction method, we find that this procedure leads to a favorable forecasting performance in the presence of outliers and to better interpretable factors. We investigate the performance of the method in a Monte Carlo experiment and in an...

  5. Unity power factor converter

    Science.gov (United States)

    Wester, Gene W. (Inventor)

    1980-01-01

    A unity power factor converter capable of effecting either inversion (dc-to-dc) or rectification (ac-to-dc), and capable of providing bilateral power control from a DC source (or load) through an AC transmission line to a DC load (or source) for power flow in either direction, is comprised of comparators for comparing the AC current i with an AC signal i.sub.ref (or its phase inversion) derived from the AC ports to generate control signals to operate a switch control circuit for high speed switching to shape the AC current waveform to a sine waveform, and synchronize it in phase and frequency with the AC voltage at the AC ports, by selectively switching the connections to a series inductor as required to increase or decrease the current i.

  6. Psychosomatic factors in pruritus.

    Science.gov (United States)

    Tey, Hong Liang; Wallengren, Joanna; Yosipovitch, Gil

    2013-01-01

    Pruritus and psyche are intricately and reciprocally related, with psychophysiological evidence and psychopathological explanations helping us to understand their complex association. Their interaction may be conceptualized and classified into 3 groups: pruritic diseases with psychiatric sequelae, pruritic diseases aggravated by psychosocial factors, and psychiatric disorders causing pruritus. Management of chronic pruritus is directed at treating the underlying causes and adopting a multidisciplinary approach to address the dermatologic, somatosensory, cognitive, and emotional aspects. Pharmcotherapeutic agents that are useful for chronic pruritus with comorbid depression and/or anxiety comprise selective serotonin reuptake inhibitors, mirtazapine, tricyclic antidepressants (amitriptyline and doxepin), and anticonvulsants (gabapentin, pregabalin); the role of neurokinin receptor-1 antagonists awaits verification. Antipsychotics are required for treating itch and formication associated with schizophrenia and delusion of parasitosis (including Morgellons disease). PMID:23245971

  7. Nucleon Electromagnetic Form Factors

    Energy Technology Data Exchange (ETDEWEB)

    Marc Vanderhaeghen; Charles Perdrisat; Vina Punjabi

    2007-10-01

    There has been much activity in the measurement of the elastic electromagnetic proton and neutron form factors in the last decade, and the quality of the data has greatly improved by performing double polarization experiments, in comparison with previous unpolarized data. Here we review the experimental data base in view of the new results for the proton, and neutron, obtained at JLab, MAMI, and MIT-Bates. The rapid evolution of phenomenological models triggered by these high-precision experiments will be discussed, including the recent progress in the determination of the valence quark generalized parton distributions of the nucleon, as well as the steady rate of improvements made in the lattice QCD calculations.

  8. Pion form factor

    Energy Technology Data Exchange (ETDEWEB)

    Ryong Ji, C.; Pang, A.; Szczepaniak, A. [North Carolina State Univ., Raleigh, NC (United States)

    1994-04-01

    It is pointed out that the correct criterion to define the legal PQCD contribution to the exclusive processes in the lightcone perturbative expansion should be based on the large off-shellness of the lightcone energy in the intermediate states. In the lightcone perturbative QCD calculation of the pion form factor, the authors find that the legal PQCD contribution defined by the lightcone energy cut saturates in the smaller Q{sup 2} region compared to that defined by the gluon four-momentum square cut. This is due to the contribution by the highly off-energy-shell gluons in the end point regions of the phase space, indicating that the gluon four-momentum-square cut may have cut too much to define the legal PQCD.

  9. ADJUSTMENT FACTORS AND ADJUSTMENT STRUCTURE

    Institute of Scientific and Technical Information of China (English)

    Tao Benzao

    2003-01-01

    In this paper, adjustment factors J and R put forward by professor Zhou Jiangwen are introduced and the nature of the adjustment factors and their role in evaluating adjustment structure is discussed and proved.

  10. Critical factors for EIA implementation

    DEFF Research Database (Denmark)

    Zhang, Jasmine; Kørnøv, Lone; Christensen, Per

    2013-01-01

    After decades of development, the gap between expectations of Environment Impact Assessments (EIA) and their practical performance remains significant. Research has been done to identify the critical factors for an effective implementation of EIA. However, this research, to a large extent, has...... between different critical factors and how they relate to different stages in the EIA and thus influence the decision making process. After reviewing 33 refereed journal articles published between 1999 and 2011, we identified 203 notions of critical factors. Of these, 102 related to different stages...... defined in our comprehensive EIA implementation model, and 101 were identified as general factors related to the whole EIA system. The number of notions of stage factors and general factors is thus about equal. An overlap between stage factors and general factors was found, which demonstrates...

  11. R-Factor for Alaska

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The rainfall-runoff erosivity factor (R-Factor) quantifies the effects of raindrop impacts and reflects the amount and rate of runoff associated with the rain. The...

  12. Growth factors in tumor microenvironment

    OpenAIRE

    Zhang, Xuejing; Nie, Daotai; Chakrabarty, Subhas

    2010-01-01

    Tumor microenvironment plays a critical role in tumor initiation and progression. Components in the microenvironment can modulate the growth of tumor cells, their ability to progress and metastasize. A major venue of communication between tumor cells and their microenvironment is through polypeptide growth factors and receptors for these growth factors. This article discusses three major classes of growth-stimulatory polypeptide growth factors and receptors for these growth factors. It also d...

  13. Factorization invariants in numerical monoids

    OpenAIRE

    O'Neill, Christopher; Pelayo, Roberto

    2015-01-01

    Nonunique factorization in commutative monoids is often studied using factorization invariants, which assign to each monoid element a quantity determined by the factorization structure. For numerical monoids (co-finite, additive submonoids of the natural numbers), several factorization invariants have received much attention in the recent literature. In this survey article, we give an overview of the length set, elasticity, delta set, $\\omega$-primality, and catenary degree invariants in the ...

  14. Lithuanian Population Aging Factors Analysis

    OpenAIRE

    Agnė Garlauskaitė; Rasa Zabarauskaitė

    2015-01-01

    The aim of this article is to identify the factors that determine aging of Lithuania’s population and to assess the influence of these factors. The article shows Lithuanian population aging factors analysis, which consists of two main parts: the first describes the aging of the population and its characteristics in theoretical terms. Second part is dedicated to the assessment of trends that influence the aging population and demographic factors and also to analyse the determinants of the agin...

  15. Factor Price Equalization in Finland

    OpenAIRE

    Kerkelä, Leena; Kangasharju, Aki; Pekkala, Sari

    2003-01-01

    The Heckscher-Ohlin trade model leads to clear conclusions on the absolute and relative factor prices in a two-commodity specification of the model where both commodities are produced and factors can move freely within the economy. Even though the tests on factor price equalization fail in international comparisons, regional approach offers a prospective way of characterizing how factors of production, e.g. skilled and unskilled labor are utilized in optimally behaving markets and which poten...

  16. Stromal cell derived factor 1 effects on migration of endogenous neural stem cells%基质细胞衍生因子1对内源性神经干细胞的趋化迁移作用

    Institute of Scientific and Technical Information of China (English)

    苏稳; 丁鹏; 王进昆; 张浩; 牟临杰; 王波; 刘景传; 龚光辉; 王崇谦

    2014-01-01

    背景:目前研究表明,基质细胞衍生因子1在参与趋化迁移内源性神经干细胞中起着非常重要的作用,但其具体迁移机制尚不明确。  目的:观察外源性基质细胞衍生因子1对大鼠内源性神经干细胞的趋化迁移作用及海马区神经干细胞的激活增殖情况。  方法:通过向SD大鼠海马区上大脑皮质内注射外源性基质细胞衍生因子1(注射量为5μL,质量浓度为500μg/L)建立动物模型,于3,7,14,21 d后灌注取脑,通过石蜡切片免疫组织化学检测大鼠皮质内注射区及海马区nestin阳性细胞表达情况,并设实验对照组与空白对照组。  结果与结论:石蜡切片免疫组织化学显示:实验组注射区周围及海马区nestin表达阳性细胞的数量随时间推移逐渐增多,3,7 d时注射区及海马区nestin表达阳性细胞少量表达,14 d时注射区及海马区nestin表达阳性细胞进一步增多,并向注射区形成明显的迁移趋势,21 d时注射区及海马区nestin表达阳性细胞更多。实验对照组及空白实验组未见上述表现。结果表明外源性基质细胞衍生因子1可能诱导海马区神经干细胞的增殖分化,参与内源性神经干细胞的趋化迁移过程。%BACKGROUND:Stromal cellderived factor 1 in chemotactic migration of endogenous neural stem cells plays a very important role, but the specific migration mechanism is unclear OBJECTIVE:To observe the effects of exogenous stromal cellderived factor 1 on chemotactic migration and proliferation of neural stem cells in the rat hippocampus METHODS:Exogenous stromal cellderived factor 1 (5μL, 500μ/L) was injected into the hippocampus of Sprague-Dawley rats to establish animal models. Brain tissues were taken after days 3, 7, 14 and 21 of perfusion to prepare paraffin sections. Thereafter, nestin expression in the injection region and hippocampus was detected using immunohistochemical method

  17. Salivary Gland Cancer: Risk Factors

    Science.gov (United States)

    ... Factors Request Permissions Print to PDF Salivary Gland Cancer: Risk Factors Approved by the Cancer.Net Editorial Board , 08/ ... anything that increases a person’s chance of developing cancer. Although risk factors often influence the development of cancer, most do ...

  18. Risk Factor Assessment Branch (RFAB)

    Science.gov (United States)

    The Risk Factor Assessment Branch (RFAB) focuses on the development, evaluation, and dissemination of high-quality risk factor metrics, methods, tools, technologies, and resources for use across the cancer research continuum, and the assessment of cancer-related risk factors in the population.

  19. Investing in systematic factor premiums

    NARCIS (Netherlands)

    Koedijk, Kees G.; Slager, Alfred M. H.; Stork, P.A.

    2016-01-01

    In this paper we investigate and evaluate factor investing in the US and Europe for equities and bonds. We show that factor-based portfolios generally produce comparable or better portfolios than market indices. We expand the analysis to other asset classes and factors, work with other optimisation

  20. Risks factoring business: accounting measurement

    Directory of Open Access Journals (Sweden)

    Z.V. Gutsaylyuk

    2015-06-01

    Full Text Available The paper carried out the identification of risk factors for the development of possible accounting software management. Studied theoretical and methodological aspects of the risk classification of factoring operations in the part of the risk assessment factors. It is proposed to consider the risks factors as the risk that is acceptable controlled by accounting instruments and the risks that can not be taken into account in the accounting records. To minimize the risk factor, accounting-driven tools, a method of self-insurance, which is a factor in the creation of provision for factoring transactions designed to cover unexpected expenses and losses. Provision for factoring factor will establish more stable conditions of financial activity and avoid the fluctuations of profit factor in relation to the writing off of losses on factoring operatsіyam.Developed proposals allow for further research to improve the organizational and methodological basis of accounting and analysis of information as a basis for providing risk management factor, particularly in terms of improving the evaluation questions such risks and their qualitative and quantitative analysis.

  1. Factors Affecting Children Learning English

    Institute of Scientific and Technical Information of China (English)

    李楠

    2002-01-01

    By reviewing the literature, the author points out some theoretical defects of the CPH on which the policy was based. CPH is the conceptualization formulation of the maturational constraints for SLA. The paper, based on the reality of China, put forward some suggestion, which includes the time factor, the teacher's factor and the content factor.

  2. Human Factors in Training

    Science.gov (United States)

    Barshi, Immanuel; Byrne, Vicky; Arsintescu, Lucia; Connell, Erin

    2010-01-01

    Future space missions will be significantly longer than current shuttle missions and new systems will be more complex than current systems. Increasing communication delays between crews and Earth-based support means that astronauts need to be prepared to handle the unexpected on their own. As crews become more autonomous, their potential span of control and required expertise must grow to match their autonomy. It is not possible to train for every eventuality ahead of time on the ground, or to maintain trained skills across long intervals of disuse. To adequately prepare NASA personnel for these challenges, new training approaches, methodologies, and tools are required. This research project aims at developing these training capabilities. By researching established training principles, examining future needs, and by using current practices in space flight training as test beds, both in Flight Controller and Crew Medical domains, this research project is mitigating program risks and generating templates and requirements to meet future training needs. Training efforts in Fiscal Year 09 (FY09) strongly focused on crew medical training, but also began exploring how Space Flight Resource Management training for Mission Operations Directorate (MOD) Flight Controllers could be integrated with systems training for optimal Mission Control Center (MCC) operations. The Training Task addresses Program risks that lie at the intersection of the following three risks identified by the Project: 1) Risk associated with poor task design; 2) Risk of error due to inadequate information; and 3) Risk associated with reduced safety and efficiency due to poor human factors design.

  3. Factors of Project Manager Success

    Directory of Open Access Journals (Sweden)

    Raafat George Saadé

    2015-06-01

    Full Text Available This research seeks to analyse the project success factors related to project managers’ traits. The context of the research entails a ‘United Nations’ type of organization. Critical success factors from previous recent studies were adopted for this research. Nineteen factors were adopted and a survey methodology approach was followed. Sixty six participants completed the survey. Exploratory factor analysis results revealed the existence of two constructs: project manager engagement, and project manager certification. The total number of factors representing these two constructs after the factor reduction exercise is nine. Our findings indicate that the capacity for a project manager to communicate and lobby for the project to create and sustain positive perceptions, is the most important factor; whereas project manager credentials are viewed as not important for his/her success. The results may seem counter-intuitive, however, in the context of United Nations Organizations, consideration of their political, cultural and international nature reveals that the results apply.

  4. A factor analysis to detect factors influencing building national brand

    Directory of Open Access Journals (Sweden)

    Naser Azad

    Full Text Available Developing a national brand is one of the most important issues for development of a brand. In this study, we present factor analysis to detect the most important factors in building a national brand. The proposed study uses factor analysis to extract the most influencing factors and the sample size has been chosen from two major auto makers in Iran called Iran Khodro and Saipa. The questionnaire was designed in Likert scale and distributed among 235 experts. Cronbach alpha is calculated as 84%, which is well above the minimum desirable limit of 0.70. The implementation of factor analysis provides six factors including “cultural image of customers”, “exciting characteristics”, “competitive pricing strategies”, “perception image” and “previous perceptions”.

  5. Intravascular activation of complement and acute lung injury. Dependency on neutrophils and toxic oxygen metabolites.

    OpenAIRE

    Till, G O; Johnson, K J; R. Kunkel; Ward, P. A.

    1982-01-01

    Intravascular activation of the complement system with cobra venom factor results in acute lung injury, which has been quantitated by increases in lung vascular permeability. Cobra venom factor preparations devoid of phospholipase A2 activity retain full lung-damaging capacity. The lung injury is associated with the preceding appearance of chemotactic activity in the serum coincident with the development of a profound neutropenia. The chemotactic activity is immunochemically related to human ...

  6. Factor V Leiden and Inflammation

    OpenAIRE

    Silvia Perez-Pujol; Omer Aras; Gines Escolar

    2012-01-01

    Factor V Leiden, is a variant of human factor V (FV), also known as proaccelerin, which leads to a hypercoagulable state. Along these years, factor V Leiden (FVL) has been studied from the pathophysiologic point of view, and research has been focused on finding clinical approaches for the management of the FVL associated to a trombophilic state. Less attention has been paid about the possible role of FVL in inflammatory conditions known to be present in different disorders such as uremia, cir...

  7. Optimal Algorithm for Algebraic Factoring

    Institute of Scientific and Technical Information of China (English)

    支丽红

    1997-01-01

    This paper presents on optimized method for factoring multivariate polynomials over algebraic extension fields defined by an irreducible ascending set. The basic idea is to convert multivariate polynomials to univariate polynomials and algebraic extension fields to algebraic number fields by suitable integer substituteions.Then factorize the univariate polynomials over the algebraic number fields.Finally,construct mulativariate factors of the original polynomial by Hensel lemma and TRUEFACTOR test.Some examples with timing are included.

  8. Social networks and factor markets

    DEFF Research Database (Denmark)

    Abay, Kibrom Araya; Kahsay, Goytom Abraha; Berhane, Guush

    transactions among smallholder farmers. Using detailed longitudinal household survey data and employing a difference-in-differences approach, we find that iddir membership improves households’ access to factor markets. Specifically, we find that joining an iddir network improves households’ access to land......In the absence of well-established factor markets, the role of indigenous institutions and social networks can be substantial for mobilizing factors for agricultural production. We investigate the role of an indigenous social network in Ethiopia, the iddir, in facilitating factor market...

  9. Five Describing Factors of Dyslexia.

    Science.gov (United States)

    Tamboer, Peter; Vorst, Harrie C M; Oort, Frans J

    2016-09-01

    Two subtypes of dyslexia (phonological, visual) have been under debate in various studies. However, the number of symptoms of dyslexia described in the literature exceeds the number of subtypes, and underlying relations remain unclear. We investigated underlying cognitive features of dyslexia with exploratory and confirmatory factor analyses. A sample of 446 students (63 with dyslexia) completed a large test battery and a large questionnaire. Five factors were found in both the test battery and the questionnaire. These 10 factors loaded on 5 latent factors (spelling, phonology, short-term memory, rhyme/confusion, and whole-word processing/complexity), which explained 60% of total variance. Three analyses supported the validity of these factors. A confirmatory factor analysis fit with a solution of five factors (RMSEA = .03). Those with dyslexia differed from those without dyslexia on all factors. A combination of five factors provided reliable predictions of dyslexia and nondyslexia (accuracy >90%). We also looked for factorial deficits on an individual level to construct subtypes of dyslexia, but found varying profiles. We concluded that a multiple cognitive deficit model of dyslexia is supported, whereas the existence of subtypes remains unclear. We discussed the results in relation to advanced compensation strategies of students, measures of intelligence, and various correlations within groups of those with and without dyslexia. PMID:25398549

  10. First course in factor analysis

    CERN Document Server

    Comrey, Andrew L

    2013-01-01

    The goal of this book is to foster a basic understanding of factor analytic techniques so that readers can use them in their own research and critically evaluate their use by other researchers. Both the underlying theory and correct application are emphasized. The theory is presented through the mathematical basis of the most common factor analytic models and several methods used in factor analysis. On the application side, considerable attention is given to the extraction problem, the rotation problem, and the interpretation of factor analytic results. Hence, readers are given a background of

  11. Women's Career Success: A Factor Analytic Study of Contributing Factors.

    Science.gov (United States)

    Gaskill, LuAnn Ricketts

    1991-01-01

    A survey of 466 women employed in retailing received 205 responses identifying (1) factors influencing the success and advancement of women in retailing and (2) how those factors differ for women in upper versus middle positions. Upper-level executives placed more importance on ambition and abilities; midlevel executives credited opportunity and…

  12. Factorized molecular wave functions: Analysis of the nuclear factor

    Energy Technology Data Exchange (ETDEWEB)

    Lefebvre, R., E-mail: roland.lefebvre@u-psud.fr [Institut des Sciences Moléculaires d’ Orsay, Bâtiment 350, UMR8214, CNRS- Université. Paris-Sud, 91405 Orsay, France and Sorbonne Universités, UPMC Univ Paris 06, UFR925, F-75005 Paris (France)

    2015-06-07

    The exact factorization of molecular wave functions leads to nuclear factors which should be nodeless functions. We reconsider the case of vibrational perturbations in a diatomic species, a situation usually treated by combining Born-Oppenheimer products. It was shown [R. Lefebvre, J. Chem. Phys. 142, 074106 (2015)] that it is possible to derive, from the solutions of coupled equations, the form of the factorized function. By increasing artificially the interstate coupling in the usual approach, the adiabatic regime can be reached, whereby the wave function can be reduced to a single product. The nuclear factor of this product is determined by the lowest of the two potentials obtained by diagonalization of the potential matrix. By comparison with the nuclear wave function of the factorized scheme, it is shown that by a simple rectification, an agreement is obtained between the modified nodeless function and that of the adiabatic scheme.

