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Sample records for cancer redox steering

  1. CCCT - NCORP Cancer Control Steering Committees

    Science.gov (United States)

    The National Community Oncology Research Program (NCORP) Steering Committees review concepts for clinical trials to control cancer symptoms and cancer treatment side effects, and concepts for studies of cancer care delivery.

  2. CCCT - NCTN Steering Committees - Gynecologic Cancers

    Science.gov (United States)

    The Gynecologic Cancers Steering Committee evaluates and prioritizes concepts for phase 2 and 3 clinical trials in adult gynecologic cancers. The GCSC is also intent on fostering collaboration with international groups and institutions conducting trials.

  3. Redox Regulation in Cancer Stem Cells

    Directory of Open Access Journals (Sweden)

    Shijie Ding

    2015-01-01

    Full Text Available Reactive oxygen species (ROS and ROS-dependent (redox regulation signaling pathways and transcriptional activities are thought to be critical in stem cell self-renewal and differentiation during growth and organogenesis. Aberrant ROS burst and dysregulation of those ROS-dependent cellular processes are strongly associated with human diseases including many cancers. ROS levels are elevated in cancer cells partially due to their higher metabolism rate. In the past 15 years, the concept of cancer stem cells (CSCs has been gaining ground as the subpopulation of cancer cells with stem cell-like properties and characteristics have been identified in various cancers. CSCs possess low levels of ROS and are responsible for cancer recurrence after chemotherapy or radiotherapy. Unfortunately, how CSCs control ROS production and scavenging and how ROS-dependent signaling pathways contribute to CSCs function remain poorly understood. This review focuses on the role of redox balance, especially in ROS-dependent cellular processes in cancer stem cells (CSCs. We updated recent advances in our understanding of ROS generation and elimination in CSCs and their effects on CSC self-renewal and differentiation through modulating signaling pathways and transcriptional activities. The review concludes that targeting CSCs by manipulating ROS metabolism/dependent pathways may be an effective approach for improving cancer treatment.

  4. Redox subpopulations and the risk of cancer progression: a new method for characterizing redox heterogeneity

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    Xu, He N.; Li, Lin Z.

    2016-02-01

    It has been shown that a malignant tumor is akin to a complex organ comprising of various cell populations including tumor cells that are genetically, metabolically and functionally different. Our redox imaging data have demonstrated intra-tumor redox heterogeneity in all mouse xenografts derived from human melanomas, breast, prostate, and colon cancers. Based on the signals of NADH and oxidized flavoproteins (Fp, including flavin adenine dinucleotide (FAD)) and their ratio, i.e., the redox ratio, which is an indicator of mitochondrial metabolic status, we have discovered several distinct redox subpopulations in xenografts of breast tumors potentially recapitulating functional/metabolic heterogeneity within the tumor. Furthermore, xenografts of breast tumors with higher metastatic potential tend to have a redox subpopulation whose redox ratio is significantly different from that of tumors with lower metastatic potential and usually have a bi-modal distribution of the redox ratio. The redox subpopulations from human breast cancer samples can also be very complex with multiple subpopulations as determined by fitting the redox ratio histograms with multi- Gaussian functions. In this report, we present a new method for identifying the redox subpopulations within individual breast tumor xenografts and human breast tissues, which may be used to differentiate between breast cancer and normal tissue and among breast cancer with different risks of progression.

  5. Redox regulation of cancer metastasis: molecular signaling and therapeutic opportunities.

    Science.gov (United States)

    Yang, Wenyong; Zou, Linzhi; Huang, Canhua; Lei, Yunlong

    2014-08-01

    Cancer metastasis is the major cause of cancer-related mortality. Accumulated evidence has shown that high-metastasis potential cancer cells have more reactive oxygen species (ROS) accumulation compared with low-metastasis potential cancer cells. ROS can function as second messengers to regulate multiple cancer metastasis-related signaling pathways via reversible oxidative posttranslational modifications of cysteine in key redox-sensitive proteins, which leads to the structural and functional change of these proteins. Because ROS can promote cancer metastasis, therapeutic strategies aiming at inducing/reducing cellular ROS level or targeting redox sensors involved in metastasis hold great potential in developing new efficient approaches for anticancer therapy. In this review, we summarize recent findings on regulation of tumor metastasis by key redox sensors and describe the potential of targeting redox signaling pathways for cancer therapy.

  6. Redox regulation in cancer stem cells

    Science.gov (United States)

    Reactive oxygen species (ROS) and ROS-dependent (redox regulation) signaling pathways and transcriptional activities are thought to be critical in stem cell self-renewal and differentiation during growth and organogenesis. Aberrant ROS burst and dysregulation of those ROS-dependent cellular processe...

  7. TCA Cycle Defects and Cancer: When Metabolism Tunes Redox State

    Directory of Open Access Journals (Sweden)

    Simone Cardaci

    2012-01-01

    Full Text Available Inborn defects of the tricarboxylic acid (TCA cycle enzymes have been known for more than twenty years. Until recently, only recessive mutations were described which, although resulted in severe multisystem syndromes, did not predispose to cancer onset. In the last ten years, a causal role in carcinogenesis has been documented for inherited and acquired alterations in three TCA cycle enzymes, succinate dehydrogenase (SDH, fumarate hydratase (FH, and isocitrate dehydrogenase (IDH, pointing towards metabolic alterations as the underlying hallmark of cancer. This paper summarizes the neoplastic alterations of the TCA cycle enzymes focusing on the generation of pseudohypoxic phenotype and the alteration of epigenetic homeostasis as the main tumor-promoting effects of the TCA cycle affecting defects. Moreover, we debate on the ability of these mutations to affect cellular redox state and to promote carcinogenesis by impacting on redox biology.

  8. The redox biology network in cancer pathophysiology and therapeutics

    Directory of Open Access Journals (Sweden)

    Gina Manda

    2015-08-01

    Full Text Available The review pinpoints operational concepts related to the redox biology network applied to the pathophysiology and therapeutics of solid tumors. A sophisticated network of intrinsic and extrinsic cues, integrated in the tumor niche, drives tumorigenesis and tumor progression. Critical mutations and distorted redox signaling pathways orchestrate pathologic events inside cancer cells, resulting in resistance to stress and death signals, aberrant proliferation and efficient repair mechanisms. Additionally, the complex inter-cellular crosstalk within the tumor niche, mediated by cytokines, redox-sensitive danger signals (HMGB1 and exosomes, under the pressure of multiple stresses (oxidative, inflammatory, metabolic, greatly contributes to the malignant phenotype. The tumor-associated inflammatory stress and its suppressive action on the anti-tumor immune response are highlighted. We further emphasize that ROS may act either as supporter or enemy of cancer cells, depending on the context. Oxidative stress-based therapies, such as radiotherapy and photodynamic therapy, take advantage of the cytotoxic face of ROS for killing tumor cells by a non-physiologically sudden, localized and intense oxidative burst. The type of tumor cell death elicited by these therapies is discussed. Therapy outcome depends on the differential sensitivity to oxidative stress of particular tumor cells, such as cancer stem cells, and therefore co-therapies that transiently down-regulate their intrinsic antioxidant system hold great promise. We draw attention on the consequences of the damage signals delivered by oxidative stress-injured cells to neighboring and distant cells, and emphasize the benefits of therapeutically triggered immunologic cell death in metastatic cancer. An integrative approach should be applied when designing therapeutic strategies in cancer, taking into consideration the mutational, metabolic, inflammatory and oxidative status of tumor cells, cellular

  9. Redox biology in normal cells and cancer: restoring function of the redox/Fyn/c-Cbl pathway in cancer cells offers new approaches to cancer treatment.

