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Sample records for cd95 death-inducing signaling

  1. Yes and PI3K bind CD95 to signal invasion of glioblastoma.

    Science.gov (United States)

    Kleber, Susanne; Sancho-Martinez, Ignacio; Wiestler, Benedict; Beisel, Alexandra; Gieffers, Christian; Hill, Oliver; Thiemann, Meinolf; Mueller, Wolf; Sykora, Jaromir; Kuhn, Andreas; Schreglmann, Nina; Letellier, Elisabeth; Zuliani, Cecilia; Klussmann, Stefan; Teodorczyk, Marcin; Gröne, Hermann-Josef; Ganten, Tom M; Sültmann, Holger; Tüttenberg, Jochen; von Deimling, Andreas; Regnier-Vigouroux, Anne; Herold-Mende, Christel; Martin-Villalba, Ana

    2008-03-01

    Invasion of surrounding brain tissue by isolated tumor cells represents one of the main obstacles to a curative therapy of glioblastoma multiforme. Here we unravel a mechanism regulating glioma infiltration. Tumor interaction with the surrounding brain tissue induces CD95 Ligand expression. Binding of CD95 Ligand to CD95 on glioblastoma cells recruits the Src family member Yes and the p85 subunit of phosphatidylinositol 3-kinase to CD95, which signal invasion via the glycogen synthase kinase 3-beta pathway and subsequent expression of matrix metalloproteinases. In a murine syngeneic model of intracranial GBM, neutralization of CD95 activity dramatically reduced the number of invading cells. Our results uncover CD95 as an activator of PI3K and, most importantly, as a crucial trigger of basal invasion of glioblastoma in vivo. PMID:18328427

  2. Physalis peruviana extract induces apoptosis in human Hep G2 cells through CD95/CD95L system and the mitochondrial signaling transduction pathway.

    Science.gov (United States)

    Wu, Shu-Jing; Ng, Lean-Teik; Lin, Doung-Liang; Huang, Shan-Ney; Wang, Shyh-Shyan; Lin, Chun-Ching

    2004-11-25

    Physalis species is a popular folk medicine used for treating cancer, leukemia, hepatitis and other diseases. Studies have shown that the ethanol extract of Physalis peruviana (EEPP) inhibits growth and induces apoptotic death of human Hep G2 cells in culture, whereas proliferation of the mouse BALB/C normal liver cells was not affected. In this study, we performed detailed studies to define the molecular mechanism of EEPP-induced apoptosis in Hep G2 cells. The results further confirmed that EEPP inhibited cell proliferation in a dose- and time-dependent manner. At 50 microg/ml, EEPP significantly increased the accumulation of the sub-G1 peak (hypoploid) and the portion of apoptotic annexin V positive cells. EEPP was found to trigger apoptosis through the release of cytochrome c, Smac/DIABLO and Omi/HtrA2 from mitochondria to cytosol and consequently resulted in caspase-3 activation. Pre-treatment with a general caspase inhibitor (z-VAD-fmk) prevented cytochrome c release. After 48 h of EEPP treatment, the apoptosis of Hep G2 cells was found to associate with an elevated p53, and CD95 and CD95L proteins expression. Furthermore, a marked down-regulation of the expression of the Bcl-2, Bcl-XL and XIAP, and up-regulation of the Bax and Bad proteins were noted. Taken together, the present results suggest that EEPP-induced Hep G2 cell apoptosis was possibly mediated through the CD95/CD95L system and the mitochondrial signaling transduction pathway. PMID:15488639

  3. CD95-Mediated Calcium Signaling Promotes T Helper 17 Trafficking to Inflamed Organs in Lupus-Prone Mice.

    Science.gov (United States)

    Poissonnier, Amanda; Sanséau, Doriane; Le Gallo, Matthieu; Malleter, Marine; Levoin, Nicolas; Viel, Roselyne; Morere, Lucie; Penna, Aubin; Blanco, Patrick; Dupuy, Alain; Poizeau, Florence; Fautrel, Alain; Seneschal, Julien; Jouan, Florence; Ritz, Jerome; Forcade, Edouard; Rioux, Nathalie; Contin-Bordes, Cécile; Ducret, Thomas; Vacher, Anne-Marie; Barrow, Paul A; Flynn, Robin J; Vacher, Pierre; Legembre, Patrick

    2016-07-19

    CD95 ligand (CD95L) is expressed by immune cells and triggers apoptotic death. Metalloprotease-cleaved CD95L (cl-CD95L) is released into the bloodstream but does not trigger apoptotic signaling. Hence, the pathophysiological role of cl-CD95L remains unclear. We observed that skin-derived endothelial cells from systemic lupus erythematosus (SLE) patients expressed CD95L and that after cleavage, cl-CD95L promoted T helper 17 (Th17) lymphocyte transmigration across the endothelial barrier at the expense of T regulatory cells. T cell migration relied on a direct interaction between the CD95 domain called calcium-inducing domain (CID) and the Src homology 3 domain of phospholipase Cγ1. Th17 cells stimulated with cl-CD95L produced sphingosine-1-phosphate (S1P), which promoted endothelial transmigration by activating the S1P receptor 3. We generated a cell-penetrating CID peptide that prevented Th17 cell transmigration and alleviated clinical symptoms in lupus mice. Therefore, neutralizing the CD95 non-apoptotic signaling pathway could be an attractive therapeutic approach for SLE treatment. PMID:27438772

  4. Lipid rafts and raft-mediated supramolecular entities in the regulation of CD95 death receptor apoptotic signaling.

    Science.gov (United States)

    Gajate, Consuelo; Mollinedo, Faustino

    2015-05-01

    Membrane lipid rafts are highly ordered membrane domains enriched in cholesterol, sphingolipids and gangliosides that have the property to segregate and concentrate proteins. Lipid and protein composition of lipid rafts differs from that of the surrounding membrane, thus providing sorting platforms and hubs for signal transduction molecules, including CD95 death receptor-mediated signaling. CD95 can be recruited to rafts in a reversible way through S-palmitoylation following activation of cells with its physiological cognate ligand as well as with a wide variety of inducers, including several antitumor drugs through ligand-independent intracellular mechanisms. CD95 translocation to rafts can be modulated pharmacologically, thus becoming a target for the treatment of apoptosis-defective diseases, such as cancer. CD95-mediated signaling largely depends on protein-protein interactions, and the recruitment and concentration of CD95 and distinct downstream apoptotic molecules in membrane raft domains, forming raft-based supramolecular entities that act as hubs for apoptotic signaling molecules, favors the generation and amplification of apoptotic signals. Efficient CD95-mediated apoptosis involves CD95 and raft internalization, as well as the involvement of different subcellular organelles. In this review, we briefly summarize and discuss the involvement of lipid rafts in the regulation of CD95-mediated apoptosis that may provide a new avenue for cancer therapy.

  5. Lipid raft-mediated Fas/CD95 apoptotic signaling in leukemic cells and normal leukocytes and therapeutic implications.

    Science.gov (United States)

    Gajate, Consuelo; Mollinedo, Faustino

    2015-11-01

    Plasma membrane is now recognized to contain tightly packed cholesterol/sphingolipid-rich domains, known as lipid or membrane rafts, which are more ordered than the surrounding lipid bilayer. Lipid rafts are crucial for the compartmentalization of signaling processes in the membrane, mostly involved in cell survival and immune response. However, in the last 15 years, a large body of evidence has also identified raft platforms as scaffolds for the recruitment and clustering of death receptor Fas/CD95 and downstream signaling molecules, leading to the concept of death-promoting lipid rafts. This raft-Fas/CD95 coclustering was first described at the early 2000s as the underlying mechanism for the proapoptotic action of the alkylphospholipid analog edelfosine in leukemic cells, hence facilitating protein-protein interactions and conveying apoptotic signals independently of Fas/CD95 ligand. Edelfosine induces apoptosis in hematologic cancer cells and activated T-lymphocytes. Fas/CD95 raft coclustering is also promoted by Fas/CD95 ligand, agonistic Fas/CD95 antibodies, and additional antitumor drugs. Thus, death receptor recruitment in rafts is a physiologic process leading to cell demise that can be pharmacologically modulated. This redistribution and local accumulation of apoptotic molecules in membrane rafts, which are usually accompanied by displacement of survival signaling molecules, highlight how alterations in the apoptosis/survival signaling balance in specialized membrane regions modulate cell fate. Membrane rafts might also modulate apoptotic and nonapoptotic death receptor signaling. Here, we discuss the role of lipid rafts in Fas/CD95-mediated apoptotic cell signaling in hematologic cancer cells and normal leukocytes, with a special emphasis on their involvement as putative therapeutic targets in cancer and autoimmune diseases.

  6. Cytoplasmic Overexpression of CD95L in Esophageal Adenocarcinoma Cells Overcomes Resistance to CD95-Mediated Apoptosis

    Directory of Open Access Journals (Sweden)

    Gregory A. Watson

    2011-03-01

    Full Text Available Introduction: The CD95/CD95L pathway plays a critical role in tissue homeostasis and immune system regulation; however, the function of this pathway in malignancy remains poorly understood. We hypothesized that CD95L expression in esophageal adenocarcinoma confers advantages to the neoplasm other than immune privilege. Methods: CD95L expression was characterized in immortalized squamous esophagus (HET-1A and Barrett esophagus (BAR-T cells; adenocarcinoma cell lines FLO-1, SEG-1, and BIC-1, and MDA468 (- control; and KFL cells (+ control. Analyses included reverse transcription-polymerase chain reaction, immunoblots of whole cell and secretory vesicle lysates, FACScan analysis, laser scanning confocal microscopy of native proteins and fluorescent constructs, and assessment of apoptosis and ERK1/2 pathways. Results: Cleaved, soluble CD95L is expressed at both the RNA and protein levels in these cell lines derived from esophageal adenocarcinoma and other human tissues. CD95L was neither trafficked to the cell membrane nor secreted into the media or within vesicles, rather the protein seems to be sequestered in the cytoplasm. CD95 and CD95L colocalize by immunofluorescence, but an interaction was not proven by immunoprecipitation. Overexpression of CD95L in the adenocarcinoma cell lines induced robust apoptosis and, under conditions of pan-caspase inhibition, resulted in activation of ERK signaling. Conclusions: CD95L localization in EA cells is inconsistent with the conference of immune privilege and is more consistent with a function that promotes tumor growth through alternative CD95 signaling. Reduced cell surface expression of CD95 affects cell sensitivity to extracellular apoptotic signals more significantly than alterations in downstream modulators of apoptosis.

  7. Cucurbitacin E Induces G2/M Phase Arrest through STAT3/p53/p21 Signaling and Provokes Apoptosis via Fas/CD95 and Mitochondria-Dependent Pathways in Human Bladder Cancer T24 Cells

    Directory of Open Access Journals (Sweden)

    Wen-Wen Huang

    2012-01-01

    Full Text Available Cucurbitacin E, a tetracyclic triterpenes compound extracted from cucurbitaceous plants, has been shown to exhibit anticancer and anti-inflammatory activities. The purpose of this study was to elucidate whether cucurbitacin E promotes cell cycle arrest and induces apoptosis in T24 cells and further to explore the underlying molecular mechanisms. The effects of cucurbitacin E on T24 cell's growth and accompanied morphological changes were examined by MTT assay and a phase-contrast microscope. DNA content, mitochondrial membrane potential (ΔΨm and annexin V/PI staining were determined by flow cytometry. The protein levels were measured by Western blotting. Our results demonstrated that cucurbitacin E-induced G2/M arrest was associated with a marked increase in the levels of p53, p21 and a decrease in phospho-signal transducer and activator of transcription 3 (STAT3, cyclin-dependent kinase 1 (CDK1 and cyclin B. Cucurbitacin E-triggered apoptosis was accompanied with up-regulation of Fas/CD95, truncated BID (t-BID and a loss of ΔΨm, resulting in the releases of cytochrome c, apoptotic protease activating factor 1 (Apaf-1 and apoptosis-inducing factor (AIF, and sequential activation of caspase-8, caspase-9, and caspase-3. Our findings provided the first evidence that STAT3/p53/p21 signaling, Fas/CD95 and mitochondria-dependent pathways play critical roles in cucurbitacin E-induced G2/M phase arrest and apoptosis of T24 cells.

  8. Correlation of CD95 and soluble CD95 expression with acute rejection status of liver transplantation

    Institute of Scientific and Technical Information of China (English)

    Yu-Liang Wang; Yan-Yan Zhang; Guang Li; Zhi-Qin Tang; Yan-Li Zhou; Zhi-Jun Zhu; Zhi Yao

    2005-01-01

    AIM: To analyze the expression levels of soluble form of CD95, CD95 ligand (sCD95 and sCD95L, respectively) in plasma and CD95 expression on CD3+ cells in livertransplanted recipients with acute rejection (AR).METHODS: Peripheral blood mononuclear cells (PBMCs)were isolated from 30 clinically liver transplanted recipients.CD95 expression on CD3+ cells was quantitatively measured by two-color fluorescence activated cell sorter (FACS)analysis. Lymphocyte surface phenotypes of CD4, CD8,CD16 and CD55 were determined by flow cytometry.Plasma levels of sCD95 and sCD95L were detected byEnzyme Linked-Immuno-Sorbent Assay (ELISA). The results were compared with that from normal healthy volunteers (n = 15 individuals).RESULTS: FACS analysis showed that CD95 expression on CD3+ T cells was significantly increased in liver transplanted recipients with AR compared to that in stable recipients without rejection and infection or healthy individuals who did not undergo transplantation (18 676.93±11 588.34/molecule,6 848.20±1712.96/molecule, 6 418.01±2 001.95/molecule,respectively, P<0.01). Whereas no significant difference was seen between liver-transplanted stable recipients and healthy individuals. Furthermore, no significant differences were detected between each group with CD4/CD8 ratio or the percentage of CD16+56+ cells. Plasma levels of sCD95were significantly higher in transplanted recipients with AR compered to that in stable recipients or healthy individuals (391.88±196.00, 201.37±30.30, 148.83±58.25 pg/mL,respectively, P<0.01). In contrast, the plasma levels ofsCD95L in liver- transplanted recipients were not significantlydifferent from that in healthy individuals.CONCLUSION: The present results indicate that the increased CD95 expression on CD3+ cells and the increased levels of sCD95 in plasma may modify the immunological situation of the recipients after transplantation or represent the ongoing graft rejection.

  9. CD95-CD95L: can the brain learn from the immune system?

    DEFF Research Database (Denmark)

    Becher, B; Barker, P A; Owens, T;

    1998-01-01

    ), was initially identified in the immune system and has been shown to mediate receptor-dependent programmed cell death and to be expressed in the nervous system. In neurodegenerative disorders, CD95-CD95 ligand expression on glial cells might precede receptor-mediated apoptosis by cells of the CNS. It is now...... these divergent effects and utilize such knowledge to aid understanding of cell death and survival....

  10. Docosahexaenoic acid counteracts attenuation of CD95-induced cell death by inorganic mercury

    International Nuclear Information System (INIS)

    In the United States the principal environmental exposure to mercury is through dietary consumption of sea food. Although the mechanism by which low levels of mercury affect the nervous system is not well established, epidemiological studies suggest that low level exposure of pregnant women to dietary mercury can adversely impact cognitive development in their children, but that Docosahexaenoic acid (DHA), the most prominent n-polyunsaturated fatty acid (n-PUFA) present in fish may counteract negative effects of mercury on the nervous system. Aside from effects on the nervous system, epidemiological and animal studies have also suggested that low level mercury exposure may be a risk factor for autoimmune disease. However unlike the nervous system where a mechanism linking mercury to impaired cognitive development remains elusive, we have previously suggested a potential mechanism linking low level mercury exposures to immune system dysfunction and autoimmunity. In the immune system it is well established that disruption of CD95 mediated apoptosis leads to autoimmune disease. We have previously shown in vitro as well as in vivo that in lymphocytes burdened with low levels of mercury, CD95 mediated cell death is impaired. In this report we now show that DHA counteracts the negative effect of mercury on CD95 signaling in T lymphocytes. T cells which have been pre-exposed to DHA are able to cleave pro-caspase 3 and efficiently signal programmed cell death through the CD95 signaling pathway, whether or not they are burdened with low levels of mercury. Thus DHA may lower the risk of autoimmune disease after low level mercury exposures. - Highlights: • Inorganic mercury (Hg2+) interferes with CD95 mediated cell death in Jurkat T cells • DHA restores the ability of CD95 to signal cell death in Hg2+ intoxicated T cells • The restoration of CD95 mediated cell death by DHA is correlated with increased activation of Caspase 3

  11. Docosahexaenoic acid counteracts attenuation of CD95-induced cell death by inorganic mercury

    Energy Technology Data Exchange (ETDEWEB)

    Gill, Randall [Department of Immunology and Microbiology, Wayne State University, Detroit MI (United States); Lanni, Lydia; Jen, K.-L. Catherine [Department of Nutrition and Food Science, Wayne State University, Detroit MI (United States); McCabe, Michael J. [Department of Environmental Medicine, University of Rochester, Rochester NY (United States); Rosenspire, Allen, E-mail: arosenspire@wayne.edu [Department of Immunology and Microbiology, Wayne State University, Detroit MI (United States)

    2015-01-01

    In the United States the principal environmental exposure to mercury is through dietary consumption of sea food. Although the mechanism by which low levels of mercury affect the nervous system is not well established, epidemiological studies suggest that low level exposure of pregnant women to dietary mercury can adversely impact cognitive development in their children, but that Docosahexaenoic acid (DHA), the most prominent n-polyunsaturated fatty acid (n-PUFA) present in fish may counteract negative effects of mercury on the nervous system. Aside from effects on the nervous system, epidemiological and animal studies have also suggested that low level mercury exposure may be a risk factor for autoimmune disease. However unlike the nervous system where a mechanism linking mercury to impaired cognitive development remains elusive, we have previously suggested a potential mechanism linking low level mercury exposures to immune system dysfunction and autoimmunity. In the immune system it is well established that disruption of CD95 mediated apoptosis leads to autoimmune disease. We have previously shown in vitro as well as in vivo that in lymphocytes burdened with low levels of mercury, CD95 mediated cell death is impaired. In this report we now show that DHA counteracts the negative effect of mercury on CD95 signaling in T lymphocytes. T cells which have been pre-exposed to DHA are able to cleave pro-caspase 3 and efficiently signal programmed cell death through the CD95 signaling pathway, whether or not they are burdened with low levels of mercury. Thus DHA may lower the risk of autoimmune disease after low level mercury exposures. - Highlights: • Inorganic mercury (Hg{sup 2+}) interferes with CD95 mediated cell death in Jurkat T cells • DHA restores the ability of CD95 to signal cell death in Hg{sup 2+} intoxicated T cells • The restoration of CD95 mediated cell death by DHA is correlated with increased activation of Caspase 3.

  12. Interference of CD95 expression on human lymphocytes.

    Science.gov (United States)

    Petanova, Jitka; Fucikova, Terezie; Bencko, Vladimir

    2002-02-01

    The study presents the exogenous influence of cadmium in comparison with zinc on the apoptosis of human lymphocytes by CD95 expression and its kinetic changes. The salts of both metals were used in final concentrations of 20 microM in cell cultures with whole blood. The duration of cultivation was 18 and 90 hours. The expression of surface antigens was evaluated by flow cytometry with monoclonal antibodies. In cultures of not stimulated cells we found in average 51.54% CD95 positive lymphocytes. The kinetic study of untreated cells showed elevation after 18 hours of cultivation and a very low expression after 90 hours. The CD95 expression on lymphocytes in cell culture with cadmium and zinc was lower after 18 hours of cultivation than in untreated cells. After 90 hours cultivation we found low levels of CD95 expression on cells treated with cadmium and a great individual variability in the number of positive cells upon the influence of zinc.

  13. Parameter identification using stochastic simulations reveals a robustness in CD95 apoptotic response.

    Science.gov (United States)

    Zimmer, Christoph; Schleich, Kolja; Lavrik, Inna

    2016-04-26

    A number of mathematical models of apoptosis generated recently allowed us to understand intrinsic mechanisms of life/death decisions in a cell. Nevertheless, the parameters for the mathematical models are often experimentally difficult to obtain and there is an emerging need for the development of efficient approaches for parameter estimation. In this study we suggest a new method for parameter estimation, which is based on stochastic simulations and can be used when the number of molecules in the system is small. Our approach comprised the following steps: we start from the selection of parameters that lead to a good ordinary differential equation (ODE) fit. We continued by carrying out stochastic simulations for each of these parameters. Comparing the correlation structure of these simulations with the data, we finally could identify the best parameter set. The method was applied for a model of CD95-induced apoptosis, the new best identified parameters fit well to the experimental data. The best parameter set allowed us to get new insights into CD95 apoptosis regulation and can be applied for the comprehensive analysis of other signaling networks. The modeling approach allowed us to get new insights into network regulation, in particular, to identify robustness in CD95 apoptotic response. Taken together, this new method provides valuable predictions and can be applied for the analysis of other signaling networks. PMID:27004466

  14. The apoptotic members CD95, BclxL, and Bcl-2 cooperate to promote cell migration by inducing Ca2+ flux from the endoplasmic reticulum to mitochondria

    Science.gov (United States)

    Fouqué, A; Lepvrier, E; Debure, L; Gouriou, Y; Malleter, M; Delcroix, V; Ovize, M; Ducret, T; Li, C; Hammadi, M; Vacher, P; Legembre, P

    2016-01-01

    Metalloprotease-processed CD95L (cl-CD95L) is a soluble cytokine that implements a PI3K/Ca2+ signaling pathway in triple-negative breast cancer (TNBC) cells. Accordingly, high levels of cl-CD95L in TNBC women correlate with poor prognosis, and administration of this ligand in an orthotopic xenograft mouse model accelerates the metastatic dissemination of TNBC cells. The molecular mechanism underlying CD95-mediated cell migration remains unknown. Here, we present genetic and pharmacologic evidence that the anti-apoptotic molecules BclxL and Bcl-2 and the pro-apoptotic factors BAD and BID cooperate to promote migration of TNBC cells stimulated with cl-CD95L. BclxL was distributed in both endoplasmic reticulum (ER) and mitochondrion membranes. The mitochondrion-localized isoform promoted cell migration by interacting with voltage-dependent anion channel 1 to orchestrate Ca2+ transfer from the ER to mitochondria in a BH3-dependent manner. Mitochondrial Ca2+ uniporter contributed to this flux, which favored ATP production and cell migration. In conclusion, this study reveals a novel molecular mechanism controlled by BclxL to promote cancer cell migration and supports the use of BH3 mimetics as therapeutic options not only to kill tumor cells but also to prevent metastatic dissemination in TNBCs. PMID:27367565

  15. GSK-3β inhibition by lithium confers resistance to chemotherapy-induced apoptosis through the repression of CD95 (Fas/APO-1) expression

    International Nuclear Information System (INIS)

    Lithium exerts neuroprotective actions that involve the inhibition of glycogen synthase kinase-3β (GSK-3β). Otherwise, recent studies suggest that sustained GSK-3β inhibition is a hallmark of tumorigenesis. In this context, the present study was undertaken to examine whether lithium modulated cancer cell sensitivity to apoptosis induced by chemotherapy agents. We observed that, in different human cancer cell lines, lithium significantly reduced etoposide- and camptothecin-induced apoptosis. In HepG2 cells, lithium repressed drug induction of CD95 expression and clustering at the cell surface as well as caspase-8 activation. Lithium acted through deregulation of GSK-3β signaling since (1) it provoked a rapid and sustained phosphorylation of GSK-3β on the inhibitory serine 9 residue; (2) the GSK-3β inhibitor SB-415286 mimicked lithium effects by repressing drug-induced apoptosis and CD95 membrane expression; and (3) lithium promoted the disruption of nuclear GSK-3β/p53 complexes. Moreover, the overexpression of an inactivated GSK-3β mutant counteracted the stimulatory effects of etoposide and camptothecin on a luciferase reporter plasmid driven by a p53-responsive sequence from the CD95 gene. In conclusion, we provide the first evidence that lithium confers resistance to apoptosis in cancer cells through GSK-3β inhibition and subsequent repression of CD95 gene expression. Our study also highlights the concerted action of GSK-3β and p53 on CD95 gene expression

  16. CD95 promotes metastatic spread via Sck in pancreatic ductal adenocarcinoma.

    Science.gov (United States)

    Teodorczyk, M; Kleber, S; Wollny, D; Sefrin, J P; Aykut, B; Mateos, A; Herhaus, P; Sancho-Martinez, I; Hill, O; Gieffers, C; Sykora, J; Weichert, W; Eisen, C; Trumpp, A; Sprick, M R; Bergmann, F; Welsch, T; Martin-Villalba, A

    2015-07-01

    Cancer stem cells (CSCs) have been implicated in the initiation and maintenance of tumour growth as well as metastasis. Recent reports link stemness to epithelial-mesenchymal transition (EMT) in cancer. However, there is still little knowledge about the molecular markers of those events. In silico analysis of RNA profiles of 36 pancreatic ductal adenocarcinomas (PDAC) reveals an association of the expression of CD95 with EMT and stemness that was validated in CSCs isolated from PDAC surgical specimens. CD95 expression was also higher in metastatic pancreatic cells than in primary PDAC. Pharmacological inhibition of CD95 activity reduced PDAC growth and metastasis in CSC-derived xenografts and in a murine syngeneic model. On the mechanistic level, Sck was identified as a novel molecule indispensable for CD95's induction of cell cycle progression. This study uncovers CD95 as a marker of EMT and stemness in PDAC. It also addresses the molecular mechanism by which CD95 drives tumour growth and opens tantalizing therapeutic possibilities in PDAC. PMID:25613377

  17. Ethylene signaling is required for the acceleration of cell death induced by the activation of At ME K5 in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Hongxia Liu; Ying Wang; Juan Xu; Tongbing Su; Guoqin Liu; Dongtao Ren

    2008-01-01

    Mitogen-activated protein kinases (MAPKs) are involved in the regulation of plant growth, development and responses to a wide variety of stimuli. In a conditional gain-of-function transgenic system, the activation of AtM£K5, a MAPK kinase, can in turn activate endogenous AtMAPK3 and AtMAPK6, and can lead to a striking increase in ethylene production and induce hypersensitive response (HR)-like cell death in Arabidopsis. However, the role of the increased ethylene production in regulating this HR-like cell death remains unknown. Using Arabidopsis transgenic plants that express AtMEK5DD , an active mutant of AtMEK5 that is under the control of a steroid-inducible promoter, we tested the contribution of ethylene to cell death. We found that ethylene biosynthesis occurs before cell death. Cell death was delayed by inhibiting AtMEK5-induced ethylene production using inhibitors of ACC-synthases, ACC-oxidases or ethylene receptors. In the mutants AtMEK5DDletrl-1 and AtMEK5DDlein2-l, both of which showed insen-sitivity to ethylene, the expression of AtMEKSDD protein, activity of AtMAPK3 and AtMAPK6, and ethylene production were the same as those seen in AtMEK.5 transgenic plants, but cell death was also delayed. These data suggest that ethylene signaling perception is required to accelerate cell death that is induced by AtMEK5 activation.

  18. Serum levels of soluble CD95 in patients with systemic lupus erythematosus

    Directory of Open Access Journals (Sweden)

    Magda I. M. El-Mahdy , Fatma A. Mourad* and Wafaa Afify M.H

    2001-06-01

    Full Text Available The present study was carried out on 30 patients with systemic lupus erythematosus (SLE and ten apparently healthy individuals as a control group.Systemic lupus erythematosus activity index (SLEDAI was applied to all patients. Anti-double stranded DNA antibodies (Anti-dsDNA Abs. , interleukin-18 (IL-18 and soluble CD95 (Apo-1/Fas were determined in the sera of all studied subjects. The mean ±SD SLEDAI in all patients was 15.25± 6.76 . The anti-dsDNA antibodies was positive in all studied patients (mean ± SD 264.36 ± 114.85 IU/ml. Serum IL-18 showed significant elevation in SLE patients as compared to the control group (Mean ±SD 246.13± 114.32I U/ml vs. 45.5 ± 7.32 IU/ml ; p < 0.001. Serum Soluble CD95 (sCD95showed significant increase in all SLE patients as compared to the control group (Mean±SD 648±116.96 pg/ml vs. 270±50.24 pg/ml ;p < 0.001. Serum sCD95 also showed significant rise in SLE patients with moderate activity as compared to those with mild activity (Mean ± SD 629.16± 72.54 pg/ml vs. 535 ±35.97 pg/ml; p<0.05. The serum level of sCD95 in SLE cases with severe activity showed significant increase when compared to those with moderate activity ( Mean±SD 797.5 ± 41.66 pg/ml vs. 629.16 ± 72.54 pg/ml ; p <0.001. Anti-dsDNA antibodies showed significant positive correlation with SLEDAI (r=0.772;p<0.01. IL-18 also showed a significant positive correlation with the SLEDAI (r=0.670 ;p<0.01. Soluble CD95 showed significant positive correlation with SLDAI (r=0.865 ; p<0.01, with anti-dsDNA antibodies (r=0.775 ;p<0.01 and with IL-18 (r =0.722 ; p<0.01. From these results it was concluded that serum sCD95 is increased in patients with systemic lupus erythematosus and it is correlated with anti-dsDNA antibodies , with IL-18 and with the disease activity, so it can be useful marker of disease activity for proper management and follow up of SLE patients.

  19. Upregulation of Fas-Fas-L (CD95/CD95L)-mediated epithelial apoptosis--a putative role in pouchitis?

    LENUS (Irish Health Repository)

    Coffey, J C

    2012-02-03

    INTRODUCTION: Ileal pouch-anal anastomosis (IPAA) remains the gold standard for patients with refractory ulcerative colitis. Pouchitis causes considerable morbidity in 40% of patients with IPAA. This study examined the role of increased epithelial apoptosis in the etiology of pouchitis. METHODS: Following ethical approval pouch biopsies taken from patients with a history of pouchitis were compared with age-matched controls from patients who were pouchitis free. Apoptosis was detected immunohistochemically using a monoclonal antibody (M30) and terminal deoxyribonucleotidyl transferase (TDT)-mediated dUTP-digoxigenin end labeling (TUNEL). Villous atrophy was assessed histologically and correlated with levels of apoptosis. Epithelial Fas-ligand (L) was also assessed immunohistochemically. RESULTS: A significant increase in TUNEL staining was seen at the epithelial but not at the lamina propria level for known pouchitis patients versus controls (0.091 vs 0.035; P < 0.01). Similarly, epithelial M30 immunoreactivity (0.225 vs 0.082; P < 0.05) and villous atrophy (0.035 vs 0.10; P < 0.05) were significantly increased in pouches with previous pouchitis when compared with normal pouches. Upregulation of Fas-L expression was characteristic of this epithelium. Mononuclear cells were strongly positive for Fas-L. Increased epithelial levels of apoptosis correlated with increased levels of villous atrophy. CONCLUSIONS: Our data suggest a role for elevated Fas-Fas-L (CD95-CD95L)-mediated epithelial apoptosis in the etiology of pouchitis. Increased levels of villous atrophy may result from increased apoptosis and thereby predispose to infection by otherwise apathogenic organisms.

  20. Sildenafil (Viagra) sensitizes prostate cancer cells to doxorubicin-mediated apoptosis through CD95.

    Science.gov (United States)

    Das, Anindita; Durrant, David; Mitchell, Clint; Dent, Paul; Batra, Surinder K; Kukreja, Rakesh C

    2016-01-26

    We previously reported that Sildenafil enhances apoptosis and antitumor efficacy of doxorubicin (DOX) while attenuating its cardiotoxic effect in prostate cancer. In the present study, we investigated the mechanism by which sildenafil sensitizes DOX in killing of prostate cancer (PCa) cells, DU145. The death receptor Fas (APO-1 or CD95) induces apoptosis in many carcinoma cells, which is negatively regulated by anti-apoptotic molecules such as FLIP (Fas-associated death domain (FADD) interleukin-1-converting enzyme (FLICE)-like inhibitory protein). Co-treatment of PCa cells with sildenafil and DOX for 48 hours showed reduced expression of both long and short forms of FLIP (FLIP-L and -S) as compared to individual drug treatment. Over-expression of FLIP-s with an adenoviral vector attentuated the enhanced cell-killing effect of DOX and sildenafil. Colony formation assays also confirmed that FLIP-S over-expression inhibited the DOX and sildenafil-induced synergistic killing effect as compared to the cells infected with an empty vector. Moreover, siRNA knock-down of CD95 abolished the effect of sildenafil in enhancing DOX lethality in cells, but had no effect on cell killing after treatment with a single agent. Sildenafil co-treatment with DOX inhibited DOX-induced NF-κB activity by reducing phosphorylation of IκB and nuclear translocation of the p65 subunit, in addition to down regulation of FAP-1 (Fas associated phosphatase-1, a known inhibitor of CD95-mediated apoptosis) expression. This data provides evidence that the CD95 is a key regulator of sildenafil and DOX mediated enhanced cell death in prostate cancer. PMID:26716643

  1. Sildenafil (Viagra) sensitizes prostate cancer cells to doxorubicin-mediated apoptosis through CD95

    OpenAIRE

    Das, Anindita; Durrant, David; Mitchell, Clint; Dent, Paul; Batra, Surinder K.; Kukreja, Rakesh C.

    2015-01-01

    We previously reported that Sildenafil enhances apoptosis and antitumor efficacy of doxorubicin (DOX) while attenuating its cardiotoxic effect in prostate cancer. In the present study, we investigated the mechanism by which sildenafil sensitizes DOX in killing of prostate cancer (PCa) cells, DU145. The death receptor Fas (APO-1 or CD95) induces apoptosis in many carcinoma cells, which is negatively regulated by anti-apoptotic molecules such as FLIP (Fas-associated death domain (FADD) interleu...

  2. CD95 maintains stem cell-like and non-classical EMT programs in primary human glioblastoma cells.

    Science.gov (United States)

    Drachsler, M; Kleber, S; Mateos, A; Volk, K; Mohr, N; Chen, S; Cirovic, B; Tüttenberg, J; Gieffers, C; Sykora, J; Wirtz, C R; Mueller, W; Synowitz, M; Martin-Villalba, A

    2016-01-01

    Glioblastoma (GBM) is one of the most aggressive types of cancer with limited therapeutic options and unfavorable prognosis. Stemness and non-classical epithelial-to-mesenchymal transition (ncEMT) features underlie the switch from normal to neoplastic states as well as resistance of tumor clones to current therapies. Therefore, identification of ligand/receptor systems maintaining this privileged state is needed to devise efficient cancer therapies. In this study, we show that the expression of CD95 associates with stemness and EMT features in GBM tumors and cells and serves as a prognostic biomarker. CD95 expression increases in tumors and with tumor relapse as compared with non-tumor tissue. Recruitment of the activating PI3K subunit, p85, to CD95 death domain is required for maintenance of EMT-related transcripts. A combination of the current GBM therapy, temozolomide, with a CD95 inhibitor dramatically abrogates tumor sphere formation. This study molecularly dissects the role of CD95 in GBM cells and contributes the rational for CD95 inhibition as a GBM therapy. PMID:27124583

  3. Pathogen-induced proapoptotic phenotype and high CD95 (Fas expression accompany a suboptimal CD8+ T-cell response: reversal by adenoviral vaccine.

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    José Ronnie Vasconcelos

    Full Text Available MHC class Ia-restricted CD8(+ T cells are important mediators of the adaptive immune response against infections caused by intracellular microorganisms. Whereas antigen-specific effector CD8(+ T cells can clear infection caused by intracellular pathogens, in some circumstances, the immune response is suboptimal and the microorganisms survive, causing host death or chronic infection. Here, we explored the cellular and molecular mechanisms that could explain why CD8(+ T cell-mediated immunity during infection with the human protozoan parasite Trypanosoma cruzi is not optimal. For that purpose, we compared the CD8(+ T-cell mediated immune responses in mice infected with T. cruzi or vaccinated with a recombinant adenovirus expressing an immunodominant parasite antigen. Several functional and phenotypic characteristics of specific CD8(+ T cells overlapped. Among few exceptions was an accelerated expansion of the immune response in adenoviral vaccinated mice when compared to infected ones. Also, there was an upregulated expression of the apoptotic-signaling receptor CD95 on the surface of specific T cells from infected mice, which was not observed in the case of adenoviral-vaccinated mice. Most importantly, adenoviral vaccine provided at the time of infection significantly reduced the upregulation of CD95 expression and the proapoptotic phenotype of pathogen-specific CD8(+ cells expanded during infection. In parallel, infected adenovirus-vaccinated mice had a stronger CD8 T-cell mediated immune response and survived an otherwise lethal infection. We concluded that a suboptimal CD8(+ T-cell response is associated with an upregulation of CD95 expression and a proapoptotic phenotype. Both can be blocked by adenoviral vaccination.

  4. Expression of Fas (CD95/APO-1) ligand by human breast cancers: significance for tumor immune privilege.

    LENUS (Irish Health Repository)

    O'Connell, J

    2012-02-03

    Breast cancers have been shown to elicit tumor-specific immune responses. As in other types of cancer, the antitumor immune response fails to contain breast tumor growth, and a reduction in both the quantity and cytotoxic effectiveness of tumor-infiltrating lymphocytes (TILs) is associated with a poorer prognosis. Fas ligand (FasL) induces apoptotic death of activated lymphocytes that express its cell surface receptor, FasR (CD95\\/APO-1). FasL-mediated apoptosis of activated lymphocytes contributes to normal immune downregulation through its roles in tolerance acquisition, immune response termination, and maintenance of immune privilege in the eye, testis, and fetus. In this report, we demonstrate that breast carcinomas express FasL. Using in situ hybridization and immunohistochemistry, we show that breast tumors constitutively express FasL at both the mRNA and protein levels, respectively. FasL expression is prevalent in breast cancer: 100% of breast tumors (17 of 17) were found to express FasL, and expression occurred over more than 50% of the tumor area in all cases. By immunohistochemistry, FasR was found to be coexpressed with FasL throughout large areas of all the breast tumors. This suggests that the tumor cells had acquired intracellular defects in FasL-mediated apoptotic signaling. FasL and FasR expression were independent of tumor type or infiltrative capacity. FasL expressed by tumor cells has previously been shown to kill Fas-sensitive lymphoid cells in vitro and has been associated with apoptosis of TILs in vivo. We conclude that mammary carcinomas express FasL in vivo as a potential inhibitor of the antitumor immune response.

  5. Expression of Fas (CD95/APO-1) Ligand by Human Breast Cancers: Significance for Tumor Immune Privilege

    OpenAIRE

    O’Connell, Joe; Bennett, Michael W; O’Sullivan, Gerald C.; O’Callaghan, Jim; Collins, J. Kevin; Shanahan, Fergus

    1999-01-01

    Breast cancers have been shown to elicit tumor-specific immune responses. As in other types of cancer, the antitumor immune response fails to contain breast tumor growth, and a reduction in both the quantity and cytotoxic effectiveness of tumor-infiltrating lymphocytes (TILs) is associated with a poorer prognosis. Fas ligand (FasL) induces apoptotic death of activated lymphocytes that express its cell surface receptor, FasR (CD95/APO-1). FasL-mediated apoptosis of acti...

  6. Assessment of Apoptosis Level of Naive CD8+ T-lymphocytes in Children with Acute Infectious Mononucleosis in CD95 and DR3 Receptors Activation

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    Е.N. Filatova

    2015-09-01

    Full Text Available The aim of the investigation was to estimate the relation of CD95 and DR3 receptors activation with apoptosis level of naive cytotoxic Т-lymphocytes (nCТL in children with acute infectious mononucleosis (AIM. Materials and Methods. The test materials were peripheral blood samples of healthy children and children with AIM. nCTL were isolated by negative immunomagnetic separation. Specific activation of CD95 and DR3 receptors was performed using monoclonal antibodies. An apoptosis level and expression of receptors were studied by flow cytometry. Results. The percentage of cell apoptosis decreased in children with AIM in freshly isolated nCTL, as well as in CD95 receptor activation compared to healthy children. nCTL apoptosis in healthy children regardless of culture conditions was accompanied by the reduced quantity of CD95+DR3– cells and CD95 expression density on their surface. In children with AIM the decrease of these indices required CD95 activation. Compared to healthy children, the percentage of CD95+DR3+ cells in children with AIM decreased in CD95 activation. In CD95 receptor activation in healthy children and children with AIM, the content of CD95+DR3+ cells correlated directly with an apoptosis level. DR3 receptor activation was accompanied neither by nCTL apoptosis level change nor the changed content of DR3+ cells in both healthy children and children with AIM. Conclusion. nCTL are less sensitive to apoptosis in children with AIM compared to healthy children. DR3 receptor activation results in no change of nCTL apoptosis level both in healthy children and children with AIM. CD95 activation in patients with AIM is accompanied by increased resistance of CD95+DR3– cells to apoptosis and the susceptibility to apoptosis of CD95+DR3+ cells. The evaluation of nCTL susceptibility to CD95-induced apoptosis in AIM can serve as a subtest to assess the state of a cell component of immune system.

  7. Prognostic significance of CD95, P53, and BCL2 expression in extranodal non-Hodgkin's lymphoma

    OpenAIRE

    Chatzitolios, Anastasios; Venizelos, Ioannis; Tripsiannis, Gregory; Anastassopoulos, George; Papadopoulos, Nikolaos

    2010-01-01

    Abstract Apoptosis-related proteins play an important role in lymphoma cell death during chemotherapy. In our study, we investigated the prognostic significance of CD95, BCL2, and P53 expression in extranodal non-Hodgkin?s lymphoma (NHL). We examined 71 patients with extranodal NHL [45 diffuse large B-cell lymphomas (DLBCLs) and 26 mucosa-associated lymphoid tissue lymphomas (MALTLs)], 35 male and 36 female, with a median age of 65.8 years. The most common site of origin was the st...

  8. Apoptosis induction in Jurkat cells and sCD95 levels in women's sera are related with the risk of developing cervical cancer

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    Bravo-Cuellar Alejandro

    2008-04-01

    Full Text Available Abstract Background Currently, there is clear evidence that apoptosis plays an important role in the development and progression of tumors. One of the best characterized apoptosis triggering systems is the CD95/Fas/APO-1 pathway; previous reports have demonstrated high levels of soluble CD95 (sCD95 in serum of patients with some types of cancer. Cervical cancer is the second most common cancer among women worldwide. As a first step in an attempt to design a minimally invasive test to predict the risk of developing cervical cancer in patients with precancerous lesions, we used a simple assay based on the capacity of human serum to induce apoptosis in Jurkat cells. We evaluated the relationship between sCD95 levels and the ability to induce apoptosis in Jurkat cells in cervical cancer patients and controls. Methods Jurkat cells were exposed to serum from 63 women (20 healthy volunteers, 21 with cervical intraepithelial neoplasia grade I [CIN 1] and 22 with cervical-uterine carcinoma. The apoptotic rate was measured by flow cytometry using Annexin-V-Fluos and Propidium Iodide as markers. Serum levels of sCD95 and soluble CD95 ligand (sCD95L were measured by ELISA kits. Results We found that serum from almost all healthy women induced apoptosis in Jurkat cells, while only fifty percent of the sera from women with CIN 1 induced cell death in Jurkat cells. Interestingly, only one serum sample from a patient with cervical-uterine cancer was able to induce apoptosis, the rest of the sera protected Jurkat cells from this killing. We were able to demonstrate that elimination of Jurkat cells was mediated by the CD95/Fas/Apo-1 apoptotic pathway. Furthermore, the serum levels of sCD95 measured by ELISA were significantly higher in women with cervical cancer. Conclusion Our results demonstrate that there is a strong correlation between low levels of sCD95 in serum of normal women and higher apoptosis induction in Jurkat cells. We suggest that an analysis of

  9. Killing of naive T cells by CD95L-transfected dendritic cells (DC): in vivo study using killer DC-DC hybrids and CD4(+) T cells from DO11.10 mice.

    Science.gov (United States)

    Kusuhara, Masahiro; Matsue, Keiko; Edelbaum, Dale; Loftus, Julie; Takashima, Akira; Matsue, Hiroyuki

    2002-04-01

    Dendritic cells (DC) play the dual task of initiating cellular immunity against potentially harmful foreign antigens (Ag), while maintaining immunological tolerance to self-Ag and environmental Ag. As an approach to induce Ag-specific suppression, we and others introduced CD95 ligand (L) cDNA into DC. The resulting "killer" DC delivered apoptotic signals, instead of activation signals, to primed CD4(+) T cells in vitro and induced Ag-specific immunosuppression in vivo. To study the impact of killer DC on naive T cells, the fate of Ag-reactive T cells and the extent of their depletion after killer DC treatment, we performed in vitro and in vivo reconstitution experiments using: (a) killer DC-DC hybrids created between CD95L-transduced XS106 DC clone (A/J origin) and splenic DC from BALB/c mice, (b) CD4(+) T cells isolated from DO11.10 transgenic mice (BALB/c background), and (c) OVA(323-339) peptide as relevant Ag. Ovalbumin (OVA)-pulsed killer DC-DC hybrids inhibited DO11.10 T cell activation triggered by conventional DC, instead of inducing their activation. Rapid apoptosis of T cells was observed after co-culture with OVA-pulsed killer DC-DC hybrids, but not with non-pulsed killer DC-DC hybrids or OVA-pulsed control DC-DC hybrids. For in vivo reconstitution, (BALB/cxA/J)F1 mice received subcutaneous administration of killer DC-DC hybrids, followed by intravenous inoculation of DO11.10 T cells. Killer DC-DC hybrids migrated preferentially to draining lymph nodes albeit with relatively low efficiency (0.5-1% recovery) and they induced significant, but incomplete (30-40%) killing of DO11.10 T cells in this location. These results document the abilities of CD95L-transduced DC to trigger apoptosis of naive T cells in an Ag-specific manner, to overrule T cell activation signals delivered by conventional DC, and to reduce local frequencies of Ag-reactive T cells in vivo. Our data also uncover two major limitations (relatively low homing efficiency and incomplete

  10. ANTI-APOPTOTIC EFFECT OF CD95 RECEPTOR IN NA VE CD8+ T-LYMPHOCYTES IN CHILDREN WITH ACUTE INFECTIOUS MONONUCLEOSIS

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    E. N. Filatova

    2016-01-01

    Full Text Available Acute infectious mononucleosis is a widespread viral disease, which most often manifests in childhood. The development of acute infectious mononucleosis is accompanied by the change of the CD4+/CD8+ T-lymphocytes ratio and the increase of the virus-specific CD8+ cytotoxic T-lymphocytes number. One of the T-lymphocytes number regulation mechanisms is the modulation of their progenitor cells apoptosis. The death receptor CD95 takes part in the regulation of T-lymphocytes apoptosis, including naïve T-cells. We studied the effect of CD95 receptor activation on apoptosis of naïve CD4+ and naïve cytotoxic CD8+ T-lymphocytes in healthy children and children with acute infectious mononucleosis. In this study children with acute infectious mononucleosis at the age of 9 to 16 years were included. For comparison healthy children of the same age with no clinical and laboratory signs of the disease were used. Naïve CD4+ and naïve cytotoxic CD8+ T-lymphocytes were isolated by negative magnetic immunoseparation. The analysis of naïve T-cells apoptosis and the CD95 receptor surface expression density was performed by using the flow cytometry analysis. The analysis of T-cells was performed in three variants: freshly isolated naïve CD4+ T-lymphocytes and naïve cytotoxic CD8+ T-lymphocytes, and also cells after 24 hours of the cultivation with anti-CD95 monoclonal antibodies or without them. In healthy children both CD95– and CD95+ naïve CD4+ T-lymphocytes underwent apoptosis. In children with acute infectious mononucleosis CD95– naïve CD4+ T-lymphocytes lost their susceptibility to apoptosis induction. In healthy children and children with acute infectious mononucleosis CD95– naïve cytotoxic CD8+ T-lymphocytes were resistant to apoptosis in contrast to CD95+ naïve CD4+ T-lymphocytes. In healthy children CD95 receptor did not induce apoptosis of isolated naïve CD4+ T-lymphocytes and naïve cytotoxic CD8+ T-lymphocytes. In children with acute

  11. CD95/Fas-induced ceramide formation proceeds with slow kinetics and is not blocked by caspase-3/CPP32 inhibition.

    Science.gov (United States)

    Tepper, A D; Cock, J G; de Vries, E; Borst, J; van Blitterswijk, W J

    1997-09-26

    The current confusion regarding the relevance of endogenous ceramide in mediating CD95/Fas-induced apoptosis is based mainly on (i) discrepancies in kinetics of the ceramide response between different studies using the same apoptotic stimulus and (ii) the observation that late ceramide formation (hours) often parallels apoptosis onset. We investigated CD95-induced ceramide formation in Jurkat cells, using two methods (radiolabeling/thin layer chromatography and benzoylation/high performance liquid chromatography), which, unlike the commonly used diglyceride kinase assay, discriminate between ceramide species and de novo formed dihydroceramide. We demonstrate that ceramide accumulates after several hours, reaching a 7-fold increase after 8 h, kinetics closely paralleling apoptosis induction. No fast response was observed, not even in the presence of inhibitors of ceramide metabolism. The majority ( approximately 70%) of the ceramide response remained unaffected when apoptosis was completely inhibited at the level of caspase-3/CPP32 processing by the inhibitor peptide DEVD-CHO. Exogenous cell-permeable C2-ceramide induced the proteolytic processing of caspase-3, albeit with somewhat slower kinetics than with CD95. DEVD-CHO dose-dependently inhibited C2-ceramide- or exogenous sphingomyelinase-induced apoptosis. The results support the idea that ceramide acts in conjunction with the caspase cascade in CD95-induced apoptosis. PMID:9305886

  12. Endoplasmic reticulum-resident E3 ubiquitin ligase Hrd1 controls B-cell immunity through degradation of the death receptor CD95/Fas

    Science.gov (United States)

    Kong, Sinyi; Yang, Yi; Xu, Yuanming; Wang, Yajun; Zhang, Yusi; Melo-Cardenas, Johanna; Xu, Xiangping; Gao, Beixue; Thorp, Edward B.; Zhang, Donna D.; Zhang, Bin; Song, Jianxun; Zhang, Kezhong; Zhang, Jianning; Zhang, Jinping; Li, Huabin; Fang, Deyu

    2016-01-01

    Humoral immunity involves multiple checkpoints during B-cell development, maturation, and activation. The cell death receptor CD95/Fas-mediated apoptosis plays a critical role in eliminating the unwanted activation of B cells by self-reactive antigens and in maintaining B-cell homeostasis through activation-induced B-cell death (AICD). The molecular mechanisms controlling AICD remain largely undefined. Herein, we show that the E3 ubiquitin ligase Hrd1 protected B cells from activation-induced cell death by degrading the death receptor Fas. Hrd1-null B cells exhibited high Fas expression during activation and rapidly underwent Fas-mediated apoptosis, which could be largely inhibited by FasL neutralization. Fas mutation in Hrd1 KO mice abrogated the increase in B-cell AICD. We identified Hrd1 as the first E3 ubiquitin ligase of the death receptor Fas and Hrd1-mediated Fas destruction as a molecular mechanism in regulating B-cell immunity. PMID:27573825

  13. Transfer of Fas (CD95 protein from the cell surface to the surface of polystyrene beads coated with anti-Fas antibody clone CH-11

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    H. Sawai

    2010-02-01

    Full Text Available Mouse monoclonal anti-Fas (CD95 antibody clone CH-11 has been widely used in research on apoptosis. CH-11 has the ability to bind to Fas protein on cell surface and induce apoptosis. Here, we used polystyrene beads coated with CH-11 to investigate the role of lipid rafts in Fas-mediated apoptosis in SKW6.4 cells. Unexpectedly, by treatment of the cells with CH-11-coated beads Fas protein was detached from cell surface and transferred to the surface of CH-11-coated beads. Western blot analysis showed that Fas protein containing both extracellular and intracellular domains was attached to the beads. Fas protein was not transferred from the cells to the surface of the beads coated with other anti-Fas antibodies or Fas ligand. Similar phenomenon was observed in Jurkat T cells. Furthermore, CH-11-induced apoptosis was suppressed by pretreatment with CH-11-coated beads in Jurkat cells. These results suggest that CH-11 might possess distinct properties on Fas protein compared with other anti-Fas antibodies or Fas ligand, and also suggest that caution should be needed to use polystyrene beads coated with antibodies such as CH-11.

  14. Synthetic Bichalcone TSWU-BR23 Induces Apoptosis of Human Colon Cancer HT-29 Cells by p53-Mediated Mitochondrial Oligomerization of BAX/BAK and Lipid Raft Localization of CD95/FADD.

    Science.gov (United States)

    Lin, Meng-Liang; Chen, Shih-Shun; Wu, Tian-Shung

    2015-10-01

    A synthetic bichalcone analog, (E)-1-(3-((4-(4-acetylphenyl)piperazin-1-yl)methyl)-4-hydroxy-5-methoxyphenyl)-3-(pyridin-3-yl)prop-2-en-1-one (TSWU-BR23), has been shown to induce apoptosis in human colon cancer HT-29 cells involving the induction of CD95 and FAS-associated protein death domain (FADD), but its precise mechanism of action has not been fully elucidated. Using cell-surface biotinylation and sucrose density-gradient-based membrane flotation techniques, we showed that the disruption of TSWU-BR23-induced lipid raft localization of CD95/FADD by cholesterol-depleting agent (methyl-β-cyclodextrin) was reversed by cholesterol replenishment. Blockade of p53 expression by short-hairpin RNA (shRNA) suppressed oligomeric Bcl-2-associated x protein (BAX)/Bcl-2 antagonist killer 1 (BAK)-mediated mitochondrial apoptosis but did not inhibit lipid raft localization of CD95/FADD and pro-caspase-8 cleavage induced by TSWU-BR23. Co-expression of p53 shRNA and dominant-negative mutant of FADD completely inhibited TSWU-BR32-induced mitochondrial apoptotic cell death. Collectively, these data demonstrate that TSWU-BR23 leads to HT-29 cell apoptosis by inducing p53-mediated mitochondrial oligomerization of BAX/BAK and the localization of CD95/FADD with lipid rafts at the cell surface.

  15. Different Types of Cell Death Induced by Enterotoxins

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    Ming-Yuan Hong

    2010-08-01

    Full Text Available The infection of bacterial organisms generally causes cell death to facilitate microbial invasion and immune escape, both of which are involved in the pathogenesis of infectious diseases. In addition to the intercellular infectious processes, pathogen-produced/secreted enterotoxins (mostly exotoxins are the major weapons that kill host cells and cause diseases by inducing different types of cell death, particularly apoptosis and necrosis. Blocking these enterotoxins with synthetic drugs and vaccines is important for treating patients with infectious diseases. Studies of enterotoxin-induced apoptotic and necrotic mechanisms have helped us to create efficient strategies to use against these well-characterized cytopathic toxins. In this article, we review the induction of the different types of cell death from various bacterial enterotoxins, such as staphylococcal enterotoxin B, staphylococcal alpha-toxin, Panton-Valentine leukocidin, alpha-hemolysin of Escherichia coli, Shiga toxins, cytotoxic necrotizing factor 1, heat-labile enterotoxins, and the cholera toxin, Vibrio cholerae. In addition, necrosis caused by pore-forming toxins, apoptotic signaling through cross-talk pathways involving mitochondrial damage, endoplasmic reticulum stress, and lysosomal injury is discussed.