  13. FACTORING- CREDIT OPPORTUNITIES IN ROMANIA

    Directory of Open Access Journals (Sweden)

    ADELA IONESCU

    2013-05-01

    Full Text Available Capital is the main factor of production, business development becomes virtually impossible without taking into account the financial market and the resources it provides to businesses. Any business, regardless of its degree of development, is involving direct contact with financial markets, namely the institutions that mediate mobilization of capital and the services they provide. Understanding the functioning of the financial system, the specific financial mechanisms through which savings are allocated to support capital investments and the costs and risks involved is essential for the development of a solid base for business. In this context, factoring operations can support economic agents, allowing a transfer of commercial receivables from their holder to a factor who commits to their recovery and guarantee such operations even if temporary or permanent insolvency of the debtor . Thus, factoring is a complex technique in at least two aspects, of the debt and the transfer of credit. . Factoring is a means of financing business, especially export-import transactions, less known in Romania. Maybe because of poor business environment popularize the term is as little known as it was a few years ago the leasing. Present in Romanian legislation since 2002, factoring appears as a contract between one party (called adherent, providing goods or service and a banking company or a financial institution specialized (called factor, which the last one shall finance debts pursuing and preservation against credit risks and adherent gives factor by way of sale, debts arising from the sale of goods or services to third parties. The article is divided into three parts. In the first part we defined the concept of factoring and international factoring, then I presented the advantages and development of factoring in Romania, and the last part conclusions.

  14. Matrix factorizations and elliptic fibrations

    Directory of Open Access Journals (Sweden)

    Harun Omer

    2016-09-01

    Full Text Available I use matrix factorizations to describe branes at simple singularities of elliptic fibrations. Each node of the corresponding Dynkin diagrams of the ADE-type singularities is associated with one indecomposable matrix factorization which can be deformed into one or more factorizations of lower rank. Branes with internal fluxes arise naturally as bound states of the indecomposable factorizations. Describing branes in such a way avoids the need to resolve singularities. This paper looks at gauge group breaking from E8 fibers down to SU(5 fibers due to the relevance of such fibrations for local F-theory GUT models. A purpose of this paper is to understand how the deformations of the singularity are understood in terms of its matrix factorizations. By systematically factorizing the elliptic fiber equation, this paper discusses geometries which are relevant for building semi-realistic local models. In the process it becomes evident that breaking patterns which are identical at the level of the Kodaira type of the fibers can be inequivalent at the level of matrix factorizations. Therefore the matrix factorization picture supplements information which the conventional less detailed descriptions lack.

  15. Factors associated with asthma control.

    NARCIS (Netherlands)

    Vries, M.P. de; Bemt, E.A.J.M. van den; Lince, S.; Muris, J.W.M.; Thoonen, B.P.A.; Schayck, C.P. van

    2005-01-01

    The aim of this study was to evaluate which factors are associated with asthma control experienced by asthma patients. In a cross-sectional study patients aged 16-60 years with mild to moderate asthma were selected. The influence of the following factors on asthma control was studied in a multivaria

  16. Prognostic Factors in Pancreatic Cancer

    OpenAIRE

    Åke Andrén-Sandberg

    2012-01-01

    Prognostic factors in pancreatic cancer have been a hot topic for the clinical pancreatology, and many studies have been involved in the field. The author reviewed the pancreatic abstracts of American Pancreas Club 2011, and sumarized "highlight" of all the abstracts in prognostic factors in pancreatic cancer.

  17. Risk Factors for Teenage Fatherhood.

    Science.gov (United States)

    Thornberry, Terence P.; Smith, Carolyn A.; Howard, Gregory J.

    1997-01-01

    Uses data from the Rochester Youth Development Study of urban youth (N=615) to identify early risk factors for the likelihood of becoming a teen father. Results show that teen fatherhood is related to a variety of risk factors, such as social class, educational performance, precocious sexual activity, and drug use. (RJM)

  18. Factorization with genus 2 curves

    OpenAIRE

    Cosset, Romain

    2009-01-01

    International audience The elliptic curve method (ECM) is one of the best factorization methods available. It is possible to use hyperelliptic curves instead of elliptic curves but it is in theory slower. We use special hyperelliptic curves and Kummer surfaces to reduce the complexity of the algorithm. Our implementation GMP-HECM is faster than GMP-ECM for factoring large numbers.

  19. Kadison-Kastler stable factors

    DEFF Research Database (Denmark)

    Cameron, Jan; Christensen, Erik; Sinclair, Allan M.;

    2014-01-01

    It is proven that a pair of continuous finite von Neumann algebra factors are unitarily equivalent if sufficiently close and one satisfies a certain cohomological condition.......It is proven that a pair of continuous finite von Neumann algebra factors are unitarily equivalent if sufficiently close and one satisfies a certain cohomological condition....

  20. Psychological Factors in English Study

    Institute of Scientific and Technical Information of China (English)

    吴西

    2015-01-01

    <正>1.Introduction The psychological factor that influences English study is dynamic,complex,and flexible.Its influence is not immediately known,but it rather accumulates over a period of time.It is inevitable that students have some psychological factors in learning English.Therefore,in the process of teaching,teachers

  1. Matrix factorizations and elliptic fibrations

    Science.gov (United States)

    Omer, Harun

    2016-09-01

    I use matrix factorizations to describe branes at simple singularities of elliptic fibrations. Each node of the corresponding Dynkin diagrams of the ADE-type singularities is associated with one indecomposable matrix factorization which can be deformed into one or more factorizations of lower rank. Branes with internal fluxes arise naturally as bound states of the indecomposable factorizations. Describing branes in such a way avoids the need to resolve singularities. This paper looks at gauge group breaking from E8 fibers down to SU (5) fibers due to the relevance of such fibrations for local F-theory GUT models. A purpose of this paper is to understand how the deformations of the singularity are understood in terms of its matrix factorizations. By systematically factorizing the elliptic fiber equation, this paper discusses geometries which are relevant for building semi-realistic local models. In the process it becomes evident that breaking patterns which are identical at the level of the Kodaira type of the fibers can be inequivalent at the level of matrix factorizations. Therefore the matrix factorization picture supplements information which the conventional less detailed descriptions lack.

  2. [Risk factors for arterial disease].

    Science.gov (United States)

    Madoery, Roberto; Rubin, Graciela; Luquez, Hugo; Luquez, Cecilia; Cravero, Cecilia

    2004-01-01

    The risk factors of arterial disease (FREA) predict a future damage over the vascular system of the human body. Its detection are considered a key for the diagnostic as well as for the preventive and even curative strategies. For a long time, scientist considered those factors originated as a consecuence of large studies during the middle of the last century, with current validity up to our days. A simple classification spoke of them as traditionals. Further investigations described the so called new or emergents.factors that where joint together accordingly to their actions: coagulation factors, psicosocial, inflamatories and infectious. A recent classification, taking into account the type of impact, divided them into; causatives, predisposals and conditionals. Also, it was described a mechanism, the oxidative power, with consecuences over the endothelium, in the last part of the process. Before, another mechanism was described: the insulin resistance and the hiperinsulinism, bases for the Metabolic Syndrome, that includes a number of traditional risk factors.

  3. Risk factors for suicidal behavior

    Directory of Open Access Journals (Sweden)

    Antonova A.A.

    2012-06-01

    Full Text Available

     

    The article presents data on risk factors that contribute to the development of suicidal behavior. The development of suicidal behavior is infuenced by a number of factors. These include — gender, age, residence, occupation, marital status, health status, etc. A number of studies indicated the impact of economic and social factors on the level of suicidal activity of the population. Observed relationship between mental disorders, substance abuse (particularly alcohol and suicide. In this case, the presence of numerous investigations in the feld of Suicidology, a number of problems still remains unsolved. Further study of issues relating to risk factors that infuence the development of suicidal behavior. Of particular note is the importance of “regional” risk factors that most infuence on the formation of suicidal behavior in a particular region.

  4. A New Factorization Method to Factorize RSA Public Key Encryption

    OpenAIRE

    Bhagvant Ram Ambedkar; Sarabjeet Singh Bedi

    2011-01-01

    The security of public key encryption such as RSA scheme relied on the integer factoring problem. The security of RSA algorithm is based on positive integer N, because each transmitting node generates pair of keys such as public and private. Encryption and decryption of any message depends on N. Where, N is the product of two prime numbers and pair of key generation is dependent on these prime numbers. The factorization of N is very intricate. In this paper a New Factorization method is propo...

  5. Analyze the relation between BMI and risk factors of obesity-related disease with multivariate linear regression in obese children%单纯性肥胖患儿BM I相关危险因素多元线性回归分析

    Institute of Scientific and Technical Information of China (English)

    王莉; 尹春燕; 肖延风; 薛晚利

    2013-01-01

    目的:研究单纯性肥胖患儿BM I相关危险因素,为预防肥胖相关疾病在儿童中的流行提供一定的指导。方法:对68例单纯性肥胖儿童测量身高、体重,留空腹血并检测血脂、肝功、血糖、胰岛素、C反应蛋白、单核细胞趋化因子、内脂素。结果:线性相关分析显示,BM I与C反应蛋白、单核细胞趋化因子、谷草转氨酶、甘油三酯、总胆固醇、高密度脂蛋白、低密度脂蛋白、胰岛素等具有简单线性相关;多元线性回归显示,甘油三酯、胰岛素、C反应蛋白、低密度脂蛋白与BM I密切相关。结论:甘油三酯、胰岛素、C反应蛋白、低密度脂蛋白与肥胖相关疾病密切相关,肥胖儿童通过降低其BM I水平,对于预防血脂紊乱、炎症性疾病及2型糖尿病的发生有重要意义。%Objective:To study the relation between BMI and risk factors of obesity-related disease and provide some guidance for preventing of obesity-related disease prevalence in children .Method:We recruited 68 obese children and the subjects’ body weight ,height were measured according to standardized techniques .Also lip-ids ,liver function ,blood glucose ,insulin ,C-reactive protein ,monocyte chemotactic factor ,visfatin were tested . Results :The linear correlation analysis showed that BMI had a simple linear correlation with C-reactive protein , monocyte chemotactic factor ,aspartate aminotransferase ,triglycerides ,total cholesterol ,high density lipoprotein , LDL and insulin ,we analysis with multivariate linear regression and it showed that triglycerides ,insulin ,C-reactive protein ,low-density lipoprotein were closely related with BMI .Conclusion :Triglycerides ,insulin ,C-reactive pro-tein and low-density lipoprotein are closely related to obesity-related diseases .It is important for obese children re-duce the level of BMI to prevent lipid disorders ,inflammatory diseases and type 2 diabetes .

  6. GATA factors in endocrine neoplasia.

    Science.gov (United States)

    Pihlajoki, Marjut; Färkkilä, Anniina; Soini, Tea; Heikinheimo, Markku; Wilson, David B

    2016-02-01

    GATA transcription factors are structurally-related zinc finger proteins that recognize the consensus DNA sequence WGATAA (the GATA motif), an essential cis-acting element in the promoters and enhancers of many genes. These transcription factors regulate cell fate specification and differentiation in a wide array of tissues. As demonstrated by genetic analyses of mice and humans, GATA factors play pivotal roles in the development, homeostasis, and function of several endocrine organs including the adrenal cortex, ovary, pancreas, parathyroid, pituitary, and testis. Additionally, GATA factors have been shown to be mutated, overexpressed, or underexpressed in a variety of endocrine tumors (e.g., adrenocortical neoplasms, parathyroid tumors, pituitary adenomas, and sex cord stromal tumors). Emerging evidence suggests that GATA factors play a direct role in the initiation, proliferation, or propagation of certain endocrine tumors via modulation of key developmental signaling pathways implicated in oncogenesis, such as the WNT/β-catenin and TGFβ pathways. Altered expression or function of GATA factors can also affect the metabolism, ploidy, and invasiveness of tumor cells. This article provides an overview of the role of GATA factors in endocrine neoplasms. Relevant animal models are highlighted.

  7. Ceramic materials and growth factors

    Energy Technology Data Exchange (ETDEWEB)

    Ohgushi, H.; Yoshikawa, T.; Okumura, M.; Nakajima, H.; Takakura, Y. [Nara Medical Univ. (Japan). Dept. of Orhtopaedic Surgery; Dohi, Y. [Nara Medical Univ. (Japan). Dept. of Public Health; Noshi, T.; Ikeuchi, M. [Nara Medical Univ. (Japan). Dept. of Oral and Maxillofacial Surgery

    2001-07-01

    Recently, many types of growth factors have been purified and used for promoting cell differentiation cascade. The activity of growth factors can be detected in vitro such as culture condition. However, the activity is difficult to detect when these factors are locally administered in vivo, because these dissipate soon after the administration. In order to retain growth factors in local milieu, these can be incorporated with biocompatible porous ceramic materials. Such ceramic/factors composites when implanted in vivo, can trigger certain types of cell differentiation cascade resulted in new tissue formation and tissue regeneration. The paper describes the ceramic / growth factors composites especially hydroxyapatite ceramic (HA) / bone morphogenetic protein (BMP) composite to induce osteoblastic differentiation of mesenchymal stem cells. The HA/BMP composite supported the osteoblastic differentiation on the HA surface and finally resulted in bone bonding to the HA. When the marrow mesenchymal stem cells (MSCs) were impregnated in pore areas of HA ceramics, the composites showed more and rapid bone formation than the HA/BMP and HA/MSCs composite, indicating the synergistic effect of BMP and MSCs. These findings indicate the importance of ceramic surface to evoke osteoblastic differentiation as well as to capture the molecules of growth factors for the cell differentiation. (orig.)

  8. What factors influence mitigative capacity?

    International Nuclear Information System (INIS)

    This article builds on Yohe's seminal piece on mitigative capacity, which elaborates 'determinants' of mitigative capacity, also reflected in the IPCC's third assessment report. We propose a revised definition, where mitigative capacity is a country's ability to reduce anthropogenic greenhouse gas emissions or enhance natural sinks. By 'ability' we mean skills, competencies, fitness, and proficiencies that a country has attained which can contribute to GHG emissions mitigation. A conceptual framework is proposed, linking mitigative capacity to a country's sustainable development path, and grouping the factors influencing mitigative capacity into three main sets: economic factors, institutional ones, and technology. Both quantitative and qualitative analysis of factors is presented, showing how these factors vary across countries. We suggest that it is the interplay between the three economic factors-income, abatement cost and opportunity cost-that shape mitigative capacity. We find that income is an important economic factor influencing mitigative capacity, while abatement cost is important in turning mitigative capacity into actual mitigation. Technology is a critical mitigative capacity, including the ability to absorb existing climate-friendly technologies or to develop innovative ones. Institutional factors that promote mitigative capacity include the effectiveness of government regulation, clear market rules, a skilled work force and public awareness. We briefly investigate such as high abatement cost or lack of political willingness that prevent mitigative capacity from being translated into mitigation

  9. Fano factor in rare gases

    International Nuclear Information System (INIS)

    Only few measurements have been made of the Fano factor in pure rare gases because of technical difficulties. Three methods are available for measuring the Fano factor: gridded ionization chamber method, proportional counter method and proportional scintillation method. Here, work is done to measure the Fano factor for 5.3 MeV alpha particles in He, He+Ar (1 %), Ar and Xe using a gridded ionization chamber technique developed by Kase. Results are presented and compared with other experimental and theoretical study results. The values of the factor measured are about 25 percent larger than theoretical and experimental values for electrons or X-rays incidence. These discrepancies are expected to be explained by the following two reasons. One is that the values obtained here may contain the nuclear elastic collision effect, which is not included in the theories. The other is that alpha particles produce many secondary electrons whose main component consists of slow electrons, and they increase the Fano factor because the factor becomes larger with decreasing incident electron energy. The contribution of nuclear elastic collisions may be clarified by comparing the values of Fano factor obtained in 3He and 4He. (N.K.)

  10. Environmental risk factors for autism

    Directory of Open Access Journals (Sweden)

    Rodney R. Dietert

    2011-04-01

    Full Text Available Autism is a devastating childhood condition that has emerged as an increasing social concern just as it has increased in prevalence in recent decades. Autism and the broader category of autism spectrum disorders are among the increasingly seen examples in which there is a fetal basis for later disease or disorder. Environmental, genetic, and epigenetic factors all play a role in determining the risk of autism and some of these effects appear to be transgenerational. Identification of the most critical windows of developmental vulnerability is paramount to understanding when and under what circumstances a child is at elevated risk for autism. No single environmental factor explains the increased prevalence of autism. While a handful of environmental risk factors have been suggested based on data from human studies and animal research, it is clear that many more, and perhaps the most significant risk factors, remain to be identified. The most promising risk factors identified to date fall within the categories of drugs, environmental chemicals, infectious agents, dietary factors, and other physical/psychological stressors. However, the rate at which environmental risk factors for autism have been identified via research and safety testing has not kept pace with the emerging health threat posed by this condition. For the way forward, it seems clear that additional focused research is needed. But more importantly, successful risk reduction strategies for autism will require more extensive and relevant developmental safety testing of drugs and chemicals.

  11. Corrosion effects on friction factors

    Energy Technology Data Exchange (ETDEWEB)

    Magleby, H.L.; Shaffer, S.J.

    1996-03-01

    This paper presents the results of NRC-sponsored material specimen tests that were performed to determine if corrosion increases the friction factors of sliding surfaces of motor-operated gate valves, which could require higher forces to close and open safety-related valves when subjected to their design basis differential pressures. Friction tests were performed with uncorroded specimens and specimens subjected to accelerated corrosion. Preliminary tests at ambient conditions showed that corrosion increased the friction factors, indicating the need for additional tests duplicating valve operating parameters at hot conditions. The additional tests showed friction factors of corroded specimens were 0.1 to 0.2 higher than for uncorroded specimens, and that the friction factors of the corroded specimens were not very dependent on contact stress or corrosion film thickness. The measured values of friction factors for the three corrosion films tested (simulating three operating times) were in the range of 0.3 to 0.4. The friction factor for even the shortest simulated operating time was essentially the same as the others, indicating that the friction factors appear to reach a plateau and that the plateau is reached quickly.

  12. Variation properties of ionospheric eclipse factor and ionospheric influence factor

    Institute of Scientific and Technical Information of China (English)

    ZHAO Chunmei; YUAN Yunbin; OU Jikun; CHEN Jinping

    2005-01-01

    The concepts and calculation methods of ionospheric eclipse factor (IEF) and ionospheric influence factor (IFF) are further illustrated. The temporal and spacial variation properties of IEF and IFF are studied, which shows that the properties are influenced by the geographic position and season. The possibility of improving the precision of using GPS data to determine ionospheric delay based on the above variation properties is also analysed.

  13. Dopamine receptor regulating factor, DRRF: A zinc finger transcription factor

    OpenAIRE

    Hwang, Cheol Kyu; D'Souza, Ursula M.; Eisch, Amelia J.; Yajima, Shunsuke; Lammers, Claas-Hinrich; Yang, Young; Lee, Sang-Hyeon; Kim, Yong-Man; Nestler, Eric J.; Mouradian, M. Maral

    2001-01-01

    Dopamine receptor genes are under complex transcription control, determining their unique regional distribution in the brain. We describe here a zinc finger type transcription factor, designated dopamine receptor regulating factor (DRRF), which binds to GC and GT boxes in the D1A and D2 dopamine receptor promoters and effectively displaces Sp1 and Sp3 from these sequences. Consequently, DRRF can modulate the activity of these dopamine receptor promoters. Highest DRRF mRNA levels are found in ...

