WorldWideScience

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. 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.

  3. Decreased numbers of chemotactic factor receptors in chronic neutropenia with defective chemotaxis: spontaneous recovery from the neutrophil abnormalities during early childhood

    International Nuclear Information System (INIS)

    Childhood chronic neutropenia with decreased numbers of chemotactic factor receptors as well as defective chemotaxis was first demonstrated in an 8-month-old girl. Chemotactic factor receptors on neutrophils were assayed using tritiated N-formyl-methionyl-leucyl-phenylalanine (3H-FMLP). The patient's neutrophils had decreased numbers of the receptors: numbers of the receptors were 20,000 (less than 3 SD) as compared with those of control cells of 52,000 +/- 6000 (mean +/- SD) (n = 10). The neutropenia disappeared spontaneously by 28 months of age parallel with the improvement of chemotaxis and increase in numbers of chemotactic factor receptors. These results demonstrate a transient decrease of neutrophil chemotactic factor receptors as one of the pathophysiological bases of a transient defect of neutrophil chemotaxis in this disorder

  4. Amplification of the spleen macrophage population in malaria: possible role of a factor chemotactic for blood mononuclear cells

    International Nuclear Information System (INIS)

    The mechanism of amplification of the splenic macrophages' population was investigated using mice infected with malaria as a model of an obligate intravascular infection. It was observed that these macrophages derived from blood monocytes rather than by local proliferation in the spleen. A factor, chemotactic for blood mononuclear cells, was present in spleen cells shortly after infection and preceded detectable increases in spleen macrophage number by 48 hours. This factor, in concert with spleen derived macrophage migration inhibition factor, may be important in the amplification of splenic macrophage population in intravascular infections

  5. 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...

  6. 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.

  7. Prevalence and organ distribution of leukocyte chemotactic factor 2 amyloidosis (ALECT2) among decedents in New Mexico.

    Science.gov (United States)

    Larsen, Christopher P; Beggs, Marjorie L; Wilson, Jon D; Lathrop, Sarah L

    2016-06-01

    Leukocyte chemotactic factor 2 (LECT2) amyloidosis is one of the most recently described types of amyloidosis. Since its description, it has been found to be one the most common types of amyloidosis in large series of amyloid cases involving the kidney and liver in the United States, where it primarily affects patients of Hispanic ethnicity. We sought to investigate the prevalence of this disease among Hispanic adult decedents who had an autopsy performed at the New Mexico Office of the Medical Investigator and determine the organ distribution of amyloid deposition. LECT2 amyloid deposits were identified within the kidney in 3.1% of Hispanic decedents. It was consistently deposited in the liver, spleen, adrenals, and lungs but did not involve the myocardium or brain. LECT2 amyloidosis is likely not rare among Hispanics in the Southwest United States and could represent an important but under-recognized etiology of chronic kidney disease in this population. PMID:26912093

  8. 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

  9. 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

  10. 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...

  11. Chemotactic Behavior of Azotobacter vinelandii

    OpenAIRE

    Haneline, Stephen; Connelly, Carla J.; Melton, Thoyd

    1991-01-01

    Chemotaxis was exhibited by Azotobacter vinelandii motile cells. Exposure of cells to sudden increases in attractant concentration suppressed the frequency of tumbling and resulted in smooth swimming. Cells responded chemotactically to a chemical gradient produced during metabolism. Motility occurred over a temperature range of 25 to 37°C with an optimum pH range of between pH 7.0 and 8.0. The average speed of motile cells was determined to be 74 μm/s or 37 body lengths per s. The speed of ce...

  12. 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.

  13. Hydrodynamical random walker with chemotactic memory

    OpenAIRE

    Mohammady, H.; Esckandariun, B.; Najafi, A.

    2014-01-01

    A three-dimensional hydrodynamical model for a micro random walker is combined with the idea of chemotactic signaling network of E. coli. Diffusion exponents, orientational correlation functions and their dependence on the geometrical and dynamical parameters of the system are analyzed numerically. Because of the chemotactic memory, the walker shows superdiffusing displacements in all directions with the largest diffusion exponent for a direction along the food gradient. Mean square displacem...

  14. 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

  15. Rapid intracellular calcium changes in U937 monocyte cell line: transient increases in response to platelet-activating factor and chemotactic peptide but not interferon-gamma or lipopolysaccharide.

    Science.gov (United States)

    Maudsley, D J; Morris, A G

    1987-06-01

    The dye fura-2, a potentially more sensitive successor to quin2 for measuring intracellular free calcium ion concentrations [(Ca2+]i), has been applied here to investigate the possible involvement of early changes in [Ca2+]i in the stimulation of the human monocyte-macrophage-like cell line U937. The calcium ionophores A23187 and ionomycin, known pharmacological stimuli for macrophages, were found to cause sharp rises in [Ca2+]i as expected. Responses analogous to those reported for a murine macrophage cell (J774) were obtained on stimulation of U937 cells with ATP which caused rapid, but transient, increases in [Ca2+]i (from resting levels of about 70 nM to peaks of about 200 mM). In addition to ATP, several agents known to activate macrophages were used as stimuli. In particular, platelet-activating factor (PAF; 1-0-alkyl-2-acetyl-sn-glycero-3-phosphocholine) was found to cause rapid, but transient, increases in [Ca2+]i (from resting levels of about 70 nM to peaks of about 400 nM) even at concentrations as low as 10(-10) M. This contrasts with responses to ATP that were markedly reduced at 10(-6) M compared with 10(-5) M or above, suggesting that PAF is a highly potent stimulus for intracellular calcium mobilization in macrophages. Similar responses were obtained with chemotactic peptide (N-formyl-methionyl-leucyl-phenylalanine). On the other hand, two agents known to be potent activators of macrophages, interferon gamma and lipopolysaccharide, had no rapid effect on [Ca2+]i. This may reflect differences in the kinetics of signal-response coupling or alternatively a different mechanism of action by-passing the need for rapid elevation of [Ca2+]i. PMID:3110054

  16. 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...

  17. 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.

  18. 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...

  19. Psoriasin: a novel chemotactic protein

    DEFF Research Database (Denmark)

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

    1996-01-01

    Inflammatory skin disorders such as psoriasis show a preferential epidermal infiltration of neutrophils and T lymphocytes. This observation raises a question as to which factors determine the appearance and composition of leukocyte tissue infiltrations. Previously, we described a low molecular ma...

  20. 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.

  1. 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.

  2. A chemotactic inhibitor in synovial fluid.

    Science.gov (United States)

    Matzner, Y; Partridge, R E; Babior, B M

    1983-01-01

    Synovial fluid was found to contain an inhibitor of neutrophil chemotaxis. The activity of this inhibitor was masked in native synovial fluid, but could be detected in fluid in which complement had been deactivated by mild heating. The inhibitor was most effective against the chemotactic activity of zymosan-activated serum (C5ades arg). It had little effect when N-formyl-methionyl-leucyl-phenylalanine served as chemoattractant. Inhibition was not the result of a direct effect on the neutrophils, since incubation of cells with synovial fluid did not alter their chemotactic response. The inhibitory activity was destroyed by boiling the synovial fluid or treating it with trypsin, suggesting that it is a protein (or proteins); it was not affected by hyaluronidase treatment. Gel filtration revealed that the inhibitor was present in native as well as decomplemented synovial fluid, and that its molecular weight was in the vicinity of 25,000. It is proposed that this inhibitory activity plays a role in the regulation of the inflammatory response in joints. PMID:6840801

  3. 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...

  4. 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.

  5. Neutrophil Chemotactic Activities In Bronchoalveolar Lavage Fluid From Patients with Bronchial Asthma

    OpenAIRE

    Park, Choon Sik; Cho, Seung Woo; Lee, Sei Young; Park, Tae Eung; Jeong, Seung Whan; Lee, Sang Moo; Kim, Hyeon Tae; Uh, Sootaek; Kim, Young Hoon

    1995-01-01

    Objectives To elucidate the presence of neutrophil chemotactic factor (NCF) and characterize them in the bronchial trees of symptomatic patients with bronchial asthma. Methods Bronchoalveolar lavage (BAL) fluids were concentrated by ultrafiltration. Differential counts of BAL cells was performed upto 500 cells on the cytocentrifuge-prepared slides. NCF activities in concentrated BAL fluids were measured by using microchemotactic chamber. These NCF activities were characterized by heat-stabili...

  6. Sensitivity of the rate of nutrient uptake by chemotactic bacteria to physical and biological parameters in a turbulent environment.

    Science.gov (United States)

    Watteaux, Romain; Stocker, Roman; Taylor, John R

    2015-12-21

    In this study, we use direct numerical simulations (DNS) to investigate the response of chemotactic bacteria to an isolated patch of chemoattractant in a turbulent environment. Previous work has shown that by stirring nutrients that are chemoattractants into a network of thin, elongated filaments, turbulence directly influences the rate at which chemotactic bacteria consume nutrients. However, the quantitative outcome of this process is influenced by a host of physical and biological factors, and many of these remain unexplored. Here, we analyse the sensitivity of nutrient uptake by chemotactic bacteria on a wide range of physical and biological parameters using a series of controlled DNS. Starting with uniformly distributed populations of motile and non-motile bacteria in a fully developed homogeneous, isotropic turbulent flow, we inject a patch of dissolved nutrients. We then assess the chemotactic advantage, defined as the difference between the nutrients consumed by motile and non-motile bacteria over the lifetime of the patch. We find that the chemotaxis can enhance the total uptake rate by a factor of 1.6 and allows the population of chemotactic bacteria to absorb nutrients 2.2 times faster than non-motile bacteria Results show that chemotactic bacteria are subject to a trade-off between swimming to leave regions devoid of nutrients and, once a nutrient gradient is detected, staying in regions of large nutrient concentration. These findings could help explain how the physical characteristics of turbulent marine ecosystems influence the optimal biological traits of bacteria through the competition for limited resources. PMID:26392215

  7. Bacterial chemotactic oligopeptides and the intestinal mucosal barrier

    International Nuclear Information System (INIS)

    Intestinal absorption and enterohepatic circulation of N-formyl-methionyl-leucyl-125I-tyrosine, a bioactive synthetic analog of the bacterial chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine has been investigated in the rat. In ileum and proximal and distal colon, dithiothreitol, which increases mucosal permeability, increased peptide absorption and biliary recovery fourfold, 70-fold, and 20-fold over control values, respectively. When dithiothreitol was combined with d-l-benzyl succinate, a potent inhibitor of intestinal carboxypeptidase, absorption and biliary recovery from ileal loops increased markedly to 40-fold over control, whereas there was no further increase in absorption from colon loops. There was a strong correlation between biliary N-formyl-methionyl-leucyl-125I-tyrosine recovery and intestinal absorption of 51Cr-ethylenediaminetetraacetate, a marker of passive mucosal permeability (r = 0.97). We conclude that in the ileum both enzymic degradation and restricted mucosal permeability contribute to the intestinal barrier to luminal bacterial formyl oligopeptides. In the colon, however, enzymic mechanisms are less active and restricted mucosal permeability is the major factor. Abnormalities of the intestinal mucosal barrier to proinflammatory bacterial peptides could play a role in inflammatory disorders of the gut

  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. Chemotactic Behavior of Pathogenic and Nonpathogenic Leptospira Species

    OpenAIRE

    Lambert, Ambroise; Takahashi, Naoko; Charon, Nyles W.; Picardeau, Mathieu

    2012-01-01

    We have developed a capillary tube assay in combination with real-time PCR to quantitate the number of chemoattracted Leptospira cells. We identified Tween 80, glucose, sucrose, and pyruvate as attractants for Leptospira cells; amino acids and vitamin B12 were found to be nonchemotactic or weakly chemotactic. This assay has the general applicability to further our understanding of leptospiral chemotaxis.

  10. 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)

  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. Adaptation and optimal chemotactic strategy for E. coli

    International Nuclear Information System (INIS)

    Extending the classic works of Berg and Purcell on the biophysics of bacterial chemotaxis, we find the optimal chemotactic strategy for the peritrichous bacterium E. coli in the high and low signal to noise ratio limits. The optimal strategy depends on properties of the environment and properties of the individual bacterium, and is therefore highly adaptive. We review experiments relevant to testing both the form of the proposed strategy and its adaptability, and propose extensions of them which could test the limits of the adaptability in this simplest sensory processing system. copyright 1998 The American Physical Society

  14. 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.

  15. 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

  16. 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

  17. 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.

  18. Effect of selective phosphodiesterase inhibitors on the rat eosinophil chemotactic response in vitro

    Directory of Open Access Journals (Sweden)

    Alves Alessandra C

    1997-01-01

    Full Text Available In the present study, we have performed a comparative analysis of the effect of selective inhibitors of phosphodiesterase (PDE type III, IV and V on eosinophil chemotaxis triggered by platelet activating factor (PAF and leukotriene B4 (LTB4 in vitro. The effect of the analogues N6-2'-O-dibutyryladenosine 3':5' cyclic monophosphate (Bt2 cyclic AMP and N2-2'-O- dibutyrylguanosine 3':5' cyclic monophosphate (Bt2 cyclic GMP has also been determined. The eosinophils were obtained from the peritoneal cavity of naive Wistar rats and purified in discontinuous Percoll gradients to 85-95% purity. We observed that pre-incubation of eosinophils with the PDE type IV inhibitor rolipram suppressed the chemotactic response triggered by PAF and LTB4, in association with an increase in the intracellular levels of cyclic AMP. In contrast, neither zaprinast (type V inhibitor nor type III inhibitors milrinone and SK&F 94836 affected the eosinophil migration. Only at the highest concentration tested did the analogue Bt2 cyclic AMP suppress the eosinophil chemotaxis, under conditions where Bt2 cyclic GMP was ineffective. We have concluded that inhibition of PDE IV, but not PDE III or V, was able to block the eosinophil chemotaxis in vitro, suggesting that the suppressive activity of selective PDE IV inhibitors on tissue eosinophil accumulation may, at least, be partially dependent on their ability to directly inhibit the eosinophil migration.

  19. Ca2+ spikes in the flagellum control chemotactic behavior of sperm.

    Science.gov (United States)

    Böhmer, Martin; Van, Qui; Weyand, Ingo; Hagen, Volker; Beyermann, Michael; Matsumoto, Midori; Hoshi, Motonori; Hildebrand, Eilo; Kaupp, Ulrich Benjamin

    2005-08-01

    The events that occur during chemotaxis of sperm are only partly known. As an essential step toward determining the underlying mechanism, we have recorded Ca2+ dynamics in swimming sperm of marine invertebrates. Stimulation of the sea urchin Arbacia punctulata by the chemoattractant or by intracellular cGMP evokes Ca2+ spikes in the flagellum. A Ca2+ spike elicits a turn in the trajectory followed by a period of straight swimming ('turn-and-run'). The train of Ca2+ spikes gives rise to repetitive loop-like movements. When sperm swim in a concentration gradient of the attractant, the Ca2+ spikes and the stimulus function are synchronized, suggesting that precise timing of Ca2+ spikes controls navigation. We identified the peptide asterosap as a chemotactic factor of the starfish Asterias amurensis. The Ca2+ spikes and swimming behavior of sperm from starfish and sea urchin are similar, implying that the signaling pathway of chemotaxis has been conserved for almost 500 million years. PMID:16001082

  20. The stability of a homogeneous suspension of chemotactic bacteria

    Science.gov (United States)

    Subramanian, G.; Koch, Donald L.; Fitzgibbon, Sean R.

    2011-04-01

    The linear stability of a homogeneous dilute suspension of chemotactic bacteria in a constant chemoattractant gradient is analyzed. The bacteria execute a run-and-tumble motion, typified by the species E. coli, wherein periods of smooth swimming (runs) are interrupted by abrupt uncorrelated changes in swimming direction (tumbles). Bacteria tumble less frequently when swimming toward regions of higher chemoattractant concentration, leading to a mean bacterial orientation and velocity in the base state. The stability of an unbounded suspension, both with and without a chemoattractant, is controlled by coupled long wavelength perturbations of the fluid velocity and bacterial orientation fields. In the former case, the most unstable perturbations have their wave vector oriented along the chemoattractant gradient. Chemotaxis reduces the critical bacteria concentration, for the onset of collective swimming, compared with that predicted by Subramanian and Koch ["Critical bacterial concentration for the onset of collective swimming," J. Fluid Mech. 632, 359 (2009)] in the absence of a chemoattractant. A part of this decrease may be attributed to the increase in the mean tumbling time in the presence of a chemoattractant gradient. A second destabilizing influence comes from the ability of the shearing motion, associated with a velocity perturbation in which the velocity and chemical gradients are aligned, to sweep prealigned bacteria into the local extensional quadrant thereby creating a stronger destabilizing active stress than in an initially isotropic suspension. The chemoattractant gradient also fundamentally alters the unstable spectrum for any finite wavenumber. In suspensions of bacteria that do not tumble, Saintillan and Shelley ["Instabilities and pattern formation in active particle suspensions: Kinetic theory and continuum simulations," Phys. Rev. Lett. 100, 178103 (2008); "Instabilities, pattern formation and mixing in active suspensions," Phys. Fluids 20

  1. 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.

  2. Nutrient exposure of chemotactic organisms in small-scale turbulent flows

    Energy Technology Data Exchange (ETDEWEB)

    Munoz-Garcia, Javier [Systems Biology Ireland and Grupo Interdisciplinar de Sistemas Complejos (GISC), University College Dublin, Belfield, Dublin 4 (Ireland); Neufeld, Zoltan [School of Mathematical Sciences and Complex and Adaptive Systems Laboratory, University College Dublin, Belfield, Dublin 4 (Ireland); Torney, Colin, E-mail: javiermunozgarcia@gmail.co [Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544 (United States)

    2010-10-15

    Micro-organisms living in a turbulent fluid environment often use directed motility to locate regions of higher than average nutrient concentrations. Here, we consider a simple continuum model for the distribution of such chemotactic particles when the particles and the chemoattractant are both advected by a turbulent flow. The influence of chemotactic sensitivity on the spatial distribution of the particles is characterized for different types of advected chemical fields. Using an effective diffusion approximation, we obtain an analytical expression for the nutrient exposure resulting from the chemotactic activity of the particles, generalizing previous results obtained for the case of phototaxis in flows. We show that the biological advantage of chemotaxis in such systems is determined by the spatial variability of the averaged chemoattractant field and the effective diffusivity of the turbulent flow.