  16. Interleukin-3 prevents neuronal death induced by amyloid peptide

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    Otth Carola

    2007-10-01

    Full Text Available Abstract Background Interleukin-3 (IL-3 is an important glycoprotein involved in regulating biological responses such as cell proliferation, survival and differentiation. Its effects are mediated via interaction with cell surface receptors. Several studies have demonstrated the expression of IL-3 in neurons and astrocytes of the hippocampus and cortices in normal mouse brain, suggesting a physiological role of IL-3 in the central nervous system. Although there is evidence indicating that IL-3 is expressed in some neuronal populations, its physiological role in these cells is poorly known. Results In this study, we demonstrated the expression of IL-3 receptor in cortical neurons, and analyzed its influence on amyloid β (Aβ-treated cells. In these cells, IL-3 can activate at least three classical signalling pathways, Jak/STAT, Ras/MAP kinase and the PI 3-kinase. Viability assays indicated that IL-3 might play a neuroprotective role in cells treated with Aβ fibrils. It is of interest to note that our results suggest that cell survival induced by IL-3 required PI 3-kinase and Jak/STAT pathway activation, but not MAP kinase. In addition, IL-3 induced an increase of the anti-apoptotic protein Bcl-2. Conclusion Altogether these data strongly suggest that IL-3 neuroprotects neuronal cells against neurodegenerative agents like Aβ.

  17. Increase of p25 associated with cortical neuronal death induced by hypoxia.

    Science.gov (United States)

    Huang, Tianwen; Fang, Lijun; Lin, Zhiying; Huang, En; Ye, Qinyong

    2016-09-01

    The mechanisms of neuronal damage in hypoxic cerebral cortex are complicated. Recent studies indicated that deregulation of Cdk5 was involved in neuronal death induced by hypoxia (1% O2). However, the pathological effect of Cdk5 is not fully elucidated. Therefore, in order to decipher the effect of Cdk5 on cellular death in hypoxic condition, the Cdk5 and its activator p35/p25 were investigated in cortical neurons at 10 DIV (Days In Vitro). Upon exposure to hypoxia, the cortical neurons showed a time-dependent increase of neuronal death compared to normoxia-treated control neurons. In correlation to the increase of neuronal death under hypoxia, the level of p25, a truncated form of p35, also increased in a time-dependent manner. Importantly, inhibition of Cdk5 kinase activity by roscovitine protected neurons from death under hypoxic stress. In contrast, ectopic upregulation of Cdk5 kinase activity in neurons expressing p25 led to an increase of neuronal death in comparison to control neurons expressing GFP. It suggests that ectopic increase of Cdk5 kinase activity through conversion of p35 to p25 is involved in the process of neuronal death induced by hypoxia. PMID:27402274

  18. Prototypical antipsychotic drugs protect hippocampal neuronal cultures against cell death induced by growth medium deprivation

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    Williams Sylvain

    2006-03-01

    Full Text Available Abstract Background Several clinical studies suggested that antipsychotic-based medications could ameliorate cognitive functions impaired in certain schizophrenic patients. Accordingly, we investigated the effects of various dopaminergic receptor antagonists – including atypical antipsychotics that are prescribed for the treatment of schizophrenia – in a model of toxicity using cultured hippocampal neurons, the hippocampus being a region of particular relevance to cognition. Results Hippocampal cell death induced by deprivation of growth medium constituents was strongly blocked by drugs including antipsychotics (10-10-10-6 M that display nM affinities for D2 and/or D4 receptors (clozapine, haloperidol, (±-sulpiride, domperidone, clozapine, risperidone, chlorpromazine, (+-butaclamol and L-741,742. These effects were shared by some caspases inhibitors and were not accompanied by inhibition of reactive oxygen species. In contrast, (--raclopride and remoxipride, two drugs that preferentially bind D2 over D4 receptors were ineffective, as well as the selective D3 receptor antagonist U 99194. Interestingly, (--raclopride (10-6 M was able to block the neuroprotective effect of the atypical antipsychotic clozapine (10-6 M. Conclusion Taken together, these data suggest that D2-like receptors, particularly the D4 subtype, mediate the neuroprotective effects of antipsychotic drugs possibly through a ROS-independent, caspase-dependent mechanism.

  19. The expression of Death Inducer-Obliterator (DIDO) variants in Myeloproliferative Neoplasms.

    Science.gov (United States)

    Berzoti-Coelho, Maria Gabriela; Ferreira, Aline Fernanda; de Souza Nunes, Natalia; Pinto, Mariana Tomazini; Júnior, Maurício Cristiano Rocha; Simões, Belinda Pinto; Martínez-A, Carlos; Souto, Elizabeth Xisto; Panepucci, Rodrigo Alexandre; Covas, Dimas Tadeu; Kashima, Simone; Castro, Fabíola Attié

    2016-07-01

    Chronic Myeloid Leukemia (CML), Polycythemia Vera (PV), Essential Thrombocythemia (ET) and Primary Myelofibrosis (PMF) are Myeloproliferative Neoplasms (MPN) characterized by clonal myeloproliferation without cell maturation impairment. CML pathogenesis is associated with the Ph chromosome leading to BCR-ABL tyrosine-kinase constitutive expression. The Ph negative MPN (PV, ET and PMF) are characterized by the mutation JAK2(V617F) of the JAK2 protein in the auto-inhibitory JH2 domain, which is found in most PV patients and in approximately half of ET and PMF patients. Considerable effort is being made to understand the role of JAK2(V617F) at the MPN initiation and to clarify the pathogenesis and apoptosis resistance in CML, PV, ET and PMF patients. In the present investigation, we evaluated the Death Inducer-Obliterator (DIDO) (variants DIDO 1, 2 and 3) levels in CML, PV, ET and PMF patients. Our data reported the DIDO 1, 2 and 3 differential expressions in Myeloproliferative Neoplasms. PMID:27282563

  20. Metallomics insights into the programmed cell death induced by metal-based anticancer compounds.

    Science.gov (United States)

    Tan, Cai-Ping; Lu, Yi-Ying; Ji, Liang-Nian; Mao, Zong-Wan

    2014-05-01

    Since the discovery of cisplatin more than 40 years ago, enormous research efforts have been dedicated to developing metal-based anticancer agents and to elucidating the mechanisms involved in the action of these compounds. Abnormal metabolism and the evasion of apoptosis are important hallmarks of malignant transformation, and the induction of apoptotic cell death has been considered to be a main pathway by which cytotoxic metal complexes combat cancer. However, many cancers have cellular defects involving the apoptotic machinery, which results in an acquired resistance to apoptotic cell death and therefore reduced chemotherapeutic effectiveness. Over the past decade, it has been revealed that a growing number of cell death pathways induced by metal complexes are not dependent on apoptosis. Metal complexes specifically triggering these alternative cell death pathways have been identified and explored as novel cancer treatment options. In this review, we discuss recent examples of metallomics studies on the different types of cell death induced by metal-based anticancer drugs, especially on the three major forms of programmed cell death (PCD) in mammalian cells: apoptosis, autophagy and regulated necrosis, also called necroptosis.

  1. T-cell factor (TCF/LEF1) binding elements (TBEs) of FasL (Fas ligand or CD95 ligand) bind and cluster Fas (CD95) and form complexes with the TCF-4 and b-catenin transcription factors in vitro and in vivo which result in triggering cell death and/or cell activation.

    Science.gov (United States)

    Liu, Xia; Huang, Yuwei; Zhang, Yuanyuan; Li, Xiaohong; Liu, Chun; Huang, Shen; Xu, Dezhi; Wu, Yang; Liu, Xiaojuan

    2016-08-01

    T-cell factor 4 (TCF4) is an important transcription factor of the Wnt signaling system. β-catenin, an upstream protein of TCF4, accumulates in the cytoplasm, then translocates to the nucleus to activate the β-catenin/T-cell factor/lymphoid enhancer factor (TCF/LEF) transcriptional machinery and regulates target genes. Previous studies showed that TCF4 was involved in cell proliferation and apoptosis. However, its expression and function in central nervous system injury are unclear. We performed a traumatic brain injury (TBI) model in adult rats. The expression of TCF4 in the brain cortex detected by Western blot increased after TBI. Double immunofluorescence staining revealed that TCF4 was expressed by neurons and microglia. In addition, co-localization of TCF4 with active caspase-3 or proliferating cell nuclear antigen was observed in neurons and microglia, respectively, suggesting that TCF4 might participate in neuronal apoptosis and microglial proliferation after TBI. To further investigate the functions of TCF4, PC12 and HAPI cells were employed to establish a neuronal apoptosis and microglial proliferation model in vitro, respectively. Knocking down TCF4 with siRNA proved the pro-apoptotic and pro-proliferation effect of TCF4 in PC12 and HAPI cells, respectively. Taken together, TCF4 might promote neuronal apoptosis and microglial proliferation after TBI. PMID:27090258

  2. Cell death induced by mechanical compression on engineered muscle results from a gradual physiological mechanism.

    Science.gov (United States)

    Wu, Yabin; van der Schaft, Daisy W J; Baaijens, Frank P; Oomens, Cees W J

    2016-05-01

    Deep tissue injury (DTI), a type of pressure ulcer, arises in the muscle layers adjacent to bony prominences due to sustained mechanical loading. DTI presents a serious problem in the clinic, as it is often not visible until reaching an advanced stage. One of the causes can be direct mechanical deformation of the muscle tissue and cell. The mechanism of cell death induced by mechanical compression was studied using bio-artificial skeletal muscle tissues. Compression was applied by placing weights on top of the constructs. The morphological changes of the cytoskeleton and the phosphorylation of mitogen-activated protein kinases (MAPK) under compression were investigated. Moreover, inhibitors for each of the three major MAPK groups, p38, ERK, and JNK, were applied separately to look at their roles in the compression caused apoptosis and necrosis. The present study for the first time showed that direct mechanical compression activates MAPK phosphorylation. Compression also leads to a gradual destruction of the cytoskeleton. The percentage apoptosis is strongly reduced by p38 and JNK inhibitors down to the level of the unloaded group. This phenomenon could be observed up to 24h after initiation of compression. Therefore, cell death in bio-artificial muscle tissue caused by mechanical compression is primarily caused by a physiological mechanism, rather than through a physical mechanism which kills the cell directly. These findings reveal insight of muscle cell death under mechanical compression. Moreover, the result indicates a potential clinical solution to prevent DTI by pre-treating with p38 or/and JNK inhibitors. PMID:26961799

  3. Protective effect of aqueous extract from Spirulina platensis against cell death induced by free radicals

    Directory of Open Access Journals (Sweden)

    Radhakrishnan Ammu

    2010-09-01

    Full Text Available Abstract Background Spirulina is a commercial alga well known to contain various antioxidants, especially phycocyanin. Apart from being sold as a nutraceutical, Spirulina is incorporated as a functional ingredient in food products and beverages. Most of the previous reports on antioxidant activity of Spirulina were based on chemical rather than cell-based assays. The primary objective of this study was to assess the antioxidant activity of aqueous extract from Spirulina based on its protective effect against cell death induced by free radicals. Methods The antioxidant activity of the cold water extract from food-grade Spirulina platensis was assessed using both chemical and cell-based assays. In the cell-based assay, mouse fibroblast cells (3T3 cells were incubated for 1 h in medium containing aqueous extract of Spirulina or vitamin C (positive control at 25, 125 and 250 μg/mL before the addition of 50 μM 1,1-diphenyl-2-picrylhydrazyl (DPPH or 3-ethylbenzothiazoline-6-sulfonic acid (ABTS. The cells were incubated for another 24 h before being assessed for cell death due to apoptosis using the Cell Death Detection ELISA Kit. Spectrophotometric assays based on DPPH and ABTS were also used to assess the antioxidant activity of the extract compared to vitamin C and vitamin E (positive controls. Results Spirulina extract did not cause cytotoxic effect on 3T3 cells within the range of concentrations tested (0 - 250 μg/mL. The extract reduced significantly (p Conclusions The results showed that aqueous extract of Spirulina has a protective effect against apoptotic cell death due to free radicals. The potential application of incorporating Spirulina into food products and beverages to enhance their antioxidant capacity is worth exploring.

  4. HIV-1 trans-activator of transcription substitutes for oxidative signaling in activation-induced T cell death.

    Science.gov (United States)

    Gülow, Karsten; Kaminski, Marcin; Darvas, Katalin; Süss, Dorothee; Li-Weber, Min; Krammer, Peter H

    2005-05-01

    Termination of an immune response requires elimination of activated T lymphocytes by activation-induced cell death (AICD). In AICD, CD95 (Apo-1/Fas) ligand (L) triggers apoptosis of CD95-positive activated T lymphocytes. In AIDS patients, AICD is strongly enhanced and accelerated. We and others have previously shown that HIV-1 trans-activator of transcription (HIV-1 Tat) sensitizes T cells toward CD95-mediated apoptosis and up-regulates CD95L expression by affecting the cellular redox balance. In this study, we show that it is hydrogen peroxide (H(2)O(2)) that functions as an essential second messenger in TCR signaling. The H(2)O(2) signal combined with simultaneous calcium (Ca(2+)) influx into the cytosol constitutes the minimal requirement for induction of CD95L expression. Either signal alone is insufficient. We further show that HIV-1 Tat interferes with TCR signaling and induces a H(2)O(2) signal. H(2)O(2) generated by HIV-1 Tat combines with CD4-dependent calcium influx and causes massive T cell apoptosis. Thus, our data provide an explanation for CD4(+) T lymphocyte depletion during progression of AIDS.

  5. Evaluation of the contribution of multiple DAMPs and DAMP receptors in cell death-induced sterile inflammatory responses.

    Directory of Open Access Journals (Sweden)

    Hiroshi Kataoka

    Full Text Available When cells die by necrosis in vivo they stimulate an inflammatory response. It is thought that this response is triggered when the injured cells expose proinflammatory molecules, collectively referred to as damage associated molecular patterns (DAMPs, which are recognized by cells or soluble molecules of the innate or adaptive immune system. Several putative DAMPs and/or their receptors have been identified, but whether and how much they participate in responses in vivo is incompletely understood, and they have not previously been compared side-by-side in the same models. This study focuses on evaluating the contribution of multiple mechanisms that have been proposed to or potentially could participate in cell death-induced inflammation: The third component of complement (C3, ATP (and its receptor P2X7, antibodies, the C-type lectin receptor Mincle (Clec4e, and protease-activated receptor 2 (PAR2. We investigate the role of these factors in cell death-induced inflammation to dead cells in the peritoneum and acetaminophen-induced liver damage. We find that mice deficient in antibody, C3 or PAR2 have impaired inflammatory responses to dying cells. In contrast there was no reduction in inflammation to cell death in the peritoneum or liver of mice that genetically lack Mincle, the P2X7 receptor or that were treated with apyrase to deplete ATP. These results indicate that antibody, complement and PAR2 contribute to cell death-induced inflammation but that Mincle and ATP- P2X7 receptor are not required for this response in at least 2 different in vivo models.

  6. The differential DRP1 phosphorylation and mitochondrial dynamics in the regional specific astroglial death induced by status epilepticus

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    Ah-Reum eKo

    2016-05-01

    Full Text Available The response and susceptibility to astroglial degenerations are relevant to the distinctive properties of astrocytes in a hemodynamic-independent manner following status epilepticus (SE.Since impaired mitochondrial fission plays an important role in mitosis, apoptosis and programmed necrosis, we investigated whether the unique pattern of mitochondrial dynamics is involved in the characteristics of astroglial death induced by SE. In the present study, SE induced astroglial apoptosis in the molecular layer of the dentate gyrus, accompanied by decreased mitochondrial length. In contrast, clasmatodendritic (autophagic astrocytes in the CA1 region showed mitochondrial elongation induced by SE. Mdivi-1 (an inhibitor of mitochondrial fission effectively attenuated astroglial apoptosis, but WY14643 (an enhancer of mitochondrial fissionaggravated it. In addition, Mdivi-1accelerated clasmatodendritic changes in astrocytes. These regional specific mitochondrial dynamics in astrocytes were closely correlated with dynamin-related protein (DRP1, a mitochondrial fission protein phosphorylation, not optic atrophy 1 (a mitochondrial fusion protein expression. To the best of our knowledge, the present data demonstrate for the first time the novel role of DRP1-mediated mitochondrial fission in astroglial loss. Thus, the present findings suggest that the differential astroglial mitochondrial dynamics may participate in the distinct characteristics of astroglial death induced by SE.

  7. Cell-Centric View of Apoptosis and Apoptotic Cell Death-Inducing Antitumoral Strategies

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    Maria Dolores Boyano

    2011-03-01

    Full Text Available Programmed cell death and especially apoptotic cell death, occurs under physiological conditions and is also desirable under pathological circumstances. However, the more we learn about cellular signaling cascades, the less plausible it becomes to find restricted and well-limited signaling pathways. In this context, an extensive description of pathway-connections is necessary in order to point out the main regulatory molecules as well as to select the most appropriate therapeutic targets. On the other hand, irregularities in programmed cell death pathways often lead to tumor development and cancer-related mortality is projected to continue increasing despite the effort to develop more active and selective antitumoral compounds. In fact, tumor cell plasticity represents a major challenge in chemotherapy and improvement on anticancer therapies seems to rely on appropriate drug combinations. An overview of the current status regarding apoptotic pathways as well as available chemotherapeutic compounds provides a new perspective of possible future anticancer strategies.

  8. RX871024 reduces NO production but does not protect against pancreatic beta-cell death induced by proinflammatory cytokines

    DEFF Research Database (Denmark)

    Zaitseva, Irina I; Sharoyko, Vladimir; Størling, Joachim;

    2006-01-01

    cytokines and correlated with the decrease in p38 MAPK phosphorylation. Conversely, efaroxan did not affect cytokine-induced NO production. Our data indicate that a combination of pro-inflammatory cytokines IL-1beta, IFNgamma, and TNFalpha, conditions modelling those that take place in type 1 diabetes...... of the cytokines IL-1beta, IFNgamma, and TNFalpha. To address this issue, experiments involving different methods for detection of cell death, different concentrations of the cytokines, and a variety of conditions of preparation and culturing of ob/ob mouse islets and beta-cells have been carried out. Thoroughly...... performed experiments have not been able to demonstrate a protective effect of RX871024 and efaroxan on beta-cell death induced by the combination of cytokines. However, the inhibitory effect of RX871024 on NO production in ob/ob mouse islets and beta-cells was still observed in the presence of all three...

  9. CNOT3 suppression promotes necroptosis by stabilizing mRNAs for cell death-inducing proteins

    Science.gov (United States)

    Suzuki, Toru; Kikuguchi, Chisato; Sharma, Sahil; Sasaki, Toshio; Tokumasu, Miho; Adachi, Shungo; Natsume, Tohru; Kanegae, Yumi; Yamamoto, Tadashi

    2015-01-01

    The CCR4-NOT complex is conserved in eukaryotes and is involved in mRNA metabolism, though its molecular physiological roles remain to be established. We show here that CNOT3-depleted mouse embryonic fibroblasts (MEFs) undergo cell death. Levels of other complex subunits are decreased in CNOT3-depleted MEFs. The death phenotype is rescued by introduction of wild-type (WT), but not mutated CNOT3, and is not suppressed by the pan-caspase inhibitor, zVAD-fluoromethylketone. Gene expression profiling reveals that mRNAs encoding cell death-related proteins, including receptor-interacting protein kinase 1 (RIPK1) and RIPK3, are stabilized in CNOT3-depleted MEFs. Some of these mRNAs bind to CNOT3, and in the absence of CNOT3 their poly(A) tails are elongated. Inhibition of RIPK1-RIPK3 signaling by a short-hairpin RNA or a necroptosis inhibitor, necrostatin-1, confers viability upon CNOT3-depleted MEFs. Therefore, we conclude that CNOT3 targets specific mRNAs to prevent cells from being disposed to necroptotic death. PMID:26437789

  10. Characterisation of cell death inducing Phytophthora capsici CRN effectors suggests diverse activities in the host nucleus

    Directory of Open Access Journals (Sweden)

    Remco eStam

    2013-10-01

    Full Text Available Plant-Microbe interactions are complex associations that feature recognition of Pathogen Associated Molecular Patterns by the plant immune system and dampening of subsequent responses by pathogen encoded secreted effectors. With large effector repertoires now identified in a range of sequenced microbial genomes, much attention centres on understanding their roles in immunity or disease. These studies not only allow identification of pathogen virulence factors and strategies, they also provide an important molecular toolset suited for studying immunity in plants. The Phytophthora intracellular effector repertoire encodes a large class of proteins that translocate into host cells and exclusively target the host nucleus. Recent functional studies have implicated the CRN protein family as an important class of diverse effectors that target distinct subnuclear compartments and modify host cell signalling. Here, we characterised three necrosis inducing CRNs and show that there are differences in the levels of cell death. We show that only expression of CRN20_624 has an additive effect on PAMP induced cell death but not AVR3a induced ETI. Given their distinctive phenotypes, we assessed localisation of each CRN with a set of nuclear markers and found clear differences in CRN subnuclear distribution patterns. These assays also revealed that expression of CRN83_152 leads to a distinct change in nuclear chromatin organisation, suggesting a distinct series of events that leads to cell death upon over-expression. Taken together, our results suggest diverse functions carried by CRN C-termini, which can be exploited to identify novel processes that take place in the host nucleus and are required for immunity or susceptibility.

  11. Apoptotic Cell Death Induced by Resveratrol Is Partially Mediated by the Autophagy Pathway in Human Ovarian Cancer Cells.

    Directory of Open Access Journals (Sweden)

    Fangfang Lang

    Full Text Available Resveratrol (trans-3,4,5'-trihydroxystilbene is an active compound in food, such as red grapes, peanuts, and berries. Resveratrol exhibits an anticancer effect on various human cancer cells. However, the mechanism of resveratrol-induced anti-cancer effect at the molecular level remains to be elucidated. In this study, the mechanism underlying the anti-cancer effect of resveratrol in human ovarian cancer cells (OVCAR-3 and Caov-3 was investigated using various molecular biology techniques, such as flow cytometry, western blotting, and RNA interference, with a major focus on the potential role of autophagy in resveratrol-induced apoptotic cell death. We demonstrated that resveratrol induced reactive oxygen species (ROS generation, which triggers autophagy and subsequent apoptotic cell death. Resveratrol induced ATG5 expression and promoted LC3 cleavage. The apoptotic cell death induced by resveratrol was attenuated by both pharmacological and genetic inhibition of autophagy. The autophagy inhibitor chloroquine, which functions at the late stage of autophagy, significantly reduced resveratrol-induced cell death and caspase 3 activity in human ovarian cancer cells. We also demonstrated that targeting ATG5 by siRNA also suppressed resveratrol-induced apoptotic cell death. Thus, we concluded that a common pathway between autophagy and apoptosis exists in resveratrol-induced cell death in OVCAR-3 human ovarian cancer cells.

  12. Cell death induced on cell cultures and nude mouse skin by non-thermal, nanosecond-pulsed generated plasma.

    Directory of Open Access Journals (Sweden)

    Arnaud Duval

    Full Text Available Non-thermal plasmas are gaseous mixtures of molecules, radicals, and excited species with a small proportion of ions and energetic electrons. Non-thermal plasmas can be generated with any high electro-magnetic field. We studied here the pathological effects, and in particular cell death, induced by nanosecond-pulsed high voltage generated plasmas homogeneously applied on cell cultures and nude mouse skin. In vitro, Jurkat cells and HMEC exhibited apoptosis and necrosis, in dose-dependent manner. In vivo, on nude mouse skin, cell death occurred for doses above 113 J/cm(2 for the epidermis, 281 J/cm(2 for the dermis, and 394 J/cm(2 for the hypodermis. Using electron microscopy, we characterized apoptosis for low doses and necrosis for high doses. We demonstrated that these effects were not related to thermal, photonic or pH variations, and were due to the production of free radicals. The ability of cold plasmas to generate apoptosis on cells in suspension and, without any sensitizer, on precise skin areas, opens new fields of application in dermatology for extracorporeal blood cell treatment and the eradication of superficial skin lesions.

  13. Hepatitis C virus-induced degradation of cell death-inducing DFFA-like effector B leads to hepatic lipid dysregulation

    OpenAIRE

    Lee, Emily M.; Alsagheir, Ali; Wu, Xianfang; Hammack, Christy; McLauchlan, John; Watanabe, Noriyuki; Wakita, Takaji; Kneteman, Norman M; Douglas, Donna N.; Tang, Hengli

    2016-01-01

    Chronically infected hepatitis C individuals commonly exhibit hepatic intracellular lipid accumulation, termed steatosis. Hepatitis C virus (HCV) infection perturbs host lipid metabolism through both cellular and viral-induced mechanisms, with the viral core protein playing an important role in steatosis development. We have recently identified a liver protein, the cell death-inducing DFFA-like effector B (CIDEB), as a HCV entry host dependence factor that is downregulated by HCV infection in...

  14. Role of SIRT1-mediated mitochondrial and Akt pathways in glioblastoma cell death induced by Cotinus coggygria flavonoid nanoliposomes

    Directory of Open Access Journals (Sweden)

    Wang G

    2015-08-01

    phosphorylated p53. Together, these results indicated SIRT1/p53-mediated cell death was induced by CCF-NLs, but not by extracellular signal-regulated kinase, in DBTRG-05MG cells. Overall, this study suggested caspase-dependent activation of both the intrinsic and extrinsic signaling pathways, probably through blockade of the SIRT1/p53-mediated mitochondrial and Akt pathways to exert the proapoptotic effect of CCF-NLs in DBTRG-05MG GBM cells. Keywords: Cotinus coggygria flavonoid nanoliposomes, cell death, SIRT1, mitochondrial, PI3K/Akt pathway

  15. Tat-NOL3 protects against hippocampal neuronal cell death induced by oxidative stress through the regulation of apoptotic pathways.

    Science.gov (United States)

    Sohn, Eun Jeong; Shin, Min Jea; Eum, Won Sik; Kim, Dae Won; Yong, Ji In; Ryu, Eun Ji; Park, Jung Hwan; Cho, Su Bin; Cha, Hyun Ju; Kim, Sang Jin; Yeo, Hyeon Ji; Yeo, Eun Ji; Choi, Yeon Joo; Im, Seung Kwon; Kweon, Hae Young; Kim, Duk-Soo; Yu, Yeon Hee; Cho, Sung-Woo; Park, Meeyoung; Park, Jinseu; Cho, Yong-Jun; Choi, Soo Young

    2016-07-01

    Oxidative stress-induced apoptosis is associated with neuronal cell death and ischemia. The NOL3 [nucleolar protein 3 (apoptosis repressor with CARD domain)] protein protects against oxidative stress-induced cell death. However, the protective mechanism responsible for this effect as well as the effects of NOL3 against oxidative stress in ischemia remain unclear. Thus, we examined the protective effects of NOL3 protein on hydrogen peroxide (H2O2)-induced oxidative stress and the mechanism responsible for these effects in hippocampal neuronal HT22 cells and in an animal model of forebrain ischemia using Tat-fused NOL3 protein (Tat-NOL3). Purified Tat-NOL3 protein transduced into the H2O2-exposed HT22 cells and inhibited the production of reactive oxygen species (ROS), DNA fragmentation and reduced mitochondrial membrane potential (ΔΨm). In addition, Tat-NOL3 prevented neuronal cell death through the regulation of apoptotic signaling pathways including Bax, Bcl-2, caspase-2, -3 and -8, PARP and p53. In addition, Tat-NOL3 protein transduced into the animal brains and significantly protected against neuronal cell death in the CA1 region of the hippocampus by regulating the activation of microglia and astrocytes. Taken together, these findings demonstrate that Tat-NOL3 protein protects against oxidative stress-induced neuronal cell death by regulating oxidative stress and by acting as an anti-apoptotic protein. Thus, we suggest that Tat-NOL3 represents a potential therapeutic agent for protection against ischemic brain injury. PMID:27221790

  16. The Ketone Body, β-Hydroxybutyrate Stimulates the Autophagic Flux and Prevents Neuronal Death Induced by Glucose Deprivation in Cortical Cultured Neurons.

    Science.gov (United States)

    Camberos-Luna, Lucy; Gerónimo-Olvera, Cristian; Montiel, Teresa; Rincon-Heredia, Ruth; Massieu, Lourdes

    2016-03-01

    Glucose is the major energy substrate in brain, however, during ketogenesis induced by starvation or prolonged hypoglycemia, the ketone bodies (KB), acetoacetate and β-hydroxybutyrate (BHB) can substitute for glucose. KB improve neuronal survival in diverse injury models, but the mechanisms by which KB prevent neuronal damage are still not well understood. In the present study we have investigated whether protection by the D isomer of BHB (D-BHB) against neuronal death induced by glucose deprivation (GD), is related to autophagy. Autophagy is a lysosomal-dependent degradation process activated during nutritional stress, which leads to the digestion of damaged proteins and organelles providing energy for cell survival. Results show that autophagy is activated in cortical cultured neurons during GD, as indicated by the increase in the levels of the lipidated form of the microtubule associated protein light chain 3 (LC3-II), and the number of autophagic vesicles. At early phases of glucose reintroduction (GR), the levels of p62 declined suggesting that the degradation of the autophagolysosomal content takes place at this time. In cultures exposed to GD and GR in the presence of D-BHB, the levels of LC3-II and p62 rapidly declined and remained low during GR, suggesting that the KB stimulates the autophagic flux preventing autophagosome accumulation and improving neuronal survival.

  17. Cell-death-inducing DFFA-like Effector B Contributes to the Assembly of Hepatitis C Virus (HCV) Particles and Interacts with HCV NS5A

    Science.gov (United States)

    Cai, Hua; Yao, Wenxia; Li, Leike; Li, Xinlei; Hu, Longbo; Mai, Runming; Peng, Tao

    2016-01-01

    Hepatitis C virus (HCV) uses components of the very-low-density lipoprotein (VLDL) pathway for assembly/release. We previously reported that hepatocyte nuclear factor 4α (HNF4α) participates in HCV assembly/release through downstream factors those participate in VLDL assembly/secretion. Cell-death-inducing DFFA-like effector B (CIDEB) is an important regulator of the VLDL pathway. CIDEB is required for entry of HCV particles from cell culture (HCVcc), but the effects of CIDEB on the post-entry steps of the HCV lifecycle are unclear. In the present study, we determined that CIDEB is required for HCV assembly in addition to HCVcc entry. Furthermore, CIDEB interacts with the HCV NS5A protein, and the N terminus of CIDEB and the domain I of NS5A are involved in this interaction. Moreover, CIDEB silencing impairs the association of apolipoprotein E (ApoE) with HCV particles. Interestingly, CIDEB is also required for the post-entry stages of the dengue virus (DENV) life cycle. Collectively, these results indicate that CIDEB is a new host factor that is involved in HCV assembly, presumably by interacting with viral protein, providing new insight into the exploitation of the VLDL regulator CIDEB by HCV. PMID:27282740

  18. Differential Roles of Cell Death-inducing DNA Fragmentation Factor-α-like Effector (CIDE) Proteins in Promoting Lipid Droplet Fusion and Growth in Subpopulations of Hepatocytes.

    Science.gov (United States)

    Xu, Wenyi; Wu, Lizhen; Yu, Miao; Chen, Feng-Jung; Arshad, Muhammad; Xia, Xiayu; Ren, Hao; Yu, Jinhai; Xu, Li; Xu, Dijin; Li, John Zhong; Li, Peng; Zhou, Linkang

    2016-02-26

    Lipid droplets (LDs) are dynamic subcellular organelles whose growth is closely linked to obesity and hepatic steatosis. Cell death-inducing DNA fragmentation factor-α-like effector (CIDE) proteins, including Cidea, Cideb, and Cidec (also called Fsp27), play important roles in lipid metabolism. Cidea and Cidec are LD-associated proteins that promote atypical LD fusion in adipocytes. Here, we find that CIDE proteins are all localized to LD-LD contact sites (LDCSs) and promote lipid transfer, LD fusion, and growth in hepatocytes. We have identified two types of hepatocytes, one with small LDs (small LD-containing hepatocytes, SLHs) and one with large LDs (large LD-containing hepatocytes, LLHs) in the liver. Cideb is localized to LDCSs and promotes lipid exchange and LD fusion in both SLHs and LLHs, whereas Cidea and Cidec are specifically localized to the LDCSs and promote lipid exchange and LD fusion in LLHs. Cideb-deficient SLHs have reduced LD sizes and lower lipid exchange activities. Fasting dramatically induces the expression of Cidea/Cidec and increases the percentage of LLHs in the liver. The majority of the hepatocytes from the liver of obese mice are Cidea/Cidec-positive LLHs. Knocking down Cidea or Cidec significantly reduced lipid storage in the livers of obese animals. Our data reveal that CIDE proteins play differential roles in promoting LD fusion and lipid storage; Cideb promotes lipid storage under normal diet conditions, whereas Cidea and Cidec are responsible for liver steatosis under fasting and obese conditions.

  19. A novel neuron-enriched protein SDIM1 is down regulated in Alzheimer's brains and attenuates cell death induced by DNAJB4 over-expression in neuro-progenitor cells

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    Lei Joy X

    2011-01-01

    Full Text Available Abstract Background Molecular changes in multiple biological processes contribute to the development of chronic neurodegeneration such as late onset Alzheimer's disease (LOAD. To discover how these changes are reflected at the level of gene expression, we used a subtractive transcription-based amplification of mRNA procedure to identify novel genes that have altered expression levels in the brains of Alzheimer's disease (AD patients. Among the genes altered in expression level in AD brains was a transcript encoding a novel protein, SDIM1, that contains 146 amino acids, including a typical signal peptide and two transmembrane domains. Here we examined its biochemical properties and putative roles in neuroprotection/neurodegeneration. Results QRT-PCR analysis of additional AD and control post-mortem human brains showed that the SDIM1 transcript was indeed significantly down regulated in all AD brains. SDIM1 is more abundant in NT2 neurons than astrocytes and present throughout the cytoplasm and neural processes, but not in the nuclei. In NT2 neurons, it is highly responsive to stress conditions mimicking insults that may cause neurodegeneration in AD brains. For example, SDIM1 was significantly down regulated 2 h after oxygen-glucose deprivation (OGD, though had recovered 16 h later, and also appeared significantly up regulated compared to untreated NT2 neurons. Overexpression of SDIM1 in neuro-progenitor cells improved cells' ability to survive after injurious insults and its downregulation accelerated cell death induced by OGD. Yeast two-hybrid screening and co-immunoprecipitation approaches revealed, both in vitro and in vivo, an interaction between SDIM1 and DNAJB4, a heat shock protein hsp40 homolog, recently known as an enhancer of apoptosis that also interacts with the mu opioid receptor in human brain. Overexpression of DNAJB4 alone significantly reduced cell viability and SDIM1 co-overexpression was capable of attenuating the cell death

  20. Cell-to-Cell stochastic fluctuations in apoptotic signaling can decide between life and death

    CERN Document Server

    Raychaudhuri, S; Nguyen, T; Khan, E M; Goldkorn, T

    2007-01-01

    Apoptosis, or genetically programmed cell death, is a crucial cellular process that maintains the balance between life and death in cells. The precise molecular mechanism of apoptosis signaling and how these two pathways are differentially activated under distinct apoptotic stimuli is poorly understood. We developed a Monte Carlo-based stochastic simulation model that can characterize distinct signaling behaviors in the two major pathways of apoptotic signaling using a novel probability distribution-based approach. Specifically, we show that for a weak death signal, such as low levels of death ligand Fas (CD95) binding or under stress conditions, the type 2 mitochondrial pathway dominates apoptotic signaling. Our results also show signaling in the type 2 pathway is stochastic, where the population average over many cells does not capture the cell-to-cell fluctuations in the time course (~1 - 10 hours) of downstream caspase-3 activation. On the contrary, the probability distribution of caspase-3 activation for...

  1. CHIP, a carboxy terminus HSP-70 interacting protein, prevents cell death induced by endoplasmic reticulum stress in the central nervous system.

    Science.gov (United States)

    Cabral Miranda, Felipe; Adão-Novaes, Juliana; Hauswirth, William W; Linden, Rafael; Petrs-Silva, Hilda; Chiarini, Luciana B

    2014-01-01

    Endoplasmic reticulum (ER) stress and protein misfolding are associated with various neurodegenerative diseases. ER stress activates unfolded protein response (UPR), an adaptative response. However, severe ER stress can induce cell death. Here we show that the E3 ubiquitin ligase and co-chaperone Carboxyl Terminus HSP70/90 Interacting Protein (CHIP) prevents neuron death in the hippocampus induced by severe ER stress. Organotypic hippocampal slice cultures (OHSCs) were exposed to Tunicamycin, a pharmacological ER stress inducer, to trigger cell death. Overexpression of CHIP was achieved with a recombinant adeno-associated viral vector (rAAV) and significantly diminished ER stress-induced cell death, as shown by analysis of propidium iodide (PI) uptake, condensed chromatin, TUNEL and cleaved caspase 3 in the CA1 region of OHSCs. In addition, overexpression of CHIP prevented upregulation of both CHOP and p53 both pro-apoptotic pathways induced by ER stress. We also detected an attenuation of eIF2a phosphorylation promoted by ER stress. However, CHIP did not prevent upregulation of BiP/GRP78 induced by UPR. These data indicate that overexpression of CHIP attenuates ER-stress death response while maintain ER stress adaptative response in the central nervous system. These results indicate a neuroprotective role for CHIP upon UPR signaling. CHIP emerge as a candidate for clinical intervention in neurodegenerative diseases associated with ER stress.

  2. Increased cerebrospinal fluid concentrations of soluble Fas (CD95/Apo-1) in hydrocephalus

    Science.gov (United States)

    Felderhoff-Mueser, U; Herold, R; Hochhaus, F; Koehne, P; Ring-Mrozik, E; Obladen, M; Buhrer, C

    2001-01-01

    BACKGROUND AND AIMS—The ventricular enlargement observed in children with chronically raised intracranial pressure (ICP) causes a secondary loss of brain tissue. In animal studies of hydrocephalus, programmed cell death (apoptosis) has been found as a major mechanism of neuronal injury. One of the regulators of the apoptotic cell death programme is the receptor mediated Fas/Fas ligand interaction.
METHODS—The apoptosis regulating cytokines soluble Fas (sFas) and soluble Fas ligand (sFasL) were studied in the cerebrospinal fluid (CSF) of 31 hydrocephalic children undergoing shunt surgery for symptomatic hydrocephalus and 18controls.
RESULTS—High concentrations of sFas were observed in children with hydrocephalus (median 252 ng/ml); in controls sFas was below the detection limit (0.5 ng/ml). sFasL was undetectable in all but one sample.
CONCLUSION—High concentrations of sFas in the CSF of children with hydrocephalus suggest intrinsic sFas production, potentially antagonising pressure mediated Fas activation.

 PMID:11259245

  3. Expression of FAS/APO 1/CD 95 in thyroid tumors.

    Directory of Open Access Journals (Sweden)

    Waldemar Balcerzak

    2007-06-01

    Full Text Available Using immunohistochemistry, Fas/Apo-1 protein expression was investigated in thyroid cancers of 67 patients. Thyroid biopsies from twenty eight patients with benign thyroid diseases were also examined. The patients with thyroid cancer manifested a variable histology of the cancer, including 14 patients with follicular carcinoma, 48 with papillary carcinoma, 5 patients with medullary carcinoma. The benign thyroid disease involved nodular goitre in 11 patients and follicular adenoma in other 17 patients. The study aimed at examining immunohistochemical expression of Fas protein in order to determine whether the level of its expression correlated with histological diagnosis. In individual patients Fas expression was more prevalent in thyroid carcinomas as compared to benign tumors (p=0.001. A marked increase in Fas expression was found in papillary carcinoma, as compared to follicular and medullary carcinomas (p=0.02. In conclusion, Fas was significantly more frequently overexpressed in thyroid cancer, indicating its role in thyroid tumorigenesis.

  4. In vivo UVB irradiation induces clustering of Fas (CD95) on human epidermal cells

    DEFF Research Database (Denmark)

    Bang, Bo; Gniadecki, Robert; Larsen, Jørgen K;

    2003-01-01

    In vitro studies with human cell lines have demonstrated that the death receptor Fas plays a role in ultraviolet (UV)-induced apoptosis. The purpose of the present study was to investigate the relation between Fas expression and apoptosis as well as clustering of Fas in human epidermis after......=4). Apoptosis was demonstrated by the TUNEL reaction, and the maximum of apoptotic cells was detected at 48 h after irradiation. Double-staining of Fas and TUNEL showed that apoptosis was restricted to the Fas-positive epidermal subpopulation, but there was no correlation between the intensities...... of Fas expression and TUNEL reaction. Median expression intensity of FasL-positive cells transiently decreased to 0.9- and 0.8-fold of the preirradiation respective level after 24 h and 48 h, respectively, and returned to the respective preirradiation level at 72 h after irradiation (n=4). Concentrations...

  5. Human Melanoma Cells Do Not Express Fas (Apo-1/CD95) Ligand

    OpenAIRE

    Chappell, Dale B.; Zaks, Tal Z.; Rosenberg, Steven A.; Restifo, Nicholas P

    1999-01-01

    A recent report described the expression of Fas ligand (FasL) by melanoma cells as an important mechanism involved in the immune evasion by tumors [M. Hahne et al., Science (Washington DC), 274: 1363–1366, 1996]. To investigate the expression of FasL by melanomas, we screened a panel of early-passage cell lines by functional assay and reverse transcriptase-PCR. Using conditions designed to replicate those in the original report, we did not find functional FasL on any of the 19 human melanoma ...

  6. Antiproliferative Activity of Cinnamomum cassia Constituents and Effects of Pifithrin-Alpha on Their Apoptotic Signaling Pathways in Hep G2 Cells

    Directory of Open Access Journals (Sweden)

    Lean-Teik Ng

    2011-01-01

    Full Text Available Cinnamaldehyde (Cin, cinnamic acid (Ca and cinnamyl alcohol (Cal, major constituents of Cinnamomum cassia, have been shown to possess antioxidant, anti-inflammatory, anticancer and other activities. In this study, our aim was to evaluate the antiproliferative activity of these compounds in human hepatoma Hep G2 cells and examine the effects of pifithrin-alpha (PFTα; a specific p53 inhibitor on their apoptotic signaling transduction mechanism. The antiproliferative activity was measured by XTT assay. Expression of apoptosis-related proteins was detected by western blotting. Results showed that at a concentration of 30 μM, the order of antiproliferative activity in Hep G2 cells was Cin > Ca > Cal. Cin (IC50 9.76 ± 0.67 μM demonstrated an antiproliferative potency as good as 5-fluorouracil (an anti-cancer drug; IC50 9.57 ± 0.61 μM. Further studies on apoptotic mechanisms of Cin showed that it downregulated the expression of Bcl-XL, upregulated CD95 (APO-1, p53 and Bax proteins, as well as cleaving the poly (ADP-ribose polymerase (PARP in a time-dependent pattern. PFTα pre-incubation significantly diminished the effect of Cin-induced apoptosis. It markedly upregulated the anti-apoptotic (Bcl-XL expression and downregulated the pro-apoptotic (Bax expression, as well as effectively blocking the CD95 (APO-1 and p53 expression, and PARP cleavage in Cin-treated cells. This study indicates that Cin was the most potent antiproliferative constituent of C. cassia, and its apoptotic mechanism in Hep G2 cells could be mediated through the p53 induction and CD95 (APO-1 signaling pathways.

  7. Acute cold exposure-induced down-regulation of CIDEA, cell death-inducing DNA fragmentation factor-alpha-like effector A, in rat interscapular brown adipose tissue by sympathetically activated beta3-adrenoreceptors.

    Science.gov (United States)

    Shimizu, Takahiro; Yokotani, Kunihiko

    2009-09-18

    The thermogenic activity of brown adipose tissue (BAT) largely depends on the mitochondrial uncoupling protein 1 (UCP1), which is up-regulated by environmental alterations such as cold. Recently, CIDEA (cell death-inducing DNA fragmentation factor-alpha-like effector A) has also been shown to be expressed at high levels in the mitochondria of BAT. Here we examined the effect of cold on the mRNA and protein levels of CIDEA in interscapular BAT of conscious rats with regard to the sympathetic nervous system. Cold exposure (4 degrees C for 3h) elevated the plasma norepinephrine level and increased norepinephrine turnover in BAT. Cold exposure resulted in down-regulation of the mRNA and protein levels of CIDEA in BAT, accompanied by up-regulation of mRNA and protein levels of UCP1. The cold exposure-induced changes of CIDEA and UCP1 were attenuated by intraperitoneal pretreatment with propranolol (a non-selective beta-adrenoreceptor antagonist) (2mg/animal) or SR59230A (a selective beta(3)-adrenoreceptor antagonist) (2mg/animal), respectively. These results suggest that acute cold exposure resulted in down-regulation of CIDEA in interscapular BAT by sympathetically activated beta(3)-adrenoreceptor-mediated mechanisms in rats.

  8. Analysis of cell death inducing compounds

    DEFF Research Database (Denmark)

    Spicker, Jeppe; Pedersen, Henrik Toft; Nielsen, Henrik Bjørn;

    2007-01-01

    Biomarkers for early detection of toxicity hold the promise of improving the failure rates in drug development. In the present study, gene expression levels were measured using full-genome RAE230 version 2 Affymetrix GeneChips on rat liver tissue 48 h after administration of six different compounds......), ornithine aminotransferase (OAT) and Cytochrome P450, subfamily IIC (mephenytoin 4-hydroxylase) (Cyp2C29). RT-PCR for these three genes was performed and four additional compounds were included for validation. The quantitative RT-PCR analysis confirmed the findings based on the microarray data and using the...... three genes a classification rate of 55 of 57 samples was achieved for the classification of not toxic versus toxic. The single most promising biomarker (OAT) alone resulted in a surprisingly 100% correctly classified samples. OAT has not previously been linked to toxicity and cell death in the...

  9. Analysis of cell death inducing compounds.

    Science.gov (United States)

    Spicker, Jeppe S; Pedersen, Henrik Toft; Nielsen, Henrik Bjørn; Brunak, Søren

    2007-11-01

    Biomarkers for early detection of toxicity hold the promise of improving the failure rates in drug development. In the present study, gene expression levels were measured using full-genome RAE230 version 2 Affymetrix GeneChips on rat liver tissue 48 h after administration of six different compounds, three toxins (ANIT, DMN and NMF) and three non-toxins (Caeruelein, Dinitrophenol and Rosiglitazone). We identified three gene transcripts with exceptional predictive performance towards liver toxicity and/or changes in histopathology. The three genes were: glucokinase regulatory protein (GCKR), ornithine aminotransferase (OAT) and Cytochrome P450, subfamily IIC (mephenytoin 4-hydroxylase) (Cyp2C29). RT-PCR for these three genes was performed and four additional compounds were included for validation. The quantitative RT-PCR analysis confirmed the findings based on the microarray data and using the three genes a classification rate of 55 of 57 samples was achieved for the classification of not toxic versus toxic. The single most promising biomarker (OAT) alone resulted in a surprisingly 100% correctly classified samples. OAT has not previously been linked to toxicity and cell death in the literature and the novel finding represents a putative hepatotoxicity biomarker. PMID:17503021

  10. Apoptosis signaling pathways and lymphocyte homeostasis

    Institute of Scientific and Technical Information of China (English)

    Guangwu Xu; Yufang Shi

    2007-01-01

    It has been almost three decades since the term "apoptosis" was first coined to describe a unique form of cell death that involves orderly, gene-dependent cell disintegration. It is now well accepted that apoptosis is an essential life process for metazoan animals and is critical for the formation and function of tissues and organs. In the adult mammalian body, apoptosis is especially important for proper functioning of the immune system. In recent years, along with the rapid advancement of molecular and cellular biology, great progress has been made in understanding the mechanisms leading to apoptosis. It is generally accepted that there are two major pathways of apoptotic cell death induction: extrinsic signaling through death receptors that leads to the formation of the death-inducing signaling complex (DISC), and intrinsic signaling mainly through mitochondria which leads to the formation of the apoptosome. Formation of the DISC or apoptosome, respectively, activates initiator and common effector caspases that execute the apoptosis process. In the immune system, both pathways operate; however, it is not known whether they are sufficient to maintain lymphocyte homeostasis. Recently, new apoptotic mechanisms including caspase-independent pathways and granzyme-initiated pathways have been shown to exist in lymphocytes. This review will summarize our understanding of the mechanisms that control the homeostasis of various lymphocyte populations.

  11. Fas ligand based immunotherapy: A potent and effective neoadjuvant with checkpoint inhibitor properties, or a systemically toxic promoter of tumor growth?

    Science.gov (United States)

    Modiano, Jaime F; Bellgrau, Donald

    2016-02-01

    Fas ligand (FasL, CD95L) is a 40-kDa type II transmembrane protein that binds to Fas (CD95) receptors and promotes programmed cell death. Fas receptors are expressed at higher levels in many tumors than in normal cells; however, systemic administration of FasL or agonistic anti-Fas antibodies to mice with tumors caused lethal hepatitis. Somewhat paradoxically, elimination of Fas or FasL from tumors also leads to death induced by CD95 receptor/ligand elimination (DICE). At face value, this suggests that Fas signaling not only kills normal cells, but that it also is essential for tumor cell survival. Targeting this pathway may not only fail to kill tumors, but instead may even enhance their growth, leading some to report the demise of Fas ligand in cancer immunotherapy. But, to paraphrase Mark Twain, is this death an exaggeration? Here, we provide a careful examination of the literature exploring the merits of FasL as a novel form of cancer immunotherapy. With local administration using delivery vectors that achieve high levels of expression in the tumor environment, our results indicate that the potential for systemic toxicity is eliminated in higher mammals, and that a systemic anti-tumor response ensues, which delays or prevents progression and simultaneously attacks distant metastases.

  12. Changing of expression level of fas-antigen (CD95), cytokines synthesis and production after irradiation in low doses

    International Nuclear Information System (INIS)

    It is known that bone marrow progenitor (CD34+), tymocytes and peripheral blood lymphocytes (PBL) are most radiosensitive than other cell types. Even low doses of radiation induce apoptosis. The investigators suggest that it is possible relationship between synthesis and production of cytokines and apoptotic process. With the purpose to determine correlation between expression of Fas-antigen and synthesis of cytokines after low doses irradiation the experiments by irradiation PBL of healthy persons in vitro were held. Cells were X-irradiated by 12,5, 25 and 50 cGy. In consequence of the experiments increasing of Fas-antigen was revealed. This increasing correlated with changing in synthesis and production of cytokines. Also the Chernobyl's accident liquidators (CAL) were investigated. After comparison data in the group CAL (I) with data in the control group (II) increasing of Fas-antigen expression was revealed. Also in I group was discovered increasing of the cell number sinthesied interleukine-4 (IL-4) and interleukine-6 (IL-6). Interleukine-lβ (IL-1 β) producing pell were decreased. These changes have been correlated with degree of immunodeficiency at CAL. These data allow to consider the apoptosis as cell mechanism included in pathogenesis of diseases, which can be showed later long time after irradiation. (author)

  13. Molecular mechanisms mediating the neuroproyective effects of quinacrine and minocycline on cell death induced by the prion protein fragment 90-231 (hPrP90-231

    Directory of Open Access Journals (Sweden)

    V. Villa

    2011-01-01

    Full Text Available The effects of quinacrine and minocycline on the toxicity induced by hPrP90-231 were studied. By mild thermal denaturation, hPrP90-231 can be converted in a toxic PrPSc-like structure affecting the survival of SH-SY5Y cells. Quinacrine and minocycline prevented hPrP90-231-induced toxicity interfering with different mechanisms: protective effects of quinacrine are mediated by the binding to the fragment that abolished hPrP90-231 structural changes and cell internalization, whereas, minocycline reverted MAP kinase neurotoxic signaling exerted by the prion fragment.

  14. Prosocial Signalling

    DEFF Research Database (Denmark)

    Kahsay, Goytom Abraha

    suggested that consumers pay price premium because this sends the signal that the consumer has prosocial preferences and a few empirical studies have documented that reputation plays a key role when consumers choose products containing prosocial components. However, little is known about consumers...... consumer goods and presents empirical evidences from a natural consumption data. This thesis also investigates consumers’ behaviour under a newly introduced pricing system called Pay-What-You-Want (PWYW) and investigates empirically whether reputation signalling can be used as a policy instrument in other...... on the role of social network in facilitating factor input transactions and the role of reputation in reducing enforcement. Finally, the third part consists of one paper which is concerned with investigating the effect of climate change and adaptation policy on agricultural production in Eastern Africa...

  15. Auxin signaling

    OpenAIRE

    Quint, Marcel; Gray, William M.

    2006-01-01

    Auxin regulates a host of plant developmental and physiological processes, including embryogenesis, vascular differentiation, organogenesis, tropic growth, and root and shoot architecture. Genetic and biochemical studies carried out over the past decade have revealed that much of this regulation involves the SCFTIR1/AFB-mediated proteolysis of the Aux/IAA family of transcriptional regulators. With the recent finding that the TRANSPORT INHIBITOR RESPONSE1 (TIR1)/AUXIN SIGNALING F-BOX (AFB) pro...

  16. Concurrent MEK and autophagy inhibition is required to restore cell death associated danger-signalling in Vemurafenib-resistant melanoma cells.

    Science.gov (United States)

    Martin, S; Dudek-Perić, A M; Maes, H; Garg, A D; Gabrysiak, M; Demirsoy, S; Swinnen, J V; Agostinis, P

    2015-02-01

    Vemurafenib (PLX4032), an inhibitor of BRAF(V600E), has demonstrated significant clinical anti-melanoma effects. However, the majority of treated patients develop resistance, due to a variety of molecular mechanisms including MAPK reactivation through MEK. The induction of a cancer cell death modality associated with danger-signalling resulting in surface mobilization of crucial damage-associated-molecular-patterns (DAMPs), e.g. calreticulin (CRT) and heat shock protein-90 (HSP90), from dying cells, is emerging to be crucial for therapeutic success. Both cell death and danger-signalling are modulated by autophagy, a key adaptation mechanism stimulated during melanoma progression. However, whether melanoma cell death induced by MAPK inhibition is associated with danger-signalling, and the reliance of these mechanisms on autophagy, has not yet been scrutinized. Using a panel of isogenic PLX4032-sensitive and resistant melanoma cell lines we show that PLX4032-induced caspase-dependent cell death and DAMPs exposure in the drug-sensitive cells, but failed to do so in the drug-resistant cells, displaying heightened MEK activation. MEK inhibitor, U0126, treatment sensitized PLX4032-resistant cells to death and re-established their danger-signalling capacity. Only melanoma cells exposing death-induced danger-signals were phagocytosed and induced DC maturation. Although the PLX4032-resistant melanoma cells displayed higher basal and drug-induced autophagy, compromising autophagy, pharmacologically or by ATG5 knockdown, was insufficient to re-establish their PLX4032 sensitivity. Interestingly, autophagy abrogation was particularly efficacious in boosting cell death and ecto-CRT/ecto-HSP90 in PLX4032-resistant cells upon blockage of MEK hyper-activation by U0126. Thus combination of MEK inhibitors with autophagy blockers may represent a novel treatment regime to increase both cell death and danger-signalling in Vemurafenib-resistant metastatic melanoma.

  17. The hyperanalytic signal

    CERN Document Server

    Bihan, Nicolas Le

    2010-01-01

    The concept of the analytic signal is extended from the case of a real signal with a complex analytic signal to a complex signal with a hypercomplex analytic signal (which we call a hyperanalytic signal) The hyperanalytic signal may be interpreted as an ordered pair of complex signals or as a quaternion signal. The hyperanalytic signal contains a complex orthogonal signal and we show how to obtain this by three methods: a pair of classical Hilbert transforms; a complex Fourier transform; and a quaternion Fourier transform. It is shown how to derive from the hyperanalytic signal a complex envelope and phase using a polar quaternion representation previously introduced by the authors. The complex modulation of a real sinusoidal carrier is shown to generalize the modulation properties of the classical analytic signal. The paper extends the ideas of properness to deterministic complex signals using the hyperanalytic signal. A signal example is presented, with its orthogonal signal, and its complex envelope and ph...