  14. Genetics Home Reference: factor XIII deficiency

    Science.gov (United States)

    ... InfoSearch: Factor XIII deficiency Factor XIII Registry Database: Introduction to Factor XIII Deficiency MalaCards: factor xiii deficiency ... Library of Medicine Lister Hill National Center for Biomedical Communications 8600 Rockville Pike, Bethesda, MD 20894, USA ...

  15. On Factors Affecting Listening Comprehension

    Institute of Scientific and Technical Information of China (English)

    苗琴

    2014-01-01

    In English teaching and learning, listening ability is an important part of communicative competence, is a very practical integrated skill. It has been a difficult skill in second language acquisition for many students. Many Chinese students are skilled in reading, but often they tend to neglect the listening. However, owing to the higher requirements of many English tests and the great importance in communication, students begin to pay attention to develop their English listening skills. But there are many factors affecting listening, the paper mainly focuses on linguistic factors and non-linguistic factors that affect listening, to provide a theoretical basis to help exploring ways of improving listening and comprehension skills.

  16. Mode of action of staphylococcal leukocidin: effects of the S and F components on the activities of membrane-associated enzymes of rabbit polymorphonuclear leukocytes.

    OpenAIRE

    Noda, M; Kato, I.; Hirayama, T; Matsuda, F.

    1982-01-01

    The cytotoxic action of the S component of leukocidin from Staphylococcus aureus on rabbit polymorphonuclear leukocytes was supported by the following observations, (i) Leukocytes displayed a large chemotactic response to the S component (10(-10) M) as well as to the chemotactic factor N-formylmethionylleucylphenylalanine (10(-11) M). (ii) The S component stimulated high levels of phospholipase A2 activity in the cell membranes, with concomitant synthesis and release of prostaglandins. (iii) ...

  17. Human Factors Evaluation Mentor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — To obtain valid and reliable data, Human Factors Engineering (HFE) evaluations are currently conducted by people with specialized training and experience in HF. HFE...

  18. Matrix Factorization for Evolution Data

    Directory of Open Access Journals (Sweden)

    Xiao-Yu Huang

    2014-01-01

    Full Text Available We study a matrix factorization problem, that is, to find two factor matrices U and V such that R≈UT×V, where R is a matrix composed of the values of the objects O1,O2,…,On at consecutive time points T1,T2,…,Tt. We first present MAFED, a constrained optimization model for this problem, which straightforwardly performs factorization on R. Then based on the interplay of the data in U, V, and R, a probabilistic graphical model using the same optimization objects is constructed, in which structural dependencies of the data in these matrices are revealed. Finally, we present a fitting algorithm to solve the proposed MAFED model, which produces the desired factorization. Empirical studies on real-world datasets demonstrate that our approach outperforms the state-of-the-art comparison algorithms.

  19. Factorization Method in Quantum Mechanics

    CERN Document Server

    Dong, Shi-Hai

    2007-01-01

    This Work introduces the factorization method in quantum mechanics at an advanced level with an aim to put mathematical and physical concepts and techniques like the factorization method, Lie algebras, matrix elements and quantum control at the Reader’s disposal. For this purpose a comprehensive description is provided of the factorization method and its wide applications in quantum mechanics which complements the traditional coverage found in the existing quantum mechanics textbooks. Related to this classic method are the supersymmetric quantum mechanics, shape invariant potentials and group theoretical approaches. It is no exaggeration to say that this method has become the milestone of these approaches. In fact the Author’s driving force has been his desire to provide a comprehensive review volume that includes some new and significant results about the factorization method in quantum mechanics since the literature is inundated with scattered articles in this field, and to pave the Reader’s way into ...

  20. Success Factors of PLM Projects

    Institute of Scientific and Technical Information of China (English)

    谭月梅; 李莉敏; 胡庆夕; 方明伦

    2004-01-01

    Product Lifecycle Management (PLM) is a business strategy beginning to gain wide acceptance. Concerning the implementation of PLM projects, six success factors are presented and analyzed in details in this paper.

  1. Chemical Specific Adjustment Factors Workshop

    Science.gov (United States)

    The World Health Organization, through the International Programme on Chemical Safety (IPCS), has established guidance on the use of mechanistic data to replace default uncertainty factors for interspecies extrapolation and intraspecies variability in deriving risk values such as...

  2. Hidden Risk Factors for Women

    Science.gov (United States)

    ... high cholesterol. “Those are the most common risk factors,” according to Steven J. Kittner, M.D., director of the Maryland Stroke Center at the University of Maryland School of Medicine in Baltimore. “But ...

  3. Nucleocytoplasmic shuttling of transcription factors

    DEFF Research Database (Denmark)

    Cartwright, P; Helin, K

    2000-01-01

    To elicit the transcriptional response following intra- or extracellular stimuli, the signals need to be transmitted to their site of action within the nucleus. The nucleocytoplasmic shuttling of transcription factors is a mechanism mediating this process. The activation and inactivation...... of the transcriptional response is essential for cells to progress through the cell cycle in a normal manner. The involvement of cytoplasmic and nuclear accessory molecules, and the general nuclear membrane transport components, are essential for this process. Although nuclear import and export for different...... transcription factor families are regulated by similar mechanisms, there are several differences that allow for the specific activation of each transcription factor. This review discusses the general import and export pathways found to be common amongst many different transcription factors, and highlights...

  4. Microalbuminuria: a Cardiovascular Risk Factor

    OpenAIRE

    ERCAN, Ertuğrul

    2010-01-01

    Albumin is a protein which is charged negatively. By correcting for the daily excretion of creatinine, the albumin creatinin ratio implicates the daily excretion of albumin in spot urine. Albuminuria is a cardiovascular risk factor in patients with diabetes, hypertension, and the general population. Urinary albumin excretion is independently associated with an increased risk of cardiovascular events, even after adjustment for risk factors. Risk has been shown to increase continuously with inc...

  5. Improvements in quench factor modelling

    OpenAIRE

    Rometsch, P.A.; Starink, M.J.; Gregson, P.J.

    2003-01-01

    In this contribution, the validity of a number of key quench factor analysis (QFA) assumptions is discussed. It is shown that the incorporation of a square root dependency of yield strength on precipitate volume fraction provides a sounder physical basis for quench factor modelling. Peak-aged strength/hardness prediction accuracies are not affected, but C-curve positions are. It is also demonstrated that transformation kinetics are described more correctly by a modified Starink–Zahra equation...

  6. Environmental risk factors and pressures

    International Nuclear Information System (INIS)

    In this chapter the physical risk factors (as radiation [air contamination, contamination of the environment components and food contamination], radon and its radioactive decay products, radioactive wastes, noise), chemical risk factors [chemical substances, xenobiotics in the food chain the ozone depletion], wastes (waste generation, waste management, municipal waste management, import, export and transit of waste) and natural an technological hazards (water quality deterioration as a result of various accidents and fire risk) in the Slovak Republic in 1997 are reviewed

  7. View factors for surface zones

    OpenAIRE

    Koptelov, R. P.; Malikov, G. K.; Lisienko, V. G.

    2013-01-01

    Methods of calculating view factors with different surface configurations are compared. A simple approach is proposed for estimating the error in calculating the view factors. An algorithm is formulated for selection of the method and the number of points of integration prior to the calculation. The algorithm significantly reduces the computation time by minimizing the number of integration points required, without loss of precision. © 2013 Allerton Press, Inc.

  8. Erp Systems Critical Success Factors

    OpenAIRE

    Islam K. Sowan; Radwan Tahboub

    2015-01-01

    The Enterprise Resources Planning (ERP) systems are one of the highly complex systems in the information systems field; the implementations of this type of systems need a long time, high cost, and a lot of resources. Many factors affect the successful implementation of ERP system. The critical success factors (CSFs) can be categorized as general, ICT related and software engineering or system life cycle (SLC) related. This paper is a survey paper that identifies ERP systems CSFs in general an...

  9. Energy-absorbing effectiveness factor

    OpenAIRE

    Jones, Norman

    2010-01-01

    Abstract A study is reported on the energy-absorbing effectiveness factor which was introduced recently. The factor is defined as the quotient of the total energy, which can be absorbed in a system, to the maximum energy up to failure in a normal tensile specimen, which is made from the same volume of material. This dimensionless parameter allows comparisons to be made of the effectiveness of various geometrical shapes and of energy-absorbers made from different materials. The infl...

  10. Factors influencing dental decision making.

    Science.gov (United States)

    Grembowski, D; Milgrom, P; Fiset, L

    1988-01-01

    In clinical decision making, dentists routinely choose between alternative treatments such as crown vs amalgam/composite buildup, root canal vs extraction, fixed bridge vs removable partial denture, and prophylaxis vs subgingival curettage or periodontal scaling. A number of technical and patient factors can influence dentists' choice of treatment in these situations; however, little is known about their relative importance. To address this issue, a list of technical (e.g., periodontal status and caries rate) and patient (e.g., cost and patient preference) factors possibly influencing choice of treatment was developed for each pair of services. Responding to a mail questionnaire, 156 general dentists in Washington State listed the top three factors influencing their choice of service in each pair. Results revealed that dentists took different factors into account in choosing among alternative treatments. Technical factors dominated over patient concerns; only about 33 percent of the dentists considered patient factors important in choosing alternative therapies. The latter group was less preventively oriented, were solo practitioners, worked longer hours, and had lower prices. Results suggest patients may have little influence on prescriptions of therapy among experienced general dentists. PMID:3045303

  11. Growth factors and new periodontology

    Directory of Open Access Journals (Sweden)

    Paknejad M

    1999-06-01

    Full Text Available Growth factors are biological mediators that have a key roll in proliferation, chemotaxy and"ndifferentiation by acting on specific receptors on the surface of cells and regulating events in wound"nhealing.They can be considered hormones that are not released in to the blood stream but have one a"nlocal action. Some of these factors can regulate premature change in GO to Gl phase in cell devesion"ncycle and even may stimulate synthesis of DNA in suitable cells, Growth substances, primarily secreted"nby fibroblasts, endothelia! cells, macrophages and platelet, include platelet derived growth factor"n(PDGF, insulin like growth factor (IGF transforming growth factor (TGFa and (3 and bone"nmorphogenetic proteins BMPs that approximately are the most important of them. (BMPs could be"nused to control events during periodontal, craniofacial and implant wound healing through favoring bone"nformation"nAccording toLynch, combination of PGDF and IGF1 would be effective in promoting growth of all the"ncomponents of the periodontium."nThe aim of this study was to characterize growth factor and review the literature to determine the"nmechanism of their function, classification and application in implant and periodontal treatment.

  12. Universality of soft and collinear factors in hard scattering factorization

    CERN Document Server

    Collins, J C; Collins, John C.; Metz, Andreas

    2004-01-01

    Universality in QCD factorization of parton densities, fragmentation functions, and soft factors is endangered by the process dependence of the directions of Wilson lines in their definitions. We find a choice of directions that is consistent with factorization and that gives universality between e^+e^- annihilation, semi-inclusive deep-inelastic scattering, and Drell-Yan. Universality is only modified by a time-reversal transformation of the soft function and parton densities between Drell-Yan and the other processes, whose only effect is the known reversal of sign for T-odd parton densities like the Sivers function. The modifications of the definitions needed to remove rapidity divergences with light-like Wilson lines do not affect the results.

  13. Childhood asthma and risk factors

    Directory of Open Access Journals (Sweden)

    Ljuština-Pribić Radmila

    2010-01-01

    Full Text Available Introduction. This article summarizes the contribution of epidemiology to the understanding of childhood asthma. The first task in epidemiology is to determine prevalence and incidence of any disease. Prevalence. Epidemiological investigations are aimed at evaluating hypotheses about causes of disease by defining demographic characteristics of a certain population as well as by determining possible effects of environmental factors. In spite of some limitations, data obtained by epidemiological investigations have been valuable in confirming both the increasing incidence of asthma and the differences in prevalence in certain population groups. The observance of this phenomenon has led to much speculation and a lot of attempts to identify the reasons behind the rising prevalence. Risk factors. Epidemiological studies have identified risk factors for the development of childhood asthma and provided insight into natural history of disease and prognosis. Factors ranging from increased numbers of immunizations to increased air pollution have been suggested, but subsequent analysis has failed to provide the supporting evidence to implicate most of these possibilities. The concept known as the hygiene hypothesis has gained some support from epidemiological studies. Conclusion. The development of asthma as well as its severity are affected by numerous factors and their interactions can be explained by the heterogeneous nature of this disease.

  14. [Risk factors of necrotizing enterocolitis].

    Science.gov (United States)

    Tapia-Rombo, C A; Velasco-Lavín, M R; Nieto-Caldelas, A

    1993-09-01

    The purpose of the present study is to compare risk factors of necrotizing enterocolitis (NEC) between two group: group A, newborns with the disease and group B, newborns with other diseases different from NEC, in order to know if these risk factors are more frequent or not in the first group. We assessed the clinical records of all the patients hospitalized in the Neonatal Intensive Care Unit and Neonatology Service of the La Raza General Hospital between 1987 and 1991 with the diagnosis of NEC. They were compared with 65 clinical records chosen at random of patients hospitalized in the same Unit with other diagnosis at the same time, and who were discharged by improvement or deceased. In all of them were look for known risk factors for NEC generally accepted such as: prematurity, neonatal asphyxia, poliglobulia, cyanotic congenital heart disease, patent ductus arteriosus, respiratory distress syndrome, catheterization of umbilical vessels, early feeding of elevated formula increases, exchange exchange transfusion, hypoxic ischemic encephalopathy, infection, etc. Just 25 records of the possible 50 with the diagnosis of NEC full filled inclusion criteria. There were no statistically significant difference in weight, sex, mortality and known risk factors of NEC between both groups. Were concluded that NEC is a disease of unknown etiology that should be studied more thoroughly. The known risk factors must be avoided because the patient susceptibility probably play an important role. PMID:8373546

  15. Factors Influencing Healthcare Service Quality

    Directory of Open Access Journals (Sweden)

    Ali Mohammad Mosadeghrad

    2014-07-01

    Full Text Available Background The main purpose of this study was to identify factors that influence healthcare quality in the Iranian context. Methods Exploratory in-depth individual and focus group interviews were conducted with 222 healthcare stakeholders including healthcare providers, managers, policy-makers, and payers to identify factors affecting the quality of healthcare services provided in Iranian healthcare organisations. Results Quality in healthcare is a production of cooperation between the patient and the healthcare provider in a supportive environment. Personal factors of the provider and the patient, and factors pertaining to the healthcare organisation, healthcare system, and the broader environment affect healthcare service quality. Healthcare quality can be improved by supportive visionary leadership, proper planning, education and training, availability of resources, effective management of resources, employees and processes, and collaboration and cooperation among providers. Conclusion This article contributes to healthcare theory and practice by developing a conceptual framework that provides policy-makers and managers a practical understanding of factors that affect healthcare service quality.

  16. Geomorphological factors of flash floods

    Science.gov (United States)

    Kuznetsova, Yulia

    2016-04-01

    Growing anthropogenic load, rise of extreme meteorological events frequency and total precipitation depth often lead to increasing danger of catastrophic fluvial processes worldwide. Flash floods are one of the most dangerous and less understood types of them. Difficulties of their study are mainly related to short duration of single events, remoteness and hard access to origin areas. Most detailed researches of flash floods focus on hydrological parameters of the flow itself and its meteorological factors. At the same time, importance of the basin geological and geomorphological structure for flash floods generation and the role they play in global sediment redistribution is yet poorly understood. However, understanding and quantitative assessment of these features is a real basis for a complete concept of factors, characteristics and dynamics of flash floods. This work is a review of published data on flash floods, and focuses on the geomorphological factors of the phenomenon. We consider both individual roles and interactions between different geomorphological features (the whole basin parameters, characteristics of the single slopes and valley bottom). Special attention is paid to critical values of certain factors. This approach also highlights the gaps or less studied factors of flash floods. Finally, all data is organized into a complex diagram that may be used for flash floods modeling. This also may help to reach a new level of flash flood predictions and risk assessment.

  17. Effective Factors on CRM Development

    Directory of Open Access Journals (Sweden)

    Fakhraddin Maroofi

    2013-01-01

    Full Text Available The Customer Relationship Management (CRM literature is the value of po¬tential and current customers. In this research we investigate effective factors on CRM development which have direct or indirect relation with it. CRM is defined as an important key in business among companies to maintain and increase their customers. In this study we look for key factors like Organizing, Technology, Information technologies, Communication channels of interaction, Formation of CRM system and CRM strategies and some other general factors which indirectly affected the processes. The study analyses variants of CRM management system creation by reviewing different models of CRM creation, the analysis of which allowed envisaging typical elements of CRM model formation or stages of implementation process. Organizational excellence model of framework identify factors affecting productivity and the role of CRM systems. Successful CRM implementation is a complex, expensive and rarely technical projects. At the end of the study we introduce a model to the light of relationship between CRM and effective factors on it.

  18. Which shape factor(s) best describe granules?

    NARCIS (Netherlands)

    Bouwman, Anneke M.; Bosma, Jaap C.; Vonk, Pieter; Wesselingh, J.A.; Frijlink, Henderik W.

    2004-01-01

    This study evaluates methods used for granule shape characterization. The aim is to identify an optimal combination of shape factors to measure granule shape and roughness. Granules were prepared from microcrystalline cellulose (MCC), alpha-lactose, microfine cellulose (MFC), and dextrin, using a sm

  19. Success factors in technology development

    Science.gov (United States)

    Preston, John T.

    1995-01-01

    Universities in the U.S. have a significant impact on business through the transfer of technology. This paper describes goals and philosophy of the Technology Licensing Office at the Massachusetts Institute of Technology. This paper also relates the critical factors for susscessful technology transfer, particularly relating to new business formation. These critical factors include the quality of the technology, the quality of the management, the quality of the investor, the passion for success, and the image of the company. Descriptions of three different levels of investment are also given and the most successful level of investment for starting a new company is reviewed. Licensing to large companies is also briefly reviewed, as this type of licensing requires some different strategies than that of licensing to start-up companies. High quality critical factors and intelligent investment create rewards for the parties and successful ventures.

  20. Perinatal risk factors including malformation

    International Nuclear Information System (INIS)

    The study gives a survey of the factors most frequently mentioned in the literature as factors likely to adversely affect a pregnancy. One essential aspect is the discussion of those factors that can be counted among the causes of malformations, as among others, prenatal radiation exposure. The study prepared within the framework of the research project 'Radiobiological environmental monitoring in Bavaria' is intended to serve as a basis for a retrospective and prospective evaluation of infant mortality, perinatal conditions and occurrence of malformations in Bavaria, with the principal idea of drawing up an environment - related health survey. The study therefore, in addition to ionizing radiation also takes into account other detectable risks within the ecologic context, as e.g. industrial installations, refuse incineration plants or waste dumps, or urbanity. (orig./MG)

  1. Factor substitution in nursing homes.

    Science.gov (United States)

    Cawley, John; Grabowski, David C; Hirth, Richard A

    2006-03-01

    This paper studies factor substitution in one important sector: the nursing home industry. Specifically, we measure the extent to which nursing homes substitute materials for labor when labor becomes relatively more expensive. From a policy perspective, factor substitution in this market is important because materials-intensive methods of care are associated with greater risks of morbidity and mortality among nursing home residents. Studying longitudinal data from 1991 to 2000 on nearly every nursing home in the United States, we use the method of instrumental variables (IV) to address measurement error in nursing home wages. The results from the IV models yield evidence of factor substitution: higher nursing home wages are associated with greater use of psychoactive drugs and lower quality.