  3. Neutrophil chemotactic activity in bronchoalveolar lavage fluid of patients with AIDS-associated Pneumocystis carinii pneumonia

    DEFF Research Database (Denmark)

    Benfield, T L; Kharazmi, A; Larsen, C G; Lundgren, J D

    1997-01-01

    been shown to confer a poor prognosis in PCP. We therefore investigated the potential of BAL fluid from 17 patients with PCP to induce neutrophil chemotaxis. BAL fluid from patients induced considerable neutrophil chemotactic activity compared to normal controls. Elevated levels of IL-8 were detected...... in patient samples as compared to controls. A specific anti-IL-8 antibody significantly reduced chemotactic activity of patient samples by more than 50%. In conclusion, IL-8 appears to be a significant participant of neutrophil chemotaxis in AIDS-associated PCP, and may participate in the recruitment...

  4. 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

  5. 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...

  6. 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.

  7. 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

  8. 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...

  9. Fluorine-18 labeled chemotactic peptides: A potential approach for the PET imaging of bacterial infection

    International Nuclear Information System (INIS)

    A potent chemotactic peptide, formyl-norleucyl-leucyl-phenylalanyl-norleucyl-tyrosyl-lysine was derivatized by reaction with N-succinimidyl 4-fluorobenzoate. This derivatized peptide bound to human polymorphonuclear leukocytes in vitro and exhibited biological activity in a superoxide production assay. Peptide labeling using N-succinimidyl 4-[18F]fluorobenzoate was accomplished in reasonable yields with 10-15 mCi of labeled peptide available per 100 Ci of [18F]fluoride. With the exception of the gastrointestinal tract, clearance of activity from tissues following injection of this peptide in normal mice was rapid. Although preliminary in nature, these results suggest that 18F-labeled chemotactic peptides should be investigated as potential agents for positron emission tomographic imaging of bacterial infections

  10. 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

  11. 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 ...

  12. 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...

  13. 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.

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

    OpenAIRE

    Sandeep Bisht; Piyush Pandey; Anchal Sood; Shivesh Sharma; Bisht, N. S.

    2010-01-01

    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 isolat...

  15. 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

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. Imaging focal sites of bacterial infection in rats with indium-111-labeled chemotactic peptide analogs

    International Nuclear Information System (INIS)

    Four DTPA-derivatized chemotactic peptide analogs: ForNleLFNleYK-DTPA (P1), ForMLFNH(CH2)6NH-DTPA (P2), ForNleLFK(NH2)-DTPA (P3), and ForNleLFK-DTPA (P4), were synthesized and evaluated for in vitro bioactivity and receptor binding. The peptides were radiolabeled with 111In by transchelation and their biodistribution determined in rats at 5, 30, 60 and 120 min after injection. Localization at sites of infection was determined by scintillation camera imaging in animals with deep-thigh infection due to Escherichia coli. Images were recorded from 5 min to 2 hr after injection. All peptides maintained biologic activity (EC50 for O2-production by human PMN's: 3-150 nM) and the ability to bind to the oligopeptide chemoattractant receptor on human PMN's (EC50 for binding: 7.5-50 nM); biologic activity and receptor binding were highly correlated (r = 0.99). For all the peptides, blood clearance was rapid (half-lives: 21.5, 33.1, 31.6, and 28.7 min for P1, P2, P3, and P4, respectively). Biodistributions of the individual peptides were similar with low levels of accumulation in the heart, lung, liver, spleen, and gastrointestinal tract. In the kidney, P1 had much greater accumulation than other organs. All peptides yielded high quality images of the infection sites within 1 hr of injection. This study demonstrates that 111In-labeled chemotactic peptide analogs were effective agents for the external imaging of focal sites of infection

  8. 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

  9. 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...

  10. Emerging morphologies in round bacterial colonies: comparing volumetric versus chemotactic expansion.

    Science.gov (United States)

    Giverso, Chiara; Verani, Marco; Ciarletta, Pasquale

    2016-06-01

    Biological experiments performed on living bacterial colonies have demonstrated the microbial capability to develop finger-like shapes and highly irregular contours, even starting from an homogeneous inoculum. In this work, we study from the continuum mechanics viewpoint the emergence of such branched morphologies in an initially circular colony expanding on the top of a Petri dish coated with agar. The bacterial colony expansion, based on either a source term, representing volumetric mitotic processes, or a nonconvective mass flux, describing chemotactic expansion, is modeled at the continuum scale. We demonstrate that the front of the colony is always linearly unstable, having similar dispersion curves to the ones characterizing branching instabilities. We also perform finite element simulations, which not only prove the emergence of branching, but also highlight dramatic differences between the two mechanisms of colony expansion in the nonlinear regime. Furthermore, the proposed combination of analytical and numerical analysis allowed studying the influence of different model parameters on the selection of specific patterns. A very good agreement has been found between the resulting simulations and the typical structures observed in biological assays. Finally, this work provides a new interpretation of the emergence of branched patterns in living aggregates, depicted as the results of a complex interplay among chemical, mechanical and size effects. PMID:26296713

  11. 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.

  12. Directional memory arises from long-lived cytoskeletal asymmetries in polarized chemotactic cells.

    Science.gov (United States)

    Prentice-Mott, Harrison V; Meroz, Yasmine; Carlson, Andreas; Levine, Michael A; Davidson, Michael W; Irimia, Daniel; Charras, Guillaume T; Mahadevan, L; Shah, Jagesh V

    2016-02-01

    Chemotaxis, the directional migration of cells in a chemical gradient, is robust to fluctuations associated with low chemical concentrations and dynamically changing gradients as well as high saturating chemical concentrations. Although a number of reports have identified cellular behavior consistent with a directional memory that could account for behavior in these complex environments, the quantitative and molecular details of such a memory process remain unknown. Using microfluidics to confine cellular motion to a 1D channel and control chemoattractant exposure, we observed directional memory in chemotactic neutrophil-like cells. We modeled this directional memory as a long-lived intracellular asymmetry that decays slower than observed membrane phospholipid signaling. Measurements of intracellular dynamics revealed that moesin at the cell rear is a long-lived element that when inhibited, results in a reduction of memory. Inhibition of ROCK (Rho-associated protein kinase), downstream of RhoA (Ras homolog gene family, member A), stabilized moesin and directional memory while depolymerization of microtubules (MTs) disoriented moesin deposition and also reduced directional memory. Our study reveals that long-lived polarized cytoskeletal structures, specifically moesin, actomyosin, and MTs, provide a directional memory in neutrophil-like cells even as they respond on short time scales to external chemical cues. PMID:26764383

  13. Oxidized low-density lipoproteins may induce expression of monocyte chemotactic protein-3 in atherosclerotic plaques

    International Nuclear Information System (INIS)

    Genes induced or suppressed by oxidized low-density lipoproteins (oxLDL) in human monocytic THP-1 cells were searched using the differential display reverse transcriptase polymerase chain reaction. One of the differentially expressed (up-regulated) cDNA fragments was found to contain sequences corresponding to monocyte chemotactic protein-3 (MCP-3). The stimulatory effect of the oxLDL on the expression of MCP-3 mRNA was both time- and dose-dependent. Treatment with GF109203X and genistein, inhibitors of protein kinase C and tyrosine kinase, respectively, had no effect on the induction of MCP-3 mRNA by oxLDL, while treatment with cycloheximide inhibited the induction. The induction was reproduced by the lipid components in oxLDL such as 9-HODE and 13-HODE, which are known to activate the peroxisome proliferator-activated receptor γ (PPARγ). Introduction of an endogenous PPARγ ligand, 15d-PGJ2, in the culture of THP-1 cells resulted in the induction of MCP-3 gene expression. Furthermore, analyses of human atherosclerotic plaques revealed that the expressional pattern of MCP-3 in the regions of neointimal and necrotic core overlapped with that of PPARγ. These results suggest that oxLDL delivers its signal for MCP-3 expression via PPARγ, which may be further related to the atherogenesis

  14. 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.

  15. 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

  16. 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

  17. 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

  18. Functional characterization of ferret CCL20 and CCR6 and identification of chemotactic inhibitors.

    Science.gov (United States)

    Qin, Shulin; Klamar, Cynthia R; Fallert Junecko, Beth A; Craigo, Jodi; Fuller, Deborah H; Reinhart, Todd A

    2013-03-01

    CCL20 is currently the only known chemokine ligand for the receptor CCR6, and is a mucosal chemokine involved in normal and pathological immune responses. Although nucleotide sequence data are available for ccl20 and ccr6 sequences from multiple species, the ferret ccl20 and ccr6 sequences have not been determined. To increase our understanding of immune function in ferret models of infection and vaccination, we have used RT-PCR to obtain the ferret ccl20 and ccr6 cDNA sequences and functionally characterize the encoded proteins. The open reading frames of both genes were highly conserved across species and mostly closely related to canine sequences. For functional analyses, single cell clones expressing ferret CCR6 were generated, a ferret CCL20/mouse IgG(2a) fusion protein (fCCL20-mIgG(2a)) was produced, and fCCL20 was chemically synthesized. Cell clones expressing ferret CCR6 responded chemotactically to fCCL20-mIgG2a fusion protein and synthetic ferret CCL20. Chemotaxis inhibition studies identified the polyphenol epigallocatechin-3-gallate and the murine γ-herpesvirus 68 M3 protein as inhibitors of fCCL20. Surface plasmon resonance studies revealed that EGCG bound directly to fCCL20. These results provide molecular characterization of previously unreported ferret immune gene sequences and for the first time identify a broad-spectrum small molecule inhibitor of CCL20 and reveal CCL20 as a target for the herpesviral M3 protein. PMID:23360828

  19. 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

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

    Directory of Open Access Journals (Sweden)

    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.

  1. 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.

  2. 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

  3. 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

  4. 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

  5. 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. PMID:24427941

  6. Beneficial effects of the naturally occurring flavonoid silibinin on the prostate cancer microenvironment: role of monocyte chemotactic protein-1 and immune cell recruitment.

    Science.gov (United States)

    Ting, Harold; Deep, Gagan; Kumar, Sushil; Jain, Anil K; Agarwal, Chapla; Agarwal, Rajesh

    2016-06-01

    Tumor microenvironment plays an essential role in prostate carcinogenesis and offers novel opportunities to prevent and treat prostate cancer (PCA). Here, we investigated the ability of cancer-associated fibroblasts (CAFs) to promote PCA progression, and silibinin efficacy to target this response. We collected conditioned media from CAFs treated with vehicle or silibinin, and labeled as control conditioned media (CCM) or silibinin-treatment conditioned media (SBCM), respectively. Next, we characterized the effect of CCM and SBCM treatment in several PCA cell lines (RWPE-1, WPE-1 NA-22, WPE-1 NB-14 and PC3). Result showed that compared with SBCM, CCM significantly reduces E-cadherin expression and increases invasiveness and clonogenicity in PCA cells. Further molecular studies identified monocyte chemotactic protein-1 (MCP-1) as the key component of CCM that promotes PCA invasiveness, whereas silibinin treatment strongly reduced MCP-1 expression in CAFs by inhibiting the DNA-binding activity of MCP-1 transcriptional regulators-nuclear factor-kappaB and AP-1. In vivo, silibinin feeding (200mg/kg body weight) strongly reduced TRAMPC1 allografts growth (by 68%) in syngeneic C57Bl/6 mice. TRAMPC1 tumor analysis showed that silibinin reduced MCP-1 and CAFs' biomarkers (fibroblast activation protein, α-smooth muscle actin, transforming growth factor beta 2, vimentin etc.) and significantly modulated the recruitment of immune cells in the tumor microenvironment. Similar inhibitory effects of silibinin on MCP-1 and immune cells recruitment were also observed in TRAMP PCA tissues with reported silibinin efficacy. Overall, our data suggest that silibinin can target CAF-mediated invasiveness in PCA by inhibiting MCP-1 secretion. This, in turn, was associated with a reduction in immune cell recruitment in vivo along with a marked reduction in tumor growth. PMID:27207648

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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...

  12. 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...

  13. 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

  14. Characterization of the formyl peptide chemotactic receptor appearing at the phagocytic cell surface after exposure to phorbol myristate acetate

    International Nuclear Information System (INIS)

    The biochemistry and subcellular source of new formyl peptide chemotactic receptor appearing at the human neutrophil and differentiated HL-60 (d-HL-60) cell surface after stimulation with phorbol myristate acetate (PMA) were examined. Formyl peptide receptor was analyzed by affinity labeling with formyl-norleu-leu-phe-norleu- [125I]iodotyr-lys and ethylene glycol bis(succinimidyl succinate) followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and densitometric analysis of autoradiographs. PMA, a specific granule secretagogue, increases affinity labeling of formyl peptide receptors on the neutrophil surface by 100%, and on d-HL-60, which lack specific granule markers, by 20%. Papain treatment markedly reduces surface labeling of formyl peptide receptor in both neutrophils and d-HL-60, and results in the appearance of a lower m.w. membrane-bound receptor fragment. PMA stimulation of papain-treated cells increases uncleaved surface receptor on neutrophils by 400%, and on D-HL-60 by only 45%. This newly appearing receptor is the same apparent m.w. (55,000 to 75,000 for neutrophils; 62,000 to 80,000 for d-HL-60) and yields the same papain cleavage product as receptor on the surface of unstimulated cells. These observations suggest that specific granule membranes contain large amounts of formyl peptide receptor, which is biochemically identical to that found on the cell surface and can be mobilized to the cell surface with appropriate stimulation

  15. 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.

  16. 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)

  17. Single Cell Chemotactic Responses of Helicobacter pylori to Urea in a Microfluidic Chip

    OpenAIRE

    Xuan Weng; Suresh Neethirajan; Adam Vogt

    2016-01-01

    Helicobacter pylori is a spiral-shaped bacterium that grows in the human digestive tract; it infects ~50% of the global population. H. pylori induce inflammation, gastroenteritis, and ulcers, which is associated with significant morbidity and may be linked to stomach cancer in certain individuals. Motility is an essential virulence factor for H. pylori, allowing it to migrate toward and invade the epithelial lining of the stomach to shelter it from the harsh environment of the stomach. H. pyl...

  18. 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...

  19. 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.

  20. 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

  1. A hybrid computational model to predict chemotactic guidance of growth cones

    Science.gov (United States)

    Roccasalvo, Iolanda Morana; Micera, Silvestro; Sergi, Pier Nicola

    2015-06-01

    The overall strategy used by growing axons to find their correct paths during the nervous system development is not yet completely understood. Indeed, some emergent and counterintuitive phenomena were recently described during axon pathfinding in presence of chemical gradients. Here, a novel computational model is presented together with its ability to reproduce both regular and counterintuitive axonal behaviours. In this model, the key role of intracellular calcium was phenomenologically modelled through a non standard Gierer-Meinhardt system, as a crucial factor influencing the growth cone behaviour both in regular and complex conditions. This model was able to explicitly reproduce neuritic paths accounting for the complex interplay between extracellular and intracellular environments, through the sensing capability of the growth cone. The reliability of this approach was proven by using quantitative metrics, numerically supporting the similarity between in silico and biological results in regular conditions (control and attraction). Finally, the model was able to qualitatively predict emergent and counterintuitive phenomena resulting from complex boundary conditions.

  2. 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.

  3. 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

  4. 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 ...

  5. 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.

  6. 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...

  7. 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.

  8. 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.

  9. 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)

  10. 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

  11. Mouse macrophages completely lacking Rho (RhoA, RhoB and RhoC) have severe lamellipodial retraction defects, but robust chemotactic navigation and increased motility

    DEFF Research Database (Denmark)

    Koenigs, Volker; Jennings, Richard; Vogl, Thomas;

    2014-01-01

    RhoA is thought to be essential for coordination of the membrane protrusions and retractions required for immune cell motility and directed migration. Whether the subfamily of Rho (Ras homolog) GTPases (RhoA, RhoB and RhoC) is actually required for the directed migration of primary cells is...... dKO cells, which developed extremely elongated tails. Surprisingly, velocity (of the cell body) was increased, while chemotactic efficiency was preserved, compared to wild-type (WT) macrophages. Randomly migrating RhoA/RhoB dKO macrophages exhibited multiple small protrusions and developed large...... involved in pulling up the rear end and resorbing lamellipodial membrane protrusions. Macrophages lacking Rho proteins migrate faster in vitro, which, in the case of the peritoneum, translates to more rapid in vivo monocyte/macrophage recruitment....

  12. Direct and indirect radioiodination of protein: comparative study of chemotactic peptide labeling; Radioiodacao de proteina por via direta e indireta: estudo comparativo da marcacao de peptideo quimiotatico

    Energy Technology Data Exchange (ETDEWEB)

    Lavinas, Tatiana

    2004-07-01

    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-[{sup 123}l/{sup 131}l] 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

  13. Quantum dots induced monocyte chemotactic protein-1 expression via MyD88-dependent Toll-like receptor signaling pathways in macrophages

    International Nuclear Information System (INIS)

    Quantum dots (QDs) are nano-sized semiconductors. Previously, intratracheal instillation of QD705s induces persistent inflammation in mouse lungs. In our present study, QD705-COOH and QD705-PEG activated NF-κB and increased monocyte chemotactic protein-1 (MCP-1) expression in macrophages RAW264.7 via MyD88 dependent Toll-like receptor (TLR) signaling pathways. MyD88 is an adapter protein for most TLRs to activate NF-κB. Silencing expression of MyD88 or p65 with siRNA or co-treatment with a NF-κB inhibitor tremendously abolished QD705s-induced NF-κB activity and MCP-1 expression. The involved TLRs might locate either on the cell surface or inside of cells. Co-treatment with a TLR4 inhibitor completely prevented MCP-1 induction by QD705-PEG. Nevertheless, QD705-COOH readily entered cells, and co-treatment with either inhibitors of endocytosis or intracellular TLRs prevented MCP-1 induction. These findings indicate that, depending on their surface modification, OD705s activate MyD88 dependent-TLRs at the surface or inside of the cells, which is an important mechanism for nanoparticles-induced inflammatory responses. But other MyD88-independent pathways may also involve in these responses

  14. 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

  15. 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

  16. 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.