  18. Hepatitis C virus infection and apoptosis

    Institute of Scientific and Technical Information of China (English)

    Richard Fischer; Thomas Baumert; Hubert E Blum

    2007-01-01

    Apoptosis is central for the control and elimination of viral infections. In chronic hepatitis C virus (HCV) infection,enhanced hepatocyte apoptosis and upregulation of the death inducing ligands CD95/Fas, TRAIL and TNFα occur.Nevertheless, HCV infection persists in the majority of patients. The impact of apoptosis in chronic HCV infection is not well understood. It may be harmful by triggering liver fibrosis, or essential in interferon (IFN)induced HCV elimination. For virtually all HCV proteins,pro- and anti-apoptotic effects have been described,especially for the core and NS5A protein. To date, it is not known which HCV protein affects apoptosis in vivo and whether the infectious virions act pro- or antiapoptotic. With the availability of an infectious tissue culture system, we now can address pathophysiologically relevant issues. This review focuses on the effect of HCV infection and different HCV proteins on apoptosis and of the corresponding signaling cascades.

  19. Targeted cancer cell death induced by biofunctionalized magnetic nanowires

    KAUST Repository

    Contreras, Maria F.

    2014-02-01

    Magnetic micro and nanomaterials are increasingly interesting for biomedical applications since they possess many advantageous properties: they can become biocompatible, they can be functionalized to target specific cells and they can be remotely manipulated by magnetic fields. The goal of this study is to use antibody-functionalized nickel nanowires (Ab-NWs) as an alternative method in cancer therapy overcoming the limitations of current treatments that lack specificity and are highly cytotoxic. Ab-NWs have been incubated with cancer cells and a 12% drop on cell viability was observed for a treatment of only 10 minutes and an alternating magnetic field of low intensity and low frequency. It is believed that the Ab-NWs vibrate transmitting a mechanical force to the targeted cells inducing cell death. © 2014 IEEE.

  20. Chimera death induced by the mean-field diffusive coupling

    OpenAIRE

    Banerjee, Tanmoy

    2014-01-01

    Recently a novel dynamical state, called the {\\it chimera death}, is discovered in a network of non locally coupled identical oscillators [A. Zakharova, M. Kapeller, and E. Sch\\"oll, Phy.Rev.Lett. 112, 154101 (2014)], which is defined as the coexistence of spatially coherent and incoherent oscillation death state. This state arises due to the interplay of non locality and symmetry breaking and thus bridges the gap between two important dynamical states, namely the chimera and oscillation deat...

  1. Brain death induces apoptosis in donor liver of the rat

    NARCIS (Netherlands)

    van der Hoeven, JAB; Moshage, H; Schuurs, T; Nijboer, M; van Schilfgaarde, R; Ploeg, RJ

    2003-01-01

    Background. A difference in short- and long-term function between living-related and cadaveric donor organs is consistently shown in kidney- and liver-transplant studies. We hypothesize that this is caused by induction of apoptosis and inflammation of the potential graft because of the phase of brai

  2. Protection of Momordica charantia polysaccharide against intracerebral hemorrhage-induced brain injury through JNK3 signaling pathway.

    Science.gov (United States)

    Duan, Zhen-Zhen; Zhou, Xiao-Ling; Li, Yi-Hang; Zhang, Feng; Li, Feng-Ying; Su-Hua, Qi

    2015-01-01

    It has been well documented that Momordica charantia polysaccharide (MCP) has multiple biological effects such as immune enhancement, anti-oxidation and anti-cancer. However, the potential protective effects of MCP on stroke damage and its relative mechanisms remain unclear. Our present study demonstrated that MCP could scavenge reactive oxygen species (ROS) in intra-cerebral hemorrhage damage, significantly attenuating the neuronal death induced by thrombin in primary hippocampal neurons. Furthermore, we found that MCP prevented the activation of the c-Jun N-terminal protein kinase (JNK3), c-Jun and caspase-3, which was caused by the intra-cerebral hemorrhage injury. Taken together, our study demonstrated that MCP had a neuroprotective effect in response to intra-cerebral hemorrhage and its mechanisms involved the inhibition of JNK3 signaling pathway. PMID:25264226

  3. Role Of S-Nitrosylation In The Extrinsic Apoptotic Signalling Pathway In Cancer

    Directory of Open Access Journals (Sweden)

    Stéphanie Plenchette

    2015-08-01

    Full Text Available One of the key features of tumour cells is the acquisition of resistance to apoptosis. Thus, determining therapeutic strategies that circumvent apoptotic resistance and result in tumor regression is a challenge. One strategy to induce apoptosis is to activate death receptor signalling pathways. Members of the Tumor Necrosis Factor TNF-family death receptors ligand (TRAIL, FasL and TNF-α can originate from immune and non-immune cells. Death receptors, engaged by cognate ligands, can initiate multiple signaling pathways, which can generate diverse outcomes, including non-apoptosis-related signal. Knowledge on the molecular mechanisms (that determine death or survival of tumour cells following exposure to the TNF-family death receptors ligands have demonstrated that post-translational modifications of the signaling pathway components play a critical role in determining cell fate. Cell death can be sensed by nitric oxide (NO in a wide variety of tumour cells. S-nitrosylation, the covalent modification of a protein cysteine thiol by an NO moiety, has emerged as an important post-translational regulation for the TNF-family death receptor signaling pathways. It has been demonstrated that death receptor DR4 (TRAIL-R1 becomes S-nitrosylated and promotes apoptosis following a specific NO donor treatment (Tang et al., 2006. Then, our group has shown that S-nitrosylation of Fas, following glyceryl trinitrate (GTN exposure, promotes redistribution of the receptor to lipid rafts, formation of the death-inducing signal complex (DISC, and induction of cell death. Finally, I will discuss our recent efforts to decipher regulatory mechanism of the TNF-α/TNFR1 signalling cell death pathway by S-nitrosylation following GTN treatment.

  4. Hedgehog pathway signaling regulates human colon carcinoma HT-29 epithelial cell line apoptosis and cytokine secretion.

    Directory of Open Access Journals (Sweden)

    Agnes N Yoshimoto

    Full Text Available The Hedgehog (Hh pathway is involved in embryogenesis and physiologic processes including cell survival and proliferation. We used the HT-29 and other human colon carcinoma cell lines to investigate Hh signaling and biological functions in colonic epithelial cells. HT-29 cells were cultured under different conditions and exposed to various stimuli. The expression of Hh pathway components and related genes and proteins were assessed by real-time PCR and immunofluorescence. Viability, apoptosis and cell proliferation were measured by the MTT assay, Annexin-V/7-AAD staining and BrdU uptake, respectively. Chemokines production was measured by ELISA in culture supernatants. Indian and Sonic Hh mRNA levels and the downstream transcription factors Gli-1 and Gli-2 increased following treatment with Hh agonists and butyrate, but decreased upon exposure to cyclopamine or GANT61. BMP4 and BMP7 expression increased after stimulation with Hh agonists. Gli-1 protein expression increased after Hh agonists and decreased following cyclopamine. Exposure to Hh agonists promoted β-catenin reduction and subcellular redistribution. Levels of IL-8 and MCP-1 decreased upon exposure to Hh agonists compared to Hh antagonists, LPS, IFN-γ or EGF. Monocyte chemotaxis decreased upon exposure to supernatants of HT-29 cells treated with Shh compared to Hh antagonists, LPS and IFN-γ. Cellular incorporation of BrdU and cell viability decreased following Hh blockade. Hh agonists abrogated the anti-CD95 induced apoptosis. Hh pathway is a key controller of colon cancer cells, as demonstrated by its effect in dampening inflammatory signals and antagonizing apoptosis. The differential expression of Hh components may underlie abnormalities in the local immune response and in epithelial barrier integrity, with potential homeostatic implications for the development of colonic inflammation and malignancies.

  5. Signal Processing of Random Physiological Signals

    CERN Document Server

    Lessard, Charles

    2006-01-01

    Signal Processing of Random Physiological Signals presents the most widely used techniques in signal and system analysis. Specifically, the book is concerned with methods of characterizing signals and systems. Author Charles Lessard provides students and researchers an understanding of the time and frequency domain processes which may be used to evaluate random physiological signals such as brainwave, sleep, respiratory sounds, heart valve sounds, electromyograms, and electro-oculograms.Another aim of the book is to have the students evaluate actual mammalian data without spending most or all

  6. Basic digital signal processing

    CERN Document Server

    Lockhart, Gordon B

    1985-01-01

    Basic Digital Signal Processing describes the principles of digital signal processing and experiments with BASIC programs involving the fast Fourier theorem (FFT). The book reviews the fundamentals of the BASIC program, continuous and discrete time signals including analog signals, Fourier analysis, discrete Fourier transform, signal energy, power. The text also explains digital signal processing involving digital filters, linear time-variant systems, discrete time unit impulse, discrete-time convolution, and the alternative structure for second order infinite impulse response (IIR) sections.

  7. Digital signal processing laboratory

    CERN Document Server

    Kumar, B Preetham

    2011-01-01

    INTRODUCTION TO DIGITAL SIGNAL PROCESSING Brief Theory of DSP ConceptsProblem SolvingComputer Laboratory: Introduction to MATLAB®/SIMULINK®Hardware Laboratory: Working with Oscilloscopes, Spectrum Analyzers, Signal SourcesDigital Signal Processors (DSPs)ReferencesDISCRETE-TIME LTI SIGNALS AND SYSTEMS Brief Theory of Discrete-Time Signals and SystemsProblem SolvingComputer Laboratory: Simulation of Continuous Time and Discrete-Time Signals and Systems ReferencesTIME AND FREQUENCY ANALYSIS OF COMMUNICATION SIGNALS Brief Theory of Discrete-Time Fourier Transform (DTFT), Discrete Fourier Transform

  8. Structural insights of homotypic interaction domains in the ligand-receptor signal transduction of tumor necrosis factor (TNF)

    Science.gov (United States)

    Park, Young-Hoon; Jeong, Mi Suk; Jang, Se Bok

    2016-01-01

    Several members of tumor necrosis factor receptor (TNFR) superfamily that these members activate caspase-8 from death-inducing signaling complex (DISC) in TNF ligand-receptor signal transduction have been identified. In the extrinsic pathway, apoptotic signal transduction is induced in death domain (DD) superfamily; it consists of a hexahelical bundle that contains 80 amino acids. The DD superfamily includes about 100 members that belong to four subfamilies: death domain (DD), caspase recruitment domain (CARD), pyrin domain (PYD), and death effector domain (DED). This superfamily contains key building blocks: with these blocks, multimeric complexes are formed through homotypic interactions. Furthermore, each DD-binding event occurs exclusively. The DD superfamily regulates the balance between death and survival of cells. In this study, the structures, functions, and unique features of DD superfamily members are compared with their complexes. By elucidating structural insights of DD superfamily members, we investigate the interaction mechanisms of DD domains; these domains are involved in TNF ligand-receptor signaling. These DD superfamily members play a pivotal role in the development of more specific treatments of cancer. [BMB Reports 2016; 49(3): 159-166] PMID:26615973

  9. Multiplexing oscillatory biochemical signals.

    Science.gov (United States)

    de Ronde, Wiet; ten Wolde, Pieter Rein

    2014-04-01

    In recent years it has been increasingly recognized that biochemical signals are not necessarily constant in time and that the temporal dynamics of a signal can be the information carrier. Moreover, it is now well established that the protein signaling network of living cells has a bow-tie structure and that components are often shared between different signaling pathways. Here we show by mathematical modeling that living cells can multiplex a constant and an oscillatory signal: they can transmit these two signals simultaneously through a common signaling pathway, and yet respond to them specifically and reliably. We find that information transmission is reduced not only by noise arising from the intrinsic stochasticity of biochemical reactions, but also by crosstalk between the different channels. Yet, under biologically relevant conditions more than 2 bits of information can be transmitted per channel, even when the two signals are transmitted simultaneously. These observations suggest that oscillatory signals are ideal for multiplexing signals. PMID:24685537

  10. Cell signaling review series

    Institute of Scientific and Technical Information of China (English)

    Aiming Lin; Zhenggang Liu

    2008-01-01

    @@ Signal transduction is pivotal for many, if not all, fundamental cellular functions including proliferation, differentiation, transformation and programmed cell death. Deregulation of cell signaling may result in certain types of cancers and other human diseases.

  11. Signal sciences workshop. Proceedings

    International Nuclear Information System (INIS)

    This meeting is aimed primarily at signal processing and controls. The technical program for the 1997 Workshop includes a variety of efforts in the Signal Sciences with applications in the Microtechnology Area a new program at LLNL and a future area of application for both Signal/Image Sciences. Special sessions organized by various individuals in Seismic and Optical Signal Processing as well as Micro-Impulse Radar Processing highlight the program, while the speakers at the Signal Processing Applications session discuss various applications of signal processing/control to real world problems. For the more theoretical, a session on Signal Processing Algorithms was organized as well as for the more pragmatic, featuring a session on Real-Time Signal Processing

  12. Retinoid signalling during embryogenesis

    NARCIS (Netherlands)

    Pijnappel, W.W.M.; Hendriks, H.F.J.; Durston, A.J.

    1996-01-01

    Conclusion: Retinoids are suspected to have multiple functions during embryogenesis, which are carried out via various different signal transduction pathways involving active retinoids and nuclear retinoid receptors. Research focuses on the identification of the retinoid signal transduction componen

  13. Danger signals in stroke.

    Science.gov (United States)

    Gelderblom, Mathias; Sobey, Christopher G; Kleinschnitz, Christoph; Magnus, Tim

    2015-11-01

    Danger molecules are the first signals released from dying tissue after stroke. These danger signals bind to receptors on immune cells that will result in their activation and the release of inflammatory and neurotoxic mediators, resulting in amplification of the immune response and subsequent enlargement of the damaged brain volume. The release of danger signals is a central event that leads to a multitude of signals and cascades in the affected and neighbouring tissue, therefore providing a potential target for therapy.

  14. Biomedical signal processing

    CERN Document Server

    Akay, Metin

    1994-01-01

    Sophisticated techniques for signal processing are now available to the biomedical specialist! Written in an easy-to-read, straightforward style, Biomedical Signal Processing presents techniques to eliminate background noise, enhance signal detection, and analyze computer data, making results easy to comprehend and apply. In addition to examining techniques for electrical signal analysis, filtering, and transforms, the author supplies an extensive appendix with several computer programs that demonstrate techniques presented in the text.

  15. Tetrapyrrole Signaling in Plants

    Science.gov (United States)

    Larkin, Robert M.

    2016-01-01

    Tetrapyrroles make critical contributions to a number of important processes in diverse organisms. In plants, tetrapyrroles are essential for light signaling, the detoxification of reactive oxygen species, the assimilation of nitrate and sulfate, respiration, photosynthesis, and programed cell death. The misregulation of tetrapyrrole metabolism can produce toxic reactive oxygen species. Thus, it is not surprising that tetrapyrrole metabolism is strictly regulated and that tetrapyrrole metabolism affects signaling mechanisms that regulate gene expression. In plants and algae, tetrapyrroles are synthesized in plastids and were some of the first plastid signals demonstrated to regulate nuclear gene expression. In plants, the mechanism of tetrapyrrole-dependent plastid-to-nucleus signaling remains poorly understood. Additionally, some of experiments that tested ideas for possible signaling mechanisms appeared to produce conflicting data. In some instances, these conflicts are potentially explained by different experimental conditions. Although the biological function of tetrapyrrole signaling is poorly understood, there is compelling evidence that this signaling is significant. Specifically, this signaling appears to affect the accumulation of starch and may promote abiotic stress tolerance. Tetrapyrrole-dependent plastid-to-nucleus signaling interacts with a distinct plastid-to-nucleus signaling mechanism that depends on GENOMES UNCUOPLED1 (GUN1). GUN1 contributes to a variety of processes, such as chloroplast biogenesis, the circadian rhythm, abiotic stress tolerance, and development. Thus, the contribution of tetrapyrrole signaling to plant function is potentially broader than we currently appreciate. In this review, I discuss these aspects of tetrapyrrole signaling.

  16. Expression of Fas Antigen (CD95 on Human Leukemic Cells and Assessment of Apoptosis on Fas+ and Fas-Samples by Flowcytometry Method

    Directory of Open Access Journals (Sweden)

    Tahereh Zieh

    2003-12-01

    Full Text Available Regulation of normal cell growth and turnover is balanced between cell pro¬liferation, cell differentiation and apoptosis.A disruption of this balance is thought to be an important event leading to carcinogenesis .One of the effector molecules in apoptosis is Fas antigen . Cross-linking of Fas by its ligand (Fas L or agonistic anti Fas antibodies induces apoptosis of cells expressing Fas on the membrane by triggering cascade of caspaces.The aim of this research was to study the percent of expression of Fas antigen on bone marrow and peripheral blood cells in 100 patients suffering from acute lymphoid and myeloid leukemia by flow cytometry method. Sample were obtained at the time of diagnosis before antileukemic therapy. Expression of Fas antigen on normal control peripheral leukocytes was also analysed.From these data, it was found that Fas antigen is expressed in all cases, but the expression level varied widely.The percentage of Fas antigen expression in all of acute lymphoid leukemia samples was below 20%, but in acute myeloid leukemia samples, 8 out of 50 cases was above 20%. In normal control samples, the mean value for monocytes was higher than granulocytes and in granulocytes higher than lymphcytes.Expression of Fas antigen in most of the leukemic cells was low and the preliminary results showed that increase in Fas antigen expression above 20% after treatment, is a favorable prognostic sign associated with increase relapse free and total survival. Thus evaluation of this antigen before, during and after treatment is recommended.

  17. Separating signal from noise

    OpenAIRE

    Lev, Nir; Peled, Ron; Peres, Yuval

    2013-01-01

    Suppose that a sequence of numbers $x_n$ (a `signal') is transmitted through a noisy channel. The receiver observes a noisy version of the signal with additive random fluctuations, $x_n + \\xi_n$, where $\\xi_n$ is a sequence of independent standard Gaussian random variables. Suppose further that the signal is known to come from some fixed space of possible signals. Is it possible to fully recover the transmitted signal from its noisy version? Is it possible to at least detect that a non-zero s...

  18. Acoustic Signal Processing

    Science.gov (United States)

    Hartmann, William M.; Candy, James V.

    Signal processing refers to the acquisition, storage, display, and generation of signals - also to the extraction of information from signals and the re-encoding of information. As such, signal processing in some form is an essential element in the practice of all aspects of acoustics. Signal processing algorithms enable acousticians to separate signals from noise, to perform automatic speech recognition, or to compress information for more efficient storage or transmission. Signal processing concepts are the building blocks used to construct models of speech and hearing. Now, in the 21st century, all signal processing is effectively digital signal processing. Widespread access to high-speed processing, massive memory, and inexpensive software make signal processing procedures of enormous sophistication and power available to anyone who wants to use them. Because advanced signal processing is now accessible to everybody, there is a need for primers that introduce basic mathematical concepts that underlie the digital algorithms. The present handbook chapter is intended to serve such a purpose.

  19. Reliable Signal Transduction

    Science.gov (United States)

    Wollman, Roy

    Stochasticity inherent to biochemical reactions (intrinsic noise) and variability in cellular states (extrinsic noise) degrade information transmitted through signaling networks. We analyzed the ability of temporal signal modulation - that is dynamics - to reduce noise-induced information loss. In the extracellular signal-regulated kinase (ERK), calcium (Ca(2 +)) , and nuclear factor kappa-B (NF- κB) pathways, response dynamics resulted in significantly greater information transmission capacities compared to nondynamic responses. Theoretical analysis demonstrated that signaling dynamics has a key role in overcoming extrinsic noise. Experimental measurements of information transmission in the ERK network under varying signal-to-noise levels confirmed our predictions and showed that signaling dynamics mitigate, and can potentially eliminate, extrinsic noise-induced information loss. By curbing the information-degrading effects of cell-to-cell variability, dynamic responses substantially increase the accuracy of biochemical signaling networks.

  20. Geometric Signal Compression

    Institute of Scientific and Technical Information of China (English)

    Kun Zhou; Hu-Jun Bao; Jiao-Ying Shi; Qun-Sheng Peng

    2004-01-01

    Compression of mesh attributes becomes a challenging problem due to the great need for efficient storage and fast transmission. This paper presents a novel geometric signal compression framework for all mesh attributes, including position coordinates, normal, color, texture, etc. Within this framework, mesh attributes are regarded as geometric signals defined on mesh surfaces. A planar parameterization algorithm is first proposed to map 3D meshes to 2D parametric meshes. Geometric signals are then transformed into 2D signals, which are sampled into 2D regular signals using an adaptive sampling method. The JPEG2000 standard for still image compression is employed to effectively encode these regular signals into compact bit-streams with high rate/distortion ratios. Experimental results demonstrate the great application potentials of this framework.

  1. Digital signal processing

    CERN Document Server

    O'Shea, Peter; Hussain, Zahir M

    2011-01-01

    In three parts, this book contributes to the advancement of engineering education and that serves as a general reference on digital signal processing. Part I presents the basics of analog and digital signals and systems in the time and frequency domain. It covers the core topics: convolution, transforms, filters, and random signal analysis. It also treats important applications including signal detection in noise, radar range estimation for airborne targets, binary communication systems, channel estimation, banking and financial applications, and audio effects production. Part II considers sel

  2. Biomedical signals and systems

    CERN Document Server

    Tranquillo, Joseph V

    2013-01-01

    Biomedical Signals and Systems is meant to accompany a one-semester undergraduate signals and systems course. It may also serve as a quick-start for graduate students or faculty interested in how signals and systems techniques can be applied to living systems. The biological nature of the examples allows for systems thinking to be applied to electrical, mechanical, fluid, chemical, thermal and even optical systems. Each chapter focuses on a topic from classic signals and systems theory: System block diagrams, mathematical models, transforms, stability, feedback, system response, control, time

  3. Signal sampling circuit

    NARCIS (Netherlands)

    Louwsma, Simon Minze; Vertregt, Maarten

    2010-01-01

    A sampling circuit for sampling a signal is disclosed. The sampling circuit comprises a plurality of sampling channels adapted to sample the signal in time-multiplexed fashion, each sampling channel comprising a respective track-and-hold circuit connected to a respective analogue to digital converte

  4. Signal sampling circuit

    NARCIS (Netherlands)

    Louwsma, Simon Minze; Vertregt, Maarten

    2011-01-01

    A sampling circuit for sampling a signal is disclosed. The sampling circuit comprises a plurality of sampling channels adapted to sample the signal in time-multiplexed fashion, each sampling channel comprising a respective track-and-hold circuit connected to a respective analogue to digital converte

  5. Growth factor signalling.

    Science.gov (United States)

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

    1999-01-01

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

  6. Multiresolution signal decomposition schemes

    NARCIS (Netherlands)

    Goutsias, J.; Heijmans, H.J.A.M.

    1998-01-01

    [PNA-R9810] Interest in multiresolution techniques for signal processing and analysis is increasing steadily. An important instance of such a technique is the so-called pyramid decomposition scheme. This report proposes a general axiomatic pyramid decomposition scheme for signal analysis and synthes

  7. Ultrahigh bandwidth signal processing

    DEFF Research Database (Denmark)

    Oxenløwe, Leif Katsuo

    2016-01-01

    Optical time lenses have proven to be very versatile for advanced optical signal processing. Based on a controlled interplay between dispersion and phase-modulation by e.g. four-wave mixing, the processing is phase-preserving, an hence useful for all types of data signals including coherent multi...

  8. Second-hand signals

    DEFF Research Database (Denmark)

    Bergenholtz, Carsten

    2014-01-01

    of signal of firms, which is based on a formalized common practice of external, academic experts referring to firms in their peer reviewed publications. The findings provide qualitative evidence that helps explain why and how this new type of ‘second‐hand’ signal is created, validated and systematically...

  9. SignalR blueprints

    CERN Document Server

    Ingebrigtsen, Einar

    2015-01-01

    This book is designed for software developers, primarily those with knowledge of C#, .NET, and JavaScript. Good knowledge and understanding of SignalR is assumed to allow efficient programming of core elements and applications in SignalR.

  10. Molecular and Cellular Signaling

    CERN Document Server

    Beckerman, Martin

    2005-01-01

    A small number of signaling pathways, no more than a dozen or so, form a control layer that is responsible for all signaling in and between cells of the human body. The signaling proteins belonging to the control layer determine what kinds of cells are made during development and how they function during adult life. Malfunctions in the proteins belonging to the control layer are responsible for a host of human diseases ranging from neurological disorders to cancers. Most drugs target components in the control layer, and difficulties in drug design are intimately related to the architecture of the control layer. Molecular and Cellular Signaling provides an introduction to molecular and cellular signaling in biological systems with an emphasis on the underlying physical principles. The text is aimed at upper-level undergraduates, graduate students and individuals in medicine and pharmacology interested in broadening their understanding of how cells regulate and coordinate their core activities and how diseases ...

  11. Calcium signaling and epilepsy.

    Science.gov (United States)

    Steinlein, Ortrud K

    2014-08-01

    Calcium signaling is involved in a multitude of physiological and pathophysiological mechanisms. Over the last decade, it has been increasingly recognized as an important factor in epileptogenesis, and it is becoming obvious that the excess synchronization of neurons that is characteristic for seizures can be linked to various calcium signaling pathways. These include immediate effects on membrane excitability by calcium influx through ion channels as well as delayed mechanisms that act through G-protein coupled pathways. Calcium signaling is able to cause hyperexcitability either by direct modulation of neuronal activity or indirectly through calcium-dependent gliotransmission. Furthermore, feedback mechanisms between mitochondrial calcium signaling and reactive oxygen species are able to cause neuronal cell death and seizures. Unravelling the complexity of calcium signaling in epileptogenesis is a daunting task, but it includes the promise to uncover formerly unknown targets for the development of new antiepileptic drugs.

  12. Acoustic Signals and Systems

    DEFF Research Database (Denmark)

    2008-01-01

    The Handbook of Signal Processing in Acoustics will compile the techniques and applications of signal processing as they are used in the many varied areas of Acoustics. The Handbook will emphasize the interdisciplinary nature of signal processing in acoustics. Each Section of the Handbook...... will present topics on signal processing which are important in a specific area of acoustics. These will be of interest to specialists in these areas because they will be presented from their technical perspective, rather than a generic engineering approach to signal processing. Non-specialists, or specialists...... from different areas, will find the self-contained chapters accessible and will be interested in the similarities and differences between the approaches and techniques used in different areas of acoustics....

  13. Exosomes in developmental signalling.

    Science.gov (United States)

    McGough, Ian John; Vincent, Jean-Paul

    2016-07-15

    In order to achieve coordinated growth and patterning during development, cells must communicate with one another, sending and receiving signals that regulate their activities. Such developmental signals can be soluble, bound to the extracellular matrix, or tethered to the surface of adjacent cells. Cells can also signal by releasing exosomes - extracellular vesicles containing bioactive molecules such as RNA, DNA and enzymes. Recent work has suggested that exosomes can also carry signalling proteins, including ligands of the Notch receptor and secreted proteins of the Hedgehog and WNT families. Here, we describe the various types of exosomes and their biogenesis. We then survey the experimental strategies used so far to interfere with exosome formation and critically assess the role of exosomes in developmental signalling. PMID:27436038

  14. Neutron signal transfer analysis

    CERN Document Server

    Pleinert, H; Lehmann, E

    1999-01-01

    A new method called neutron signal transfer analysis has been developed for quantitative determination of hydrogenous distributions from neutron radiographic measurements. The technique is based on a model which describes the detector signal obtained in the measurement as a result of the action of three different mechanisms expressed by signal transfer functions. The explicit forms of the signal transfer functions are determined by Monte Carlo computer simulations and contain only the distribution as a variable. Therefore an unknown distribution can be determined from the detector signal by recursive iteration. This technique provides a simple and efficient tool for analysis of this type while also taking into account complex effects due to the energy dependency of neutron interaction and single and multiple scattering. Therefore this method provides an efficient tool for precise quantitative analysis using neutron radiography, as for example quantitative determination of moisture distributions in porous buil...

  15. Biological signals as handicaps.

    Science.gov (United States)

    Grafen, A

    1990-06-21

    An ESS model of Zahavi's handicap principle is constructed. This allows a formal exposition of how the handicap principle works, and shows that its essential elements are strategic. The handicap model is about signalling, and it is proved under fairly general conditions that if the handicap principle's conditions are met, then an evolutionarily stable signalling equilibrium exists in a biological signalling system, and that any signalling equilibrium satisfies the conditions of the handicap principle. Zahavi's major claims for the handicap principle are thus vindicated. The place of cheating is discussed in view of the honesty that follows from the handicap principle. Parallel signalling models in economics are discussed. Interpretations of the handicap principle are compared. The models are not fully explicit about how females use information about male quality, and, less seriously, have no genetics. A companion paper remedies both defects in a model of the handicap principle at work in sexual selection. PMID:2402153

  16. Adaptive signal processor

    International Nuclear Information System (INIS)

    An experimental, general purpose adaptive signal processor system has been developed, utilizing a quantized (clipped) version of the Widrow-Hoff least-mean-square adaptive algorithm developed by Moschner. The system accommodates 64 adaptive weight channels with 8-bit resolution for each weight. Internal weight update arithmetic is performed with 16-bit resolution, and the system error signal is measured with 12-bit resolution. An adapt cycle of adjusting all 64 weight channels is accomplished in 8 μsec. Hardware of the signal processor utilizes primarily Schottky-TTL type integrated circuits. A prototype system with 24 weight channels has been constructed and tested. This report presents details of the system design and describes basic experiments performed with the prototype signal processor. Finally some system configurations and applications for this adaptive signal processor are discussed

  17. Signal sampling circuit

    OpenAIRE

    Louwsma, Simon Minze; Vertregt, Maarten

    2011-01-01

    A sampling circuit for sampling a signal is disclosed. The sampling circuit comprises a plurality of sampling channels adapted to sample the signal in time-multiplexed fashion, each sampling channel comprising a respective track-and-hold circuit connected to a respective analogue to digital converter via a respective output switch. The output switch of each channel opens for a tracking time period when the track-and-hold circuit is in a tracking mode for sampling the signal, and closes for a ...

  18. Signal flow analysis

    CERN Document Server

    Abrahams, J R; Hiller, N

    1965-01-01

    Signal Flow Analysis provides information pertinent to the fundamental aspects of signal flow analysis. This book discusses the basic theory of signal flow graphs and shows their relation to the usual algebraic equations.Organized into seven chapters, this book begins with an overview of properties of a flow graph. This text then demonstrates how flow graphs can be applied to a wide range of electrical circuits that do not involve amplification. Other chapters deal with the parameters as well as circuit applications of transistors. This book discusses as well the variety of circuits using ther

  19. Hedgehog signaling and steroidogenesis.

    Science.gov (United States)

    Finco, Isabella; LaPensee, Christopher R; Krill, Kenneth T; Hammer, Gary D

    2015-01-01

    Since its discovery nearly 30 years ago, the Hedgehog (Hh) signaling pathway has been shown to be pivotal in many developmental and pathophysiological processes in several steroidogenic tissues, including the testis, ovary, adrenal cortex, and placenta. New evidence links the evolutionarily conserved Hh pathway to the steroidogenic organs, demonstrating how Hh signaling can influence their development and homeostasis and can act in concert with steroids to mediate physiological functions. In this review, we highlight the role of the components of the Hh signaling pathway in steroidogenesis of endocrine tissues. PMID:25668018

  20. Signaling in muscle contraction.

    Science.gov (United States)

    Kuo, Ivana Y; Ehrlich, Barbara E

    2015-02-02

    Signaling pathways regulate contraction of striated (skeletal and cardiac) and smooth muscle. Although these are similar, there are striking differences in the pathways that can be attributed to the distinct functional roles of the different muscle types. Muscles contract in response to depolarization, activation of G-protein-coupled receptors and other stimuli. The actomyosin fibers responsible for contraction require an increase in the cytosolic levels of calcium, which signaling pathways induce by promoting influx from extracellular sources or release from intracellular stores. Rises in cytosolic calcium stimulate numerous downstream calcium-dependent signaling pathways, which can also regulate contraction. Alterations to the signaling pathways that initiate and sustain contraction and relaxation occur as a consequence of exercise and pathophysiological conditions.

  1. Error-prone signalling.

    Science.gov (United States)

    Johnstone, R A; Grafen, A

    1992-06-22

    The handicap principle of Zahavi is potentially of great importance to the study of biological communication. Existing models of the handicap principle, however, make the unrealistic assumption that communication is error free. It seems possible, therefore, that Zahavi's arguments do not apply to real signalling systems, in which some degree of error is inevitable. Here, we present a general evolutionarily stable strategy (ESS) model of the handicap principle which incorporates perceptual error. We show that, for a wide range of error functions, error-prone signalling systems must be honest at equilibrium. Perceptual error is thus unlikely to threaten the validity of the handicap principle. Our model represents a step towards greater realism, and also opens up new possibilities for biological signalling theory. Concurrent displays, direct perception of quality, and the evolution of 'amplifiers' and 'attenuators' are all probable features of real signalling systems, yet handicap models based on the assumption of error-free communication cannot accommodate these possibilities. PMID:1354361

  2. Signals from the Cosmos.

    Science.gov (United States)

    Lichtman, Jeffrey M.

    1991-01-01

    Introduces the basics of radio astronomy and describes how to assemble several simple systems for receiving radio signals from the cosmos. Includes schematics, parts lists, working drawings, and contact information for radio astronomy suppliers. (11 references) (Author/JJK)

  3. Foundations of signal processing

    CERN Document Server

    Vetterli, Martin; Goyal, Vivek K

    2014-01-01

    This comprehensive and engaging textbook introduces the basic principles and techniques of signal processing, from the fundamental ideas of signals and systems theory to real-world applications. Students are introduced to the powerful foundations of modern signal processing, including the basic geometry of Hilbert space, the mathematics of Fourier transforms, and essentials of sampling, interpolation, approximation and compression. The authors discuss real-world issues and hurdles to using these tools, and ways of adapting them to overcome problems of finiteness and localisation, the limitations of uncertainty and computational costs. Standard engineering notation is used throughout, making mathematical examples easy for students to follow, understand and apply. It includes over 150 homework problems and over 180 worked examples, specifically designed to test and expand students' understanding of the fundamentals of signal processing, and is accompanied by extensive online materials designed to aid learning, ...

  4. Topological signal processing

    CERN Document Server

    Robinson, Michael

    2014-01-01

    Signal processing is the discipline of extracting information from collections of measurements. To be effective, the measurements must be organized and then filtered, detected, or transformed to expose the desired information.  Distortions caused by uncertainty, noise, and clutter degrade the performance of practical signal processing systems. In aggressively uncertain situations, the full truth about an underlying signal cannot be known.  This book develops the theory and practice of signal processing systems for these situations that extract useful, qualitative information using the mathematics of topology -- the study of spaces under continuous transformations.  Since the collection of continuous transformations is large and varied, tools which are topologically-motivated are automatically insensitive to substantial distortion. The target audience comprises practitioners as well as researchers, but the book may also be beneficial for graduate students.

  5. Modularity in signaling systems

    International Nuclear Information System (INIS)

    Modularity is a property by which the behavior of a system does not change upon interconnection. It is crucial for understanding the behavior of a complex system from the behavior of the composing subsystems. Whether modularity holds in biology is an intriguing and largely debated question. In this paper, we discuss this question taking a control system theory view and focusing on signaling systems. In particular, we argue that, despite signaling systems being constituted of structural modules, such as covalent modification cycles, modularity does not hold in general. As in any engineering system, impedance-like effects, called retroactivity, appear at interconnections and alter the behavior of connected modules. We further argue that while signaling systems have evolved sophisticated ways to counter-act retroactivity and enforce modularity, retroactivity may also be exploited to finely control the information processing of signaling pathways. Testable predictions and experimental evidence are discussed with their implications. (paper)

  6. Signal-light nomogram

    Science.gov (United States)

    Gordon, J. I.; Edgerton, C. F.; Duntley, S. Q.

    1975-01-01

    A nomogram is presented for predicting the sighting range for white, steady-burning signal lights. The theoretical and experimental bases are explained and instructions are provided for its use for a variety of practical problems concerning the visibility of signal lights. The nomogram is appropriate for slant path as well as horizontal sightings, and the gain of range achieved by utilizing binoculars can be predicted by use of it.

  7. Digital signal processing: Handbook

    Science.gov (United States)

    Goldenberg, L. M.; Matiushkin, B. D.; Poliak, M. N.

    The fundamentals of the theory and design of systems and devices for the digital processing of signals are presented. Particular attention is given to algorithmic methods of synthesis and digital processing equipment in communication systems (e.g., selective digital filtering, spectral analysis, and variation of the signal discretization frequency). Programs for the computer-aided analysis of digital filters are described. Computational examples are presented, along with tables of transfer function coefficients for recursive and nonrecursive digital filters.

  8. Modest Advertising Signals Strength.

    OpenAIRE

    Ram Orzach; Per Baltzer Overgaard; Yair Tauman

    2001-01-01

    This paper presents a signaling model where both price and advertising expenditures are used as signals of the initially unobservable quality of a newly introduced experience good. Consumers can be either "fastidious" or "indifferent". Fastidious individuals place a greater value on a high-quality product and a lesser value on the low-quality product than do indifferent individuals. It is shown that a sensible separating equilibrium exists where both firms set their full information prices. H...

  9. Updating dopamine reward signals

    OpenAIRE

    Schultz, Wolfram

    2013-01-01

    Recent work has advanced our knowledge of phasic dopamine reward prediction error signals. The error signal is bidirectional, reflects well the higher order prediction error described by temporal difference learning models, is compatible with model-free and model-based reinforcement learning, reports the subjective rather than physical reward value during temporal discounting and reflects subjective stimulus perception rather than physical stimulus aspects. Dopamine activations are primarily ...

  10. Ultrahigh bandwidth signal processing

    Science.gov (United States)

    Oxenløwe, Leif Katsuo

    2016-04-01

    Optical time lenses have proven to be very versatile for advanced optical signal processing. Based on a controlled interplay between dispersion and phase-modulation by e.g. four-wave mixing, the processing is phase-preserving, and hence useful for all types of data signals including coherent multi-level modulation formats. This has enabled processing of phase-modulated spectrally efficient data signals, such as orthogonal frequency division multiplexed (OFDM) signals. In that case, a spectral telescope system was used, using two time lenses with different focal lengths (chirp rates), yielding a spectral magnification of the OFDM signal. Utilising such telescopic arrangements, it has become possible to perform a number of interesting functionalities, which will be described in the presentation. This includes conversion from OFDM to Nyquist WDM, compression of WDM channels to a single Nyquist channel and WDM regeneration. These operations require a broad bandwidth nonlinear platform, and novel photonic integrated nonlinear platforms like aluminum gallium arsenide nano-waveguides used for 1.28 Tbaud optical signal processing will be described.

  11. Wnt Signaling in Bone

    Science.gov (United States)

    Kubota, Takuo; Michigami, Toshimi; Ozono, Keiichi

    2010-01-01

    Wnt signaling is involved not only in embryonic development but also in maintenance of homeostasis in postnatal tissues. Multiple lines of evidence have increased understanding of the roles of Wnt signaling in bone since mutations in the LRP5 gene were identified in human bone diseases. Canonical Wnt signaling promotes mesenchymal progenitor cells to differentiate into osteoblasts. The canonical Wnt/β-catenin pathway possibly through Lrp6, a co-receptor for Wnts as well as Lrp5, in osteoblasts regulates bone resorption by increasing the OPG/RANKL ratio. However, endogenous inhibitors of Wnt signaling including sclerostin block bone formation. Regulation of sclerostin appears to be one of the mechanisms of PTH anabolic actions on bone. Since sclerostin is almost exclusively expressed in osteocytes, inhibition of sclerostin is the most promising design. Surprisingly, Lrp5 controls bone formation by inhibiting serotonin synthesis in the duodenum, but not by directly promoting bone formation. Pharmacological intervention may be considered in many components of the canonical Wnt signaling pathway, although adverse effects and tumorigenicity to other tissues are important. More studies will be needed to fully understand how the Wnt signaling pathway actually influences bone metabolism and to assure the safety of new interventions. PMID:23926379

  12. Digital Signal Processing applied to Physical Signals

    CERN Document Server

    Alberto, Diego; Musa, L

    2011-01-01

    It is well known that many of the scientific and technological discoveries of the XXI century will depend on the capability of processing and understanding a huge quantity of data. With the advent of the digital era, a fully digital and automated treatment can be designed and performed. From data mining to data compression, from signal elaboration to noise reduction, a processing is essential to manage and enhance features of interest after every data acquisition (DAQ) session. In the near future, science will go towards interdisciplinary research. In this work there will be given an example of the application of signal processing to different fields of Physics from nuclear particle detectors to biomedical examinations. In Chapter 1 a brief description of the collaborations that allowed this thesis is given, together with a list of the publications co-produced by the author in these three years. The most important notations, definitions and acronyms used in the work are also provided. In Chapter 2, the last r...

  13. Vibrio vulnificus VvhA induces autophagy-related cell death through the lipid raft-dependent c-Src/NOX signaling pathway.

    Science.gov (United States)

    Song, Eun Ju; Lee, Sei-Jung; Lim, Hyeon Su; Kim, Jun Sung; Jang, Kyung Ku; Choi, Sang Ho; Han, Ho Jae

    2016-06-02

    VvhA, a virulent factor of Vibrio (V.) vulnificus, induces acute cell death in a destructive manner. Autophagy plays an important role in cell death, but the functional role of VvhA in autophagy-related cell death has not been elucidated yet. We found that rVvhA significantly increased LC3 puncta formation and autophagic flux in promoting the cell death of human intestinal epithelial Caco-2 cells. The cell death induced by rVvhA was independent of lysosomal permeabilizaton and caspase activation. rVvhA induced rapid phosphorylation of c-Src in the membrane lipid raft, which resulted in an increased interaction between lipid raft molecule caveolin-1 and NADPH oxidase (NOX) complex Rac1 for ROS production. NOX-mediated ROS signaling induced by rVvhA increased the phosphorylation of extracellular signal-regulated kinase (ERK) and eukaryotic translation initiation factor 2α (eIF2α) which are required for mRNA expression of Atg5 and Atg16L1 involved in autophagosome formation. In an in vivo model, VvhA increased autophagy activation and paracellular permeabilization in intestinal epithelium. Collectively, the results here show that VvhA plays a pivotal role in the pathogenesis and dissemination of V. vulnificus by autophagy upregulation, through the lipid raft-mediated c-Src/NOX signaling pathway and ERK/eIF2α activation.

  14. Vibrio vulnificus VvhA induces autophagy-related cell death through the lipid raft-dependent c-Src/NOX signaling pathway

    Science.gov (United States)

    Song, Eun Ju; Lee, Sei-Jung; Lim, Hyeon Su; Kim, Jun Sung; Jang, Kyung Ku; Choi, Sang Ho; Han, Ho Jae

    2016-01-01

    VvhA, a virulent factor of Vibrio (V.) vulnificus, induces acute cell death in a destructive manner. Autophagy plays an important role in cell death, but the functional role of VvhA in autophagy-related cell death has not been elucidated yet. We found that rVvhA significantly increased LC3 puncta formation and autophagic flux in promoting the cell death of human intestinal epithelial Caco-2 cells. The cell death induced by rVvhA was independent of lysosomal permeabilizaton and caspase activation. rVvhA induced rapid phosphorylation of c-Src in the membrane lipid raft, which resulted in an increased interaction between lipid raft molecule caveolin-1 and NADPH oxidase (NOX) complex Rac1 for ROS production. NOX-mediated ROS signaling induced by rVvhA increased the phosphorylation of extracellular signal-regulated kinase (ERK) and eukaryotic translation initiation factor 2α (eIF2α) which are required for mRNA expression of Atg5 and Atg16L1 involved in autophagosome formation. In an in vivo model, VvhA increased autophagy activation and paracellular permeabilization in intestinal epithelium. Collectively, the results here show that VvhA plays a pivotal role in the pathogenesis and dissemination of V. vulnificus by autophagy upregulation, through the lipid raft-mediated c-Src/NOX signaling pathway and ERK/eIF2α activation. PMID:27250250

  15. A stilbene synthase allele from a Chinese wild grapevine confers resistance to powdery mildew by recruiting salicylic acid signalling for efficient defence

    Science.gov (United States)

    Jiao, Yuntong; Xu, Weirong; Duan, Dong; Wang, Yuejin; Nick, Peter

    2016-01-01

    Stilbenes are central phytoalexins in Vitis, and induction of the key enzyme stilbene synthase (STS) is pivotal for disease resistance. Here, we address the potential for breeding resistance using an STS allele isolated from Chinese wild grapevine Vitis pseudoreticulata (VpSTS) by comparison with its homologue from Vitis vinifera cv. ‘Carigane’ (VvSTS). Although the coding regions of both alleles are very similar (>99% identity on the amino acid level), the promoter regions are significantly different. By expression in Arabidopsis as a heterologous system, we show that the allele from the wild Chinese grapevine can confer accumulation of stilbenes and resistance against the powdery mildew Golovinomyces cichoracearum, whereas the allele from the vinifera cultivar cannot. To dissect the upstream signalling driving the activation of this promoter, we used a dual-luciferase reporter system in a grapevine cell culture. We show elevated responsiveness of the promoter from the wild grape to salicylic acid (SA) and to the pathogen-associated molecular pattern (PAMP) flg22, equal induction of both alleles by jasmonic acid (JA), and a lack of response to the cell death-inducing elicitor Harpin. This elevated SA response of the VpSTS promoter depends on calcium influx, oxidative burst by RboH, mitogen-activated protein kinase (MAPK) signalling, and JA synthesis. We integrate the data in the context of a model where the resistance of V. pseudoreticulata is linked to a more efficient recruitment of SA signalling for phytoalexin synthesis. PMID:27702992

  16. VLSI signal processing technology

    CERN Document Server

    Swartzlander, Earl

    1994-01-01

    This book is the first in a set of forthcoming books focussed on state-of-the-art development in the VLSI Signal Processing area. It is a response to the tremendous research activities taking place in that field. These activities have been driven by two factors: the dramatic increase in demand for high speed signal processing, especially in consumer elec­ tronics, and the evolving microelectronic technologies. The available technology has always been one of the main factors in determining al­ gorithms, architectures, and design strategies to be followed. With every new technology, signal processing systems go through many changes in concepts, design methods, and implementation. The goal of this book is to introduce the reader to the main features of VLSI Signal Processing and the ongoing developments in this area. The focus of this book is on: • Current developments in Digital Signal Processing (DSP) pro­ cessors and architectures - several examples and case studies of existing DSP chips are discussed in...

  17. Signaling cascades modulate the speed of signal propagation through space.

    Directory of Open Access Journals (Sweden)

    Christopher C Govern

    Full Text Available BACKGROUND: Cells are not mixed bags of signaling molecules. As a consequence, signals must travel from their origin to distal locations. Much is understood about the purely diffusive propagation of signals through space. Many signals, however, propagate via signaling cascades. Here, we show that, depending on their kinetics, cascades speed up or slow down the propagation of signals through space, relative to pure diffusion. METHODOLOGY/PRINCIPAL FINDINGS: We modeled simple cascades operating under different limits of Michaelis-Menten kinetics using deterministic reaction-diffusion equations. Cascades operating far from enzyme saturation speed up signal propagation; the second mobile species moves more quickly than the first through space, on average. The enhanced speed is due to more efficient serial activation of a downstream signaling module (by the signaling molecule immediately upstream in the cascade at points distal from the signaling origin, compared to locations closer to the source. Conversely, cascades operating under saturated kinetics, which exhibit zero-order ultrasensitivity, can slow down signals, ultimately localizing them to regions around the origin. CONCLUSIONS/SIGNIFICANCE: Signal speed modulation may be a fundamental function of cascades, affecting the ability of signals to penetrate within a cell, to cross-react with other signals, and to activate distant targets. In particular, enhanced speeds provide a way to increase signal penetration into a cell without needing to flood the cell with large numbers of active signaling molecules; conversely, diminished speeds in zero-order ultrasensitive cascades facilitate strong, but localized, signaling.

  18. Signal integrity characterization techniques

    CERN Document Server

    Bogatin, Eric

    2009-01-01

    "Signal Integrity Characterization Techniques" addresses the gap between traditional digital and microwave curricula all while focusing on a practical and intuitive understanding of signal integrity effects within the data transmission channel. High-speed interconnects such as connectors, PCBs, cables, IC packages, and backplanes are critical elements of differential channels that must be designed using today's most powerful analysis and characterization tools.Both measurements and simulation must be done on the device under test, and both activities must yield data that correlates with each other. Most of this book focuses on real-world applications of signal integrity measurements - from backplane for design challenges to error correction techniques to jitter measurement technologies. The authors' approach wisely addresses some of these new high-speed technologies, and it also provides valuable insight into its future direction and will teach the reader valuable lessons on the industry.

  19. Telemetry Ranging: Signal Processing

    Science.gov (United States)

    Hamkins, J.; Kinman, P.; Xie, H.; Vilnrotter, V.; Dolinar, S.

    2016-02-01

    This article describes the details of the signal processing used in a telemetry ranging system in which timing information is extracted from the downlink telemetry signal in order to compute spacecraft range. A previous article describes telemetry ranging concepts and architecture, which are a slight variation of a scheme published earlier. As in that earlier work, the telemetry ranging concept eliminates the need for a dedicated downlink ranging signal to communicate the necessary timing information. The present article describes the operation and performance of the major receiver functions on the spacecraft and the ground --- many of which are standard tracking loops already in use in JPL's flight and ground radios --- and how they can be used to provide the relevant information for making a range measurement. It also describes the implementation of these functions in software, and performance of an end-to-end software simulation of the telemetry ranging system.

  20. Purinergic signalling and diabetes

    DEFF Research Database (Denmark)

    Burnstock, Geoffrey; Novak, Ivana

    2013-01-01

    The pancreas is an organ with a central role in nutrient breakdown, nutrient sensing and release of hormones regulating whole body nutrient homeostasis. In diabetes mellitus, the balance is broken-cells can be starving in the midst of plenty. There are indications that the incidence of diabetes...... type 1 and 2, and possibly pancreatogenic diabetes, is rising globally. Events leading to insulin secretion and action are complex, but there is emerging evidence that intracellular nucleotides and nucleotides are not only important as intracellular energy molecules but also as extracellular signalling...... molecules in purinergic signalling cascades. This signalling takes place at the level of the pancreas, where the close apposition of various cells-endocrine, exocrine, stromal and immune cells-contributes to the integrated function. Following an introduction to diabetes, the pancreas and purinergic...

  1. Updating dopamine reward signals.

    Science.gov (United States)

    Schultz, Wolfram

    2013-04-01

    Recent work has advanced our knowledge of phasic dopamine reward prediction error signals. The error signal is bidirectional, reflects well the higher order prediction error described by temporal difference learning models, is compatible with model-free and model-based reinforcement learning, reports the subjective rather than physical reward value during temporal discounting and reflects subjective stimulus perception rather than physical stimulus aspects. Dopamine activations are primarily driven by reward, and to some extent risk, whereas punishment and salience have only limited activating effects when appropriate controls are respected. The signal is homogeneous in terms of time course but heterogeneous in many other aspects. It is essential for synaptic plasticity and a range of behavioural learning situations.

  2. Genomic signal processing

    CERN Document Server

    Shmulevich, Ilya

    2007-01-01

    Genomic signal processing (GSP) can be defined as the analysis, processing, and use of genomic signals to gain biological knowledge, and the translation of that knowledge into systems-based applications that can be used to diagnose and treat genetic diseases. Situated at the crossroads of engineering, biology, mathematics, statistics, and computer science, GSP requires the development of both nonlinear dynamical models that adequately represent genomic regulation, and diagnostic and therapeutic tools based on these models. This book facilitates these developments by providing rigorous mathema

  3. TOR signalling in plants.

    Science.gov (United States)

    Rexin, Daniel; Meyer, Christian; Robaglia, Christophe; Veit, Bruce

    2015-08-15

    Although the eukaryotic TOR (target of rapamycin) kinase signalling pathway has emerged as a key player for integrating nutrient-, energy- and stress-related cues with growth and metabolic outputs, relatively little is known of how this ancient regulatory mechanism has been adapted in higher plants. Drawing comparisons with the substantial knowledge base around TOR kinase signalling in fungal and animal systems, functional aspects of this pathway in plants are reviewed. Both conserved and divergent elements are discussed in relation to unique aspects associated with an autotrophic mode of nutrition and adaptive strategies for multicellular development exhibited by plants.

  4. Understanding signal integrity

    CERN Document Server

    Thierauf, Stephen C

    2010-01-01

    This unique book provides you with practical guidance on understanding and interpreting signal integrity (SI) performance to help you with your challenging circuit board design projects. You find high-level discussions of important SI concepts presented in a clear and easily accessible format, including question and answer sections and bulleted lists.This valuable resource features rules of thumb and simple equations to help you make estimates of critical signal integrity parameters without using circuit simulators of CAD (computer-aided design). The book is supported with over 120 illustratio

  5. Electronic signal conditioning

    CERN Document Server

    NEWBY, BRUCE

    1994-01-01

    At technician level, brief references to signal conditioning crop up in a fragmented way in various textbooks, but there has been no single textbook, until now!More advanced texts do exist but they are more mathematical and presuppose a higher level of understanding of electronics and statistics. Electronic Signal Conditioning is designed for HNC/D students and City & Guilds Electronics Servicing 2240 Parts 2 & 3. It will also be useful for BTEC National, Advanced GNVQ, A-level electronics and introductory courses at degree level.

  6. Mechanisms of auxin signaling.

    Science.gov (United States)

    Lavy, Meirav; Estelle, Mark

    2016-09-15

    The plant hormone auxin triggers complex growth and developmental processes. Its underlying molecular mechanism of action facilitates rapid switching between transcriptional repression and gene activation through the auxin-dependent degradation of transcriptional repressors. The nuclear auxin signaling pathway consists of a small number of core components. However, in most plants each component is represented by a large gene family. The modular construction of the pathway can thus produce diverse transcriptional outputs depending on the cellular and environmental context. Here, and in the accompanying poster, we outline the current model for TIR1/AFB-dependent auxin signaling with an emphasis on recent studies. PMID:27624827

  7. Hybrid ECG signal conditioner

    Science.gov (United States)

    Rinard, G. A.; Steffen, D. A.; Sturm, R. E.

    1979-01-01

    Circuit with high common-mode rejection has ability to filter and amplify accepted analog electrocardiogram (ECG) signals of varying amplitude, shape, and polarity. In addition, low power circuit develops standardized pulses that can be counted and averaged by heart/breath rate processor.

  8. Mediation as Signal

    NARCIS (Netherlands)

    Holler, M.J.; Lindner, I.

    2004-01-01

    This paper analyzes mediation as a signal. Starting from a stylized case, a game theoretical model of one-sided incomplete information, taken from Cho and Kreps (1987), is applied to discuss strategic effects of mediation. It turns out that to reject mediation can be interpreted as a ”negative signa

  9. Targeting Hedgehog signaling pathway and autophagy overcomes drug resistance of BCR-ABL-positive chronic myeloid leukemia.

    Science.gov (United States)

    Zeng, Xian; Zhao, Hui; Li, Yubin; Fan, Jiajun; Sun, Yun; Wang, Shaofei; Wang, Ziyu; Song, Ping; Ju, Dianwen

    2015-01-01

    The frontline tyrosine kinase inhibitor (TKI) imatinib has revolutionized the treatment of patients with chronic myeloid leukemia (CML). However, drug resistance is the major clinical challenge in the treatment of CML. The Hedgehog (Hh) signaling pathway and autophagy are both related to tumorigenesis, cancer therapy, and drug resistance. This study was conducted to explore whether the Hh pathway could regulate autophagy in CML cells and whether simultaneously regulating the Hh pathway and autophagy could induce cell death of drug-sensitive or -resistant BCR-ABL(+) CML cells. Our results indicated that pharmacological or genetic inhibition of Hh pathway could markedly induce autophagy in BCR-ABL(+) CML cells. Autophagic inhibitors or ATG5 and ATG7 silencing could significantly enhance CML cell death induced by Hh pathway suppression. Based on the above findings, our study demonstrated that simultaneously inhibiting the Hh pathway and autophagy could markedly reduce cell viability and induce apoptosis of imatinib-sensitive or -resistant BCR-ABL(+) cells. Moreover, this combination had little cytotoxicity in human peripheral blood mononuclear cells (PBMCs). Furthermore, this combined strategy was related to PARP cleavage, CASP3 and CASP9 cleavage, and inhibition of the BCR-ABL oncoprotein. In conclusion, this study indicated that simultaneously inhibiting the Hh pathway and autophagy could potently kill imatinib-sensitive or -resistant BCR-ABL(+) cells, providing a novel concept that simultaneously inhibiting the Hh pathway and autophagy might be a potent new strategy to overcome CML drug resistance.