  2. Prognostic Factors in Hodgkin's Disease

    DEFF Research Database (Denmark)

    Specht

    1996-01-01

    Prognostic factors in Hodgkin's disease (HD) are reviewed. The Ann Arbor staging classification remains the basis for evaluation of patients with HD. However, subgroups of patients with differing prognoses exist within the individual stages. In pathological stages I and II, the number of involved...... regions and the tumor mass in each region are important, and an estimate of the total tumor burden has proved significant. B symptoms, histological subtype, age, and gender are also generally significant but less important. Prognostic factors for laparotomy findings in clinical stages I and II are: number...... of involved regions, disease confined to upper cervical nodes, B symptoms, gender, histology, age, and mediastinal disease (variable influence). In clinical stages I and II, the same prognostic factors apply as for pathological stages I and II and for laparotomy findings, and also some indirect...

  3. Prognostic Factors in Hodgkin's Disease

    DEFF Research Database (Denmark)

    Specht

    1996-01-01

    Prognostic factors in Hodgkin's disease (HD) are reviewed. The Ann Arbor staging classification remains the basis for evaluation of patients with HD. However, subgroups of patients with differing prognoses exist within the individual stages. In pathological stages I and II, the number of involved...... regions and the tumor mass in each region are important, and an estimate of the total tumor burden has proved significant. B symptoms, histological subtype, age, and gender are also generally significant but less important. Prognostic factors for laparotomy findings in clinical stages I and II are: number...... of involved regions, disease confined to upper cervical nodes, B symptoms, gender, histology, age, and mediastinal disease (variable influence). In clinical stages I and II, the same prognostic factors apply as for pathological stages I and II and for laparotomy findings, and also some indirect indicators...

  4. Stress factors in affective diseases.

    Science.gov (United States)

    Bidzińska, E J

    1984-02-01

    An investigation carried out on 97 patients with affective disorders and on 100 healthy control subjects, revealed that acute and chronic stress factors occurred more in the group of patients with affective disorders than among healthy control over a similar time period. The frequency of stressful life situations was the same before the first affective episode in patients with unipolar and bipolar illness. The possible participation of such factors in triggering the first phase of illness is discussed. Similar factors appeared in both types of affective disorders. Significantly more frequent among patients than in the control group were: marital and family conflicts, health problems, emotional and ambitional failures, lack of success and work overload.

  5. Boolean Factor Congruences and Property (*)

    CERN Document Server

    Terraf, Pedro Sánchez

    2008-01-01

    A variety V has Boolean factor congruences (BFC) if the set of factor congruences of every algebra in V is a distributive sublattice of its congruence lattice; this property holds in rings with unit and in every variety which has a semilattice operation. BFC has a prominent role in the study of uniqueness of direct product representations of algebras, since it is a strengthening of the refinement property. We provide an explicit Mal'cev condition for BFC. With the aid of this condition, it is shown that BFC is equivalent to a variant of the definability property (*), an open problem in R. Willard's work ("Varieties Having Boolean Factor Congruences," J. Algebra, 132 (1990)).

  6. Isospectral Potentials from Modified Factorization

    CERN Document Server

    Berger, Micheal S

    2010-01-01

    Factorization of quantum mechanical potentials has a long history extending back to the earliest days of the subject. In the present paper, the non-uniqueness of the factorization is exploited to derive new isospectral non-singular potentials. Many one-parameter families of potentials can be generated from known potentials using a factorization that involves superpotentials defined in terms of excited states of a potential. For these cases an operator representation is available. If ladder operators are known for the original potential, then a straightforward procedure exists for defining such operators for its isospectral partners. The generality of the method is illustrated with a number of examples which may have many possible applications in atomic and molecular physics.

  7. Isospectral potentials from modified factorization

    Science.gov (United States)

    Berger, Micheal S.; Ussembayev, Nail S.

    2010-08-01

    Factorization of quantum-mechanical potentials has a long history extending back to the earliest days of the subject. In the present article, the nonuniqueness of the factorization is exploited to derive new isospectral nonsingular potentials. Many one-parameter families of potentials can be generated from known potentials using a factorization that involves superpotentials defined in terms of excited states of a potential. For these cases an operator representation is available. If ladder operators are known for the original potential, then a straightforward procedure exists for defining such operators for its isospectral partners. The generality of the method is illustrated with a number of examples which may have many possible applications in atomic and molecular physics.

  8. Automatic summarising factors and directions

    CERN Document Server

    Jones, K S

    1998-01-01

    This position paper suggests that progress with automatic summarising demands a better research methodology and a carefully focussed research strategy. In order to develop effective procedures it is necessary to identify and respond to the context factors, i.e. input, purpose, and output factors, that bear on summarising and its evaluation. The paper analyses and illustrates these factors and their implications for evaluation. It then argues that this analysis, together with the state of the art and the intrinsic difficulty of summarising, imply a nearer-term strategy concentrating on shallow, but not surface, text analysis and on indicative summarising. This is illustrated with current work, from which a potentially productive research programme can be developed.

  9. Organizational Factors and Intrapreneurial Competences

    Directory of Open Access Journals (Sweden)

    Suzete Antonieta Lizote

    2013-12-01

    Full Text Available This study analyzes the relationship between organizational factors and entrepreneurial competencies of coordinators of undergraduate courses in two community universities in Santa Catarina, Brazil. The organizational factors studied were: management support, freedom at work, rewards, and time available and organizational limitations. Eight entrepreneurial competencies were considered; five included in an achievement set, and three in a planning set. The method was quantitative and descriptive, adopting a structured questionnaire as the data collection tool. Factor analysis, canonical analysis, and multiple regression analysis were performed. The results revealed a positive relationship between the constructs. The most relevant competencies were organizational limitations or uncertainty about tasks, and freedom at work, which indicates the importance having clarity about rules and decisions that should exist both at the level of performance expected of the coordinator, and the freedom that they must feel in their work.

  10. Factores medioambientales, vivienda y salud Environmental factors, housing and health

    Directory of Open Access Journals (Sweden)

    Ricardo Iglesias García

    2003-12-01

    Full Text Available Uno de los factores medioambientales más importantes que influyen en la salud de las personas es la vivienda, en la que pasamos dos tercios del día.En primer lugar, se realiza una revisión bibliográfica de los condicionantes de la vivienda que influyen sobre la salud. En segundo lugar, se analiza una serie de encuestas realizadas a residentes en bloques de viviendas, de varias ciudades europeas. Por último, se establecen los determinantes de la vivienda que influyen más en la salud y calidad de vida de sus residentes y que deben tenerse en cuenta en la renovación o modernización de las viviendas.A continuación se determinan los “factores ambientales de la vivienda que influyen potencialmente sobre la salud” y que deben ser reflejados en cualquier estudio sobre vivienda y salud. Por último se enumeran una serie de conclusiones y recomendaciones.One of the most important environmental factors affecting people is housing, since we live three quarters of our lives inside them.Firstly, a bibliographical revision about conditioning factors affecting health is made. Secondly, a series of questionnaires are analysed. They are addressed to apartment houses dwellers, in different European cities. Lastly, dwelling determinants which influence the most in health and quality of life, to be taken into account in the renovation or modernization of dwellings, are established.To end up, “environmental factors of dwellings potentially influencing health” and which must be taken into consideration in any study on housing and health, are determined. Finally, a series of conclusions and recommendations are made.

  11. Theoretical difference between impact factor and influence factor

    Directory of Open Access Journals (Sweden)

    Đilda Pečarić

    2010-06-01

    Full Text Available Bibliometric constructions of "knowledge maps" and "cognitive structures of science" do not differentiate between impact and influence factors. The difference can be constructedaccording to different meaning and interpretation of the terms reference and citation. Reference is "acknowledgment which one author gives to another", whereas citation is "acknowledgment which one document receives from another". Development of Information Science according to period and subject area is analyzed on the corpus of citation literature retrieved from doctoral dissertations in Information Science from 1978 to 2007 at Croatian universities. The research aim is to indicate the difference between document impact factor and author's influence factor (i.e. reference ability to produce effects on actions, behavior, and opinions of authors of doctoral theses. The influence factor serves to distinguish the key role of cited authors in time and according to the duration of the influence (the average age for cited papers of dominant authors in different periods is between eight and ten years. The difference between linear and interactive communication seems vital for the interpretation of cited half-life, i.e. the attitude of one science community towards used information resources and cognitive heritage. The analyzed corpus of 22,210 citations can be divided into three communication phases according to influence factor criteria: in the phase of dialogue and interactive communication 25% of bibliographic units are cited in the first four years; in the second phase another 25% of units are cited from the fifth to the ninth year; after ten years, in the dominant linear communication phase, approximately 30% of units are cited.

  12. Properties of Modal Quality Factors

    CERN Document Server

    Geyi, Wen

    2015-01-01

    Spherical wave functions play an important role in the theoretical study of antenna. When they are used to investigate the stored energy outside the circumscribing sphere of the antenna, two different types of modal quality factors appear which exhibit some interesting properties. These properties can be easily demonstrated by numerical tabulations but have never proved rigorously and have remained unsolved for many years. An attempt is made in this paper to try to solve these longstanding problems. New properties and new power series expansions for the modal quality factors have been obtained, which essentially belong to the spherical Bessel functions and therefore are universally applicable.

  13. Baryon Form Factors at Threshold

    Energy Technology Data Exchange (ETDEWEB)

    Baldini Ferroli, Rinaldo [Museo Storico della Fisica e Centro Studi e Ricerche ' E. Fermi' , Rome (Italy); INFN, Laboratori Nazionali di Frascati, Frascati (Italy); Pacetti, Simone [INFN and Dipartimento di Fisica, Universita di Perugia, Perugia (Italy)

    2012-04-15

    An extensive study of the e{sup +}e{sup -}{yields}pp{sup Macron }BABAR cross section data is presented. Two unexpected outcomes have been found: the modulus of the proton form factor is normalized to one at threshold, i.e.: |G{sup p}(4M{sub p}{sup 2})|=1, as a pointlike fermion, and the resummation factor in the Sommerfeld formula is not needed. Other e{sup +}e{sup -} {yields} baryon-antibaryon cross sections show a similar behavior near threshold.

  14. Unique Tensor Factorization of Algebras

    OpenAIRE

    Nüsken, Michael

    1998-01-01

    Tensor product decomposition of algebras is known to be non-unique in many cases. But, as will be shown here, an additively indecomposable, finite-dimensional C-algebra A has an essentially unique tensor factorization A=A1x...xAr into non-trivial, x-indecomposable factors Ai. Thus the semiring of isomorphism classes of finite-dimensional C-algebras is a polynomial semiring N[X]. Moreover, the field C of complex numbers can be replaced by an arbitrary field of characteristic zero if one restr...

  15. Fano factor in pure argon

    International Nuclear Information System (INIS)

    The Fano factor for 5.3 MeV alpha particles in pure argon has been measured with a gridded ionization chamber and estimated to be 0.20 (+0.01-0.02). The obtained value is consistent with the theoretical value if the contribution of elastic nuclear collisions to the Fano factor is taken into the consideration. There is no appreciable difference between the values for pure argon and for a gas mixture of Ar (10%)CH4 obtained in the previous measurement. (orig.)

  16. Age factors in biometric processing

    CERN Document Server

    Fairhurst, Michael

    2013-01-01

    As biometrics-based identification and identity authentication become increasingly widespread in their deployment, it becomes correspondingly important to consider more carefully issues relating to reliability, usability and inclusion. One factor which is particularly important in this context is that of the relationship between the nature of the measurements extracted from a particular biometric modality and the age of the sample donor, and the effect which age has on physiological and behavioural characteristics invoked in a biometric transaction. In Age Factors in Biometric Processing an in

  17. Factores de crecimiento III: factores transformadores del crecimiento (TGF Growth factors III part: transforming growth factors (TGF

    Directory of Open Access Journals (Sweden)

    Hilda Norha Jaramillo Londoño

    1996-04-01

    Full Text Available Se presenta una revisión de los conceptos básicos sobre los factores transformadores del crecimiento, tanto alfa como beta, incluyendo los siguientes aspectos: consideraciones generales, estructura bioquímica, concentraciones, proteínas transportadoras, receptores, mecanismos de acción y efectos biológicos. A review is presented on the basic concepts of Transforming Growth Factors both a and p; it includes general considerations, biochemical structure, concentrations, binding proteins, receptors, mechanisms of action, and biological effects.

  18. Factors associated with childhood obesity.

    Science.gov (United States)

    Dietz, W

    1991-01-01

    Childhood obesity is associated with host factors that enhance susceptibility and environmental factors that increase food intake and decrease energy expenditure. Obese children underreport food intake and probably consume more food to maintain their weight at increased levels. Prevalence of obesity is related to family variables, including parental obesity, family size and age, and socioeconomic status. Television viewing is strongly associated with the prevalence of obesity through its impact on food intake and activity. How these environmental variables are behaviorally interrelated to the genesis of obesity is unclear.

  19. 48 CFR 2015.304 - Evaluation factors.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Evaluation factors. 2015... Evaluation factors. The evaluation factors included in the solicitation serve as the standard against which... factors and subfactors by assigning a numerical weight to each factor. If a solicitation uses...

  20. Wave Packets can Factorize Numbers

    CERN Document Server

    Mack, H; Haug, F; Freyberger, M; Schleich, W P; Mack, Holger; Bienert, Marc; Haug, Florian; Freyberger, Matthias; Schleich, Wolfgang P.

    2002-01-01

    We draw attention to various aspects of number theory emerging in the time evolution of elementary quantum systems with quadratic phases. Such model systems can be realized in actual experiments. Our analysis paves the way to a new, promising and effective method to factorize numbers.

  1. Cardiovascular risk factors in men

    DEFF Research Database (Denmark)

    Gyllenborg, J; Rasmussen, S L; Borch-Johnsen, Knut;

    2001-01-01

    Males have higher risk of cardiovascular disease (CVD) than premenopausal females. Gonadal steroids are probably involved in the gender difference in CVD, but previous results have been conflicting. We investigated the associations between CVD risk factors and sex hormones in a cross...

  2. Seasonality of cardiovascular risk factors

    DEFF Research Database (Denmark)

    Marti-Soler, Helena; Gubelmann, Cédric; Aeschbacher, Stefanie;

    2014-01-01

    OBJECTIVE: To assess the seasonality of cardiovascular risk factors (CVRF) in a large set of population-based studies. METHODS: Cross-sectional data from 24 population-based studies from 15 countries, with a total sample size of 237 979 subjects. CVRFs included Body Mass Index (BMI) and waist...

  3. Simerka - Quadratic Forms and Factorization

    OpenAIRE

    Lemmermeyer, Franz

    2011-01-01

    In this article we show that the Czech mathematician Vaclav Simerka discovered the factorization of (10^17-1)/9 using a method based on the class group of binary quadratic forms more than 120 years before Shanks and Schnorr developed similar algorithms. Simerka also gave the first examples of what later became known as Carmichael numbers.

  4. Factors in Adolescent Rebellious Feelings.

    Science.gov (United States)

    Clemens, Patricia W.; Rust, James O.

    1979-01-01

    This study examined 15- and 16-year-old youths' (Midteens') feelings of anomie and rebellion in relation to family and situational factors. Only parents' formal education level and midteens' approval of the way they were being reared correlated significantly with midteens' scores on the Anomia and Rebellion Scales. (Author/SJL)

  5. Employability Development Teams: Cohesion Factors

    Science.gov (United States)

    Johnson, Douglas W.; Munger, Paul F.

    1972-01-01

    In this study the researchers attempted to analyze the factors of age, sex, racial-ethnic background, operational life of the team, educational status, leader status, team size, caseload size, and the location of program site in terms of their potential effects upon team cohesion. (Author)

  6. Risk factors for eating disorders

    Directory of Open Access Journals (Sweden)

    Monterrosa-Castro Álvaro

    2012-12-01

    Full Text Available Introduction: eating disorders (ED are characterized by the excessive worry aboutphysical appearance. They have high incidence in young population with more frequencyin women than in men.Objective: to identify the risk factors for ED.Methods: thematic review of publications in which are described and evaluated thedifferent risk factors to develop ED. It was done an electronic search since 1984 to2011, in english and spanish, in which were included all the methods of publications.There were reviewed the summaries to find the complete articles that treated about riskfactors associate with the development of the ED.Results: there were found 48203 about ED. 96 tried specifically about risk factors. 35(36.4% complete articles were obtained and the review was done with them.Conclusion: principal risk factors are: To be an adolescent, woman, to have distortedperception of the corporal image and the use of diet to lose weight. Rev.cienc.biomed.2012;3(2:300-305

  7. HUMAN PROSTATE CANCER RISK FACTORS

    Science.gov (United States)

    Prostate cancer has the highest prevalence of any non-skin cancer in the human body, with similar likelihood of neoplastic foci found within the prostates of men around the world regardless of diet, occupation, lifestyle, or other factors. Essentially all men with circulating an...

  8. Refined Factorizations of Solvable Potentials

    CERN Document Server

    Negro, J; Rosas-Ortiz, O

    2000-01-01

    A generalization of the factorization technique is shown to be a powerful algebraic tool to discover further properties of a class of integrable systems in Quantum Mechanics. The method is applied in the study of radial oscillator, Morse and Coulomb potentials to obtain a wide set of raising and lowering operators, and to show clearly the connection that link these systems.

  9. An innovation resistance factor model

    Directory of Open Access Journals (Sweden)

    Siti Salwa Mohd Ishak

    2016-09-01

    Full Text Available The process and implementation strategy of information technology in construction is generally considered through the limiting prism of theoretical contexts generated from innovation diffusion and acceptance. This research argues that more attention should be given to understanding the positive effects of resistance. The study develops a theoretical framing for the Integrated Resistance Factor Model (IRFM. The framing uses a combination of diffusion of innovation theory, technology acceptance model and social network perspective. The model is tested to identify the most significant resistance factors using Partial Least Square (PLS technique. All constructs proposed in the model are found to be significant, valid and consistent with the theoretical framework. IRFM is shown to be an effective and appropriate model of user resistance factors. The most critical factors to influence technology resistance in the online project information management system (OPIMS context are: support from leaders and peers, complexity of the technology, compatibility with key work practices; and pre-trial of the technology before it is actually deployed. The study provides a new model for further research in technology innovation specific to the construction industry.

  10. Environmental factors and semen quality

    DEFF Research Database (Denmark)

    Jurewicz, Joanna; Hanke, Wojciech; Radwan, Michal;

    2009-01-01

    , trihalomethanes (THMs), mobile phones) on semen quality, by reviewing most recent published literature. MATERIALS AND METHODS: Epidemiological studies focusing on exposure to environmental factors and semen quality for the last ten years were identified by a search of the Pubmed, Medline, Ebsco, Agricola...

  11. Decomposition using Maximum Autocorrelation Factors

    DEFF Research Database (Denmark)

    Larsen, Rasmus

    2002-01-01

    , normally we have an ordering of landmarks (variables) along the contour of the objects. For the case with observation ordering the maximum autocorrelation factor (MAF) transform was proposed for multivariate imagery in\\verb+~+\\$\\backslash\\$cite{switzer85}. This corresponds to a R-mode analyse of the data...

  12. Human factors in automotive innovation

    NARCIS (Netherlands)

    Terken, J.; Ham, J.; Hoedemaeker, M.