  17. Imaging macrophages and the apoptosis of granulocytes in a rodent model of subacute and chronic abscesses with radiolabeled monocyte chemotactic peptide-1 and annexin V

    Energy Technology Data Exchange (ETDEWEB)

    Blankenberg, F.G. [Div.of Pediatric Radiology, Lucile Salter Packard Children' s Hospital, Stanford, CA (United States); Tait, J.F. [Dept. of Laboratory Medicine, Univ. of Washington, Seattle (United States); Blankenberg, T.A. [Redding Pathology Labs., Redding, CA (United States); Post, A.M.; Strauss, H.W. [Div. of Nuclear Medicine, Dept. of Radiology, Stanford, CA (United States)

    2001-09-01

    Monocytes/macrophages (M{phi}s), the predominant cell types in subacute and chronic inflammation, are attracted to and activated by monocyte chemotactic peptide-1 (MCP-1). M{phi}s promote the resolution of inflammation through the induction of apoptosis and phagocytosis of senescent (spent) and bystander (superfluous) granulocytes. We wished to determine whether MCP-1, which selectively binds to M{phi}s, could be used to image subacute and chronic inflammation. We also sought to image granulocyte apoptosis within these lesions with technetium-99m labeled annexin V, a marker of apoptotic cells. Sterile inflammation was induced in 45 12-week-old male Sprague-Dawley rats by deep intramuscular injection of turpentine into the right thigh. Groups of four to six animals were then imaged 1 h after tail vein injection of 37-148 MBq (1-4 mCi) of {sup 99m}Tc-labeled MCP-1 or annexin V 1-14 days after turpentine treatment. Image analysis showed significantly greater activity of both MCP-1 and annexin V in inflamed thighs than in control thighs (165%-290% and 188%-313%, respectively; P<0.01) on days 1-5 after turpentine injection. Dual autoradiography in animals co-injected with iodine-125 labeled bovine serum albumin on days 1 and 4 showed specific location of MCP-1 to infiltrating M{phi}s while annexin V localized to focal zones of apoptosis within granulocytic infiltrates adjacent to abscess cavities. Scintillation well counting on day 5 demonstrated significantly higher (P<0.005) ratios of abscess to control thigh specific activities for MCP-1 (5.83{+-}2.17) and annexin V (9.24{+-}2.8) as compared to {sup 125}I-labeled bovine serum albumin (3.11{+-}0.65). No significant increases in uptake were noted at imaging or ex vivo analyses on days 13 and 14, when lesions were predominately fibrotic. It is concluded that {sup 99m}Tc-labeled MCP-1 and {sup 99m}Tc-labeled annexin V both localize in zones of subacute inflammation, reflecting the density of M{phi}s and the incidence of

  18. Hypoxia-Induced Mitogenic Factor (HIMF/FIZZ1/RELMα) Recruits Bone Marrow-Derived Cells to the Murine Pulmonary Vasculature

    OpenAIRE

    Angelini, Daniel J.; Su, Qingning; Kolosova, Irina A.; Fan, Chunling; Skinner, John T.; Yamaji-Kegan, Kazuyo; Collector, Michael; Sharkis, Saul J.; Johns, Roger A.

    2010-01-01

    Background Pulmonary hypertension (PH) is a disease of multiple etiologies with several common pathological features, including inflammation and pulmonary vascular remodeling. Recent evidence has suggested a potential role for the recruitment of bone marrow-derived (BMD) progenitor cells to this remodeling process. We recently demonstrated that hypoxia-induced mitogenic factor (HIMF/FIZZ1/RELMα) is chemotactic to murine bone marrow cells in vitro and involved in pulmonary vascular remodeling ...

  19. Attachment of smooth muscle cells to collagen and their migration toward platelet-derived growth factor.

    OpenAIRE

    Grotendorst, G R; Seppä, H E; Kleinman, H K; Martin, G R

    1981-01-01

    Smooth muscle cells use fibronectin to bind to type I and type III collagens but bind to type V collagen by a trypsin-resistant intrinsic glycoconjugate. The binding site on type V collagen is located in the alpha A chain. By using collagen-coated filters in a modified Boyden chamber assay for chemotaxis, it was observed that the platelet-derived growth factor was chemotactic for smooth muscle cells but that several other growth factors were inactive. We suggest that the migration of smooth m...

  20. The alpha hemolysin of Escherichia Coli power the metabolism oxidative of neutrophils human beings in response to the peptide chemotactic FMLP: comparison with the ionophore of calcium A23187

    International Nuclear Information System (INIS)

    The calcium ionophore ionomycin primes polymorphonuclear leukocytes (PMN) for increased superoxide production upon stimulation with the chemotactic peptide FMLP (Helman Finkel, T. et al J Biol Chem 1987; 262: 12589-12596) In this investigation we assessed the effect of PMN priming with either alpha hemolysin (AH) or the calcium ionophore A23187, both of which increase intracellular calcium, on the oxidative metabolism of PMN (as measured by chemiluminescence) in response to secondary stimulation with FMLP. Both A23187 and AH priming increased, the luminol-enhanced chemiluminescence in response to secondary stimulation with FMLP, indicating overstimulation of PMLP oxidative metabolism. Additional experiments using lucigenin as chemiluminescence enhancer showed that A23187, but not AH priming of PMN, increased superoxide release in a manner similar to that reported for ionomycin. These results are discussed in reference to infectious processes involving hemolytic E. coli (Author)

  1. 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

  2. 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

  3. Adiponectin-induced secretion of interleukin-6 (IL-6, monocyte chemotactic protein-1 (MCP-1, CCL2 and interleukin-8 (IL-8, CXCL8 is impaired in monocytes from patients with type I diabetes

    Directory of Open Access Journals (Sweden)

    Maier Kevin

    2006-08-01

    Full Text Available Abstract Background Systemic adiponectin is reduced in patients with cardiovascular disease (CVD and low adiponectin may contribute to the pathogenesis of atherosclerosis. However, circulating adiponectin is elevated in type 1 diabetes (T1D patients, who have also a higher incidence to develop CVD. Because monocytes play an important role in atherosclerosis, we analysed the influence of adiponectin on cytokine and chemokine release in monocytes from T1D patients and controls. Methods Systemic adiponectin was determined in the plasma and the high-molecular weight (HMW form of adiponectin was analysed by immunoblot. Monocytes were isolated from T1D patients and controls and the adiponectin-stimulated release of interleukin-6 (IL-6, monocyte chemotactic protein-1 (MCP-1, CCL2 and interleukin-8 (IL-8, CXCL8 was analysed. Results Systemic adiponectin was higher in T1D patients. Immunoblot analysis of the plasma indicate abundance of HMW adiponectin in T1D patients and controls. IL-6, CCL2 and CXCL8 secretion in response to adiponectin were found induced in monocytes from controls whereas only IL-6 was upregulated in T1D cells. The induction of IL-6 by adiponectin was abrogated by an inhibitor of the NFκB pathway. Conclusion These data indicate that adiponectin-mediated induction of IL-6, CCL2 and CXCL8 is disturbed in monocytes from T1D patients and therefore elevated systemic adiponectin in T1D patients may be less protective when compared to controls.

  4. 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

  5. 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

  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; Jing, C; Millner, A; Jensen, B; Madsen, H O; Ryder, L P; Svejgaard, A; Malling, H J; Skov, P S; Poulsen, Lars K.

    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...... Mig-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....... (Blood. 2000;96:1230-1238)...

  7. 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.

  8. 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.

  9. Small-Nucleic-Acid-Based Therapeutic Strategy Targeting the Transcription Factors Regulating the Vascular Inflammation, Remodeling and Fibrosis in Atherosclerosis

    Directory of Open Access Journals (Sweden)

    Sung Won Youn

    2015-05-01

    Full Text Available Atherosclerosis arises when injury to the arterial wall induces an inflammatory cascade that is sustained by a complex network of cytokines, together with accumulation of lipids and fibrous material. Inflammatory cascades involve leukocyte adherence and chemotaxis, which are coordinated by the local secretion of adhesion molecules, chemotactic factors, and cytokines. Transcription factors are critical to the integration of the various steps of the cascade response to mediators of vascular injury, and are induced in a stimulus-dependent and cell-type-specific manner. Several small-nucleic-acid-based therapeutic strategies have recently been developed to target transcription factors: antisense oligodeoxynucleotides, RNA interference, microRNA, and decoy oligodeoxynucleotides. The aim of this review was to provide an overview of these particular targeted therapeutic strategies, toward regulation of the vascular inflammation, remodeling and fibrosis associated with atherosclerosis.

  10. 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

  11. Innate Immunity Derived Factors as External Modulators of the CXCL12 - CXCR4 Axis and Their Role in Stem Cell Homing and Mobilization

    Directory of Open Access Journals (Sweden)

    Mariusz Z. Ratajczak, Karol Serwin, Gabriela Schneider

    2013-01-01

    Full Text Available The α-chemokine CXCL12 (stromal derived factor-1; SDF-1 and its corresponding GαI protein-coupled CXCR4 receptor axis play an important role in retention of hematopoietic stem progenitor cells (HSPCs in bone marrow (BM stem cell niches. CXCL12 has also been identified as a strong chemoattractant for HSPCs and implicated both in homing of HSPCs to BM after transplantation and in egress of these cells from BM into peripheral blood (PB. However, since CXCL12, as a peptide, is highly susceptible to degradation by proteolytic enzymes, its real biological availability in biological fluids may be somewhat limited. In this review, we will present data demonstrating that the CXCL12-CXCR4 axis is positively modulated by innate immunity-derived several external factors, ensuring that even low (near threshold doses of CXCL12 still exert a robust chemotactic influence on HSPCs.

  12. 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

  13. Factor Analysis

    OpenAIRE

    Graffelman, Jan

    2013-01-01

    Factor analysis is a multivariate statistical method for data reduction that originated in psychometrics and has found applications in many branches of science. The method aims to describe the correlation structure between a large set of observed variables in terms of a few underlying latent variables called factors. Factor analysis employs a specific model, where observed variables are modelled as linear combinations of common factors plus a specific error term. This model can be estimated b...

  14. 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.)

  15. Risk Factors

    Science.gov (United States)

    ... Depression has been found to be a risk factor for development of heart disease. Depression occurs in up to 20% of people with ... and has been found to be a risk factor also for subsequent heart attack, the ... Fortunately, depression in patients with heart disease responds well to ...

  16. Robust factorization

    DEFF Research Database (Denmark)

    Aanæs, Henrik; Fisker, Rune; Åström, Kalle; Carstensen, Jens Michael

    2002-01-01

    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. These...

  17. Transforming growth factor beta 1 (TGF-beta 1) induced neutrophil recruitment to synovial tissues: implications for TGF-beta-driven synovial inflammation and hyperplasia

    International Nuclear Information System (INIS)

    We have studied the consequences of introducing human recombinant transforming growth factor beta 1 (hrTGF-beta 1) into synovial tissue of the rat, to begin to better understand the significance of the fact that biologically active TGF-beta is found in human arthritic synovial effusions. Within 4-6 h after the intra-articular injection of 1 microgram of hrTGF-beta 1 into rat knee joints, extensive recruitment of polymorphonuclear leukocytes (PMNs) was observed. Cytochemistry and high resolution histological techniques were used to quantitate the influx of PMNs, which peaked 6 h post-injection. In a Boyden chamber assay, hrTGF-beta 1 at 1-10 fg/ml elicited a chemotactic response from PMNs greater in magnitude than that evoked by FMLP, establishing that TGF-beta 1 is an effective chemotactic agent for PMNs in vitro as well as in vivo. That PMNs may represent an important source of TGF-beta in inflammatory infiltrates was strongly suggested by a demonstration that stored TGF-beta 1 was secreted during phorbol myristate acetate-stimulated degranulation in vitro. Acid/ethanol extracts of human PMNs assayed by ELISA contained an average of 355 ng of TGF/beta 1 per 10(9) cells potentially available for secretion during degranulation of PMNs. [3H]Thymidine incorporation in vivo and autoradiography of tissue sections revealed that widespread cell proliferation was triggered by TGF-beta 1 injection. Synovial lining cells and cells located deep within the subsynovial connective tissue were identified as sources of at least some of the new cells that contribute to TGF-beta 1-induced hyperplasia. Our results demonstrate that TGF-beta is capable of exerting pathogenic effects on synovial tissue and that PMNs may represent a significant source of the TGF-beta present in synovial effusions

  18. Quality factors

    International Nuclear Information System (INIS)

    The quality factor, Q, is a dimensionless modifier used in converting absorbed dose, expressed in rads (or grays), to dose equivalent, expressed in rems (or seiverts). The dose equivalent is used in radiation protection to account for the biological effectiveness of different kinds of radiation. The quality factor is related to both the linear energy transfer (LET) and relative biological effectiveness (RBE). The RBE's obtained from biological experiments depend in a complex way on the observed biological effect, the specific test organism, and the experimental conditions. Judgement is involved, therefore, in the choice of the quality factor. Questions regarding the adequacy of current Q values for neutrons were raised first in a 1980 statement by the National Council on Radiation Protection (NCRP) and later in a 1985 statement by the International Commission on Radiological Protection (ICRP). In 1980, the NCRP alerted the technical community to possible future increases between a factor of three and ten in the Q for neutrons, and in 1985, the ICRP suggested an increase by a factor of two in Q for neutrons. Both the ICRP and NRCP are now recommending essentially the same guidance with regard to Q for neutrons: an increase by a factor of two. The Q for neutrons is based on a large, albeit unfocused, body of experimental data. In spite of the lack of focus, the data supporting a change in the neutron quality factor are substantial. However, the proposed doubling of Q for neutrons is clouded by other issues regarding its application. 33 refs., 4 figs., 6 tabs

  19. 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

  20. 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

  1. 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.

  2. Chemotactic behavior of the sperm of chitons (Mollusca: Polyplacophora).

    Science.gov (United States)

    Miller, R L

    1977-11-01

    Observations of sperm behavior in the vicinity of gradients of egg-water or alcohol extracts of whole freshly-spawned eggs of several chitons reveal what appear to be directed movements of sperm up the gradient, resulting in the aggregation of motile sperm at the gradient source. Plots of the tracks of the sperm approaching the gradient source show that the cells increase the time during which they move toward the source and decrease the time spent moving away. Although this resembles the kinesis behavior shown by bacteria in a gradient, the path directions are markedly non-random. The reorientation behavior of thigmotactic sperm involves enlargement of the normal circular path diameter in the direction of the source and an alternation of tight loops and wide circular arcs, with the latter made in the direction of the source. The form of the path of attracted chiton sperm is like that observed during chemotaxis of the sperm of the hydroid Tubularia and the tunicate Ciona and resembles the behavior of Ciona sperm in that there is no increase in velocity as the cells move up the gradient. However, unlike the cnidarian and urochordate cases, the attracting substances extracted from chiton eggs do not act species-specifically. PMID:925668

  3. Chemotactic peptide modulation of actin assembly and locomotion in neutrophils

    OpenAIRE

    1984-01-01

    To determine the relationship between the state of actin polymerization in neutrophils and the formyl-methionyl-leucyl-phenylalanine (fMLP)- induced changes in the locomotive behavior of neutrophils, the mean rate of locomotion (mROL), the percent G-actin, and the relative F- actin content of neutrophils were determined. The mROL was quantified by analysis of the locomotion of individual cells; the percentage of total actin as G-actin was measured by DNase I inhibition; and the F- actin was d...

  4. 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.

  5. 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...

  6. 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.

  7. Risk factors

    International Nuclear Information System (INIS)

    This article deals with the development of risk management in the gas sector business: why a risk factor legal mention must precede any published financial information? Do gas companies have to face new risks? Is there specific risks bound to gas activities? Why companies want to master their risks? Is it mandatory or just a new habit? Do they expect a real benefit in return? These are the risk management questions that are analyzed in this article which is based on the public communication of 15 gas companies randomly selected over the world. The information comes from their annual reports or from documents available on their web sites. The intention of this document is not to be exhaustive or to make statistics but only to shade light on the risk factors of the gas sector. (J.S.)

  8. 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.

  9. 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.

  10. Role of calcium in neutrophil activation by Japanese encephalitis virus - induced macrophage derived factor

    International Nuclear Information System (INIS)

    The role of cytosolic Ca2+ concentration in neutrophils stimulated with macrophage derived neutrophil chemotactic factor (MDF) produced following Japanese encephalitis virus infection in mice was correlated with cell functions. MDF-induced Ca2+ influx from extracellular milieu and release from intracellular store resulted in rise of cytosolic Ca2+ in a dose-dependent manner and was independent of protein kinase C. Macrophages and B cells did not show cytosolic Ca2+ changes wile T lymphocytes showed slight rise when stimulated with MDF. Neutrophil chemotaxis in the absence of Ca2+ was slightly different from that in presence of Ca2+. Pretreatment of neutrophils with 3,4,5-trimethoxy-benzoic acid-8-(dimethylamino)-octylester (TMB-8) inhibited the chemotaxis. It was observed that superoxide production and de-granulation by neutrophils after stimulation with MDF was not depend on the presence of extracellular calcium, but stripping of intracellular calcium resulted in abrogation of neutrophil activation. Thus, mobilization of intracellular calcium seems to be necessary for neutrophil activation by MDF. (author)

  11. Human factors

    International Nuclear Information System (INIS)

    This paper discusses the evolution of human factors engineering within PP and L's Nuclear Department. From the initial appearance in the DCRDR (Detailed Control Room Design Review), the discipline today has responsibilities in seven functional areas. Examples of programs and projects will be discussed. The main intent is not a detailed discussion of any one area, but rather, the areas such a program might encompass in any utility. The listener therefore might return from the symposium with ideas to initiate or enrich a similar program

  12. Exaggerated hepatotoxicity of acetaminophen in mice lacking tumor necrosis factor receptor-1 Potential role of inflammatory mediators

    International Nuclear Information System (INIS)

    Transgenic mice with a targeted disruption of the tumor necrosis factor receptor 1 (TNFR1) gene were used to analyze the role of TNF-α in pro- and anti-inflammatory mediator production and liver injury induced by acetaminophen. Treatment of wild-type mice with acetaminophen (300 mg/kg) resulted in centrilobular hepatic necrosis. This was correlated with expression of inducible nitric oxide synthase (NOS II) and nitrotyrosine staining of the liver. Expression of macrophage chemotactic protein-1 (MCP-1), KC/gro, interleukin-1β (IL-1β), matrix metalloproteinase-9 (MMP-9), and connective tissue growth factor (CTGF), inflammatory mediators known to participate in tissue repair, as well as the anti-inflammatory cytokine, interleukin-10 (IL-10), also increased in the liver following acetaminophen administration. TNFR1-/- mice were found to be significantly more sensitive to the hepatotoxic effects of acetaminophen than wild-type mice. This was correlated with more rapid and prolonged induction of NOS II in the liver and changes in the pattern of nitrotyrosine staining. Acetaminophen-induced expression of MCP-1, IL-1β, CTGF, and MMP-9 mRNA was also delayed or reduced in TNFR1-/- mice relative to wild-type mice. In contrast, increases in IL-10 were more rapid and more pronounced. These data demonstrate that signaling through TNFR1 is important in inflammatory mediator production and toxicity induced by acetaminophen

  13. 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

  14. 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

  15. 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. PMID:26852939

  16. 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.