  10. Wnt signaling in osteosarcoma.

    Science.gov (United States)

    Lin, Carol H; Ji, Tao; Chen, Cheng-Fong; Hoang, Bang H

    2014-01-01

    Osteosarcoma (OS) is the most common primary bone malignancy diagnosed in children and adolescents with a high propensity for local invasion and distant metastasis. Despite current multidisciplinary treatments, there has not been a drastic change in overall prognosis within the last two decades. With current treatments, 60-70 % of patients with localized disease survive. Given a propensity of Wnt signaling to control multiple cellular processes, including proliferation, cell fate determination, and differentiation, it is a critical pathway in OS disease progression. At the same time, this pathway is extremely complex with vast arrays of cross-talk. Even though decades of research have linked the role of Wnt to tumorigenesis, there are still outstanding areas that remain poorly understood and even controversial. The canonical Wnt pathway functions to regulate the levels of the transcriptional co-activator β-catenin, which ultimately controls key developmental gene expressions. Given the central role of this mediator, inhibition of Wnt/β-catenin signaling has been investigated as a potential strategy for cancer control. In OS, several secreted protein families modulate the Wnt/β-catenin signaling, including secreted Frizzled-related proteins (sFRPs), Wnt inhibitory protein (WIF), Dickkopf proteins (DKK-1,2,3), sclerostin, and small molecules. This chapter focuses on our current understanding of Wnt/β-catenin signaling in OS, based on recent in vitro and in vivo data. Wnt activates noncanonical signaling pathways as well that are independent of β-catenin which will be discussed. In addition, stem cells and their association with Wnt/β-catenin are important factors to consider. Ultimately, the multiple canonical and noncanonical Wnt/β-catenin agonists and antagonists need to be further explored for potential targeted therapies. PMID:24924167

  11. Small Turing universal signal machines

    Directory of Open Access Journals (Sweden)

    Jérôme Durand-Lose

    2009-06-01

    Full Text Available This article aims at providing signal machines as small as possible able to perform any computation (in the classical understanding. After presenting signal machines, it is shown how to get universal ones from Turing machines, cellular-automata and cyclic tag systems. Finally a halting universal signal machine with 13 meta-signals and 21 collision rules is presented.

  12. Analog and digital signal processing

    Science.gov (United States)

    Baher, H.

    The techniques of signal processing in both the analog and digital domains are addressed in a fashion suitable for undergraduate courses in modern electrical engineering. The topics considered include: spectral analysis of continuous and discrete signals, analysis of continuous and discrete systems and networks using transform methods, design of analog and digital filters, digitization of analog signals, power spectrum estimation of stochastic signals, FFT algorithms, finite word-length effects in digital signal processes, linear estimation, and adaptive filtering.

  13. Education - A Job Market Signal?

    OpenAIRE

    Leino, Topias

    2008-01-01

    This paper reviews the theoretical and empirical literature on job market signalling and on education as a job market signal. Possible economic implications of educational job market signalling to an individual and the society are represented based on existing theories. The paper also reviews central methods in empirical testing of the signalling/screening hypothesis. The empirical section of the paper carries out two alternative methods for testing the signalling/sorting hypothesis. The firs...

  14. Biomedical signal analysis

    CERN Document Server

    Rangayyan, Rangaraj M

    2015-01-01

    The book will help assist a reader in the development of techniques for analysis of biomedical signals and computer aided diagnoses with a pedagogical examination of basic and advanced topics accompanied by over 350 figures and illustrations. Wide range of filtering techniques presented to address various applications. 800 mathematical expressions and equations. Practical questions, problems and laboratory exercises. Includes fractals and chaos theory with biomedical applications.

  15. Plant signalling peptides

    OpenAIRE

    Wiśniewska, Justyna; Trejgell, Alina; Tretyn, Andrzej

    2003-01-01

    Biochemical and genetic studies have identified peptides that play crucial roles in plant growth and development, including defence mechanisms in response to wounding by pests, the control of cell division and expansion, and pollen self-incompatibility. The first two signalling peptides to be described in plants were tomato systemin and phytosulfokine (PSK). There is also biochemical evidence that natriuretic peptide-like molecules, immunologically-relatedt o those found ...

  16. Insulin signaling and addiction

    OpenAIRE

    Lynette C Daws; Avison, Malcolm J.; Robertson, Sabrina D.; Niswender, Kevin D.; Galli, Aurelio; Saunders, Christine

    2011-01-01

    Across species, the brain evolved to respond to natural rewards such as food and sex. These physiological responses are important for survival, reproduction and evolutionary processes. It is no surprise, therefore, that many of the neural circuits and signaling pathways supporting reward processes are conserved from Caenorhabditis elegans to Drosophilae, to rats, monkeys and humans. The central role of dopamine (DA) in encoding reward and in attaching salience to external environmental cues i...

  17. Mediation as Signal

    OpenAIRE

    Holler, M.J.; Lindner, I.

    2004-01-01

    This paper analyzes mediation as a signal. Starting from a stylized case, a game theoretical model of one-sided incomplete information, taken from Cho and Kreps (1987), is applied to discuss strategic effects of mediation. It turns out that to reject mediation can be interpreted as a ”negative signal” while the interpretation of accepting or proposing mediation is ambiguous and does not necessarily change the prior beliefs of the uninformed party. This asymmetry suggests that, in equilibrium,...

  18. Olfactory signaling in insects.

    Science.gov (United States)

    Wicher, Dieter

    2015-01-01

    The detection of volatile chemical information in insects is performed by three types of olfactory receptors, odorant receptors (ORs), specific gustatory receptor (GR) proteins for carbon dioxide perception, and ionotropic receptors (IRs) which are related to ionotropic glutamate receptors. All receptors form heteromeric assemblies; an OR complex is composed of an odor-specific OrX protein and a coreceptor (Orco). ORs and GRs have a 7-transmembrane topology as for G protein-coupled receptors, but they are inversely inserted into the membrane. Ligand-gated ion channels (ionotropic receptors) and ORs operate as IRs activated by volatile chemical cues. ORs are evolutionarily young receptors, and they first appear in winged insects and seem to be evolved to allow an insect to follow sparse odor tracks during flight. In contrast to IRs, the ORs can be sensitized by repeated subthreshold odor stimulation. This process involves metabotropic signaling. Pheromone receptors are especially sensitive and require an accessory protein to detect the lipid-derived pheromone molecules. Signaling cascades involved in pheromone detection depend on intensity and duration of stimuli and underlie a circadian control. Taken together, detection and processing of volatile information in insects involve ionotropic as well as metabotropic mechanisms. Here, I review the cellular signaling events associated with detection of cognate ligands by the different types of odorant receptors.

  19. The Signal Space Separation method

    CERN Document Server

    Taulu, S; Simola, J; Taulu, Samu; Kajola, Matti; Simola, Juha

    2004-01-01

    Multichannel measurement with hundreds of channels essentially covers all measurable degrees of freedom of a curl and source free vector field, like the magnetic field in a volume free of current sources (e.g. in magnetoencephalography, MEG). A functional expansion solution of Laplace's equation enables one to separate signals arising from the sphere enclosing the interesting sources, e.g. the currents in the brain, from the rest of the signals. The signal space separation (SSS) is accomplished by calculating individual basis vectors for each term of the functional expansion solution to create a signal basis covering all measurable signal vectors. Any signal vector has a unique SSS decomposition with separate coefficients for the interesting signals and signals coming from outside the interesting volume. Thus, SSS basis provides an elegant method to remove external disturbances, and to transform the interesting signals to virtual sensor configurations. SSS can also be used in compensating the movements of the...

  20. Uncertainty product of composite signals

    International Nuclear Information System (INIS)

    The well known uncertainty product of communication theory for a signal in the time domain and its Fourier transform in the frequency domain is studied for a 'composite signal', i.e. a 'pure' signal to which a time-delayed replica is added. This uncertainty product shows the appearance of local maxima and minima as a function of the time delay, leading to the following conjecture: the uncertainty product of a non-Gaussian composite signal can be smaller than that of the 'pure' signal. As an example this conjecture will be proven for the derivative of the Gaussian signal and for the Cauchy distribution. The effect on the uncertainty product of adding a delayed scaled replica of a signal to the original signal in the time domain leads to an important possibility for interpretation in the study of the reverberation phenomenon in echo-location signals of dolphins. (author). Letter-to-the-editor

  1. Biomedical signal and image processing

    CERN Document Server

    Najarian, Kayvan

    2012-01-01

    INTRODUCTION TO DIGITAL SIGNAL AND IMAGE PROCESSINGSignals and Biomedical Signal ProcessingIntroduction and OverviewWhat is a ""Signal""?Analog, Discrete, and Digital SignalsProcessing and Transformation of SignalsSignal Processing for Feature ExtractionSome Characteristics of Digital ImagesSummaryProblemsFourier TransformIntroduction and OverviewOne-Dimensional Continuous Fourier TransformSampling and NYQUIST RateOne-Dimensional Discrete Fourier TransformTwo-Dimensional Discrete Fourier TransformFilter DesignSummaryProblemsImage Filtering, Enhancement, and RestorationIntroduction and Overview

  2. Phonocardiography Signal Processing

    CERN Document Server

    Abbas, Abbas K

    2009-01-01

    The auscultation method is an important diagnostic indicator for hemodynamic anomalies. Heart sound classification and analysis play an important role in the auscultative diagnosis. The term phonocardiography refers to the tracing technique of heart sounds and the recording of cardiac acoustics vibration by means of a microphone-transducer. Therefore, understanding the nature and source of this signal is important to give us a tendency for developing a competent tool for further analysis and processing, in order to enhance and optimize cardiac clinical diagnostic approach. This book gives the

  3. Sphingosine signaling and atherogenesis

    DEFF Research Database (Denmark)

    Xu, Cang-bao; Hansen-Schwartz, Jacob; Edvinsson, Lars

    2004-01-01

    Sphingosine-1-phosphate (S1P) has diverse biological functions acting inside cells as a second messenger to regulate cell proliferation and survival, and extracellularly, as a ligand for a group of G protein-coupled receptors (GPCRs) named the endothelial differentiation gene (EDG) family. Five......+ mobilization, and expression of adhesion molecules. The formation of an atherosclerotic lesion occurs through activation of cellular events that include monocyte adhesion to the endothelium and vascular smooth muscle cell (VSMC) migration and proliferation. Thus, S1P signaling may play an important role...

  4. Multiscale Signal Analysis and Modeling

    CERN Document Server

    Zayed, Ahmed

    2013-01-01

    Multiscale Signal Analysis and Modeling presents recent advances in multiscale analysis and modeling using wavelets and other systems. This book also presents applications in digital signal processing using sampling theory and techniques from various function spaces, filter design, feature extraction and classification, signal and image representation/transmission, coding, nonparametric statistical signal processing, and statistical learning theory. This book also: Discusses recently developed signal modeling techniques, such as the multiscale method for complex time series modeling, multiscale positive density estimations, Bayesian Shrinkage Strategies, and algorithms for data adaptive statistics Introduces new sampling algorithms for multidimensional signal processing Provides comprehensive coverage of wavelets with presentations on waveform design and modeling, wavelet analysis of ECG signals and wavelet filters Reviews features extraction and classification algorithms for multiscale signal and image proce...

  5. Biological signals classification and analysis

    CERN Document Server

    Kiasaleh, Kamran

    2015-01-01

    This authored monograph presents key aspects of signal processing analysis in the biomedical arena. Unlike wireless communication systems, biological entities produce signals with underlying nonlinear, chaotic nature that elude classification using the standard signal processing techniques, which have been developed over the past several decades for dealing primarily with standard communication systems. This book separates what is random from that which appears to be random, and yet is truly deterministic with random appearance. At its core, this work gives the reader a perspective on biomedical signals and the means to classify and process such signals. In particular, a review of random processes along with means to assess the behavior of random signals is also provided. The book also includes a general discussion of biological signals in order to demonstrate the inefficacy of the well-known techniques to correctly extract meaningful information from such signals. Finally, a thorough discussion of recently ...

  6. Wireless data signal transmission system

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to a method for providing a radio frequency signal for transmission, a system for providing a radio frequency signal for transmission and a method for wireless data transmission between a transmitter and a receiver.......The present invention relates to a method for providing a radio frequency signal for transmission, a system for providing a radio frequency signal for transmission and a method for wireless data transmission between a transmitter and a receiver....

  7. Two-dimensional signal analysis

    CERN Document Server

    Garello, René

    2010-01-01

    This title sets out to show that 2-D signal analysis has its own role to play alongside signal processing and image processing.Concentrating its coverage on those 2-D signals coming from physical sensors (such as radars and sonars), the discussion explores a 2-D spectral approach but develops the modeling of 2-D signals and proposes several data-oriented analysis techniques for dealing with them. Coverage is also given to potential future developments in this area.

  8. Minimum signals in classical physics

    Institute of Scientific and Technical Information of China (English)

    邓文基; 许基桓; 刘平

    2003-01-01

    The bandwidth theorem for Fourier analysis on any time-dependent classical signal is shown using the operator approach to quantum mechanics. Following discussions about squeezed states in quantum optics, the problem of minimum signals presented by a single quantity and its squeezing is proposed. It is generally proved that all such minimum signals, squeezed or not, must be real Gaussian functions of time.

  9. Vertebrate Hedgehog signaling: cilia rule

    OpenAIRE

    Stainier Didier YR; Wilson Christopher W

    2010-01-01

    Abstract The Hedgehog (Hh) signaling pathway differentially utilizes the primary cilium in mammals and fruit flies. Recent work, including a study in BMC Biology, demonstrates that Hh signals through the cilium in zebrafish, clarifying the evolution of Hh signal transduction. See research article: http://www.biomedcentral.com/1741-7007/8/65

  10. Critical nodes in signalling pathways

    DEFF Research Database (Denmark)

    Taniguchi, Cullen M; Emanuelli, Brice; Kahn, C Ronald

    2006-01-01

    Physiologically important cell-signalling networks are complex, and contain several points of regulation, signal divergence and crosstalk with other signalling cascades. Here, we use the concept of 'critical nodes' to define the important junctions in these pathways and illustrate their unique ro...

  11. Rise-Time Distortion of Signal without Carrying Signal

    Science.gov (United States)

    Bukhman, N. S.

    2016-08-01

    The article deals with one-dimensional problem of rise-time distortion signal without carrying signal, that appears in the starting point intermittently, that is signal distortion at front edge or one of its derivative. The authors show that front edge of signal isn't distorted in case of propagation in unrestricted (including absorbing) area (amplitude of starting signal step or of one of its derivatives doesn't change) and move with the accuracy of vacuum light speed. The paper proves that it is the time interval shortage that causes signal loss with the route extension, but not the reduction of its starting amplitude, during which front edge of signal retains its starting value. The research presents new values for this time interval.

  12. Binary-Signal Recovery

    Science.gov (United States)

    Griebeler, Elmer L.

    2011-01-01

    Binary communication through long cables, opto-isolators, isolating transformers, or repeaters can become distorted in characteristic ways. The usual solution is to slow the communication rate, change to a different method, or improve the communication media. It would help if the characteristic distortions could be accommodated at the receiving end to ease the communication problem. The distortions come from loss of the high-frequency content, which adds slopes to the transitions from ones to zeroes and zeroes to ones. This weakens the definition of the ones and zeroes in the time domain. The other major distortion is the reduction of low frequency, which causes the voltage that defines the ones or zeroes to drift out of recognizable range. This development describes a method for recovering a binary data stream from a signal that has been subjected to a loss of both higher-frequency content and low-frequency content that is essential to define the difference between ones and zeroes. The method makes use of the frequency structure of the waveform created by the data stream, and then enhances the characteristics related to the data to reconstruct the binary switching pattern. A major issue is simplicity. The approach taken here is to take the first derivative of the signal and then feed it to a hysteresis switch. This is equivalent in practice to using a non-resonant band pass filter feeding a Schmitt trigger. Obviously, the derivative signal needs to be offset to halfway between the thresholds of the hysteresis switch, and amplified so that the derivatives reliably exceed the thresholds. A transition from a zero to a one is the most substantial, fastest plus movement of voltage, and therefore will create the largest plus first derivative pulse. Since the quiet state of the derivative is sitting between the hysteresis thresholds, the plus pulse exceeds the plus threshold, switching the hysteresis switch plus, which re-establishes the data zero to one transition

  13. Finding Signals for Plant Promoters

    Institute of Scientific and Technical Information of China (English)

    Weimou Zheng

    2003-01-01

    The strongest signal of plant promoter is searched with the model of single motif with two types. It turns out that the dominant type is the TATA-box. The other type may be called TATA-less signal, and may be used in gene finders for promoter recognition. While the TATA signals are very close for the monocot and the dicot, their TATA-less signals are significantly different. A general and flexible multi-motif model is also proposed for promoter analysis based on dynamic programming. By extending the Gibbs sampler to the dynamic programming and introducing temperature, an efficient algorithm is developed for searching signals in plant promoters.

  14. Detection of signals in noise

    CERN Document Server

    Whalen, Anthony D; Declaris, Nicholas

    1971-01-01

    Detection of Signals in Noise serves as an introduction to the principles and applications of the statistical theory of signal detection. The book discusses probability and random processes; narrowband signals, their complex representation, and their properties described with the aid of the Hilbert transform; and Gaussian-derived processes. The text also describes the application of hypothesis testing for the detection of signals and the fundamentals required for statistical detection of signals in noise. Problem exercises, references, and a supplementary bibliography are included after each c

  15. Signals and systems for dummies

    CERN Document Server

    Wickert, Mark

    2013-01-01

    Getting mixed signals in your signals and systems course? The concepts covered in a typical signals and systems course are often considered by engineering students to be some of the most difficult to master. Thankfully, Signals & Systems For Dummies is your intuitive guide to this tricky course, walking you step-by-step through some of the more complex theories and mathematical formulas in a way that is easy to understand. From Laplace Transforms to Fourier Analyses, Signals & Systems For Dummies explains in plain English the difficult concepts that can trip you up

  16. [Signal Processing Suite Design

    Science.gov (United States)

    Sahr, John D.; Mir, Hasan; Morabito, Andrew; Grossman, Matthew

    2003-01-01

    Our role in this project was to participate in the design of the signal processing suite to analyze plasma density measurements on board a small constellation (3 or 4) satellites in Low Earth Orbit. As we are new to space craft experiments, one of the challenges was to simply gain understanding of the quantity of data which would flow from the satellites, and possibly to interact with the design teams in generating optimal sampling patterns. For example, as the fleet of satellites were intended to fly through the same volume of space (displaced slightly in time and space), the bulk plasma structure should be common among the spacecraft. Therefore, an optimal, limited bandwidth data downlink would take advantage of this commonality. Also, motivated by techniques in ionospheric radar, we hoped to investigate the possibility of employing aperiodic sampling in order to gain access to a wider spatial spectrum without suffering aliasing in k-space.

  17. Olfactory receptor signaling.

    Science.gov (United States)

    Antunes, Gabriela; Simoes de Souza, Fabio Marques

    2016-01-01

    The guanine nucleotide protein (G protein)-coupled receptors (GPCRs) superfamily represents the largest class of membrane protein in the human genome. More than a half of all GPCRs are dedicated to interact with odorants and are termed odorant-receptors (ORs). Linda Buck and Richard Axel, the Nobel Prize laureates in physiology or medicine in 2004, first cloned and characterized the gene family that encode ORs, establishing the foundations to the understanding of the molecular basis for odor recognition. In the last decades, a lot of progress has been done to unravel the functioning of the sense of smell. This chapter gives a general overview of the topic of olfactory receptor signaling and reviews recent advances in this field. PMID:26928542

  18. Machine intelligence and signal processing

    CERN Document Server

    Vatsa, Mayank; Majumdar, Angshul; Kumar, Ajay

    2016-01-01

    This book comprises chapters on key problems in machine learning and signal processing arenas. The contents of the book are a result of a 2014 Workshop on Machine Intelligence and Signal Processing held at the Indraprastha Institute of Information Technology. Traditionally, signal processing and machine learning were considered to be separate areas of research. However in recent times the two communities are getting closer. In a very abstract fashion, signal processing is the study of operator design. The contributions of signal processing had been to device operators for restoration, compression, etc. Applied Mathematicians were more interested in operator analysis. Nowadays signal processing research is gravitating towards operator learning – instead of designing operators based on heuristics (for example wavelets), the trend is to learn these operators (for example dictionary learning). And thus, the gap between signal processing and machine learning is fast converging. The 2014 Workshop on Machine Intel...

  19. Unmixing binocular signals

    Directory of Open Access Journals (Sweden)

    Sidney R Lehky

    2011-08-01

    Full Text Available Incompatible images presented to the two eyes lead to perceptual oscillations in which one image at a time is visible. Early models portrayed this binocular rivalry as involving reciprocal inhibition between monocular representations of images, occurring at an early visual stage prior to binocular mixing. However, psychophysical experiments found conditions where rivalry could also occur at a higher, more abstract level of representation. In those cases, the rivalry was between image representations dissociated from eye-of-origin information, rather than between monocular representations from the two eyes. Moreover, neurophysiological recordings found the strongest rivalry correlate in inferotemporal cortex, a high-level, predominantly binocular visual area involved in object recognition, rather than early visual structures. An unresolved issue is how can the separate identities of the two images be maintained after binocular mixing in order for rivalry to be possible at higher levels? Here we demonstrate that after the two images are mixed, they can be unmixed at any subsequent stage using a physiologically plausible nonlinear signal-processing algorithm, non-negative matrix factorization, previously proposed for parsing object parts during object recognition. The possibility that unmixed left and right images can be regenerated at late stages within the visual system provides a mechanism for creating various binocular representations and interactions de novo in different cortical areas for different purposes, rather than inheriting then from early areas. This is a clear example how nonlinear algorithms can lead to highly non-intuitive behavior in neural information processing.

  20. Purinergic signaling in epilepsy.

    Science.gov (United States)

    Rassendren, François; Audinat, Etienne

    2016-09-01

    Until recently, analysis of the mechanisms underlying epilepsy was centered on neuron dysfunctions. Accordingly, most of the available pharmacological treatments aim at reducing neuronal excitation or at potentiating neuronal inhibition. These therapeutic options can lead to obvious secondary effects, and, moreover, seizures cannot be controlled by any known medication in one-third of the patients. A purely neurocentric view of brain functions and dysfunctions has been seriously questioned during the past 2 decades because of the accumulation of experimental data showing the functional importance of reciprocal interactions between glial cells and neurons. In the case of epilepsy, our current knowledge of the human disease and analysis of animal models clearly favor the involvement of astrocytes and microglial cells during the progression of the disease, including at very early stages, opening the way to the identification of new therapeutic targets. Purinergic signaling is a fundamental feature of neuron-glia interactions, and increasing evidence indicates that modifications of this pathway contribute to the functional remodeling of the epileptic brain. This Review discusses the recent experimental results indicating the roles of astrocytic and microglial P2X and P2Y receptors in epilepsy. © 2016 Wiley Periodicals, Inc. PMID:27302739

  1. Volcanic signals in oceans

    KAUST Repository

    Stenchikov, Georgiy L.

    2009-08-22

    Sulfate aerosols resulting from strong volcanic explosions last for 2–3 years in the lower stratosphere. Therefore it was traditionally believed that volcanic impacts produce mainly short-term, transient climate perturbations. However, the ocean integrates volcanic radiative cooling and responds over a wide range of time scales. The associated processes, especially ocean heat uptake, play a key role in ongoing climate change. However, they are not well constrained by observations, and attempts to simulate them in current climate models used for climate predictions yield a range of uncertainty. Volcanic impacts on the ocean provide an independent means of assessing these processes. This study focuses on quantification of the seasonal to multidecadal time scale response of the ocean to explosive volcanism. It employs the coupled climate model CM2.1, developed recently at the National Oceanic and Atmospheric Administration\\'s Geophysical Fluid Dynamics Laboratory, to simulate the response to the 1991 Pinatubo and the 1815 Tambora eruptions, which were the largest in the 20th and 19th centuries, respectively. The simulated climate perturbations compare well with available observations for the Pinatubo period. The stronger Tambora forcing produces responses with higher signal-to-noise ratio. Volcanic cooling tends to strengthen the Atlantic meridional overturning circulation. Sea ice extent appears to be sensitive to volcanic forcing, especially during the warm season. Because of the extremely long relaxation time of ocean subsurface temperature and sea level, the perturbations caused by the Tambora eruption could have lasted well into the 20th century.

  2. Angular signal radiography.

    Science.gov (United States)

    Li, Panyun; Zhang, Kai; Bao, Yuan; Ren, Yuqi; Ju, Zaiqiang; Wang, Yan; He, Qili; Zhu, Zhongzhu; Huang, Wanxia; Yuan, Qingxi; Zhu, Peiping

    2016-03-21

    Microscopy techniques using visible photons, x-rays, neutrons, and electrons have made remarkable impact in many scientific disciplines. The microscopic data can often be expressed as the convolution of the spatial distribution of certain properties of the specimens and the inherent response function of the imaging system. The x-ray grating interferometer (XGI), which is sensitive to the deviation angle of the incoming x-rays, has attracted significant attention in the past years due to its capability in achieving x-ray phase contrast imaging with low brilliance source. However, the comprehensive and analytical theoretical framework is yet to be presented. Herein, we propose a theoretical framework termed angular signal radiography (ASR) to describe the imaging process of the XGI system in a classical, comprehensive and analytical manner. We demonstrated, by means of theoretical deduction and synchrotron based experiments, that the spatial distribution of specimens' physical properties, including absorption, refraction and scattering, can be extracted by ASR in XGI. Implementation of ASR in XGI offers advantages such as simplified phase retrieval algorithm, reduced overall radiation dose, and improved image acquisition speed. These advantages, as well as the limitations of the proposed method, are systematically investigated in this paper. PMID:27136780

  3. Steganography in arrhythmic electrocardiogram signal.

    Science.gov (United States)

    Edward Jero, S; Ramu, Palaniappan; Ramakrishnan, S

    2015-08-01

    Security and privacy of patient data is a vital requirement during exchange/storage of medical information over communication network. Steganography method hides patient data into a cover signal to prevent unauthenticated accesses during data transfer. This study evaluates the performance of ECG steganography to ensure secured transmission of patient data where an abnormal ECG signal is used as cover signal. The novelty of this work is to hide patient data into two dimensional matrix of an abnormal ECG signal using Discrete Wavelet Transform and Singular Value Decomposition based steganography method. A 2D ECG is constructed according to Tompkins QRS detection algorithm. The missed R peaks are computed using RR interval during 2D conversion. The abnormal ECG signals are obtained from the MIT-BIH arrhythmia database. Metrics such as Peak Signal to Noise Ratio, Percentage Residual Difference, Kullback-Leibler distance and Bit Error Rate are used to evaluate the performance of the proposed approach.

  4. Steganography in arrhythmic electrocardiogram signal.

    Science.gov (United States)

    Edward Jero, S; Ramu, Palaniappan; Ramakrishnan, S

    2015-08-01

    Security and privacy of patient data is a vital requirement during exchange/storage of medical information over communication network. Steganography method hides patient data into a cover signal to prevent unauthenticated accesses during data transfer. This study evaluates the performance of ECG steganography to ensure secured transmission of patient data where an abnormal ECG signal is used as cover signal. The novelty of this work is to hide patient data into two dimensional matrix of an abnormal ECG signal using Discrete Wavelet Transform and Singular Value Decomposition based steganography method. A 2D ECG is constructed according to Tompkins QRS detection algorithm. The missed R peaks are computed using RR interval during 2D conversion. The abnormal ECG signals are obtained from the MIT-BIH arrhythmia database. Metrics such as Peak Signal to Noise Ratio, Percentage Residual Difference, Kullback-Leibler distance and Bit Error Rate are used to evaluate the performance of the proposed approach. PMID:26736533

  5. Integrins mediating bone signal transduction

    Institute of Scientific and Technical Information of China (English)

    HE Chuanglong; WANG Yuanliang; YANG Lihua; ZHANG Jun

    2004-01-01

    Integrin-mediated adhesions play critical roles in diverse cell functions. Integrins offers a platform on which mechanical stimuli, cytoskeletal organization, biochemical signals can concentrate. Mechanical stimuli transmitted by integrins influence the cytoskeleton, in turn, the cytoskeleton influences cell adhesion via integrins, then cell adhesion results in a series of signal transduction cascades. In skeleton, integrins also have a key role for bone resoption by osteoclasts and reformation by osteoblasts. In present review, the proteins involved in integrin signal transduction and integrin signal transduction pathways were discussed, mainly on the basic mechanisms of integrin signaling and the roles of integrins in bone signal transduction, which may give insight into new therapeutic agents to all kinds of skeletal diseases and new strategies for bone tissue engineering.

  6. Ultrasound imaging using coded signals

    DEFF Research Database (Denmark)

    Misaridis, Athanasios

    Modulated (or coded) excitation signals can potentially improve the quality and increase the frame rate in medical ultrasound scanners. The aim of this dissertation is to investigate systematically the applicability of modulated signals in medical ultrasound imaging and to suggest appropriate...... of the excitation signal. Although a gain in signal-to-noise ratio of about 20 dB is theoretically possible for the time-bandwidth product available in ultrasound, it is shown that the effects of transducer weighting and tissue attenuation reduce the maximum gain at 10 dB for robust compression with low sidelobes...... is described. Application of coded excitation in array imaging is evaluated through simulations in Field II. The low degree of the orthogonality among coded signals for ultrasound systems is first discussed, and the effect of mismatched filtering in the cross-correlation properties of the signals is evaluated...

  7. Sub-lethal irradiation of human colorectal tumor cells imparts enhanced and sustained susceptibility to multiple death receptor signaling pathways.

    Directory of Open Access Journals (Sweden)

    Victoria Ifeadi

    Full Text Available BACKGROUND: Death receptors (DR of the TNF family function as anti-tumor immune effector molecules. Tumor cells, however, often exhibit DR-signaling resistance. Previous studies indicate that radiation can modify gene expression within tumor cells and increase tumor cell sensitivity to immune attack. The aim of this study is to investigate the synergistic effect of sub-lethal doses of ionizing radiation in sensitizing colorectal carcinoma cells to death receptor-mediated apoptosis. METHODOLOGY/PRINCIPAL FINDINGS: The ability of radiation to modulate the expression of multiple death receptors (Fas/CD95, TRAILR1/DR4, TRAILR2/DR5, TNF-R1 and LTβR was examined in colorectal tumor cells. The functional significance of sub-lethal doses of radiation in enhancing tumor cell susceptibility to DR-induced apoptosis was determined by in vitro functional sensitivity assays. The longevity of these changes and the underlying molecular mechanism of irradiation in sensitizing diverse colorectal carcinoma cells to death receptor-mediated apoptosis were also examined. We found that radiation increased surface expression of Fas, DR4 and DR5 but not LTβR or TNF-R1 in these cells. Increased expression of DRs was observed 2 days post-irradiation and remained elevated 7-days post irradiation. Sub-lethal tumor cell irradiation alone exhibited minimal cell death, but effectively sensitized three of three colorectal carcinoma cells to both TRAIL and Fas-induced apoptosis, but not LTβR-induced death. Furthermore, radiation-enhanced Fas and TRAIL-induced cell death lasted as long as 5-days post-irradiation. Specific analysis of intracellular sensitizers to apoptosis indicated that while radiation did reduce Bcl-X(L and c-FLIP protein expression, this reduction did not correlate with the radiation-enhanced sensitivity to Fas and/or TRAIL mediated apoptosis among the three cell types. CONCLUSIONS/SIGNIFICANCE: Irradiation of tumor cells can overcome Fas and TRAIL

  8. Semi-classical signal analysis

    KAUST Repository

    Laleg-Kirati, Taous-Meriem

    2012-09-30

    This study introduces a new signal analysis method, based on a semi-classical approach. The main idea in this method is to interpret a pulse-shaped signal as a potential of a Schrödinger operator and then to use the discrete spectrum of this operator for the analysis of the signal. We present some numerical examples and the first results obtained with this method on the analysis of arterial blood pressure waveforms. © 2012 Springer-Verlag London Limited.

  9. Introduction to digital signal processing

    CERN Document Server

    Kuc, Roman

    2008-01-01

    This book approaches digital Signal Processing and filter design in a Novel way, by presenting the relevant theory and then having the Student apply it by implementing signal processing routines on a computer. This mixture of theory and application has worked successfully. With this approach, the students receive a deeper and intuitive understanding of the theory, its applications and its limitations. This text also includes projects that require students to write Computer programs to accomplish signal processing projects.

  10. Image quality. Signals and information

    International Nuclear Information System (INIS)

    Among many parameters relating image quality, neutrons and observed signals prior to handle observed signals are considered in this report. A relation between signals and their qualities on neutron images is studied considering on neutron intensity and its statistical character, effective energy, and characteristic of neutron detection systems. Geometrical parameter of neutron beam is discussed as the other importance to characterize image quality.(author)

  11. Fundamentals of statistical signal processing

    CERN Document Server

    Kay, Steven M

    1993-01-01

    A unified presentation of parameter estimation for those involved in the design and implementation of statistical signal processing algorithms. Covers important approaches to obtaining an optimal estimator and analyzing its performance; and includes numerous examples as well as applications to real- world problems. MARKETS: For practicing engineers and scientists who design and analyze signal processing systems, i.e., to extract information from noisy signals — radar engineer, sonar engineer, geophysicist, oceanographer, biomedical engineer, communications engineer, economist, statistician, physicist, etc.

  12. Semi-classical signal analysis

    CERN Document Server

    Laleg-Kirati, Taous-Meriem; Sorine, Michel

    2010-01-01

    This study introduces a new signal analysis method called SCSA, based on a semi-classical approach. The main idea in the SCSA is to interpret a pulse-shaped signal as a potential of a Schr\\"odinger operator and then to use the discrete spectrum of this operator for the analysis of the signal. We present some numerical examples and the first results obtained with this method on the analysis of arterial blood pressure waveforms.

  13. Gibberellin Signal Transduction in Rice

    Institute of Scientific and Technical Information of China (English)

    Liu-Min Fan; Xiaoyan Feng; Yu Wang; Xing Wang Deng

    2007-01-01

    In the past decade, significant knowledge has accumulated regarding gibberellin (GA) signal transduction in rice as a result of studies using multiple approaches, particularly molecular genetics. The present review highlights the recent developments in the identification of GA signaling pathway components, the discovery of GA-induced destruction of GA signaling represser (DELLA protein), and the possible mechanism underlying the regulation of GA-responsive gene expression in rice.

  14. Pragmatic circuits signals and filters

    CERN Document Server

    Eccles, William

    2006-01-01

    Pragmatic Circuits: Signals and Filters is built around the processing of signals. Topics include spectra, a short introduction to the Fourier series, design of filters, and the properties of the Fourier transform. The focus is on signals rather than power. But the treatment is still pragmatic. For example, the author accepts the work of Butterworth and uses his results to design filters in a fairly methodical fashion. This third of three volumes finishes with a look at spectra by showing how to get a spectrum even if a signal is not periodic. The Fourier transform provides a way of dealing wi

  15. Rhomboids, signalling and cell biology.

    Science.gov (United States)

    Freeman, Matthew

    2016-06-15

    Here, I take a somewhat personal perspective on signalling control, focusing on the rhomboid-like superfamily of proteins that my group has worked on for almost 20 years. As well as describing some of the key and recent advances, I attempt to draw out signalling themes that emerge. One important message is that the genetic and biochemical perspective on signalling has tended to underplay the importance of cell biology. There is clear evidence that signalling pathways exploit the control of intracellular trafficking, protein quality control and degradation and other cell biological phenomena, as important regulatory opportunities.

  16. Inactivation of Akt by arsenic trioxide induces cell death via mitochondrial-mediated apoptotic signaling in SGC-7901 human gastric cancer cells.

    Science.gov (United States)

    Gao, Yan-Hui; Zhang, Hao-Peng; Yang, Shu-Meng; Yang, Yue; Ma, Yu-Yan; Zhang, Xin-Yu; Yang, Yan-Mei

    2014-04-01

    Arsenic trioxide (As2O3) has been recognized as a potential chemotherapeutic agent, yet the details concerning its mechanism of action in solid cancers remain undetermined. The present study assessed the role of Akt in the cell death induced by As2O3. The MTT assay showed that As2O3 suppressed the proliferation of SGC-7901 cells in a dose- and time-dependent manner. Characteristic apoptotic changes were observed in the As2O3‑treated cells by Hoechst 33342 staining, and FACS analysis showed that As2O3 caused dose-dependent apoptotic cell death. As2O3 activated caspase-3 and -9, and PARP cleavage in a dose-dependent manner. Compromised mitochondrial membrane potential and an increased protein level of Bax indicated involvement of mitochondia. As2O3 decreased the levels of p-Akt (Ser473), p-Akt (Thr308) and p-GSK-3β (Ser9), suggesting that As2O3 inactivated Akt kinase. In addition, LY294002 (a PI3 kinase inhibitor) augmented the apoptosis induced by As2O3. These results demonstrated that inhibition of PI3K/Akt signaling was involved in As2O3-induced apoptosis of gastric cancer SGC-7901 cells. PMID:24482137

  17. Signal transduction by growth factor receptors: signaling in an instant

    DEFF Research Database (Denmark)

    Dengjel, Joern; Akimov, Vyacheslav; Blagoev, Blagoy;

    2007-01-01

    -out by mass spectrometry-based proteomics has allowed exciting views on the very early events in signal transduction. Activation profiles of regulated phosphorylation sites on epidermal growth factor receptor and downstream signal transducers showed different kinetics within the first ten seconds...

  18. Correlation theory-based signal processing method for CMF signals

    Science.gov (United States)

    Shen, Yan-lin; Tu, Ya-qing

    2016-06-01

    Signal processing precision of Coriolis mass flowmeter (CMF) signals affects measurement accuracy of Coriolis mass flowmeters directly. To improve the measurement accuracy of CMFs, a correlation theory-based signal processing method for CMF signals is proposed, which is comprised of the correlation theory-based frequency estimation method and phase difference estimation method. Theoretical analysis shows that the proposed method eliminates the effect of non-integral period sampling signals on frequency and phase difference estimation. The results of simulations and field experiments demonstrate that the proposed method improves the anti-interference performance of frequency and phase difference estimation and has better estimation performance than the adaptive notch filter, discrete Fourier transform and autocorrelation methods in terms of frequency estimation and the data extension-based correlation, Hilbert transform, quadrature delay estimator and discrete Fourier transform methods in terms of phase difference estimation, which contributes to improving the measurement accuracy of Coriolis mass flowmeters.

  19. Activating Transcription Factor 4 (ATF4)-ATF3-C/EBP Homologous Protein (CHOP) Cascade Shows an Essential Role in the ER Stress-Induced Sensitization of Tetrachlorobenzoquinone-Challenged PC12 Cells to ROS-Mediated Apoptosis via Death Receptor 5 (DR5) Signaling.

    Science.gov (United States)

    Liu, Zixuan; Shi, Qiong; Song, Xiufang; Wang, Yuxin; Wang, Yawen; Song, Erqun; Song, Yang

    2016-09-19

    Tetrachlorobenzoquinone (TCBQ) is a downstream metabolite of pentachlorophenol (PCP). Previously, we demonstrated that TCBQ caused cytotoxicity due to mitochondrial-related apoptosis. Here, we confirmed the upregulation of death receptor 5 (DR5) followed by the construction of the death-inducing signaling complex (DISC). We also detected the activation of the caspase cascade, which was correlated with TCBQ-induced apoptotic cell death in PC12 cells. The upregulation of DR5 included transcriptional activation and de novo protein synthesis in response to TCBQ. We also identified the endoplasmic reticulum (ER) as a new target for the TCBQ challenge in PC12 cells. The protein kinase R-like ER kinase/eukaryotic translation initiation factor 2α (PERK/eIF2α)-mediated activating transcription factor 4 (ATF4)-ATF3-C/EBP homologous protein (CHOP) signaling pathway contributed to the process of TCBQ-induced ER stress. Blocking ATF4, ATF3, or CHOP signaling by gene silencing technology resulted in decreased cell apoptosis after exposure to TCBQ. Finally, NAC ameliorated TCBQ-induced apoptosis and ER stress, which illustrated that TCBQ-induced apoptosis is somehow ROS-dependent. In summary, this study provided important mechanistic insight into how TCBQ utilizes ER stress-related signaling to exhibit pro-apoptotic activity in PC12 cells. PMID:27484784

  20. Ramentaceone, a Naphthoquinone Derived from Drosera sp., Induces Apoptosis by Suppressing PI3K/Akt Signaling in Breast Cancer Cells.

    Science.gov (United States)

    Kawiak, Anna; Lojkowska, Ewa

    2016-01-01

    The phosphoinositide 3-kinase (PI3K) signaling pathway plays an important role in processes critical for breast cancer progression and its upregulation confers increased resistance of cancer cells to chemotherapy and radiation. The present study aimed at determining the activity of ramentaceone, a constituent of species in the plant genera Drosera, toward breast cancer cells and defining the involvement of PI3K/Akt inhibition in ramentaceone-mediated cell death induction. The results showed that ramentaceone exhibited high antiproliferative activity toward breast cancer cells, in particular HER2-overexpressing breast cancer cells. The mode of cell death induced by ramentaceone was through apoptosis as determined by cytometric analysis of caspase activity and Annexin V staining. Apoptosis induction was found to be mediated by inhibition of PI3K/Akt signaling and through targeting its downstream anti-apoptotic effectors. Ramentaceone inhibited PI3-kinase activity, reduced the expression of the PI3K protein and inhibited the phosphorylation of the Akt protein in breast cancer cells. The expression of the anti-apoptotic Bcl-2 protein was decreased and the levels of the pro-apoptotic proteins, Bax and Bak, were elevated. Moreover, inhibition of PI3K and silencing of Akt expression increased the sensitivity of cells to ramentaceone-induced apoptosis. In conclusion, our results indicate that ramentaceone induces apoptosis in breast cancer cells through PI3K/Akt signaling inhibition. These findings suggest further investigation of ramentaceone as a potential therapeutic agent in breast cancer therapy, in particular HER2-positive breast cancer. PMID:26840401

  1. Ramentaceone, a Naphthoquinone Derived from Drosera sp., Induces Apoptosis by Suppressing PI3K/Akt Signaling in Breast Cancer Cells.

    Directory of Open Access Journals (Sweden)

    Anna Kawiak

    Full Text Available The phosphoinositide 3-kinase (PI3K signaling pathway plays an important role in processes critical for breast cancer progression and its upregulation confers increased resistance of cancer cells to chemotherapy and radiation. The present study aimed at determining the activity of ramentaceone, a constituent of species in the plant genera Drosera, toward breast cancer cells and defining the involvement of PI3K/Akt inhibition in ramentaceone-mediated cell death induction. The results showed that ramentaceone exhibited high antiproliferative activity toward breast cancer cells, in particular HER2-overexpressing breast cancer cells. The mode of cell death induced by ramentaceone was through apoptosis as determined by cytometric analysis of caspase activity and Annexin V staining. Apoptosis induction was found to be mediated by inhibition of PI3K/Akt signaling and through targeting its downstream anti-apoptotic effectors. Ramentaceone inhibited PI3-kinase activity, reduced the expression of the PI3K protein and inhibited the phosphorylation of the Akt protein in breast cancer cells. The expression of the anti-apoptotic Bcl-2 protein was decreased and the levels of the pro-apoptotic proteins, Bax and Bak, were elevated. Moreover, inhibition of PI3K and silencing of Akt expression increased the sensitivity of cells to ramentaceone-induced apoptosis. In conclusion, our results indicate that ramentaceone induces apoptosis in breast cancer cells through PI3K/Akt signaling inhibition. These findings suggest further investigation of ramentaceone as a potential therapeutic agent in breast cancer therapy, in particular HER2-positive breast cancer.

  2. Signaling a Change of Heart

    DEFF Research Database (Denmark)

    Schumacher, Gijs

    2011-01-01

    introduced welfare state retrenchment measures. Social Democrats can win votes and join coalitions by shifting rightwards. In contrast, they can pursue policy objectives by shifting leftwards. To communicate these shifts, in other words, ‘changes of heart’, parties send signals to voters and other parties...... after having signalled ‘a change of heart’....

  3. Signals in Communication Engineering History

    Science.gov (United States)

    Consonni, Denise; Silva, Magno T. M.

    2010-01-01

    This paper is a study of various electric signals, which have been employed throughout the history of communication engineering in its two main landmarks: the telegraph and the telephone. The signals are presented in their time and frequency domain representations. The historical order has been followed in the presentation: wired systems, spark…

  4. Parallel Computers in Signal Processing

    Directory of Open Access Journals (Sweden)

    Narsingh Deo

    1985-07-01

    Full Text Available Signal processing often requires a great deal of raw computing power for which it is important to take a look at parallel computers. The paper reviews various types of parallel computer architectures from the viewpoint of signal and image processing.

  5. Hippo signalling directs intestinal fate

    DEFF Research Database (Denmark)

    le Bouteiller, Marie Catherine M; Jensen, Kim Bak

    2015-01-01

    Hippo signalling has been associated with many important tissue functions including the regulation of organ size. In the intestinal epithelium differing functions have been proposed for the effectors of Hippo signalling, YAP and TAZ1. These are now shown to have a dual role in the intestinal...

  6. The Pseudomonas Quinolone Signal (PQS)

    DEFF Research Database (Denmark)

    Sams, Thomas; Baker, Ysobel; Hodgkinson, James;

    2015-01-01

    is now known to be under the con-trol of the quorum sensing (QS) system. Over the last15 years, the Pseudomonas quinolone signal (PQS) has beenfound to play a crucial role in QS by linking the two seg-ments (las and rhl) of the P. aeruginosa N-acylhomoserinelactone-dependent QS signaling pathways...

  7. Echolocation signals of wild dolphins

    Science.gov (United States)

    Au, W. W. L.

    2004-07-01

    Most of our understanding of dolphin echolocation has come from studies of captive dolphins performing various echolocation tasks. Recently, measurements of echolocation signals in the wild have expanded our understanding of the characteristics of these signals in a natural setting. Measuring undistorted dolphin echolocation signals with free swimming dolphins in the field can be a challenging task. A four hydrophone array arranged in a symmetrical star pattern was used to measure the echolocation signals of four species of dolphins in the wild. Echolocation signals of the following dolphins have been measured with the symmetrical star array: white-beaked dolphins in Iceland, Atlantic spotted dolphins in the Bahamas, killer whales in British Columbia, and dusky dolphins in New Zealand. There are many common features in the echolocation signals of the different species. Most of the signals had spectra that were bimodal: two peaks, one at low frequencies and another about an octave higher in frequency. The source level of the sonar transmission varies as a function of 20log R, suggesting a form of time-varying gain but on the transmitting end of the sonar process rather than the receiving end. The results of the field work call into question the issue of whether the signals used by captive dolphins may be shaped by the task they are required to perform rather than what they would do more naturally.

  8. Retrograde signaling: Organelles go networking.

    Science.gov (United States)

    Kleine, Tatjana; Leister, Dario

    2016-08-01

    The term retrograde signaling refers to the fact that chloroplasts and mitochondria utilize specific signaling molecules to convey information on their developmental and physiological states to the nucleus and modulate the expression of nuclear genes accordingly. Signals emanating from plastids have been associated with two main networks: 'Biogenic control' is active during early stages of chloroplast development, while 'operational' control functions in response to environmental fluctuations. Early work focused on the former and its major players, the GUN proteins. However, our view of retrograde signaling has since been extended and revised. Elements of several 'operational' signaling circuits have come to light, including metabolites, signaling cascades in the cytosol and transcription factors. Here, we review recent advances in the identification and characterization of retrograde signaling components. We place particular emphasis on the strategies employed to define signaling components, spanning the entire spectrum of genetic screens, metabolite profiling and bioinformatics. This article is part of a Special Issue entitled 'EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2-6, 2016', edited by Prof. Paolo Bernardi. PMID:26997501

  9. Signals and systems with MATLAB

    CERN Document Server

    Yang, Won Young; Song, Ik H; Cho, Yong S

    2009-01-01

    Covers some of the theoretical foundations and mathematical derivations that can be used in higher-level related subjects such as signal processing, communication, and control, minimizing the mathematical difficulty and computational burden. This book illustrates the usage of MATLAB and Simulink for signal and system analysis and design.

  10. Fining Signals for Plant Promoters

    Institute of Scientific and Technical Information of China (English)

    WeimouZheng

    2003-01-01

    The strongest signal of plant promoter is searched with the model of single motif with two types.It turns out that the dominant type is the TATA-box.The other type may be called TATA-less signal,and may be used in gene finders for promoter recognition.While the TATA signals are very close for the monocot and the dicot,their TATA-less signals are significantly different.A general and flexible multi-motif model is also proposed for promoter analysis based on dynamic programming.By extending the Gibbs sampler to the dynamic programming and introducing temperature,an efficient algorithm is developed for searching signals in plant promoters.

  11. Aberrant Signaling Pathways in Glioma

    International Nuclear Information System (INIS)

    Glioblastoma multiforme (GBM), a WHO grade IV malignant glioma, is the most common and lethal primary brain tumor in adults; few treatments are available. Median survival rates range from 12–15 months. The biological characteristics of this tumor are exemplified by prominent proliferation, active invasiveness, and rich angiogenesis. This is mainly due to highly deregulated signaling pathways in the tumor. Studies of these signaling pathways have greatly increased our understanding of the biology and clinical behavior of GBM. An integrated view of signal transduction will provide a more useful approach in designing novel therapies for this devastating disease. In this review, we summarize the current understanding of GBM signaling pathways with a focus on potential molecular targets for anti-signaling molecular therapies

  12. Recovery of Sparsely Corrupted Signals

    CERN Document Server

    Studer, Christoph; Pope, Graeme; Bölcskei, Helmut

    2011-01-01

    We investigate the recovery of signals exhibiting a sparse representation in a general (i.e., possibly redundant or incomplete) dictionary that are corrupted by additive noise admitting a sparse representation in another general dictionary. This setup covers a wide range of applications, such as image inpainting, super-resolution, signal separation, and recovery of signals that are impaired by, e.g., clipping, impulse noise, or narrowband interference. We present deterministic recovery guarantees based on a novel uncertainty relation for pairs of general dictionaries and we provide corresponding practicable recovery algorithms. The recovery guarantees we find depend on the signal and noise sparsity levels, on the coherence parameters of the involved dictionaries, and on the amount of prior knowledge on the support sets of signal and noise. We finally identify situations under which the recovery guarantees are tight.

  13. Engineering cell-cell signaling.

    Science.gov (United States)

    Blagovic, Katarina; Gong, Emily S; Milano, Daniel F; Natividad, Robert J; Asthagiri, Anand R

    2013-10-01

    Juxtacrine cell-cell signaling mediated by the direct interaction of adjoining mammalian cells is arguably the mode of cell communication that is most recalcitrant to engineering. Overcoming this challenge is crucial for progress in biomedical applications, such as tissue engineering, regenerative medicine, immune system engineering and therapeutic design. Here, we describe the significant advances that have been made in developing synthetic platforms (materials and devices) and synthetic cells (cell surface engineering and synthetic gene circuits) to modulate juxtacrine cell-cell signaling. In addition, significant progress has been made in elucidating design rules and strategies to modulate juxtacrine signaling on the basis of quantitative, engineering analysis of the mechanical and regulatory role of juxtacrine signals in the context of other cues and physical constraints in the microenvironment. These advances in engineering juxtacrine signaling lay a strong foundation for an integrative approach to utilize synthetic cells, advanced 'chassis' and predictive modeling to engineer the form and function of living tissues.

  14. Perception and Signaling of Strigolactones.

    Science.gov (United States)

    Marzec, Marek

    2016-01-01

    Strigolactones (SLs), a recently discovered class of phytohormones, are important regulators of plant growth and development. While the biosynthetic pathway of these molecules is well documented, until recently there was not much known about the molecular mechanisms underlying SL perception and signal transduction in plants. Certain aspects of their perception and signaling, including the hormone-mediated interaction between receptor and F-box protein, degradation of suppressor proteins and activation of transcription factors, are also found in other phytohormones. However, some of SL signaling features seem to be specific for the SL signaling pathway. These include the enzymatic activity of the SL receptor and its destabilization caused by SLs. This review summarizes the current knowledge about SL signaling pathway in plants. PMID:27602041

  15. Reinforcement learning in signaling game

    CERN Document Server

    Hu, Yilei; Tarrès, Pierre

    2011-01-01

    We consider a signaling game originally introduced by Skyrms, which models how two interacting players learn to signal each other and thus create a common language. The first rigorous analysis was done by Argiento, Pemantle, Skyrms and Volkov (2009) with 2 states, 2 signals and 2 acts. We study the case of M_1 states, M_2 signals and M_1 acts for general M_1, M_2. We prove that the expected payoff increases in average and thus converges a.s., and that a limit bipartite graph emerges, such that no signal-state correspondence is associated to both a synonym and an informational bottleneck. Finally, we show that any graph correspondence with the above property is a limit configuration with positive probability.

  16. Role of apoptosis and necrosis in cell death induced by nanoparticle-mediated photothermal therapy

    Energy Technology Data Exchange (ETDEWEB)

    Pattani, Varun P., E-mail: varun.pattani@utexas.edu; Shah, Jay; Atalis, Alexandra; Sharma, Anirudh; Tunnell, James W. [The University of Texas at Austin, Department of Biomedical Engineering (United States)

    2015-01-15

    Current cancer therapies can cause significant collateral damage due to a lack of specificity and sensitivity. Therefore, we explored the cell death pathway response to gold nanorod (GNR)-mediated photothermal therapy as a highly specific cancer therapeutic to understand the role of apoptosis and necrosis during intense localized heating. By developing this, we can optimize photothermal therapy to induce a maximum of ‘clean’ cell death pathways, namely apoptosis, thereby reducing external damage. GNRs were targeted to several subcellular localizations within colorectal tumor cells in vitro, and the cell death pathways were quantitatively analyzed after photothermal therapy using flow cytometry. In this study, we found that the cell death response to photothermal therapy was dependent on the GNR localization. Furthermore, we demonstrated that nanorods targeted to the perinuclear region irradiated at 37.5 W/cm{sup 2} laser fluence rate led to maximum cell destruction with the ‘cleaner’ method of apoptosis, at similar percentages as other anti-cancer targeted therapies. We believe that this indicates the therapeutic potential for GNR-mediated photothermal therapy to treat cancer effectively without causing damage to surrounding tissue.

  17. Ku70 acetylation mediates neuroblastoma cell death induced by histone deacetylase inhibitors

    OpenAIRE

    Subramanian, Chitra; Opipari, Anthony W.; Bian, Xin; Castle, Valerie P; Kwok, Roland P S

    2005-01-01

    Histone deacetylase inhibitors (HDACIs) are therapeutic drugs that inhibit deacetylase activity, thereby increasing acetylation of many proteins, including histones. HDACIs have antineoplastic effects in preclinical and clinical trials and are being considered for cancers with unmet therapeutic need, including neuroblastoma (NB). Uncertainty of how HDACI-induced protein acetylation leads to cell death, however, makes it difficult to determine which tumors are likely to be responsive to these ...