    Science.gov (United States)

    Noble, Mark; Mayer-Pröschel, Margot; Li, Zaibo; Dong, Tiefei; Cui, Wanchang; Pröschel, Christoph; Ambeskovic, Ibro; Dietrich, Joerg; Han, Ruolan; Yang, Yin Miranda; Folts, Christopher; Stripay, Jennifer; Chen, Hsing-Yu; Stevens, Brett M

    2015-02-01

    This review discusses a unique discovery path starting with novel findings on redox regulation of precursor cell and signaling pathway function and identification of a new mechanism by which relatively small changes in redox status can control entire signaling networks that regulate self-renewal, differentiation, and survival. The pathway central to this work, the redox/Fyn/c-Cbl (RFC) pathway, converts small increases in oxidative status to pan-activation of the c-Cbl ubiquitin ligase, which controls multiple receptors and other proteins of central importance in precursor cell and cancer cell function. Integration of work on the RFC pathway with attempts to understand how treatment with systemic chemotherapy causes neurological problems led to the discovery that glioblastomas (GBMs) and basal-like breast cancers (BLBCs) inhibit c-Cbl function through altered utilization of the cytoskeletal regulators Cool-1/βpix and Cdc42, respectively. Inhibition of these proteins to restore normal c-Cbl function suppresses cancer cell division, increases sensitivity to chemotherapy, disrupts tumor-initiating cell (TIC) activity in GBMs and BLBCs, controls multiple critical TIC regulators, and also allows targeting of non-TICs. Moreover, these manipulations do not increase chemosensitivity or suppress division of nontransformed cells. Restoration of normal c-Cbl function also allows more effective harnessing of estrogen receptor-α (ERα)-independent activities of tamoxifen to activate the RFC pathway and target ERα-negative cancer cells. Our work thus provides a discovery strategy that reveals mechanisms and therapeutic targets that cannot be deduced by standard genetics analyses, which fail to reveal the metabolic information, isoform shifts, protein activation, protein complexes, and protein degradation critical to our discoveries.

  10. Strategic planning by the palliative care steering committee of the Middle East Cancer Consortium.

    Science.gov (United States)

    Moore, Shannon Y; Pirrello, Rosene D; Christianson, Sonya K; Ferris, Frank D

    2011-04-01

    High quality comprehensive palliative care is a critical need for millions of patients and families, but remains only a dream in many parts of the world. The failure to do a strategic planning process is one obstacle to advancing education and pain prevention and relief. The Middle Eastern Cancer Consortium Steering Committee attendees completed an initial strategic planning process and identified "developmental steps" to advance palliative care. Underscoring the multi-disciplinary nature of comprehensive palliative care, discipline-specific planning was done (adult and pediatric cancer and medicine, pharmacy, nursing) in a separate process from country-specific planning. Delineating the layers of intersection and differences between disciplines and countries was very powerful. Finding the common strengths and weaknesses in the status quo creates the potential for a more powerful regional response to the palliative care needs. Implementing and refining these preliminary strategic plans will augment and align the efforts to advance palliative care education and pain management in the Middle East. The dream to prevent and relieve suffering for millions of patients with advanced disease will become reality with a powerful strategic planning process well implemented.

  11. Redox Regulation in Cancer: A Double-edged Sword with Therapeutic Potential

    Directory of Open Access Journals (Sweden)

    Asha Acharya

    2010-01-01

    Full Text Available Oxidative stress, implicated in the etiology of cancer, results from an imbalance in the production of reactive oxygen species (ROS and cell’s own antioxidant defenses. ROS deregulate the redox homeostasis and promote tumor formation by initiating an aberrant induction of signaling networks that cause tumorigenesis. Ultraviolet (UV exposures, γ-radiation and other environmental carcinogens generate ROS in the cells, which can exert apoptosis in the tumors, thereby killing the malignant cells or induce the progression of the cancer growth by blocking cellular defense system. Cancer stem cells take the advantage of the aberrant redox system and spontaneously proliferate. Oxidative stress and gene-environment interactions play a significant role in the development of breast, prostate, pancreatic and colon cancer. Prolonged lifetime exposure to estrogen is associated with several kinds of DNA damage. Oxidative stress and estrogen receptor-associated proliferative changes are suggested to play important roles in estrogen-induced breast carcinogenesis. BRCA1, a tumor suppressor against hormone responsive cancers such as breast and prostate cancer, plays a significant role in inhibiting ROS and estrogen mediated DNA damage; thereby regulate the redox homeostasis of the cells. Several transcription factors and tumor suppressors are involved during stress response such as Nrf2, NFκB and BRCA1. A promising strategy for targeting redox status of the cells is to use readily available natural substances from vegetables, fruits, herbs and spices. Many of the phytochemicals have already been identified to have chemopreventive potential, capable of intervening in carcinogenesis.

  12. Redox regulation in cancer: a double-edged sword with therapeutic potential.

    Science.gov (United States)

    Acharya, Asha; Das, Ila; Chandhok, Des; Saha, Tapas

    2010-01-01

    Oxidative stress, implicated in the etiology of cancer, results from an imbalance in the production of reactive oxygen species (ROS) and cell's own antioxidant defenses. ROS deregulate the redox homeostasis and promote tumor formation by initiating an aberrant induction of signaling networks that cause tumorigenesis. Ultraviolet (UV) exposures, gamma-radiation and other environmental carcinogens generate ROS in the cells, which can exert apoptosis in the tumors, thereby killing the malignant cells or induce the progression of the cancer growth by blocking cellular defense system. Cancer stem cells take the advantage of the aberrant redox system and spontaneously proliferate. Oxidative stress and gene-environment interactions play a significant role in the development of breast, prostate, pancreatic and colon cancer. Prolonged lifetime exposure to estrogen is associated with several kinds of DNA damage. Oxidative stress and estrogen receptor-associated proliferative changes are suggested to play important roles in estrogen-induced breast carcinogenesis. BRCA1, a tumor suppressor against hormone responsive cancers such as breast and prostate cancer, plays a significant role in inhibiting ROS and estrogen mediated DNA damage; thereby regulate the redox homeostasis of the cells. Several transcription factors and tumor suppressors are involved during stress response such as Nrf2, NF-kappaB and BRCA1. A promising strategy for targeting redox status of the cells is to use readily available natural substances from vegetables, fruits, herbs and spices. Many of the phytochemicals have already been identified to have chemopreventive potential, capable of intervening in carcinogenesis.

  13. Specific point mutations in key redox enzymes are associated with chemoresistance in epithelial ovarian cancer.

    Science.gov (United States)

    Fletcher, Nicole M; Belotte, Jimmy; Saed, Mohammed G; Memaj, Ira; Diamond, Michael P; Morris, Robert T; Saed, Ghassan M

    2017-01-01

    Oxidative stress plays an important role in the pathophysiology of ovarian cancer. Resistance to chemotherapy presents a significant challenge for ovarian cancer treatment. Specific single nucleotide polymorphisms (SNPs) in key redox enzymes have been associated with ovarian cancer survival and progression. The objective of this study was to determine whether chemotherapy induces point mutations in key redox enzymes that lead to the acquisition of chemoresistance in epithelial ovarian cancer (EOC). Human EOC cell lines and their chemoresistant counterpart were utilized for this study. Specific SNPs in key redox enzymes were analyzed by TaqMan SNP Genotyping. Activities and levels of key redox enzymes were determined by real-time RT-PCR, ELISA and a greiss assay. Point mutations in key redox enzymes were introduced into sensitive EOC cells via the CRISPR/Cas9 system. Cell viability and IC50 for cisplatin were determined by the MTT Cell Proliferation Assay. Data was analyzed with SPSS using Student's two-tailed t-tests and One-way ANOVA followed by Dunnett's or Tukey's post hoc tests, penhancement in oxidative stress as compared to sensitive counterparts. Additionally, chemoresistant EOC cells manifested specific point mutations, which are associated with altered enzymatic activity, in key redox enzymes that are not detected in sensitive counterparts. Supplementation of an antioxidant was able to successfully sensitize EOC cells to chemotherapeutics. Causality was established by the induction of these point mutations in sensitive EOC cells, which resulted in a significant increase in the level of chemoresistance. These findings indicate that chemotherapy induces specific point mutations in key redox enzymes that contribute to the acquisition of chemoresistance in EOC cells, highlighting a potential novel mechanism. Identification of targets for chemoresistance with either biomarker and/or screening potential will have a significant impact for the treatment of this