  17. A DC-81-indole conjugate agent suppresses melanoma A375 cell migration partially via interrupting VEGF production and stromal cell-derived factor-1α-mediated signaling

    International Nuclear Information System (INIS)

    Pyrrolo[2,1-c][1,4]benzodiazepine (PBD) chemicals are antitumor antibiotics inhibiting nucleic acid synthesis. An indole carboxylate-PBD hybrid with six-carbon spacer structure (IN6CPBD) has been previously demonstrated to induce melanoma cell apoptosis and reduce metastasis in mouse lungs. This study aimed at investigating the efficacy of the other hybrid compound with four-carbon spacer (IN4CPBD) and elucidating its anti-metastatic mechanism. Human melanoma A375 cells with IN4CPBD treatment underwent cytotoxicity and apoptosis-associated assays. Transwell migration assay, Western blotting, and ELISA were used for mechanistic study. IN4CPBD exhibited potent melanoma cytotoxicity through interrupting G1/S cell cycle progression, increasing DNA fragmentation and hypodipoidic DNA contents, and reducing mitochondrial membrane potential. Caspase activity elevation suggested that both intrinsic and extrinsic pathways were involved in IN4CPBD-induced melanoma apoptosis. IN4CPBD up-regulated p53 and p21, thereby concomitantly derailing the equilibrium between Bcl-2 and Bax levels. Transwell migration assay demonstrated that stromal cell-derived factor-1α (SDF-1α) stimulated A375 cell motility, while kinase inhibitors treatment confirmed that Rho/ROCK, Akt, ERK1/2, and p38 MAPK pathways were involved in SDF-1α-enhanced melanoma migration. IN4CPBD not only abolished the SDF-1α-enhanced chemotactic motility but also suppressed constitutive MMP-9 and VEGF expression. Mechanistically, IN4CPBD down-regulated Akt, ERK1/2, and p38 MAPK total proteins and MYPT1 phosphorylation. In conclusion, beyond the fact that IN4CPBD induces melanoma cell apoptosis at cytotoxic dose, the interruption in the VEGF expression and the SDF-1α-related signaling at cytostatic dose may partially constitute the rationale for its in vivo anti-metastatic potency. - Research highlights: → A novel carboxylate-PBD hybrid as anti-melanoma drug. → IN4CPBD interrupts melanoma cell cycle progression

  18. 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

  19. Factor V deficiency

    Science.gov (United States)

    Factor V deficiency is a condition that is passed down through families, which affects the ability of the blood ... These proteins are called blood coagulation factors. Factor V deficiency is caused by a lack of Factor ...

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. 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 ...

  5. 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 ...

  6. 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 ...

  7. Positive Portfolio Factors

    OpenAIRE

    Stephen J. Brown; William N. Goetzmann; Mark Grinblatt

    1998-01-01

    We use an iterative relocation algorithm to identify factors in common stock returns. The benefit of the approach is that factors are portfolios of assets with non-negative weights. As a result, they are readily interpretable in terms of the characteristics of the underlying securities. The positive portfolio factors have comparatively high explanatory power in sample and out of sample. We find evidence of a size factor and factors identified with certain industries. Factors extracted from th...

  8. 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

  9. 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

  10. 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.

  11. 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

  12. 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.

  13. Bayesian exploratory factor analysis

    OpenAIRE

    Gabriella Conti; Sylvia Frühwirth-Schnatter; James Heckman; Rémi Piatek

    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 corresponding factor loadings. Classical identifi cation criteria are applied and integrated into our Bayesian procedure to generate models that are stable and clearly interpretable. A Monte Carlo study c...

  14. Bayesian Exploratory Factor Analysis

    OpenAIRE

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

    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 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 co...

  15. Bayesian Exploratory Factor Analysis

    OpenAIRE

    Gabriella Conti; Sylvia Fruehwirth-Schnatter; Heckman, James J.; Remi Piatek

    2014-01-01

    This paper develops and applies a Bayesian approach to Exploratory Factor Analysis that improves on \\emph{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 s...

  16. Bayesian exploratory factor analysis

    OpenAIRE

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

    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 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 st...

  17. Bayesian exploratory factor analysis

    OpenAIRE

    Conti, Gabriella; Frühwirth-Schnatter, Sylvia; Heckman, James; Piatek, Rémi

    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 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 co...

  18. 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

  19. 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 ...

  20. 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 ...

  1. 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...

  2. 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)

  3. 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

  4. Environmental Factors in Autism

    OpenAIRE

    Grabrucker, Andreas M

    2013-01-01

    Autism is a neurodevelopmental disorders characterized by impairments in communication and social behavior, and by repetitive behaviors. Although genetic factors might be largely responsible for the occurrence of autism they cannot fully account for all cases and it is likely that in addition to a certain combination of autism-related genes, specific environmental factors might act as risk factors triggering the development of autism. Thus, the role of environmental factors in autism is an im...

  5. Environmental factors in autism

    OpenAIRE

    AndreasMartinGrabrucker

    2013-01-01

    Autism is a neurodevelopmental disorders characterized by impairments in communication and social behavior, and by repetitive behaviors. Although genetic factors might be largely responsible for the occurrence of autism they cannot fully account for all cases and it is likely that in addition to a certain combination of autism-related genes, specific environmental factors might act as risk factors triggering the development of autism. Thus, the role of environmental factors in autism is an im...

  6. 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...

  7. Multilevel Mixture Factor Models

    Science.gov (United States)

    Varriale, Roberta; Vermunt, Jeroen K.

    2012-01-01

    Factor analysis is a statistical method for describing the associations among sets of observed variables in terms of a small number of underlying continuous latent variables. Various authors have proposed multilevel extensions of the factor model for the analysis of data sets with a hierarchical structure. These Multilevel Factor Models (MFMs)…

  8. 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.

  9. 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

  10. Factoring groups into subsets

    CERN Document Server

    Szabo, Sandor

    2009-01-01

    Decomposing an abelian group into a direct sum of its subsets leads to results that can be applied to a variety of areas, such as number theory, geometry of tilings, coding theory, cryptography, graph theory, and Fourier analysis. Focusing mainly on cyclic groups, Factoring Groups into Subsets explores the factorization theory of abelian groups. The book first shows how to construct new factorizations from old ones. The authors then discuss nonperiodic and periodic factorizations, quasiperiodicity, and the factoring of periodic subsets. They also examine how tiling plays an important role in n

  11. 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...... 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...

  12. 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

  13. The Complement Inhibitor Factor H Generates an Anti-Inflammatory and Tolerogenic State in Monocyte-Derived Dendritic Cells.

    Science.gov (United States)

    Olivar, Rut; Luque, Ana; Cárdenas-Brito, Sonia; Naranjo-Gómez, Mar; Blom, Anna M; Borràs, Francesc E; Rodriguez de Córdoba, Santiago; Zipfel, Peter F; Aran, Josep M

    2016-05-15

    The activation of the complement system is a key initiating step in the protective innate immune-inflammatory response against injury, although it may also cause harm if left unchecked. The structurally related soluble complement inhibitors C4b-binding protein (C4BP) and factor H (FH) exert a tight regulation of the classical/lectin and alternative pathways of complement activation, respectively, attenuating the activity of the C3/C5 convertases and, consequently, avoiding serious damage to host tissues. We recently reported that the acute-phase C4BP isoform C4BP lacking the β-chain plays a pivotal role in the modulation of the adaptive immune responses. In this study, we demonstrate that FH acts in the early stages of monocyte to dendritic cell (DC) differentiation and is able to promote a distinctive tolerogenic and anti-inflammatory profile on monocyte-derived DCs (MoDCs) challenged by a proinflammatory stimulus. Accordingly, FH-treated and LPS-matured MoDCs are characterized by altered cytoarchitecture, resembling immature MoDCs, lower expression of the maturation marker CD83 and the costimulatory molecules CD40, CD80, and CD86, decreased production of key proinflammatory Th1-cytokines (IL-12, TNF-α, IFN-γ, IL-6, and IL-8), and preferential production of immunomodulatory mediators (IL-10 and TGF-β). Moreover, FH-treated MoDCs show low Ag uptake and, when challenged with LPS, display reduced CCR7 expression and chemotactic migration, impaired CD4(+) T cell alloproliferation, inhibition of IFN-γ secretion by the allostimulated T cells, and, conversely, induction of CD4(+)CD127(low/negative)CD25(high)Foxp3(+) regulatory T cells. Thus, this novel noncanonical role of FH as an immunological brake able to directly affect the function of MoDCs in an inflammatory environment may exhibit therapeutic potential in hypersensitivity, transplantation, and autoimmunity. PMID:27076676

  14. Intraocular cytokines in retinal vein occlusion and its relation to the efficiency of anti-vascular endothelial growth factor therapy

    Directory of Open Access Journals (Sweden)

    Andrey G Shchuko

    2015-01-01

    Full Text Available Purpose: To analyze the change in the concentration of intraocular cytokines (ICs in patients with retinal vein occlusion (RVO before and after intravitreal ranibizumab therapy (IVR, and to find the correlations of IC with clinical activity of RVO and efficiency of treatment. Materials and Methods: Forty-four patients aged 46–79 years old (mean age: 60.7 ± 7.5 years old with RVO and macular edema (18 patients – with central RVO, 26 – with branch RVO treated with IVR were included into the study. The concentrations of 27 cytokines were simultaneously measured in aqueous humor by flow fluorometry using Bio-Plex Pro Human Cytokine Panel, 27-Plex (Bio-Rad Laboratories, USA at baseline and after the first IVR. Control group consisted of 20 age-matched patients. Results: The levels of 11 cytokines (vascular endothelial growth factor [VEGF], receptor antagonist interleukin-1, interleukin-6 [IL-6], IL-8, IL-9, IL-10, IL-12r70, IL-13, IL-15, monocyte chemotactic protein-1 [MCP-1], regulated on activation, normal T expressed and secreted were significantly (P < 0.05 different compared to control and significantly (P < 0.05 changed after IVR both in central and branch RVO. The patients were divided into two groups: the first -"effective" and the second - "partially effective" therapy. The second group characterized by the higher concentrations of VEGF, IL-8, IL-10, IL-17, and MCP-1 at baseline compared to the first group. Conclusion: The patients with RVO were characterized by the increased levels of VEGF and other pro- and anti-inflammatory cytokines and chemokines. Aqueous concentration of cytokines were different in patients with central and branch RVO and significantly changed after IVR. Insufficient response to IVR was associated with activation of immune-inflammatory processes.

  15. Evolutionary factor analysis

    OpenAIRE

    Motta, Giovanni

    2009-01-01

    Linear factor models have attracted considerable interest over recent years especially in the econometrics literature. The intuitively appealing idea to explain a panel of economic variables by a few common factors is one of the reasons for their popularity. From a statistical viewpoint, the need to reduce the cross-section dimension to a much smaller factor space dimension is obvious considering the large data sets available in economics and finance. One of the characteristics of the traditi...

  16. 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...

  17. 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...

  18. 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 ...

  19. New thrombopoietic growth factors

    OpenAIRE

    Kuter, David J.

    2007-01-01

    Although development of first-generation thrombopoietic growth factors (recombinant human thrombopoietin [TPO] and pegylated recombinant human megakaryocyte growth and development factor [PEG-rHuMGDF]) was stopped due to development of antibodies to PEG-rHuMGDF, nonimmunogenic second-generation thrombopoietic growth factors with unique pharmacologic properties have been developed. TPO peptide mimetics contain TPO receptor-activating peptides inserted into complementarity-determining regions o...

  20. 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.

  1. 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.

  2. Universal Factor Graphs

    CERN Document Server

    Feige, Uriel

    2012-01-01

    The factor graph of an instance of a symmetric constraint satisfaction problem on n Boolean variables and m constraints (CSPs such as k-SAT, k-AND, k-LIN) is a bipartite graph describing which variables appear in which constraints. The factor graph describes the instance up to the polarity of the variables, and hence there are up to 2km instances of the CSP that share the same factor graph. It is well known that factor graphs with certain structural properties make the underlying CSP easier to either solve exactly (e.g., for tree structures) or approximately (e.g., for planar structures). We are interested in the following question: is there a factor graph for which if one can solve every instance of the CSP with this particular factor graph, then one can solve every instance of the CSP regardless of the factor graph (and similarly, for approximation)? We call such a factor graph universal. As one needs different factor graphs for different values of n and m, this gives rise to the notion of a family of unive...

  3. Exploratory Bi-Factor Analysis

    Science.gov (United States)

    Jennrich, Robert I.; Bentler, Peter M.

    2011-01-01

    Bi-factor analysis is a form of confirmatory factor analysis originally introduced by Holzinger. The bi-factor model has a general factor and a number of group factors. The purpose of this article is to introduce an exploratory form of bi-factor analysis. An advantage of using exploratory bi-factor analysis is that one need not provide a specific…

  4. 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

  5. PAYMENT CAPACITY SENSITIVITY FACTORS

    Directory of Open Access Journals (Sweden)

    Daniel BRÎNDESCU – OLARIU

    2014-11-01

    The results of the study facilitate the determination and classification of the main sensitivity factors for the payment capacity at sample level, the establishment of general benchmarks for the payment capacity (as no such benchmarks currently exist in the Romanian literature and the identification of the mechanisms through which the variation of different factors impacts the payment capacity.

  6. Plant transcription factors.

    Science.gov (United States)

    Meshi, T; Iwabuchi, M

    1995-12-01

    Transcriptional regulation of gene expression relies on the recognition of promoter elements by transcription factors. In the past several years, a considerable number of (putative) transcription factors have been identified in plants. Some genes coding for these factors were isolated by south-western screening with oligonucleotides as a probe or by homology-based screening, and others were initially isolated by genetic means and subsequently identified as the genes for transcription factors. These transcription factors often form families of structurally related proteins with similar DNA-binding specificities and in addition, they are sometimes involved in related phenomena. Some groups of factors homo- and/or heterodimerize to increase the length and variability of the target sequences. Transcriptional activators, in general, comprise a modular activation domain. The activities of the transcription factors are controlled by post-translational modification, like phosphorylation and glycosylation, as well as at the levels of nuclear transport, oligomerization, etc. In this review, we will summarize the current knowledge of plant transcription factors to help understand the mechanistic aspects of the transcriptional regulation of genes. PMID:8589926

  7. 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 ...

  8. Respirator field performance factors

    International Nuclear Information System (INIS)

    The Industrial Hygiene Group assisted OSHA and the NRC in measurements of respirator performance under field conditions. They reviewed problems associated with sampling aerosols within the respirator in order to determine fit factors (FFs) or field performance factor (FPF). In addition, they designed an environmental chamber study to determine the effects of temperature and humidity on a respirator wearer

  9. Dynamic factor models

    OpenAIRE

    Breitung, Jörg; Eickmeier, Sandra

    2005-01-01

    Factor models can cope with many variables without running into scarce degrees of freedom problems often faced in a regression-based analysis. In this article we review recent work on dynamic factor models that have become popular in macroeconomic policy analysis and forecasting. By means of an empirical application we demonstrate that these models turn out to be useful in investigating macroeconomic problems.

  10. Sparse exploratory factor analysis

    OpenAIRE

    Fontanella, Sara; Trendafilov, Nickolay; Adachi, Kohei

    2014-01-01

    Sparse principal component analysis is a very active research area in the last decade. In the same time, there are very few works on sparse factor analysis. We propose a new contribution to the area by exploring a procedure for sparse factor analysis where the unknown parameters are found simultaneously.

  11. 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...

  12. 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.

  13. Low-affinity platelet factor 4 1H NMR derived aggregate equilibria indicate a physiologic preference for monomers over dimers and tetramers

    International Nuclear Information System (INIS)

    Low-affinity platelet factor 4 (LA-PF4), unlike another related, sequentially homologous platelet specific protein, platelet factor 4 (PF4), is an active mitogenic and chemotactic agent. PF4 exhibits a high binding affinity for heparin, while LA-PF4 does not. Both PF4 and LA-PF4 can exist in dimer and tetramer aggregate states. Equilibrium constants for PF4 aggregation have recently been estimated from fractional populations derived from proton nuclear magnetic resonance (NMR) integrals assigned to resonances in monomer, dimer, and tetramer states. On a 500-MHzNMR time scale, relatively slow exchange among LA-PF4 aggregate species has also allowed Tyr 15 ring proton resonances to be assigned for monomer, dimer, and tetramer states in LA-PF4. As a function of pH and ionic strength, equilibrium association constants for LA-PF4 dimer (KD) and tetramer (KT) formation have been estimated from Tyr 15 ring proton resonance integrals. Analysis of the pH dependence of KD and KT suggests that electrostatic interactions probably among Glu/Asp and Lys/Arg side chains form the predominant force in the monomer-monomer binding process, i.e., KD, while like-charge repulsion due to proximal, intersubunit Glu/Asp residues decreases KT as the pH is raised. At pH 7 and low ionic strength, the dimer state is highly favored over the tetramer state. Elevating the solvent ionic strength at pH 7 destabilizes the dimer state. Under these more physiologic conditions, i.e., pH 7 and 0.1-0.2 M NaCl, LA-PF4 monomers are highly favored over dimers and tetramers. For PF4 under similar solvent conditions, tetramers predominate. Differences in biological activities between these homologous platelet-specific proteins may be the result, at least in part, of differing aggregation properties

  14. 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

  15. Koedam {beta} factors revisited

    Energy Technology Data Exchange (ETDEWEB)

    Lawler, J.E. [Physics Department, University of Wisconsin, Madison, WI (United States); Doughty, D.A. [Perkin-Elmer Optoelectronics, Santa Clara, CA (United States); Lister, G.G. [OSRAM SYLVANIA Inc., Beverly, MA (United States)

    2002-07-21

    A Koedam {beta} factor makes it possible to compute the total output power in line radiation from a positive column discharge using a single radiance measurement normal to an aperture in the wall. The results of analytic derivations of {beta} factors are presented for columns with uniform ({beta}=1.0) and parabolic ({beta}=0.75) excitation rates per unit volume and with negligible opacity. A Monte Carlo code for simulating radiation trapping with a spatially uniform density of absorbing atoms is then used to determine {beta} factors as a function of opacity. The code includes partial frequency redistribution and a Voigt line shape with radiative broadening, resonance collisional broadening, and Doppler broadening. The resulting {beta} factors are found to be nearly independent of opacity over a wide range of column radii for spectral line shapes dominated by Doppler broadening or by resonance collisional broadening. Additional Monte Carlo simulations are used to study {beta} factors as a function of a non-uniform density of absorbing atoms from radial cataphoresis with line shapes dominated by Doppler broadening, foreign gas broadening, and resonance collisional broadening. Radial cataphoresis is found to increase {beta} factors in all cases. Geometrical effects, refraction, and imperfect transmission at the glass wall are studied and found to decrease {beta} factors. (author)

  16. Koedam β factors revisited

    International Nuclear Information System (INIS)

    A Koedam β factor makes it possible to compute the total output power in line radiation from a positive column discharge using a single radiance measurement normal to an aperture in the wall. The results of analytic derivations of β factors are presented for columns with uniform (β=1.0) and parabolic (β=0.75) excitation rates per unit volume and with negligible opacity. A Monte Carlo code for simulating radiation trapping with a spatially uniform density of absorbing atoms is then used to determine β factors as a function of opacity. The code includes partial frequency redistribution and a Voigt line shape with radiative broadening, resonance collisional broadening, and Doppler broadening. The resulting β factors are found to be nearly independent of opacity over a wide range of column radii for spectral line shapes dominated by Doppler broadening or by resonance collisional broadening. Additional Monte Carlo simulations are used to study β factors as a function of a non-uniform density of absorbing atoms from radial cataphoresis with line shapes dominated by Doppler broadening, foreign gas broadening, and resonance collisional broadening. Radial cataphoresis is found to increase β factors in all cases. Geometrical effects, refraction, and imperfect transmission at the glass wall are studied and found to decrease β factors. (author)

  17. Environmental factors in autism

    Directory of Open Access Journals (Sweden)

    AndreasMartinGrabrucker

    2013-01-01

    Full Text Available Autism is a neurodevelopmental disorders characterized by impairments in communication and social behavior, and by repetitive behaviors. Although genetic factors might be largely responsible for the occurrence of autism they cannot fully account for all cases and it is likely that in addition to a certain combination of autism-related genes, specific environmental factors might act as risk factors triggering the development of autism. Thus, the role of environmental factors in autism is an important area of research and recent data will be discussed in this review. Interestingly, the results show that many environmental risk factors are interrelated and their identification and comparison might unveil a common scheme of alterations on a contextual as well as molecular level. For example, both, disruption in the immune system and in zinc homeostasis may affect synaptic transmission in autism. Thus, here, a model is proposed that interconnects the most important and scientifically recognized environmental factors. Moreover, similarities in how these risk factors impact synapse function are discussed and a possible influence on an already well described genetic pathway leading to the development of autism via zinc homeostasis is proposed.