  18. Hydrogen peroxide contributes to the epithelial cell death induced by the oral mitis group of streptococci.

    Directory of Open Access Journals (Sweden)

    Nobuo Okahashi

    Full Text Available Members of the mitis group of streptococci are normal inhabitants of the commensal flora of the oral cavity and upper respiratory tract of humans. Some mitis group species, such as Streptococcus oralis and Streptococcus sanguinis, are primary colonizers of the human oral cavity. Recently, we found that hydrogen peroxide (H2O2 produced by S. oralis is cytotoxic to human macrophages, suggesting that streptococcus-derived H2O2 may act as a cytotoxin. Since epithelial cells provide a physical barrier against pathogenic microbes, we investigated their susceptibility to infection by H2O2-producing streptococci in this study. Infection by S. oralis and S. sanguinis was found to stimulate cell death of Detroit 562, Calu-3 and HeLa epithelial cell lines at a multiplicity of infection greater than 100. Catalase, an enzyme that catalyzes the decomposition of H2O2, inhibited S. oralis cytotoxicity, and H2O2 alone was capable of eliciting epithelial cell death. Moreover, S. oralis mutants lacking the spxB gene encoding pyruvate oxidase, which are deficient in H2O2 production, exhibited reduced cytotoxicity toward Detroit 562 epithelial cells. In addition, enzyme-linked immunosorbent assays revealed that both S. oralis and H2O2 induced interleukin-6 production in Detroit 562 epithelial cells. These results suggest that streptococcal H2O2 is cytotoxic to epithelial cells, and promotes bacterial evasion of the host defense systems in the oral cavity and upper respiratory tracts.

  19. Role of mitochondria-associated hexokinase II in cancer cell death induced by 3-Bromopyruvate

    OpenAIRE

    Chen, Zhao; Zhang, Hui; Lu, Weiqin; Huang, Peng

    2009-01-01

    It has long been observed that cancer cells rely more on glycolysis to generate ATP and actively use certain glycolytic metabolic intermediates for biosynthesis. Hexokinase II (HKII) is a key glycolytic enzyme that plays a role in the regulation of the mitochondria-initiated apoptotic cell death. As a potent inhibitor of hexokinase, 3-bromopyruvate (3-BrPA) is known to inhibit cancer cell energy metabolism and trigger cell death, supposedly through depletion of cellular ATP. The current study...

  20. CYTOTOXICITY AND MODE OF CELL DEATH INDUCED BY TRIPHENYLTIN (IV COMPOUNDS IN VITRO

    Directory of Open Access Journals (Sweden)

    Normah Awang

    2014-01-01

    Full Text Available A series of newly synthesized organotin (IV with N-alkyl-N-phenyldithiocarbamate ligands namely triphenyltin (IV ethylphenyldithiocarbamate (compound 1 and triphenyltin (IV butylphenyldithiocarbamate (compound 2 were assessed for their cytotoxic effect against HT-29 human colon adenocarcinoma cells and human CCD-18Co normal colon cells. The cytotoxicity of these organotins in both cells was assessed using 3-(4,5-dimethylthiazol-2-yl-2, 5-diphenyltetrazholium bromide (MTT assay upon 24 h treatment. Both compounds demonstrated potent cytotoxicity towards HT-29 cells with the IC50 of 0.18 µM for compound 1 and 0.20 µM for compound 2. Interestingly, compound 1 exhibited lower cytotoxicity towards CCD-18Co with IC50 of 1.55 µM whereas no IC50 was detected for compound 2 up to 2 µM treatment. The mode of cell death was determined based on the externalization of phosphatidylserine using flow cytometry. Cells treated with compound 1 and compound 2 were mainly viable and the apoptotic cell death was around 10% which suggests that both compounds induced growth arrest. In conclusion, this study demonstrated that both compounds were selective towards human colorectal cells by giving a strong cytotoxicity to cancer cells and low toxicity towards normal cells. Both compounds were suggested to induce growth arrest in HT-29 cells.

  1. Delayed luminescence to monitor programmed cell death induced by berberine on thyroid cancer cells

    Science.gov (United States)

    Scordino, Agata; Campisi, Agata; Grasso, Rosaria; Bonfanti, Roberta; Gulino, Marisa; Iauk, Liliana; Parenti, Rosalba; Musumeci, Francesco

    2014-11-01

    Correlation between apoptosis and UVA-induced ultraweak photon emission delayed luminescence (DL) from tumor thyroid cell lines was investigated. In particular, the effects of berberine, an alkaloid that has been reported to have anticancer activities, on two cancer cell lines were studied. The FTC-133 and 8305C cell lines, as representative of follicular and anaplastic thyroid human cancer, respectively, were chosen. The results show that berberine is able to arrest cell cycle and activate apoptotic pathway as shown in both cell lines by deoxyribonucleic acid fragmentation, caspase-3 cleavage, p53 and p27 protein overexpression. In parallel, changes in DL spectral components after berberine treatment support the hypothesis that DL from human cells originates mainly from mitochondria, since berberine acts especially at the mitochondrial level. The decrease of DL blue component for both cell lines could be related to the decrease of intra-mitochondrial nicotinamide adenine dinucleotide and may be a hallmark of induced apoptosis. In contrast, the response in the red spectral range is different for the two cell lines and may be ascribed to a different iron homeostasis.

  2. Inhibition of apoptic cell death induced by Pseudomonas syringae pv. Tabaci and mycotoxin fumonisin B1

    NARCIS (Netherlands)

    Iakimova, E.T.; Batchvorova, R.; Kapchina, V.; Popov, T.; Atanassov, A.; Woltering, E.J.

    2004-01-01

    The impact of programmed cell death (PCD) inhibitors on lesion formation and biochemical events in transgenic (ttr line) and non-transgenic (Nevrokop 1164) tobacco infected with Pseudomonas syringae pv. tabaci was tested. Programmed cell death in tomato cell culture was induced by Fumonisin B1 (FUM)

  3. Coronatine inhibits stomatal closure and delays hypersensitive response cell death induced by nonhost bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Seonghee Lee

    2013-02-01

    Full Text Available Pseudomonas syringae is the most widespread bacterial pathogen in plants. Several strains of P. syringae produce a phytotoxin, coronatine (COR, which acts as a jasmonic acid mimic and inhibits plant defense responses and contributes to disease symptom development. In this study, we found that COR inhibits early defense responses during nonhost disease resistance. Stomatal closure induced by a nonhost pathogen, P. syringae pv. tabaci, was disrupted by COR in tomato epidermal peels. In addition, nonhost HR cell death triggered by P. syringae pv. tabaci on tomato was remarkably delayed when COR was supplemented along with P. syringae pv. tabaci inoculation. Using isochorismate synthase (ICS-silenced tomato plants and transcript profiles of genes in SA- and JA-related defense pathways, we show that COR suppresses SA-mediated defense during nonhost resistance.

  4. Iron Prochelator BSIH Protects Retinal Pigment Epithelial Cells against Cell Death Induced by Hydrogen Peroxide

    OpenAIRE

    Charkoudian, Louise K.; Dentchev, Tzvete; Lukinova, Nina; Wolkow, Natalie; Dunaief, Joshua L.; Franz, Katherine J.

    2008-01-01

    Dysregulation of localized iron homeostasis is implicated in several degenerative diseases, including Parkinson’s, Alzheimer’s, and age-related macular degeneration, wherein iron-mediated oxidative stress is hypothesized to contribute to cell death. Inhibiting toxic iron without altering normal metal-dependent processes presents significant challenges for standard small molecule chelating agents. We previously introduced BSIH (isonicotinic acid [2-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl...

  5. A novel mechanism of murine hepatocyte death inducible by Concanavalin A

    OpenAIRE

    Leist, Marcel; Wendel, Albrecht

    1996-01-01

    Background: Concanavalin A (Con A) is a plant lectin that polyclonally activates T-cells. When given intravenously to mice it induces a selective liver failure. Hepatotoxicity following Con A administration involves the systemic release of tumor necrosis factor.Methods: We used primary murine hepatocyte cultures to investigate mechanisms of hepatocytotoxicity related to this animal model of inflammatory liver failure.Results: Con A was directly toxic for cultured hepatocytes. This toxicity di...

  6. Cell death induced by AC magnetic fields and magnetic nanoparticles: current state and perspectives.

    Science.gov (United States)

    Goya, Gerardo F; Asín, Laura; Ibarra, M Ricardo

    2013-12-01

    This review analyses the advances in the field of magnetically induced cell death using intracellular magnetic nanoparticles (MNPs). Emphasis has been given to in vitro research results, discussing the action of radiofrequency (RF) waves on biological systems as well as those results of thermally induced cell death in terms of MNP cell interactions. Our main goal has been to provide a unified depiction of many recent experiments and theoretical models relevant to the effect of applied electromagnetic fields on MNPs after cellular uptake and the cytotoxicity assessment of MNPs. We have addressed the effects of RF waves used for in vitro magnetic hyperthermia on eukaryotic cells regarding physical modifications of the cellular local environment and cell viability.

  7. Furan fatty acids efficiently rescue brain cells from cell death induced by oxidative stress

    NARCIS (Netherlands)

    Teixeira, A.; Cox, R.C.; Egmond, M.R.

    2013-01-01

    Treatment of rat brain C6 astroglioma cells with furan fatty acid F6 prior to exposure to hydrogen peroxide shows a strong protective effect of F6 against cell death resulting from oxidative stress. This protective effect is obtained only for F6 administered as a free fatty acid and with an intact f

  8. Hydrogen Peroxide Contributes to the Epithelial Cell Death Induced by the Oral Mitis Group of Streptococci

    OpenAIRE

    Okahashi, Nobuo; Sumitomo, Tomoko; Nakata, Masanobu; Sakurai, Atsuo; Kuwata, Hirotaka; Kawabata, Shigetada

    2014-01-01

    Members of the mitis group of streptococci are normal inhabitants of the commensal flora of the oral cavity and upper respiratory tract of humans. Some mitis group species, such as Streptococcus oralis and Streptococcus sanguinis, are primary colonizers of the human oral cavity. Recently, we found that hydrogen peroxide (H2O2) produced by S. oralis is cytotoxic to human macrophages, suggesting that streptococcus-derived H2O2 may act as a cytotoxin. Since epithelial cells provide a physical ba...

  9. Tumor cell death induced by the inhibition of mitochondrial electron transport: The effect of 3-hydroxybakuchiol

    Energy Technology Data Exchange (ETDEWEB)

    Jaña, Fabián [Clinical and Molecular Pharmacology Program, University of Chile, Santiago (Chile); Faini, Francesca [Department of Chemistry, Faculty of Sciences, University of Chile, Santiago (Chile); Lapier, Michel; Pavani, Mario [Clinical and Molecular Pharmacology Program, University of Chile, Santiago (Chile); Kemmerling, Ulrike [Anatomy and Developmental Biology Program, ICBM, Faculty of Medicine, University of Chile, Santiago (Chile); Morello, Antonio; Maya, Juan Diego; Jara, José [Clinical and Molecular Pharmacology Program, University of Chile, Santiago (Chile); Parra, Eduardo [Laboratory of Experimental Biomedicine, University of Tarapaca, Campus Esmeralda, Iquique (Chile); Ferreira, Jorge, E-mail: jferreir@med.uchile.cl [Clinical and Molecular Pharmacology Program, University of Chile, Santiago (Chile)

    2013-10-15

    Changes in mitochondrial ATP synthesis can affect the function of tumor cells due to the dependence of the first step of glycolysis on mitochondrial ATP. The oxidative phosphorylation (OXPHOS) system is responsible for the synthesis of approximately 90% of the ATP in normal cells and up to 50% in most glycolytic cancers; therefore, inhibition of the electron transport chain (ETC) emerges as an attractive therapeutic target. We studied the effect of a lipophilic isoprenylated catechol, 3-hydroxybakuchiol (3-OHbk), a putative ETC inhibitor isolated from Psoralea glandulosa. 3-OHbk exerted cytotoxic and anti-proliferative effects on the TA3/Ha mouse mammary adenocarcinoma cell line and induced a decrease in the mitochondrial transmembrane potential, the activation of caspase-3, the opening of the mitochondrial permeability transport pore (MPTP) and nuclear DNA fragmentation. Additionally, 3-OHbk inhibited oxygen consumption, an effect that was completely reversed by succinate (an electron donor for Complex II) and duroquinol (electron donor for Complex III), suggesting that 3-OHbk disrupted the electron flow at the level of Complex I. The inhibition of OXPHOS did not increase the level of reactive oxygen species (ROS) but caused a large decrease in the intracellular ATP level. ETC inhibitors have been shown to induce cell death through necrosis and apoptosis by increasing ROS generation. Nevertheless, we demonstrated that 3-OHbk inhibited the ETC and induced apoptosis through an interaction with Complex I. By delivering electrons directly to Complex III with duroquinol, cell death was almost completely abrogated. These results suggest that 3-OHbk has antitumor activity resulting from interactions with the ETC, a system that is already deficient in cancer cells. - Highlights: • We studied the anticancer activity of a natural compound, 3-OHbk, on TA3/Ha cells. • 3-OHbk inhibited mitochondrial electron flow by interacting with Complex I. • Complex I inhibition did not induce ROS generation. • 3-OHbk induced apoptosis in tumor cells with no effect on mammary epithelial cells. • Mitochondrial bioenergetics is implicated in anticancer action of 3-OHbk.

  10. p53 dependent apoptotic cell death induces embryonic malformation in Carassius auratus under chronic hypoxia.

    Directory of Open Access Journals (Sweden)

    Paramita Banerjee Sawant

    Full Text Available Hypoxia is a global phenomenon affecting recruitment as well as the embryonic development of aquatic fauna. The present study depicts hypoxia induced disruption of the intrinsic pathway of programmed cell death (PCD, leading to embryonic malformation in the goldfish, Carrasius auratus. Constant hypoxia induced the early expression of pro-apoptotic/tumor suppressor p53 and concomitant expression of the cell death molecule, caspase-3, leading to high level of DNA damage and cell death in hypoxic embryos, as compared to normoxic ones. As a result, the former showed delayed 4 and 64 celled stages and a delay in appearance of epiboly stage. Expression of p53 efficiently switched off expression of the anti-apoptotic Bcl-2 during the initial 12 hours post fertilization (hpf and caused embryonic cell death. However, after 12 hours, simultaneous downregulation of p53 and Caspase-3 and exponential increase of Bcl-2, caused uncontrolled cell proliferation and prevented essential programmed cell death (PCD, ultimately resulting in significant (p<0.05 embryonic malformation up to 144 hpf. Evidences suggest that uncontrolled cell proliferation after 12 hpf may have been due to downregulation of p53 abundance, which in turn has an influence on upregulation of anti-apoptotic Bcl-2. Therefore, we have been able to show for the first time and propose that hypoxia induced downregulation of p53 beyond 12 hpf, disrupts PCD and leads to failure in normal differentiation, causing malformation in gold fish embryos.

  11. Tualang Honey Promotes Apoptotic Cell Death Induced by Tamoxifen in Breast Cancer Cell Lines

    Directory of Open Access Journals (Sweden)

    Nik Soriani Yaacob

    2013-01-01

    Full Text Available Tualang honey (TH is rich in flavonoids and phenolic acids and has significant anticancer activity against breast cancer cells comparable to the effect of tamoxifen (TAM, in vitro. The current study evaluated the effects of TH when used in combination with TAM on MCF-7 and MDA-MB-231 cells. We observed that TH promoted the anticancer activity of TAM in both the estrogen receptor-(ER-responsive and ER-nonresponsive human breast cancer cell lines. Flow cytometric analyses indicated accelerated apoptosis especially in MDA-MB-231 cells and with the involvement of caspase-3/7, -8 and -9 activation as shown by fluorescence microscopy. Depolarization of the mitochondrial membrane was also increased in both cell lines when TH was used in combination with TAM compared to TAM treatment alone. TH may therefore be a potential adjuvant to be used with TAM for reducing the dose of TAM, hence, reducing TAM-induced adverse effects.

  12. Quorum Quenching Revisited—From Signal Decays to Signalling Confusion

    Directory of Open Access Journals (Sweden)

    Kok-Gan Chan

    2012-04-01

    Full Text Available In a polymicrobial community, while some bacteria are communicating with neighboring cells (quorum sensing, others are interrupting the communication (quorum quenching, thus creating a constant arms race between intercellular communication. In the past decade, numerous quorum quenching enzymes have been found and initially thought to inactivate the signalling molecules. Though this is widely accepted, the actual roles of these quorum quenching enzymes are now being uncovered. Recent evidence extends the role of quorum quenching to detoxification or metabolism of signalling molecules as food and energy source; this includes “signalling confusion”, a term coined in this paper to refer to the phenomenon of non-destructive modification of signalling molecules. While quorum quenching has been explored as a novel anti-infective therapy targeting, quorum sensing evidence begins to show the development of resistance against quorum quenching.

  13. An optical analog signal transmitter

    Energy Technology Data Exchange (ETDEWEB)

    Fudzita, K.; Itida, T.; Tanaka, Kh.

    1984-01-11

    An optical laser analog signal transmitter employing an amplitude modulated subcarrier is patented; this transmitter performs stable and high quality transmission of information signals over great distances. A feature of the proposed transmitter is a special transmitter operational mode in which the light emission reflected off the connection point to the fiber optic conduit is sent back to the laser diode in a transient period. As a result, the critical mode of the generated emission is not influenced by the reflected signal. The transmitter consists of a laser diode with biasing near the cutoff point, an amplitude modulator with a subcarrier frequency oscillator, a section of flexible fiber-optic cable of length L, which connects the laser diode to the primary optical fiber conduit, and the connector itself. The subcarrier frequency may vary over wide ranges to establish the necessary correlation between the length of the light conduit section L and the return propagation time of the reflected light signal from the connection point to the laser diode. The difference between the lasing time of the light signal and the return time to the laser diode of the signal reflected off the connector is determined by the relation tau equals 2nL/c - mtauc, where L is the length of the connecting section; n is the refractivity of the optical fiber; c is the velocity of light; tauc is the period of the high frequency subcarrier signal; and m is an integer.

  14. HIF-1α signaling activation by post-ischemia treatment with astragaloside IV attenuates myocardial ischemia-reperfusion injury.

    Directory of Open Access Journals (Sweden)

    Jingwen Si

    Full Text Available In this study, we evaluated the effect of astragaloside IV (Ast IV post-ischemia treatment on myocardial ischemia-reperfusion (IR injury (IRI. We also examined whether hypoxia inducible factor-1α (HIF-1α and its downstream gene-inducible nitric oxide (NO synthase (iNOS play roles in the cardioprotective effect of Ast IV. Cultured cardiomyocytes and perfused isolated rat hearts were exposed to Ast IV during reperfusion in the presence or absence of the HIF-1α inhibitor 2-methoxyestradiol (2-MeOE2. The post-ischemia treatment with Ast IV protected cardiomyocytes from the apoptosis and death induced by simulated IRI (SIRI. Additionally, in cardiomyocytes, 2-MeOE2 and HIF-1α siRNA treatment each not only abolished the anti-apoptotic effect of post-ischemia treatment with Ast IV but also reversed the upregulation of HIF-1α and iNOS expression. Furthermore, after treatment with Ast IV, post-ischemic cardiac functional recovery and lactate dehydrogenase (LDH release in the coronary flow (CF were improved, and the myocardial infarct size was decreased. Moreover, the number of apoptotic cells was reduced, and the upregulation of the anti-apoptotic protein Bcl2 and downregulation of the pro-apoptotic protein Caspase3 were reversed. 2-MeOE2 reversed these effects of Ast IV on IR-injured hearts. These results suggest that post-ischemia treatment with Ast IV can attenuate IRI by upregulating HIF-1α expression, which transmits a survival signal to the myocardium.

  15. Signalling among relatives. I. Is costly signalling too costly?

    OpenAIRE

    Bergstrom, C. T.; Lachmann, M.

    1997-01-01

    Zahavi's handicap principle,originally proposed as an explanation for sexual selection ofelaborate male traits, suggests that a sufficient cost to dishonest signals can outweigh the rewards of deception and allow individuals to communicate honestly. Maynard Smith (1991) and Johnstone and Grafen (1992) introduce the Sir Philip Sidney game in order to extend the handicap principle to interactions among related individuals, and to demonstrate that stable costly signalling systems can exist among...

  16. Wnt signaling in cardiovascular physiology.

    Science.gov (United States)

    Marinou, K; Christodoulides, C; Antoniades, C; Koutsilieris, M

    2012-12-01

    Wnt signaling pathways play a key role in cardiac development, angiogenesis, and cardiac hypertrophy; emerging evidence suggests that they are also involved in the pathophysiology of atherosclerosis. Specifically, an important role for Wnts has been described in the regulation of endothelial inflammation, vascular calcification, and mesenchymal stem cell differentiation. Wnt signaling also induces monocyte adhesion to endothelial cells and is crucial for the regulation of vascular smooth-muscle cell (VSMC) behavior. We discuss how the Wnt pathways are implicated in vascular biology and outline the role of Wnt signaling in atherosclerosis. Dissecting Wnt pathways involved in atherogenesis and cardiovascular disease may provide crucial insights into novel mechanisms with therapeutic potential for atherosclerosis.

  17. On Generalized Fractional Differentiator Signals

    Directory of Open Access Journals (Sweden)

    Hamid A. Jalab

    2013-01-01

    Full Text Available By employing the generalized fractional differential operator, we introduce a system of fractional order derivative for a uniformly sampled polynomial signal. The calculation of the bring in signal depends on the additive combination of the weighted bring-in of N cascaded digital differentiators. The weights are imposed in a closed formula containing the Stirling numbers of the first kind. The approach taken in this work is to consider that signal function in terms of Newton series. The convergence of the system to a fractional time differentiator is discussed.

  18. The IRS-1 signaling system.

    Science.gov (United States)

    White, M F

    1994-02-01

    IRS-1 is a principal substrate of the insulin receptor tyrosine kinase. It undergoes multi-site tyrosine phosphorylation and mediates the insulin signal by associating with various signaling molecules containing Src homology 2 domains. Interleukin-4 also stimulates IRS-1 phosphorylation, and it is suspected that a few more growth factors or cytokines will be added to form a select group of receptors that utilize the IRS-1 signaling pathway. More IRS-1-like adapter molecules, such as 4PS (IRS-2), may remain to be found.

  19. Queen signaling in social wasps

    DEFF Research Database (Denmark)

    van Zweden, Jelle Stijn; Bonckaert, Wim; Wenseleers, Tom;

    2014-01-01

    sterile (queen control), or if instead queens honestly signal their fertility and workers reproduce according to their own evolutionary incentives (queen signaling). Here, we test these competing hypotheses using data from Vespine wasps. We show that in natural colonies of the Saxon wasp, Dolichovespula...... saxonica, queens emit reliable chemical cues of their true fertility and that these putative queen signals decrease as the colony develops and worker reproduction increases. Moreover, these putative pheromones of D. saxonica show significant conservation with those of Vespula vulgaris and other Vespinae...

  20. Jasmonate Signal Pathway in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Xiao-Yi Shan; Zhi-Long Wang; Daoxin Xie

    2007-01-01

    Jasmonates (JAs), which include jasmonic acid and its cyclopentane derivatives are synthesized from the octadecanoid pathway and widely distributed throughout the plant kingdom. JAs modulate the expression of numerous genes and mediate responses to stress, wounding, insect attack, pathogen infection, and UV damage. They also affect a variety of processes in many plant developmental processes. The JA signal pathway involves two important events: the biosynthesis of JA and the transduction of JA signal. Several important Arabidopsis mutants in jasmonate signal pathway were described in this review.

  1. Smoke Signal or Smoke Screen?

    DEFF Research Database (Denmark)

    Vergne, Jean-Philippe; Wernicke, Georg; Brenner, Steffen

    disapproval, whereas ambiguous signals represent a form of category straddling that attenuates disapproval. We find empirical support for this proposition in the context of CEO overcompensation in the U.S. (1995-2007) after examining two organizational signals that affect perceptions of economic fairness (i.......e. corporate philanthropy) and social fairness (i.e. employee diversity). Our integration of the signaling and categorization literatures adds to extant knowledge on firm’s social evaluations and recasts CEO compensation research within the literature on information intermediaries....

  2. Statistical theory of signal detection

    CERN Document Server

    Helstrom, Carl Wilhelm; Costrell, L; Kandiah, K

    1968-01-01

    Statistical Theory of Signal Detection, Second Edition provides an elementary introduction to the theory of statistical testing of hypotheses that is related to the detection of signals in radar and communications technology. This book presents a comprehensive survey of digital communication systems. Organized into 11 chapters, this edition begins with an overview of the theory of signal detection and the typical detection problem. This text then examines the goals of the detection system, which are defined through an analogy with the testing of statistical hypotheses. Other chapters consider

  3. GA signalling and cross-talk with other signalling pathways.

    Science.gov (United States)

    Lor, Vai S; Olszewski, Neil E

    2015-01-01

    Gibberellins (GAs) are phytohormones that regulate growth and development. DELLA proteins repress GA responses. GA binding to its receptor triggers a series of events that culminate in the destruction of DELLA proteins by the 26S proteasome, which removes the repression of GA signalling. DELLA proteins are transcription co-activators that induce the expression of genes which encode products that inhibit GA responses. In addition to repressing GA responses, DELLA proteins influence the activity of other signalling pathways and serve as a central hub from which other pathways influence GA signalling. In this role, DELLA proteins bind to and inhibit proteins, including transcription factors that act in the signalling pathways of other hormones and light. The binding of these proteins to DELLA proteins also inhibits DELLA activity. GA signalling is subject to homoeostatic regulation through GA-induced repression of GA biosynthesis gene expression, and increased production of the GA receptor and enzymes that catabolize bioactive GAs. This review also discusses the nature of mutant DELLA alleles that are used to produce high-yielding 'Green Revolution' cereal varieties, and highlights important gaps in our knowledge of GA signalling. PMID:26374886

  4. Signal processing with free software practical experiments

    CERN Document Server

    Auger, François

    2014-01-01

    An ideal resource for students, industrial engineers, and researchers, Signal Processing with Free Software Practical Experiments presents practical experiments in signal processing using free software. The text introduces elementary signals through elementary waveform, signal storage files and elementary operations on signals and then presents the first tools to signal analysis such as temporal and frequency characteristics leading to Time-frequency analysis. Non-parametric spectral analysis is also discussed as well as signal processing through sampling, resampling, quantification, an

  5. Extracellular modulators of Wnt signalling.

    Science.gov (United States)

    Malinauskas, Tomas; Jones, E Yvonne

    2014-12-01

    Wnt morphogens are secreted signalling proteins that play leading roles in embryogenesis and tissue homeostasis throughout life. Wnt signalling is controlled by multiple mechanisms, including posttranslational modification of Wnts, antagonist binding (to Wnts or their receptors), and regulation of the availability of Wnt receptors. Recent crystallographic, structure-guided biophysical and cell-based studies have advanced our understanding of how Wnt signalling is regulated at the cell surface. Structures include Wnt in complex with the cysteine-rich domain (CRD) of Frizzled, extracellular fragments of Wnt co-receptor LRP6, LRP6-binding antagonists Dickkopf and Sclerostin, antagonists 5T4/WAIF1 and Wnt inhibitory factor 1 (WIF-1), as well as Frizzled-ubiquitin ligases ZNRF3/RNF43 (in isolation and in complexes with Wnt signalling promoters R-spondins and LGR5). We review recent discoveries and remaining questions. PMID:25460271

  6. Nuclear Receptor Signaling Atlas (NURSA)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Nuclear Receptor Signaling Atlas (NURSA) is designed to foster the development of a comprehensive understanding of the structure, function, and role in disease...

  7. Discretization of Parametrizable Signal Manifolds

    CERN Document Server

    Vural, Elif; 10.1109/TIP.2011.2155077

    2011-01-01

    Transformation-invariant analysis of signals often requires the computation of the distance from a test pattern to a transformation manifold. In particular, the estimation of the distances between a transformed query signal and several transformation manifolds representing different classes provides essential information for the classification of the signal. In many applications the computation of the exact distance to the manifold is costly, whereas an efficient practical solution is the approximation of the manifold distance with the aid of a manifold grid. In this paper, we consider a setting with transformation manifolds of known parameterization. We first present an algorithm for the selection of samples from a single manifold that permits to minimize the average error in the manifold distance estimation. Then we propose a method for the joint discretization of multiple manifolds that represent different signal classes, where we optimize the transformation-invariant classification accuracy yielded by the...

  8. Pub: Grid 2004, 2 signalement

    DEFF Research Database (Denmark)

    2004-01-01

    2. signalement er en af flere manifesteringer omkring det at skabe en tale omkring udfordringer. Pub: Grid 2004 indeholder en række arbejder, der afspejler et fagligt udviklingsarbejde på afdeling 6....

  9. Signal processing for semiconductor detectors

    International Nuclear Information System (INIS)

    A balanced perspective is provided on the processing of signals produced by semiconductor detectors. The general problems of pulse shaping to optimize resolution with constraints imposed by noise, counting rate and rise time fluctuations are discussed

  10. Sounds, signals and space maps

    OpenAIRE

    Carr, Catherine

    2002-01-01

    The auditory system transforms information from one frame of reference into another to create a map of space in the brain. The source of a visual signal that guides this transformation in barn owls has now been found.

  11. Aberrant Wnt Signaling in Leukemia.

    Science.gov (United States)

    Staal, Frank J T; Famili, Farbod; Garcia Perez, Laura; Pike-Overzet, Karin

    2016-01-01

    The Wnt signaling pathway is essential in the development and homeostasis of blood and immune cells, but its exact role is still controversial and is the subject of intense research. The malignant counterpart of normal hematopoietic cells, leukemic (stem) cells, have hijacked the Wnt pathway for their self-renewal and proliferation. Here we review the multiple ways dysregulated Wnt signaling can contribute to leukemogenesis, both cell autonomously as well as by changes in the microenvironment. PMID:27571104

  12. Python for audio signal processing

    OpenAIRE

    Glover, John C.; Lazzarini, Victor; Timoney, Joseph

    2011-01-01

    This paper discusses the use of Python for developing audio signal processing applications. Overviews of Python language, NumPy, SciPy and Matplotlib are given, which together form a powerful platform for scientic computing. We then show how SciPy was used to create two audio programming libraries, and describe ways that Python can be integrated with the SndObj library and Pure Data, two existing environments for music composition and signal processing.

  13. Apoptotic Signaling in Mouse Odontogenesis

    OpenAIRE

    Matalova, Eva; Svandova, Eva; Tucker, Abigail S.

    2012-01-01

    Apoptosis is an important morphogenetic event in embryogenesis as well as during postnatal life. In the last 2 decades, apoptosis in tooth development (odontogenesis) has been investigated with gradually increasing focus on the mechanisms and signaling pathways involved. The molecular machinery responsible for apoptosis exhibits a high degree of conservation but also organ and tissue specific patterns. This review aims to discuss recent knowledge about apoptotic signaling networks during odon...

  14. Handbook of signal processing systems

    CERN Document Server

    Deprettere, Ed; Leupers, Rainer; Takala, Jarmo

    2013-01-01

    Handbook of Signal Processing Systems is organized in three parts. The first part motivates representative applications that drive and apply state-of-the art methods for design and implementation of signal processing systems; the second part discusses architectures for implementing these applications; the third part focuses on compilers and simulation tools, describes models of computation and their associated design tools and methodologies. This handbook is an essential tool for professionals in many fields and researchers of all levels.

  15. Sentiment analysis for PTSD signals

    CERN Document Server

    Kagan, Vadim; Sapounas, Demetrios

    2013-01-01

    This book describes a computational framework for real-time detection of psychological signals related to Post-Traumatic Stress Disorder (PTSD) in online text-based posts, including blogs and web forums. Further, it explores how emerging computational techniques such as sentiment mining can be used in real-time to identify posts that contain PTSD-related signals, flag those posts, and bring them to the attention of psychologists, thus providing an automated flag and referral capability.

  16. Insulin Signaling and Heart Failure.

    Science.gov (United States)

    Riehle, Christian; Abel, E Dale

    2016-04-01

    Heart failure is associated with generalized insulin resistance. Moreover, insulin-resistant states such as type 2 diabetes mellitus and obesity increases the risk of heart failure even after adjusting for traditional risk factors. Insulin resistance or type 2 diabetes mellitus alters the systemic and neurohumoral milieu, leading to changes in metabolism and signaling pathways in the heart that may contribute to myocardial dysfunction. In addition, changes in insulin signaling within cardiomyocytes develop in the failing heart. The changes range from activation of proximal insulin signaling pathways that may contribute to adverse left ventricular remodeling and mitochondrial dysfunction to repression of distal elements of insulin signaling pathways such as forkhead box O transcriptional signaling or glucose transport, which may also impair cardiac metabolism, structure, and function. This article will review the complexities of insulin signaling within the myocardium and ways in which these pathways are altered in heart failure or in conditions associated with generalized insulin resistance. The implications of these changes for therapeutic approaches to treating or preventing heart failure will be discussed.

  17. Systemic defense signaling in tomato

    Institute of Scientific and Technical Information of China (English)

    LI Changbao; SUN Jiaqiang; JIANG Hongling; WU Xiaoyan; LI Chuanyou

    2005-01-01

    The wound-inducible expression of proteinase inhibitors (PIs) genes in tomato provides a powerful model system to elucidate the signal transduction pathway of sys- temic defense response. An increasing body of evidence indi- cates that systemin and jasmonic acid (JA) work in the same signaling pathway to activate the expression of PIs and other defense-related genes. However, little is known about how systemin and JA interact to regulate cell to cell communica- tion over long distances. Genetic analysis of the systemin/JA signaling pathway in tomato plants provides a unique opportunity to dissect the mechanism by which peptide and oxylipin signals interact to coordinate systemic expression of defense-related genes. Previously, it has been proposed that systemin is the long-distance mobile signal for systemic expression of defense related genes. However, recent genetic approach provided new evidence that jasmonic acid, rather than systemin, functions as the systemic wound signal, and that the peptide systemin works to regulate the biosynthesis of JA.

  18. SignalPlant: an open signal processing software platform.

    Science.gov (United States)

    Plesinger, F; Jurco, J; Halamek, J; Jurak, P

    2016-07-01

    The growing technical standard of acquisition systems allows the acquisition of large records, often reaching gigabytes or more in size as is the case with whole-day electroencephalograph (EEG) recordings, for example. Although current 64-bit software for signal processing is able to process (e.g. filter, analyze, etc) such data, visual inspection and labeling will probably suffer from rather long latency during the rendering of large portions of recorded signals. For this reason, we have developed SignalPlant-a stand-alone application for signal inspection, labeling and processing. The main motivation was to supply investigators with a tool allowing fast and interactive work with large multichannel records produced by EEG, electrocardiograph and similar devices. The rendering latency was compared with EEGLAB and proves significantly faster when displaying an image from a large number of samples (e.g. 163-times faster for 75  ×  10(6) samples). The presented SignalPlant software is available free and does not depend on any other computation software. Furthermore, it can be extended with plugins by third parties ensuring its adaptability to future research tasks and new data formats.

  19. SignalPlant: an open signal processing software platform.

    Science.gov (United States)

    Plesinger, F; Jurco, J; Halamek, J; Jurak, P

    2016-07-01

    The growing technical standard of acquisition systems allows the acquisition of large records, often reaching gigabytes or more in size as is the case with whole-day electroencephalograph (EEG) recordings, for example. Although current 64-bit software for signal processing is able to process (e.g. filter, analyze, etc) such data, visual inspection and labeling will probably suffer from rather long latency during the rendering of large portions of recorded signals. For this reason, we have developed SignalPlant-a stand-alone application for signal inspection, labeling and processing. The main motivation was to supply investigators with a tool allowing fast and interactive work with large multichannel records produced by EEG, electrocardiograph and similar devices. The rendering latency was compared with EEGLAB and proves significantly faster when displaying an image from a large number of samples (e.g. 163-times faster for 75  ×  10(6) samples). The presented SignalPlant software is available free and does not depend on any other computation software. Furthermore, it can be extended with plugins by third parties ensuring its adaptability to future research tasks and new data formats. PMID:27243208

  20. Proteolytic activation of proapoptotic kinase protein kinase Cδ by tumor necrosis factor α death receptor signaling in dopaminergic neurons during neuroinflammation

    Directory of Open Access Journals (Sweden)

    Gordon Richard

    2012-04-01

    neuroinflammatory LPS model was also observed. Conclusions Collectively, these results identify proteolytic activation of PKCδ proapoptotic signaling as a key downstream effector of dopaminergic cell death induced by TNF. These findings also provide a rationale for therapeutically targeting PKCδ to mitigate progressive dopaminergic degeneration resulting from chronic neuroinflammatory processes.

  1. Calcium signaling in taste cells.

    Science.gov (United States)

    Medler, Kathryn F

    2015-09-01

    The sense of taste is a common ability shared by all organisms and is used to detect nutrients as well as potentially harmful compounds. Thus taste is critical to survival. Despite its importance, surprisingly little is known about the mechanisms generating and regulating responses to taste stimuli. All taste responses depend on calcium signals to generate appropriate responses which are relayed to the brain. Some taste cells have conventional synapses and rely on calcium influx through voltage-gated calcium channels. Other taste cells lack these synapses and depend on calcium release to formulate an output signal through a hemichannel. Beyond establishing these characteristics, few studies have focused on understanding how these calcium signals are formed. We identified multiple calcium clearance mechanisms that regulate calcium levels in taste cells as well as a calcium influx that contributes to maintaining appropriate calcium homeostasis in these cells. Multiple factors regulate the evoked taste signals with varying roles in different cell populations. Clearly, calcium signaling is a dynamic process in taste cells and is more complex than has previously been appreciated. This article is part of a Special Issue entitled: 13th European Symposium on Calcium.

  2. Polarization signals in mantis shrimps

    Science.gov (United States)

    Cronin, Thomas W.; Chiou, Tsyr-Huei; Caldwell, Roy L.; Roberts, Nicholas; Marshall, Justin

    2009-08-01

    While color signals are well known as a form of animal communication, a number of animals communicate using signals based on patterns of polarized light reflected from specialized body parts or structures. Mantis shrimps, a group of marine crustaceans, have evolved a great diversity of such signals, several of which are based on photonic structures. These include resonant scattering devices, structures based on layered dichroic molecules, and structures that use birefringent layers to produce circular polarization. Such biological polarizers operate in different spectral regions ranging from the near-UV to medium wavelengths of visible light. In addition to the structures that are specialized for signal production, the eyes of many species of mantis shrimp are adapted to detect linearly polarized light in the ultraviolet and in the green, using specialized sets of photoreceptors with oriented, dichroic visual pigments. Finally, a few mantis shrimp species produce biophotonic retarders within their photoreceptors that permit the detection of circularly polarized light and are thus the only animals known to sense this form of polarization. Mantis shrimps use polarized light in species-specific signals related to mating and territorial defense, and their means of manipulating light's polarization can inspire designs for artificial polarizers and achromatic retarders.

  3. Applied signal processing concepts, circuits, and systems

    CERN Document Server

    Hamdy, Nadder

    2008-01-01

    Introduction What are Signals? Signal parameters Why Signal processing? Analog vs. Digital Signal processing Practical Signal processing Systems Analog Signal Processing Amplitude Shaping Frequency Spectrum Shaping Phase Errors Correction Waveform Generation Analog Filter Design Describing Equations Design Procedures Filter Specifications Approximations to the Ideal Response Realization Practical RC-Filters Design Switched Capacitor Filter Realization Design examples Data Converters Introduction A typical DSP System Specifications of Data Converters Sampling Samp

  4. Optical time-lens signal processing

    DEFF Research Database (Denmark)

    Oxenløwe, Leif Katsuo; Galili, Michael; Mulvad, Hans Christian Hansen;

    2014-01-01

    This paper describes the use of optical time lenses for optical signal processing of advanced optical data signals. Examples given include 1.28 Tbaud Nyquist channel serial-to-parallel conversion and spectral magnification of OFDM signals.......This paper describes the use of optical time lenses for optical signal processing of advanced optical data signals. Examples given include 1.28 Tbaud Nyquist channel serial-to-parallel conversion and spectral magnification of OFDM signals....

  5. Mathematical model for classification of EEG signals

    Science.gov (United States)

    Ortiz, Victor H.; Tapia, Juan J.

    2015-09-01

    A mathematical model to filter and classify brain signals from a brain machine interface is developed. The mathematical model classifies the signals from the different lobes of the brain to differentiate the signals: alpha, beta, gamma and theta, besides the signals from vision, speech, and orientation. The model to develop further eliminates noise signals that occur in the process of signal acquisition. This mathematical model can be used on different platforms interfaces for rehabilitation of physically handicapped persons.

  6. Sparse Signal Recovery in Hilbert Spaces

    CERN Document Server

    Pope, Graeme

    2012-01-01

    This paper reports an effort to consolidate numerous coherence-based sparse signal recovery results available in the literature. We present a single theory that applies to general Hilbert spaces with the sparsity of a signal defined as the number of (possibly infinite-dimensional) subspaces participating in the signal's representation. Our general results recover uncertainty relations and coherence-based recovery thresholds for sparse signals, block-sparse signals, multi-band signals, signals in shift-invariant spaces, and signals in finite unions of (possibly infinite-dimensional) subspaces. Moreover, we improve upon and generalize several of the existing results and, in many cases, we find shortened and simplified proofs.

  7. The Dynamics of Costly Signaling

    Directory of Open Access Journals (Sweden)

    Elliott O. Wagner

    2013-04-01

    Full Text Available Costly signaling is a mechanism through which the honesty of signals can be secured in equilibrium, even in interactions where communicators have conflicting interests. This paper explores the dynamics of one such signaling game: Spence’s model of education. It is found that separating equilibria are unlikely to emerge under either the replicator or best response dynamics, but that partially communicative mixed equilibria are quite important dynamically. These mixtures are Lyapunov stable in the replicator dynamic and asymptotically stable in the best response dynamic. Moreover, they have large basins of attraction, in fact larger than those of either pooling or separating equilibria. This suggests that these mixtures may play significant, and underappreciated, roles in the explanation of the emergence and stability of information transfer.

  8. Multichannel Coding of Applause Signals

    Directory of Open Access Journals (Sweden)

    Jeroen Breebaart

    2007-08-01

    Full Text Available We develop a parametric multichannel audio codec dedicated to coding signals consisting of a dense series of transient-type events. These signals of which applause is a typical example are known to be problematic for such audio codecs. The codec design is based on preservation of both timbre and transient-type event density. It combines a very low complexity and a low parameter bit rate (0.2 kbps. In a formal listening test, we compared the proposed codec to the recently standardised MPEG Surround multichannel codec, with an associated parameter bit rate of 9 kbps. We found the new codec to have a significantly higher audio quality than the MPEG Surround codec for the two multichannel applause signals under test. Though this seems promising, the technique presented is not fully mature, for example, because issues related to integration of the proposed codec in the MPEG Surround codec were not addressed.

  9. Low power digital signal processing

    DEFF Research Database (Denmark)

    Paker, Ozgun

    2003-01-01

    This thesis introduces a novel approach to programmable and low power platform design for audio signal processing, in particular hearing aids. The proposed programmable platform is a heterogeneous multiprocessor architecture consisting of small and simple instruction set processors called mini...... data addressing capabilities lead to the design of low power mini-cores. The algorithm suite also consisted of less demanding and/or irregular algorithms (LMS, compression) that required subsample rate signal processing justifying the use of a DSP/CPU-core. The thesis also contributes to the recent...... to be a viable alternative to conventional expensive test equipment. Finally, the work presented in this thesis has been published at several IEEE workshops and conferences, and in the Journal of VLSI Signal Processing....

  10. Ocean circulation generated magnetic signals

    DEFF Research Database (Denmark)

    Manoj, C.; Kuvshinov, A.; Maus, S.;

    2006-01-01

    Conducting ocean water, as it flows through the Earth's magnetic field, generates secondary electric and magnetic fields. An assessment of the ocean-generated magnetic fields and their detectability may be of importance for geomagnetism and oceanography. Motivated by the clear identification...... of ocean tidal signatures in the CHAMP magnetic field data we estimate the ocean magnetic signals of steady flow using a global 3-D EM numerical solution. The required velocity data are from the ECCO ocean circulation experiment and alternatively from the OCCAM model for higher resolution. We assume...... of the magnetic field, as compared to the ECCO simulation. Besides the expected signatures of the global circulation patterns, we find significant seasonal variability of ocean magnetic signals in the Indian and Western Pacific Oceans. Compared to seasonal variation, interannual variations produce weaker signals....

  11. Purinergic signalling: an experimental perspective.

    Science.gov (United States)

    Housley, G D; Thorne, P R

    2000-07-01

    Investigation of the multiple roles of extracellular nucleotides in the cochlea has developed from analysis of ATP-activated conductances in single sensory hair cells. Molecular probes such as radiolabelled ATP analogues and radiolabelled mRNA for ATP-gated ion channel subunits (P2X receptors) rapidly revealed the extensive nature of ATP signalling in this sensory organ. This has provided a foundation for physiological investigations which put extracellular nucleotides at the centre of homeostatic regulation of the driving force for sound transduction, modulation of mechanical tuning, control of cochlear blood flow and auditory neurotransmission. The purinergic signal transduction pathways associated with these processes have several novel features of significance to the broader field of purinergic neuroscience. In turn, these studies have benefited from the recent experimental advances in the field of purinergic signalling, a significant component of which is associated with the work of Professor Geoffrey Burnstock.

  12. Signal processing and linear systems

    CERN Document Server

    Lathi, B P

    1998-01-01

    This text presents a comprehensive treatment of signal processing and linear systems suitable for juniors and seniors in electrical engineering. Based on B. P. Lathi's widely used book, Linear Systems and Signals, it features additional applications to communications, controls, and filtering as well as new chapters on analog and digital filters and digital signal processing. Lathi emphasizes the physical appreciation of concepts rather than the mere mathematical manipulation of symbols. Avoiding the tendency to treat engineering as a branch of applied mathematics, he uses mathematics to enhance physical and intuitive understanding of concepts, instead of employing it only to prove axiomatic theory. Theoretical results are supported by carefully chosen examples and analogies, allowing students to intuitively discover meaning for themselves.

  13. Notch Signaling and Brain Tumors

    DEFF Research Database (Denmark)

    Stockhausen, Marie; Kristoffersen, Karina; Poulsen, Hans Skovgaard

    2011-01-01

    Human brain tumors are a heterogenous group of neoplasms occurring inside the cranium and the central spinal cord. In adults and children, astrocytic glioma and medulloblastoma are the most common subtypes of primary brain tumors. These tumor types are thought to arise from cells in which Notch...... signaling plays a fundamental role during development. Recent findings have shown that Notch signaling is dysregulated, and contributes to the malignant potential of these tumors. Growing evidence point towards an important role for cancer stem cells in the initiation and maintenance of glioma...... and medulloblastoma. In this chapter we will cover the present findings of Notch signaling in human glioma and medulloblastoma and try to create an overall picture of its relevance in the pathogenesis of these tumors....

  14. Acoustically-Induced Electrical Signals

    Science.gov (United States)

    Brown, S. R.

    2014-12-01

    We have observed electrical signals excited by and moving along with an acoustic pulse propagating in a sandstone sample. Using resonance we are now studying the characteristics of this acousto-electric signal and determining its origin and the controlling physical parameters. Four rock samples with a range of porosities, permeabilities, and mineralogies were chosen: Berea, Boise, and Colton sandstones and Austin Chalk. Pore water salinity was varied from deionized water to sea water. Ag-AgCl electrodes were attached to the sample and were interfaced to a 4-wire electrical resistivity system. Under computer control, the acoustic signals were excited and the electrical response was recorded. We see strong acoustically-induced electrical signals in all samples, with the magnitude of the effect for each rock getting stronger as we move from the 1st to the 3rd harmonics in resonance. Given a particular fluid salinity, each rock has its own distinct sensitivity in the induced electrical effect. For example at the 2nd harmonic, Berea Sandstone produces the largest electrical signal per acoustic power input even though Austin Chalk and Boise Sandstone tend to resonate with much larger amplitudes at the same harmonic. Two effects are potentially responsible for this acoustically-induced electrical response: one the co-seismic seismo-electric effect and the other a strain-induced resistivity change known as the acousto-electric effect. We have designed experimental tests to separate these mechanisms. The tests show that the seismo-electric effect is dominant in our studies. We note that these experiments are in a fluid viscosity dominated seismo-electric regime, leading to a simple interpretation of the signals where the electric potential developed is proportional to the local acceleration of the rock. Toward a test of this theory we have measured the local time-varying acoustic strain in our samples using a laser vibrometer.

  15. Myxoma Virus Leukemia-Associated Protein Is Responsible for Major Histocompatibility Complex Class I and Fas-CD95 Down-Regulation and Defines Scrapins, a New Group of Surface Cellular Receptor Abductor Proteins

    OpenAIRE

    Guerin, Jean-Luc; Gelfi, Jacqueline; Boullier, Severine; Delverdier, Maxence; Bellanger, Frederique-Anne; Bertagnoli, Stephane; Drexler, Ingo; Sutter, Gerd; Messud-Petit, Frederique

    2002-01-01

    Down-modulation of major histocompatibility class I (MHC-I) molecules is a viral strategy for survival in the host. Myxoma virus, a member of the Poxviridae family responsible for rabbit myxomatosis, can down-modulate the expression of MHC-I molecules, but the viral factor(s) has not been described. We cloned and characterized a gene coding for an endoplasmic reticulum (ER)-resident protein containing an atypical zinc finger and two transmembrane domains, which we called myxoma virus leukemia...

  16. High expression of CD40 on B-cell precursor acute lymphoblastic leukemia blasts is an independent risk factor associated with improved survival and enhanced capacity to up-regulate the death receptor CD95

    NARCIS (Netherlands)

    A. Troeger (Anja); L. Glouchkova (Ludmila); B. Ackermann (Birgit); G. Escherich (Gabriele); R. Meisel (Roland); H. Hanenberg (Helmut); M.L. den Boer (Monique); R. Pieters (Rob); G.E. Janka-Schaub (Gritta); U. Goebel (Ulrich); H.J. Laws; D. Dilloo (Dagmar)

    2008-01-01

    textabstractCD40 and CD27, members of the tumor necrosis factor receptor (TNFR) family, are critical regulators of lymphocyte growth and differentiation. In B-cell precursor acute lymphoblastic leukemia (BCP-ALL), we prospectively assessed the impact of CD40 and CD27 on outcome in 121 children treat

  17. Purinergic signaling at immunological synapses.

    Science.gov (United States)

    Dubyak, G R

    2000-07-01

    The early studies and hypotheses of Geoffrey Burnstock catalyzed intensive characterization of roles for nucleotides and P2 nucleotide receptors in neurotransmission and neuromodulation. These latter analyses have focused on the mechanisms of nucleotide release and action in the microenvironments of nerve endings and synapses. However, studies of various white blood cells, such as monocytes, neutrophils, and lymphocytes, suggest that locally released nucleotides also modulate intercellular signaling at so-called 'immunological synapses'. This communication describes recent findings and speculations regarding nucleotide release and signaling in several key phases of the immune and inflammatory responses.

  18. Signal processing for cognitive radios

    CERN Document Server

    Jayaweera, Sudharman K

    2014-01-01

    This book covers power electronics, in depth, by presenting the basic principles and application details, and it can be used both as a textbook and reference book.  Introduces the specific type of CR that has gained the most research attention in recent years: the CR for Dynamic Spectrum Access (DSA). Provides signal processing solutions to each task by relating the tasks to materials covered in Part II. Specialized chapters then discuss specific signal processing algorithms required for DSA and DSS cognitive radios  

  19. Chaotic signals in digital communications

    CERN Document Server

    Eisencraft, Marcio; Suyama, Ricardo

    2013-01-01

    Chaotic Signals in Digital Communications combines fundamental background knowledge with state-of-the-art methods for using chaotic signals and systems in digital communications. The book builds a bridge between theoretical works and practical implementation to help researchers attain consistent performance in realistic environments. It shows the possible shortcomings of the chaos-based communication systems proposed in the literature, particularly when they are subjected to non-ideal conditions. It also presents a toolbox of techniques for researchers working to actually implement such system

  20. Signal processing for remote sensing

    CERN Document Server

    Chen, CH

    2007-01-01

    Written by leaders in the field, Signal Processing for Remote Sensing explores the data acquisitions segment of remote sensing. Each chapter presents a major research result or the most up to date development of a topic. The book includes a chapter by Dr. Norden Huang, inventor of the Huang-Hilbert transform who, along with and Dr. Steven Long discusses the application of the transform to remote sensing problems. It also contains a chapter by Dr. Enders A. Robinson, who has made major contributions to seismic signal processing for over half a century, on the basic problem of constructing seism

  1. Genomic Signals of Reoriented ORFs

    Directory of Open Access Journals (Sweden)

    Paul Dan Cristea

    2004-01-01

    Full Text Available Complex representation of nucleotides is used to convert DNA sequences into complex digital genomic signals. The analysis of the cumulated phase and unwrapped phase of DNA genomic signals reveals large-scale features of eukaryote and prokaryote chromosomes that result from statistical regularities of base and base-pair distributions along DNA strands. By reorienting the chromosome coding regions, a “hidden” linear variation of the cumulated phase has been revealed, along with the conspicuous almost linear variation of the unwrapped phase. A model of chromosome longitudinal structure is inferred on these bases.

  2. DMPD: Signal integration between IFNgamma and TLR signalling pathways in macrophages. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 16920490 Signal integration between IFNgamma and TLR signalling pathways in macroph...tml) (.csml) Show Signal integration between IFNgamma and TLR signalling pathways in macrophages. PubmedID 1...6920490 Title Signal integration between IFNgamma and TLR signalling pathways in

  3. VLSI mixed signal processing system

    Science.gov (United States)

    Alvarez, A.; Premkumar, A. B.

    1993-01-01

    An economical and efficient VLSI implementation of a mixed signal processing system (MSP) is presented in this paper. The MSP concept is investigated and the functional blocks of the proposed MSP are described. The requirements of each of the blocks are discussed in detail. A sample application using active acoustic cancellation technique is described to demonstrate the power of the MSP approach.

  4. The Signaling Theory of Symptoms

    Directory of Open Access Journals (Sweden)

    Leander Steinkopf

    2015-08-01

    Full Text Available Placebo research shows that the subjective quality of care and social support, as well as the patients’ expectations of treatment, influence therapeutic outcomes. However, this phenomenon, known as the placebo effect, does not usually cure the disease, but rather can provide symptomatic relief: It may soothe symptoms such as pain, swelling, or nausea that constitute part of an immune response. The function of this mechanism remains unclear. This article puts forward the Signaling Theory of Symptoms (STS as a possible explanation. According to STS, discernible aspects of an immune response, such as pain, swelling, or nausea, not only serve a defensive and healing function but also a signaling function: symptoms signal the need for care and treatment to potential helpers. Once help and treatment are granted, the signaling function is fulfilled and the symptoms diminish. This mechanism may have been a significant advantage in preindustrial environments, when sufferers depended on extensive social support and personal treatment. Nowadays, from the point of view of modern materialist medicine, the mobilization of social support no longer seems so crucial, and thus the placebo effect has been assigned a somewhat mysterious quality.

  5. Handbook of signal processing systems

    CERN Document Server

    Bhattacharyya, Shuvra S; Leupers, Rainer; Takala, Jarmo

    2010-01-01

    The Handbook is organized in four parts. The first part motivates representative applications that drive and apply state-of-the art methods for design and implementation of signal processing systems; the second part discusses architectures for implementing these applications; the third part focuses on compilers and simulation tools; and the fourth part describes models of computation and their associated design tools and methodologies.