  14. Thioredoxin-mediated redox regulation of resistance to endocrine therapy in breast cancer.

    Science.gov (United States)

    Penney, Rosalind Brigham; Roy, Deodutta

    2013-08-01

    Resistance to endocrine therapy in breast carcinogenesis due to the redox regulation of the signal transduction system by reactive oxygen species (ROS) is the subject of this review article. Both antiestrogens and aromatase inhibitors are thought to prevent cancer through modulating the estrogen receptor function, but other mechanisms cannot be ruled out as these compounds also block metabolism and redox cycling of estrogen and are free radical scavengers. Endocrine therapeutic agents, such as, tamoxifen and other antiestrogens, and the aromatase inhibitor, exemestane, are capable of producing ROS. Aggressive breast cancer cells have high oxidative stress and chronic treatment with exemestane, fulvestrant or tamoxifen may add additional ROS stress. Breast cancer cells receiving long-term antiestrogen treatment appear to adapt to this increased persistent level of ROS. This, in turn, may lead to the disruption of reversible redox signaling that involves redox-sensitive phosphatases, protein kinases, such as, ERK and AKT, and transcription factors, such as, AP-1, NRF-1 and NF-κB. Thioredoxin modulates the expression of estrogen responsive genes through modulating the production of H2O2 in breast cancer cells. Overexpressing thioredoxine reductase 2 and reducing oxidized thioredoxin restores tamoxifen sensitivity to previously resistant breast cancer cells. In summary, it appears that resistance to endocrine therapy may be mediated, in part, by ROS-mediated dysregulation of both estrogen-dependent and estrogen-independent redox-sensitive signaling pathways. Further studies are needed to define the mechanism of action of thioredoxin modifiers, and their effect on the redox regulation that contributes to restoring the antiestrogen-mediated signal transduction system and growth inhibitory action.

  15. Redox Homeostasis and Cellular Antioxidant Systems: Crucial Players in Cancer Growth and Therapy

    Directory of Open Access Journals (Sweden)

    Barbara Marengo

    2016-01-01

    Full Text Available Reactive oxygen species (ROS and their products are components of cell signaling pathways and play important roles in cellular physiology and pathophysiology. Under physiological conditions, cells control ROS levels by the use of scavenging systems such as superoxide dismutases, peroxiredoxins, and glutathione that balance ROS generation and elimination. Under oxidative stress conditions, excessive ROS can damage cellular proteins, lipids, and DNA, leading to cell damage that may contribute to carcinogenesis. Several studies have shown that cancer cells display an adaptive response to oxidative stress by increasing expression of antioxidant enzymes and molecules. As a double-edged sword, ROS influence signaling pathways determining beneficial or detrimental outcomes in cancer therapy. In this review, we address the role of redox homeostasis in cancer growth and therapy and examine the current literature regarding the redox regulatory systems that become upregulated in cancer and their role in promoting tumor progression and resistance to chemotherapy.

  16. Redox Homeostasis and Cellular Antioxidant Systems: Crucial Players in Cancer Growth and Therapy.

    Science.gov (United States)

    Marengo, Barbara; Nitti, Mariapaola; Furfaro, Anna Lisa; Colla, Renata; Ciucis, Chiara De; Marinari, Umberto Maria; Pronzato, Maria Adelaide; Traverso, Nicola; Domenicotti, Cinzia

    2016-01-01

    Reactive oxygen species (ROS) and their products are components of cell signaling pathways and play important roles in cellular physiology and pathophysiology. Under physiological conditions, cells control ROS levels by the use of scavenging systems such as superoxide dismutases, peroxiredoxins, and glutathione that balance ROS generation and elimination. Under oxidative stress conditions, excessive ROS can damage cellular proteins, lipids, and DNA, leading to cell damage that may contribute to carcinogenesis. Several studies have shown that cancer cells display an adaptive response to oxidative stress by increasing expression of antioxidant enzymes and molecules. As a double-edged sword, ROS influence signaling pathways determining beneficial or detrimental outcomes in cancer therapy. In this review, we address the role of redox homeostasis in cancer growth and therapy and examine the current literature regarding the redox regulatory systems that become upregulated in cancer and their role in promoting tumor progression and resistance to chemotherapy.

  17. Redox Proteomics Sheds Light on Photodynamic Treatment of Cancer

    NARCIS (Netherlands)

    Tsaytler, P.A.

    2009-01-01

    Cancer is the second most common cause of death among humans in the world, exceeded only by heart disease. One of the promising modalities for the treatment of cancer is photodynamic therapy (PDT). It is based on the concept that (1) certain light-sensitive compounds (photosensitizers) can be locali

  18. Peroxiredoxin II Is Essential for Maintaining Stemness by Redox Regulation in Liver Cancer Cells.

    Science.gov (United States)

    Kwon, Taeho; Bak, Yesol; Park, Young-Ho; Jang, Gyu-Beom; Nam, Jeong-Seok; Yoo, Jeong Eun; Park, Young Nyun; Bak, In Seon; Kim, Jin-Man; Yoon, Do-Young; Yu, Dae-Yeul

    2016-05-01

    Redox regulation in cancer stem cells (CSCs) is viewed as a good target for cancer therapy because redox status plays an important role in cancer stem-cell maintenance. Here, we investigated the role of Peroxiredoxin II (Prx II), an antioxidant enzyme, in association with maintenance of liver CSCs. Our study demonstrates that Prx II overexpressed in liver cancer cells has high potential for self-renewal activity. Prx II expression significantly corelated with expression of epithelial-cell adhesion molecules (EpCAM) and cytokerain 19 in liver cancer tissues of hepatocellular carcinoma (HCC) patients. Downregulation of Prx II in Huh7 cells with treatment of siRNA reduced expression of EpCAM and CD133 as well as Sox2 in accordance with increased ROS and apoptosis, which were reversed in Huh7-hPrx II cells. Huh7-hPrx II cells exhibited strong sphere-formation activity compared with mock cells. Vascular endothelial growth factor (VEGF) exposure enhanced sphere formation, cell-surface expression of EpCAM and CD133, and pSTAT3 along with activation of VEGF receptor 2 in Huh7-hPrx II cells. The result also emerged in Huh7-H-ras(G12V) and SK-HEP-1-H-ras(G12V) cells with high-level expression of Prx II. Prx II was involved in regulation of VEGF driving cancer stem cells through VEGFR-2/STAT3 signaling to upregulate Bmi1 and Sox2. In addition, knockdown of Prx II in Huh7-H-ras(G12V) cells showed significant reduction in cell migration in vitro and in tumorigenic potential in vivo. Taken together, all the results demonstrated that Prx II plays a key role in the CSC self-renewal of HCC cells through redox regulation. Stem Cells 2016;34:1188-1197.

  19. Nitric oxide-releasing prodrug triggers cancer cell death through deregulation of cellular redox balance

    Directory of Open Access Journals (Sweden)

    Anna E. Maciag

    2013-01-01

    Full Text Available JS-K is a nitric oxide (NO-releasing prodrug of the O2-arylated diazeniumdiolate family that has demonstrated pronounced cytotoxicity and antitumor properties in a variety of cancer models both in vitro and in vivo. The current study of the metabolic actions of JS-K was undertaken to investigate mechanisms of its cytotoxicity. Consistent with model chemical reactions, the activating step in the metabolism of JS-K in the cell is the dearylation of the diazeniumdiolate by glutathione (GSH via a nucleophilic aromatic substitution reaction. The resulting product (CEP/NO anion spontaneously hydrolyzes, releasing two equivalents of NO. The GSH/GSSG redox couple is considered to be the major redox buffer of the cell, helping maintain a reducing environment under basal conditions. We have quantified the effects of JS-K on cellular GSH content, and show that JS-K markedly depletes GSH, due to JS-K's rapid uptake and cascading release of NO and reactive nitrogen species. The depletion of GSH results in alterations in the redox potential of the cellular environment, initiating MAPK stress signaling pathways, and inducing apoptosis. Microarray analysis confirmed signaling gene changes at the transcriptional level and revealed alteration in the expression of several genes crucial for maintenance of cellular redox homeostasis, as well as cell proliferation and survival, including MYC. Pre-treating cells with the known GSH precursor and nucleophilic reducing agent N-acetylcysteine prevented the signaling events that lead to apoptosis. These data indicate that multiplicative depletion of the reduced glutathione pool and deregulation of intracellular redox balance are important initial steps in the mechanism of JS-K's cytotoxic action.