  18. 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

  19. 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

  20. 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.

  1. Quivers from Matrix Factorizations

    CERN Document Server

    Aspinwall, Paul S

    2010-01-01

    We discuss how matrix factorizations offer a practical method of computing the quiver and associated superpotential for a hypersurface singularity. This method also yields explicit geometrical interpretations of D-branes (i.e., quiver representations) on a resolution given in terms of Grassmannians. As an example we analyze some non-toric singularities which are resolved by a single CP1 but have "length" greater than one. These examples have a much richer structure than conifolds. A picture is proposed that relates matrix factorizations in Landau-Ginzburg theories to the way that matrix factorizations are used in this paper to perform noncommutative resolutions.

  2. 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.

  3. 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)

  4. Brain Tumor Risk Factors

    Science.gov (United States)

    ... for example), unusual symptoms such as headaches or short-term memory loss can be investigated with your family history in mind. Click here to view our webinars on Causes and Risk Factors of Brain Tumors. Additional information ...

  5. Coagulation Factors Test

    Science.gov (United States)

    ... be limited. Home Visit Global Sites Search Help? Coagulation Factors Share this page: Was this page helpful? ... if a person has a sufficient amount of coagulation activity in order to control the blood clotting ...

  6. 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...

  7. Factors Influencing Biotite Weathering

    OpenAIRE

    Reed, Ryan R.

    2000-01-01

    Factors Influencing Biotite Weathering by Ryan Reed Lucian W. Zelazny, Chairman Crop and Soil Environmental Sciences (ABSTRACT) Weathering of biotite supplies nutrients such as K+ and weathers into vermiculite/montmorillonite or kaolinite, which have varying influences on soil properties and characteristics. This study was conducted to determine if the weathering mechanisms of biotite are controlled by temperature, or if other factors, such as vegetation or leaching inten...

  8. 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

  9. 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...

  10. 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...

  11. 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 ...

  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. Risk Factors of Cholangiocarcinoma

    OpenAIRE

    Tyson, Gia L.; El-Serag, Hashem B.

    2011-01-01

    Cholangiocarcinoma is the second most common primary hepatic malignancy after hepatocellular cancer. It accounts for approximately 10–25% of all hepatobiliary malignancies. There are considerable geographic and demographic variations in the incidence of cholangiocarcinoma. There are several established risk factors for CC including parasitic infections, primary sclerosing cholangitis, biliary-duct cysts, hepatolithiasis, and toxins. Other less-established, potential risk factors include infla...

  14. 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...

  15. 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...

  16. Psychological Factors in Asthma

    OpenAIRE

    Van Lieshout Ryan J; MacQueen Glenda

    2008-01-01

    Asthma has long been considered a condition in which psychological factors have a role. As in many illnesses, psychological variables may affect outcome in asthma via their effects on treatment adherence and symptom reporting. Emerging evidence suggests that the relation between asthma and psychological factors may be more complex than that, however. Central cognitive processes may influence not only the interpretation of asthma symptoms but also the manifestation of measurable changes in im...

  17. 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...

  18. 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.

  19. 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。

  20. 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

  1. Exploratory Bi-factor Analysis

    OpenAIRE

    Jennrich, Robert I.; Bentler, Peter M.

    2011-01-01

    Bi-factor analysis is a form of confirmatory factor analysis originally introduced by Holzinger. The bi-factor model has a general factor and a number of group factors. The purpose of this paper is to introduce an exploratory form of bi-factor analysis. An advantage of using exploratory bi-factor analysis is that one need not provide a specific bi-factor model a priori. The result of an exploratory bi-factor analysis, however, can be used as an aid in defining a specific bi-factor model. Our ...

  2. Breast cancer risk factors.

    Science.gov (United States)

    Kamińska, Marzena; Ciszewski, Tomasz; Łopacka-Szatan, Karolina; Miotła, Paweł; Starosławska, Elżbieta

    2015-09-01

    Breast cancer is the most frequently diagnosed neoplastic disease in women around menopause often leading to a significant reduction of these women's ability to function normally in everyday life. The increased breast cancer incidence observed in epidemiological studies in a group of women actively participating in social and professional life implicates the necessity of conducting multidirectional studies in order to identify risk factors associated with the occurrence of this type of neoplasm. Taking the possibility of influencing the neoplastic transformation process in individuals as a criterion, all the risk factors initiating the process can be divided into two groups. The first group would include inherent factors such as age, sex, race, genetic makeup promoting familial occurrence of the neoplastic disease or the occurrence of benign proliferative lesions of the mammary gland. They all constitute independent parameters and do not undergo simple modification in the course of an individual's life. The second group would include extrinsic factors conditioned by lifestyle, diet or long-term medical intervention such as using oral hormonal contraceptives or hormonal replacement therapy and their influence on the neoplastic process may be modified to a certain degree. Identification of modifiable factors may contribute to development of prevention strategies decreasing breast cancer incidence. PMID:26528110

  3. Breast cancer risk factors

    Directory of Open Access Journals (Sweden)

    Marzena Kamińska

    2015-09-01

    Full Text Available Breast cancer is the most frequently diagnosed neoplastic disease in women around menopause often leading to a significant reduction of these women’s ability to function normally in everyday life. The increased breast cancer incidence observed in epidemiological studies in a group of women actively participating in social and professional life implicates the necessity of conducting multidirectional studies in order to identify risk factors associated with the occurrence of this type of neoplasm. Taking the possibility of influencing the neoplastic transformation process in individuals as a criterion, all the risk factors initiating the process can be divided into two groups. The first group would include inherent factors such as age, sex, race, genetic makeup promoting familial occurrence of the neoplastic disease or the occurrence of benign proliferative lesions of the mammary gland. They all constitute independent parameters and do not undergo simple modification in the course of an individual’s life. The second group would include extrinsic factors conditioned by lifestyle, diet or long-term medical intervention such as using oral hormonal contraceptives or hormonal replacement therapy and their influence on the neoplastic process may be modified to a certain degree. Identification of modifiable factors may contribute to development of prevention strategies decreasing breast cancer incidence.

  4. The focus factor

    DEFF Research Database (Denmark)

    Nicolaisen, Jeppe; Frandsen, Tove Faber

    2015-01-01

    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 is...... 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...... effectively measures the intended phenomenon (i.e., journal specialisation). Only weak correlations were found between journal re-citations and obsolescence, journal self-citations, and number of references. Conclusions. The focus factor successfully measures journal specialisation over time. Measures based...

  5. 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

  6. 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

  7. 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.

  8. 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.

  9. 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......The model correction factor method is proposed as an alternative to traditional polynomial based response surface techniques in structural reliability considering a computationally time consuming limit state procedure as a 'black box'. The class of polynomial functions is replaced by a limit...... statebased on an idealized mechanical model to be adapted to the original limit state by the model correction factor. Reliable approximations are obtained by iterative use of gradient information on the original limit state function analogously to previous response surface approaches. However, the strength...

  10. 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.

  11. 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. ...

  12. 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.

  13. Factor analysis and scintigraphy

    International Nuclear Information System (INIS)

    The goal of factor analysis is usually to achieve reduction of a large set of data, extracting essential features without previous hypothesis. Due to the development of computerized systems, the use of largest sampling, the possibility of sequential data acquisition and the increase of dynamic studies, the problem of data compression can be encountered now in routine. Thus, results obtained for compression of scintigraphic images were first presented. Then possibilities given by factor analysis for scan processing were discussed. At last, use of this analysis for multidimensional studies and specially dynamic studies were considered for compression and processing

  14. 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....

  15. Dose conversion factors

    International Nuclear Information System (INIS)

    The following is discussed in this report: concepts and quantities used in calculating radiation dose from internal and external exposure. Tabulations of dose conversion factor for internal and external exposure to radionuclides. Dose conversion factors give dose per unit intake (internal) or dose per unit concentration in environment (external). Intakes of radionuclides for internal exposure and concentrations of radionuclides in environment for external exposure are assumed to be known. Intakes and concentrations are obtained, e.g., from analyses of environmental transport and exposure pathways. differences between dosimetry methods for radionuclides and hazardous chemicals are highlighted

  16. 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.

  17. Investigating Boolean Matrix Factorization

    Czech Academy of Sciences Publication Activity Database

    Snášel, V.; Platoš, J.; Krömer, P.; Húsek, Dušan; Neruda, Roman; Frolov, A. A.

    - : ACM, 2008 - (Ding, C.; Li, T.; Zhu, S.), s. 18-25 ISBN 978-1-60558-307-5. [DMMT'08. Workshop in Conjunction with SIGKDD 2008 /14./. Las Vegas (US), 24.08.2008-24.08.2008] Institutional research plan: CEZ:AV0Z10300504 Keywords : Boolean factor analysis * nonnegative matrix factorization * neural networks * information retrieval * data mining * binary data Subject RIV: BB - Applied Statistics, Operational Research http://users.cs.fiu.edu/~taoli/kdd08-workshop/DMMT08-Proceedings.pdf

  18. 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

  19. 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

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

    Science.gov (United States)

    Yoshimura, Teizo; Imamichi, Tomozumi; Weiss, Jonathan M.; Sato, Miwa; Li, Liangzhu; Matsukawa, Akihiro; Wang, Ji Ming

    2016-01-01

    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 upregulated neutrophil chemotactic chemokines, such as KC/CXCL1 or MIP-2/CXCL2. Physicochemical analysis indicated that an approximately 2–3 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 CSF, almost completely abrogated MCP-1-inducing activity of 4T1-sup, and recombinant GM-CSF potently upregulated 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 upregulate 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. PMID:26834744

  1. 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

  2. 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

  3. 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.

  4. 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

  5. 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 ...

  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. 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...

  8. 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)

  9. 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...

  10. 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...

  11. 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.

  12. MULTI-FACTOR INDEX MODELS

    OpenAIRE

    A. F. Shilo

    2014-01-01

    The paper presents an innovation factor formula for analysis of  factor characteristics’ influence on general result.As distinguished from a valuable positional factor formula the proposed one provides objective results of the analysis with high accuracy level.

  13. 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...

  14. Milestones and impact factors

    DEFF Research Database (Denmark)

    Ozonoff, David M; Grandjean, Philippe

    2010-01-01

    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...... 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...... 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...

  15. Breast cancer risk factors

    OpenAIRE

    Marzena Kamińska; Tomasz Ciszewski; Karolina Łopacka-Szatan; Paweł Miotła; Elżbieta Starosławska

    2015-01-01

    Breast cancer is the most frequently diagnosed neoplastic disease in women around menopause often leading to a significant reduction of these women's ability to function normally in everyday life. The increased breast cancer incidence observed in epidemiological studies in a group of women actively participating in social and professional life implicates the necessity of conducting multidirectional studies in order to identify risk factors associated with the occurrence of this type of neopla...

  16. Autoconcepto: factores e influencias

    OpenAIRE

    Casado Lozano, Ignacio; Hern??ndez Sande, Alberto; Manzano Bazaga, Elena

    2013-01-01

    En el presente art??culo se ha realizado una revisi??n bibliogr??fica sobre el autoconcepto y las ??ltimas investigaciones que aportan datos acerca de relaciones e influencias con diversas variables, as?? como los factores que podr??an componer el constructo del autoconcepto. Las investigaciones han sido seleccionadas para disponer de una selecci??n suficientemente reciente (a partir del a??o 2009 de publicaciones) para que pueda ayudar a dirigir otras futuras.

  17. Viral Interferon Regulatory Factors

    OpenAIRE

    Lee, Hye-Ra; Kim, Myung Hee; Lee, Jong-Soo; Liang, Chengyu; Jung, Jae U.

    2009-01-01

    Upon viral infection, the major defensive strategy employed by the host immune system is the activation of the interferon (IFN)-mediated antiviral pathway, which is overseen by IFN regulatory factors (IRFs). In order to complete their life cycles, viruses must find a way to modulate the host IFN-mediated immune response. Kaposi's sarcoma-associated herpesvirus (KSHV), a human tumor-inducing herpesvirus, has developed a unique mechanism for antagonizing cellular IFN-mediated antiviral activity...

  18. Implementing Boolean Matrix Factorization

    Czech Academy of Sciences Publication Activity Database

    Neruda, Roman; Snášel, V.; Platoš, J.; Krömer, P.; Húsek, Dušan; Frolov, A. A.

    Vol. Part I. Berlin : Springer, 2008 - (Kůrková, V.; Neruda, R.; Koutník, J.), s. 543-552 ISBN 978-3-540-87535-2. - (Lecture Notes in Computer Science. 5163). [ICANN 2008. International Conference on Artificial Neural Network s /18./. Prague (CZ), 03.09.2008-06.09.2008] Institutional research plan: CEZ:AV0Z10300504 Keywords : factor analysis * genetic algorithm * neural network s Subject RIV: IN - Informatics, Computer Science

  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 play ...

  20. 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...

  1. 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...

  2. 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...

  3. Factor PD-Clustering

    OpenAIRE

    Gettler Summa, Mireille; Palumbo, Francesco; Tortora, Cristina

    2012-01-01

    Factorial clustering methods have been developed in recent years thanks to the improving of computational power. These methods perform a linear transformation of data and a clustering on transformed data optimizing a common criterion. Factorial PD-clustering is based on Probabilistic Distance clustering (PD-clustering). PD-clustering is an iterative, distribution free, probabilistic, clustering method. Factor PD-clustering make a linear transformation of original variables into a reduced numb...

  4. 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...

  5. Genetic Factors of Obesity

    Czech Academy of Sciences Publication Activity Database

    Mazura, Ivan; Ochoa-Rebato, E.

    Budapest: Eötvös University Press, 2010 - (Bodzsár, E.; Susanne, C.), s. 119-140. (Biennial Books of the EAA. 6). ISBN 978-963-88941-0-6 R&D Projects: GA MŠk(CZ) 1M06014 Institutional research plan: CEZ:AV0Z10300504 Keywords : aetiology of obesity * genetic factors * obesity genes * polymorphism * obesity -associated syndromes Subject RIV: EB - Genetics ; Molecular Biology

  6. 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,...

  7. 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

  8. Nucleon Electromagnetic Form Factors

    International Nuclear Information System (INIS)

    Although nucleons account for nearly all the visible mass in the universe, they have a complicated structure that is still incompletely understood. The first indication that nucleons have an internal structure, was the measurement of the proton magnetic moment by Frisch and Stern (1933) which revealed a large deviation from the value expected for a point-like Dirac particle. The investigation of the spatial structure of the nucleon, resulting in the first quantitative measurement of the proton charge radius, was initiated by the HEPL (Stanford) experiments in the 1950s, for which Hofstadter was awarded the 1961 Nobel prize. The first indication of a non-zero neutron charge distribution was obtained by scattering thermal neutrons off atomic electrons. The recent revival of its experimental study through the operational implementation of novel instrumentation has instigated a strong theoretical interest. Nucleon electro-magnetic form factors (EMFFs) are optimally studied through the exchange of a virtual photon, in elastic electron-nucleon scattering. The momentum transferred to the nucleon by the virtual photon can be selected to probe different scales of the nucleon, from integral properties such as the charge radius to scaling properties of its internal constituents. Polarization instrumentation, polarized beams and targets, and the measurement of the polarization of the recoiling nucleon have been essential in the accurate separation of the charge and magnetic form factors and in studies of the elusive neutron charge form factor

  9. 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

  10. 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.

  11. 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…

  12. Perinatal risk factors for strabismus

    DEFF Research Database (Denmark)

    Torp-Pedersen, Tobias; Boyd, Heather A; Poulsen, Gry; Haargaard, Birgitte; Wohlfahrt, Jan; Holmes, Jonathan M; Melbye, Mads

    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....

  13. 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.

  14. 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.

  15. 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...

  16. Factorized Kalman Filtering

    Czech Academy of Sciences Publication Activity Database

    Suzdaleva, Evgenia

    Praha: ÚTIA AV ČR, 2006 - (Přikryl, J.; Šmídl, V.). s. 51-52 [International PhD Workshop on Interplay of Societal and Technical Decision-Making, Young Generation Viewpoint /7./. 25.09.2006-30.09.2006, Hrubá Skála] R&D Projects: GA MŠk 1M0572; GA ČR GP201/06/P434 Institutional research plan: CEZ:AV0Z10750506 Keywords : state estimation * factorized filters * traffic control Subject RIV: BC - Control Systems Theory

  17. Factorized Kalman Filtering

    Czech Academy of Sciences Publication Activity Database

    Suzdaleva, Evgenia

    Praha: ÚTIA AV ČR, 2006 - (Přikryl, J.; Andrýsek, J.; Šmídl, V.), s. 226-233 [International PhD Workshop on Interplay of Societal and Technical Decision-Making, Young Generation Viewpoint /7./. Hrubá Skála (CZ), 25.09.2006-30.09.2006] R&D Projects: GA MŠk 1M0572; GA ČR(CZ) GP201/06/P434 Grant ostatní: project TED ESF Institutional research plan: CEZ:AV0Z10750506 Keywords : state estimation * factorized filters * traffic control Subject RIV: BC - Control Systems Theory

  18. Improved Balanced Incomplete Factorization

    Czech Academy of Sciences Publication Activity Database

    Bru, R.; Marín, J.; Mas, J.; Tůma, Miroslav

    2010-01-01

    Roč. 31, č. 5 (2010), s. 2431-2452. ISSN 0895-4798 R&D Projects: GA AV ČR IAA100300802 Grant ostatní: GA AV ČR(CZ) M100300902 Institutional research plan: CEZ:AV0Z10300504 Source of funding: I - inštitucionálna podpora na rozvoj VO Keywords : preconditioned iterative methods * sparse matrices * incomplete decomposition s * approximate inverses * Sherman-Morrison formula * nonsymmetric matrices Subject RIV: BA - General Mathematics Impact factor: 1.725, year: 2010

  19. 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

  20. 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.