  6. Velocimetry signal synthesis with fringen.

    Energy Technology Data Exchange (ETDEWEB)

    Dolan, Daniel H., III

    2011-02-01

    An important part of velocimetry analysis is the recovery of a known velocity history from simulated data signals. The fringen program synthesizes VISAR and PDV signals, given a specified velocity history, using exact formulations for the optical signal. Time-dependent light conditions, non-ideal measurement conditions, and various diagnostic limitations (noise, etc.) may be incorporated into the simulated signals. This report describes the fringen program, which performs forward VISAR (Velocity Interferometer System for Any Reflector) and PDV (Photonic Doppler Velocimetry, also known as heterodyne velocimetry) analysis. Nearly all effects that might occur in VISAR/PDV measurement of a single velocity can be modeled by fringen. The program operates in MATLAB, either within a graphical interface or as a user-callable function. The current stable version of fringen is 0.3, which was released in October 2010. The following sections describe the operation and use of fringen. Section 2 gives a brief overview of VISAR and PDV synthesis. Section 3 illustrates the graphical and console interface of fringen. Section 4 presents several example uses of the program. Section 5 summarizes program capabilities and discusses potential future work.

  7. Meeting Report: Teaching Signal Transduction

    Science.gov (United States)

    Kramer, IJsbrand; Thomas, Geraint

    2006-01-01

    In July, 2005, the European Institute of Chemistry and Biology at the campus of the University of Bordeaux, France, hosted a focused week of seminars, workshops, and discussions around the theme of "teaching signal transduction." The purpose of the summer school was to offer both junior and senior university instructors a chance to reflect on the…

  8. Small Signal Loudspeaker Impedance Emulator

    DEFF Research Database (Denmark)

    Iversen, Niels Elkjær; Knott, Arnold

    2014-01-01

    from driver to driver. Therefore, a loudspeaker emulator capable of adjusting its impedance to that of a given driver is desired for measurement purposes. This paper proposes a loudspeaker emulator circuit for small signals. Simulations and experimental results are compared and show that it is possible...

  9. Calcium signaling in neocortical development.

    Science.gov (United States)

    Uhlén, Per; Fritz, Nicolas; Smedler, Erik; Malmersjö, Seth; Kanatani, Shigeaki

    2015-04-01

    The calcium ion (Ca(2+) ) is an essential second messenger that plays a pivotal role in neurogenesis. In the ventricular zone (VZ) of the neocortex, neural stem cells linger to produce progenitor cells and subsequently neurons and glial cells, which together build up the entire adult brain. The radial glial cells, with their characteristic radial fibers that stretch from the inner ventricular wall to the outer cortex, are known to be the neural stem cells of the neocortex. Migrating neurons use these radial fibers to climb from the proliferative VZ in the inner part of the brain to the outer layers of the cortex, where differentiation processes continue. To establish the complex structures that constitute the adult cerebral cortex, proliferation, migration, and differentiation must be tightly controlled by various signaling events, including cytosolic Ca(2+) signaling. During development, cells regularly exhibit spontaneous Ca(2+) activity that stimulates downstream effectors, which can elicit these fundamental cell processes. Spontaneous Ca(2+) activity during early neocortical development depends heavily on gap junctions and voltage dependent Ca(2+) channels, whereas later in development neurotransmitters and synapses exert an influence. Here, we provide an overview of the literature on Ca(2+) signaling and its impact on cell proliferation, migration, and differentiation in the neocortex. We point out important historical studies and review recent progress in determining the role of Ca(2+) signaling in neocortical development.

  10. Actin cytoskeleton regulates Hippo signaling.

    Directory of Open Access Journals (Sweden)

    Pradeep Reddy

    Full Text Available Hippo pathway controls the organ size by modulating cell proliferation and apoptosis. However, the upstream regulation of hippo signaling by actin cytoskeleton is not clear. To elucidate the role of actin as an upstream regulator of Hippo signaling, the levels of F (filamentous-actin in cells were elevated using jasplakinolide, an actin-stabilizing drug. Induction of F-actin formation in HeLa cells resulted in decreased phosphorylation of YAP, a key effector molecule for Hippo signaling. The activated YAP is localized to the cell nucleus and YAP increase was associated with increased expression of downstream CCN growth factors CCN1/CYR61 and CCN2/CTGF. The effect of the actin-stabilizing drug was blocked when YAP levels were suppressed in YAP "knock-down" cells. In summary, using an actin-stabilizing drug we show that actin cytoskeleton is one of the upstream regulators of Hippo signaling capable of activating YAP and increasing its downstream CCN growth factors.

  11. The Place of Signal processing

    OpenAIRE

    Mirhadi Seyed Arabi; Ali Gouya; Hamid Mirzaei

    2016-01-01

    “The Place of Signal processing” 2012. In: Workshop at Conference on Biomedical Science, by Scientific Society of Medical Engineering of Islamic Azad university of Tabriz. Presenter: Dr.Mirhadi Seyed Arabi, Dr.Ali Gouya and Dr.Hamid Mirzaei, 2012.

  12. Mathematical Modelling Plant Signalling Networks

    KAUST Repository

    Muraro, D.

    2013-01-01

    During the last two decades, molecular genetic studies and the completion of the sequencing of the Arabidopsis thaliana genome have increased knowledge of hormonal regulation in plants. These signal transduction pathways act in concert through gene regulatory and signalling networks whose main components have begun to be elucidated. Our understanding of the resulting cellular processes is hindered by the complex, and sometimes counter-intuitive, dynamics of the networks, which may be interconnected through feedback controls and cross-regulation. Mathematical modelling provides a valuable tool to investigate such dynamics and to perform in silico experiments that may not be easily carried out in a laboratory. In this article, we firstly review general methods for modelling gene and signalling networks and their application in plants. We then describe specific models of hormonal perception and cross-talk in plants. This mathematical analysis of sub-cellular molecular mechanisms paves the way for more comprehensive modelling studies of hormonal transport and signalling in a multi-scale setting. © EDP Sciences, 2013.

  13. Neural synchronization via potassium signaling

    DEFF Research Database (Denmark)

    Postnov, Dmitry E; Ryazanova, Ludmila S; Mosekilde, Erik;

    2006-01-01

    Using a relatively simple model we examine how variations of the extracellular potassium concentration can give rise to synchronization of two nearby pacemaker cells. With the volume of the extracellular space and the rate of potassium diffusion as control parameters, the dual nature...... junctional coupling, potassium signaling gives rise to considerable changes of the cellular response to external stimuli....

  14. Biophysical Aspects of Transmembrane Signaling

    CERN Document Server

    Damjanovich, Sandor

    2005-01-01

    Transmembrane signaling is one of the most significant cell biological events in the life and death of cells in general and lymphocytes in particular. Until recently biochemists and biophysicists were not accustomed to thinking of these processes from the side of a high number of complex biochemical events and an equally high number of physical changes at molecular and cellular levels at the same time. Both types of researchers were convinced that their findings are the most decisive, having higher importance than the findings of the other scientist population. Both casts were wrong. Life, even at cellular level, has a number of interacting physical and biochemical mechanisms, which finally build up the creation of an "excited" cell that will respond to particular signals from the outer or inner world. This book handles both aspects of the signalling events, and in some cases tries to unify our concepts and help understand the signals that govern the life and death of our cells. Not only the understanding, bu...

  15. BPSK Demodulation Using Digital Signal Processing

    Science.gov (United States)

    Garcia, Thomas R.

    1996-01-01

    A digital communications signal is a sinusoidal waveform that is modified by a binary (digital) information signal. The sinusoidal waveform is called the carrier. The carrier may be modified in amplitude, frequency, phase, or a combination of these. In this project a binary phase shift keyed (BPSK) signal is the communication signal. In a BPSK signal the phase of the carrier is set to one of two states, 180 degrees apart, by a binary (i.e., 1 or 0) information signal. A digital signal is a sampled version of a "real world" time continuous signal. The digital signal is generated by sampling the continuous signal at discrete points in time. The rate at which the signal is sampled is called the sampling rate (f(s)). The device that performs this operation is called an analog-to-digital (A/D) converter or a digitizer. The digital signal is composed of the sequence of individual values of the sampled BPSK signal. Digital signal processing (DSP) is the modification of the digital signal by mathematical operations. A device that performs this processing is called a digital signal processor. After processing, the digital signal may then be converted back to an analog signal using a digital-to-analog (D/A) converter. The goal of this project is to develop a system that will recover the digital information from a BPSK signal using DSP techniques. The project is broken down into the following steps: (1) Development of the algorithms required to demodulate the BPSK signal; (2) Simulation of the system; and (3) Implementation a BPSK receiver using digital signal processing hardware.

  16. On the Spectrum of Periodic Signals

    Science.gov (United States)

    Al-Smadi, Adnan

    2004-01-01

    In theory, there are many methods for the representation of signals. In practice, however, Fourier analysis involving the resolution of signals into sinusoidal components is used widely. There are several methods for Fourier analysis available for representation of signals. If the signal is periodic, then the Fourier series is used to represent…

  17. Dynamic range control of audio signals by digital signal processing

    Science.gov (United States)

    Gilchrist, N. H. C.

    It is often necessary to reduce the dynamic range of musical programs, particularly those comprising orchestral and choral music, for them to be received satisfactorily by listeners to conventional FM and AM broadcasts. With the arrival of DAB (Digital Audio Broadcasting) a much wider dynamic range will become available for radio broadcasting, although some listeners may prefer to have a signal with a reduced dynamic range. This report describes a digital processor developed by the BBC to control the dynamic range of musical programs in a manner similar to that of a trained Studio Manager. It may be used prior to transmission in conventional broadcasting, replacing limiters or other compression equipment. In DAB, it offers the possibility of providing a dynamic range control signal to be sent to the receiver via an ancillary data channel, simultaneously with the uncompressed audio, giving the listener the option of the full dynamic range or a reduced dynamic range.

  18. Reconstruction of harmonic signals based on bispectrum

    Institute of Scientific and Technical Information of China (English)

    FAN Yangyu; SUN Jincai; LI Pingan; XU Jiadong; SHANG Jiuhao

    2000-01-01

    A method for accurate reconstruction of the harmonic signals from bispectrum is presented. Based on the analysis of the measured harmonic signal, a sinusoid signal with 0phase, 1-amplitude and half of the fundamental frequency combines with the measured signal to form a combined signal, and then the bispectrum analysis is carried out to reconstruct the phase and the amplitude of the measured signal accurately. Without the zero-phase assumption of the fundamental component, using the new method eliminates the phase shifting between the calculated Fourier phase and the true Fourier phase in the existing signal retrieval methods based on bispectrum. The simulation results show the effectiveness of the new method.

  19. Fast Digitizing and Digital Signal Processing of Detector Signals

    OpenAIRE

    Hannaske, Roland

    2010-01-01

    A fast-digitizer data acquisition system recently installed at the neutron time-of-flight experiment nELBE, which is located at the superconducting electron accelerator ELBE of Forschungszentrum Dresden-Rossendorf, is tested with two different detector types. Preamplifier signals from a high-purity germanium detector are digitized, stored and finally processed. For a precise determination of the energy of the detected radiation, the moving-window deconvolution algorithm is used to compensate ...

  20. Afferent signals regulating food intake.

    Science.gov (United States)

    Bray, G A

    2000-08-01

    Food intake is a regulated system. Afferent signals provide information to the central nervous system, which is the centre for the control of satiety or food seeking. Such signals can begin even before food is ingested through visual, auditory and olfactory stimuli. One of the recent interesting findings is the demonstration that there are selective fatty acid taste receptors on the tongue of rodents. The suppression of food intake by essential fatty acids infused into the stomach and the suppression of electrical signals in taste buds reflect activation of a K rectifier channel (K 1.5). In animals that become fat eating a high-fat diet the suppression of this current by linoleic acid is less than that in animals that are resistant to obesity induced by dietary fat. Inhibition of fatty acid oxidation with either mercaptoacetate (which blocks acetyl-CoA dehydrogenase) or methylpalmoxirate will increase food intake. When animals have a choice of food, mercaptoacetate stimulates the intake of protein and carbohydrate, but not fat. Afferent gut signals also signal satiety. The first of these gut signals to be identified was cholecystokinin (CCK). When CCK acts on CCK-A receptors in the gastrointestinal tract, food intake is suppressed. These signals are transmitted by the vagus nerve to the nucleus tractus solitarius and thence to higher centres including the lateral parabrachial nucleus, amygdala, and other sites. Rats that lack the CCK-A receptor become obese, but transgenic mice lacking CCK-A receptors do not become obese. CCK inhibits food intake in human subjects. Enterostatin, the pentapeptide produced when pancreatic colipase is cleaved in the gut, has been shown to reduce food intake. This peptide differs in its action from CCK by selectively reducing fat intake. Enterostatin reduces hunger ratings in human subjects. Bombesin and its human analogue, gastrin inhibitory peptide (also gastrin-insulin peptide), reduce food intake in obese and lean subjects. Animals

  1. Signal-to-Signal Ratio Independent Speaker Identification for Co-channel Speech Signals

    DEFF Research Database (Denmark)

    Saeidi, Rahim; Mowlaee, Pejman; Kinnunen, Tomi;

    2010-01-01

    In this paper, we consider speaker identification for the co-channel scenario in which speech mixture from speakers is recorded by one microphone only. The goal is to identify both of the speakers from their mixed signal. High recognition accuracies have already been reported when an accurately e...... target speakers enlisted as three and two most probable speakers, respectively....

  2. Consistent Iterative Hard Thresholding for Signal Declipping

    OpenAIRE

    Kitic, Srdjan; Jacques, Laurent; Madhu, Nilesh; Hopwood, Michael Peter; Spriet, Ann; De Vleeschouwer, Christophe; International Conference on Acoustics, Speech, and Signal Processing (ICASSP) - 2013

    2013-01-01

    Clipping or saturation in audio signals is a very common problem in signal processing, for which, in the severe case, there is still no satisfactory solution. In such case, there is a tremendous loss of information, and traditional methods fail to appropriately recover the signal. We propose a novel approach for this signal restoration problem based on the framework of Iterative Hard Thresholding. This approach, which enforces the consistency of the reconstructed signal with the clipped obser...

  3. Multimedia signal coding and transmission

    CERN Document Server

    Ohm, Jens-Rainer

    2015-01-01

    This textbook covers the theoretical background of one- and multidimensional signal processing, statistical analysis and modelling, coding and information theory with regard to the principles and design of image, video and audio compression systems. The theoretical concepts are augmented by practical examples of algorithms for multimedia signal coding technology, and related transmission aspects. On this basis, principles behind multimedia coding standards, including most recent developments like High Efficiency Video Coding, can be well understood. Furthermore, potential advances in future development are pointed out. Numerous figures and examples help to illustrate the concepts covered. The book was developed on the basis of a graduate-level university course, and most chapters are supplemented by exercises. The book is also a self-contained introduction both for researchers and developers of multimedia compression systems in industry.

  4. Calcium signaling in lacrimal glands.

    Science.gov (United States)

    Putney, James W; Bird, Gary S

    2014-06-01

    Lacrimal glands provide the important function of lubricating and protecting the ocular surface. Failure of proper lacrimal gland function results in a number of debilitating dry eye diseases. Lacrimal glands secrete lipids, mucins, proteins, salts and water and these secretions are at least partially regulated by neurotransmitter-mediated cell signaling. The predominant signaling mechanism for lacrimal secretion involves activation of phospholipase C, generation of the Ca(2+)-mobilizing messenger, IP3, and release of Ca(2+) stored in the endoplasmic reticulum. The loss of Ca(2+) from the endoplasmic reticulum then triggers a process known as store-operated Ca(2+) entry, involving a Ca(2+) sensor in the endoplasmic reticulum, STIM1, which activates plasma membrane store-operated channels comprised of Orai subunits. Recent studies with deletions of the channel subunit, Orai1, confirm the important role of SOCE in both fluid and protein secretion in lacrimal glands, both in vivo and in vitro.

  5. Acoustic vector sensor signal processing

    Institute of Scientific and Technical Information of China (English)

    SUN Guiqing; LI Qihu; ZHANG Bin

    2006-01-01

    Acoustic vector sensor simultaneously, colocately and directly measures orthogonal components of particle velocity as well as pressure at single point in acoustic field so that is possible to improve performance of traditional underwater acoustic measurement devices or detection systems and extends new ideas for solving practical underwater acoustic engineering problems. Although acoustic vector sensor history of appearing in underwater acoustic area is no long, but with huge and potential military demands, acoustic vector sensor has strong development trend in last decade, it is evolving into a one of important underwater acoustic technology. Under this background, we try to review recent progress in study on acoustic vector sensor signal processing, such as signal detection, DOA estimation, beamforming, and so on.

  6. Cellular semiotics and signal transduction

    DEFF Research Database (Denmark)

    Bruni, Luis Emilio

    2007-01-01

    to the processes of sign interpretation and transmission between organisms of the same or different species). In Biosemiotics it is customary to recognise the cell as the most elementary integration unit for semiosis. Therefore intra and intercellular communication constitute the departure point for the study......Semiosis, the processes of production, communication and interpretation of signs - coding and de-coding - takes place within and between organisms. The term "endosemiosis" refers to the processes of interpretation and sign transmission inside an organism (as opposed to "exosemiosis", which refers...... considering semiotic logic in order to construct our understanding of living phenomena. Given the central integrating role of signal transduction in physiological and ecological studies, this chapter outlines its semiotic implications. The multi-modality and modularity of signal molecules and relative...

  7. Acoustic Localization with Infrasonic Signals

    Science.gov (United States)

    Threatt, Arnesha; Elbing, Brian

    2015-11-01

    Numerous geophysical and anthropogenic events emit infrasonic frequencies (wind turbines and tornadoes. These sounds, which cannot be heard by the human ear, can be detected from large distances (in excess of 100 miles) due to low frequency acoustic signals having a very low decay rate in the atmosphere. Thus infrasound could be used for long-range, passive monitoring and detection of these events. An array of microphones separated by known distances can be used to locate a given source, which is known as acoustic localization. However, acoustic localization with infrasound is particularly challenging due to contamination from other signals, sensitivity to wind noise and producing a trusted source for system development. The objective of the current work is to create an infrasonic source using a propane torch wand or a subwoofer and locate the source using multiple infrasonic microphones. This presentation will present preliminary results from various microphone configurations used to locate the source.

  8. Nuclear sensor signal processing circuit

    Science.gov (United States)

    Kallenbach, Gene A.; Noda, Frank T.; Mitchell, Dean J.; Etzkin, Joshua L.

    2007-02-20

    An apparatus and method are disclosed for a compact and temperature-insensitive nuclear sensor that can be calibrated with a non-hazardous radioactive sample. The nuclear sensor includes a gamma ray sensor that generates tail pulses from radioactive samples. An analog conditioning circuit conditions the tail-pulse signals from the gamma ray sensor, and a tail-pulse simulator circuit generates a plurality of simulated tail-pulse signals. A computer system processes the tail pulses from the gamma ray sensor and the simulated tail pulses from the tail-pulse simulator circuit. The nuclear sensor is calibrated under the control of the computer. The offset is adjusted using the simulated tail pulses. Since the offset is set to zero or near zero, the sensor gain can be adjusted with a non-hazardous radioactive source such as, for example, naturally occurring radiation and potassium chloride.

  9. Ambient temperature signalling in plants.

    Science.gov (United States)

    Wigge, Philip A

    2013-10-01

    Plants are exposed to daily and seasonal fluctuations in temperature. Within the 'ambient' temperature range (about 12-27°C for Arabidopsis) temperature differences have large effects on plant growth and development, disease resistance pathways and the circadian clock without activating temperature stress pathways. It is this developmental sensing and response to non-stressful temperatures that will be covered in this review. Recent advances have revealed key players in mediating temperature signals. The bHLH transcription factor PHYTOCHROME INTERACTING FACTOR4 (PIF4) has been shown to be a hub for multiple responses to warmer temperature in Arabidopsis, including flowering and hypocotyl elongation. Changes in chromatin state are involved in transmitting temperature signals to the transcriptome. Determining the precise mechanisms of temperature perception represents an exciting goal for the field.

  10. Signal and image multiresolution analysis

    CERN Document Server

    Ouahabi, Abdelialil

    2012-01-01

    Multiresolution analysis using the wavelet transform has received considerable attention in recent years by researchers in various fields. It is a powerful tool for efficiently representing signals and images at multiple levels of detail with many inherent advantages, including compression, level-of-detail display, progressive transmission, level-of-detail editing, filtering, modeling, fractals and multifractals, etc.This book aims to provide a simple formalization and new clarity on multiresolution analysis, rendering accessible obscure techniques, and merging, unifying or completing

  11. Epigenetics and Nutritional Environmental Signals

    OpenAIRE

    Mazzio, Elizabeth A.; Soliman, Karam F. A.

    2014-01-01

    All terrestrial life is influenced by multi-directional flows of information about its environment, enabling malleable phenotypic change through signals, chemical processes, or various forms of energy that facilitate acclimatization. Billions of biological co-inhabitants of the earth, including all plants and animals, collectively make up a genetic/epigenetic ecosystem by which adaptation/survival (inputs and outputs) are highly interdependent on one another. As an ecosystem, the solar system...

  12. Pricing and Signaling with Frictions

    OpenAIRE

    Alain Delacroix; Shouyong Shi

    2007-01-01

    We study a large market with directed search and signaling. Each seller chooses an investment that determines the quality of the good which is the seller's private information. A seller also chooses the price of the good and the number of selling sites. After observing sellers' choices of prices and sites, but not quality, buyers choose which price to search. The sites posting the same price and the buyers searching for that price match with each other randomly. In this environment, a seller'...

  13. Detection of signals in noise

    CERN Document Server

    McDonough, Robert N

    1995-01-01

    The Second Edition is an updated revision to the authors highly successful and widely used introduction to the principles and application of the statistical theory of signal detection. This book emphasizes those theories that have been found to be particularly useful in practice including principles applied to detection problems encountered in digital communications, radar, and sonar.Detection processing based upon the fast Fourier transform

  14. Cell signalling and phospholipid metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Boss, W.F.

    1990-01-01

    These studies explored whether phosphoinositide (PI) has a role in plants analogous to its role in animal cells. Although no parallel activity of PI in signal transduction was found in plant cells, activity of inositol phospholipid kinase was found to be modulated by light and by cell wall degrading enzymes. These studies indicate a major role for inositol phospholipids in plant growth and development as membrane effectors but not as a source of second messengers.

  15. Estrogen Signaling and Cardiovascular Disease

    OpenAIRE

    Murphy, Elizabeth

    2011-01-01

    Estrogen has pleiotropic effects on the cardiovascular system. The mechanisms by which estrogen confers these pleiotropic effects on cardiovascular function is under active investigation. Until a decade ago, all estrogen signaling was thought to occur by estrogen binding to nuclear estrogen receptors (ERα and ERβ), which bind to DNA and function as ligand activated transcription factors. Estrogen binding to the receptor alters gene expression thereby altering cell function. In 2000 estrogen w...

  16. SnapShot: Interferon Signaling.

    Science.gov (United States)

    Chow, Kwan T; Gale, Michael

    2015-12-17

    Interferons (IFNs) are crucial cytokines of antimicrobial, antitumor, and immunomodulatory activity. The three types of IFN (I, II, and III) are classified by their receptor specificity and sequence homology. IFNs are produced and secreted by cells in response to specific stimuli. Here, we review the subsequent IFN signaling events occurring through unique receptors leading to regulation of gene expression for modulation of innate and adaptive immunity. To view this SnapShot, open or download the PDF.

  17. Leptin signaling and leptin resistance

    OpenAIRE

    Zhou, Yingjiang; Rui, Liangyou

    2013-01-01

    Leptin is secreted into the bloodstream by adipocytes and is required for the maintenance of energy homeostasis and body weight. Leptin deficiency or genetic defects in the components of the leptin signaling pathways causes obesity. Leptin controls energy balance and body weight primarily by targeting LEPRb-expressing neurons in the brain, particularly in the hypothalamus. These LEPRb-expressing neurons function as the first-order neurons that project to the second-order neurons located withi...

  18. Signal detection in high dimension

    OpenAIRE

    Hallin, Marc; Moreira, Marcelo J.; Onatski, Alexei

    2012-01-01

    This paper deals with the local asymptotic structure, in the sense of Le Cam’s asymptotic theory of statistical experiments, of the signal detection problem in high dimension. More precisely, we consider the problem of testing the null hypothesis of sphericity of a high-dimensional covariance matrix against an alternative of (unspecified) multiple symmetry-breaking directions (multispiked alternatives). Simple analytical expressions for the asymptotic power envelope and the ...

  19. Engineering Cell-Cell Signaling

    OpenAIRE

    Blagovic, Katarina; Gong, Emily S.; Milano, Daniel F.; Natividad, Robert J.; Asthagiri, Anand R

    2013-01-01

    Juxtacrine cell-cell signaling mediated by the direct interaction of adjoining mammalian cells is arguably the mode of cell communication that is most recalcitrant to engineering. Overcoming this challenge is crucial for progress in biomedical applications, such as tissue engineering, regenerative medicine, immune system engineering and therapeutic design. Here, we describe the significant advances that have been made in developing synthetic platforms (materials and devices) and synthetic cel...

  20. Electromagnetic signals from planetary collisions

    OpenAIRE

    Zhang, Bing; Sigurdsson, Steinn

    2003-01-01

    Planet-planet collisions are expected during the early stages of the formation of extra-solar planets, and are also possible in mature planetary systems through secular planet-planet perturbations. We investigate the electromagnetic signals accompanied with these planetary collisions and their event rate, and explore the possibility of directly detecting such events. A typical Earth-Jupiter collision would give rise to a prompt EUV-soft-X-ray flash lasting for hours and a bright IR afterglow ...

  1. Dynamics in atomic signaling games

    KAUST Repository

    Fox, Michael J.

    2015-04-08

    We study an atomic signaling game under stochastic evolutionary dynamics. There are a finite number of players who repeatedly update from a finite number of available languages/signaling strategies. Players imitate the most fit agents with high probability or mutate with low probability. We analyze the long-run distribution of states and show that, for sufficiently small mutation probability, its support is limited to efficient communication systems. We find that this behavior is insensitive to the particular choice of evolutionary dynamic, a property that is due to the game having a potential structure with a potential function corresponding to average fitness. Consequently, the model supports conclusions similar to those found in the literature on language competition. That is, we show that efficient languages eventually predominate the society while reproducing the empirical phenomenon of linguistic drift. The emergence of efficiency in the atomic case can be contrasted with results for non-atomic signaling games that establish the non-negligible possibility of convergence, under replicator dynamics, to states of unbounded efficiency loss.

  2. Calcium Signals from the Vacuole

    Directory of Open Access Journals (Sweden)

    Gerald Schönknecht

    2013-10-01

    Full Text Available The vacuole is by far the largest intracellular Ca2+ store in most plant cells. Here, the current knowledge about the molecular mechanisms of vacuolar Ca2+ release and Ca2+ uptake is summarized, and how different vacuolar Ca2+ channels and Ca2+ pumps may contribute to Ca2+ signaling in plant cells is discussed. To provide a phylogenetic perspective, the distribution of potential vacuolar Ca2+ transporters is compared for different clades of photosynthetic eukaryotes. There are several candidates for vacuolar Ca2+ channels that could elicit cytosolic [Ca2+] transients. Typical second messengers, such as InsP3 and cADPR, seem to trigger vacuolar Ca2+ release, but the molecular mechanism of this Ca2+ release still awaits elucidation. Some vacuolar Ca2+ channels have been identified on a molecular level, the voltage-dependent SV/TPC1 channel, and recently two cyclic-nucleotide-gated cation channels. However, their function in Ca2+ signaling still has to be demonstrated. Ca2+ pumps in addition to establishing long-term Ca2+ homeostasis can shape cytosolic [Ca2+] transients by limiting their amplitude and duration, and may thus affect Ca2+ signaling.

  3. Cell signaling underlying epileptic behavior

    Directory of Open Access Journals (Sweden)

    Yuri eBozzi

    2011-08-01

    Full Text Available Epilepsy is a complex disease, characterized by the repeated occurrence of bursts of electrical activity (seizures in specific brain areas. The behavioral outcome of seizure events strongly depends on the brain regions that are affected by overactivity. Here we review the intracellular signaling pathways involved in the generation of seizures in epileptogenic areas. Pathways activated by modulatory neurotransmitters (dopamine, norepinephrine and serotonin, involving the activation of extracellular-regulated kinases (ERKs and the induction of immediate early genes (IEGs will be first discussed in relation to the occurrence of acute seizure events. Activation of immediate early genes has been proposed to lead to long-term molecular and behavioral responses induced by acute seizures. We also review deleterious consequences of seizure activity, focusing on the contribution of apoptosis-associated signaling pathways to the progression of the disease. A deep understanding of signaling pathways involved in both acute and long-term responses to seizures continues to be crucial to unravel the origins of epileptic behaviors and ultimately identify novel therapeutic targets for the cure of epilepsy.

  4. Calcium Signalling and Liver Regeneration

    Directory of Open Access Journals (Sweden)

    Isabelle Garcin

    2012-01-01

    Full Text Available After partial hepatectomy (PH the initial mass of the organ is restored through a complex network of cellular interactions that orchestrate both proliferative and hepatoprotective signalling cascades. Among agonists involved in this network many of them drive Ca2+ movements. During liver regeneration in the rat, hepatocyte cytosolic Ca2+ signalling has been shown on the one hand to be deeply remodelled and on the other hand to enhance progression of hepatocytes through the cell cycle. Mechanisms through which cytosolic Ca2+ signals impact on hepatocyte cell cycle early after PH are not completely understood, but at least they include regulation of immediate early gene transcription and ERK and CREB phosphorylation. In addition to cytosolic Ca2+, there is also evidence that mitochondrial Ca2+ and also nuclear Ca2+ may be critical for the regulation of liver regeneration. Finally, Ca2+ movements in hepatocytes, and possibly in other liver cells, not only impact hepatocyte progression in the cell cycle but more generally may regulate cellular homeostasis after PH.

  5. Expected geoneutrino signal at JUNO

    CERN Document Server

    Strati, Virginia; Callegari, Ivan; Mantovani, Fabio; McDonough, William F; Ricci, Barbara; Xhixha, Gerti

    2014-01-01

    Constraints on the Earth's composition and on its radiogenic energy budget come from the detection of geoneutrinos. The KamLAND and Borexino experiments recently reported the geoneutrino flux, which reflects the amount and distribution of U and Th inside the Earth. The KamLAND and Borexino experiments recently reported the geoneutrino flux, which reflects the amount and distribution of U and Th inside the Earth. The JUNO neutrino experiment, designed as a 20 kton liquid scintillator detector, will be built in an underground laboratory in South China about 53 km from the Yangjiang and Taishan nuclear power plants. Given the large detector mass and the intense reactor antineutrino flux, JUNO aims to collect high statistics antineutrino signals from reactors but also to address the challenge of discriminating the geoneutrino signal from the reactor background.The predicted geoneutrino signal at JUNO is 39.7 $^{+6.5}_{-5.2}$ TNU, based on the existing reference Earth model, with the dominant source of uncertainty...

  6. 49 CFR 236.514 - Interconnection of cab signal system with roadway signal system.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Interconnection of cab signal system with roadway signal system. 236.514 Section 236.514 Transportation Other Regulations Relating to Transportation... Interconnection of cab signal system with roadway signal system. The automatic cab signal system shall...

  7. BLIND COMPUTATION OF A SIGNAL USING SDR

    Directory of Open Access Journals (Sweden)

    M.BHUVANESHWARAN

    2012-05-01

    Full Text Available The most challenging aspect in signal processing is its hardware design. Today we are using multiple signals and each of it is at different frequency. The signal processing unit is a block in which the signal is processed to extract the exact message in the signal and it is mainly used to analyze each and every componentsof a signal. The block which is capable of doing all these things costs much. Thus the design of hardware components necessary to analyze the signal seems to be more difficult hence it needs huge amount of investment. In order to reduce the amount of money invested in the hardware design here in this paper we are presenting a new approach in signal processing called as software defined radio. Here the GNU RADIO acts as a software defined radio software and by using it we had successfully predicted the power, frequency spectrumand its peak amplitude of a speech signal.

  8. Nanotubes for noisy signal processing

    Science.gov (United States)

    Lee, Ian Yenyin

    Nanotubes can process noisy signals. We present two central results in support of this general thesis and make an informed extrapolation that uses nanotubes to improve body armor. The first result is that noise can help nanotubes detect weak signals. The finding confirmed a stochastic-resonance theoretical prediction that noise can enhance detection at the nano-level. Laboratory experiments with nanotubes showed that three types of noise improved three measures of detection. Small amounts of Gaussian, uniform, and Cauchy additive white noise increased mutual-information, cross-correlation, and bit-error-rate measures before degrading them with further increases in noise. Nanotubes can apply this noise-enhancement and nanotube electrical and mechanical properties to improve signal processing. Similar noise enhancement may benefit a proposed nanotube-array cochlear-model spectral processing. The second result is that nanotube antennas can directly detect narrowband electromagnetic (EM) signals. The finding showed that nanotube and thin-wire dipoles are similar: They are resonant and narrowband and can implement linear-array designs if the EM waves in the nanotubes propagate at or near the free-space velocity of light. The nanotube-antenna prediction is based on a Fresnel-zone or near-zone analysis of antenna impedance using a quantum-conductor model. The analysis also predicts a failure to resonate if the nanotube EM-wave propagation is much slower than free-space light propagation. We extrapolate based on applied and theoretical analysis of body armor. Field experiments used a baseball comparison and statistical and other techniques to model body-armor bruising effects. A baseball comparison showed that a large caliber handgun bullet can hit an armored chest as hard as a fast baseball can hit a bare chest. Adaptive fuzzy systems learned to predict a bruise profile directly from the experimental data and also from statistical analysis of the data. Nanotube signal

  9. Blurring in bar code signals

    Science.gov (United States)

    Tang, Hong

    1997-10-01

    When a bar code symbol is passed over a scanner, it is struck across by a fast moving laser beam. The laser light is scattered by the bar code. The total scattered power is modulated by the reflectivity of the bars and spaces in the symbol. A fraction of the scattered light is collected and focused onto a photodetector that converts the light variation into an electronic signal. The electronic signal is then digitized for analysis by a computer. The scanning and detection process can be modeled by a convolution of the laser beam profile and the bar code reflectivity function. The switching between states in the digitized bar code signal, which represents transitions from a space to a bar or vice versa, is determined by a zero-crossing point in the second derivative of the analog signal. The laser profile acts like a smoothing function. It blurs the analog electronic signal. If the width of the laser profile is less than the minimum width of bars and spaces in the bar code reflectivity function, the transition point is not affected by the location of its neighboring edges. If the laser profile is wider than the minimum width in the bar code, the transition point can be shifted due to the locations of its neighboring edges. The behavior of the shift of transition is analyzed here for all cases in a UPC symbol. It is found that the amount of shift in the transition point is almost the same for several different cases within the depth of field of the scanner. The knowledge of the behavior of transition point shift can be used to accurately compensate printing errors in an over-printed bar code. The modulation transfer function (MTF) of bar code scanning is the Fourier transform of the marginal function of the scanning laser beam. The MTF through focus for a scanning system is presented. By using an aperture with central obscuration in the laser focusing system, the high frequency resolution of bar code scanning can be enhanced and the depth of field of the scanner can

  10. Advanced digital signal processing and noise reduction

    CERN Document Server

    Vaseghi, Saeed V

    2008-01-01

    Digital signal processing plays a central role in the development of modern communication and information processing systems. The theory and application of signal processing is concerned with the identification, modelling and utilisation of patterns and structures in a signal process. The observation signals are often distorted, incomplete and noisy and therefore noise reduction, the removal of channel distortion, and replacement of lost samples are important parts of a signal processing system. The fourth edition of Advanced Digital Signal Processing and Noise Reduction updates an

  11. A METHOD AND A DEVICE FOR DETECTION OF A FIRST SIGNAL SUPERIMPOSED ON A SECOND SIGNAL

    DEFF Research Database (Denmark)

    2008-01-01

    The invention relates to a method and a device for detecting at least one first input signal superimposed on at least one second signal, the method comprising the steps of providing said at least one first input signal superimposed on at least one second signal to at least one half-wave rectifier......; transforming, in said at least one half-wave rectifier, said at least one first input signal superimposed on at least one second signal into a half-wave rectified signal; providing said half-wave rectified signal to an envelope detector; and transforming, in said envelope detector, said half-wave rectified...... signal into an envelope signal and wherein the at least one half-wave rectifier comprises at least one optoelectronic device. In this way, a simpler and cheaper method and/or device are provided for e.g. detecting a transmitted information signal superimposed on a high frequency carrier signal....

  12. Relaxin Signaling in Uterine Fibroids

    OpenAIRE

    Li, Zhen; Burzawa, Jennifer K.; Troung, Anne; Feng, Shu; Agoulnik, Irina U; Tong, Xiaowen; Anderson, Matthew L; Kovanci, Ertug; Rajkovic, Aleksandar; Agoulnik, Alexander I.

    2009-01-01

    Uterine fibroid is the most common tumor of female reproductive organs. The role of relaxin signaling in leiomyoma development was analyzed. We used 23 matched pairs of leiomyoma and normal myometrium samples to compare the expression of relaxin family peptide receptors RXFP1, RXFP2, caveolin 1, desmin, steroid receptors and their co-factors NCOR1 and NCOR2. The expression of RXFP1 evaluated by quantitative RT-PCR was down-regulated in fibroid tissues. Relaxin or INSL3 treatment suppressed TG...

  13. Fixed-point signal processing

    CERN Document Server

    Padgett, Wayne T

    2009-01-01

    This book is intended to fill the gap between the ""ideal precision"" digital signal processing (DSP) that is widely taught, and the limited precision implementation skills that are commonly required in fixed-point processors and field programmable gate arrays (FPGAs). These skills are often neglected at the university level, particularly for undergraduates. We have attempted to create a resource both for a DSP elective course and for the practicing engineer with a need to understand fixed-point implementation. Although we assume a background in DSP, Chapter 2 contains a review of basic theory

  14. Biomedical signals, imaging, and informatics

    CERN Document Server

    Bronzino, Joseph D

    2014-01-01

    Known as the bible of biomedical engineering, The Biomedical Engineering Handbook, Fourth Edition, sets the standard against which all other references of this nature are measured. As such, it has served as a major resource for both skilled professionals and novices to biomedical engineering.Biomedical Signals, Imaging, and Informatics, the third volume of the handbook, presents material from respected scientists with diverse backgrounds in biosignal processing, medical imaging, infrared imaging, and medical informatics.More than three dozen specific topics are examined, including biomedical s

  15. Physical limits to biochemical signaling

    CERN Document Server

    Bialek, W

    2003-01-01

    Many crucial biological processes operate with surprisingly small numbers of molecules, and there is renewed interest in analyzing the impact of noise associated with these small numbers. Twenty--five years ago, Berg and Purcell showed that bacterial chemotaxis, where a single celled organism must respond to small changes in concentration of chemicals outside the cell, is limited directly by molecule counting noise, and that aspects of the bacteria's behavioral and computational strategies must be chosen to minimize the effects of this noise. Here we revisit and generalize their arguments to estimate the physical limits to signaling processes within the cell, and argue that recent experiments are consistent with performance approaching these limits.

  16. Auditing ghosts by prosperity signals

    OpenAIRE

    Gideon Yaniv

    2003-01-01

    Ghosts are economic agents who evade taxes by failing to file a return. Knowing nothing about them, the tax agency is unable to track them down through audit strategies which are based on reported income. The present paper develops a simple model of the audit decision for a ghost-busting tax agency which bases its audit strategy on signals of prosperous living, such as ownership of high-quality housing. Ghosts have a preference for high-quality housing, but may opt to own houses of a lower qu...

  17. Are aposematic signals honest? A review.

    Science.gov (United States)

    Summers, K; Speed, M P; Blount, J D; Stuckert, A M M

    2015-09-01

    We explore the relevance of honest signalling theory to the evolution of aposematism. We begin with a general consideration of models of signal stability, with a focus on the Zahavian costly signalling framework. Next, we review early models of signalling in the context of aposematism (some that are consistent and some inconsistent with costly honest signalling). We focus on controversies surrounding the idea that aposematic signals are handicaps in a Zahavian framework. Then, we discuss how the alignment of interests between signaller and predator influences the evolution of aposematism, highlight the distinction between qualitative and quantitative honesty and review theory and research relevant to these categories. We also review recent theoretical treatments of the evolution of aposematism that have focused on honest signalling as well as empirical research on a variety of organisms, including invertebrates and frogs. Finally, we discuss future directions for empirical and theoretical research in this area. PMID:26079980

  18. Digital Signal Processing Based Biotelemetry Receivers

    Science.gov (United States)

    Singh, Avtar; Hines, John; Somps, Chris

    1997-01-01

    This is an attempt to develop a biotelemetry receiver using digital signal processing technology and techniques. The receiver developed in this work is based on recovering signals that have been encoded using either Pulse Position Modulation (PPM) or Pulse Code Modulation (PCM) technique. A prototype has been developed using state-of-the-art digital signal processing technology. A Printed Circuit Board (PCB) is being developed based on the technique and technology described here. This board is intended to be used in the UCSF Fetal Monitoring system developed at NASA. The board is capable of handling a variety of PPM and PCM signals encoding signals such as ECG, temperature, and pressure. A signal processing program has also been developed to analyze the received ECG signal to determine heart rate. This system provides a base for using digital signal processing in biotelemetry receivers and other similar applications.

  19. Analysis of ECG Signaling Using Wavelet Transform

    Directory of Open Access Journals (Sweden)

    O. P. Singh

    2013-02-01

    Full Text Available Analysis and monitoring of ElectroCardioGram (ECG gives information about the activities of the heart. Phenomena such as ECG contraction movement of body, respiration, power line interference, high frequency interference generate noise in signaling, which restricts the extraction of information from generated signal. For de-noising of ECG, wavelet transform technique has been implemented. ECG signal sampled at 500 Hz is taken as an input signal which has to be de-noised using Discrete Wavelet Transform (DWT technique. In this paper, we have decomposed the ECG signal up to the level three and then threshold the signal. The ECG signals with noise and without noise have been plotted. The de-noised ECG signal give better clearity as compared to noisy one that would help the experts to diagnose the patient in better ways. The simulation of the results is done with the help of MATLAB.

  20. Bioinformatics analyses for signal transduction networks

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Research in signaling networks contributes to a deeper understanding of organism living activities. With the development of experimental methods in the signal transduction field, more and more mechanisms of signaling pathways have been discovered. This paper introduces such popular bioin-formatics analysis methods for signaling networks as the common mechanism of signaling pathways and database resource on the Internet, summerizes the methods of analyzing the structural properties of networks, including structural Motif finding and automated pathways generation, and discusses the modeling and simulation of signaling networks in detail, as well as the research situation and tendency in this area. Now the investigation of signal transduction is developing from small-scale experiments to large-scale network analysis, and dynamic simulation of networks is closer to the real system. With the investigation going deeper than ever, the bioinformatics analysis of signal transduction would have immense space for development and application.

  1. Detection of Transient Signals in Doppler Spectra

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Signal processing is used to detect transient signals in the presence of noise. Two embodiments are disclosed. In both embodiments, the time series from a remote...

  2. Passive Hindrances Suppression Using Complex Polyphase Signals

    OpenAIRE

    Sumyk, Markiyan; Yankevych, Roman

    2010-01-01

    Using complex signals we get possibility of indemnification of passive hindrances in the single-channel system of radio monitoring due to the use of correlation and spectral characteristics of certain class of complex signals.

  3. Singapore signalling: the 2012 hedgehog pathway cocktail

    OpenAIRE

    Briscoe, James; Rohatgi, Rajat

    2012-01-01

    The ‘Hedgehog Signalling in Development Evolution and Disease' conference took place in Singapore in March 2012. It brought leading researchers together to discuss the latest findings, and exchange ideas, on every aspect of Hedgehog signalling.

  4. Extracting periodic driving signal from chaotic noise

    Institute of Scientific and Technical Information of China (English)

    MU Jing; TAO Chao; DU Gonghuan

    2003-01-01

    After periodic signals pass through some nonlinear systems, they are usually transformed into noise-like and wide-band chaotic signals. The discrete spectrums of the original periodic signals are often covered by the chaotic spectrums. Recovering the periodic driving signals from the chaotic signals is important not only in theory but also in practical applications. Based on the modeling theory of nonlinear dynamic system, a "polynomial-simple harmonic drive" non-autonomous equation (P-S equation) to approximate the original system is proposed and the approximation error between P-S equation and the original system is obtained. By changing the drive frequency, we obtain the curve of the approximation error vs. drive frequency. Based on the relation between this curve and the spectrums of the original periodic signals, the spectrum of the original driving signal is extracted and the original signal is recovered.

  5. Consistent Iterative Hard Thresholding for signal declipping

    OpenAIRE

    Kitić, Srđan; Jacques, Laurent; Madhu, Nilesh; Hopwood, Michael Peter; Spriet, Ann; De Vleeschauwer, Christophe

    2013-01-01

    International audience Clipping or saturation in audio signals is a very common problem in signal processing, for which, in the severe case, there is still no satisfactory solution. In such case, there is a tremendous loss of information, and traditional methods fail to appropriately recover the signal. We propose a novel approach for this signal restoration problem based on the framework of Iterative Hard Thresholding. This approach, which enforces the consistency of the reconstructed sig...

  6. Retinoic acid signaling in mammalian eye development

    OpenAIRE

    CVEKL, ALES; Wang, Wei-Lin

    2009-01-01

    Retinoic acid (RA) is a biologically active metabolite of vitamin A (retinol) that serves as a signaling molecule during a number of developmental and physiological processes. RA signaling plays multiple roles during embryonic eye development. RA signaling is initially required for reciprocal interactions between the optic vesicle and invaginating lens placode. RA signaling promotes normal development of the ventral retina and optic nerve through its activities in the neural crest cell-derive...

  7. Signaling among relatives. III. Talk is cheap

    OpenAIRE

    Bergstrom, Carl T.; Lachmann, Michael

    1998-01-01

    The Sir Philip Sidney game has been used by numerous authors to show how signal cost can facilitate honest signaling among relatives. Here, we demonstrate that, in this game, honest cost-free signals are possible as well, under very general conditions. Moreover, these cost-free signals are better for all participants than the previously explored alternatives. Recent empirical evidence suggests that begging is energetically inexpensive for nestling birds; this finding led some researchers to q...

  8. Redox signaling in acute pancreatitis.

    Science.gov (United States)

    Pérez, Salvador; Pereda, Javier; Sabater, Luis; Sastre, Juan

    2015-08-01

    Acute pancreatitis is an inflammatory process of the pancreatic gland that eventually may lead to a severe systemic inflammatory response. A key event in pancreatic damage is the intracellular activation of NF-κB and zymogens, involving also calcium, cathepsins, pH disorders, autophagy, and cell death, particularly necrosis. This review focuses on the new role of redox signaling in acute pancreatitis. Oxidative stress and redox status are involved in the onset of acute pancreatitis and also in the development of the systemic inflammatory response, being glutathione depletion, xanthine oxidase activation, and thiol oxidation in proteins critical features of the disease in the pancreas. On the other hand, the release of extracellular hemoglobin into the circulation from the ascitic fluid in severe necrotizing pancreatitis enhances lipid peroxidation in plasma and the inflammatory infiltrate into the lung and up-regulates the HIF-VEGF pathway, contributing to the systemic inflammatory response. Therefore, redox signaling and oxidative stress contribute to the local and systemic inflammatory response during acute pancreatitis.

  9. Prostaglandin Receptor Signaling in Disease

    Directory of Open Access Journals (Sweden)

    Toshiyuki Matsuoka

    2007-01-01

    Full Text Available Prostanoids, consisting of the prostaglandins (PGs and the thromboxanes (TXs, are a group of lipid mediators formed in response to various stimuli. They include PGD2, PGE2, PGF2α, PGI2, and TXA2. They are released outside of the cells immediately after synthesis, and exert their actions by binding to a G-protein coupled rhodopsin-type receptor on the surface of target cells. There are eight types of the prostanoid receptors conserved in mammals from mouse to human. They are the PGD receptor (DP, four subtypes of the PGE receptor (EP1, EP2, EP3, and EP4, the PGF receptor (FP, PGI receptor (IP, and TXA receptor (TP. Recently, mice deficient in each of these prostanoid receptors were generated and subjected to various experimental models of disease. These studies have revealed the roles of PG receptor signaling in various pathological conditions, and suggest that selective manipulation of the prostanoid receptors may be beneficial in treatment of the pathological conditions. Here we review these recent findings of roles of prostanoid receptor signaling and their therapeutic implications.

  10. TOR Signaling and Nutrient Sensing.

    Science.gov (United States)

    Dobrenel, Thomas; Caldana, Camila; Hanson, Johannes; Robaglia, Christophe; Vincentz, Michel; Veit, Bruce; Meyer, Christian

    2016-04-29

    All living organisms rely on nutrients to sustain cell metabolism and energy production, which in turn need to be adjusted based on available resources. The evolutionarily conserved target of rapamycin (TOR) protein kinase is a central regulatory hub that connects environmental information about the quantity and quality of nutrients to developmental and metabolic processes in order to maintain cellular homeostasis. TOR is activated by both nitrogen and carbon metabolites and promotes energy-consuming processes such as cell division, mRNA translation, and anabolism in times of abundance while repressing nutrient remobilization through autophagy. In animals and yeasts, TOR acts antagonistically to the starvation-induced AMP-activated kinase (AMPK)/sucrose nonfermenting 1 (Snf1) kinase, called Snf1-related kinase 1 (SnRK1) in plants. This review summarizes the immense knowledge on the relationship between TOR signaling and nutrients in nonphotosynthetic organisms and presents recent findings in plants that illuminate the crucial role of this pathway in conveying nutrient-derived signals and regulating many aspects of metabolism and growth.

  11. Gravitational Effects on Signal Transduction

    Science.gov (United States)

    Sytkowski, Arthur J.

    1999-01-01

    An understanding of the mechanisms by which individual cells perceive gravity and how these cells transduce and respond to gravitational stimuli is critical for the development of long-term manned space flight experiments. We now propose to use a well-characterized model erythroid cell system and to investigate gravitational perturbations of its erythropoietin (Epo) signaling pathway and gene regulation. Cells will be grown at 1-G and in simulated microgravity in the NASA Rotating Wall Vessel bioreactor (RWV). Cell growth and differentiation, the Epo-receptor, the protein kinase C pathway to the c-myc gene, and the protein phosphatase pathway to the c-myb gene will be studied and evaluated as reporters of gravitational stimuli. The results of these experiments will have impact on the problems of 1) gravitational sensing by individual cells, and 2) the anemia of space flight. This ground-based study also will serve as a Space Station Development Study in gravitational effects on intracellular signal transduction.

  12. Extracellular nucleotide signaling in plants

    Energy Technology Data Exchange (ETDEWEB)

    Stacey, Gary [Univ. of Missouri, Columbia, MO (United States)

    2016-09-08

    Over the life of this funded project, our research group identified and characterized two key receptor proteins in plants; one mediating the innate immunity response to chitin and the other elucidating the key receptor for extracellular ATP. In the case of chitin recognition, we recently described the quaternary structure of this receptor, shedding light on how the receptor functions. Perhaps more importantly, we demonstrated that all plants have the ability to recognize both chitin oligomers and lipochitooligosacchardes, fundamentally changing how the community views the evolution of these systems and strategies that might be used, for example, to extend symbiotic nitrogen fixation to non-legumes. Our discovery of DORN1 opens a new chapter in plant physiology documenting conclusively that eATP is an important extracellular signal in plants, as it is in animals. At this point, we cannot predict just how far reaching this discovery may prove to be but we are convinced that eATP signaling is fundamental to plant growth and development and, hence, we believe that the future will be very exciting for the study of DORN1 and its overall function in plants.

  13. Signaling pathways in diabetic nephropathy.

    Science.gov (United States)

    Kawanami, Daiji; Matoba, Keiichiro; Utsunomiya, Kazunori

    2016-10-01

    Diabetic nephropathy (DN) is a major cause of end-stage renal disease (ESRD), however, specific treatment for DN has not yet been elucidated. Therefore, it is critically important to understand the molecular mechanism underlying DN to develop cause-related therapeutic strategy. To date, various factors such as hemodynamic changes and metabolic pathways have been shown to be involved in the pathogenesis of DN. Excessive glucose influx activates cellular signaling pathways, including the diacylglycerol (DAG)-protein kinase C (PKC) pathway, advanced glycation end-products (AGE), polyol pathway, hexosamine pathway and oxidative stress. These factors interact with one another, thereby facilitating inflammatory processes, leading to the development of glomerulosclerosis under diabetic conditions. In addition to metabolic pathways, Rho-kinase, an effector of small-GTPase binding protein Rho, has been implicated as an important factor in the pathogenesis of DN. A number of studies have demonstrated that Rho-kinase plays key roles in the development of DN by inducing endothelial dysfunction, mesangial excessive extracellular matrix (ECM) production, podocyte abnormality, and tubulointerstitial fibrosis. In this review article, we describe our current understanding of the signaling pathways in DN. PMID:27094540

  14. CCN3 and calcium signaling

    Directory of Open Access Journals (Sweden)

    Li Chang Long

    2003-08-01

    Full Text Available Abstract The CCN family of genes consists presently of six members in human (CCN1-6 also known as Cyr61 (Cystein rich 61, CTGF (Connective Tissue Growth Factor, NOV (Nephroblastoma Overexpressed gene, WISP-1, 2 and 3 (Wnt-1 Induced Secreted Proteins. Results obtained over the past decade have indicated that CCN proteins are matricellular proteins, which are involved in the regulation of various cellular functions, such as proliferation, differentiation, survival, adhesion and migration. The CCN proteins have recently emerged as regulatory factors involved in both internal and external cell signaling. CCN3 was reported to physically interact with fibulin-1C, integrins, Notch and S100A4. Considering that, the conformation and biological activity of these proteins are dependent upon calcium binding, we hypothesized that CCN3 might be involved in signaling pathways mediated by calcium ions. In this article, we review the data showing that CCN3 regulates the levels of intracellular calcium and discuss potential models that may account for the biological effects of CCN3.

  15. Signal Frequency Spectra with Audacity®

    Science.gov (United States)

    Gailey, Alycia

    2015-01-01

    The primary objective of the activity presented here is to allow students to explore the frequency components of various simple signals, with the ultimate goal of teaching them how to remove unwanted noise from a voice signal. Analysis of the frequency components of a signal allows students to design filters that remove unwanted components of a…

  16. SIMULATION STUDY ON AIRBORNE SAR ECHO SIGNAL

    Institute of Scientific and Technical Information of China (English)

    Bao Houbing; Liu Zhao

    2004-01-01

    Through analyzing the influence on echo signal by factors of kinematical parameters of airborne SAR platform and radar antenna direction, this letter, on the basis of classical SAR echo signal analogue algorithm, puts forward certain airborne SAR echo signal analogue algorithm of distance directional frequency domain pulse coherent accumulation, and goes through simulation. The simulation results have proved the effectiveness of this algorithm.

  17. Quantum Pattern Recognition of Classical Signal

    OpenAIRE

    Pang, Chao-Yang; Ding, Cong-Bao; Hu, Ben-Qiong

    2007-01-01

    It's the key research topic of signal processing that recognizing genuine targets real time from the disturbed signal which has giant amount of data. A quantum algorithm for pattern recognition of classical signal which has time complexity O(sqrt(N)) is presented in this paper. Key Words: Pattern recognition, Grover's algorithm, Rotation on subspace

  18. 40 CFR 156.64 - Signal word.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Signal word. 156.64 Section 156.64... REQUIREMENTS FOR PESTICIDES AND DEVICES Human Hazard and Precautionary Statements § 156.64 Signal word. (a... signal word, reflecting the highest Toxicity Category (Category I is the highest toxicity category)...

  19. 49 CFR 236.806 - Signal, home.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Signal, home. 236.806 Section 236.806 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Signal, home. A roadway signal at the entrance to a route or block to govern trains in entering and...

  20. On the Asymptotic Distribution of Signal Fraction

    CERN Document Server

    Volobouev, Igor

    2016-01-01

    Condition of the asymptotic normality of the signal fraction estimate by maximum likelihood is derived under the null hypothesis of no signal. Consequences of this condition for determination of signal significance taking in to account the look elsewhere effect are discussed.