  20. Redox regulation of tumor suppressor PTEN in cancer and aging (Review).

    Science.gov (United States)

    Kitagishi, Yasuko; Matsuda, Satoru

    2013-03-01

    Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) has been shown to act as a tumor suppressor whose function includes important roles in regulating oxidative stress, indicating a potential role in oxidative damage-associated cancer. Accumulating evidence has revealed that PTEN also acts as a pivotal determinant of cell fate, regarding senescence and apoptosis, which is mediated by intracellular reactive oxygen species (ROS) generation. Cells are continuously exposed to ROS, which represent mutagens and are thought to be a major contributor to cancer and the aging process. Therefore, cellular ROS sensing and metabolism are firmly regulated by a variety of proteins involved in the redox mechanism. In this review, PTEN and the roles of oxidative stress in phosphoinositide-3 kinase/AKT signaling are summarized with a focus on the links between the pathways and ROS in cancer and aging.

  1. Overview of the Role of Vanillin on Redox Status and Cancer Development

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    Daniel Pereira Bezerra

    2016-01-01

    Full Text Available Bioactive natural products play critical roles in modern drug development, especially anticancer agents. It has been widely reported that various pharmacological activities of such compounds are related to their antioxidant properties. Vanillin is a natural substance widely found in many plant species and often used in beverages, foods, cosmetics, and pharmaceutical products. Antioxidant and anticancer potential have been described for this compound. Considering the importance of vanillin in the area of human health and food and pharmaceuticals sectors, in this review, we discuss the role of vanillin on redox status and its potential contribution to the prevention and the treatment of cancer.

  2. Overview of the Role of Vanillin on Redox Status and Cancer Development

    Science.gov (United States)

    Bezerra, Daniel Pereira; Soares, Anne Karine Nascimento

    2016-01-01

    Bioactive natural products play critical roles in modern drug development, especially anticancer agents. It has been widely reported that various pharmacological activities of such compounds are related to their antioxidant properties. Vanillin is a natural substance widely found in many plant species and often used in beverages, foods, cosmetics, and pharmaceutical products. Antioxidant and anticancer potential have been described for this compound. Considering the importance of vanillin in the area of human health and food and pharmaceuticals sectors, in this review, we discuss the role of vanillin on redox status and its potential contribution to the prevention and the treatment of cancer. PMID:28077989

  3. Steering handbook

    CERN Document Server

    Pfeffer, Peter

    2017-01-01

    This edited volume presents basic principles as well as advanced concepts of the computational modeling of steering systems. Moreover, the book includes the components and functionalities of modern steering system, which are presented comprehensively and in a practical way. The book is written by more than 15 leading experts from the automotive industry and its components suppliers. The target audience primarily comprises practicing engineers, developers, researchers as well as graduate students who want to specialize in this field.

  4. Cancer Therapy by Catechins Involves Redox Cycling of Copper Ions and Generation of Reactive Oxygen species.

    Science.gov (United States)

    Farhan, Mohd; Khan, Husain Yar; Oves, Mohammad; Al-Harrasi, Ahmed; Rehmani, Nida; Arif, Hussain; Hadi, Sheikh Mumtaz; Ahmad, Aamir

    2016-02-04

    Catechins, the dietary phytochemicals present in green tea and other beverages, are considered to be potent inducers of apoptosis and cytotoxicity to cancer cells. While it is believed that the antioxidant properties of catechins and related dietary agents may contribute to lowering the risk of cancer induction by impeding oxidative injury to DNA, these properties cannot account for apoptosis induction and chemotherapeutic observations. Catechin (C), epicatechin (EC), epigallocatechin (EGC) and epigallocatechin-3-gallate (EGCG) are the four major constituents of green tea. In this article, using human peripheral lymphocytes and comet assay, we show that C, EC, EGC and EGCG cause cellular DNA breakage and can alternatively switch to a prooxidant action in the presence of transition metals such as copper. The cellular DNA breakage was found to be significantly enhanced in the presence of copper ions. Catechins were found to be effective in providing protection against oxidative stress induced by tertbutylhydroperoxide, as measured by oxidative DNA breakage in lymphocytes. The prooxidant action of catechins involved production of hydroxyl radicals through redox recycling of copper ions. We also determined that catechins, particularly EGCG, inhibit proliferation of breast cancer cell line MDA-MB-231 leading to a prooxidant cell death. Since it is well established that tissue, cellular and serum copper levels are considerably elevated in various malignancies, cancer cells would be more subject to redox cycling between copper ions and catechins to generate reactive oxygen species (ROS) responsible for DNA breakage. Such a copper dependent prooxidant cytotoxic mechanism better explains the anticancer activity and preferential cytotoxicity of dietary phytochemicals against cancer cells.

  5. Cancer Therapy by Catechins Involves Redox Cycling of Copper Ions and Generation of Reactive Oxygen Species

    Directory of Open Access Journals (Sweden)

    Mohd Farhan

    2016-02-01

    Full Text Available Catechins, the dietary phytochemicals present in green tea and other beverages, are considered to be potent inducers of apoptosis and cytotoxicity to cancer cells. While it is believed that the antioxidant properties of catechins and related dietary agents may contribute to lowering the risk of cancer induction by impeding oxidative injury to DNA, these properties cannot account for apoptosis induction and chemotherapeutic observations. Catechin (C, epicatechin (EC, epigallocatechin (EGC and epigallocatechin-3-gallate (EGCG are the four major constituents of green tea. In this article, using human peripheral lymphocytes and comet assay, we show that C, EC, EGC and EGCG cause cellular DNA breakage and can alternatively switch to a prooxidant action in the presence of transition metals such as copper. The cellular DNA breakage was found to be significantly enhanced in the presence of copper ions. Catechins were found to be effective in providing protection against oxidative stress induced by tertbutylhydroperoxide, as measured by oxidative DNA breakage in lymphocytes. The prooxidant action of catechins involved production of hydroxyl radicals through redox recycling of copper ions. We also determined that catechins, particularly EGCG, inhibit proliferation of breast cancer cell line MDA-MB-231 leading to a prooxidant cell death. Since it is well established that tissue, cellular and serum copper levels are considerably elevated in various malignancies, cancer cells would be more subject to redox cycling between copper ions and catechins to generate reactive oxygen species (ROS responsible for DNA breakage. Such a copper dependent prooxidant cytotoxic mechanism better explains the anticancer activity and preferential cytotoxicity of dietary phytochemicals against cancer cells.

  6. Redox-Active Selenium Compounds—From Toxicity and Cell Death to Cancer Treatment

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    Sougat Misra

    2015-05-01

    Full Text Available Selenium is generally known as an antioxidant due to its presence in selenoproteins as selenocysteine, but it is also toxic. The toxic effects of selenium are, however, strictly concentration and chemical species dependent. One class of selenium compounds is a potent inhibitor of cell growth with remarkable tumor specificity. These redox active compounds are pro-oxidative and highly cytotoxic to tumor cells and are promising candidates to be used in chemotherapy against cancer. Herein we elaborate upon the major forms of dietary selenium compounds, their metabolic pathways, and their antioxidant and pro-oxidant potentials with emphasis on cytotoxic mechanisms. Relative cytotoxicity of inorganic selenite and organic selenocystine compounds to different cancer cells are presented as evidence to our perspective. Furthermore, new novel classes of selenium compounds specifically designed to target tumor cells are presented and the potential of selenium in modern oncology is extensively discussed.