  1. 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-...

  2. 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...

  3. Effects of thermal fluctuation and the receptor-receptor interaction in bacterial chemotactic signalling and adaptation

    OpenAIRE

    Shi, Yu

    2001-01-01

    Bacterial chemotaxis is controlled by the conformational changes of the receptors, in response to the change of the ambient chemical concentration. In a statistical mechanical approach, the signalling due to the conformational changes is a thermodynamic average quantity, dependent on the temperature and the total energy of the system, including both ligand-receptor interaction and receptor-receptor interaction. This physical theory suggests to biology a new understanding of cooperation in lig...

  4. 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

  5. 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...

  6. Ca2+ spikes in the flagellum control chemotactic behavior of sperm

    OpenAIRE

    Böhmer, Martin; Van, Qui; Weyand, Ingo; Hagen, Volker; Beyermann, Michael; Matsumoto, Midori; Hoshi, Motonori; Hildebrand, Eilo; Kaupp, Ulrich Benjamin

    2005-01-01

    The events that occur during chemotaxis of sperm are only partly known. As an essential step toward determining the underlying mechanism, we have recorded Ca2+ dynamics in swimming sperm of marine invertebrates. Stimulation of the sea urchin Arbacia punctulata by the chemoattractant or by intracellular cGMP evokes Ca2+ spikes in the flagellum. A Ca2+ spike elicits a turn in the trajectory followed by a period of straight swimming (‘turn-and-run'). The train of Ca2+ spikes gives rise to repeti...

  7. 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...

  8. The effects of gliadin fragments on maturation and the chemotactic migratory ability of human dendritic cells

    Czech Academy of Sciences Publication Activity Database

    Palová-Jelínková, Lenka; Pecharová, Barbara; Cinová, Jana; Rožková, Daniela; Černá, M.; Dvořák, M.; Kverka, Miloslav; Tlaskalová, Helena; Tučková, Ludmila

    Tokyo : Elsevier, 2007, s. 240-240. [International Congress of Mucosal Immunology. Tokyo (JP), 09.08.2007-12.08.2007] R&D Projects: GA ČR GA310/05/2245; GA AV ČR KJB5020407 Institutional research plan: CEZ:AV0Z50200510 Keywords : celiac disease Subject RIV: EC - Immunology

  9. 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...

  10. 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...

  11. Demographic factors of economic growth

    OpenAIRE

    Fabiánová, Jana

    2013-01-01

    Development of the economic situation in recent years raises number of issues, including defining what are the factors of this development and whether it is possible to affect them. This thesis deals with the demographic factors of economic growth; those are factors associated with general population and factors which may have an impact on the country's economy. The main aim of this work is to precisely identify the demographic factor and analyze their development in the Czech Republic since ...

  12. Rotation of factors in factor analysis of dynamic radionuclide examinations

    International Nuclear Information System (INIS)

    A criterion is suggested of the selection of physiological factors for the application of factor analysis in nuclear medicine. Factors are characteristics directly immeasurable which we assume influence the characteristics measured on some set of objects. It is required that the values of factors be non-negative. Also required is the homogeneity of the background of factor images. The accuracy of estimate is demonstrated on simple examples of sequential scintigraphy on phantoms. Factor analysis may be one of the basic procedures of evaluating dynamic radionuclide examinations. (M.D.) 3 figs., 3 tabs., 13 refs

  13. Leukemia inhibitory factor (LIF).

    Science.gov (United States)

    Nicola, Nicos A; Babon, Jeffrey J

    2015-10-01

    Leukemia inhibitory factor (LIF) is the most pleiotropic member of the interleukin-6 family of cytokines. It utilises a receptor that consists of the LIF receptor β and gp130 and this receptor complex is also used by ciliary neurotrophic growth factor (CNTF), oncostatin M, cardiotrophin1 (CT1) and cardiotrophin-like cytokine (CLC). Despite common signal transduction mechanisms (JAK/STAT, MAPK and PI3K) LIF can have paradoxically opposite effects in different cell types including stimulating or inhibiting each of cell proliferation, differentiation and survival. While LIF can act on a wide range of cell types, LIF knockout mice have revealed that many of these actions are not apparent during ordinary development and that they may be the result of induced LIF expression during tissue damage or injury. Nevertheless LIF does appear to have non-redundant actions in maternal receptivity to blastocyst implantation, placental formation and in the development of the nervous system. LIF has also found practical use in the maintenance of self-renewal and totipotency of embryonic stem cells and induced pluripotent stem cells. PMID:26187859

  14. 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

  15. Auxin response factors.

    Science.gov (United States)

    Chandler, John William

    2016-05-01

    Auxin signalling involves the activation or repression of gene expression by a class of auxin response factor (ARF) proteins that bind to auxin response elements in auxin-responsive gene promoters. The release of ARF repression in the presence of auxin by the degradation of their cognate auxin/indole-3-acetic acid repressors forms a paradigm of transcriptional response to auxin. However, this mechanism only applies to activating ARFs, and further layers of complexity of ARF function and regulation are being revealed, which partly reflect their highly modular domain structure. This review summarizes our knowledge concerning ARF binding site specificity, homodimer and heterodimer multimeric ARF association and cooperative function and how activator ARFs activate target genes via chromatin remodelling and evolutionary information derived from phylogenetic comparisons from ARFs from diverse species. ARFs are regulated in diverse ways, and their importance in non-auxin-regulated pathways is becoming evident. They are also embedded within higher-order transcription factor complexes that integrate signalling pathways from other hormones and in response to the environment. The ways in which new information concerning ARFs on many levels is causing a revision of existing paradigms of auxin response are discussed. PMID:26487015

  16. Asma: factores precipitantes

    OpenAIRE

    Pimenta, José Eduardo da Silva Maia Ferreira

    2009-01-01

    A asma é uma doença pulmonar crónica caracterizada por obstrução das vias aéreas, inflamação e hiperreactividade brônquica. A asma afecta cerca de 150 milhões de pessoas de todas as idades no Mundo. Em Portugal calcula-se que atinja cerca de 600.000 pessoas incluindo crianças e adultos, calculando-se que afecte cerca de 11% das crianças e 5% dos adultos. A asma é uma doença que provavelmente resulta de uma interacção complexa entre múltiplos factores ambientais e influências...

  17. 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

  18. 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.

  19. Tiled QR factorization algorithms

    CERN Document Server

    Bouwmeester, Henricus; 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 important complexity result applies to all matrices where p and q are proportional, p = \\lambda q, with \\lambda >= 1, thereby encompassing many important situations in practice (least squares). We provide an extensive set of experiments that show the superiority of the new algorithms for tall matrices.

  20. 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.

  1. Anomalous Sudakov Form Factors

    CERN Document Server

    Ciafaloni, Marcello; Comelli, Denis

    2009-01-01

    While radiative corrections of infrared origin normally depress high energy amplitudes (Sudakov form factors), we find that in some cases resummation of leading effects produces exponentials with positive exponents, giving rise to amplitudes that grow indefinitely with energy. The effect happens in broken gauge theories like the electroweak sector of the Standard Model, and is related to the existence of amplitudes that do not respect the gauge symmetry. Contrary to expectations, these amplitudes, although mass suppressed, do not vanish in the very high energy limit, but rather become dominant. As a working example we consider a model with two chiral abelian gauge groups U'(1)times U(1) with large mass splitting M(Z') >> M(Z), and we compute leading radiative corrections corrections to the decay of the heavy extra Z' boson into light fermions. The chirality breaking magnetic dipole moment becomes the dominant contribution to the Z' width at very high energies.

  2. Human factors in aviation

    Science.gov (United States)

    Wiener, Earl L. (Editor); Nagel, David C. (Editor)

    1988-01-01

    The fundamental principles of human-factors (HF) analysis for aviation applications are examined in a collection of reviews by leading experts, with an emphasis on recent developments. The aim is to provide information and guidance to the aviation community outside the HF field itself. Topics addressed include the systems approach to HF, system safety considerations, the human senses in flight, information processing, aviation workloads, group interaction and crew performance, flight training and simulation, human error in aviation operations, and aircrew fatigue and circadian rhythms. Also discussed are pilot control; aviation displays; cockpit automation; HF aspects of software interfaces; the design and integration of cockpit-crew systems; and HF issues for airline pilots, general aviation, helicopters, and ATC.

  3. Monocyte chemoattractant protein-1 but not tumor necrosis factor-alpha is correlated with monocyte infiltration in mouse lipid lesions

    Energy Technology Data Exchange (ETDEWEB)

    Reckless, Jill; Rubin, Edward M.; Verstuyft, Judy B.; Metcalfe, James C.; Grainger, David J.

    1999-01-11

    The infiltration of monocytes into the vascular wall and their transformation into lipid-laden foam cells characterize early atherogenesis. This focal accumulation of lipids, together with smooth muscle cell proliferation and migration, and the synthesis of extracellular matrix in the intima of large arteries result in the formation of an atherosclerotic plaque. The extent to which the plaque is infiltrated with monocytes appears to be an important determinant of plaque stability. It has been proposed that macrophages secrete an excess of matrix-degrading enzymes over their inhibitors, resulting in conversion of a stable plaque into anunstable plaque that is likely to rupture, resulting in acutemyocardial infarction. Macrophages and T cells constitute {approx}40 percent of the total population of cells in the lipid core region of atherosclerotic plaques. Their recruitment to the lesion may depend on alterations in the adhesive properties of the endothelial surface. Increased endothelial cell permeability and endothelial cell activation are among the earliest changes associated with developing lesions of atherosclerosis. Many of the cell adhesion molecules involved in monocyte recruitment are expressed at low or undetectable levels on normal endothelium but are substantially elevated on the endothelium overlaying atherosclerotic lesions In addition to endothelial cell activation, numerous chemotactic cytokines have also been postulated to be involved in monocyte recruitment. For example, interleukin (IL)-1 and tumor necrosis factor-a (TNF-a) are direct chemoattractants for human monocytes but additionally induce cytoskeletal changes in the endothelium that result in increased permeability. This increased permeability, together with stimulated expression of adhesion molecules such as E-selectin, plays an important part in the local inflammation mediated by TNF-a and IL-1. In addition, a large number of other proinflammatory cytokines, including macrophage

  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. Neutron quality factor

    International Nuclear Information System (INIS)

    Both the International Commission on Radiological Protection (ICRP) and the National Council on Radiation Protection and Measurements (NCRP) have recommended that the radiation quality weighting factor for neutrons (Qn, or the corresponding new modifying factor, wR) be increased by a value of two for most radiation protection practices. This means an increase in the recommended value for Qn from a nominal value of 10 to a nominal value of 20. This increase may be interpreted to mean that the biological effectiveness of neutrons is two times greater than previously thought. A decision to increase the value of Qn will have a major impact on the regulations and radiation protection programs of Federal agencies responsible for the protection of radiation workers. Therefore, the purposes of this report are: (1) to examine the general concept of open-quotes quality factorclose quotes (Q) in radiation protection and the rationale for the selection of specific values of Qn; and (2) to make such recommendations to the Federal agencies, as appropriate. This report is not intended to be an exhaustive review of the scientific literature on the biological effects of neutrons, with the aim of defending a particular value for Qn. Rather, the working group examined the technical issues surrounding the current recommendations of scientific advisory bodies on this matter, with the aim of determining if these recommendations should be adopted by the Federal agencies. Ultimately, the group concluded that there was no compelling basis for a change in Qn. The report was prepared by Federal scientists working under the auspices of the Science Panel of the Committee on Interagency Radiation Research and Policy Coordination (CIRRPC)

  6. 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.

  7. 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...

  8. What Are the Risk Factors?

    Science.gov (United States)

    ... Links Stay Informed Cancer Home What Are the Risk Factors for Lung Cancer? Language: English Español (Spanish) Recommend ... from your cell phone Research has found several risk factors that may increase your chances of getting lung ...

  9. 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...

  10. 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...

  11. 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...

  12. 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 ...

  13. Services - competitiveness factor of tourism

    OpenAIRE

    Rodica Minciu

    2007-01-01

    Tourism developement reprezent one of the main priority of modern economies. This evolution depends on factor endowements. They correspond to general factor required for the whole economy and to specific factors to the tourism such as certain natural and cultural resources. Factor endowements can be divided into three categories: natural resouces, historic, artistic and cultural heritage, human resources in employment and skills, capital and infrastructure resources. Their economic analysis i...

  14. 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...

  15. Plasma factor XIII and platelet factor XIII in hyperlipaemia.

    Science.gov (United States)

    Cucuianu, M P; Miloszewski, K; Porutiu, D; Losowsky, M S

    1976-12-31

    Plasma factor XIII activity measured by a quantitative assay was found to be significantly higher in hypertriglyceridaemic patients (type IV and combined hyperlipoproteinaemia), as compared to normolipaemic controls. No such elevation in plasma factor XIII activity was found in patients with type Ha hyperlipaemia. Plasma pseudocholinesterase was found to parallel the elevated factor XIII activity in hypertriglyceridaemic subjects. In contrast, platelet factor XIII activity was not raised in hyperlipaemic subjects, and plasma factor XIII was found to be normal in a normolipaemic subjects with thrombocythaemia. It was concluded that there is no significant contribution from platelets to plasma factor XIII activity, and that the observed increase in plasma factor XIII in hypertriglyceridaemia results from enhanced hepatic synthesis of the enzyme. PMID:1037152

  16. 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 ...

  17. 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.

  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. Factor Analysis via Components Analysis

    Science.gov (United States)

    Bentler, Peter M.; de Leeuw, Jan

    2011-01-01

    When the factor analysis model holds, component loadings are linear combinations of factor loadings, and vice versa. This interrelation permits us to define new optimization criteria and estimation methods for exploratory factor analysis. Although this article is primarily conceptual in nature, an illustrative example and a small simulation show…

  20. Factor Analysis of Intern Effectiveness

    Science.gov (United States)

    Womack, Sid T.; Hannah, Shellie Louise; Bell, Columbus David

    2012-01-01

    Four factors in teaching intern effectiveness, as measured by a Praxis III-similar instrument, were found among observational data of teaching interns during the 2010 spring semester. Those factors were lesson planning, teacher/student reflection, fairness & safe environment, and professionalism/efficacy. This factor analysis was as much of a…

  1. Factors influencing the enterprise innovation

    OpenAIRE

    Yachmeneva, V.; Vol’s’ka, G.

    2014-01-01

    The factors that influenced the enterprise innovation are investigated and summarized in the article. Key factors of impact on the enterprise innovation are grouped. Their relationship and mutual influence are proved. Graphic reflect on the impact of external and internal environment factors of the innovative enterprise characteristics are constructed.

  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. [Environmental factors in ALS].

    Science.gov (United States)

    Juntas-Morales, Raul; Pageot, Nicolas; Corcia, Philippe; Camu, William

    2014-05-01

    ALS is likely to be a disorder of multifactorial origin. Among all the factors that may increase the risk of ALS, environmental ones are being studied for many years, but in the recent years, several advances have pointed to a new interest in their potential involvement in the disease process, especially for the cyanotoxin BMAA. Food containing BMAA has been found on Guam, a well-known focus of ALS/parkinsonism/dementia and high levels of BMAA have been identified into the brain of these patients. The BMAA cyanotoxin is potentially ubiquitous and have also been found into the food of patients who died from ALS both in Europe and USA. BMAA can be wrongly integrated into the protein structure during mRNA traduction, competing with serine. This may induce abnormal protein folding and a subsequent cell death. Heavy metals, such as lead or mercury may be directly toxic for neuronal cells. Several works have suggested an increased risk of ALS in individuals chronically exposed to these metals. Exposure to pesticides has been suggested to be linked to an increased risk of developing ALS. The mechanism of their toxicity is likely to be mediated by paraoxonases. These proteins are in charge of detoxifying the organism from toxins, and particularly organophosphates. To date, there are insufficient scientific data to suggest that exposure to electromagnetic fields may increase the risk of having ALS. We are particularly missing longitudinal cohorts to demonstrate that risk. PMID:24703731

  4. Trade, Wages, and Specific Factors

    OpenAIRE

    Indro Dasgupta; Thomas Osang

    2000-01-01

    In this paper, we use a multi-sector specific factors model with sector-specific capital and two mobile factors, production and non-production labor, to examine the effects of globalization on the skill premium in U.S.\\ manufacturing industries. A key feature of this model is that factor-price insensitivity does not hold, and thus endowment changes and factor-specific technological change affect relative factor returns, and hence the skill premium. Using this model and data for the U.S. manuf...

  5. 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.

  6. Prognostic factors of breast cancer

    International Nuclear Information System (INIS)

    The prognostic factors must to be differentiated of the predictive ones. A prognostic factor is any measurement used at moment of the surgery correlated with the free interval of disease or global survival in the absence of the systemic adjuvant treatment and as result is able to correlate with the natural history of the disease. In contrast, a predictive factor is any measurement associated with the response to a given treatment. Among the prognostic factors of the breast cancer are included the clinical, histological, biological, genetic and psychosocial factors. In present review of psychosocial prognostic factors has been demonstrated that the stress and the depression are negative prognostic factors in patients presenting with breast cancer. It is essential to remember that the assessment of just one prognostic parameter is a help but it is not useful to clinical and therapeutic management of the patient.(author)

  7. 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”.

  8. International portfolio diversification: Do industry factors dominate country factors?

    OpenAIRE

    De Moor, Lieven; Sercu, Piet

    2005-01-01

    Despite recent reports to the contrary, we find that even recently-the 1991-2000 period-the country factor still dominates industry influences. This conclusion is robust to different test formats although the relative magnitude of the two sources of variation changes widely. One factor affecting the degree of country-factor dominance is the presence or absence of smallcap stocks in the sample: small-caps have an above average variability (after controlling for industry and country effects) an...

  9. Statistical distribution of factors and factor images in factor analysis of medical image sequences

    International Nuclear Information System (INIS)

    From a time or energy image sequence, factor analysis of medical image sequences (FAMIS) estimates factors, representing kinetics or spectra in a given physiological compartment, and associated factor images, showing the compartments corresponding to each curve. In this paper, we show that the statistical properties of factor images and associated factors can be determined using a well known result from elementary probability theory. Numerical experiments are conducted to demonstrate that the variance observed in factor images can be predicted when the statistical properties of the original data are known. It is shown how these theoretical results can be used to relax the non-negativity constraints during FAMIS oblique analysis and to improve the quantitative interpretation of the factor images by associating a confidence interval with each pixel value. (author)

  10. 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 ...