    2011-01-01

    Many automotive innovations affect the driver's task and/or the driving experience. In this paper we argue that successful innovation in these cases requires that due attention is given to Human Factors issues in the course of the innovation process. We support this claim by examples from several re

  13. Transcription factor-based biosensor

    Science.gov (United States)

    Dietrich, Jeffrey A; Keasling, Jay D

    2013-10-08

    The present invention provides for a system comprising a BmoR transcription factor, a .sigma..sup.54-RNA polymerase, and a pBMO promoter operatively linked to a reporter gene, wherein the pBMO promoter is capable of expression of the reporter gene with an activated form of the BmoR and the .sigma..sup.54-RNA polymerase.

  14. Temporal factors in resource dilemmas

    NARCIS (Netherlands)

    Hendrickx, L; Poortinga, W; van der Kooij, R

    2001-01-01

    The conflict between present and future consumption lies at the heart of resource dilemmas (RDs), yet the role of time has received little attention in this research area. Emphasis was on factors related to the social rather than the temporal conflict inherent in an RD. We propose a model that deals

  15. Nutritional factors in human cancers.

    Science.gov (United States)

    Giovannucci, E

    1999-01-01

    A variety of external factors interacting with genetic susceptibility influence the carcinogenesis process. External factors including oxidative compounds, electrophilic agents, and chronic infections may enhance genetic damage. In addition, various hormonal factors which influence growth and differentiation are critically important in the carcinogenic process. Diet and nutrition can influence these processes directly in the gastrointestinal tract by providing bioactive compounds to specific tissues via the circulatory system, or by modulating hormone levels. Differences in certain dietary patterns among populations explain a substantial proportion of cancers of the colon, prostate and breast. These malignancies are largely influenced by a combination of factors related to diet and nutrition. Their causes are multifactorial and complex, but a major influence is the widespread availability of energy-dense, highly processed and refined foods that are also deplete in fiber. These dietary patterns in combination with physical inactivity contribute to obesity and metabolic consequences such as increased levels of IGF-1, insulin, estrogen, and possibly testosterone. These hormones tend to promote cellular growth. For prostate cancer, epidemiologic studies consistently show a positive association with high consumption of milk, dairy products, and meats. These dietary factors tend to decrease 1.25(OH)2 vitamin D, a cell differentiator, and low levels of this hormone may enhance prostate carcinogenesis. While the nutritional modulation of growth-enhancing and differentiating hormones is likely to contribute to the high prevalence of breast, colorectal, prostate, and several other cancers in the Western world, these cancers are relatively rare in less economically developed countries, where malignancies of the upper gastrointestinal tract are quite common. The major causes of upper gastrointestinal tract cancers are likely related to various food practices or preservation

  16. CEREBRAL PALSY : ANTENATAL RISK FACTORS

    Directory of Open Access Journals (Sweden)

    Srinivasa Rao

    2015-05-01

    Full Text Available INTRODUCTION: Cerebral palsy (CP is a group of permanent movement disorders that appear in early childhood. Cerebral palsy is caused by abnormal development or damage to the parts of the brain that control movement, balance, and posture. Most often the problems occur during pregnancy; however, they may also occur during childbirth, or shortly after birth. Often the cause is unknown. AIM: To study the different antenatal maternal risk factors associated with cerebral palsy in the study group. MATERIA LS AND METHODS: Retrospective study was done to assess possible associated antenatal risk factors for cerebral palsy. Mothers of 100 cerebral palsy children were selected who are treated in Rani Chandramani Devi Hospital, a Government hospital in Visakhapa tn am, Andhra Pradesh State, India , from 2012 to 2014 and 100 controls, mothers of normal children were studied. Detailed antenatal history was obtained from the mothers of the children in both affected and control group. RESULTS: From the data, we conclude that the association of maternal anaemia with cerebral palsy is 7.3 times higher; association of maternal hypertension with cerebral palsy is 6.6 time higher, association with Pre - eclampsia is 6 times higher; association with Eclampsia is 8.6 times higher ; with antepartum haemorrhage, the association is 8.6 times higher and association of multiple pregnancy with cerebral palsy is 4.8 times higher than with controls. CONCLUSION: From this study of the role of antenatal risk factors, in the occurrence of cer ebral palsy in children it is concluded that the most common risk factor associated with cerebral palsy is the maternal anaemia and the other important risk factors associated being hypertension, pre eclampsia, eclampsia, antepartum haemorrhage and multipl e births.

  17. Prognostic factors in prostate cancer.

    Science.gov (United States)

    Braeckman, Johan; Michielsen, Dirk

    2007-01-01

    In the nineteenth century the main goal of medicine was predictive: diagnose the disease and achieve a satisfying prognosis of the patient's chances. Today the effort has shifted to cure the disease. Since the twentieth century, the word prognosis has also been used in nonmedical contexts, for example in corporate finance or elections. The most accurate form of prognosis is achieved statistically. Based on different prognostic factors it should be possible to tell patients how they are expected to do after prostate cancer has been diagnosed and how different treatments may change this outcome. A prognosis is a prediction. The word prognosis comes from the Greek word (see text) and means foreknowing. In the nineteenth century this was the main goal of medicine: diagnose the disease and achieve a satisfying prognosis of the patient's chances. Today the effort has shifted towards seeking a cure. Prognostic factors in (prostate) cancer are defined as "variables that can account for some of the heterogeneity associated with the expected course and outcome of a disease". Bailey defined prognosis as "a reasoned forecast concerning the course, pattern, progression, duration, and end of the disease. Prognostic factors are not only essential to understand the natural history and the course of the disease, but also to predict possible different outcomes of different treatments or perhaps no treatment at all. This is extremely important in a disease like prostate cancer where there is clear evidence that a substantial number of cases discovered by prostate-specific antigen (PSA) testing are unlikely ever to become clinically significant, not to mention mortal. Furthermore, prognostic factors are of paramount importance for correct interpretation of clinical trials and for the construction of future trials. Finally, according to WHO national screening committee criteria for implementing a national screening programme, widely accepted prognostic factors must be defined before

  18. What Are Coronary Heart Disease Risk Factors?

    Science.gov (United States)

    ... from the NHLBI on Twitter. What Are Coronary Heart Disease Risk Factors? Coronary heart disease risk factors are ... high blood pressure, overweight and obesity, and others. Heart Disease Risk Factors 09/30/2011 This video—presented ...

  19. Genetics Home Reference: factor V deficiency

    Science.gov (United States)

    ... Genetics Home Health Conditions factor V deficiency factor V deficiency Enable Javascript to view the expand/collapse ... Print All Open All Close All Description Factor V deficiency is a rare bleeding disorder. The signs ...

  20. Activated human neutrophils release hepatocyte growth factor/scatter factor.

    LENUS (Irish Health Repository)

    McCourt, M

    2012-02-03

    BACKGROUND: Hepatocyte growth factor or scatter factor (HGF\\/SF) is a pleiotropic cytokine that has potent angiogenic properties. We have previously demonstrated that neutrophils (PMN) are directly angiogenic by releasing vascular endothelial growth factor (VEGF). We hypothesized that the acute inflammatory response can stimulate PMN to release HGF. AIMS: To examine the effects of inflammatory mediators on PMN HGF release and the effect of recombinant human HGF (rhHGF) on PMN adhesion receptor expression and PMN VEGF release. METHODS: In the first experiment, PMN were isolated from healthy volunteers and stimulated with tumour necrosis factor-alpha (TNF-alpha), lipopolysaccharide (LPS), interleukin-8 (IL-8), and formyl methionyl-leucyl-phenylalanine (fMLP). Culture supernatants were assayed for HGF using ELISA. In the second experiment, PMN were lysed to measure total HGF release and HGF expression in the PMN was detected by Western immunoblotting. Finally, PMN were stimulated with rhHGF. PMN CD 11a, CD 11b, and CD 18 receptor expression and VEGF release was measured using flow cytometry and ELISA respectively. RESULTS: TNF-alpha, LPS and fMLP stimulation resulted in significantly increased release of PMN HGF (755+\\/-216, 484+\\/-221 and 565+\\/-278 pg\\/ml, respectively) compared to controls (118+\\/-42 pg\\/ml). IL-8 had no effect. Total HGF release following cell lysis and Western blot suggests that HGF is released from intracellular stores. Recombinant human HGF did not alter PMN adhesion receptor expression and had no effect on PMN VEGF release. CONCLUSIONS: This study demonstrates that pro-inflammatory mediators can stimulate HGF release from a PMN intracellular store and that activated PMN in addition to secreting VEGF have further angiogenic potential by releasing HGF.

  1. Eigenstates of coupling factor and loss factor of piezoelectric ceramics

    International Nuclear Information System (INIS)

    A short history of piezoelectricity is given and its occurence in nature described. The physical background of piezoelectric loss is discussed together with how material coefficients like susceptibilities can be used to describe the relation between canonical variables and to determine the dissipation of energy. The piezoelectric coupling factor, the applications of the eigencoupling state, elastic and piezoelectric digenstates are dealt with. The composition of the measurement system is described and experimental values of ceramics given. (C.F.)

  2. Weak factor automata: the failure of failure factor oracles?

    Directory of Open Access Journals (Sweden)

    Loek Cleophas

    2014-08-01

    Full Text Available In indexing of, and pattern matching on, DNA and text sequences, it is often important to represent all factors of a sequence. One efficient, compact representation is the factor oracle (FO. At the same time, any classical deterministic finite automata (DFA can be transformed to a so-called failure one (FDFA, which may use failure transitions to replace multiple symbol transitions, potentially yielding a more compact representation. We combine the two ideas and directly construct a failure factor oracle (FFO from a given sequence, in contrast to ex post facto transformation to an FDFA. The algorithm is suitable for both short and long sequences. We empirically compared the resulting FFOs and FOs on number of transitions for many DNA sequences of lengths 4 − 512, showing gains of up to 10% in total number of transitions, with failure transitions also taking up less space than symbol transitions. The resulting FFOs can be used for indexing, as well as in a variant of the FO-using backward oracle matching algorithm. We discuss and classify this pattern matching algorithm in terms of the keyword pattern matching taxonomies of Watson, Cleophas and Zwaan. We also empirically compared the use of FOs and FFOs in such backward reading pattern matching algorithms, using both DNA and natural language (English data sets. The results indicate that the decrease in pattern matching performance of an algorithm using an FFO instead of an FO may outweigh the gain in representation space by using an FFO instead of an FO.

  3. Automatic Power Factor Correction Using Capacitive Bank

    OpenAIRE

    Mr.Anant Kumar Tiwari,; Mrs. Durga Sharma

    2014-01-01

    The power factor correction of electrical loads is a problem common to all industrial companies. Earlier the power factor correction was done by adjusting the capacitive bank manually [1]. The automated power factor corrector (APFC) using capacitive load bank is helpful in providing the power factor correction. Proposed automated project involves measuring the power factor value from the load using microcontroller. The design of this auto-adjustable power factor correction is ...

  4. On the factorization of RSA-120

    OpenAIRE

    Denny, T; Dodson, B.; Lenstra, Arjen K.; Manasse, M. S.

    1994-01-01

    We present data concerning the factorization of the 120-digit number RSA-120, which we factored on July 9, 1993, using the quadratic sieve method. The factorization took approximately 825 MIPS years and was completed within three months real time. At the time of writing RSA-120 is the largest integer ever factored by a general purpose factoring algorithm. We also present some conservative extrapolations to estimate the difficulty of factoring even larger numbers, using either the quadratic si...

  5. The Infinite Hierarchical Factor Regression Model

    CERN Document Server

    Rai, Piyush

    2009-01-01

    We propose a nonparametric Bayesian factor regression model that accounts for uncertainty in the number of factors, and the relationship between factors. To accomplish this, we propose a sparse variant of the Indian Buffet Process and couple this with a hierarchical model over factors, based on Kingman's coalescent. We apply this model to two problems (factor analysis and factor regression) in gene-expression data analysis.

  6. Growth factors: first part Factores de crecimiento I

    Directory of Open Access Journals (Sweden)

    Hilda Norha Jaramillo Londoño

    1996-02-01

    Full Text Available

    Los factores de crecimiento tienen como función activar o inhibir la transcripción génica; es así como la cascada enzimática que se inicia con la activación de los receptores de la membrana citoplasmática, ya sean de tipo segundo mensajero o catalíticos, tiene como efecto final la fosforilación de proteínas, las cuales pueden ser: 1 enzimas que intervienen en las vías metabólicas; 2 proteínas promotoras de la transcripción de genes o, por el contrario, represoras de los mismos (31,32; en algunos casos el efecto final consiste en la transcripción de protooncogenes (33 cuyos productos pueden ser otro factor de crecimiento o receptores para éstos (16; 3 algunos factores de crecimiento ejercen sus efectos sobre los eventos postranscripcionales y postraslacionales (23.

    Los Factores de Crecimiento, incluyendo las citoquinas, representan un número muy grande de polipéptidos, glucoproteínas y otras moléculas relacionadas. Todos ellos promueven la proliferación, la diferenciación y las funciones especializadas de casi cualquier tipo de célula. Juegan un papel importante mediando los modos paracrino, autocrino y endocrino de comunicación. En esta primera parte de una serie se definen y clasifican los factores de crecimiento; para la clasificación se proponen diversos sistemas basados en el período de desarrollo del individuo en que actúan, en el punto crítico del ciclo celular sobre el que ejercen su acción y en los efectos fisiológicos que producen; se discuten, además, someramente, la composición química, los mecanismos de acción y las funciones de estas sustancias.

  7. Psychological Factors in Essential Hypertension

    Directory of Open Access Journals (Sweden)

    Barbaros Özdemir

    2010-04-01

    Full Text Available Essential hypertension is one of the most emphasized psychosomatic disorders. Age, sexuality, excessive salt and alcohol consumption, lower activity level, fatigue, personality traits, emotional factors and stress are some of the risk factors for essential hypertension. The presence of emotional factors in the etiology of the essential hypertension and the emergence of psychiatric symptoms in the course of the illness has driven considerable attention from mental health workers on the disease for a long time. Some of the personality traits that make a person vulnerable to hypertension are being over controlled, being submissive, and hardworking. Hypertension is accepted to be a reaction against suppressed emotions and an adaptive and defense mechanism of the body. Among persons who are prone to hypertension, sympathetic nerve system is affected as a response to emotional stress and hypertension appears as a result of vasoconstriction and other autonomous responses. All at once, it was also shown that vasoconstrictor response continues much longer in hypertensive individuals than in normotensive patients. Autonomic response to stress almost always displays itself as hypertension in individuals who are prone to hypertension. Moreover, normotensive children of hypertensive parents also have elevation in blood pressures as a response to emotional stress almost without exception. The increase in sympathetic stimulus, re-modulation of bar receptors by structural and functional changes are the main features of the most commonly valid hypothesis in essential hypertension, currently. According to this hypothesis: as a result of emotional stress, inhibition over vasomotor center decreases and output of stimulus increases; epigenetic changes in endothelial structure of carotid sinus and/or aortic arch and/or vasomotor centers occurs; and finally stress increases sympathetic stimulus output. This situation leads to neurohormonal excitation; increases in

  8. Human Factors and Medical Devices

    International Nuclear Information System (INIS)

    Medical device hardware- and software-driven user interfaces should be designed to minimize the likelihood of use-related errors and their consequences. The role of design-induced errors in medical device incidents is attracting widespread attention. The U.S. Food and Drug Administration (FDA) is fully cognizant that human factors engineering is critical to the design of safe medical devices, and user interface design is receiving substantial attention by the agency. Companies are paying more attention to the impact of device design, including user instructions, upon the performance of those health professionals and lay users who operate medical devices. Concurrently, the FDA is monitoring human factors issues in its site inspections, premarket device approvals, and postmarket incident evaluations. Overall, the outlook for improved designs and safer device operation is bright

  9. Nutritional Factors Affecting Mental Health

    Science.gov (United States)

    Lim, So Young; Kim, Eun Jin; Kim, Arang; Lee, Hee Jae; Choi, Hyun Jin

    2016-01-01

    Dietary intake and nutritional status of individuals are important factors affecting mental health and the development of psychiatric disorders. Majority of scientific evidence relating to mental health focuses on depression, cognitive function, and dementia, and limited evidence is available about other psychiatric disorders including schizophrenia. As life span of human being is increasing, the more the prevalence of mental disorders is, the more attention rises. Lists of suggested nutritional components that may be beneficial for mental health are omega-3 fatty acids, phospholipids, cholesterol, niacin, folate, vitamin B6, and vitamin B12. Saturated fat and simple sugar are considered detrimental to cognitive function. Evidence on the effect of cholesterol is conflicting; however, in general, blood cholesterol levels are negatively associated with the risk of depression. Collectively, the aims of this review are to introduce known nutritional factors for mental health, and to discuss recent issues of the nutritional impact on cognitive function and healthy brain aging.

  10. Factorization of chiral string amplitudes

    Science.gov (United States)

    Huang, Yu-tin; Siegel, Warren; Yuan, Ellis Ye

    2016-09-01

    We re-examine a closed-string model defined by altering the boundary conditions for one handedness of two-dimensional propagators in otherwise-standard string theory. We evaluate the amplitudes using Kawai-Lewellen-Tye factorization into open-string amplitudes. The only modification to standard string theory is effectively that the spacetime Minkowski metric changes overall sign in one open-string factor. This cancels all but a finite number of states: as found in earlier approaches, with enough supersymmetry (e.g., type II) the tree amplitudes reproduce those of the massless truncation of ordinary string theory. However, we now find for the other cases that additional fields, formerly thought to be auxiliary, describe new spin-2 states at the two adjacent mass levels (tachyonic and tardyonic). The tachyon is always a ghost, but can be avoided in the heterotic case.

  11. Factorization of Chiral String Amplitudes

    CERN Document Server

    Huang, Yu-tin; Yuan, Ellis Ye

    2016-01-01

    We re-examine a closed-string model defined by altering the boundary conditions for one handedness of two-dimensional propagators in otherwise-standard string theory. We evaluate the amplitudes using Kawai-Lewellen-Tye factorization into open-string amplitudes. The only modification to standard string theory is effectively that the spacetime Minkowski metric changes overall sign in one open-string factor. This cancels all but a finite number of states: As found in earlier approaches, with enough supersymmetry (e.g., type II) the tree amplitudes reproduce those of the massless truncation of ordinary string theory. However, we now find for the other cases that additional fields, formerly thought to be auxiliary, describe new spin-2 states at the two adjacent mass levels (tachyonic and tardyonic). The tachyon is always a ghost, but can be avoided in the heterotic case.

  12. PROGNOSTIC FACTORS IN CERVICAL CARCINOMA

    Institute of Scientific and Technical Information of China (English)

    路平; 梁秋冬; 魏磊; 郑全庆

    2002-01-01

    Objective: To evaluate factors for prognosis of cervical carcinoma. Methods: Expressions of mn23- HI, erbB3 and erbB4 were examined by immunohistochemical staining. The apoptosis was detected in situ by the TdT mediated duip-biotin nick end-labeling (TUNEL) technique. Mitotic cell were counted by HE dyeing. Results: FIGO stage and lymph node metastasis were the most important factors for evaluating prognosis in adenocarcinoma or squamous cell carcinoma. AI/MI was positively correlated with 5-year survival of cervical carcinoma. Positive expression of nm23-H1 combed with negative expression of erbB4 [nm23-H1(+)/erbB4(-)] predicted good prognosis for adeno-carcinoma. In multivariable Cox regression analysis, only FIGO stage and AI/MI were into equation. Conclusion: FIGO stage and AI/MI were independent evaluating parameter for adenocarcinoma or squamous cell carcinoma.