  7. High Mobility Group B Proteins, Their Partners, and Other Redox Sensors in Ovarian and Prostate Cancer

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    Aida Barreiro-Alonso

    2016-01-01

    Full Text Available Cancer cells try to avoid the overproduction of reactive oxygen species by metabolic rearrangements. These cells also develop specific strategies to increase ROS resistance and to express the enzymatic activities necessary for ROS detoxification. Oxidative stress produces DNA damage and also induces responses, which could help the cell to restore the initial equilibrium. But if this is not possible, oxidative stress finally activates signals that will lead to cell death. High mobility group B (HMGB proteins have been previously related to the onset and progressions of cancers of different origins. The protein HMGB1 behaves as a redox sensor and its structural changes, which are conditioned by the oxidative environment, are associated with different functions of the protein. This review describes recent advances in the role of human HMGB proteins and other proteins interacting with them, in cancerous processes related to oxidative stress, with special reference to ovarian and prostate cancer. Their participation in the molecular mechanisms of resistance to cisplatin, a drug commonly used in chemotherapy, is also revised.

  8. Thioredoxin-like 2 regulates human cancer cell growth and metastasis via redox homeostasis and NF-kB signaling

    Science.gov (United States)

    Cancer cells have an efficient antioxidant system to counteract their increased generation of ROS. However, whether this ability to survive high levels of ROS has an important role in the growth and metastasis of tumors is not well understood. Here, we demonstrate that the redox protein thioredoxin-...

  9. Hepatic Mitochondrial Redox Potential in Patients with Liver Metastatic Cancers and Circulatory Insufficiency

    Directory of Open Access Journals (Sweden)

    Marek Jarecki

    2003-01-01

    Full Text Available Arterial ketone body ratio (AKBR, which reflects hepatic intramitochodrial redox potential, was measured in 20 patients with Carcinoma hepatis metastaticum and good circulatory condition (group A, and 16 patients with Carcinoma hepatis metastaticum and chronic cardiogenic circulatory insufficiency (group B. Total ketone body concentration (TKB and arterial oxygen tension (PaO2 was simultaneously determined. We have stated that AKBR values in both groups of patients were decreased below the normal level. AKBR values in group B were significantly lower than in group A. At the same time TKB values in both groups were statistically equal and significantly increased above the normal level. The levels of arterial oxygen tension (PaO2 in group A were physiologically high, whereas in group B were significantly decreased. Furthermore arterial oxygen tension of patients in group B correlated with AKBR values significantly. In group A we found statistically significant negative correlation between TKB and AKBR values. Our study indicate that the main mechanism which may explain the decrease of intrahepatic mitochondrial redox potential in patients with liver metastatic cancers and good circulatory condition, is the enhanced beta-oxidation of fatty acids, when the efficiency of NAD+ to NADH reduction in beta-oxidation pathway and tricarboxylic acid cycle is higher than re-oxidation of NADH to NAD+ in the oxidative phosphorylation. In patients with coexisting chronic cardiogenic circulatory insufficiency deprivation of blood oxygen supply initiate the irreversible dysfunction of oxidative phosphorylation.

  10. Plumbagin induces cell death through a copper-redox cycle mechanism in human cancer cells.

    Science.gov (United States)

    Nazeem, S; Azmi, Asfar S; Hanif, Sarmad; Ahmad, Aamir; Mohammad, Ramzi M; Hadi, S M; Kumar, K Sateesh

    2009-09-01

    Plumbagin, a naphthoquinone derived from the medicinal plant Plumbago zeylanica has been shown to exert anticancer and anti-proliferative activities in cells in culture as well as animal tumor models. In our previous paper, we have reported the cytotoxic action of plumbagin in plasmid pBR322 DNA as well as human peripheral blood lymphocytes through a redox mechanism involving copper. Copper has been shown to be capable of mediating the action of several plant-derived compounds through production of reactive oxygen species (ROS). The objective of the present study was to determine whether plumbagin induces apoptosis in human cancer cells through the same mechanism which we proposed earlier. Using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt assay, 3-(4,5-B-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay for cell growth inhibition, histone/DNA ELISA, homogeneous caspase-3/7 assay for apoptosis as well as alkaline comet assay for DNA single-strand breaks detection in this report, we confirm that plumbagin causes effective cell growth inhibition, induces apoptosis and generates single-strand breaks in cancer cells. Incubation of cancer cells with scavengers of ROS and neocuproine inhibited the cytotoxic action of plumbagin proving that generation of ROS and Cu(I) are the critical mediators in plumbagin-induced cell growth inhibition. This study is the first to investigate the copper-mediated anticancer mechanism of plumbagin in human cancer cells and these properties of plumbagin could be further explored for the development of anticancer agents with higher therapeutic indices, especially for skin cancer.

  11. Cold Atmospheric Plasma Treatment Induces Anti-Proliferative Effects in Prostate Cancer Cells by Redox and Apoptotic Signaling Pathways.

    Directory of Open Access Journals (Sweden)

    Martin Weiss

    Full Text Available One of the promising possibilities of the clinical application of cold plasma, so-called cold atmospheric plasma (CAP, is its application on malignant cells and cancer tissue using its anti-neoplastic effects, primarily through the delivery of reactive oxygen and nitrogen species (ROS, RNS. In this study, we investigated the impact of CAP on cellular proliferation and consecutive molecular response mechanisms in established prostate cancer (PC cell lines. PC cells showed a significantly reduced cell growth following CAP treatment as a result of both an immediate increase of intracellular peroxide levels and through the induction of apoptosis indicated by annexin V assay, TUNEL assay, and the evaluation of changes in nuclear morphology. Notably, co-administration of N-acetylcysteine (NAC completely neutralized CAP effects by NAC uptake and rapid conversion to glutathione (GSH. Vitamin C could not counteract the CAP induced effects on cell growth. In summary, relatively short treatments with CAP of 10 seconds were sufficient to induce a significant inhibition of cancer proliferation, as observed for the first time in urogenital cancer. Therefore, it is important to understand the mode of CAP related cell death and clarify and optimize CAP as cancer therapy. Increased levels of peroxides can alter redox-regulated signaling pathways and can lead to growth arrest and apoptosis. We assume that the general intracellular redox homeostasis, especially the levels of cellular GSH and peroxidases such as peroxiredoxins affect the outcome of the CAP treatment.

  12. Cold Atmospheric Plasma Treatment Induces Anti-Proliferative Effects in Prostate Cancer Cells by Redox and Apoptotic Signaling Pathways.

    Science.gov (United States)

    Weiss, Martin; Gümbel, Denis; Hanschmann, Eva-Maria; Mandelkow, Robert; Gelbrich, Nadine; Zimmermann, Uwe; Walther, Reinhard; Ekkernkamp, Axel; Sckell, Axel; Kramer, Axel; Burchardt, Martin; Lillig, Christopher H; Stope, Matthias B

    2015-01-01

    One of the promising possibilities of the clinical application of cold plasma, so-called cold atmospheric plasma (CAP), is its application on malignant cells and cancer tissue using its anti-neoplastic effects, primarily through the delivery of reactive oxygen and nitrogen species (ROS, RNS). In this study, we investigated the impact of CAP on cellular proliferation and consecutive molecular response mechanisms in established prostate cancer (PC) cell lines. PC cells showed a significantly reduced cell growth following CAP treatment as a result of both an immediate increase of intracellular peroxide levels and through the induction of apoptosis indicated by annexin V assay, TUNEL assay, and the evaluation of changes in nuclear morphology. Notably, co-administration of N-acetylcysteine (NAC) completely neutralized CAP effects by NAC uptake and rapid conversion to glutathione (GSH). Vitamin C could not counteract the CAP induced effects on cell growth. In summary, relatively short treatments with CAP of 10 seconds were sufficient to induce a significant inhibition of cancer proliferation, as observed for the first time in urogenital cancer. Therefore, it is important to understand the mode of CAP related cell death and clarify and optimize CAP as cancer therapy. Increased levels of peroxides can alter redox-regulated signaling pathways and can lead to growth arrest and apoptosis. We assume that the general intracellular redox homeostasis, especially the levels of cellular GSH and peroxidases such as peroxiredoxins affect the outcome of the CAP treatment.