  11. International Diversification with Factor Funds

    OpenAIRE

    Cheol S. Eun; Sandy Lai; Frans A. de Roon; Zhe Zhang

    2010-01-01

    We propose a new investment strategy employing "factor funds" to systematically enhance the meanvariance efficiency of international diversification. Our approach is motivated by the increasing evidence that size (SMB), book-to-market (HML), and momentum (MOM) factors, along with the market factor, adequately describe international stock returns, and by the direct link between investors' portfolio choice problems and international asset pricing theories and tests. Using data from 10 developed...

  12. Approximate factorization with source terms

    Science.gov (United States)

    Shih, T. I.-P.; Chyu, W. J.

    1991-01-01

    A comparative evaluation is made of three methodologies with a view to that which offers the best approximate factorization error. While two of these methods are found to lead to more efficient algorithms in cases where factors which do not contain source terms can be diagonalized, the third method used generates the lowest approximate factorization error. This method may be preferred when the norms of source terms are large, and transient solutions are of interest.

  13. 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.

  14. 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…

  15. 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

  16. Social networks and factor markets

    DEFF Research Database (Denmark)

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

    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...... sources. These results point out the roles non-market arrangements, such as social networks, can play in mitigating market inefficiencies in poor rural markets....... 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...

  17. 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

  18. Activation of factor VII bound to tissue factor: A key early step in the tissue factor pathway of blood coagulation

    International Nuclear Information System (INIS)

    Whether the factor VII/tissue factor complex that forms in tissue factor-dependent blood coagulation must be activated to factor VIIa/tissue factor before it can activate its substrates, factor X and IX, has been a difficult question to answer because the substrates, once activated, back-activate factor VII. The earlier studies suggested that human factor VII/tissue factor cannot activate factor IX. Studies have now been extended to the activation of factor X. Reaction mixtures were made with purified factor VII, X, and tissue factor; in some experiments antithrombin III and heparin were added to prevent back-activation of factor VII. Factor X was activated at similar rates in reaction mixtures containing either VII or factor VIIa after an initial 30-sec lag with factor VII. In reaction mixtures with factor VII a linear activation of factor X was established several minutes before cleavage of 125I-labeled factor VII to the two-chain activated molecule was demonstrable on gel profiles. These data suggest that factor VII/tissue factor cannot activate measurable amounts of factor X over several minutes. Overall, the results support the hypothesis that a rapid preferential activation of factor VII bound to tissue factor by trace amounts of factor Xa is a key early step in tissue factor-dependent blood coagulation

  19. 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.

  20. 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.

  1. 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)

  2. Shell model and spectroscopic factors

    International Nuclear Information System (INIS)

    In these lectures, I introduce the notion of spectroscopic factor in the shell model context. A brief review is given of the present status of the large scale applications of the Interacting Shell Model. The spectroscopic factors and the spectroscopic strength are discussed for nuclei in the vicinity of magic closures and for deformed nuclei. (author)

  3. 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.

  4. 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....

  5. 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.

  6. Factor Analysis via Components Analysis

    OpenAIRE

    Bentler, Peter M.; Jan de Leeuw

    2011-01-01

    Under the null hypothesis, component loadings are linear combinations of factor loadings, and vice versa. This interrelation permits defining new optimization criteria and estimation methods for exploratory factor analysis. Although this note is primarily conceptual in nature, an illustrative example shows the methodology to be promising.

  7. 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.

  8. 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

  9. 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.

  10. 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...

  11. Physiological enhancement of factors in factor analysis of dynamic studies

    International Nuclear Information System (INIS)

    Factor analysis of dynamic radionuclide studies provides their decomposition into the images and time-activity curves corresponding to the underlying dynamic structures. The method is based on the analysis of study variance and on the subsequent differential imaging of its principal components into a simplified factor space. By changing the amount and the composition of the variance processed in the analysis it is possible to enhance the factors that are important for diagnosis while the less important factors can be suppressed. In our report, a short theoretical review of the problem is given and illustrated by the analysis of dynamic cholescintigraphy. It is shown that a suitable choice of region and/or the temporal interval of interest enables the differential evaluation of such intrahepatic compartments, which could not be observed without enhancement. (orig.)

  12. 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 ...

  13. 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.

  14. 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.)

  15. 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.

  16. 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.

  17. 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. PMID:26027919

  18. Factors Affecting Medical Service Quality.

    Directory of Open Access Journals (Sweden)

    Ali Mohammad Mosadeghrad

    2014-02-01

    Full Text Available A better understanding of factors influencing quality of medical service can pinpoint better strategies for quality assurance in medical services. This study aimed to identify factors affecting the quality of medical services provided by Iranian physicians.Exploratory in-depth individual interviews were conducted with sixty-four physicians working in various medical institutions in Iran.Individual, organizational and environmental factors enhance or inhibit the quality of medical services. Quality of medical services depends on the personal factors of the physician and patient, and factors pertaining to the healthcare setting and the broader environment.Differences in internal and external factors such as availability of resources, patient cooperation and collaboration among providers affect the quality of medical services and patient outcomes. Supportive leadership, proper planning, education and training and effective management of resources and processes improve the quality of medical services. This article contributes to healthcare theory and practice by developing a conceptual framework for understanding factors that influence medical services quality.

  19. 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

  20. Sigma Factors for Cyanobacterial Transcription

    Directory of Open Access Journals (Sweden)

    Sousuke Imamura

    2009-04-01

    Full Text Available Cyanobacteria are photosynthesizing microorganisms that can be used as a model for analyzing gene expression. The expression of genes involves transcription and translation. Transcription is performed by the RNA polymerase (RNAP holoenzyme, comprising a core enzyme and a sigma (σ factor which confers promoter selectivity. The unique structure, expression, and function of cyanobacterial σ factors (and RNAP core subunits are summarized here based on studies, reported previously. The types of promoter recognized by the σ factors are also discussed with regard to transcriptional regulation.

  1. 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.

  2. 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 ...

  3. 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.

  4. 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 ...

  5. 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...

  6. 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 ...

  7. 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...

  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. 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...

  10. Effective Factors on CRM Development

    OpenAIRE

    Fakhraddin Maroofi; Bahareh Moradi Aliabadi; Hooshmand Fakhri; Hadikolivand

    2013-01-01

    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 strateg...

  11. Factors Influencing Healthcare Service Quality

    OpenAIRE

    Ali Mohammad Mosadeghrad

    2014-01-01

    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 o...

  12. 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.

  13. 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...

  14. GATA Transcription Factors and Cancer

    OpenAIRE

    Zheng, Rena; Blobel, Gerd A.

    2010-01-01

    It has been almost a quarter century since it was first appreciated that a class of oncogenes contained in rapidly transforming avian retroviruses encoded DNA-binding transcription factors. As with other oncogenes, genetic recombination with the viral genome led to their overexpression or functional alteration. In the years that followed, alterations of numerous transcription factors were shown to be causatively involved in various cancers in human patients and model organisms. Depending on t...

  15. Factor Specificity and Real Rigidities

    OpenAIRE

    Carlos Viana de Carvalho; Fernanda Feitosa Nechio

    2015-01-01

    We develop a multisector model in which capital and labor are free to move across firms within each sector, but cannot move across sectors. To isolate the role of sectoral specificity, we compare our model with otherwise identical multisector economies with either economy-wide factor markets (as in Chari et al. 2000) or firm-specific factor markets (as in Woodford 2005). Sectoral specificity induces within-sector strategic substitutability and across-sector strategic complementarity in price ...

  16. Power peaking nuclear reliability factors

    International Nuclear Information System (INIS)

    The Calculational Nuclear Reliability Factor (CNRF) assigned to the limiting power density calculated in reactor design has been determined. The CNRF is presented as a function of the relative power density of the fuel assembly and its radial local. In addition, the Measurement Nuclear Reliability Factor (MNRF) for the measured peak hot pellet power in the core has been evaluated. This MNRF is also presented as a function of the relative power density and radial local within the fuel assembly

  17. Factors of trade in Europe

    Czech Academy of Sciences Publication Activity Database

    Hanousek, Jan; Kočenda, Evžen

    2014-01-01

    Roč. 38, č. 4 (2014), s. 518-535. ISSN 0939-3625 R&D Projects: GA ČR(CZ) GAP403/12/0080 Grant ostatní: UK(CZ) UNCE 204005/2012 Institutional support: PRVOUK-P23 Keywords : bilateral trade * factors of trade * panel data Subject RIV: AH - Economics Impact factor: 0.649, year: 2014

  18. 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...

  19. 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

  20. 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.

  1. 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

  2. Ocular Angiogenesis: Vascular Endothelial Growth Factor and Other Factors.

    Science.gov (United States)

    Rubio, Roman G; Adamis, Anthony P

    2016-01-01

    Systematic study of the mechanisms underlying pathological ocular neovascularization has yielded a wealth of knowledge about pro- and anti-angiogenic factors that modulate diseases such as neovascular age-related macular degeneration. The evidence implicating vascular endothelial growth factor (VEGF) in particular has led to the development of a number of approved anti-VEGF therapies. Additional proangiogenic targets that have emerged as potential mediators of ocular neovascularization include hypoxia-inducible factor-1, angiopoietin-2, platelet-derived growth factor-B and components of the alternative complement pathway. As for VEGF, knowledge of these factors has led to a product pipeline of many more novel agents that are in various stages of clinical development in the setting of ocular neovascularization. These agents are represented by a range of drug classes and, in addition to novel small- and large-molecule VEGF inhibitors, include gene therapies, small interfering RNA agents and tyrosine kinase inhibitors. In addition, combination therapy is beginning to emerge as a strategy to improve the efficacy of individual therapies. Thus, a variety of agents, whether administered alone or as adjunctive therapy with agents targeting VEGF, offer the promise of expanding the range of treatments for ocular neovascular diseases. PMID:26502333

  3. 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) ...

  4. Factor intensities and factor substitution in general equilibrium: A Comment

    OpenAIRE

    Nakada, Yoshiaki

    2015-01-01

    Jones and Easton (1983) analyzed how commodity prices affect factor prices in the three-factor two-good general equilibrium trade model. These relationships determine whether ‘a strong Rybczynski result’ holds or not. In subsection 5.2.4., they found that the set of three equations holds for ‘the economy-wide substitution’ under the assumption of ‘perfect complementarity’. And they applied this to their analysis. In the following, I demonstrate that this is impossible, hence their proof is no...

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Some applications of factor analysis

    International Nuclear Information System (INIS)

    The factor analysis is a modern method of statistical analysis of the experimental data. This method applies in a broad range of sciences like psychology, economy, medicine, electronics, physics and other. This method allows one to extract from a set of experimental data some properties of the studied process (usually called 'hidden') when there is not any theoretical description of studied phenomena. In this study we have done a short presentation of factor analysis followed by some applications as the problem of the boxes (the classical one) and the problem of the polynoms. We apply the factor analysis to an ecological problem using a very simple model of the source of pollution (the gaussian one) by simulating the computer data

  10. 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)

  11. 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...

  12. 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.

  13. 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.

  14. 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.

  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. Factores de risco em implantologia

    OpenAIRE

    Sousa, Inês Nunes de

    2015-01-01

    A Implantologia tem ganho popularidade na medicina dentária pelos resultados previsíveis em reabilitações de áreas edêntulas, permitindo minimizar as consequências funcionais, fonéticas e estéticas que advém da perda de dentes através de uma solução fixa que satizfaz os pacientes. Esta é uma revisão da literatura existente sobre factores de risco, fracassos e complicações inerentes ao tratamento com implantes dentários. Categorizam-se os factores de risco em implantologia co...

  17. 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...

  18. 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

  19. 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.

  20. 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.

  1. Human Leptospirosis and risk factors.

    OpenAIRE

    Yanelis Emilia Tabío Henry; Yailín Palmero Dones; Elizabeth Cruz Pérez

    2010-01-01

    The human leptospirosis is a zoonosis of world distribution, were risk factors exist that have favored the wild and domestic animal propagation and so man. A descpitive investigation was made with the objective of determining the behavior of risk factors in outpatients by human leptospirosis in “Camilo Cienfuegos“ University General Hospital from Sncti Spíritus In the comprised time period betwen december 1 st and 3 st , 2008.The sample of this study was conformed by 54 risk persons that kee...

  2. Socio-Cultural Factors and International Competitiveness

    OpenAIRE

    Madara Apsalone; Ērika Šumilo

    2015-01-01

    Socio-cultural factors – shared values, norms and attitudes are significant, but less acknowledged sources of international competitiveness. Previous studies have found socio-cultural factors positively affecting various aspects of international competitiveness – entrepreneurship, innovation, productivity and international cooperation. These factors are more sustainable and less affected by external environment changes in comparison with the traditional factors. Socio-cultural factors provide...

  3. 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...

  4. Binary Factorization by Neural Autoassociators

    Czech Academy of Sciences Publication Activity Database

    Húsek, Dušan; Frolov, A. A.; Muraviev, I.; Řezanková, H.; Snášel, V.; Polyakov, P.Y.

    Zürich : ACTA Press, 2003 - (Hamza, M.), s. 649-653 ISBN 0-88986-390-3. ISSN 1482-7913. [IASTED International Conference /3./. Benalmadena (ES), 08.09.2003-10.09.2003] R&D Projects: GA MŠk LN00B096 Keywords : Boolean factorization * recurrent neural network s * single-step approximation Subject RIV: BD - Theory of Information

  5. 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...

  6. 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.

  7. Factor XIII and adipocyte biology

    OpenAIRE

    Mosher, Deane F.

    2014-01-01

    In this issue of Blood, Myneni et al demonstrate a role for the A (transglutaminase) subunit of factor XIII (FXIII-A) in cell culture models of differentiation of preadipocytes to adipocytes.1 This finding is potentially of great importance in light of recent genome-wide association and adipose tissue transcriptomic studies that implicated F13A1 in human obesity.2

  8. Nutritional factors and hair loss.

    Science.gov (United States)

    Rushton, D H

    2002-07-01

    The literature reveals what little is known about nutritional factors and hair loss. What we do know emanates from studies in protein-energy malnutrition, starvation, and eating disorders. In otherwise healthy individuals, nutritional factors appear to play a role in subjects with persistent increased hair shedding. Hård, 40 years ago, demonstrated the importance of iron supplements in nonanaemic, iron-deficient women with hair loss. Serum ferritin concentrations provide a good assessment of an individual's iron status. Rushton et al. first published data showing that serum ferritin concentrations were a factor in female hair loss and, 10 years later, Kantor et al. confirmed this association. What level of serum ferritin to employ in subjects with increased hair shedding is yet to be definitively established but 70 micro g/L, with a normal erythrocyte sedimentation rate (factors affect the hair directly, one should not forget that they also affect the skin. In the management of subjects with hair loss, eliminating scaling problems is important as is good hair care advice and the need to explain fully the hair cycle. Many individuals reduced their shampooing frequency due to fear of losing more hair but this increases the amount seen in subsequent shampoos fuelling their fear of going bald and adversely affecting their quality of life. PMID:12190640

  9. Human Factor in Therapeutic Relationship

    Directory of Open Access Journals (Sweden)

    Ramazan Akdogan

    2011-03-01

    Full Text Available herapeutic relationship is a professional relationship that has been structured based on theoretical props. This relationship is a complicated, wide and unique relationship which develops between two people, where both sides' personality and attitudes inevitably interfere. Therapist-client relationship experienced through transference and counter transference, especially in psychodynamic approaches, is accepted as the main aspect of therapeutic process. However, the approaches without dynamic/deterministic tendency also take therapist-client relationship into account seriously and stress uniqueness of interaction between two people. Being a person and a human naturally sometimes may negatively influence the relationship between the therapist and client and result in a relationship going out of the theoretical frame at times. As effective components of a therapeutic process, the factors that stem from being human include the unique personalities of the therapist and the client, their values and their attitude either made consciously or subconsciously. Literature has shown that the human-related factors are too effective to be denied in therapeutic relationship process. Ethical and theoretical knowledge can be inefficient to prevent the negative effects of these factors in therapeutic process at which point a deep insight and supervision would have a critical role in continuing an acceptable therapeutic relationship. This review is focused on the reflection of some therapeutic factors resulting from being human and development of counter transference onto the therapeutic process.

  10. 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)

  11. Factors Affecting Nontraditional Vocational Enrollments.

    Science.gov (United States)

    Houser, Betsy Bosak; Garvey, Chris

    This study identifies the internal and external factors which differentiate women who enter male-traditional vocational training programs from those who enter female-traditional programs. Data were collected from 470 women enrolled in California vocational training programs. The sample was stratified on both social class and type of vocational…

  12. 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

  13. Safety culture concept. Human factor

    International Nuclear Information System (INIS)

    The program on analysis and elimination of causes of violating the NPP operation reliability and safety, related to a human factor, is described. The necessity of creating atmosphere of systematic attention to safety problems and personal responsibility for NPPs safety is noted

  14. 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 and...

  15. Introduction to human factors engineering

    International Nuclear Information System (INIS)

    Some of the main aspects of human factors engineering are discussed. The following topics are considered: Integration into the design process; Identification and application of human-centered design requirements; Design of error-tolerant systems; Iterative process consisting of evaluations and feedback loops; Participation of operators/users; Utilization of an interdisciplinary design/ evaluation team; Documentation of the complete HFE-process: traceability

  16. Detecting Risk Factor of Diseases

    Czech Academy of Sciences Publication Activity Database

    Zvárová, Jana

    1995-01-01

    Roč. 15, 1/2 (1995), s. 203-212. ISSN 0208-5216. [Seminar on Statistics and Clinical Practice. Warsaw, 20.06.1994-23.06.1994] Keywords : risk factors * genetics * association * epidemilogy * measures of association * screening * genetics

  17. 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...

  18. Trefoil factors in human milk

    DEFF Research Database (Denmark)

    Vestergaard, Else Marie; Nexø, Ebba; Wendt, A;

    2008-01-01

    We measured concentrations of the gastrointestinal protective peptides Trefoil factors in human milk. By the use of in-house ELISA we detected high amounts of TFF3, less TFF1 and virtually no TFF2 in human breast milk obtained from 46 mothers with infants born extremely preterm (24-27 wk gestation...

  19. 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...

  20. 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

  1. Determining Factors of Subsidiary Development

    DEFF Research Database (Denmark)

    Pedersen, Torben

    . This paper is the first to conduct a statistical test of this model on a large-sample data set including data of more than 2.100 subsidiaries located in seven different countries in Europe. The effect of the three determining factors on subsidiary development is tested simultaneously in a LISREL model....