  13. On factorization of molecular wavefunctions

    International Nuclear Information System (INIS)

    Recently there has been a renewed interest in the chemical physics literature of factorization of the position representation eigenfunctions {Φ} of the molecular Schrödinger equation as originally proposed by Hunter in the 1970s. The idea is to represent Φ in the form φχ where χ is purely a function of the nuclear coordinates, while φ must depend on both electron and nuclear position variables in the problem. This is a generalization of the approximate factorization originally proposed by Born and Oppenheimer, the hope being that an ‘exact’ representation of Φ can be achieved in this form with φ and χ interpretable as ‘electronic’ and ‘nuclear’ wavefunctions respectively. We offer a mathematical analysis of these proposals that identifies ambiguities stemming mainly from the singularities in the Coulomb potential energy. (paper)

  14. Positioning Based on Factor Graphs

    Directory of Open Access Journals (Sweden)

    Simon Plass

    2007-01-01

    Full Text Available This paper covers location determination in wireless cellular networks based on time difference of arrival (TDoA measurements in a factor graphs framework. The resulting nonlinear estimation problem of the localization process for the mobile station cannot be solved analytically. The well-known iterative Gauss-Newton method as standard solution fails to converge for certain geometric constellations and bad initial values, and thus, it is not suitable for a general solution in cellular networks. Therefore, we propose a TDoA positioning algorithm based on factor graphs. Simulation results in terms of root-mean-square errors and cumulative density functions show that this approach achieves very accurate positioning estimates by moderate computational complexity.

  15. Shot-noise Fano factor

    Science.gov (United States)

    Rajdl, Kamil; Lansky, Petr

    2015-11-01

    A variability measure of the times of uniform events based on a shot-noise process is proposed and studied. The measure is inspired by the Fano factor, which we generalize by considering the time-weighted influence of the events given by a shot-noise response function. The sequence of events is assumed to be an equilibrium renewal process, and based on this assumption we present formulas describing the behavior of the variability measure. The formulas are derived for a general response function, restricted only by some natural conditions, but the main focus is given to the shot noise with exponential decrease. The proposed measure is analyzed and compared with the Fano factor.

  16. Fano factor determination for CZT

    International Nuclear Information System (INIS)

    Continued improvements in the manufacturing of Cd1-xZnxTe (CZT) material have resulted in a practical thermoelectrically cooled X-ray and gamma-ray detector of very high energy resolution. A high resolution spectroscopy system was used to measure the Fano factor in CZT at temperatures down to -40 C. The best resolution of the 5.9 keV 55Fe peak was measured to be 188 eV FWHM, while the best resolution of the 59.5 keV 241Am peak was measured to be 482 eV FWHM. The minimum measured Fano factor was 0.082, with several measurements yielding a value of 0.089 ± 0.005. With a resolution of 4.2 keV FWHM for the 662 keV peak of 137Cs, these detectors demonstrate excellent performance in detecting X-rays and gamma rays

  17. Nutritional Factors Affecting Mental Health.

    Science.gov (United States)

    Lim, So Young; Kim, Eun Jin; Kim, Arang; Lee, Hee Jae; Choi, Hyun Jin; Yang, Soo Jin

    2016-07-01

    Dietary intake and nutritional status of individuals are important factors affecting mental health and the development of psychiatric disorders. Majority of scientific evidence relating to mental health focuses on depression, cognitive function, and dementia, and limited evidence is available about other psychiatric disorders including schizophrenia. As life span of human being is increasing, the more the prevalence of mental disorders is, the more attention rises. Lists of suggested nutritional components that may be beneficial for mental health are omega-3 fatty acids, phospholipids, cholesterol, niacin, folate, vitamin B6, and vitamin B12. Saturated fat and simple sugar are considered detrimental to cognitive function. Evidence on the effect of cholesterol is conflicting; however, in general, blood cholesterol levels are negatively associated with the risk of depression. Collectively, the aims of this review are to introduce known nutritional factors for mental health, and to discuss recent issues of the nutritional impact on cognitive function and healthy brain aging. PMID:27482518

  18. Erp Systems Critical Success Factors

    Directory of Open Access Journals (Sweden)

    Islam K. Sowan

    2015-06-01

    Full Text Available The Enterprise Resources Planning (ERP systems are one of the highly complex systems in the information systems field; the implementations of this type of systems need a long time, high cost, and a lot of resources. Many factors affect the successful implementation of ERP system. The critical success factors (CSFs can be categorized as general, ICT related and software engineering or system life cycle (SLC related. This paper is a survey paper that identifies ERP systems CSFs in general and software engineering CSFs in specific. Also an agile methodology for ERP systems' implementations will be presented. Many existing ERP systems were surveyed and presented from ICT / software engineering point of view.

  19. Clustering-Based Matrix Factorization

    OpenAIRE

    Mirbakhsh, Nima; Ling, Charles X.

    2013-01-01

    Recommender systems are emerging technologies that nowadays can be found in many applications such as Amazon, Netflix, and so on. These systems help users to find relevant information, recommendations, and their preferred items. Slightly improvement of the accuracy of these recommenders can highly affect the quality of recommendations. Matrix Factorization is a popular method in Recommendation Systems showing promising results in accuracy and complexity. In this paper we propose an extension ...

  20. On factorization of multiparticle pentagons

    Directory of Open Access Journals (Sweden)

    A.V. Belitsky

    2015-08-01

    Full Text Available We address the near-collinear expansion of multiparticle NMHV amplitudes, namely, the heptagon and octagons in the dual language of null polygonal super Wilson loops. In particular, we verify multiparticle factorization of charged pentagon transitions in terms of pentagons for single flux-tube excitations within the framework of refined operator product expansion. We find a perfect agreement with available tree and one-loop data.

  1. Human Factors in Space Exploration

    Science.gov (United States)

    Jones, Patricia M.; Fiedler, Edna

    2010-01-01

    The exploration of space is one of the most fascinating domains to study from a human factors perspective. Like other complex work domains such as aviation (Pritchett and Kim, 2008), air traffic management (Durso and Manning, 2008), health care (Morrow, North, and Wickens, 2006), homeland security (Cooke and Winner, 2008), and vehicle control (Lee, 2006), space exploration is a large-scale sociotechnical work domain characterized by complexity, dynamism, uncertainty, and risk in real-time operational contexts (Perrow, 1999; Woods et ai, 1994). Nearly the entire gamut of human factors issues - for example, human-automation interaction (Sheridan and Parasuraman, 2006), telerobotics, display and control design (Smith, Bennett, and Stone, 2006), usability, anthropometry (Chaffin, 2008), biomechanics (Marras and Radwin, 2006), safety engineering, emergency operations, maintenance human factors, situation awareness (Tenney and Pew, 2006), crew resource management (Salas et aI., 2006), methods for cognitive work analysis (Bisantz and Roth, 2008) and the like -- are applicable to astronauts, mission control, operational medicine, Space Shuttle manufacturing and assembly operations, and space suit designers as they are in other work domains (e.g., Bloomberg, 2003; Bos et al, 2006; Brooks and Ince, 1992; Casler and Cook, 1999; Jones, 1994; McCurdy et ai, 2006; Neerincx et aI., 2006; Olofinboba and Dorneich, 2005; Patterson, Watts-Perotti and Woods, 1999; Patterson and Woods, 2001; Seagull et ai, 2007; Sierhuis, Clancey and Sims, 2002). The human exploration of space also has unique challenges of particular interest to human factors research and practice. This chapter provides an overview of those issues and reports on sorne of the latest research results as well as the latest challenges still facing the field.

  2. CEREBRAL PALSY : ANTENATAL RISK FACTORS

    OpenAIRE

    Srinivasa Rao; Vidyullatha; Subbalakshmi

    2015-01-01

    INTRODUCTION: Cerebral palsy (CP) is a group of permanent movement disorders that appear in early childhood. Cerebral palsy is caused by abnormal development or damage to the parts of the brain that control movement, balance, and posture. Most often the problems occur during pregnancy; however, they may also occur during childbirth, or shortly after birth. Often the cause is unknown. AIM: To study the different antenatal maternal risk factors associated with cere...

  3. HIV: Social and Environmental Factors

    Centers for Disease Control (CDC) Podcasts

    2012-02-01

    Dr. Kevin Fenton, Director of CDC’s National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, discusses how social and environmental factors may put African Americans at greater risk for HIV.  Created: 2/1/2012 by National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP).   Date Released: 2/1/2012.

  4. Cultural Factors in Business Negotiation

    Institute of Scientific and Technical Information of China (English)

    张薇

    2015-01-01

    When it comes to the intercultural business negotiation,a correct understanding of the cultural differences between the east and the west and the appropriate approach to the cultural conflicts are the preconditions for the success.This paper aims at putting forward effective strategies to tackle cross-cultural obstacles in the business negotiation through the comparative study of cultural factors in business negotiations.

  5. Environmental risk factors for autism

    OpenAIRE

    Dietert, Rodney R.; Janice M. Dietert; DeWitt, Jamie C.

    2011-01-01

    Autism is a devastating childhood condition that has emerged as an increasing social concern just as it has increased in prevalence in recent decades. Autism and the broader category of autism spectrum disorders are among the increasingly seen examples in which there is a fetal basis for later disease or disorder. Environmental, genetic, and epigenetic factors all play a role in determining the risk of autism and some of these effects appear to be transgenerational. Identification of the most...

  6. Matrix Factorizations and Kauffman Homology

    CERN Document Server

    Gukov, S; Gukov, Sergei; Walcher, Johannes

    2005-01-01

    The topological string interpretation of homological knot invariants has led to several insights into the structure of the theory in the case of sl(N). We study possible extensions of the matrix factorization approach to knot homology for other Lie groups and representations. In particular, we introduce a new triply graded theory categorifying the Kauffman polynomial, test it, and predict the Kauffman homology for several simple knots.

  7. Shared Services Management: Critical Factors

    OpenAIRE

    Shouhong Wang; Hai Wang

    2015-01-01

    The cloud computing technology has accelerated shared services in the government and private sectors. This paper proposes a research framework of critical success factors of shared services in the aspects of strategy identification, collaborative partnership networking, optimal shared services process re-designing, and new policies and regulations. A survey has been employed to test the hypotheses. The test results indicate that clear vision of strategies of shared services, long term busines...

  8. MAIN FACTORS INFLUENCING PROJECT SUCCESS

    OpenAIRE

    Ioana Beleiu; Emil Crisan; Razvan Nistor

    2015-01-01

    The high frequency of using projects in all fields determined the increasing importance of adequate project management. Considering the direct relationship between reaching projects’ objectives and the long term development of an organization, aspects regarding projects’ success and the success factors of projects are topics of great interest in project management literature. Reaching projects’ objectives in compliance with constraints of cost, time and performance is usually not sufficient t...

  9. Quality factor measurements at NTF

    International Nuclear Information System (INIS)

    The dose equivalent rate in the radiation field outside of the polydoor at the Neutron Therapy Facility has been measured, using a Chipmunk, assuming a quality factor (QF) of 5, to be 25 mrem/hr. This kind of dose rate if true introduced occupancy restrictions and NTF is operating under an exemption. Based on the previous CR-39 studies of the neutron field around NTF,and the amount of shielding around the NTF, it was difficult to believe that a significant neutron field exists in this area, and contributes to the measured dose rate. If the field was mostly due to gamma rays the QF setting on the Chipmunk could be reliably set to a value of one. One method of obtaining a qualitative understanding of the relative abundance of neutron and gamma contribution to the absorbed doses, is to measure the quality factor for the field. This was determined using a recombination chamber. The recombination chamber is a gas filled ion chamber that can measure the average quality factor of a radiation field of unknown composition and energy spectrum. To use the recombination chamber in an unknown field, one needs to measured a calibration curve using radiation fields of known quality factor. The individual neutron and gamma components of the radiation field were also determined in these studies by use of an Andersson-Braun counter to measure the dose equivalent rate due to neutrons, and a Cutup ion chamber to measure the gamma dose rate. The neutron dose equivalent rate in this area of NTF has been estimated by Vylet and is consistent with the present measurements

  10. Quality factor measurements at NTF

    Energy Technology Data Exchange (ETDEWEB)

    Vaziri, K.; Krueger, F.; Kroc, T.; Lauten, G.; Lennox, A.; Leveling, T.

    1993-12-17

    The dose equivalent rate in the radiation field outside of the polydoor at the Neutron Therapy Facility has been measured, using a Chipmunk, assuming a quality factor (QF) of 5, to be 25 mrem/hr. This kind of dose rate if true introduced occupancy restrictions and NTF is operating under an exemption. Based on the previous CR-39 studies of the neutron field around NTF,and the amount of shielding around the NTF, it was difficult to believe that a significant neutron field exists in this area, and contributes to the measured dose rate. If the field was mostly due to gamma rays the QF setting on the Chipmunk could be reliably set to a value of one. One method of obtaining a qualitative understanding of the relative abundance of neutron and gamma contribution to the absorbed doses, is to measure the quality factor for the field. This was determined using a recombination chamber. The recombination chamber is a gas filled ion chamber that can measure the average quality factor of a radiation field of unknown composition and energy spectrum. To use the recombination chamber in an unknown field, one needs to measured a calibration curve using radiation fields of known quality factor. The individual neutron and gamma components of the radiation field were also determined in these studies by use of an Andersson-Braun counter to measure the dose equivalent rate due to neutrons, and a Cutup ion chamber to measure the gamma dose rate. The neutron dose equivalent rate in this area of NTF has been estimated by Vylet and is consistent with the present measurements.

  11. Tissue Factor Structure and Function

    Directory of Open Access Journals (Sweden)

    Saulius Butenas

    2012-01-01

    Full Text Available Tissue factor (TF is an integral membrane protein that is essential to life. It is a component of the factor VIIa-TF complex enzyme and plays a primary role in both normal hemostasis and thrombosis. With a vascular injury, TF becomes exposed to blood and binds plasma factor VIIa, and the resulting complex initiates a series of enzymatic reactions leading to clot formation and vascular sealing. Many cells, both healthy, and tumor cells, produce detectable amounts of TF, especially when they are stimulated by various agents. Despite the relative simplicity and small size of TF, there are numerous contradictory reports about the synthesis and presentation of TF on blood cells and circulation in normal blood either on microparticles or as a soluble protein. Another subject of controversy is related to the structure/function of TF. It has been almost commonly accepted that cell-surface-associated TF has low (if any activity, that is, is “encrypted” and requires specific conditions/reagents to become active, that is, “decrypted.” However there is a lack of agreement related to the mechanism and processes leading to alterations in TF function. In this paper TF structure, presentation, and function, and controversies concerning these features are discussed.

  12. Factor V Leiden and Inflammation

    Science.gov (United States)

    Perez-Pujol, Silvia; Aras, Omer; Escolar, Gines

    2012-01-01

    Factor V Leiden, is a variant of human factor V (FV), also known as proaccelerin, which leads to a hypercoagulable state. Along these years, factor V Leiden (FVL) has been studied from the pathophysiologic point of view, and research has been focused on finding clinical approaches for the management of the FVL associated to a trombophilic state. Less attention has been paid about the possible role of FVL in inflammatory conditions known to be present in different disorders such as uremia, cirrhosis, liver transplantation, depression as well as sepsis, infection or, inflammatory bowel disease (IBD). Whether platelet FVL will increase the activation of coagulation and/or in which proportion is able to determine the final outcome in the previously mentioned inflammatory conditions is a subject that remains uncertain. This paper will review the association of FVL with inflammation. Specifically, it will analyze the important role of the endothelium and the contribution of other inflammatory components involved at both the immune and vascular levels. This paper will also try to emphasize the importance of being a FVL carrier in associations to diseases where a chronic inflammation occurs, and how this condition may be determinant in the progression and outcome of a specific clinic situation. PMID:22666576

  13. Column: Factors Affecting Data Decay

    Directory of Open Access Journals (Sweden)

    Kevin Fairbanks

    2012-06-01

    Full Text Available In nuclear physics, the phrase decay rate is used to denote the rate that atoms and other particles spontaneously decompose. Uranium-235 famously decays into a variety of daughter isotopes including Thorium and Neptunium, which themselves decay to others. Decay rates are widely observed and wildly different depending on many factors, both internal and external. U-235 has a half-life of 703,800,000 years, for example, while free neutrons have a half-life of 611 seconds and neutrons in an atomic nucleus are stable.We posit that data in computer systems also experiences some kind of statistical decay process and thus also has a discernible decay rate. Like atomic decay, data decay fluctuates wildly. But unlike atomic decay, data decay rates are the result of so many different interplaying processes that we currently do not understand them well enough to come up with quantifiable numbers. Nevertheless, we believe that it is useful to discuss some of the factors that impact the data decay rate, for these factors frequently determine whether useful data about a subject can be recovered by forensic investigation.(see PDF for full column

  14. Factor V Leiden and Inflammation

    Directory of Open Access Journals (Sweden)

    Silvia Perez-Pujol

    2012-01-01

    Full Text Available Factor V Leiden, is a variant of human factor V (FV, also known as proaccelerin, which leads to a hypercoagulable state. Along these years, factor V Leiden (FVL has been studied from the pathophysiologic point of view, and research has been focused on finding clinical approaches for the management of the FVL associated to a trombophilic state. Less attention has been paid about the possible role of FVL in inflammatory conditions known to be present in different disorders such as uremia, cirrhosis, liver transplantation, depression as well as sepsis, infection or, inflammatory bowel disease (IBD. Whether platelet FVL will increase the activation of coagulation and/or in which proportion is able to determine the final outcome in the previously mentioned inflammatory conditions is a subject that remains uncertain. This paper will review the association of FVL with inflammation. Specifically, it will analyze the important role of the endothelium and the contribution of other inflammatory components involved at both the immune and vascular levels. This paper will also try to emphasize the importance of being a FVL carrier in associations to diseases where a chronic inflammation occurs, and how this condition may be determinant in the progression and outcome of a specific clinic situation.

  15. Factores de riesgo de la enfermedad periodontal: factores genéticos Risks factors in periodontal diseases: genetic factors

    Directory of Open Access Journals (Sweden)

    M. Rioboo Crespo

    2005-08-01

    Full Text Available Hoy en día y tras numerosos estudios epidemiológicos, se acepta el concepto de la existencia de determinados factores de riesgo que van a modular la susceptibilidad o resistencia del hospedador a padecer enfermedad periodontal, por lo tanto, en el desarrollo van a intervenir varias causas considerándose dicha patología de etiología multifactorial. De este modo, las enfermedades periodontales son producidas por una interacción de un agente microbiano único o múltiple considerado como el factor etiológico primario necesario pero no suficiente, un huésped más o menos susceptible y unos factores ambientales que influyen sobre ambos. La importancia de la herencia y la genética para el conocimiento de la etiopatogenia de la enfermedad periodontal y para la práctica clínica en general fueron destacadas desde muy temprano, pero las complejas interacciones que ocurren entre los mecanismos de respuesta del hospedador y la acción de los microorganismos patógenos han hecho que las aclaraciones sobre el papel de los factores genéticos en la enfermedad periodontal sean más difíciles. Aun así, la influencia de los factores genéticos en la periodontitis parece ser diferente para los distintos tipos de enfermedad periodontal y ha sido estudiada en cada una de las periodontitis definidas. En general, se considera que hay suficiente base científica a favor de la presencia de factores genéticos en la aparición de periodontitis agresivas. En las periodontitis crónicas, en cambio, la evidencia de la participación genética es menos manifiesta. Numerosos estudios ponen en evidencia que existe una asociación entre las periodontitis y una variación genética de determinados genes (polimorfismos que codifican diferentes citoquinas proinflamatorias y mediadores involucrados en la etiopatogénia de la enfermedad periodontal como la IL-1,IL- 4, IL-10,TNF, PGE2. El fenotipo HLA (Human Leukocite Antigen, también ha sido investigado como posible

  16. Optimal factorizations of rational numbers using factorization trees

    OpenAIRE

    Samuels, Charles L.; Strunk, Tanner J.