  13. IGF-I regulates redox status in breast cancer cells by activating the amino acid transport molecule xC-.

    Science.gov (United States)

    Yang, Yuzhe; Yee, Douglas

    2014-04-15

    Insulin-like growth factors (IGF) stimulate cell growth in part by increasing amino acid uptake. xCT (SLC7A11) encodes the functional subunit of the cell surface transport system xC(-), which mediates cystine uptake, a pivotal step in glutathione synthesis and cellular redox control. In this study, we show that IGF-I regulates cystine uptake and cellular redox status by activating the expression and function of xCT in estrogen receptor-positive (ER(+)) breast cancer cells by a mechanism that relies on the IGF receptor substrate-1 (IRS-1). Breast cancer cell proliferation mediated by IGF-I was suppressed by attenuating xCT expression or blocking xCT activity with the pharmacologic inhibitor sulfasalazine (SASP). Notably, SASP sensitized breast cancer cells to inhibitors of the type I IGF receptor (IGF-IR) in a manner reversed by the reactive oxygen species (ROS) scavenger N-acetyl-L-cysteine. Thus, IGF-I promoted the proliferation of ER(+) breast cancer cells by regulating xC(-) transporter function to protect cancer cells from ROS in an IRS-1-dependent manner. Our findings suggest that inhibiting xC(-) transporter function may synergize with modalities that target the IGF-IR to heighten their therapeutic effects.

  14. The redox state of cytochrome c modulates resistance to methotrexate in human MCF7 breast cancer cells.

    Directory of Open Access Journals (Sweden)

    Susana Barros

    Full Text Available BACKGROUND: Methotrexate is a chemotherapeutic agent used to treat a variety of cancers. However, the occurrence of resistance limits its effectiveness. Cytochrome c in its reduced state is less capable of triggering the apoptotic cascade. Thus, we set up to study the relationship among redox state of cytochrome c, apoptosis and the development of resistance to methotrexate in MCF7 human breast cancer cells. RESULTS: Cell incubation with cytochrome c-reducing agents, such as tetramethylphenylenediamine, ascorbate or reduced glutathione, decreased the mortality and apoptosis triggered by methotrexate. Conversely, depletion of glutathione increased the apoptotic action of methotrexate, showing an involvement of cytochrome c redox state in methotrexate-induced apoptosis. Methotrexate-resistant MCF7 cells showed increased levels of endogenous reduced glutathione and a higher capability to reduce exogenous cytochrome c. Using functional genomics we detected the overexpression of GSTM1 and GSTM4 in methotrexate-resistant MCF7 breast cancer cells, and determined that methotrexate was susceptible of glutathionylation by GSTs. The inhibition of these GSTM isoforms caused an increase in methotrexate cytotoxicity in sensitive and resistant cells. CONCLUSIONS: We conclude that overexpression of specific GSTMs, GSTM1 and GSTM4, together with increased endogenous reduced glutathione levels help to maintain a more reduced state of cytochrome c which, in turn, would decrease apoptosis, thus contributing to methotrexate resistance in human MCF7 breast cancer cells.

  15. Radiation-induced cyclooxygenase 2 up-regulation is dependent on redox status in prostate cancer cells.

    Science.gov (United States)

    Li, Lingyun; Steinauer, Kirsten K; Dirks, Amie J; Husbeck, Bryan; Gibbs, Iris; Knox, Susan J

    2003-12-01

    Cyclooxygenase 2 (COX2) is the inducible isozyme of COX, a key enzyme in arachidonate metabolism and the conversion of arachidonic acid (AA) to prostaglandins (PGs) and other eicosanoids. Previous studies have demonstrated that the COX2 protein is up-regulated in prostate cancer cells after irradiation and that this results in elevated levels of PGE(2). In the present study, we further investigated whether radiation-induced COX2 up-regulation is dependent on the redox status of cells from the prostate cancer cell line PC-3. l-Buthionine sulfoximine (BSO), which inhibits gamma glutamyl cysteine synthetase (gammaGCS), and the antioxidants alpha-lipoic acid and N-acetyl-l-cysteine (NAC) were used to modulate the cellular redox status. BSO decreased the cellular GSH level and increased cellular reactive oxygen species (ROS) in PC-3 cells, whereas alpha-lipoic acid and NAC increased the GSH level and decreased cellular ROS. Both radiation and the oxidant H(2)O(2) had similar effects on COX2 up-regulation and PGE(2) production in PC-3 cells, suggesting that radiation-induced COX2 up-regulation is secondary to the production of ROS. The relative increases in COX2 expression and PGE(2) production induced by radiation and H(2)O(2) were even greater when PC-3 cells were pretreated with BSO. When the cells were pretreated with alpha-lipoic acid or NAC for 24 h, both radiation- and H(2)O(2)-induced COX2 up-regulation and PGE(2) production were markedly inhibited. These results demonstrate that radiation-induced COX2 up-regulation in prostate cancer cells is modulated by the cellular redox status. Radiation-induced increases in ROS levels contribute to the adaptive response of PC-3 cells, resulting in elevated levels of COX2.

  16. Oxidative stress, redox signaling pathways, and autophagy in cachectic muscles of male patients with advanced COPD and lung cancer.

    Science.gov (United States)

    Puig-Vilanova, Ester; Rodriguez, Diego A; Lloreta, Josep; Ausin, Pilar; Pascual-Guardia, Sergio; Broquetas, Joan; Roca, Josep; Gea, Joaquim; Barreiro, Esther

    2015-02-01

    Muscle dysfunction and wasting are predictors of mortality in advanced COPD and malignancies. Redox imbalance and enhanced protein catabolism are underlying mechanisms in COPD. We hypothesized that the expression profile of several biological markers share similarities in patients with cachexia associated with either COPD or lung cancer (LC). In vastus lateralis of cachectic patients with either LC (n=10) or advanced COPD (n=16) and healthy controls (n=10), markers of redox balance, inflammation, proteolysis, autophagy, signaling pathways, mitochondrial function, muscle structure, and sarcomere damage were measured using laboratory and light and electron microscopy techniques. Systemic redox balance and inflammation were also determined. All subjects were clinically evaluated. Compared to controls, in both cachectic groups of patients, a similar expression profile of different biological markers was observed in their muscles: increased levels of muscle protein oxidation and ubiquitination (pmuscle structural abnormalities and sarcomere disruptions were significantly greater (pmuscles of both cachectic patient groups than in controls (pmuscles of cachectic COPD patients (pmuscle wasting and sarcomere disruption in patients with respiratory cachexia: LC and COPD.

  17. The prognostic and predictive power of redox protein expression for anthracycline-based chemotherapy response in locally advanced breast cancer

    Science.gov (United States)

    Woolston, Caroline M; Zhang, Lei; Storr, Sarah J; Al-Attar, Ahmad; Shehata, Mohamed; Ellis, Ian O; Chan, Stephen Y; Martin, Stewart G

    2012-01-01

    Neoadjuvant chemotherapy has become the standard of care for locally advanced primary breast cancer. Anthracycline-based regimens have proven to be one of the most effective treatments in this setting. As certain cytotoxic antineoplastic agents, such as anthracyclines, generate reactive oxygen species as a by-product of their mechanism of action, we examined whether redox protein expression was involved in the response to anthracycline-based chemotherapy and with clinical outcome. Pre-treatment needle core biopsy and post-anthracycline treatment tumour sections were analysed from 98 cases. In all, 32 individuals had a complete clinical response and 17 had a complete pathological response. Immunohistochemical staining was performed for eight redox proteins: thioredoxin, thioredoxin reductase, thioredoxin interacting protein (TxNIP), glutathione S-transferase (GST) π, θ and α, catalase and manganese superoxide dismutase. GST π (P=0.05) and catalase (P=0.045) were associated with pathological complete response in pre-chemotherapy samples. TxNIP (P=0.017) and thioredoxin reductase (P=0.022) were independent prognostic factors for distant metastasis-free survival and TxNIP for overall survival (P=0.014). In oestrogen receptor negative patients that are known to have a poor overall survival, a considerably worse prognosis was seen in cases that exhibited low expression of TxNIP (P=0.000003), stratifying patients into more defined groups. This study indicates the importance of redox regulation in determining breast cancer response to anthracycline-based chemotherapy and provides ways of further stratifying pre-chemotherapy patients to potentially allow more tailored treatments. PMID:22481283

  18. Quantum steering without inequalities

    CERN Document Server

    Chen, Jing-Ling; Wu, Chunfeng; Su, Hong-Yi; Cabello, Adan; Kwek, L C; Oh, C H

    2012-01-01

    We show that, for any two-qubit state, quantum steering can be proven without testing the violation of steering inequalities. We show that steerability is proven if Bob's normalized conditional states after Alice's measurements are pure. This method, which may be seen as the quantum steering analog of Greenberger-Horne-Zeilinger-like tests of Bell nonlocality without Bell inequalities, offers advantages with respect to the existing methods for experimentally testing quantum steering.