  2. Physical Factors Influencing Beer Overfoaming

    Czech Academy of Sciences Publication Activity Database

    Novák, Pavel; Vitoušová, K.; Poštulková, Michaela; Brányik, T.; Růžička, Marek

    Vol. Session 1. - : -, 2013, T2:P26. ISBN N. [Conference of European Colloid and Interface Society /27./. Sofia (BG), 01.09.2013-06.09.2013] R&D Projects: GA MŠk(CZ) LD13018 Institutional support: RVO:67985858 Keywords : beer * gushing * physical factors Subject RIV: CI - Industrial Chemistry, Chemical Engineering http://www.ecis2013.org/

  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. Transforming Rubrics Using Factor Analysis

    Science.gov (United States)

    Baryla, Ed; Shelley, Gary; Trainor, William

    2012-01-01

    Student learning and program effectiveness is often assessed using rubrics. While much time and effort may go into their creation, it is equally important to assess how effective and efficient the rubrics actually are in terms of measuring competencies over a number of criteria. This study demonstrates the use of common factor analysis to identify…

  5. Factors in Dubbing Television Comedy.

    Science.gov (United States)

    Zabalbeascoa, Patrick

    1994-01-01

    Advocates a greater awareness of the factors involved with dubbing television comedies. Considers the translation of jokes and provides an outline of the various kinds of jokes in television shows. Calls for more research on comedy dubbing and television translation in general. (HB)

  6. [Psoriasis and cardiovascular risk factors].

    Science.gov (United States)

    Tal, Roy; Pavlovsky, Lev; David, Michael

    2012-10-01

    Psoriasis is a common inflammatory skin disease which may dramatically affect patients' lives. This chronic disease is characterized by a protracted course of alternating remissions and relapses. In recent years, the attention of researchers has focused on the association between psoriasis and cardiovascular disease risk factors. This review summarizes the literature on this topic with an emphasis on research conducted in Israel. PMID:23316664

  7. 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.

  8. 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

  9. 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

  10. 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.)

  11. Food ingestion factors of the Korean exposure factors handbook.

    Science.gov (United States)

    Jang, Jae-Yeon; Jo, Soo-Nam; Kim, Sun-Ja; Myung, Hyung-Nam; Kim, Cho-Il

    2014-01-01

    The purpose of this study was to establish food ingestion factors needed to assess exposure to contaminants through food ingestion. The study reclassified the raw data of the Korean National Health and Nutrition Examination Survey in 2001 into 12 subcategories including grain products, meat products, fish and shellfish, and vegetables for international comparability of exposure evaluation. The criteria for food intake calculation were unified according to the characteristics of food groups, and recommended values for food ingestion factors were calculated through moisture correction and recategorization of cooked, processed, and mixed foods for each group. The average intake rate for grain and grain products was 6.25 g/kg-d per capita and the men's intake rate was approximately 8% higher than that of the women. The average intake rate of meat and meat products was 1.62 g/kg-d per capita and the men's intake rate was 30% higher than that of the women, on average. The average intake rate of fish and shellfish was 1.53 g/kg-d per capita, and the age groups of 1 to 2 and 3 to 6 recorded higher capita intake rates than other age groups, 2.62 g/kg-d and 2.25 g/kg-d, respectively. The average intake rate of vegetables was 6.47 g/kg-d per capita, with the age group of 1 to 2 recording the highest per capita intake rate of 9.79 g/kg-d and that of 13 to 19 recording the lowest mean. The study also offers recommended values for food ingestion factors of other food groups by gender, age, and region. The food ingestion exposure factors will need future updates in consideration of ongoing changes in food consumption behavior. PMID:24570803

  12. Food Ingestion Factors of the Korean Exposure Factors Handbook

    OpenAIRE

    Jang, Jae-Yeon; Jo, Soo-Nam; Kim, Sun-Ja; Myung, Hyung-Nam; Kim, Cho-il

    2014-01-01

    The purpose of this study was to establish food ingestion factors needed to assess exposure to contaminants through food ingestion. The study reclassified the raw data of the Korean National Health and Nutrition Examination Survey in 2001 into 12 subcategories including grain products, meat products, fish and shellfish, and vegetables for international comparability of exposure evaluation. The criteria for food intake calculation were unified according to the characteristics of food groups, a...

  13. 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.

  14. Clearance of von Willebrand factor. : Clearance of von Willebrand factor

    OpenAIRE

    Denis, Cécile; Christophe, Olivier; Oortwijn, Beatrijs,; Lenting, Peter,

    2008-01-01

    The life cycle of von Willebrand factor (VWF) comprises a number of distinct steps, ranging from the controlled expression of the VWF gene in endothelial cells and megakaryocytes to the removal of VWF from the circulation. The various aspects of VWF clearance have been the objects of intense research in the last few years, stimulated by observations that VWF clearance is a relatively common component of the pathogenesis of type 1 von Willebrand disease (VWD). Moreover, improving the survival ...

  15. Sequential coagulation factor VIIa domain binding to tissue factor

    International Nuclear Information System (INIS)

    Vessel wall tissue factor (TF) is exposed to blood upon vascular damage which enables association with factor VIIa (FVIIa). This leads to initiation of the blood coagulation cascade through localization and allosteric induction of FVIIa procoagulant activity. To examine the docking pathway of the FVIIa-TF complex, various residues in the extracellular part of TF (sTF) that are known to interact with FVIIa were replaced with cysteines labelled with a fluorescent probe. By using stopped-flow fluorescence kinetic measurements in combination with surface plasmon resonance analysis, we studied the association of the resulting sTF variants with FVIIa. We found the docking trajectory to be a sequence of events in which the protease domain of FVIIa initiates contact with sTF. Thereafter, the two proteins are tethered via the first epidermal growth factor-like and finally the γ-carboxyglutamic acid (Gla) domain. The two labelled sTF residues interacting with the protease domain of FVIIa bind or become eventually ordered at different rates, revealing kinetic details pertinent to the allosteric activation of FVIIa by sTF. Moreover, when the Gla domain of FVIIa is removed the difference in the rate of association for the remaining domains is much more pronounced

  16. 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 ...

  17. 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 ...

  18. Order-preserving factor analysis (OPFA)

    OpenAIRE

    Puig, Arnau Tibau; Hero III, Alfred O.

    2011-01-01

    We present a novel factor analysis method that can be applied to the discovery of common factors shared among trajectories in multivariate time series data. These factors satisfy a precedence-ordering property: certain factors are recruited only after some other factors are activated. Precedence-ordering arise in applications where variables are activated in a specific order, which is unknown. The proposed method is based on a linear model that accounts for each factor's inherent delays and r...

  19. 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...

  20. 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.

  1. International Trade, Factor Mobility and Trade Costs

    OpenAIRE

    Norman, Victor D; Venables, Anthony J.

    1993-01-01

    We consider a Heckscher-Ohlin model in which goods and factors of production can be traded, but trade involves transactions costs. Goods trade alone will not equalize factor prices, so there is an incentive for trade in factors of production. Whether goods or factors are traded depends on endowments and transactions costs. We characterize equilibria in which there is no trade, there is goods trade only, there is factor trade only, and there is trade in both goods and factors. This generalizes...

  2. 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

  3. [Prognostic factors in hantavirus infections].

    Science.gov (United States)

    Kaya, Selçuk

    2014-01-01

    The hantaviruses classified in Hantavirus genus of Bunyaviridae family, may cause two different types of clinical conditions, namely hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS). Mortality may reach up to 40% in these infections. Hantavirus subtypes (Sin Nombre, Hantaan, Seoul, Puumala, Dobrava, etc) with different virulences represent one of the most significant factors affecting the mortality. Additionally, many other factors including age, gender, humoral immune response, genetic factors, patient's clinical and laboratory findings, transfusion, mechanical ventilation requirement, antiviral treatment and immunotherapy administered to the patient are prognostically important. Increasing age had an unfavorable effect on mortality. While the disease is commonly observed in the male gender, mortality rate is higher in the female gender. The higher the emergent neutralizing antibody response, the virus spread, the number of the infected cells and the cytotoxic T lymphocyte-mediated injury will be lower. The requirement for dialysis is reported to be higher with a poorer prognosis in individuals with HLA-B8, -DR3, -DQ2 alleles, and those with HLA-B27 allele usually experience a milder clinical course. Clinically, the risk of mortality increases in patients with multiple, central nervous system hemorrhage, sepsis, disseminated intravascular coagulation (DIC) and secondary infection. The presence of adult respiratory distress syndrome (ARDS), the requirement for mechanical ventilation, the presence of dyspnea and hemoconcentration in HPS are reported to be the most important prognostic factors associated with death. The correlation of severity and the transfusion requirement with mortality was demonstrated. High serum levels of white blood cells, blood urea nitrogen (BUN), creatinine phophokinase (CPK), C-reactive protein (CRP), prothrombin time (PT), activated partial thromboplastin time (aPTT), D-dimer and INR (International

  4. 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

  5. Individual Factors and Knowledge Sharing

    Directory of Open Access Journals (Sweden)

    Eugene Okyere-Kwakye

    2011-01-01

    Full Text Available Problem statement: Knowledge management has been acknowledged as an important element for businesses today. While individuals within the organizations might recognize the importance of knowledge management for the success of their day to day business functions, previous literatures have shown that individuals are still reluctant to participate in knowledge management efforts especially knowledge sharing. As the behavior people show in different situations depends highly on their personal intentions as well as the social forces, the degree of the reluctance or willingness towards sharing their knowledge might also fit in the same case. Based on previous studies we develop a conceptual framework to suggest a relationship between knowledge sharing and four of the individual factors namely altruism, self efficacy, mutual reciprocity and trust. Questionnaire is proposed to collect data and multiple regressions as the statistical technique to analyze the data. Conclusion/Recommendations: This study makes an attempt to discuss some of the individual factors that can affect knowledge sharing.

  6. 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.

  7. 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.

  8. 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

  9. 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

  10. 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)

  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. The analytic pion form factor

    CERN Document Server

    Lomon, Earle L

    2016-01-01

    The pion electromagnetic form factor and two-pion production in electron-positron collisions are simultaneously fitted by a vector dominance model evolving to perturbative QCD at large momentum transfer. This model was previously successful in simultaneously fitting the nucleon electromagnetic form factors (space-like region) and the electromagnetic production of nucleon-antinucleon pairs (time-like region). For this pion case dispersion relations are used to produce the analytic connection of the space-like and time-like regions. The fit to all the data is good. The description of high-$q^2$ data, in the time-like region, requires one more meson with $\\rho$ quantum numbers than listed in the 2014 Particle Data Group review.

  13. 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.

  14. Factors influencing wind energy curtailment

    OpenAIRE

    Burke, Daniel J.; O'MALLEY, MARK, J.

    2011-01-01

    Nonphysically firm wind generation connections (i.e., those to which curtailment can apply) may be necessary for significant wind integration to congested transmission networks. A study of factors influencing this associated wind energy curtailment is, therefore, of timely importance. In this paper, the wind curtailment estimation effects of natural inter-yearly wind profile variability, system demand-profile/fuel-price parameter uncertainty, and minimum system inertial constraints are studie...

  15. 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.

  16. Portfolio diversification using subspace factorizations

    OpenAIRE

    de Fréin, Ruairí; Drakakis, Konstantinos; Rickard, Scott

    2008-01-01

    Successful investment management relies on allocating assets so as to beat the stock market. Asset classes are affected by different market dynamics or latent trends. These interactions are crucial to the successful allocation of monies. The seminal work on portfolio management by Markowitz prompts the adroit investment manager to consider the correlation between the assets in his portfolio and to vary his selection so as to optimize his riskreturn profile. The factor mod...

  17. 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...

  18. Market Volatility and Macroeconomic Factors

    OpenAIRE

    Gao, Kang

    2012-01-01

    This study investigates the relationship between macroeconomic factors and the stock market volatility. Following macroeconomic variables are used: industrial production, inflation rate, interest rate and exchange rate. Shanghai Exchange Composite Index, Standard & Poor’s 500, FTSE 100 and Deutscher Aktien Index are chosen to represent the China, United States, United Kingdom and Germany market. Monthly time series data of mentioned variables are the time period is from November 2001 to April...

  19. Insomnia: prevalence and associated factors

    OpenAIRE

    Lopes, Cátia; Lopes, Daniela; Ferreira, Sofia; Correia, Teresa; Pinto, Isabel C.

    2014-01-01

    Nowadays sleep disorders are very common and affect most of the population, the most common may be insomnia. Insomnia is defined as the difficulty of initiating or maintaining sleep it, may also be reflected in an early wake up and by the presence of a non-restful sleep and it is associated with impairment in social and occupational functioning of the individual. Knowing the prevalence and the associated factors of insomnia. This is a cross-sectional epidemiological study. The pop...

  20. CCCTB - The Employment Factor Game

    OpenAIRE

    Eberhartinger, Eva; Petutschnig, Matthias

    2014-01-01

    The draft for a Common Consolidated Corporate Tax Base Directive in the European Union includes the suggestion for an apportionment formula which allocates taxable group profits to group member corporations. These allocated profits shall then be taxed in the respective Member States. The draft directive delegates the right to define one factor of the apportionment formula, the term "Employee" to the Member States, who are therefore free to choose a narrow or a broad definition,...

  1. Social Factors and Preference Change

    DEFF Research Database (Denmark)

    Campbell-Meiklejohn, Daniel; Frith, Chris D

    2012-01-01

    Humans are intensely social animals. Much of our behavior is enacted in the presence, and during interactions, with others. We should not be surprised at the extent to which others influence our decisions and values. As Adam Smith suggested (1759), obtaining money (i.e. resources) may not be the ...... our individual behavior (without our awareness) and explicit social factors that play a crucial role in enabling our collaborations with others to achieve more than the sum of the individuals involved....

  2. Childhood asthma and risk factors

    OpenAIRE

    Ljuština-Pribić Radmila; Petrović Slobodanka; Tomić Jelena

    2010-01-01

    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 epidemio...

  3. 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

  4. 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.

  5. Common Factors in Return Seasonalities

    OpenAIRE

    Matti Keloharju; Juhani T. Linnainmaa; Peter Nyberg

    2014-01-01

    A strategy that selects stocks based on their historical same-calendar-month returns earns an average return of 13% per year. We document similar return seasonalities in anomalies, commodities, international stock market indices, and at the daily frequency. The seasonalities overwhelm unconditional differences in expected returns. The correlations between different seasonality strategies are modest, suggesting that they emanate from different common factors. Our results suggest that seasonali...

  6. Two Factor Authentication Made Easy

    OpenAIRE

    Chen, Alex Q. and Goh, Weihan

    2015-01-01

    Authentication on the Web is a challenge that can have a negative effect on user experience if it becomes overly complicated and cumbersome. This experience is even more crucial for older and visually impaired users due to their functional abilities. Web applications typically authenticate users by requesting for information that only the user knows (e.g. password). To enhance security, two-factor authentication (2FA) are increasingly implemented, which require the user to manually transfer i...

  7. 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.

  8. 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.

  9. 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.

  10. 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...

  11. Antiretroviral Restriction Factors in Mice

    OpenAIRE

    Nair, Smita; Rein, Alan

    2014-01-01

    One of the most exciting areas in contemporary retrovirus research is the discovery of “restriction factors”. These are cellular proteins that act after virus entry to inhibit infection by or replication of retroviruses (and other viruses and intracellular pathogens). We briefly discuss here three antiretroviral restriction factors in mice: Fv1, APOBEC3, and tetherin, touching on both biological and molecular aspects of these restriction systems.

  12. 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...

  13. 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

  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. 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

  16. Factorizing the time evolution operator

    International Nuclear Information System (INIS)

    There is a widespread belief in the quantum physical community, and textbooks used to teach quantum mechanics, that it is a difficult task to apply the time evolution operator eitH-hat/h on an initial wavefunction. Because the Hamiltonian operator is, generally, the sum of two operators, then it is not possible to apply the time evolution operator on an initial wavefunction ψ(x, 0), for it implies using terms like (a-hat + b-hat). A possible solution is to factorize the time evolution operator and then apply successively the individual exponential operator on the initial wavefunction. However, the exponential operator does not directly factorize, i.e. ea-hat+b-hat ≠ ea-hat eb-hat. In this study we present a useful procedure for factorizing the time evolution operator when the argument of the exponential is a sum of two operators, which obey specific commutation relations. Then, we apply the exponential operator as an evolution operator for the case of elementary unidimensional potentials, like a particle subject to a constant force and a harmonic oscillator. Also, we discuss an apparent paradox concerning the time evolution operator and non-spreading wave packets addressed previously in the literature

  17. Factorizing the time evolution operator

    CERN Document Server

    Quijas, P C G

    2006-01-01

    There is a widespread belief in the quantum physical community, and in textbooks used to teach Quantum Mechanics, that it is a difficult task to apply the time evolution operator on an initial wave function. That is to say, because the hamiltonian operator generally is the sum of two operators, then it is a difficult task to apply the time evolution operator on an initial wave function, because it implies to apply terms like (A+B)^n. A possible solution of this problem is to factorize the time evolution operator and then apply successively the individual exponential operator on the initial wave function. However, the exponential operator does not directly factorize. In this work we present useful ways to factorizing the time evolution operator when the argument of the exponential is a sum of two operators which obey specific commutation relations. Then, we apply the exponential operator as an evolution operator for the case of elementary unidimensional potentials, like the harmonic oscillator. Also, we argue ...

  18. 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...

  19. Cardiac risk factors: environmental, sociodemographic, and behavioral cardiovascular risk factors.

    Science.gov (United States)

    Anthony, David; George, Paul; Eaton, Charles B

    2014-06-01

    Several environmental exposures are associated with increased risk of coronary heart disease (CHD). Exposure to secondhand smoke may increase the risk by as much as 25% to 30%. Exposure to third hand smoke, residual components of tobacco smoke that remain in the environment after a cigarette is extinguished, also appears to increase risk. These residual components can remain in rooms and automobiles for up to 30 years and enter the body through the skin or via inhalation or ingestion. Exposure to particulate matter air pollution from automobile emissions, power plants, and other sources is yet another environmental risk factor for CHD, resulting in tens of thousands of deaths annually in the United States. Exposure to other environmental toxins, particularly bisphenol A and phthalates, also has been linked to CHD. There are sociodemographic risks for CHD, with numerous studies showing that lower socioeconomic status is associated with higher risk. Behavioral risk factors include poor diet, such as frequent consumption of fast food and processed meals; sleep disturbance; and psychological stress, particularly related to marital or work issues. Finally, although high alcohol consumption is associated with increased CHD risk, moderate alcohol consumption (ie, less than 1 to 2 drinks/day), particularly of wine and possibly beer, appears to reduce the risk. PMID:24936715

  20. 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