  1. Radar signal analysis and processing using Matlab

    CERN Document Server

    Mahafza, Bassem R

    2008-01-01

    Offering radar-related software for the analysis and design of radar waveform and signal processing, this book provides comprehensive coverage of radar signals and signal processing techniques and algorithms. It contains numerous graphical plots, common radar-related functions, table format outputs, and end-of-chapter problems. The complete set of MATLAB[registered] functions and routines are available for download online.

  2. Nonlinear filtering in ECG Signal Enhancement

    Directory of Open Access Journals (Sweden)

    N. Siddiah

    2012-02-01

    Full Text Available High resolution ECG signals are needed in measuring cardiac abnormalities analysis. Generally baseline wander is one of the important artifact occurred in ECG signal extraction, this strongly affects the signal quality. In order to facilitate proper diagnosis these artifacts have to be removed. In this paper various non linear, non adaptive filtering techniques are presented for the removal of baseline wander removal from ECG signals. The performance characteristics of various filtering techniques are measured in terms of signal to noise ratio.

  3. Signal transduction mechanisms in plants: an overview

    Science.gov (United States)

    Clark, G. B.; Thompson, G. Jr; Roux, S. J.

    2001-01-01

    This article provides an overview on recent advances in some of the basic signalling mechanisms that participate in a wide variety of stimulus-response pathways. The mechanisms include calcium-based signalling, G-protein-mediated-signalling and signalling involving inositol phospholipids, with discussion on the role of protein kinases and phosphatases interspersed. As a further defining feature, the article highlights recent exciting findings on three extracellular components that have not been given coverage in previous reviews of signal transduction in plants, extracellular calmodulin, extracellular ATP, and integrin-like receptors, all of which affect plant growth and development.

  4. A signal theoretic introduction to random processes

    CERN Document Server

    Howard, Roy M

    2015-01-01

    A fresh introduction to random processes utilizing signal theory By incorporating a signal theory basis, A Signal Theoretic Introduction to Random Processes presents a unique introduction to random processes with an emphasis on the important random phenomena encountered in the electronic and communications engineering field. The strong mathematical and signal theory basis provides clarity and precision in the statement of results. The book also features:  A coherent account of the mathematical fundamentals and signal theory that underpin the presented material Unique, in-depth coverage of

  5. Natural ranges of supersymmetric signals

    CERN Document Server

    Giusti, Leonardo; Strumia, A

    1999-01-01

    The LEP2 experiments pose a serious naturalness problem for supersymmetric models. The problem is stronger in gauge mediation than in supergravity models. Particular scenarios, like electroweak baryogenesis or gauge mediation with light messengers, are strongly disfavoured. Searching a theoretical reason that naturally explains why supersymmetry has not been found poses strong requests on model building. If instead an unlikely (p\\approx 5%) numerical accident has hidden supersymmetry to LEP2, we compute the naturalness distribution of values of allowed sparticle masses and supersymmetric loop effects. We find that b to s gamma remains a very promising signal of minimal supersymmetry even if there is now a 20% (4%) probability that coloured particles are heavier than 1 TeV (3 TeV). We study how much other effects are expected to be detectable.

  6. Digital signal processing using MATLAB

    CERN Document Server

    Schilling, Robert L

    2016-01-01

    Focus on the development, implementation, and application of modern DSP techniques with DIGITAL SIGNAL PROCESSING USING MATLAB(R), 3E. Written in an engaging, informal style, this edition immediately captures your attention and encourages you to explore each critical topic. Every chapter starts with a motivational section that highlights practical examples and challenges that you can solve using techniques covered in the chapter. Each chapter concludes with a detailed case study example, a chapter summary with learning outcomes, and practical homework problems cross-referenced to specific chapter sections for your convenience. DSP Companion software accompanies each book to enable further investigation. The DSP Companion software operates with MATLAB(R) and provides intriguing demonstrations as well as interactive explorations of analysis and design concepts.

  7. Signals of Supersymmetric Dark Matter

    CERN Document Server

    Abbas, A

    2000-01-01

    The Lightest Supersymmetric Particle predicted in most of the supersymmetric scenarios is an ideal candidate for the dark matter of cosmology. Their detection is of extreme significance today. Recently there have been intriguing signals of a 59 Gev neutralino dark matter at DAMA in Gran Sasso. We look at other possible signatures of dark matter in astrophysical and geological frameworks. The passage of the earth through dense clumps of dark matter would produce large quantities of heat in the interior of this planet through the capture and subsequent annihilation of dark matter particles. This heat would lead to large-scale volcanism which could in turn have caused mass extinctions. The periodicity of such volcanic outbursts agrees with the frequency of palaeontological mass extinctions as well as the observed periodicity in the occurrence of the largest flood basalt provinces on the globe. Binary character of these extinctions is another unique aspect of this signature of dark matter. In addition dark matter...

  8. Interplanetary GPS using pulsar signals

    Science.gov (United States)

    Becker, W.; Bernhardt, M. G.; Jessner, A.

    2015-11-01

    An external reference system suitable for deep space navigation can be defined by fast spinning and strongly magnetized neutron stars, called pulsars. Their beamed periodic signals have timing stabilities comparable to atomic clocks and provide characteristic temporal signatures that can be used as natural navigation beacons, quite similar to the use of GPS satellites for navigation on Earth. By comparing pulse arrival times measured on-board a spacecraft with predicted pulse arrivals at a reference location, the spacecraft position can be determined autonomously and with high accuracy everywhere in the solar system and beyond. The unique properties of pulsars make clear already today that such a navigation system will have its application in future astronautics. In this paper we describe the basic principle of spacecraft navigation using pulsars and report on the current development status of this novel technology.

  9. Fundamentals of adaptive signal processing

    CERN Document Server

    Uncini, Aurelio

    2015-01-01

    This book is an accessible guide to adaptive signal processing methods that equips the reader with advanced theoretical and practical tools for the study and development of circuit structures and provides robust algorithms relevant to a wide variety of application scenarios. Examples include multimodal and multimedia communications, the biological and biomedical fields, economic models, environmental sciences, acoustics, telecommunications, remote sensing, monitoring, and, in general, the modeling and prediction of complex physical phenomena. The reader will learn not only how to design and implement the algorithms but also how to evaluate their performance for specific applications utilizing the tools provided. While using a simple mathematical language, the employed approach is very rigorous. The text will be of value both for research purposes and for courses of study.

  10. Engagement Assessment Using EEG Signals

    Science.gov (United States)

    Li, Feng; Li, Jiang; McKenzie, Frederic; Zhang, Guangfan; Wang, Wei; Pepe, Aaron; Xu, Roger; Schnell, Thomas; Anderson, Nick; Heitkamp, Dean

    2012-01-01

    In this paper, we present methods to analyze and improve an EEG-based engagement assessment approach, consisting of data preprocessing, feature extraction and engagement state classification. During data preprocessing, spikes, baseline drift and saturation caused by recording devices in EEG signals are identified and eliminated, and a wavelet based method is utilized to remove ocular and muscular artifacts in the EEG recordings. In feature extraction, power spectrum densities with 1 Hz bin are calculated as features, and these features are analyzed using the Fisher score and the one way ANOVA method. In the classification step, a committee classifier is trained based on the extracted features to assess engagement status. Finally, experiment results showed that there exist significant differences in the extracted features among different subjects, and we have implemented a feature normalization procedure to mitigate the differences and significantly improved the engagement assessment performance.

  11. Comprehensive signal validation for nuclear power plants

    International Nuclear Information System (INIS)

    Signal validation is the detection, isolation and characterization of faulty signals. A signal validation technique utilizing a process hypercube comparison (PHC) was originated during the research and other methods were extended. The hypercube is merely a multi-dimensional joint histogram of the process conditions. The hypercube is created off-line during a learning phase. In the event that a newly observed plant state does not match with those in the learned hypercube, the PHC algorithm performs signal validation by progressively hypothesizing that one or more signals is in error. This assumption is then either substantiated or denied. In the case where many signals are found to be in error, a conclusion that the process conditions are abnormal is reached. A comprehensive signal validation software system has been developed for application to nuclear power plants. This system combines some previously established fault detection methodologies as well as some newly developed ones. The techniques have been implemented in a modular architecture which allows the addition or removal of signal validation modules as deemed necessary. Intra-module confidence factors describing the validity of a given signal are derived using fuzzy membership functions. A final evaluation of signal status is made by the System Executive (SE) based on results from each signal validation module. In order to make reliable decisions in this parallel system a positive decision maker (PDM) was developed

  12. Analysis on statistic characteristics of magnetotelluric signal

    Institute of Scientific and Technical Information of China (English)

    王书明; 王家映

    2004-01-01

    @@ For magnetotelluric sounding (MT), many processing methods based on power spectrum have put forward lots of hypotheses, such as MT signals are Gaussian, linear and minimum-phase. If practical signals do not satisfy these requirements, the results will have a few problems as follows. Firstly, when signals are non-linear and non-Gaussian, the information of the earth contained in the MT signals cannot be sufficiently extracted; Secondly, when signals are non-Gaussian and non-minimum phase, the processed results cannot reflect the minimum phase characteristics of the signals. Hence, it is necessary for us to do further research on characteristics of MT signals (YAO, SUN, 1999; LI, CHENG, 2002; Nikias, Petropulu, 1993; ZHANG, 1996). Otherwise, we cannot judge the reliability of the processed results based on power spectrum.

  13. ECG Signal Denoising By Wavelet Transform Thresholding

    Directory of Open Access Journals (Sweden)

    Mikhled Alfaouri

    2008-01-01

    Full Text Available In recent years, ECG signal plays an important role in the primary diagnosis, prognosis and survival analysis of heart diseases. In this paper a new approach based on the threshold value of ECG signal determination is proposed using Wavelet Transform coefficients. Electrocardiography has had a profound influence on the practice of medicine. The electrocardiogram signal contains an important amount of information that can be exploited in different manners. The ECG signal allows for the analysis of anatomic and physiologic aspects of the whole cardiac muscle. Different ECG signals are used to verify the proposed method using MATLAB software. Method presented in this paper is compared with the Donoho's method for signal denoising meanwhile better results are obtained for ECG signals by the proposed algorithm.

  14. Subaperture clutter filter with CFAR signal detection

    Energy Technology Data Exchange (ETDEWEB)

    Ormesher, Richard C.; Naething, Richard M.

    2016-08-30

    The various technologies presented herein relate to the determination of whether a received signal comprising radar clutter further comprises a communication signal. The communication signal can comprise of a preamble, a data symbol, communication data, etc. A first portion of the radar clutter is analyzed to determine a radar signature of the first portion of the radar clutter. A second portion of the radar clutter can be extracted based on the radar signature of the first portion. Following extraction, any residual signal can be analyzed to retrieve preamble data, etc. The received signal can be based upon a linear frequency modulation (e.g., a chirp modulation) whereby the chirp frequency can be determined and the frequency of transmission of the communication signal can be based accordingly thereon. The duration and/or bandwidth of the communication signal can be a portion of the duration and/or the bandwidth of the radar clutter.

  15. Diversity of optical signal processing led by optical signal form conversion

    Energy Technology Data Exchange (ETDEWEB)

    Konishi, Tsuyoshi, E-mail: konishi@mls.eng.osaka-u.ac.j [Osaka University, 2-1 Yamadaoka, Suita Osaka 565-0871 (Japan)

    2010-02-01

    This paper reviews opportunities of optical signal form conversion as typified by time-space conversion in optical signal processing. Several examples of typical ultra-fast optical signal processing using optical signal form conversion are described and their applications are introduced in respect to photonic networks, ultra-fast measurement, and so on.

  16. Validation of signal impact assessment tool in order to explore pharmacovigilance signals' follow-up actions

    NARCIS (Netherlands)

    Rolfes, Leàn; Kolfschoten, Judith; Van Hunsel, Florence; Van Puijenbroek, Eugene; van Grootheest, Kees

    2014-01-01

    Background: To determine which actions are advisable for signals arising from a spontaneous reporting system, the Netherlands Pharmacovigilance Centre Lareb uses a Signal Impact Assessment Tool (SIAT). It categorizes signals into one of four categories: strong/moderate signal strength and similarly

  17. Prediction of signal peptides and signal anchors by a hidden Markovmodel

    DEFF Research Database (Denmark)

    Nielsen, Henrik; Krogh, Anders Stærmose

    1998-01-01

    A hidden Markov model of signal peptides has been developed. It contains submodels for the N-terminal part, the hydrophobic region and the region around the cleavage site. For known signal peptides, the model can be used to assign objective boundaries between these three regions. Applied to our d...... is the poor discrimination between signal peptides and uncleaved signal anchors, but this is substantially improved by the hidden Markov model when expanding it with a very simple signal anchor model....

  18. Signal Traits and Oxidative Stress: A Comparative Study Across Populations with Divergent Signals

    OpenAIRE

    Vitousek, Maren N.; Oldřich eTomášek; Tomas eAlbrecht; Matthew R. Wilkins; Safran, Rebecca J.

    2016-01-01

    Diverging populations often shift patterns of signal use – a process that can contribute to reproductive isolation and speciation. Yet it is not clear why most traits gain or lose signal value during divergence. One reason this could occur is because changes in the relationship between signals and relevant physiological parameters degrade the reliability of a signal, or even change its underlying information content. Here we test the hypothesis that the relationship between signal trait elabo...

  19. Parameter estimation of sinusoidal signals by using principle of signal matched-phase

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A method for estimating frequency, amplitude and phase of a sinusoidal signal is presented based on the principle of signal matched-phase. The formulae for estimating signal parameters are derived, and the algorithm of searching for signal parameters is also given in the case where the signal frequency is unknown. The algorithm is simple and time_saving. The simulation results show that this new method is valid.

  20. The Hedgehog signalling pathway in bone formation

    Institute of Scientific and Technical Information of China (English)

    Jing Yang; Philipp Andre; Ling Ye; Ying-Zi Yang

    2015-01-01

    The Hedgehog (Hh) signalling pathway plays many important roles in development, homeostasis and tumorigenesis. The critical function of Hh signalling in bone formation has been identified in the past two decades. Here, we review the evolutionarily conserved Hh signalling mechanisms with an emphasis on the functions of the Hh signalling pathway in bone development, homeostasis and diseases. In the early stages of embryonic limb development, Sonic Hedgehog (Shh) acts as a major morphogen in patterning the limb buds. Indian Hedgehog (Ihh) has an essential function in endochondral ossification and induces osteoblast differentiation in the perichondrium. Hh signalling is also involved intramembrane ossification. Interactions between Hh and Wnt signalling regulate cartilage development, endochondral bone formation and synovial joint formation. Hh also plays an important role in bone homeostasis, and reducing Hh signalling protects against age-related bone loss. Disruption of Hh signalling regulation leads to multiple bone diseases, such as progressive osseous heteroplasia. Therefore, understanding the signalling mechanisms and functions of Hh signalling in bone development, homeostasis and diseases will provide important insights into bone disease prevention, diagnoses and therapeutics.

  1. Proteomic Study of the Brassinosteroid Signalling Network

    Institute of Scientific and Technical Information of China (English)

    Zhiyong Wang

    2012-01-01

    Plant growth is controlled by multiple environmental signals and endogenous hormones.In particular,brassinosteroid (BR) regulates a wide range of developmental processes throughout the life cycle of plants.BR acts through a receptor kinase signalling pathway,and BR signalling crosstalk with many other signalling pathways including light and gibberellin pathways as well as other receptor kinase pathways.My lab uses a combination of genetic,proteomic,and genomic approaches to elucidate not only the BR signaling pathway but also the global organization of the signaling network.We have successfully used proteomics to identify new components of the BR signalling pathway and to elucidated the mechanisms of signal transduction from the BRI1 receptor kinase to the BZR1 transcription factor.We have further uncovered mechanisms of crosstalk between different receptor kinase pathways,and we are dissecting the molecular mechanisms underlying signalling crosstalk and specificity.Our recent proteomic analysis of BR-regulated nuclear proteins has identified a potential link for BR regulation of flowering through RNA splicing and epigenetic mechanisms.I will discuss strategies and potential pitfalls in using proteomics to study signal transduction in plants.

  2. Epigenetics and nutritional environmental signals.

    Science.gov (United States)

    Mazzio, Elizabeth A; Soliman, Karam F A

    2014-07-01

    All terrestrial life is influenced by multi-directional flows of information about its environment, enabling malleable phenotypic change through signals, chemical processes, or various forms of energy that facilitate acclimatization. Billions of biological co-inhabitants of the earth, including all plants and animals, collectively make up a genetic/epigenetic ecosystem by which adaptation/survival (inputs and outputs) are highly interdependent on one another. As an ecosystem, the solar system, rotation of the planets, changes in sunlight, and gravitational pull influence cyclic epigenetic transitions and chromatin remodeling that constitute biological circadian rhythms controlling senescence. In humans, adverse environmental conditions such as poverty, stress, alcohol, malnutrition, exposure to pollutants generated from industrialization, man-made chemicals, and use of synthetic drugs can lead to maladaptive epigenetic-related illnesses with disease-specific genes being atypically activated or silenced. Nutrition and dietary practices are one of the largest facets in epigenetic-related metabolism, where specific "epi-nutrients" can stabilize the genome, given established roles in DNA methylation, histone modification, and chromatin remodeling. Moreover, food-based "epi-bioactive" constituents may reverse maladaptive epigenetic patterns, not only prior to conception and during fetal/early postnatal development but also through adulthood. In summary, in contrast to a static genomic DNA structure, epigenetic changes are potentially reversible, raising the hope for therapeutic and/or dietary interventions that can reverse deleterious epigenetic programing as a means to prevent or treat major illnesses. PMID:24861811

  3. Huntington's Disease and Striatal Signaling

    Directory of Open Access Journals (Sweden)

    Emmanuel eRoze

    2011-08-01

    Full Text Available Huntington’s Disease (HD is the most frequent neurodegenerative disease caused by an expansion of polyglutamines (CAG. The main clinical manifestations of HD are chorea, cognitive impairment and psychiatric disorders. The transmission of HD is autosomal dominant with a complete penetrance. HD has a single genetic cause, a well-defined neuropathology, and informative pre-manifest genetic testing of the disease is available. Striatal atrophy begins as early as 15 years before disease onset and continues throughout the period of manifest illness. Therefore, patients could theoretically benefit from therapy at early stages of the disease. One important characteristic of HD is the striatal vulnerability to neurodegeneration, despite similar expression of the protein in other brain areas. Aggregation of the mutated Huntingtin (HTT, impaired axonal transport, excitotoxicity, transcriptional dysregulation as well as mitochondrial dysfunction and energy deficits, are all part of the cellular events that underlie neuronal dysfunction and striatal death. Among these non-exclusive mechanisms, an alteration of striatal signaling is thought to orchestrate the downstream events involved in the cascade of striatal dysfunction.

  4. Advances in thermographic signal reconstruction

    Science.gov (United States)

    Shepard, Steven M.; Frendberg Beemer, Maria

    2015-05-01

    Since its introduction in 2001, the Thermographic Signal Reconstruction (TSR) method has emerged as one of the most widely used methods for enhancement and analysis of thermographic sequences, with applications extending beyond industrial NDT into biomedical research, art restoration and botany. The basic TSR process, in which a noise reduced replica of each pixel time history is created, yields improvement over unprocessed image data that is sufficient for many applications. However, examination of the resulting logarithmic time derivatives of each TSR pixel replica provides significant insight into the physical mechanisms underlying the active thermography process. The deterministic and invariant properties of the derivatives have enabled the successful implementation of automated defect recognition and measurement systems. Unlike most approaches to analysis of thermography data, TSR does not depend on flawbackground contrast, so that it can also be applied to characterization and measurement of thermal properties of flaw-free samples. We present a summary of recent advances in TSR, a review of the underlying theory and examples of its implementation.

  5. Automatic modulation recognition of communication signals

    CERN Document Server

    Azzouz, Elsayed Elsayed

    1996-01-01

    Automatic modulation recognition is a rapidly evolving area of signal analysis. In recent years, interest from the academic and military research institutes has focused around the research and development of modulation recognition algorithms. Any communication intelligence (COMINT) system comprises three main blocks: receiver front-end, modulation recogniser and output stage. Considerable work has been done in the area of receiver front-ends. The work at the output stage is concerned with information extraction, recording and exploitation and begins with signal demodulation, that requires accurate knowledge about the signal modulation type. There are, however, two main reasons for knowing the current modulation type of a signal; to preserve the signal information content and to decide upon the suitable counter action, such as jamming. Automatic Modulation Recognition of Communications Signals describes in depth this modulation recognition process. Drawing on several years of research, the authors provide a cr...

  6. Signal and Image Processing with Sinlets

    CERN Document Server

    Davydov, Alexander Y

    2012-01-01

    This paper presents a new family of localized orthonormal bases - sinlets - which are well suited for both signal and image processing and analysis. One-dimensional sinlets are related to specific solutions of the time-dependent harmonic oscillator equation. By construction, each sinlet is differentiable infinitely many times and has a well-defined and smoothly-varied instantaneous frequency known in analytical form. For square-integrable transient signals with infinite support, one-dimensional sinlet basis provides an advantageous alternative to the Fourier transform by rendering accurate signal representation via a countable set of real-valued coefficients. The properties of sinlets make them suitable for analyzing many real-world signals whose frequency content changes with time including radar and sonar waveforms, music, speech, biological echolocation sounds, biomedical signals, seismic acoustic waves, and signals employed in wireless communication systems. One-dimensional sinlet bases can be used to con...

  7. Signal processing by the endosomal system.

    Science.gov (United States)

    Villaseñor, Roberto; Kalaidzidis, Yannis; Zerial, Marino

    2016-04-01

    Cells need to decode chemical or physical signals from their environment in order to make decisions on their fate. In the case of signalling receptors, ligand binding triggers a cascade of chemical reactions but also the internalization of the activated receptors in the endocytic pathway. Here, we highlight recent studies revealing a new role of the endosomal network in signal processing. The diversity of entry pathways and endosomal compartments is exploited to regulate the kinetics of receptor trafficking, and interactions with specific signalling adaptors and effectors. By governing the spatio-temporal distribution of signalling molecules, the endosomal system functions analogously to a digital-analogue computer that regulates the specificity and robustness of the signalling response.

  8. Selection-Mutation Dynamics of Signaling Games

    Directory of Open Access Journals (Sweden)

    Josef Hofbauer

    2015-01-01

    Full Text Available We study the structure of the rest points of signaling games and their dynamic behavior under selection-mutation dynamics by taking the case of three signals as our canonical example. Many rest points of the replicator dynamics of signaling games are not isolated and, therefore, not robust under perturbations. However, some of them attract open sets of initial conditions. We prove the existence of certain rest points of the selection-mutation dynamics close to Nash equilibria of the signaling game and show that all but the perturbed rest points close to strict Nash equilibria are dynamically unstable. This is an important result for the evolution of signaling behavior, since it shows that the second-order forces that are governed by mutation can increase the chances of successful signaling.

  9. Evolution of Cooperation Via Covert Signaling

    CERN Document Server

    Smaldino, Paul E; McElreath, Richard

    2015-01-01

    Human sociality depends upon the benefits of mutual aid and extensive communication. However mutual aid is made difficult by the problems of coordinating diverse norms and preferences, and communication is harried by substantial ambiguity in meaning. Here we demonstrate that these two facts can work together to allow cooperation to develop, by the strategic use of deliberately ambiguous signals, covert signaling. Covert signaling is the transmission of information that is accurately received by its intended audience but obscured when perceived by others. Such signals may allow coordination and enhanced cooperation while also avoiding the alienation or hostile reactions of individuals with different preferences. Although the empirical literature has identified potential mechanisms of covert signaling, such as encryption in humor, there is to date no formal theory of its dynamics. We introduce a novel mathematical model to assess the conditions under which a covert signaling strategy will be favored. We show th...

  10. Wnt signaling: the good and the bad

    Institute of Scientific and Technical Information of China (English)

    Xi Chen; Jun Yang; Paul M Evans; Chunming Liu

    2008-01-01

    Since the first Wnt gene was identified in 1982,the functions and mechanisms of Wnt signaling have been extensively studied.Wnt signaling is conserved from invertebrates to vertebrates and regulates early embryonic development as well as the homeostasis of adult tissues.In addition,both embryonic stem cells and adult stem cells are regulated by Wnt signaling.Deregulation of Wnt signaling is associated with many human diseases,particularly cancers.In this review,we will discuss in detail the functions of many components involved in the Wnt signal transduction pathway.Then,we will explore what is known about the role of Wnt signaling in stem cells and cancers.

  11. Seizure detection algorithms based on EMG signals

    DEFF Research Database (Denmark)

    Conradsen, Isa

    Background: the currently used non-invasive seizure detection methods are not reliable. Muscle fibers are directly connected to the nerves, whereby electric signals are generated during activity. Therefore, an alarm system on electromyography (EMG) signals is a theoretical possibility. Objective......: to show whether medical signal processing of EMG data is feasible for detection of epileptic seizures. Methods: EMG signals during generalised seizures were recorded from 3 patients (with 20 seizures in total). Two possible medical signal processing algorithms were tested. The first algorithm was based...... the frequency-based algorithm was efficient for detecting the seizures in the third patient. Conclusion: Our results suggest that EMG signals could be used to develop an automatic seizuredetection system. However, different patients might require different types of algorithms /approaches....

  12. Why we need ESS signalling theory.

    Science.gov (United States)

    Grafen, A; Johnstone, R A

    1993-05-29

    Evolutionarily stable strategy (ESS) models of biological signalling are important because the intimate coevolution of signalling and receiving strategies is complicated. Tentative results from a numerical study of error-prone signalling show the value of formal modelling. Error in perception can create discreteness in the distribution of signals produced, and so observed discreteness in nature may call for no more complicated explanation. Further developments in the theory of signalling may include a link with theories of aggression such as the sequential assessment game. The technical device of a 'scratch space' may allow a natural development of 'two-way' information games in which each contestant plays the roles of signaller and receiver simultaneously. This device may also incidentally derive mental states from purely strategic considerations. PMID:8101658

  13. Signal and image processing in medical applications

    CERN Document Server

    Kumar, Amit; Rahim, B Abdul; Kumar, D Sravan

    2016-01-01

    This book highlights recent findings on and analyses conducted on signals and images in the area of medicine. The experimental investigations involve a variety of signals and images and their methodologies range from very basic to sophisticated methods. The book explains how signal and image processing methods can be used to detect and forecast abnormalities in an easy-to-follow manner, offering a valuable resource for researchers, engineers, physicians and bioinformatics researchers alike.

  14. Interactive Teaching of Adaptive Signal Processing

    OpenAIRE

    Stewart, R W; Harteneck, M; WEISS S.

    2000-01-01

    Over the last 30 years adaptive digital signal processing has progressed from being a strictly graduate level advanced class in signal processing theory to a topic that is part of the core curriculum for many undergraduate signal processing classes. The key reason is the continued advance of communications technology, with its need for echo control and equalisation, and the widespread use of adaptive filters in audio, biomedical, and control applications. In this paper we will review the basi...

  15. Measuring Team Creativity Through Longitudinal Social Signals

    OpenAIRE

    Gloor, Peter A.; Almozlino, Adam; Inbar, Orr; Lo, Wei; Provost, Shannon

    2014-01-01

    Research into human dynamical systems has long sought to identify robust signals for human behavior. We have discovered a series of social network-based indicators that are reliable predictors of team creativity and collaborative innovation. We extract these signals from electronic records of interpersonal interactions, including e-mail, and face-to-face interaction measured via sociometric badges. The first of these signals is Rotating Leadership, measuring the degree to which, over time, ac...

  16. Sonic hedgehog signaling during nervous system development

    Institute of Scientific and Technical Information of China (English)

    Qin Yang; Peng Xie

    2008-01-01

    The Hedgehog signaling pathway plays a key role in embryonic development and organ formation.Sonic hedgehog signaling participates in nervous system development,regulates proliferation and differentiation of neural stem cells,controls growth and targeting of axons,and contributes to specialization of oligodendrocytes.For further studies of the Sonic hedgehog signaling pathway and for the development of new drugs in the treatment of nervous system diseases,it is beneficial to understand these mechanisms.

  17. Digital Signal Processor For GPS Receivers

    Science.gov (United States)

    Thomas, J. B.; Meehan, T. K.; Srinivasan, J. M.

    1989-01-01

    Three innovative components combined to produce all-digital signal processor with superior characteristics: outstanding accuracy, high-dynamics tracking, versatile integration times, lower loss-of-lock signal strengths, and infrequent cycle slips. Three components are digital chip advancer, digital carrier downconverter and code correlator, and digital tracking processor. All-digital signal processor intended for use in receivers of Global Positioning System (GPS) for geodesy, geodynamics, high-dynamics tracking, and ionospheric calibration.

  18. Audible pedestrian signals :a feasibility study

    OpenAIRE

    Oliver, Morris Bernard

    1989-01-01

    This report represents a concentrated effort that determines the feasibility of audible pedestrian signals. These signals are devices which give auditory cues to help the visually impaired cross safely at difficult intersections. Surveys were sent out to over 100 organizations, audible signal manufacturers, and cities who have knowledge of the devices, and responses were analyzed. The devices were found to be feasible but only at certain complex and confusing intersect...

  19. Xampling: Compressed Sensing of Analog Signals

    OpenAIRE

    Mishali, Moshe; Eldar, Yonina C.

    2011-01-01

    Xampling generalizes compressed sensing (CS) to reduced-rate sampling of analog signals. A unified framework is introduced for low rate sampling and processing of signals lying in a union of subspaces. Xampling consists of two main blocks: Analog compression that narrows down the input bandwidth prior to sampling with commercial devices followed by a nonlinear algorithm that detects the input subspace prior to conventional signal processing. A variety of analog CS applications are reviewed wi...

  20. Bayesian modeling and classification of neural signals

    OpenAIRE

    Lewicki, Michael S.

    1994-01-01

    Signal processing and classification algorithms often have limited applicability resulting from an inaccurate model of the signal's underlying structure. We present here an efficient, Bayesian algorithm for modeling a signal composed of the superposition of brief, Poisson-distributed functions. This methodology is applied to the specific problem of modeling and classifying extracellular neural waveforms which are composed of a superposition of an unknown number of action potentials CAPs). ...

  1. Protein evolution on a human signaling network

    OpenAIRE

    Purisima Enrico O; Cui Qinghua; Wang Edwin

    2009-01-01

    Abstract Background The architectural structure of cellular networks provides a framework for innovations as well as constraints for protein evolution. This issue has previously been studied extensively by analyzing protein interaction networks. However, it is unclear how signaling networks influence and constrain protein evolution and conversely, how protein evolution modifies and shapes the functional consequences of signaling networks. In this study, we constructed a human signaling networ...

  2. Pyrvinium attenuates Hedgehog signaling downstream of Smoothened

    OpenAIRE

    Li, Bin; Fei, Dennis Liang; Flaveny, Colin A.; Dahmane, Nadia; Baubet, Valérie; Wang, Zhiqiang; Bai, Feng; Pei, Xin-Hai; Rodriguez-Blanco, Jezabel; Hang, Brian; Orton, Darren; Han, Lu; Wang, Baolin; Capobianco, Anthony J.; Lee, Ethan

    2014-01-01

    The Hedgehog (HH) signaling pathway represents an important class of emerging developmental signaling pathways that play critical roles in the genesis of a large number of human cancers. The pharmaceutical industry is currently focused on developing small molecules targeting Smoothened (Smo), a key signaling effector of the HH pathway that regulates the levels and activity of the Gli family of transcription factors. Although one of these compounds vismodegib is now FDA-approved for advanced b...

  3. Can Collimated Extraterrestrial Signals be Intercepted?

    OpenAIRE

    Forgan, Duncan H.

    2014-01-01

    The Optical Search for Extraterrestrial Intelligence (OSETI) attempts to detect collimated, narrowband pulses of electromagnetic radiation. These pulses may either consist of signals intentionally directed at the Earth, or signals between two star systems with a vector that unintentionally intersects the Solar System, allowing Earth to intercept the communication. But should we expect to be able to intercept these unintentional signals? And what constraints can we place upon the frequency of ...

  4. Detecting the Nonlinearity of Fish Acoustic Signals

    Institute of Scientific and Technical Information of China (English)

    REN Xinmin; YIN Li

    2006-01-01

    This paper discusses the nonlinearity of fish acoustic signals by using the surrogate data method.We compare the difference of three test statistics - time-irreversibility Trey, correlation dimension D2 and auto mutual information function Ⅰbetween the original data and the surrogate data.We come to the conclusion that there exists nonlinearity in the fish acoustic signals and there exist deterministic nonlinear components; therefore nonlinear dynamic theory can be used to analyze fish acoustic signals.

  5. Intercepting Bacterial Indole Signaling with Flustramine Derivatives

    OpenAIRE

    Bunders, Cynthia A.; Minvielle, Marine J.; Worthington, Roberta J.; Ortiz, Minoshka; Cavanagh, John; Melander, Christian

    2011-01-01

    Indole signaling is one of the putative universal signaling networks in bacteria. We have investigated the use of desformylflustrabromine (dFBr) derivatives for the inhibition of biofilm formation through modulation of the indole-signaling network in E. coli and S. aureus. We have found dFBr derivatives that are 10-1000 times more active than indole itself, demonstrating that the flustramine family of indolic natural products represent a privileged scaffold for the design of molecules to cont...

  6. The Signalling Role of Promotion in Japan

    OpenAIRE

    Kazuaki Okamura

    2011-01-01

    Under asymmetric information conditions regarding worker productivity between current and prospective employers, a worker's promotion signals his/her productivity. In this Paper, we tested the signalling role of promotion, using Japanese micro-level data. We found that among lower-level positions, promotion seems to signal a worker's ability, and both the business cycle and foreign-capital ratio of his/her company significantly strengthen this effects. These results suggest that external labo...

  7. CLASSIFICATION OF MPSK SIGNALS USING CUMULANT INVARIANTS

    Institute of Scientific and Technical Information of China (English)

    Yang Shaoquan; Chen Weidong

    2002-01-01

    A new feature based on higher order statistics is proposed for classification of MPSKsignals, which is invariant with respect to translation (shift), scale and rotation transforms of MPSK signal constellations, and can suppress additive color or white Gaussian noise. Application of the new feature to classification of MPSK signals, at medium signal-to-noise ratio with specified sample size, results in high probability of correct identification. Finally, computer simulations and comparisons with existing algorithms are given.

  8. QRS Complex Detection in Multilead ECG Signals

    OpenAIRE

    Šlancar, M.

    2015-01-01

    Automated analysis of HRV requires reliable detection of QRS complexes. We propose a detection method based on different combinations of three orthogonal (pseudoorthogonal) leads of human ECG signals. ECG signals were filtered by standard pass-band filter, Teager-Kaiser energy operator (TKEO) was applied on signal as envelope for detection. The most effective combination for QRS detection was a spatial velocity with sensitivity exceeds 99.9 % and positive predictive value near to 99.5 %. Det...

  9. Signalling by the cleaner shrimp Periclimenes longicarpus

    OpenAIRE

    Chapuis L.; Bshary R.

    2010-01-01

    Signals increase the fitness of a sender by altering the behaviour of receivers. For cooperative interactions biological market theory proposes that signalling strength may be linked to supply and demand. In this context, a recent laboratory experiment demonstrated that cleaner shrimps may advertise their service to client reef fish and that the advertisement is linked to hunger levels. We investigated signalling by the cleaner shrimp Periclimenes longicarpus in the field to test more detaile...

  10. L1-norm minimization for quaternion signals

    CERN Document Server

    Wu, Jiasong; Wang, Xiaoqing; Senhadji, Lotfi; Shu, Huazhong

    2012-01-01

    The l1-norm minimization problem plays an important role in the compressed sensing (CS) theory. We present in this letter an algorithm for solving the problem of l1-norm minimization for quaternion signals by converting it to second-order cone programming. An application example of the proposed algorithm is also given for practical guidelines of perfect recovery of quaternion signals. The proposed algorithm may find its potential application when CS theory meets the quaternion signal processing.

  11. Pseudo random signal processing theory and application

    CERN Document Server

    Zepernick, Hans-Jurgen

    2013-01-01

    In recent years, pseudo random signal processing has proven to be a critical enabler of modern communication, information, security and measurement systems. The signal's pseudo random, noise-like properties make it vitally important as a tool for protecting against interference, alleviating multipath propagation and allowing the potential of sharing bandwidth with other users. Taking a practical approach to the topic, this text provides a comprehensive and systematic guide to understanding and using pseudo random signals. Covering theoretical principles, design methodologies and applications

  12. [Weak signal detection in every heart cycle].

    Science.gov (United States)

    Yuan, J; Xu, X; Gao, D; Shi, G

    2001-12-01

    In this article, a new approach is introduced to lowering the myo-electronic noise in weak ECG signals. We use artificial neural network to make the noise be white, and then we adopt an adaptive filter of which the reference signal is achieved by extracting from other ECG cycle. The outcome is the reduction of both white noise and non-white noise in ECG signal. Satisfactory results have been achieved by using this method in the experiment of late potential detection.

  13. EDA Signaling and Skin Appendage Development

    OpenAIRE

    Cui, Chang-Yi; Schlessinger, David

    2006-01-01

    The same morphogenetic signals are often involved in the development of different organs. For developing skin appendages, a model for tissue-specific regulation of signaling is provided by the EDA pathway, which accesses the otherwise ubiquitous NFκB transcription factors. EDA signaling is mediated by ectodysplasin, EDAR and EDARADD, which form a new TNF ligand-receptor-adaptor family that is restricted to skin appendages in vertebrates from fish to human. The critical function of the pathway...

  14. Ultrafast Nonlinear Signal Processing in Silicon Waveguides

    DEFF Research Database (Denmark)

    Oxenløwe, Leif Katsuo; Mulvad, Hans Christian Hansen; Hu, Hao;

    2012-01-01

    We describe recent demonstrations of exploiting highly nonlinear silicon waveguides for ultrafast optical signal processing. We describe wavelength conversion and serial-to-parallel conversion of 640 Gbit/s data signals and 1.28 Tbit/s demultiplexing and all-optical sampling.......We describe recent demonstrations of exploiting highly nonlinear silicon waveguides for ultrafast optical signal processing. We describe wavelength conversion and serial-to-parallel conversion of 640 Gbit/s data signals and 1.28 Tbit/s demultiplexing and all-optical sampling....

  15. Improvements on Signal Processing for HF Radar

    Institute of Scientific and Technical Information of China (English)

    LIU Yongtan; SHEN Yiying

    2001-01-01

    In this paper improvements on signalprocessing are achieved to enhance the performancesof H-F radar system, being unobtainable by the con-ventional signal processing. Using the improved sig-nal processing both high range resolution and longcoherent integration time may be obtained for goodbenefit to the target resolution and weak signal de-tection. Modification to the unmatched correspon-dence between range delay samples and range resolu-tion ceils saves an additional accumulation loss in therange processing. Finally, comparisons between theimproved and the conventional signal processing aregiven by numerical simulation.

  16. Multivariate Analysis for the Processing of Signals

    Directory of Open Access Journals (Sweden)

    Beattie J.R.

    2014-01-01

    Full Text Available Real-world experiments are becoming increasingly more complex, needing techniques capable of tracking this complexity. Signal based measurements are often used to capture this complexity, where a signal is a record of a sample’s response to a parameter (e.g. time, displacement, voltage, wavelength that is varied over a range of values. In signals the responses at each value of the varied parameter are related to each other, depending on the composition or state sample being measured. Since signals contain multiple information points, they have rich information content but are generally complex to comprehend. Multivariate Analysis (MA has profoundly transformed their analysis by allowing gross simplification of the tangled web of variation. In addition MA has also provided the advantage of being much more robust to the influence of noise than univariate methods of analysis. In recent years, there has been a growing awareness that the nature of the multivariate methods allows exploitation of its benefits for purposes other than data analysis, such as pre-processing of signals with the aim of eliminating irrelevant variations prior to analysis of the signal of interest. It has been shown that exploiting multivariate data reduction in an appropriate way can allow high fidelity denoising (removal of irreproducible non-signals, consistent and reproducible noise-insensitive correction of baseline distortions (removal of reproducible non-signals, accurate elimination of interfering signals (removal of reproducible but unwanted signals and the standardisation of signal amplitude fluctuations. At present, the field is relatively small but the possibilities for much wider application are considerable. Where signal properties are suitable for MA (such as the signal being stationary along the x-axis, these signal based corrections have the potential to be highly reproducible, and highly adaptable and are applicable in situations where the data is noisy or

  17. Study on fractal features of modulation signals

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Based on fractal theory, the note presents a novel method of modulation signals classification that adopts box dimension and information dimension extracted from received signals as features of classification. These features contain the characteristics of magnitude, frequency and phase of signals, and collect discriminatory information among various modulation modes. They are effective features in classification sense, and are insensitive to noises interfering. The theoretical analysis also proves the above conclusion. The classifier design is very simple based on such features. The simulation results show that the performances of signal classification are superior.

  18. Bistatic SAR: Signal Processing and Image Formation.

    Energy Technology Data Exchange (ETDEWEB)

    Wahl, Daniel E.; Yocky, David A.

    2014-10-01

    This report describes the significant processing steps that were used to take the raw recorded digitized signals from the bistatic synthetic aperture RADAR (SAR) hardware built for the NCNS Bistatic SAR project to a final bistatic SAR image. In general, the process steps herein are applicable to bistatic SAR signals that include the direct-path signal and the reflected signal. The steps include preprocessing steps, data extraction to for a phase history, and finally, image format. Various plots and values will be shown at most steps to illustrate the processing for a bistatic COSMO SkyMed collection gathered on June 10, 2013 on Kirtland Air Force Base, New Mexico.

  19. Radar signal processing and its applications

    CERN Document Server

    Hummel, Robert; Stoica, Petre; Zelnio, Edmund

    2003-01-01

    Radar Signal Processing and Its Applications brings together in one place important contributions and up-to-date research results in this fast-moving area. In twelve selected chapters, it describes the latest advances in architectures, design methods, and applications of radar signal processing. The contributors to this work were selected from the leading researchers and practitioners in the field. This work, originally published as Volume 14, Numbers 1-3 of the journal, Multidimensional Systems and Signal Processing, will be valuable to anyone working or researching in the field of radar signal processing. It serves as an excellent reference, providing insight into some of the most challenging issues being examined today.

  20. Signals and systems primer with Matlab

    CERN Document Server

    Poularikas, Alexander D

    2006-01-01

    Signals and Systems Primer with MATLAB® equally emphasizes the fundamentals of both analog and digital signals and systems. To ensure insight into the basic concepts and methods, the text presents a variety of examples that illustrate a wide range of applications, from microelectromechanical to worldwide communication systems. It also provides MATLAB functions and procedures for practice and verification of these concepts.Taking a pedagogical approach, the author builds a solid foundation in signal processing as well as analog and digital systems. The book first introduces orthogonal signals,

  1. Vital physical signals measurements using a webcam

    Science.gov (United States)

    Ouyang, Jianfei; Yan, Yonggang; Yao, Lifeng

    2013-10-01

    Non-contact and remote measurements of vital physical signals are important for reliable and comfortable physiological self-assessment. In this paper, we provide a new video-based methodology for remote and fast measurements of vital physical signals such as cardiac pulse and breathing rate. A webcam is used to track color video of a human face or wrist, and a Photoplethysmography (PPG) technique is applied to perform the measurements of the vital signals. A novel sequential blind signal extraction methodology is applied to the color video under normal lighting conditions, based on correlation analysis between the green trace and the source signals. The approach is successfully applied in the measurement of vital signals under the condition of different illuminating in which the target signal can also be found out accurately. To assess the advantages, the measuring time of a large number of cases is recorded correctly. The experimental results show that it only takes less than 30 seconds to measure the vital physical signals using presented technique. The study indicates the proposed approach is feasible for PPG technique, which provides a way to study the relationship of the signal for different ROI in future research.

  2. Research of laser echo signal simulator

    Science.gov (United States)

    Xu, Rui; Shi, Rui; Wang, Xin; Li, Zhou

    2015-11-01

    Laser echo signal simulator is one of the most significant components of hardware-in-the-loop (HWIL) simulation systems for LADAR. System model and time series model of laser echo signal simulator are established. Some influential factors which could induce fixed error and random error on the simulated return signals are analyzed, and then these system insertion errors are analyzed quantitatively. Using this theoretical model, the simulation system is investigated experimentally. The results corrected by subtracting fixed error indicate that the range error of the simulated laser return signal is less than 0.25m, and the distance range that the system can simulate is from 50m to 20km.

  3. ARQ scheme reinforced with past acknowledgement signals

    Science.gov (United States)

    Nakamura, Makoto; Takada, Yasushi

    An ARQ (automatic-repeat-request) scheme that can reduce the influence of backward channel errors for bidirectional data transmission systems is proposed. The main feature of the scheme is that both present and past acknowledgement signals are utilized to decide whether the data signals should be retransmitted or not. Throughput performance is analyzed in both go-back-N and selective-repeat ARQ. A small number of returned past acknowledgement signals are required to improve the throughput efficiency. For an ideal selective-repeat ARQ with an infinite buffer, increasing the number of returned past acknowledgement signals makes the throughput efficiency asymptotically close to the upper bound.

  4. Advanced Methods of Biomedical Signal Processing

    CERN Document Server

    Cerutti, Sergio

    2011-01-01

    This book grew out of the IEEE-EMBS Summer Schools on Biomedical Signal Processing, which have been held annually since 2002 to provide the participants state-of-the-art knowledge on emerging areas in biomedical engineering. Prominent experts in the areas of biomedical signal processing, biomedical data treatment, medicine, signal processing, system biology, and applied physiology introduce novel techniques and algorithms as well as their clinical or physiological applications. The book provides an overview of a compelling group of advanced biomedical signal processing techniques, such as mult

  5. A new paradox in superluminal signaling

    CERN Document Server

    Fayngold, Moses

    2015-01-01

    A new paradox in superluminal signaling is presented. In contrast with the Tolman paradox with tachyon exchange between two parties, the new paradox appears already in a one-way superluminal signaling, even without creating the time loop. This produces a universal ban on any kind of superluminal signals, which is stronger than the Tolman paradox. Even though relativity embraces superluminal motions as such, thus making the world symmetric with respect to the invariant speed, the ineptness of all such motions for superluminal signaling makes the symmetry incomplete.

  6. Recovering a Clipped Signal in Sparseland

    CERN Document Server

    Weinstein, Alejandro J

    2011-01-01

    In many data acquisition systems it is common to observe signals whose amplitudes have been clipped. We present two new algorithms for recovering a clipped signal by leveraging the model assumption that the underlying signal is sparse in the frequency domain. Both algorithms employ ideas commonly used in the field of Compressive Sensing; the first is a modified version of Reweighted $\\ell_1$ minimization, and the second is a modification of a simple greedy algorithm known as Trivial Pursuit. An empirical investigation shows that both approaches can recover signals with significant levels of clipping

  7. Signalling and obfuscation for congestion control

    Science.gov (United States)

    Mareček, Jakub; Shorten, Robert; Yu, Jia Yuan

    2015-10-01

    We aim to reduce the social cost of congestion in many smart city applications. In our model of congestion, agents interact over limited resources after receiving signals from a central agent that observes the state of congestion in real time. Under natural models of agent populations, we develop new signalling schemes and show that by introducing a non-trivial amount of uncertainty in the signals, we reduce the social cost of congestion, i.e., improve social welfare. The signalling schemes are efficient in terms of both communication and computation, and are consistent with past observations of the congestion. Moreover, the resulting population dynamics converge under reasonable assumptions.

  8. The genetic algorithm for a signal enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Karimova, L. [Laboratory of Computer Modelling, Institute of Mathematics, Pushkin Street 125, 480100 Almaty (Kazakhstan)]. E-mail: karimova@math.kz; Kuadykov, E. [Laboratory of Computer Modelling, Institute of Mathematics, Pushkin Street 125, 480100 Almaty (Kazakhstan); Makarenko, N. [Laboratory of Computer Modelling, Institute of Mathematics, Pushkin Street 125, 480100 Almaty (Kazakhstan)

    2004-11-21

    The paper is devoted to the problem of time series enhancement, which is based on the analysis of local regularity. The model construction using this analysis does not require any a priori assumption on the structure of the noise and the functional relationship between original signal and noise. The signal itself may be nowhere differentiable with rapidly varying local regularity, what is overcome with the help of the new technique of increasing the local Hoelder regularity of the signal under research. A new signal with prescribed regularity is constructed using the genetic algorithm. This approach is applied to enhancement of time series in the paleoclimatology, solar physics, dendrochronology, meteorology and hydrology.

  9. Send mixed signals : earn more, work less

    DEFF Research Database (Denmark)

    Miltersen, Peter Bro; Sheffet, Or

    2012-01-01

    Emek et al presented a model of probabilistic single-item second price auctions where an auctioneer who is informed about the type of an item for sale, broadcasts a signal about this type to uninformed bidders. They proved that finding the optimal (for the purpose of generating revenue) pure...... that a mixed signaling scheme can in some cases generate twice as much revenue as the best pure signaling scheme and we prove a generally applicable lower bound on the revenue generated by the best mixed signaling scheme....

  10. Signal Representation and Processing using Operator Groups

    OpenAIRE

    Nordberg, Klas

    1994-01-01

    This thesis presents a signal representation in terms of operators. The signal is assumed to be an element of a vector space and subject to transformations of operators. The operators form continuous groups, so-called Lie groups. The representation can be used for signals in general, in particular if spatial relations are undefinied and it does not require a basis of the signal space to be useful. Special attention is given to orthogonal operator groups which are generated by anti-Hermitian o...

  11. Endocannabinoid Signaling Regulates Sleep Stability.

    Directory of Open Access Journals (Sweden)

    Matthew J Pava

    Full Text Available The hypnogenic properties of cannabis have been recognized for centuries, but endogenous cannabinoid (endocannabinoid regulation of vigilance states is poorly characterized. We report findings from a series of experiments in mice measuring sleep with polysomnography after various systemic pharmacological manipulations of the endocannabinoid system. Rapid, unbiased scoring of vigilance states was achieved using an automated algorithm that we devised and validated. Increasing endocannabinoid tone with a selective inhibitor of monoacyglycerol lipase (JZL184 or fatty acid amide hydrolase (AM3506 produced a transient increase in non-rapid eye movement (NREM sleep due to an augmentation of the length of NREM bouts (NREM stability. Similarly, direct activation of type 1 cannabinoid (CB1 receptors with CP47,497 increased NREM stability, but both CP47,497 and JZL184 had a secondary effect that reduced NREM sleep time and stability. This secondary response to these drugs was similar to the early effect of CB1 blockade with the antagonist/inverse agonist AM281, which fragmented NREM sleep. The magnitude of the effects produced by JZL184 and AM281 were dependent on the time of day this drug was administered. While activation of CB1 resulted in only a slight reduction in gamma power, CB1 blockade had dramatic effects on broadband power in the EEG, particularly at low frequencies. However, CB1 blockade did not significantly reduce the rebound in NREM sleep following total sleep deprivation. These results support the hypothesis that endocannabinoid signaling through CB1 is necessary for NREM stability but it is not necessary for sleep homeostasis.

  12. Processing Motion Signals in Complex Environments

    Science.gov (United States)

    Verghese, Preeti

    2000-01-01

    Motion information is critical for human locomotion and scene segmentation. Currently we have excellent neurophysiological models that are able to predict human detection and discrimination of local signals. Local motion signals are insufficient by themselves to guide human locomotion and to provide information about depth, object boundaries and surface structure. My research is aimed at understanding the mechanisms underlying the combination of motion signals across space and time. A target moving on an extended trajectory amidst noise dots in Brownian motion is much more detectable than the sum of signals generated by independent motion energy units responding to the trajectory segments. This result suggests that facilitation occurs between motion units tuned to similar directions, lying along the trajectory path. We investigated whether the interaction between local motion units along the motion direction is mediated by contrast. One possibility is that contrast-driven signals from motion units early in the trajectory sequence are added to signals in subsequent units. If this were the case, then units later in the sequence would have a larger signal than those earlier in the sequence. To test this possibility, we compared contrast discrimination thresholds for the first and third patches of a triplet of sequentially presented Gabor patches, aligned along the motion direction. According to this simple additive model, contrast increment thresholds for the third patch should be higher than thresholds for the first patch.The lack of a measurable effect on contrast thresholds for these various manipulations suggests that the pooling of signals along a trajectory is not mediated by contrast-driven signals. Instead, these results are consistent with models that propose that the facilitation of trajectory signals is achieved by a second-level network that chooses the strongest local motion signals and combines them if they occur in a spatio-temporal sequence consistent

  13. Phase synchronization of instrumental music signals

    Science.gov (United States)

    Mukherjee, Sayan; Palit, Sanjay Kumar; Banerjee, Santo; Ariffin, M. R. K.; Bhattacharya, D. K.

    2014-06-01

    Signal analysis is one of the finest scientific techniques in communication theory. Some quantitative and qualitative measures describe the pattern of a music signal, vary from one to another. Same musical recital, when played by different instrumentalists, generates different types of music patterns. The reason behind various patterns is the psycho-acoustic measures - Dynamics, Timber, Tonality and Rhythm, varies in each time. However, the psycho-acoustic study of the music signals does not reveal any idea about the similarity between the signals. For such cases, study of synchronization of long-term nonlinear dynamics may provide effective results. In this context, phase synchronization (PS) is one of the measures to show synchronization between two non-identical signals. In fact, it is very critical to investigate any other kind of synchronization for experimental condition, because those are completely non identical signals. Also, there exists equivalence between the phases and the distances of the diagonal line in Recurrence plot (RP) of the signals, which is quantifiable by the recurrence quantification measure τ-recurrence rate. This paper considers two nonlinear music signals based on same raga played by two eminent sitar instrumentalists as two non-identical sources. The psycho-acoustic study shows how the Dynamics, Timber, Tonality and Rhythm vary for the two music signals. Then, long term analysis in the form of phase space reconstruction is performed, which reveals the chaotic phase spaces for both the signals. From the RP of both the phase spaces, τ-recurrence rate is calculated. Finally by the correlation of normalized tau-recurrence rate of their 3D phase spaces and the PS of the two music signals has been established. The numerical results well support the analysis.

  14. A comb filter based signal processing method to effectively reduce motion artifacts from photoplethysmographic signals.

    Science.gov (United States)

    Peng, Fulai; Liu, Hongyun; Wang, Weidong

    2015-10-01

    A photoplethysmographic (PPG) signal can provide very useful information about a subject's cardiovascular status. Motion artifacts (MAs), which usually deteriorate the waveform of a PPG signal, severely obstruct its applications in the clinical diagnosis and healthcare area. To reduce the MAs from a PPG signal, in the present study we present a comb filter based signal processing method. Firstly, wavelet de-noising was implemented to preliminarily suppress a part of the MAs. Then, the PPG signal in the time domain was transformed into the frequency domain by a fast Fourier transform (FFT). Thirdly, the PPG signal period was estimated from the frequency domain by tracking the fundamental frequency peak of the PPG signal. Lastly, the MAs were removed by the comb filter which was designed based on the obtained PPG signal period. Experiments with synthetic and real-world datasets were implemented to validate the performance of the method. Results show that the proposed method can effectively restore the PPG signals from the MA corrupted signals. Also, the accuracy of blood oxygen saturation (SpO2), calculated from red and infrared PPG signals, was significantly improved after the MA reduction by the proposed method. Our study demonstrates that the comb filter can effectively reduce the MAs from a PPG signal provided that the PPG signal period is obtained. PMID:26334000

  15. A comb filter based signal processing method to effectively reduce motion artifacts from photoplethysmographic signals.