  19. Reduced expression of DNA repair and redox signaling protein APE1/Ref-1 impairs human pancreatic cancer cell survival, proliferation, and cell cycle progression.

    Science.gov (United States)

    Jiang, Yanlin; Zhou, Shaoyu; Sandusky, George E; Kelley, Mark R; Fishel, Melissa L

    2010-11-01

    Pancreatic cancer is a deadly disease that is virtually never cured. Understanding the chemoresistance intrinsic to this cancer will aid in developing new regimens. High expression of APE1/Ref-1, a DNA repair and redox signaling protein, is associated with resistance, poor outcome, and angiogenesis; little is known in pancreatic cancer. Immunostaining of adenocarcinoma shows greater APE1/Ref-1 expression than in normal pancreas tissue. A decrease in APE1/Ref-1 protein levels results in pancreatic cancer cell growth inhibition, increased apoptosis, and altered cell cycle progression. Endogenous cell cycle inhibitors increase when APE1/ Ref-1 is reduced, demonstrating its importance to proliferation and growth of pancreatic cancer.

  20. Mechanistic studies of cancer cell mitochondria- and NQO1-mediated redox activation of beta-lapachone, a potentially novel anticancer agent

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jason Z. [Virginia Tech CRC, Blacksburg, VA (United States); Ke, Yuebin [Shenzhen Center for Disease Control and Prevention, Shenzhen 518055 (China); Misra, Hara P. [Virginia Tech CRC, Blacksburg, VA (United States); Trush, Michael A. [Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD (United States); Li, Y. Robert [Campbell University School of Osteopathic Medicine, Buies Creek, NC (United States); Virginia Tech-Wake Forest University SBES, Blacksburg, VA (United States); Department of Biology, University of North Carolina at Greensboro, NC (United States); Zhu, Hong, E-mail: zhu@campbell.edu [Campbell University School of Osteopathic Medicine, Buies Creek, NC (United States); Jia, Zhenquan, E-mail: z_jia@uncg.edu [Department of Biology, University of North Carolina at Greensboro, NC (United States)

    2014-12-15

    Beta-lapachone (beta-Lp) derived from the Lapacho tree is a potentially novel anticancer agent currently under clinical trials. Previous studies suggested that redox activation of beta-Lp catalyzed by NAD(P)H:quinone oxidoreductase 1 (NQO1) accounted for its killing of cancer cells. However, the exact mechanisms of this effect remain largely unknown. Using chemiluminescence and electron paramagnetic resonance (EPR) spin-trapping techniques, this study for the first time demonstrated the real-time formation of ROS in the redox activation of beta-lapachone from cancer cells mediated by mitochondria and NQO1 in melanoma B16–F10 and hepatocellular carcinoma HepG2 cancer cells. ES936, a highly selective NQO1 inhibitor, and rotenone, a selective inhibitor of mitochondrial electron transport chain (METC) complex I were found to significantly block beta-Lp meditated redox activation in B16–F10 cells. In HepG2 cells ES936 inhibited beta-Lp-mediated oxygen radical formation by ∼ 80% while rotenone exerted no significant effect. These results revealed the differential contribution of METC and NQO1 to beta-lapachone-induced ROS formation and cancer cell killing. In melanoma B16–F10 cells that do not express high NQO1 activity, both NOQ1 and METC play a critical role in beta-Lp redox activation. In contrast, in hepatocellular carcinoma HepG2 cells expressing extremely high NQO1 activity, redox activation of beta-Lp is primarily mediated by NQO1 (METC plays a minor role). These findings will contribute to our understanding of how cancer cells are selectively killed by beta-lapachone and increase our ability to devise strategies to enhance the anticancer efficacy of this potentially novel drug while minimizing its possible adverse effects on normal cells. - Highlights: • Both isolated mitochondria and purified NQO1 are able to generate ROS by beta-Lp. • The differential roles of mitochondria and NQO1 in mediating redox activation of beta-Lp • In cancer cells with

  1. Downregulation of the Werner syndrome protein induces a metabolic shift that compromises redox homeostasis and limits proliferation of cancer cells.

    Science.gov (United States)

    Li, Baomin; Iglesias-Pedraz, Juan Manuel; Chen, Leng-Ying; Yin, Fei; Cadenas, Enrique; Reddy, Sita; Comai, Lucio

    2014-04-01

    The Werner syndrome protein (WRN) is a nuclear protein required for cell growth and proliferation. Loss-of-function mutations in the Werner syndrome gene are associated with the premature onset of age-related diseases. How loss of WRN limits cell proliferation and induces replicative senescence is poorly understood. Here, we show that WRN depletion leads to a striking metabolic shift that coordinately weakens the pathways that generate reducing equivalents for detoxification of reactive oxygen species and increases mitochondrial respiration. In cancer cells, this metabolic shift counteracts the Warburg effect, a defining characteristic of many malignant cells, resulting in altered redox balance and accumulation of oxidative DNA damage that inhibits cell proliferation and induces a senescence-like phenotype. Consistent with these findings, supplementation with antioxidant rescues at least in part cell proliferation and decreases senescence in WRN-knockdown cancer cells. These results demonstrate that WRN plays a critical role in cancer cell proliferation by contributing to the Warburg effect and preventing metabolic stress.

  2. Natural dietary anti-cancer chemopreventive compounds: redox-mediated differential signaling mechanisms in cytoprotection of normal cellsversus cytotoxicity in tumor cells

    Institute of Scientific and Technical Information of China (English)

    Sujit NAIR; Wenge LI; Ah-Ng Tony KONG

    2007-01-01

    Many dietary phytochemicals exhibit health-beneficial effects including preven-tion of diseases such as cancer, as well as neurological, cardiovascular, inflam-matory, and metabolic diseases. Evolutionarily, herbivorous and omnivorous animals have been ingesting plants. This interaction between "animal-plant"ecosystems has resulted in an elaborate system of detoxification and defense mechanisms evolved by animals including humans. Mammalian cells, including human cells, respond to these dietary phytochemicals by "non-classical receptor sensing" mechanisms of electrophilic chemical-stress typified by "thiol-modu-lated" cellular signaling events primarily leading to the gene expression of phar-macologically beneficial effects, but sometimes unwanted cytotoxicity also. Our laboratory has been studying two groups of dietary phytochemical cancer-chemopreventive compounds (isothiocyanates and polyphenols), which are effective in chemical-induced, as well as genetically-induced, animal carcinogen-esis models. These compounds typically generate "cellular stress" and modulate gene expression of phase Ⅱ detoxifying/antioxidant enzymes. Electrophiles, reac-tive oxygen species, and reactive nitrogen species are known to act as second messengers in the modulation of many cellular signaling pathways leading to gene expression changes and pharmacological responses. Redox-sensitive tran-scription factors such as nuclear factor-E2-related factor 2 (Nrf2), AP-1, NF-κB, to cite a few examples, sense and transduce changes in the cellular redox status and modulate gene expression responses to oxidative and electrophilic stresses, pre-sumably via sulfhydryl modification of critical cysteine residues found on these proteins and/or other upstream redox-sensitive molecular targets. In the current review, we will explore dietary cancer chemopreventive phytochemicals, discuss the link between oxidative/electrophilic stresses and the redox circuitry, and con-sider different redox

  3. Redox-directed cancer therapeutics: Taurolidine and Piperlongumine as broadly effective antineoplastic agents (review).