    2014-01-01

    Let $m_t(\\alpha)$ denote the $t$-metric Mahler measure of the algebraic number $\\alpha$. Recent work of the first author established that the infimum in $m_t(\\alpha)$ is attained by a single point $\\bar\\alpha = (\\alpha_1,\\ldots,\\alpha_N)\\in \\overline{\\mathbb Q}^N$ for all sufficiently large $t$. Nevertheless, no efficient method for locating $\\bar \\alpha$ is known. In this article, we define a new tree data structure, called a factorization tree, which enables us to find $\\bar\\alpha$ when $\\a...

  17. Factor VIII inhibitors in mild haemophilia A

    NARCIS (Netherlands)

    Bril, Wendy Simone

    2003-01-01

    The X-linked bleeding disorder haemophilia A is due to a deficiency or functional defect of coagulation factor VIII. The bleeding tendency can be corrected by administration of factor VIII concentrates. A serious complication of factor VIII replacement therapy is the development of anti-factor VIII

  18. Blood coagulation factor VIII: An overview

    Indian Academy of Sciences (India)

    G M Bhopale; R K Nanda

    2003-12-01

    Factor VIII (FVIII) functions as a co-factor in the blood coagulation cascade for the proteolytic activation of factor X by factor IXa. Deficiency of FVIII causes hemophilia A, the most commonly inherited bleeding disorder. This review highlights current knowledge on selected aspects of FVIII in which both the scientist and the clinician should be interested.

  19. 14 CFR 31.43 - Fitting factor.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fitting factor. 31.43 Section 31.43... STANDARDS: MANNED FREE BALLOONS Design Construction § 31.43 Fitting factor. (a) A fitting factor of at least... structure. This factor applies to all parts of the fitting, the means of attachment, and the bearing on...

  20. 23 CFR 650.707 - Rating factor.

    Science.gov (United States)

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Rating factor. 650.707 Section 650.707 Highways FEDERAL..., STRUCTURES, AND HYDRAULICS Discretionary Bridge Candidate Rating Factor § 650.707 Rating factor. (a) The.... ER15OC02.010 The lower the rating factor, the higher the priority for selection and funding. (b) The...

  1. 5 CFR 841.404 - Demographic factors.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Demographic factors. 841.404 Section 841... factors. (a) The Office of Personnel Management (OPM) will consider the factors listed below in determining normal cost percentages. To the extent data are available for the factor by specific category...

  2. 14 CFR 23.619 - Special factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Special factors. 23.619 Section 23.619... Special factors. The factor of safety prescribed in § 23.303 must be multiplied by the highest pertinent special factors of safety prescribed in §§ 23.621 through 23.625 for each part of the structure...

  3. 14 CFR 25.619 - Special factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Special factors. 25.619 Section 25.619... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction General § 25.619 Special factors. The factor of safety prescribed in § 25.303 must be multiplied by the highest pertinent special factor of...

  4. 14 CFR 23.621 - Casting factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Casting factors. 23.621 Section 23.621... Casting factors. (a) General. The factors, tests, and inspections specified in paragraphs (b) through (d... do not support structural loads. (b) Bearing stresses and surfaces. The casting factors specified...

  5. 24 CFR 598.305 - Designation factors.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 3 2010-04-01 2010-04-01 false Designation factors. 598.305... Designation Process § 598.305 Designation factors. In choosing among nominated urban areas eligible for... connection with the strategic plan (see § 598.215(b)); and (c) Other factors. Other factors established...

  6. Structural properties of close II$_1$ factors

    OpenAIRE

    Cameron, Jan; Christensen, Erik; Sinclair, Allan M.; Smith, Roger R.; White, Stuart; Wiggins, Alan D.

    2016-01-01

    We show that a number of key structural properties transfer between sufficiently close II$_1$ factors, including solidity, strong solidity, uniqueness of Cartan masas and property $\\Gamma$. We also examine II$_1$ factors close to tensor product factors, showing that such factors also factorise as a tensor product in a fashion close to the original.

  7. Dopamine receptor regulating factor, DRRF: a zinc finger transcription factor.

    Science.gov (United States)

    Hwang, C K; D'Souza, U M; Eisch, A J; Yajima, S; Lammers, C H; Yang, Y; Lee, S H; Kim, Y M; Nestler, E J; Mouradian, M M

    2001-06-19

    Dopamine receptor genes are under complex transcription control, determining their unique regional distribution in the brain. We describe here a zinc finger type transcription factor, designated dopamine receptor regulating factor (DRRF), which binds to GC and GT boxes in the D1A and D2 dopamine receptor promoters and effectively displaces Sp1 and Sp3 from these sequences. Consequently, DRRF can modulate the activity of these dopamine receptor promoters. Highest DRRF mRNA levels are found in brain with a specific regional distribution including olfactory bulb and tubercle, nucleus accumbens, striatum, hippocampus, amygdala, and frontal cortex. Many of these brain regions also express abundant levels of various dopamine receptors. In vivo, DRRF itself can be regulated by manipulations of dopaminergic transmission. Mice treated with drugs that increase extracellular striatal dopamine levels (cocaine), block dopamine receptors (haloperidol), or destroy dopamine terminals (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) show significant alterations in DRRF mRNA. The latter observations provide a basis for dopamine receptor regulation after these manipulations. We conclude that DRRF is important for modulating dopaminergic transmission in the brain. PMID:11390978

  8. Psychological factors and coronary heart disease

    OpenAIRE

    Khayyam-Nekouei, Zohreh; Neshatdoost, Hamidtaher; Yousefy, Alireza; Sadeghi, Masoumeh; Manshaee, Gholamreza

    2013-01-01

    BACKGROUND Although psychological factors play an important role in coronary heart diseases (CHD), it seems there is a need for more researches in this respect. The present study aimed to review psychological factors, including depression, anxiety and stress related to etiology and prognosis of CHD. METHODS This was a review on medical and psychological literatures, particularly in the years 1995-2012. RESULTS As protective factor or risk factor, psychological factors play an important role i...

  9. Factorization of the tenth Fermat number

    Science.gov (United States)

    Brent, Richard P.

    We describe the complete factorization of the tenth Fermat number F_{10} by the elliptic curve method (ECM). F_{10} is a product of four prime factors with 8, 10, 40 and 252 decimal digits. The 40-digit factor was found after about 140 Mflop-years of computation. We also discuss the complete factorization of other Fermat numbers by ECM, and summarize the factorizations of F_5, ..., F_{11}.

  10. Determining Factors of Subsidiary Development

    DEFF Research Database (Denmark)

    Pedersen, Torben

    (the depth of activities) and level of integration in the internal MNC-network. Birkinshaw and Hood (1998a) have in their seminal paper proposed a model where subsidiary development is determined by three factors: Headquarter assignment, dynamism of local business environment and subsidiary initiatives......Subsidiary development is a multi-dimensional construct that cannot be captured just by looking at subsidiary roles, activities, etc. Three distinct dimensions of subsidiary development are identified and these are: scope of subsidiary (the breadth of activities), level of subsidiary competence...

  11. Human Factors in Space Flight

    Science.gov (United States)

    Woolford, Barbara J.; Mount, Frances

    2005-01-01

    After forty years of experience with human space flight (Table 1), the current emphasis is on the design of space vehicles, habitats, and missions to ensure mission success. What lessons have we learned that will affect the design of spacecraft for future space exploration, leading up to exploring Mars? This chapter addresses this issue in four sections: Anthropometry and Biomechanics; Environmental Factors; Habitability and Architecture; and Crew Personal Sustenance. This introductory section introduces factors unique to space flight. A unique consideration for design of a habitable volume in a space vehicle is the lack of gravity during a space flight, referred to as microgravity. This affects all aspects of life, and drives special features in the habitat, equipment, tools, and procedures. The difference in gravity during a space mission requires designing for posture and motion differences. In Earth s gravity, or even with partial gravity, orientation is not a variable because the direction in which gravity acts defines up and down. In a microgravity environment the working position is arbitrary; there is no gravity cue. Orientation is defined primarily through visual cues. The orientation within a particular crew station or work area is referred to as local vertical, and should be consistent within a module to increase crew productivity. Equipment was intentionally arranged in various orientations in one module on Skylab to assess the efficiency in use of space versus the effects of inconsistent layout. The effects of that arrangement were confusion on entering the module, time spent in re-orientation, and conflicts in crew space requirements when multiple crew members were in the module. Design of a space vehicle is constrained by the three major mission drivers: mass, volume and power. Each of these factors drives the cost of a mission. Mass and volume determine the size of the launch vehicle directly; they can limit consumables such as air, water, and

  12. Oil: economic and political factors

    International Nuclear Information System (INIS)

    This article deals with the evolution of the international petroleum sector since 1973 with a special view to interdependence between the economic and political factors that influence it. Two issues are focused upon: (1) the effects of the nationalization of oil companies on the sharing of oil rents and on changes in the structure of the oil market; and (2) the determination of oil prices. The latter involves a discussion of, on the one hand, the political and economic behaviour of the United States and Saudi Arabia and, on the other, the combination of cooperation and conflict that has tended to characterize relations among OPEC countries. (author). 30 refs

  13. Factores de riesgo en epilepsia

    Directory of Open Access Journals (Sweden)

    José William Cornejo Ochoa

    1990-03-01

    Full Text Available e analizaron 1.961 encuestas correspondientes a 1.131 casos de epilepsia y 830 controles, con el objeto de medir la asociación entre
    esta enfermedad y las siguientes variables: factor heredo-familiar, riesgo obstétrico, infecciones del sistema nervioso central, infecciones virales de la infancia y trauma del cráneo. Se validó el formulario analizando la presencia de infecciones urinarias, la colaboración a la entrevista y la duración de ésta; no se hallaron, en tales aspectos,
    diferencias significativas entre los casos y los controles.

  14. Rheumatoid factor and tobacco exposure

    Directory of Open Access Journals (Sweden)

    Skare Thelma Larocca

    2002-01-01

    Full Text Available This study was carried out to analyse the possible influence of smoking on the positivity of rheumatoid factor (RF in healthy individuals in the region of Curitiba, Brazil. One hundred fifty blood donors (84 smokers and 66 non-smokers were studied for the presence of RF using nephelometry. Smoking was found not to be correlated to the positivity of RF, independently of the smokers sex (men with p=0.09 and women with p=0.49, the number of cigarettes/day (p=0.20, duration of smoking (p=0.18 and cumulative exposure (time X quantity to cigarettes (p=0.13.

  15. Strange chiral nucleon form factors

    CERN Document Server

    Hemmert, T R; Meißner, Ulf G; Hemmert, Thomas R.; Kubis, Bastian; Meissner, Ulf-G.

    1999-01-01

    We investigate the strange electric and magnetic form factors of the nucleon in the framework of heavy baryon chiral perturbation theory to third order in the chiral expansion. All counterterms can be fixed from data. In particular, the two unknown singlet couplings can be deduced from the parity-violating electron scattering experiments performed by the SAMPLE and the HAPPEX collaborations. Within the given uncertainties, our analysis leads to a small and positive electric strangeness radius, $ = (0.05 \\pm 0.16) fm^2$. We also deduce the consequences for the upcoming MAMI A4 experiment.

  16. Phenomenological applications of T factorization

    Indian Academy of Sciences (India)

    Yong-Yeon Keum

    2004-12-01

    We discuss applications of the perturbative QCD approach in the exclusive non-leptonic two-body -meson decays. We briefly review its ingredients and some important theoretical issues on the factorization approach. PQCD results are compatible with present experimental data for charmless -meson decays. We predict the possibility of large direct CP asymmetry in $B^{0} → + − (23 ± 7\\%) and 0 → + − (−17 ± 5\\%). We also investigate the branching ratios, CP asymmetry and isospin symmetry breaking in radiative $B → (*/ρ) decays.

  17. NAC transcription factors in senescence

    DEFF Research Database (Denmark)

    Podzimska-Sroka, Dagmara; O'Shea, Charlotte; Gregersen, Per L.;

    2015-01-01

    Within the last decade, NAC transcription factors have been shown to play essential roles in senescence, which is the focus of this review. Transcriptome analyses associate approximately one third of Arabidopsis NAC genes and many crop NAC genes with senescence, thereby implicating NAC genes...... as important regulators of the senescence process. The consensus DNA binding site of the NAC domain is used to predict NAC target genes, and protein interaction sites can be predicted for the intrinsically disordered transcription regulatory domains of NAC proteins. The molecular characteristics...

  18. Kadison–Kastler stable factors

    OpenAIRE

    Cameron, Jan; Christensen, Erik; Sinclair, Allan M.; Smith, Roger R.; White, Stuart; Wiggins, Alan D.

    2014-01-01

    A conjecture of Kadison and Kastler from 1972 asks whether sufficiently close operator algebras in a natural uniform sense must be small unitary perturbations of one another. For $n\\geq3$ and a free, ergodic, probability measure-preserving action of $\\operatorname {SL}_{n}(\\mathbb{Z})$ on a standard nonatomic probability space $(X,\\mu)$ , write $M=(L^{\\infty}(X,\\mu)\\rtimes\\operatorname {SL}_{n}(\\mathbb{Z}))\\,\\overline {\\otimes }\\,R$ , where $R$ is the hyperfinite II1-factor. We show that when...

  19. Making a tooth: growth factors, transcription factors, and stem cells

    Institute of Scientific and Technical Information of China (English)

    Yah Ding ZHANG; Zhi CHEN; Yi Qiang SONG; Chao LIU; Yi Ping CHEN

    2005-01-01

    Mammalian tooth development is largely dependent on sequential and reciprocal epithelial-mesenchymal interactions.These processes involve a series of inductive and permissive interactions that result in the determination, differentiation,and organization of odontogenic tissues. Multiple signaling molecules, including BMPs, FGFs, Shh, and Wnt proteins,have been implicated in mediating these tissue interactions. Transcription factors participate in epithelial-mesenchymal interactions via linking the signaling loops between tissue layers by responding to inductive signals and regulating the expression of other signaling molecules. Adult stem cells are highly plastic and multipotent. These cells including dental pulp stem cells and bone marrow stromal cells could be reprogrammed into odontogenic fate and participated in tooth formation. Recent progress in the studies of molecular basis of tooth development, adult stem cell biology, and regeneration will provide fundamental knowledge for the realization of human tooth regeneration in the near future.

  20. Human Factors Checklist: Think Human Factors - Focus on the People

    Science.gov (United States)

    Miller, Darcy; Stelges, Katrine; Barth, Timothy; Stambolian, Damon; Henderson, Gena; Dischinger, Charles; Kanki, Barbara; Kramer, Ian

    2016-01-01

    A quick-look Human Factors (HF) Checklist condenses industry and NASA Agency standards consisting of thousands of requirements into 14 main categories. With support from contractor HF and Safety Practitioners, NASA developed a means to share key HF messages with Design, Engineering, Safety, Project Management, and others. It is often difficult to complete timely assessments due to the large volume of HF information. The HF Checklist evolved over time into a simple way to consider the most important concepts. A wide audience can apply the checklist early in design or through planning phases, even before hardware or processes are finalized or implemented. The checklist is a good place to start to supplement formal HF evaluation. The HF Checklist was based on many Space Shuttle processing experiences and lessons learned. It is now being applied to ground processing of new space vehicles and adjusted for new facilities and systems.

  1. Growth factors in cystic fibrosis

    Directory of Open Access Journals (Sweden)

    Negar Khalighi

    2016-01-01

    Full Text Available Introduction: Cystic fibrosis is one of the most common autosomal recessive diseases that affects sweat glands and mucosa. CF is a hereditary disease with annual incidence of about 2500 new cases in United Kingdom. Insulin-like growth factor-1 (IGF-1 and insulin-like growth factor binding protein-3 levels decrease in CF. The aim of this study was to assess the role of growth peptides in patients with CF. Method: We searched PubMed, Google scholar, IranMedex, and Scientific Information Database (SID in September 2012 to April 2014. We included clinical studies with available abstracts and full texts that were in English or Persian languages. Manual searching was conducted within the reference lists of articles. Two reviewers independently applied eligibility criteria, assessed quality, and extracted data.Result: The earliest study was published in 1997 and the most recent one was in 2014. Study participants were adults in 3 studies (20% and 12 studies (80% were conducted in children. Patients with CF have lower levels of IGF-1 and there is a significant correlation between IGF-1 levels and growth index in patients with CF.Conclusions: IGF-1 decreases in children with CF and might be the cause of poor growth and low body mass index in these children.

  2. Factors influencing pacing in triathlon

    Directory of Open Access Journals (Sweden)

    Wu SSX

    2014-09-01

    Full Text Available Sam SX Wu,1 Jeremiah J Peiffer,2 Jeanick Brisswalter,3 Kazunori Nosaka,1 Chris R Abbiss1 1Centre for Exercise and Sports Science Research, School of Exercise and Health Sciences, Edith Cowan University, Perth, WA, Australia; 2School of Psychology and Exercise Science, Murdoch University, Perth, WA, Australia; 3Laboratory of Human Motricity, Education Sport and Health, University of Nice Sophia Antipolis, Nice, France Abstract: Triathlon is a multisport event consisting of sequential swim, cycle, and run disciplines performed over a variety of distances. This complex and unique sport requires athletes to appropriately distribute their speed or energy expenditure (ie, pacing within each discipline as well as over the entire event. As with most physical activity, the regulation of pacing in triathlon may be influenced by a multitude of intrinsic and extrinsic factors. The majority of current research focuses mainly on the Olympic distance, whilst much less literature is available on other triathlon distances such as the sprint, half-Ironman, and Ironman distances. Furthermore, little is understood regarding the specific physiological, environmental, and interdisciplinary effects on pacing. Therefore, this article discusses the pacing strategies observed in triathlon across different distances, and elucidates the possible factors influencing pacing within the three specific disciplines of a triathlon. Keywords: cycle, endurance, multisport, pacing strategy, run, swim

  3. Heat differentiated complement factor profiling.

    Science.gov (United States)

    Hamsten, Carl; Skattum, Lillemor; Truedsson, Lennart; von Döbeln, Ulrika; Uhlén, Mathias; Schwenk, Jochen M; Hammarström, Lennart; Nilsson, Peter; Neiman, Maja

    2015-08-01

    Complement components and their cascade of reactions are important defense mechanisms within both innate and adaptive immunity. Many complement deficient patients still remain undiagnosed because of a lack of high throughput screening tools. Aiming towards neonatal proteome screening for immunodeficiencies, we used a multiplex profiling approach with antibody bead arrays to measure 9 complement proteins in serum and dried blood spots. Several complement components have been described as heat sensitive, thus their heat-dependent detectability was investigated. Using sera from 16 patients with complement deficiencies and 23 controls, we confirmed that the proteins C1q, C2, C3, C6, C9 and factor H were positively affected by heating, thus the identification of deficient patients was improved when preheating samples. Measurements of C7, C8 and factor I were negatively affected by heating and non-heated samples should be used in analysis of these components. In addition, a proof of concept study demonstrated the feasibility of labeling eluates from dried blood spots to perform a subsequent correct classification of C2-deficiencies. Our study demonstrates the potential of using multiplexed single binder assays for screening of complement components that open possibilities to expand such analysis to other forms of deficiencies.

  4. Mycobacterium tuberculosis: factores de virulencia

    Directory of Open Access Journals (Sweden)

    Reinier Borrero

    2011-04-01

    Full Text Available Mycobacterium tuberculosis es el agente causal de la tuberculosis, una de las enfermedades infecciosas más letales en el mundo. La única vacuna disponible para su control es el BCG, sin embargo, falla en la protección contra la tuberculosis pulmonar, siendo esta la forma más frecuente y responsable de la diseminación. La identificación de factores de virulencia del microorganismo causal pudiera ayudar en el desarrollo de un nuevo candidato vacunal que sea capaz de neutralizar la acción de esos determinantes patogénicos. El empleo de diferentes modelos animales ha permitido reproducir las etapas de la enfermedad, así como medir o cuantificar la virulencia de las distintas cepas circulantes de Mycobacterium tuberculosis. Las mutaciones génicas y otras técnicas de biología molecular han posibilitado dilucidar los genes específicos involucrados en la virulencia de este microorganismo que codifican para múltiples y complejos factores de diferente naturaleza.