    Science.gov (United States)

    Peng, Fulai; Liu, Hongyun; Wang, Weidong

    2015-10-01

    A photoplethysmographic (PPG) signal can provide very useful information about a subject's cardiovascular status. Motion artifacts (MAs), which usually deteriorate the waveform of a PPG signal, severely obstruct its applications in the clinical diagnosis and healthcare area. To reduce the MAs from a PPG signal, in the present study we present a comb filter based signal processing method. Firstly, wavelet de-noising was implemented to preliminarily suppress a part of the MAs. Then, the PPG signal in the time domain was transformed into the frequency domain by a fast Fourier transform (FFT). Thirdly, the PPG signal period was estimated from the frequency domain by tracking the fundamental frequency peak of the PPG signal. Lastly, the MAs were removed by the comb filter which was designed based on the obtained PPG signal period. Experiments with synthetic and real-world datasets were implemented to validate the performance of the method. Results show that the proposed method can effectively restore the PPG signals from the MA corrupted signals. Also, the accuracy of blood oxygen saturation (SpO2), calculated from red and infrared PPG signals, was significantly improved after the MA reduction by the proposed method. Our study demonstrates that the comb filter can effectively reduce the MAs from a PPG signal provided that the PPG signal period is obtained.

  16. Method and device for signal time of arrival determination

    OpenAIRE

    Bellusci, G.; Janssen, G.J.M.

    2010-01-01

    A method for determining a time-of-arrival of an input signal, includes receiving the input signal; generating a first time dependent signal with a first time dependence from the received 5 input signal; generating a second time dependent signal with a second time dependence from the received input signal, the first time dependence of the first time dependent signal being different from the second time dependence of the second time dependent signal; sampling at least once the first time depen...

  17. G-CSF Protects Human Brain Vascular Endothelial Cells Injury Induced by High Glucose, Free Fatty Acids and Hypoxia through MAPK and Akt Signaling

    Science.gov (United States)

    Tao, Yinghong; Guo, Jingchun; Guo, Zhuangli; Zhang, Shuo; Zhang, Yu; Huang, Yanyan; Tang, Yuping; Dong, Qiang; Hu, Renming

    2015-01-01

    Granulocyte-colony stimulating factor (G-CSF) has been shown to play a neuroprotective role in ischemic stroke by mobilizing bone marrow (BM)-derived endothelial progenitor cells (EPCs), promoting angiogenesis, and inhibiting apoptosis. Impairments in mobilization and function of the BM-derived EPCs have previously been reported in animal and human studies of diabetes where there is both reduction in the levels of the BM-derived EPCs and its ability to promote angiogenesis. This is hypothesized to account for the pathogenesis of diabetic vascular complications such as stroke. Here, we sought to investigate the effects of G-CSF on diabetes-associated cerebral vascular defect. We observed that pretreatment of the cultured human brain vascular endothelial cells (HBVECs) with G-CSF largely prevented cell death induced by the combination stimulus with high glucose, free fatty acids (FFA) and hypoxia by increasing cell viability, decreasing apoptosis and caspase-3 activity. Cell ultrastructure measured by transmission electron microscope (TEM) revealed that G-CSF treatment nicely reduced combination stimulus-induced cell apoptosis. The results from fluorescent probe Fluo-3/AM showed that G-CSF greatly suppressed the levels of intracellular calcium ions under combination stimulus. We also found that G-CSF enhanced the expression of cell cycle proteins such as human cell division cycle protein 14A (hCdc14A), cyclinB and cyclinE, inhibited p53 activity, and facilitated cell cycle progression following combination stimulus. In addition, activation of extracellular signal-regulated kinase1/2 (ERK1/2) and Akt, and deactivation of c-Jun N terminal kinase (JNK) and p38 were proved to be required for the pro-survival effects of G-CSF on HBVECs exposed to combination stimulus. Overall, G-CSF is capable of alleviating HBVECs injury triggered by the combination administration with high glucose, FFA and hypoxia involving the mitogen-activated protein kinases (MAPK) and Akt signaling

  18. Looking for the hub in Fe signaling

    OpenAIRE

    Meiser, Johannes; Bauer, Petra

    2012-01-01

    Recently we could demonstrate that FIT is post-translationally regulated in way of protein turnover and that such turnover can be counteracted by the signaling compound NO. Here we summarize findings about FIT regulation and point out which signals and post-translational modifications could act on FIT activity to regulate iron uptake from the soil.

  19. Neuronal 'On' and 'Off' signals control microglia

    NARCIS (Netherlands)

    Biber, Knut; Neumann, Harald; Inoue, Kazuhide; Boddeke, Hendrikus W. G. M.

    2007-01-01

    Recent findings indicate that neurons are not merely passive targets of microglia but rather control microglial activity. The variety of different signals that neurons use to control microglia can be divided into two categories: 'Off' signals constitutively keep microglia in their resting state and

  20. SnapShot: Retinoic Acid Signaling

    OpenAIRE

    Kumar, Sandeep; Duester, Gregg

    2011-01-01

    Retinoic acid (RA), a lipid soluble signaling molecule derived from vitamin A (retinol), regulates diverse biological processes, including cellular proliferation, differentiation, and apoptosis, throughout embryonic development. RA controls the expression of genes involved in patterning and morphogenesis during organogenesis. Disruptions in the regulation of RA signaling results in several developmental disorders, including limb and skeletal defects, abnormal patterning of the central nervous...

  1. An Implantable CMOS Amplifier for Nerve Signals

    DEFF Research Database (Denmark)

    Nielsen, Jannik Hammel; Lehmann, Torsten

    2003-01-01

    . A continuous-time current-steering offset-compensation technique is utilized in order to minimize the noise contribution and to minimize dynamic impact on the amplifier input nodes. The method for signal recovery from noisy nerve signals is presented. A prototype amplifier is realized in a standard digital 0...

  2. SPdb – a signal peptide database

    Directory of Open Access Journals (Sweden)

    Tan Tin

    2005-10-01

    Full Text Available Abstract Background The signal peptide plays an important role in protein targeting and protein translocation in both prokaryotic and eukaryotic cells. This transient, short peptide sequence functions like a postal address on an envelope by targeting proteins for secretion or for transfer to specific organelles for further processing. Understanding how signal peptides function is crucial in predicting where proteins are translocated. To support this understanding, we present SPdb signal peptide database http://proline.bic.nus.edu.sg/spdb, a repository of experimentally determined and computationally predicted signal peptides. Results SPdb integrates information from two sources (a Swiss-Prot protein sequence database which is now part of UniProt and (b EMBL nucleotide sequence database. The database update is semi-automated with human checking and verification of the data to ensure the correctness of the data stored. The latest release SPdb release 3.2 contains 18,146 entries of which 2,584 entries are experimentally verified signal sequences; the remaining 15,562 entries are either signal sequences that fail to meet our filtering criteria or entries that contain unverified signal sequences. Conclusion SPdb is a manually curated database constructed to support the understanding and analysis of signal peptides. SPdb tracks the major updates of the two underlying primary databases thereby ensuring that its information remains up-to-date.

  3. A High-performance Small Signal Amplifier

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    According to questions in the design of high quality small signal amplifier, this paper gave a new-type high performance small signal amplifier. The paper selected the operational amplifier of ICL Company and designed a new-type circuit with simple, low cost and excellent performance.

  4. Male Mating Signaling in Social Dilemma Games

    DEFF Research Database (Denmark)

    Jensen, Niels Holm

    2013-01-01

    According to sexual selection theory and costly signaling theory, men benefit from signaling costly mate qualities to attractive women. To date, several studies have investigated whether men use conspicuous altruism to attract women, but the findings are mixed. This study investigated whether men...

  5. Impact of filtration elements on bioelectrical signal

    Science.gov (United States)

    Grigoriev, M.; Babich, L.

    2016-04-01

    Filtering of the wanted signal from the noise caused by power lines, magnetic pickup, interference from body movement, etc. in the field of medical data processing is a weighty problem of cardiography. To date, different types of digital filters have been used to clear the signal from unnecessary frequency bands. This paper presents the results of the filter simulation in MATLAB package.

  6. Signaling for Help. PAM Repeater, No. 56.

    Science.gov (United States)

    Ensign, Arselia S., Ed.

    Signaling devices can help individuals with disabilities call for help, see and feel sound, and monitor what is happening in another room. This pamphlet describes signaling devices within the following categories: emergency, telephone, doorbell, smoke and fire, baby cry and room monitor, light and vibrating, security, wake-up, and child monitor…

  7. Distortion Of Pressure Signals In Pneumatic Tubes

    Science.gov (United States)

    Whitmore, Stephen A.; Gilyard, Glenn B.; Curry, Robert; Lindsey, William

    1993-01-01

    NASA technical memorandum describes experimental investigation of distorting effects of propagation of pressure signals along narrow pneumatic tubes from pressure-sensing orifices on surfaces of models or aircraft to pressure sensors distant from orifices. Pressure signals distorted principally by frictional damping along walls of tubes and by reflections at orifice and sensor ends.

  8. Evolutionary origin of rhizobium Nod factor signaling

    NARCIS (Netherlands)

    Streng, A.; Camp, Op den R.; Bisseling, T.; Geurts, R.

    2011-01-01

    For over two decades now, it is known that the nodule symbiosis between legume plants and nitrogen fixing rhizobium bacteria is set in motion by the bacterial signal molecule named nodulation (Nod) factor.1 Upon Nod factor perception a signaling cascade is activated that is also essential for endomy

  9. Sparse signals estimation for adaptive sampling

    Directory of Open Access Journals (Sweden)

    Andrey Ordin

    2014-08-01

    Full Text Available This paper presents an estimation procedure for sparse signals in adaptive setting. We show that when the pure signal is strong enough, the value of loss function is asymptotically the same as for an optimal estimator up to a constant multiplier.

  10. Wnt signaling in liver physiology and pathology

    Institute of Scientific and Technical Information of China (English)

    Satdarshan P. Singh Monga

    2009-01-01

    @@ 1 Wnt/β-catenin signaling This signaling pathway is known to play key roles during development and in maintaining homeostasis in many adult tissues. Its aberrant activation is associated with cancers in many tissues such as breast, colon, pancreas, skin and liver.

  11. Acoustic Signal Feature Extraction of Vehicle Targets

    Institute of Scientific and Technical Information of China (English)

    蓝金辉; 马宝华; 李科杰

    2002-01-01

    Acoustic signal feature extraction is an important part of target recognition. The mechanisms for producing acoustic signals and their propagation are analyzed to extract the features of the radiated noise from different targets. Analysis of the acoustic spectra of typical vehicle targets acquired outdoors shows that the vehicles can be classified based on the acoustic spectra and amplitudes.

  12. Intestinal Hedgehog signaling in tumors and inflammation

    NARCIS (Netherlands)

    N.V.J.A. Büller

    2015-01-01

    In this thesis we investigated the role of Hedgehog signaling in tumors and inflammation. By using an inducible Indian Hedgehog (Ihh) knockout mouse we show that Ihh signals via the mesenchyme to the proliferating cells in the crypt to attenuate proliferation. Despite its anti-proliferative role in

  13. Net analyte signal based statistical quality control

    NARCIS (Netherlands)

    Skibsted, E.T.S.; Boelens, H.F.M.; Westerhuis, J.A.; Smilde, A.K.; Broad, N.W.; Rees, D.R.; Witte, D.T.

    2005-01-01

    Net analyte signal statistical quality control (NAS-SQC) is a new methodology to perform multivariate product quality monitoring based on the net analyte signal approach. The main advantage of NAS-SQC is that the systematic variation in the product due to the analyte (or property) of interest is sep

  14. Net analyte signal calculation for multivariate calibration

    NARCIS (Netherlands)

    Ferre, J.; Faber, N.M.

    2003-01-01

    A unifying framework for calibration and prediction in multivariate calibration is shown based on the concept of the net analyte signal (NAS). From this perspective, the calibration step can be regarded as the calculation of a net sensitivity vector, whose length is the amount of net signal when the

  15. Laser heterodyne interferometric signal processing method based on rising edge locking with high frequency clock signal.

    Science.gov (United States)

    Zhang, Enzheng; Chen, Benyong; Yan, Liping; Yang, Tao; Hao, Qun; Dong, Wenjun; Li, Chaorong

    2013-02-25

    A novel phase measurement method composed of the rising-edge locked signal processing and the digital frequency mixing is proposed for laser heterodyne interferometer. The rising-edge locked signal processing, which employs a high frequency clock signal to lock the rising-edges of the reference and measurement signals, not only can improve the steepness of the rising-edge, but also can eliminate the error counting caused by multi-rising-edge phenomenon in fringe counting. The digital frequency mixing is realized by mixing the digital interference signal with a digital base signal that is different from conventional frequency mixing with analogue signals. These signal processing can improve the measurement accuracy and enhance anti-interference and measurement stability. The principle and implementation of the method are described in detail. An experimental setup was constructed and a series of experiments verified the feasibility of the method in large displacement measurement with high speed and nanometer resolution.

  16. Spectral Correlation of Multicarrier Modulated Signals and Its Application for Signal Detection

    Directory of Open Access Journals (Sweden)

    Zhang Haijian

    2010-01-01

    Full Text Available Spectral correlation theory for cyclostationary time-series signals has been studied for decades. Explicit formulas of spectral correlation function for various types of analog-modulated and digital-modulated signals are already derived. In this paper, we investigate and exploit the cyclostationarity characteristics for two kinds of multicarrier modulated (MCM signals: conventional OFDM and filter bank based multicarrier (FBMC signals. The spectral correlation characterization of MCM signal can be described by a special linear periodic time-variant (LPTV system. Using this LPTV description, we have derived the explicit theoretical formulas of nonconjugate and conjugate cyclic autocorrelation function (CAF and spectral correlation function (SCF for OFDM and FBMC signals. According to theoretical spectral analysis, Cyclostationary Signatures (CS are artificially embedded into MCM signal and a low-complexity signature detector is, therefore, presented for detecting MCM signal. Theoretical analysis and simulation results demonstrate the efficiency and robustness of this CS detector compared to traditionary energy detector.

  17. Dynamic signaling in the Hog1 MAPK pathway relies on high basal signal transduction.

    Science.gov (United States)

    Macia, Javier; Regot, Sergi; Peeters, Tom; Conde, Núria; Solé, Ricard; Posas, Francesc

    2009-01-01

    Appropriate regulation of the Hog1 mitogen-activated protein kinase (MAPK) pathway is essential for cells to survive osmotic stress. Here, we show that the two sensing mechanisms upstream of Hog1 display different signaling properties. The Sho1 branch is an inducible nonbasal system, whereas the Sln1 branch shows high basal signaling that is restricted by a MAPK-mediated feedback mechanism. A two-dimensional mathematical model of the Snl1 branch, including high basal signaling and a Hog1-regulated negative feedback, shows that a system with basal signaling exhibits higher efficiency, with faster response times and higher sensitivity to variations in external signals, than would systems without basal signaling. Analysis of two other yeast MAPK pathways, the Fus3 and Kss1 signaling pathways, indicates that high intrinsic basal signaling may be a general property of MAPK pathways allowing rapid and sensitive responses to environmental changes. PMID:19318625

  18. Centralspindlin in Rappaport's cleavage signaling.

    Science.gov (United States)

    Mishima, Masanori

    2016-05-01

    Cleavage furrow in animal cell cytokinesis is formed by cortical constriction driven by contraction of an actomyosin network activated by Rho GTPase. Although the role of the mitotic apparatus in furrow induction has been well established, there remain discussions about the detailed molecular mechanisms of the cleavage signaling. While experiments in large echinoderm embryos highlighted the role of astral microtubules, data in smaller cells indicate the role of central spindle. Centralspindlin is a constitutive heterotetramer of MKLP1 kinesin and the non-motor CYK4 subunit and plays crucial roles in formation of the central spindle and recruitment of the downstream cytokinesis factors including ECT2, the major activator of Rho during cytokinesis, to the site of division. Recent reports have revealed a role of this centralspindlin-ECT2 pathway in furrow induction both by the central spindle and by the astral microtubules. Here, a unified view of the stimulation of cortical contractility by this pathway is discussed. Cytokinesis, the division of the whole cytoplasm, is an essential process for cell proliferation and embryonic development. In animal cells, cytokinesis is executed using a contractile network of actin filaments driven by a myosin-II motor that constricts the cell cortex (cleavage furrow ingression) into a narrow channel between the two daughter cells, which is resolved by scission (abscission) [1-3]. The anaphase-specific organization of the mitotic apparatus (MA, spindle with chromosomes plus asters) positions the cleavage furrow and plays a major role in spatial coupling between mitosis and cytokinesis [4-6]. The nucleus and chromosomes are dispensable for furrow specification [7-10], although they contribute to persistent furrowing and robust completion in some cell types [11,12]. Likewise, centrosomes are not essential for cytokinesis, but they contribute to the general fidelity of cell division [10,13-15]. Here, classical models of cleavage furrow

  19. Group-normalized wavelet packet signal processing

    Science.gov (United States)

    Shi, Zhuoer; Bao, Zheng

    1997-04-01

    Since the traditional wavelet and wavelet packet coefficients do not exactly represent the strength of signal components at the very time(space)-frequency tilling, group- normalized wavelet packet transform (GNWPT), is presented for nonlinear signal filtering and extraction from the clutter or noise, together with the space(time)-frequency masking technique. The extended F-entropy improves the performance of GNWPT. For perception-based image, soft-logic masking is emphasized to remove the aliasing with edge preserved. Lawton's method for complex valued wavelets construction is extended to generate the complex valued compactly supported wavelet packets for radar signal extraction. This kind of wavelet packets are symmetry and unitary orthogonal. Well-defined wavelet packets are chosen by the analysis remarks on their time-frequency characteristics. For real valued signal processing, such as images and ECG signal, the compactly supported spline or bi- orthogonal wavelet packets are preferred for perfect de- noising and filtering qualities.

  20. Electronic devices for analog signal processing

    CERN Document Server

    Rybin, Yu K

    2012-01-01

    Electronic Devices for Analog Signal Processing is intended for engineers and post graduates and considers electronic devices applied to process analog signals in instrument making, automation, measurements, and other branches of technology. They perform various transformations of electrical signals: scaling, integration, logarithming, etc. The need in their deeper study is caused, on the one hand, by the extension of the forms of the input signal and increasing accuracy and performance of such devices, and on the other hand, new devices constantly emerge and are already widely used in practice, but no information about them are written in books on electronics. The basic approach of presenting the material in Electronic Devices for Analog Signal Processing can be formulated as follows: the study with help from self-education. While divided into seven chapters, each chapter contains theoretical material, examples of practical problems, questions and tests. The most difficult questions are marked by a diamon...

  1. Clinical implications of hedgehog signaling pathway inhibitors

    Institute of Scientific and Technical Information of China (English)

    Hailan Liu; Dongsheng Gu; Jingwu Xie

    2011-01-01

    Hedgehog was first described in Drosophila melanogaster by the Nobel laureates Eric Wieschaus and Christiane Nusslein-Volhard. The hedgehog (Hh) pathway is a major regulator of cell differentiation,proliferation, tissue polarity, stem cell maintenance, and carcinogenesis. The first link of Hh signaling to cancer was established through studies of a rare familial disease, Gorlin syndrome, in 1996. Follow-up studies revealed activation of this pathway in basal cell carcinoma, medulloblastoma and, leukemia as well as in gastrointestinal, lung, ovarian, breast, and prostate cancer. Targeted inhibition of Hh signaling is now believed to be effective in the treatment and prevention of human cancer. The discovery and synthesis of specific inhibitors for this pathway are even more exciting. In this review, we summarize major advances in the understanding of Hh signaling pathway activation in human cancer, mouse models for studying Hhmediated carcinogenesis, the roles of Hh signaling in tumor development and metastasis, antagonists for Hh signaling and their clinical implications.

  2. Data Transmission Signal Design and Analysis

    Science.gov (United States)

    Moore, J. D.

    1972-01-01

    The error performances of several digital signaling methods are determined as a function of a specified signal-to-noise ratio. Results are obtained for Gaussian noise and impulse noise. Performance of a receiver for differentially encoded biphase signaling is obtained by extending the results of differential phase shift keying. The analysis presented obtains a closed-form answer through the use of some simplifying assumptions. The results give an insight into the analysis problem, however, the actual error performance may show a degradation because of the assumptions made in the analysis. Bipolar signaling decision-threshold selection is investigated. The optimum threshold depends on the signal-to-noise ratio and requires the use of an adaptive receiver.

  3. Sentra, a database of signal transduction proteins.

    Energy Technology Data Exchange (ETDEWEB)

    Maltsev, N.; Marland, E.; Yu, G. X.; Bhatnagar, S.; Lusk, R.; Mathematics and Computer Science

    2002-01-01

    Sentra (http://www-wit.mcs.anl.gov/sentra) is a database of signal transduction proteins with the emphasis on microbial signal transduction. The database was updated to include classes of signal transduction systems modulated by either phosphorylation or methylation reactions such as PAS proteins and serine/threonine kinases, as well as the classical two-component histidine kinases and methyl-accepting chemotaxis proteins. Currently, Sentra contains signal transduction proteins from 43 completely sequenced prokaryotic genomes as well as sequences from SWISS-PROT and TrEMBL. Signal transduction proteins are annotated with information describing conserved domains, paralogous and orthologous sequences, and conserved chromosomal gene clusters. The newly developed user interface supports flexible search capabilities and extensive visualization of the data.

  4. SENTRA, a database of signal transduction proteins.

    Energy Technology Data Exchange (ETDEWEB)

    D' Souza, M.; Romine, M. F.; Maltsev, N.; Mathematics and Computer Science; PNNL

    2000-01-01

    SENTRA, available via URL http://wit.mcs.anl.gov/WIT2/Sentra/, is a database of proteins associated with microbial signal transduction. The database currently includes the classical two-component signal transduction pathway proteins and methyl-accepting chemotaxis proteins, but will be expanded to also include other classes of signal transduction systems that are modulated by phosphorylation or methylation reactions. Although the majority of database entries are from prokaryotic systems, eukaroytic proteins with bacterial-like signal transduction domains are also included. Currently SENTRA contains signal transduction proteins in 34 complete and almost completely sequenced prokaryotic genomes, as well as sequences from 243 organisms available in public databases (SWISS-PROT and EMBL). The analysis was carried out within the framework of the WIT2 system, which is designed and implemented to support genetic sequence analysis and comparative analysis of sequenced genomes.

  5. Altered calcium signaling in cancer cells.

    Science.gov (United States)

    Stewart, Teneale A; Yapa, Kunsala T D S; Monteith, Gregory R

    2015-10-01

    It is the nature of the calcium signal, as determined by the coordinated activity of a suite of calcium channels, pumps, exchangers and binding proteins that ultimately guides a cell's fate. Deregulation of the calcium signal is often deleterious and has been linked to each of the 'cancer hallmarks'. Despite this, we do not yet have a full understanding of the remodeling of the calcium signal associated with cancer. Such an understanding could aid in guiding the development of therapies specifically targeting altered calcium signaling in cancer cells during tumorigenic progression. Findings from some of the studies that have assessed the remodeling of the calcium signal associated with tumorigenesis and/or processes important in invasion and metastasis are presented in this review. The potential of new methodologies is also discussed. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers.

  6. Targeting Notch Signaling in Colorectal Cancer.

    Science.gov (United States)

    Suman, Suman; Das, Trinath P; Ankem, Murali K; Damodaran, Chendil

    2014-12-01

    The activation of Notch signaling is implicated in tumorigenesis in the colon due to the induction of pro-survival signaling in colonic epithelial cells. Chemoresistance is a major obstacle for treatment and for the complete eradication of colorectal cancer (CRC), hence, the inhibition of Notch is an attractive target for CRC and several groups are working to identify small molecules or monoclonal antibodies that inhibit Notch or its downstream events; however, toxicity profiles in normal cells and organs often impede the clinical translation of these molecules. Dietary agents have gained momentum for targeting several pro-survival signaling cascades, and recent studies demonstrated that agents that inhibit Notch signaling result in growth inhibition in preclinical models of CRC. In this review, we focus on the importance of Notch as a preventive and therapeutic target for colon cancer and on the effect of WA on this signaling pathway in the context of colon cancer. PMID:25395896

  7. Complexity of Receptor Tyrosine Kinase Signal Processing

    Science.gov (United States)

    Volinsky, Natalia; Kholodenko, Boris N.

    2013-01-01

    Our knowledge of molecular mechanisms of receptor tyrosine kinase (RTK) signaling advances with ever-increasing pace. Yet our understanding of how the spatiotemporal dynamics of RTK signaling control specific cellular outcomes has lagged behind. Systems-centered experimental and computational approaches can help reveal how overlapping networks of signal transducers downstream of RTKs orchestrate specific cell-fate decisions. We discuss how RTK network regulatory structures, which involve the immediate posttranslational and delayed transcriptional controls by multiple feed forward and feedback loops together with pathway cross talk, adapt cells to the combinatorial variety of external cues and conditions. This intricate network circuitry endows cells with emerging capabilities for RTK signal processing and decoding. We illustrate how mathematical modeling facilitates our understanding of RTK network behaviors by unraveling specific systems properties, including bistability, oscillations, excitable responses, and generation of intricate landscapes of signaling activities. PMID:23906711

  8. Surface Electromyography Signal Processing and Classification Techniques

    Directory of Open Access Journals (Sweden)

    Tae G. Chang

    2013-09-01

    Full Text Available Electromyography (EMG signals are becoming increasingly important in many applications, including clinical/biomedical, prosthesis or rehabilitation devices, human machine interactions, and more. However, noisy EMG signals are the major hurdles to be overcome in order to achieve improved performance in the above applications. Detection, processing and classification analysis in electromyography (EMG is very desirable because it allows a more standardized and precise evaluation of the neurophysiological, rehabitational and assistive technological findings. This paper reviews two prominent areas; first: the pre-processing method for eliminating possible artifacts via appropriate preparation at the time of recording EMG signals, and second: a brief explanation of the different methods for processing and classifying EMG signals. This study then compares the numerous methods of analyzing EMG signals, in terms of their performance. The crux of this paper is to review the most recent developments and research studies related to the issues mentioned above.

  9. Surface Electromyography Signal Processing and Classification Techniques

    Science.gov (United States)

    Chowdhury, Rubana H.; Reaz, Mamun B. I.; Ali, Mohd Alauddin Bin Mohd; Bakar, Ashrif A. A.; Chellappan, Kalaivani; Chang, Tae. G.

    2013-01-01

    Electromyography (EMG) signals are becoming increasingly important in many applications, including clinical/biomedical, prosthesis or rehabilitation devices, human machine interactions, and more. However, noisy EMG signals are the major hurdles to be overcome in order to achieve improved performance in the above applications. Detection, processing and classification analysis in electromyography (EMG) is very desirable because it allows a more standardized and precise evaluation of the neurophysiological, rehabitational and assistive technological findings. This paper reviews two prominent areas; first: the pre-processing method for eliminating possible artifacts via appropriate preparation at the time of recording EMG signals, and second: a brief explanation of the different methods for processing and classifying EMG signals. This study then compares the numerous methods of analyzing EMG signals, in terms of their performance. The crux of this paper is to review the most recent developments and research studies related to the issues mentioned above. PMID:24048337

  10. Signal Classification for Acoustic Neutrino Detection

    CERN Document Server

    Neff, M; Enzenhöfer, A; Graf, K; Hößl, J; Katz, U; Lahmann, R; Richardt, C

    2011-01-01

    This article focuses on signal classification for deep-sea acoustic neutrino detection. In the deep sea, the background of transient signals is very diverse. Approaches like matched filtering are not sufficient to distinguish between neutrino-like signals and other transient signals with similar signature, which are forming the acoustic background for neutrino detection in the deep-sea environment. A classification system based on machine learning algorithms is analysed with the goal to find a robust and effective way to perform this task. For a well-trained model, a testing error on the level of one percent is achieved for strong classifiers like Random Forest and Boosting Trees using the extracted features of the signal as input and utilising dense clusters of sensors instead of single sensors.

  11. Handbook of Signal Processing in Acoustics

    CERN Document Server

    Havelock, David; Vorländer, Michael

    2009-01-01

    The Handbook of Signal Processing in Acoustics presents signal processing as it is practiced in the field of acoustics. The Handbook is organized by areas of acoustics, with recognized leaders coordinating the self-contained chapters of each section. It brings together a wide range of perspectives from over 100 authors to reveal the interdisciplinary nature of signal processing in acoustics. Success in acoustic applications often requires juggling both the acoustic and the signal processing parameters of the problem. This handbook brings the key issues from both into perspective and is complementary to other reference material on the two subjects. It is a unique resource for experts and practitioners alike to find new ideas and techniques within the diversity of signal processing in acoustics.

  12. Hedgehog Signaling in Pancreatic Fibrosis and Cancer.

    Science.gov (United States)

    Bai, Yongyu; Bai, Yongheng; Dong, Jiaojiao; Li, Qiang; Jin, Yuepeng; Chen, Bicheng; Zhou, Mengtao

    2016-03-01

    The hedgehog signaling pathway was first discovered in the 1980s. It is a stem cell-related pathway that plays a crucial role in embryonic development, tissue regeneration, and organogenesis. Aberrant activation of hedgehog signaling leads to pathological consequences, including a variety of human tumors such as pancreatic cancer. Multiple lines of evidence indicate that blockade of this pathway with several small-molecule inhibitors can inhibit the development of pancreatic neoplasm. In addition, activated hedgehog signaling has been reported to be involved in fibrogenesis in many tissues, including the pancreas. Therefore, new therapeutic targets based on hedgehog signaling have attracted a great deal of attention to alleviate pancreatic diseases. In this review, we briefly discuss the recent advances in hedgehog signaling in pancreatic fibrogenesis and carcinogenesis and highlight new insights on their potential relationship with respect to the development of novel targeted therapies. PMID:26962810

  13. Distributed traffic signal control using fuzzy logic

    Science.gov (United States)

    Chiu, Stephen

    1992-01-01

    We present a distributed approach to traffic signal control, where the signal timing parameters at a given intersection are adjusted as functions of the local traffic condition and of the signal timing parameters at adjacent intersections. Thus, the signal timing parameters evolve dynamically using only local information to improve traffic flow. This distributed approach provides for a fault-tolerant, highly responsive traffic management system. The signal timing at an intersection is defined by three parameters: cycle time, phase split, and offset. We use fuzzy decision rules to adjust these three parameters based only on local information. The amount of change in the timing parameters during each cycle is limited to a small fraction of the current parameters to ensure smooth transition. We show the effectiveness of this method through simulation of the traffic flow in a network of controlled intersections.

  14. Fiber-optic lattice signal processing

    Science.gov (United States)

    Moslehi, B.; Goodman, J. W.; Shaw, H. J.; Tur, M.

    1984-07-01

    It is pointed out that fiber-optic signal processing devices can be constructed to perform various functions, such as convolution, correlation, matrix operations, and frequency filtering. Previous studies have concentrated on classical tapped-delay-line forms (transversal filters). The present investigation is concerned with different fiber-optic structures, taking into account lattice (or ladder) forms, which can be used as alternatives for performing optical signal processing. The elements to perform the various signal processing operations are considered along with fiber-optic lattice configurations. Aspects of mathematical analysis are discussed, taking into account Z-transform techniques, transfer-matrix and chain-matrix formulations, modern control theory formulations, and positive optical systems. Attention is given to time-domain signal processing applications, and frequency-domain signal processing applications.

  15. Optimal signal patterns for dynamical cellular communication

    CERN Document Server

    Hasegawa, Yoshihiko

    2015-01-01

    Cells transmit information via signaling pathways, using temporal dynamical patterns. As optimality with respect to environments is the universal principle in biological systems, organisms have acquired an optimal way of transmitting information. Here we obtain optimal dynamical signal patterns which can transmit information efficiently (low power) and reliably (high accuracy) using the optimal control theory. Adopting an activation-inactivation decoding network, we reproduced several dynamical patterns found in actual signals, such as steep, gradual and overshooting dynamics. Notably, when minimizing the power of the input signal, optimal signals exhibit the overshooting pattern, which is a biphasic pattern with transient and steady phases; this pattern is prevalent in actual dynamical patterns as it can be generated by an incoherent feed-forward loop (FFL), a common motif in biochemical networks. We also identified conditions when the three patterns, steep, gradual and overshooting, confer advantages.

  16. Surface electromyography signal processing and classification techniques.

    Science.gov (United States)

    Chowdhury, Rubana H; Reaz, Mamun B I; Ali, Mohd Alauddin Bin Mohd; Bakar, Ashrif A A; Chellappan, K; Chang, T G

    2013-09-17

    Electromyography (EMG) signals are becoming increasingly important in many applications, including clinical/biomedical, prosthesis or rehabilitation devices, human machine interactions, and more. However, noisy EMG signals are the major hurdles to be overcome in order to achieve improved performance in the above applications. Detection, processing and classification analysis in electromyography (EMG) is very desirable because it allows a more standardized and precise evaluation of the neurophysiological, rehabitational and assistive technological findings. This paper reviews two prominent areas; first: the pre-processing method for eliminating possible artifacts via appropriate preparation at the time of recording EMG signals, and second: a brief explanation of the different methods for processing and classifying EMG signals. This study then compares the numerous methods of analyzing EMG signals, in terms of their performance. The crux of this paper is to review the most recent developments and research studies related to the issues mentioned above.

  17. ROS and ROS-Mediated Cellular Signaling

    Directory of Open Access Journals (Sweden)

    Jixiang Zhang

    2016-01-01

    Full Text Available It has long been recognized that an increase of reactive oxygen species (ROS can modify the cell-signaling proteins and have functional consequences, which successively mediate pathological processes such as atherosclerosis, diabetes, unchecked growth, neurodegeneration, inflammation, and aging. While numerous articles have demonstrated the impacts of ROS on various signaling pathways and clarify the mechanism of action of cell-signaling proteins, their influence on the level of intracellular ROS, and their complex interactions among multiple ROS associated signaling pathways, the systemic summary is necessary. In this review paper, we particularly focus on the pattern of the generation and homeostasis of intracellular ROS, the mechanisms and targets of ROS impacting on cell-signaling proteins (NF-κB, MAPKs, Keap1-Nrf2-ARE, and PI3K-Akt, ion channels and transporters (Ca2+ and mPTP, and modifying protein kinase and Ubiquitination/Proteasome System.

  18. Comparison of Different ECG Signals on MATLAB

    Directory of Open Access Journals (Sweden)

    Rajan Chaudhary

    2013-03-01

    Full Text Available In this paper we discuss about biomedical engineering and then a brief description of ECG signal. We have generated a new method to compare different arrhythmic heart signals with normal sinus signals at MATLAB. This is making the comparison very easy. ECG is used to measure the rate and regularity of heartbeats, as well as the position and size of the chambers, the existence of any damage to the heart, and the effects of devices or drugs used to regulate the heart, such as a pacemaker. Uttermost ECGs are performed for diagnostic or research purposes on human hearts, but may also be performed on heart of animals, usually for diagnosis of heart abnormalities or research. Result obtained showing that Comparison of Normal (Sinus and Abnormal (arrhythmia ECG signal. Through this method we can compare any type of disordered signal of heart.

  19. Research on Portable Fatigue Signal Detection System

    Directory of Open Access Journals (Sweden)

    Bowen Li

    2013-07-01

    Full Text Available According to the characteristics of human pulse wave signals, the acquisition system acquisition system with excellent performance is designed, 16 bit MCU MSP430 with ultralow power is used to record, process and transmit the collected pulse wave signals. In order to make the hardware part satisfy acquisition requirements of pulse wave, the paper focuses on discussing composition, operating principle, analysis method and performance parameter of analog circuit. The software part makes use of the design tools of Matlab graphical user interface (GUI for designing pulse wave signal measurement system. The trial on intelligent fatigue test signal adopts relatively unique methods no matter in hardware circuit design or software algorithm process, which provides important and meaningful reference for objective and quantitative research on fatigue signal.

  20. Neural network signal understanding for instrumentation

    DEFF Research Database (Denmark)

    Pau, L. F.; Johansen, F. S.

    1990-01-01

    A report is presented on the use of neural signal interpretation theory and techniques for the purpose of classifying the shapes of a set of instrumentation signals, in order to calibrate devices, diagnose anomalies, generate tuning/settings, and interpret the measurement results. Neural signal...... understanding research is surveyed, and the selected implementation and its performance in terms of correct classification rates and robustness to noise are described. Formal results on neural net training time and sensitivity to weights are given. A theory for neural control using functional link nets is given......, and an explanation facility designed to help neural signal understanding is described. The results are compared to those obtained with a knowledge-based signal interpretation system using the same instrument and data...

  1. Energy Loss Signals in the ALICE TRD

    CERN Document Server

    Xian-Guo, Lu

    2013-01-01

    We present the energy loss measurements with the ALICE TRD in the $\\beta\\gamma$ range 1--10$^{4}$, where $\\beta=v/c$ and $\\gamma=1/\\sqrt{1-\\beta^2}$. The measurements are conducted in three different scenarios: 1) with pions and electrons from testbeams; 2) with protons, pions and electrons in proton-proton collisions at center-of-mass energy 7 TeV; 3) with muons detected in ALICE cosmic runs. In the testbeam and cosmic ray measurements, ionization energy loss (dE/dx) signal as well as ionization energy loss plus transition radiation (dE/dx+TR) signal are measured. With cosmic muons the onset of TR is observed. Signals from TeV cosmic muons are consistent with those from GeV electrons in the other measurements. Numerical descriptions of the signal spectra and the $\\beta\\gamma$-dependence of the most probable signals are also presented.

  2. One laser pulse generates two photoacoustic signals

    CERN Document Server

    Gao, Fei; Zheng, Yuanjin

    2016-01-01

    Photoacoustic sensing and imaging techniques have been studied widely to explore optical absorption contrast based on nanosecond laser illumination. In this paper, we report a long laser pulse induced dual photoacoustic (LDPA) nonlinear effect, which originates from unsatisfied stress and thermal confinements. Being different from conventional short laser pulse illumination, the proposed method utilizes a long square-profile laser pulse to induce dual photoacoustic signals. Without satisfying the stress confinement, the dual photoacoustic signals are generated following the positive and negative edges of the long laser pulse. More interestingly, the first expansion-induced photoacoustic signal exhibits positive waveform due to the initial sharp rising of temperature. On the contrary, the second contraction-induced photoacoustic signal exhibits exactly negative waveform due to the falling of temperature, as well as pulse-width-dependent, signal amplitude which is caused by the concurrent heat accumulation and ...

  3. Mathematical properties of a semi-classical signal analysis method: Noisy signal case

    KAUST Repository

    Liu, Dayan

    2012-08-01

    Recently, a new signal analysis method based on a semi-classical approach has been proposed [1]. The main idea in this method is to interpret a signal as a potential of a Schrodinger operator and then to use the discrete spectrum of this operator to analyze the signal. In this paper, we are interested in a mathematical analysis of this method in discrete case considering noisy signals. © 2012 IEEE.

  4. Conversion of phase-modulated signals to amplitude-modulated signals in SOAs due to mirror reflections

    DEFF Research Database (Denmark)

    Blaaberg, Søren; Mørk, Jesper

    2009-01-01

    We present theoretical results that show conversion of phase modulated signals to amplitude modulated signals in an SOA. Large-signal and small-signal calculations show significant conversion responses caused by even minute reflections at the end mirrors.......We present theoretical results that show conversion of phase modulated signals to amplitude modulated signals in an SOA. Large-signal and small-signal calculations show significant conversion responses caused by even minute reflections at the end mirrors....

  5. Silicon Photonics for Signal Processing of Tbit/s Serial Data Signals

    DEFF Research Database (Denmark)

    Oxenløwe, Leif Katsuo; Ji, Hua; Galili, Michael;

    2012-01-01

    In this paper, we describe our recent work on signal processing of terabit per second optical serial data signals using pure silicon waveguides. We employ nonlinear optical signal processing in nanoengineered silicon waveguides to perform demultiplexing and optical waveform sampling of 1.28-Tbit/...

  6. Ultra-high-speed optical signal processing of serial data signals

    DEFF Research Database (Denmark)

    Clausen, Anders; Mulvad, Hans Christian Hansen; Palushani, Evarist;

    2012-01-01

    To ensure that ultra high-speed serial data signals can be utilised in future optical communication networks, it is indispensable to have all-optical signal processing elements at our disposal. In this paper, the most recent advances in our use of non-linear materials incorporated in different...... function blocks for high-speed signal processing are reviewed....

  7. All-optical signal processing of OTDM and OFDM signals based on time-domain Optical Fourier Transformation

    DEFF Research Database (Denmark)

    Clausen, Anders; Guan, Pengyu; Mulvad, Hans Christian Hansen;

    2014-01-01

    All-optical time-domain Optical Fourier Transformation utilised for signal processing of ultra-high-speed OTDM signals and OFDM signals will be presented.......All-optical time-domain Optical Fourier Transformation utilised for signal processing of ultra-high-speed OTDM signals and OFDM signals will be presented....

  8. Electrochemical noise minimization using digital signal processing

    Directory of Open Access Journals (Sweden)

    Claudia Smaniotto Barin

    2004-01-01

    Full Text Available This work discusses electrochemical noise in low amplitude signals and reviews the bibliography on signal iltering methods used to reduce noise interference. One of these methods, the Singular Spectrum Analysis (SSA, is described in detail and used to filter some signals in electrostatic deposition experiments. This study also compares results from other filtering techniques such as moving average, Stavitsky-Golay and Fourier and Wavelet, and discusses the advantages and disadvantages of transforms. Results have shown that the SSA method is efficient, of easy applicability, and extremely important for the understanding of electrodeposition characteristics. In the Introduction of this work, the origin of the signals is discussed, and the advantages, problems and the noise filtering techniques related to electrical deposition through microelectrodes are presented. In the Theory section, the SSA method is described, and the reasons for using it with noisy signals are presented. In the Materials and Methods section, the equipment and software used for collecting and processing the signals are described briefly. Finally, in the Results section, the signals reconstructed through SSA, as well as those found in other filtering techniques are presented.

  9. Single-Molecule Imaging of Cellular Signaling

    Science.gov (United States)

    De Keijzer, Sandra; Snaar-Jagalska, B. Ewa; Spaink, Herman P.; Schmidt, Thomas

    Single-molecule microscopy is an emerging technique to understand the function of a protein in the context of its natural environment. In our laboratory this technique has been used to study the dynamics of signal transduction in vivo. A multitude of signal transduction cascades are initiated by interactions between proteins in the plasma membrane. These cascades start by binding a ligand to its receptor, thereby activating downstream signaling pathways which finally result in complex cellular responses. To fully understand these processes it is important to study the initial steps of the signaling cascades. Standard biological assays mostly call for overexpression of the proteins and high concentrations of ligand. This sets severe limits to the interpretation of, for instance, the time-course of the observations, given the large temporal spread caused by the diffusion-limited binding processes. Methods and limitations of single-molecule microscopy for the study of cell signaling are discussed on the example of the chemotactic signaling of the slime-mold Dictyostelium discoideum. Single-molecule studies, as reviewed in this chapter, appear to be one of the essential methodologies for the full spatiotemporal clarification of cellular signaling, one of the ultimate goals in cell biology.

  10. Photoacoustic imaging of voltage signals (Conference Presentation)

    Science.gov (United States)

    Rao, Bin; Zhang, Ruiying; Wang, Lihong V.

    2016-03-01

    Optical imaging of brain voltage signals is significantly limited in depth due to optical scattering and the absorptive property of brain tissue. Photoacoustic (PA) imaging promises to break this hard limit by utilizing both ballistic and diffused photons. To demonstrate the feasibility of PA, we used an in vivo mouse model. The brain cortex tissue was stained with dipicrylamine dye, electrically stimulated, and imaged with a customized dual-isosbestic-wavelength PA microscope (DIW-PAM). DIW-PAM separates voltage-induced PA signals from blood-induced PA signals and thereby allows recording the voltage response of mouse cortex tissue without interference from hemoglobin responses. The resting state PA voltage response signal exhibited a noise-like signal in the frequency domain. Upon 3 Hz electrical stimulation, the PA voltage response signal showed frequency peaks of 3.2 Hz and 6.3 Hz (Fig. 1). Although dipicrylamine dye is not fast enough for recording neuron action potentials, it served well for the purpose of this feasibility study. In conclusion, we successfully demonstrated in vivo photoacoustic imaging of mouse brain voltage signals for the first time. If a fast voltage-sensitive dye is available, using photoacoustic computed tomography (PACT) instead of PA microscopy could allow acquiring full-field PA action potential images at a speed limited only by the laser pulse repetition rate.

  11. Calibration of Galileo signals for time metrology.

    Science.gov (United States)

    Defraigne, Pascale; Aerts, Wim; Cerretto, Giancarlo; Cantoni, Elena; Sleewaegen, Jean-Marie

    2014-12-01

    Using global navigation satellite system (GNSS) signals for accurate timing and time transfer requires the knowledge of all electric delays of the signals inside the receiving system. GNSS stations dedicated to timing or time transfer are classically calibrated only for Global Positioning System (GPS) signals. This paper proposes a procedure to determine the hardware delays of a GNSS receiving station for Galileo signals, once the delays of the GPS signals are known. This approach makes use of the broadcast satellite inter-signal biases, and is based on the ionospheric delay measured from dual-frequency combinations of GPS and Galileo signals. The uncertainty on the so-determined hardware delays is estimated to 3.7 ns for each isolated code in the L5 frequency band, and 4.2 ns for the ionosphere-free combination of E1 with a code of the L5 frequency band. For the calibration of a time transfer link between two stations, another approach can be used, based on the difference between the common-view time transfer results obtained with calibrated GPS data and with uncalibrated Galileo data. It is shown that the results obtained with this approach or with the ionospheric method are equivalent.

  12. A special issue on photonic signal processing

    Institute of Scientific and Technical Information of China (English)

    Xinliang ZHANG; Jianping CHEN

    2011-01-01

    Photonic signal processing has been receiving increasing attention for about fifteen years.It would be enabling technology for next generation large capacity optical networks because it can avoid electronics bottleneck and decrease power consumption greatly.There are two main areas related to photonic signal processing.One topic is all-optical signal processing for digital bit sequence in optical network,such as all-optical wavelength conversion,alloptical logic operation,all-optical 3R regeneration,all-optical clock recovery,all-optical buffer,etc.The other topic is microwave photonic signal processing,such as microwave photonic filters,arbitrary waveform generation,RF signal generation,UWB signal generation,etc.However,there are still many problems to be solved before these functions could be used in optical networks.Researchers all over the world are concentrating on realizing photonic signal processing functions with some characteristics such as high operation speed and large bandwidth,flexible and multifunctional,potential integration.

  13. Calibration of Galileo signals for time metrology.

    Science.gov (United States)

    Defraigne, Pascale; Aerts, Wim; Cerretto, Giancarlo; Cantoni, Elena; Sleewaegen, Jean-Marie

    2014-12-01

    Using global navigation satellite system (GNSS) signals for accurate timing and time transfer requires the knowledge of all electric delays of the signals inside the receiving system. GNSS stations dedicated to timing or time transfer are classically calibrated only for Global Positioning System (GPS) signals. This paper proposes a procedure to determine the hardware delays of a GNSS receiving station for Galileo signals, once the delays of the GPS signals are known. This approach makes use of the broadcast satellite inter-signal biases, and is based on the ionospheric delay measured from dual-frequency combinations of GPS and Galileo signals. The uncertainty on the so-determined hardware delays is estimated to 3.7 ns for each isolated code in the L5 frequency band, and 4.2 ns for the ionosphere-free combination of E1 with a code of the L5 frequency band. For the calibration of a time transfer link between two stations, another approach can be used, based on the difference between the common-view time transfer results obtained with calibrated GPS data and with uncalibrated Galileo data. It is shown that the results obtained with this approach or with the ionospheric method are equivalent. PMID:25474773

  14. Adaptive wavelet Wiener filtering of ECG signals.

    Science.gov (United States)

    Smital, Lukáš; Vítek, Martin; Kozumplík, Jiří; Provazník, Ivo

    2013-02-01

    In this study, we focused on the reduction of broadband myopotentials (EMG) in ECG signals using the wavelet Wiener filtering with noise-free signal estimation. We used the dyadic stationary wavelet transform (SWT) in the Wiener filter as well as in estimating the noise-free signal. Our goal was to find a suitable filter bank and to choose other parameters of the Wiener filter with respect to the signal-to-noise ratio (SNR) obtained. Testing was performed on artificially noised signals from the standard CSE database sampled at 500 Hz. When creating an artificial interference, we started from the generated white Gaussian noise, whose power spectrum was modified according to a model of the power spectrum of an EMG signal. To improve the filtering performance, we used adaptive setting parameters of filtering according to the level of interference in the input signal. We were able to increase the average SNR of the whole test database by about 10.6 dB. The proposed algorithm provides better results than the classic wavelet Wiener filter. PMID:23192472

  15. Role of nitric oxide in actin depolymerization and programmed cell death induced by fusicoccin in sycamore (Acer pseudoplatanus) cultured cells.

    Science.gov (United States)

    Malerba, Massimo; Contran, Nicla; Tonelli, Mariagrazia; Crosti, Paolo; Cerana, Raffaella

    2008-06-01

    Programmed cell death (PCD) plays a vital role in plant development and is involved in defence mechanisms against biotic and abiotic stresses. Different forms of PCD have been described in plants on the basis of the cell organelle first involved. In sycamore (Acer pseudoplatanus L.) cultured cells, the phytotoxin fusicoccin (FC) induces cell death. However, only a fraction of the dead cells shows the typical hallmarks of animal apoptosis, including cell shrinkage, chromatin condensation, DNA fragmentation and release of cytochrome c from the mitochondrion. In this work, we show that the scavenging of nitric oxide (NO), produced in the presence of FC, by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) and rutin inhibits cell death without affecting DNA fragmentation and cytochrome c release. In addition, we show that FC induces a massive depolymerization of actin filaments that is prevented by the NO scavengers. Finally, the addition of actin-depolymerizing drugs induces PCD in control cells and overcomes the inhibiting effect of cPTIO on FC-induced cell death. Vice versa, the addition of actin-stabilizing drugs to FC-treated cells partially inhibits the phytotoxin-induced PCD. These results suggest that besides an apoptotic-like form of PCD involving the release of cytochrome c, FC induces at least another form of cell death, likely mediated by NO and independent of cytochrome c release, and they make it tempting to speculate that changes in actin cytoskeleton are involved in this form of PCD.

  16. Determination of Cell Death Induced by Lovastatin on Human Colon Cell Line HT29 Using the Comet Assay

    OpenAIRE

    Jafari, Marzieh; Rezaei, Mohsen; Kalantari, Heibatullah; Hashemitabar, Mahmoud

    2013-01-01

    Background Apoptosis or programmed cell death is an essential process for elimination of damaged cells. Also, induction of apoptosis is fundamental for treating cancer. Screening for agents that induce apoptosis in tumor cells help in the development of novel agents for cancer treatment. Numerous studies suggest that the exposure of tumor cells to statins can lead to cell death via two separate processes: apoptosis or necrosis. Severe fragmentation of DNA during apoptosis can be readily measu...

  17. CYTOTOXICITY AND MODE OF CELL DEATH INDUCED BY TRIPHENYLTIN (IV) COMPOUNDS IN VITRO

    OpenAIRE

    Normah Awang; Zalila Abdul Aziz; Nurul Farahana Kamaludin; Kok Meng Chan

    2014-01-01

    A series of newly synthesized organotin (IV) with N-alkyl-N-phenyldithiocarbamate ligands namely triphenyltin (IV) ethylphenyldithiocarbamate (compound 1) and triphenyltin (IV) butylphenyldithiocarbamate (compound 2) were assessed for their cytotoxic effect against HT-29 human colon adenocarcinoma cells and human CCD-18Co normal colon cells. The cytotoxicity of these organotins in both cells was assessed using 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazholium bromide (MTT) assay upon 24 ...

  18. Synergistic Effect of H2O2 and NO2 in Cell Death Induced by Cold Atmospheric He Plasma.

    Science.gov (United States)

    Girard, Pierre-Marie; Arbabian, Atousa; Fleury, Michel; Bauville, Gérard; Puech, Vincent; Dutreix, Marie; Sousa, João Santos

    2016-01-01

    Cold atmospheric pressure plasmas (CAPPs) have emerged over the last decade as a new promising therapy to fight cancer. CAPPs' antitumor activity is primarily due to the delivery of reactive oxygen and nitrogen species (RONS), but the precise determination of the constituents linked to this anticancer process remains to be done. In the present study, using a micro-plasma jet produced in helium (He), we demonstrate that the concentration of H2O2, NO2(-) and NO3(-) can fully account for the majority of RONS produced in plasma-activated buffer. The role of these species on the viability of normal and tumour cell lines was investigated. Although the degree of sensitivity to H2O2 is cell-type dependent, we show that H2O2 alone cannot account for the toxicity of He plasma. Indeed, NO2(-), but not NO3(-), acts in synergy with H2O2 to enhance cell death in normal and tumour cell lines to a level similar to that observed after plasma treatment. Our findings suggest that the efficiency of plasma treatment strongly depends on the combination of H2O2 and NO2(-) in determined concentrations. We also show that the interaction of the He plasma jet with the ambient air is required to generate NO2(-) and NO3(-) in solution.

  19. Ursodeoxycholic acid suppresses mitochondria-dependent programmed cell death induced by sodium nitroprusside in SH-SY5Y cells

    International Nuclear Information System (INIS)

    Although ursodeoxycholic acid (UDCA) and its highly water-soluble formula (Yoo's solution; YS) have been shown to prevent neuronal damage, the effects of UDCA or YS against Parkinson's disease (PD)-related dopaminergic cell death has not been studied. This study investigated the protective effects of UDCA and YS on sodium nitroprusside (SNP)-induced cytotoxicity in human dopaminergic SH-SY5Y cells. Both UDCA (50–200 μM) and YS (100–200 μM) dose-dependently prevented SNP (1 mM)-induced cell death. Results showed that both UDCA and YS effectively attenuated the production of total reactive oxygen species (ROS), peroxynitrite (ONOO−) and nitric oxide (NO), and markedly inhibited the mitochondrial membrane potential (MMP) loss and intracellular reduced glutathione (GSH) depletion. SNP-induced programmed cell death events, such as nuclear fragmentation, caspase-3/7 and -9 activation, Bcl-2/Bax ratio decrease, and cytochrome c release, were significantly attenuated by both UDCA and YS. Furthermore, selective inhibitor of phosphatidylinositiol-3-kinase (PI3K), LY294002, and Akt/PKB inhibitor, triciribine, reversed the preventive effects of UDCA on the SNP-induced cytotoxicity and Bax translocation. These results suggest that UDCA can protect SH-SY5Y cells under programmed cell death process by regulating PI3K-Akt/PKB pathways.

  20. Synergistic Effect of H2O2 and NO2 in Cell Death Induced by Cold Atmospheric He Plasma

    Science.gov (United States)

    Girard, Pierre-Marie; Arbabian, Atousa; Fleury, Michel; Bauville, Gérard; Puech, Vincent; Dutreix, Marie; Sousa, João Santos

    2016-01-01

    Cold atmospheric pressure plasmas (CAPPs) have emerged over the last decade as a new promising therapy to fight cancer. CAPPs’ antitumor activity is primarily due to the delivery of reactive oxygen and nitrogen species (RONS), but the precise determination of the constituents linked to this anticancer process remains to be done. In the present study, using a micro-plasma jet produced in helium (He), we demonstrate that the concentration of H2O2, NO2− and NO3− can fully account for the majority of RONS produced in plasma-activated buffer. The role of these species on the viability of normal and tumour cell lines was investigated. Although the degree of sensitivity to H2O2 is cell-type dependent, we show that H2O2 alone cannot account for the toxicity of He plasma. Indeed, NO2−, but not NO3−, acts in synergy with H2O2 to enhance cell death in normal and tumour cell lines to a level similar to that observed after plasma treatment. Our findings suggest that the efficiency of plasma treatment strongly depends on the combination of H2O2 and NO2− in determined concentrations. We also show that the interaction of the He plasma jet with the ambient air is required to generate NO2− and NO3− in solution. PMID:27364563