  5. Posttransplant Erythrocytosis and Risk Factors

    Directory of Open Access Journals (Sweden)

    Emre ERDEM

    2011-09-01

    Full Text Available OBJECTIVE: The aim of this study was to determine the prevalence and risk factors of posttransplant erythrocytosis (PTE. MATERIAL and METHODS: The study included 96 patients who received a renal allograft between 2005-2009 years. PTE was defined as an elevated hematocrit level greater than 51% after renal transplantation in patients receiving an allograft. RESULTS: Of the 96 adult kidney recipients, 15 (15,6% developed PTE. The mean time from transplantation to diagnosis was 7,3 ± 2,8 months ( range, 4,5-13 months . Mean serum creatinine was 1,12 ±0,3 mg/dl (0,8-1,99 mg/dl at the diagnosis of PTE. PTE was more frequent in male patients (p<0.05 and the patients with a long duration on dialysis prior to transplantation (p<0.05. There was no significant difference in patient age, donor source, donor age and immunosuppressive therapy on comparing the PTE group and non PTE groups. None of the patients with erythrocytosis experienced thromboembolic events during follow-up. CONCLUSION: PTE developed in the first year after transplantation. Male gender and a long duration on dialysis prior to transplantation are risk factors of PTE.

  6. Male factor infertility and ART

    Institute of Scientific and Technical Information of China (English)

    Herman Tournaye

    2012-01-01

    For years,the management and treatment of male factor infertility has been ‘experience’ and not ‘evidence’ based.Although not evidence-based,current clinical practice involves extensive use of assisted reproductive techniques (ART).Where specific treatments are not indicated or have failed,ART have become popular adjunctive treatments for alleviating male factor infertility.According to the limited evidence available,intrauterine insemination (IUI) may be considered as a first-line treatment in a couple in which the female partner has a normal fertility status and at least 1x 106 progressively motile spermatozoa are recovered after sperm preparation.If no pregnancy is achieved after 3-6 cycles of IUI,optimized in vitro fertilization (IVF) can be proposed.When less than 0.5x 106 progressively motile spermatozoa are obtained after seminal fluid processing or sperm are recovered surgically from the testis or epididymis,intracytoplasmic sperm injection (ICSI) should be performed.Although the outcome of no other ART has ever been scrutinized as much before,no large-scale ‘macroproblems’ have as yet been observed after ICSI.Yet,ICSI candidates should be rigorously screened before embarking on IVF or ICSI,and thoroughly informed of the limitations of our knowledge on the hereditary aspects of male infertility and the safety aspects of ART.

  7. Automatic Power Factor Correction Using Capacitive Bank

    Directory of Open Access Journals (Sweden)

    Mr.Anant Kumar Tiwari,

    2014-02-01

    Full Text Available The power factor correction of electrical loads is a problem common to all industrial companies. Earlier the power factor correction was done by adjusting the capacitive bank manually [1]. The automated power factor corrector (APFC using capacitive load bank is helpful in providing the power factor correction. Proposed automated project involves measuring the power factor value from the load using microcontroller. The design of this auto-adjustable power factor correction is to ensure the entire power system always preserving unity power factor. The software and hardware required to implement the suggested automatic power factor correction scheme are explained and its operation is described. APFC thus helps us to decrease the time taken to correct the power factor which helps to increase the efficiency.

  8. Factors Affecting Aerosol Radiative Forcing

    Science.gov (United States)

    Wang, Jingxu; Lin, Jintai; Ni, Ruijing

    2016-04-01

    Rapid industrial and economic growth has meant a large amount of aerosols in the atmosphere with strong radiative forcing (RF) upon the climate system. Over parts of the globe, the negative forcing of aerosols has overcompensated for the positive forcing of greenhouse gases. Aerosol RF is determined by emissions and various chemical-transport-radiative processes in the atmosphere, a multi-factor problem whose individual contributors have not been well quantified. In this study, we analyze the major factors affecting RF of secondary inorganic aerosols (SIOAs, including sulfate, nitrate and ammonium), primary organic aerosol (POA), and black carbon (BC). We analyze the RF of aerosols produced by 11 major regions across the globe, including but not limited to East Asia, Southeast Asia, South Asia, North America, and Western Europe. Factors analyzed include population size, per capita gross domestic production (GDP), emission intensity (i.e., emissions per unit GDP), chemical efficiency (i.e., mass per unit emissions) and radiative efficiency (i.e., RF per unit mass). We find that among the 11 regions, East Asia produces the largest emissions and aerosol RF, due to relatively high emission intensity and a tremendous population size. South Asia produce the second largest RF of SIOA and BC and the highest RF of POA, in part due to its highest chemical efficiency among all regions. Although Southeast Asia also has large emissions, its aerosol RF is alleviated by its lowest chemical efficiency. The chemical efficiency and radiative efficiency of BC produced by the Middle East-North Africa are the highest across the regions, whereas its RF is lowered by a small per capita GDP. Both North America and Western Europe have low emission intensity, compensating for the effects on RF of large population sizes and per capita GDP. There has been a momentum to transfer industries to Southeast Asia and South Asia, and such transition is expected to continue in the coming years. The

  9. Neurodevelopmental risk factors in schizophrenia

    Directory of Open Access Journals (Sweden)

    Lobato M.I.

    2001-01-01

    Full Text Available The authors review environmental and neurodevelopmental risk factors for schizophrenic disorders, with emphasis on minor physical anomalies, particularly craniofacial anomalies and dermatoglyphic variations. The high prevalence of these anomalies among schizophrenic subjects supports the neurodevelopmental theory of the etiology of schizophrenia, since they suggest either genetically or epigenetically controlled faulty embryonic development of structures of ectodermal origin like brain and skin. This may disturb neurodevelopment that in turn may cause these subjects to be at increased risk for the development of schizophrenia and related disorders. The precise confirmation of this theory, at least in some cases, will provide further understanding of these illnesses, allowing easy and inexpensive identification of subjects at risk and providing guidelines for the development of new pharmacological interventions for early treatment and even for primary prevention of the illness.

  10. Molecular Risk Factors for Schizophrenia.

    Science.gov (United States)

    Modai, Shira; Shomron, Noam

    2016-03-01

    Schizophrenia (SZ) is a complex and strongly heritable mental disorder, which is also associated with developmental-environmental triggers. As opposed to most diagnosable diseases (yet similar to other mental disorders), SZ diagnosis is commonly based on psychiatric evaluations. Recently, large-scale genetic and epigenetic approaches have been applied to SZ research with the goal of potentially improving diagnosis. Increased computational analyses and applied statistical algorithms may shed some light on the complex genetic and epigenetic pathways contributing to SZ pathogenesis. This review discusses the latest advances in molecular risk factors and diagnostics for SZ. Approaches such as these may lead to a more accurate definition of SZ and assist in creating extended and reliable clinical diagnoses with the potential for personalized treatment.

  11. [Factors that alter taste perception].

    Science.gov (United States)

    Maffeis, E R; Silva-Netto, C R

    1990-01-01

    Dysfunction of taste perception is a significant problem for many individuals. Taste anomalies may affect health not only by directly affecting liquid and solid food intake, but also by creating a state of depression due to the loss of an important source of pleasure. Many factors alter taste perception, such as lesions of the oral mucosa, cigarette smoking, radiation, chemotherapy, renal disease, hepatitis, leprosy, hormones, nutrition, use of dentures, medications, and aging. Gum or ice chewing may temporarily help loss of taste. Patients should be encouraged to chew their food thoroughly, alternating the sides of the mouth, or alternating different foods. Unfortunately, in many cases there is no cure for this alteration, and patience is then the only possibility.

  12. Psychological factors affecting equine performance

    Directory of Open Access Journals (Sweden)

    McBride Sebastian D

    2012-09-01

    Full Text Available Abstract For optimal individual performance within any equestrian discipline horses must be in peak physical condition and have the correct psychological state. This review discusses the psychological factors that affect the performance of the horse and, in turn, identifies areas within the competition horse industry where current behavioral research and established behavioral modification techniques could be applied to further enhance the performance of animals. In particular, the role of affective processes underpinning temperament, mood and emotional reaction in determining discipline-specific performance is discussed. A comparison is then made between the training and the competition environment and the review completes with a discussion on how behavioral modification techniques and general husbandry can be used advantageously from a performance perspective.

  13. AGROECOLOGICAL FACTORS OF FOOD SECURITY

    Directory of Open Access Journals (Sweden)

    L. Moldavan

    2014-09-01

    Full Text Available An experience of development of forms of economy in developed countries is analysed. Ways of development of domestic agriculture are proposed. The paper proved that Ukraine needs a new model of agriculture that was based not on the dynamic growth market of export production, and the balanced development of multipurpose field, which meets the needs of the country in food and foreign exchange earnings, warned to the depletion of natural resources. The extent of devastating effects of industrial model of agriculture development, which is oriented on economic growth without social and environmental price of its growth is revealed. Retrospective analysis of entry in international practice like formal institutional status of an alternative model in which an economic function of a branch (production and income is balanced with ecological (conservation potential land and social (food security is realized. Basic principles of ecologically oriented agriculture as a factor in long-term food security are formulated.

  14. Factors Behind Industrial Profit Growth

    Institute of Scientific and Technical Information of China (English)

    郑玉歆; 李玉红

    2008-01-01

    This paper analyzes Chinese enterprise industrial profit distribution and profitability rise between 1998 and 2005. Looking at it from the perspective of drivers of total growth, this paper will provide an in-depth analysis of the origins and industry-level factors involved in this growth. It reaches the conclusion that structural change in profits was the main driving force for profit increases, to which heavy industry contributed greatly. Light and machine building industry profit rates improved due to increases in productivity levels, while energy and raw material industry profits increased due to increases in product prices. In addition, average wages grew slower than GDP, and wages among industries varied widely. In general however, this paper sets out to determine which enterprises gained from increases in industrial profitability, and how this gain came about.

  15. Human factors reliability Benchmark exercise

    International Nuclear Information System (INIS)

    The Joint Research Centre of the European Commission has organized a Human Factors Reliability Benchmark Exercise (HF-RBE) with the aim of assessing the state of the art in human reliability modelling and assessment. Fifteen teams from eleven countries, representing industry, utilities, licensing organisations and research institutes, participated in the HF-RBE. The HF-RBE was organized around two study cases: (1) analysis of routine functional Test and Maintenance (T and M) procedures: with the aim of assessing the probability of test induced failures, the probability of failures to remain unrevealed and the potential to initiate transients because of errors performed in the test; (2) analysis of human actions during an operational transient: with the aim of assessing the probability that the operators will correctly diagnose the malfunctions and take proper corrective action. This report contains the final summary reports produced by the participants in the exercise

  16. Unity power factor switching regulator

    Science.gov (United States)

    Rippel, Wally E. (Inventor)

    1983-01-01

    A single or multiphase boost chopper regulator operating with unity power factor, for use such as to charge a battery is comprised of a power section for converting single or multiphase line energy into recharge energy including a rectifier (10), one inductor (L.sub.1) and one chopper (Q.sub.1) for each chopper phase for presenting a load (battery) with a current output, and duty cycle control means (16) for each chopper to control the average inductor current over each period of the chopper, and a sensing and control section including means (20) for sensing at least one load parameter, means (22) for producing a current command signal as a function of said parameter, means (26) for producing a feedback signal as a function of said current command signal and the average rectifier voltage output over each period of the chopper, means (28) for sensing current through said inductor, means (18) for comparing said feedback signal with said sensed current to produce, in response to a difference, a control signal applied to the duty cycle control means, whereby the average inductor current is proportionate to the average rectifier voltage output over each period of the chopper, and instantaneous line current is thereby maintained proportionate to the instantaneous line voltage, thus achieving a unity power factor. The boost chopper is comprised of a plurality of converters connected in parallel and operated in staggered phase. For optimal harmonic suppression, the duty cycles of the switching converters are evenly spaced, and by negative coupling between pairs 180.degree. out-of-phase, peak currents through the switches can be reduced while reducing the inductor size and mass.

  17. Etiological factors of psoas abscesses

    Directory of Open Access Journals (Sweden)

    Mehmet Nuri Bodakçi

    2014-03-01

    Full Text Available Objective: Psoas abscess (PA is a rare infection disease, which is difficult to diagnose. In the present study, we aimed to evaluate etiological factors and treatment results of patients with PA. Methods: Files of 20 patients who were diagnosed as PA between December 2006 and January 2013, were retrospectively analyzed. Patient’s whose data were entirely reached and diagnosed by Ultrasonography and/or Computed Tomography as an exact PA were included to the study. Results: The mean age of the 20 patients was 48.8 (range 17-82 year, and 6 of them were female and remaining were male. Psoas abscess were on the right side in 12 patients (60%, on the left side in seven patients (35%, and bilateral in one (5%. According to data records four patients had Diabetes Mellitus (20%, two had Hypertension (10%, one had cerebrovascular disease (5%, one had tuberculosis (5%, one had hyperthyroidism (5%, one had mental retardation (5%, and one had paraplegia (5%. Six case (30% were diagnosed as a primary psoas abscess (pPA, sPA and remaining (n=14, %70 were diagnosed as secondary. Percutaneous drainage was performed to 13 patients (65% and exploration was performed to three patients (15% as a treatment modality. Remaining four patients (20% were followed by medical treatment. Conclusion: Psoas abscess is rare and have variable and non-specific clinical characteristic, which may lead to difficulty in diagnosis. In developed and developing countries, it has been reported that the most common causes of sPA are Pott's disease, and Crohn's disease, also it should be taken into account that open surgery and urinary tract stone disease can receive a significant portion of the etiological factors. J Clin Exp Invest 2014; 5 (1: 59-63

  18. [Time factors factors in radiotherapy. Introduction (author's transl)].

    Science.gov (United States)

    Dutreix, J

    1976-11-01

    The role of time factors, the fractioning and spread of irradiation, continue to occupy an important place in conference, symposia and meeting of radiotherapists and our own Society has followed this tradition by devoting to the subject this session of the Journées de Radiologie 1975. The problem is a constant feature of everyday clinical practise. Whilst the majority of radiotherapists are prudently attached to the traditional method of 5 sessions per week, they are frequently forced to change this rhythm for pathological reasons, the personal convenience of the patient or problems with apparatus. The association of transcutaneous and curietherapeutic irradiation adds new parameters : the rate of the curie-therapy, the relative contribution of the 2 methods of irradiation, their sequence and the interval which separates them. Poor results of radiotherapy in certain situations indicates the possible value of determining whether other methods of the distribution per session and in time might lead to an improvement. Under these numerous circumstances, one is led to compare different forms of irradiation and to assess their possible biological differences. Objective description of the type of irradiation may be limited to the contents of the treatment sheet. However this does not easily express the biological quantity of the irradiation. As soon as the differences between two types of irradiation involves two parameters, they can no longer be effectively compared. The usefulness of a single figure to express the biological value of irradiation is obvious. With this aim, Cohen proposes calculation of levels of cell survival resulting from irradiation and extracts the parameters of this calculation from clinical results published in the literature. By similar analysis, Ellis has deduced the overall role of time factors which is expressed by the simple relation of the N.S.D., which has itself been at the origin of other expressions seeking to be more convenient and

  19. Expression of high mobility group box 1 in inflamed dental pulp and its chemotactic effect on dental pulp cells

    International Nuclear Information System (INIS)

    Highlights: • HMGB1 translocated from nucleus to cytoplasm during dental pulp inflammation. • HMGB1and its receptor RAGE were up-regulated in hDPCs under LPS stimulation. • HMGB1 enhanced hDPCs migration and induces cytoskeleton reorganization. • HMGB1 may play a critical role in dental pulp repair during inflamed state. - Abstract: High mobility group box 1 protein (HMGB1) is a chromatin protein which can be released extracellularly, eliciting a pro-inflammatory response and promoting tissue repair process. This study aimed to examine the expression and distribution of HMGB1 and its receptor RAGE in inflamed dental pulp tissues, and to assess its effects on proliferation, migration and cytoskeleton of cultured human dental pulp cells (DPCs). Our data demonstrated that cytoplasmic expression of HMGB1 was observed in inflamed pulp tissues, while HMGB1 expression was confined in the nuclei in healthy dental pulp. The mRNA expression of HMGB1 and RAGE were significantly increased in inflamed pulps. In in vitro cultured DPCs, expression of HMGB1 in both protein and mRNA level was up-regulated after treated with lipopolysaccharide (LPS). Exogenous HMGB1 enhanced DPCs migration in a dose-dependent manner and induced the reorganization of f-actin in DPCs. Our results suggests that HMGB1 are not only involved in the process of dental pulp inflammation, but also play an important role in the recruitment of dental pulp stem cells, promoting pulp repair and regeneration

  20. Expression of high mobility group box 1 in inflamed dental pulp and its chemotactic effect on dental pulp cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xufang, E-mail: xufang.zhang@student.qut.edu.au [Department of Operative Dentistry and Endodontics, Guanghua School of Stomatology, Guangdong Province Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou 510055 (China); Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD 4059 (Australia); Jiang, Hongwei, E-mail: jianghw@163.com [Department of Operative Dentistry and Endodontics, Guanghua School of Stomatology, Guangdong Province Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou 510055 (China); Gong, Qimei, E-mail: gongqmei@gmail.com [Department of Operative Dentistry and Endodontics, Guanghua School of Stomatology, Guangdong Province Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou 510055 (China); Fan, Chen, E-mail: c3.fan@student.qut.edu.au [Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD 4059 (Australia); Huang, Yihua, E-mail: enu0701@163.com [Department of Operative Dentistry and Endodontics, Guanghua School of Stomatology, Guangdong Province Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou 510055 (China); Ling, Junqi, E-mail: lingjq@mail.sysu.edu.cn [Department of Operative Dentistry and Endodontics, Guanghua School of Stomatology, Guangdong Province Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou 510055 (China)

    2014-08-08

    Highlights: • HMGB1 translocated from nucleus to cytoplasm during dental pulp inflammation. • HMGB1and its receptor RAGE were up-regulated in hDPCs under LPS stimulation. • HMGB1 enhanced hDPCs migration and induces cytoskeleton reorganization. • HMGB1 may play a critical role in dental pulp repair during inflamed state. - Abstract: High mobility group box 1 protein (HMGB1) is a chromatin protein which can be released extracellularly, eliciting a pro-inflammatory response and promoting tissue repair process. This study aimed to examine the expression and distribution of HMGB1 and its receptor RAGE in inflamed dental pulp tissues, and to assess its effects on proliferation, migration and cytoskeleton of cultured human dental pulp cells (DPCs). Our data demonstrated that cytoplasmic expression of HMGB1 was observed in inflamed pulp tissues, while HMGB1 expression was confined in the nuclei in healthy dental pulp. The mRNA expression of HMGB1 and RAGE were significantly increased in inflamed pulps. In in vitro cultured DPCs, expression of HMGB1 in both protein and mRNA level was up-regulated after treated with lipopolysaccharide (LPS). Exogenous HMGB1 enhanced DPCs migration in a dose-dependent manner and induced the reorganization of f-actin in DPCs. Our results suggests that HMGB1 are not only involved in the process of dental pulp inflammation, but also play an important role in the recruitment of dental pulp stem cells, promoting pulp repair and regeneration.