    Science.gov (United States)

    Möhler, Hanns; Pfirrmann, Rolf W; Frei, Karl

    2014-10-01

    Targeting the oxygen stress response pathway is considered a promising strategy to exert antineoplastic activity in a broad spectrum of tumor types. Supporting this view, we summarize the mechanism of action of Taurolidine and Piperlongumine, two antineoplastic agents with strikingly broad tumor selectivity. Taurolidine enhances the oxidative stress (ROS) selectively in tumor cells. Its cytotoxicity for various tumor cells in vitro and in vivo, which includes tumor stem cells, is based on the induction of programmed cell death, largely via apoptosis but also necroptosis and autophagy. The redox-directed mechanism of action of Taurolidine is apparent from the finding that reducing agents e.g., N-acetylcysteine or glutathione impair its cytotoxicity, while its effectiveness is enhanced by agents which inhibit the cellular anti‑oxidant capacity. A similar redox-directed antineoplastic action is shown by Piperlongumine, a recently described experimental drug of plant origin. Taurolidine is particularly advantageous in surgical oncology as this taurine-derivative can be applied perioperatively or systemically with good tolerability as shown in initial clinical applications.

  4. Transoral resection of pharyngeal cancer: summary of a National Cancer Institute Head and Neck Cancer Steering Committee Clinical Trials Planning Meeting, November 6-7, 2011, Arlington, Virginia.

    Science.gov (United States)

    Adelstein, David J; Ridge, John A; Brizel, David M; Holsinger, F Christopher; Haughey, Bruce H; O'Sullivan, Brian; Genden, Eric M; Beitler, Jonathan J; Weinstein, Gregory S; Quon, Harry; Chepeha, Douglas B; Ferris, Robert L; Weber, Randal S; Movsas, Benjamin; Waldron, John; Lowe, Val; Ramsey, Scott; Manola, Judith; Yueh, Bevan; Carey, Thomas E; Bekelman, Justin E; Konski, Andre A; Moore, Eric; Forastiere, Arlene; Schuller, David E; Lynn, Jean; Ullmann, Claudio Dansky

    2012-12-01

    Recent advances now permit resection of many pharyngeal tumors through the open mouth, an approach that can greatly reduce the morbidity of surgical exposure. These transoral techniques are being rapidly adopted by the surgical community and hold considerable promise. On November 6-7, 2011, the National Cancer Institute sponsored a Clinical Trials Planning Meeting to address how to further investigate the use of transoral surgery, both in the good prognosis human papillomavirus (HPV)-initiated oropharyngeal cancers, and in those with HPV-unrelated disease. The proceedings of this meeting are summarized.

  5. Signal transducer and activator of transcription 3 and 5 regulate system Xc- and redox balance in human breast cancer cells.

    Science.gov (United States)

    Linher-Melville, Katja; Haftchenary, Sina; Gunning, Patrick; Singh, Gurmit

    2015-07-01

    System Xc- is a cystine/glutamate antiporter that contributes to the maintenance of cellular redox balance. The human xCT (SLC7A11) gene encodes the functional subunit of system Xc-. Transcription factors regulating antioxidant defense mechanisms including system Xc- are of therapeutic interest, especially given that aggressive breast cancer cells exhibit increased system Xc- function. This investigation provides evidence that xCT expression is regulated by STAT3 and/or STAT5A, functionally affecting the antiporter in human breast cancer cells. Computationally analyzing two kilobase pairs of the xCT promoter/5' flanking region identified a distal gamma-activated site (GAS) motif, with truncations significantly increasing luciferase reporter activity. Similar transcriptional increases were obtained after treating cells transiently transfected with the full-length xCT promoter construct with STAT3/5 pharmacological inhibitors. Knock-down of STAT3 or STAT5A with siRNAs produced similar results. However, GAS site mutation significantly reduced xCT transcriptional activity, suggesting that STATs may interact with other transcription factors at more proximal promoter sites. STAT3 and STAT5A were bound to the xCT promoter in MDA-MB-231 cells, and binding was disrupted by pre-treatment with STAT inhibitors. Pharmacologically suppressing STAT3/5 activation significantly increased xCT mRNA and protein levels, as well as cystine uptake, glutamate release, and total levels of intracellular glutathione. Our data suggest that STAT proteins negatively regulate basal xCT expression. Blocking STAT3/5-mediated signaling induces an adaptive, compensatory mechanism to protect breast cancer cells from stress, including reactive oxygen species, by up-regulating xCT expression and the function of system Xc-. We propose that targeting system Xc- together with STAT3/5 inhibitors may heighten therapeutic anti-cancer effects.

  6. Immunotherapy of head and neck cancer: Emerging clinical trials from a National Cancer Institute Head and Neck Cancer Steering Committee Planning Meeting.

    Science.gov (United States)

    Bauman, Julie E; Cohen, Ezra; Ferris, Robert L; Adelstein, David J; Brizel, David M; Ridge, John A; O'Sullivan, Brian; Burtness, Barbara A; Butterfield, Lisa H; Carson, William E; Disis, Mary L; Fox, Bernard A; Gajewski, Thomas F; Gillison, Maura L; Hodge, James W; Le, Quynh-Thu; Raben, David; Strome, Scott E; Lynn, Jean; Malik, Shakun

    2016-12-01

    Recent advances have permitted successful therapeutic targeting of the immune system in head and neck squamous cell carcinoma (HNSCC). These new immunotherapeutic targets and agents are being rapidly adopted by the oncologic community and hold considerable promise. The National Cancer Institute sponsored a Clinical Trials Planning Meeting to address the issue of how to further investigate the use of immunotherapy in patients with HNSCC. The goals of the meeting were to consider phase 2 or 3 trial designs primarily in 3 different patient populations: those with previously untreated, human papillomavirus-initiated oropharyngeal cancers; those with previously untreated, human papillomavirus-negative HNSCC; and those with recurrent/metastatic HNSCC. In addition, a separate committee was formed to develop integrative biomarkers for the clinical trials. The meeting started with an overview of key immune components and principles related to HNSCC, including immunosurveillance and immune escape. Four clinical trial concepts were developed at the meeting integrating different immunotherapies with existing standards of care. These designs were presented for implementation by the head and neck committees of the National Cancer Institute-funded National Clinical Trials Network. This article summarizes the proceedings of this Clinical Trials Planning Meeting, the purpose of which was to facilitate the rigorous development and design of randomized phase 2 and 3 immunotherapeutic trials in patients with HNSCC. Although reviews usually are published immediately after the meeting is held, this report is unique because there are now tangible clinical trial designs that have been funded and put into practice and the studies are being activated to accrual. Cancer 2016. © 2016 American Cancer Society.

  7. Aptamer-Functionalized and Backbone Redox-Responsive Hyperbranched Polymer for Targeted Drug Delivery in Cancer Therapy.

    Science.gov (United States)

    Zhuang, Yuanyuan; Deng, Hongping; Su, Yue; He, Lin; Wang, Ruibin; Tong, Gangsheng; He, Dannong; Zhu, Xinyuan

    2016-06-13

    A novel type of backbone redox-responsive hyperbranched poly(2-((2-(acryloyloxy)ethyl)disulfanyl)ethyl 4-cyano-4-(((propylthio)carbonothioyl)-thio)-pentanoate-co-poly(ethylene glycol) methacrylate) (HPAEG) has been designed and prepared successfully via the combination of reversible addition-fragmentation chain-transfer (RAFT) polymerization and self-condensing vinyl polymerization (SCVP). Owing to the existence of surface vinyl groups, HPAEG could be efficiently functionalized by DNA aptamer AS1411 via Michael addition reaction to obtain an active tumor targeting drug delivery carrier (HPAEG-AS1411). The amphiphilic HPAEG-AS1411 could form nanoparticles by macromolecular self-assembly strategy. Cell Counting Kit-8 (CCK-8) assay illustrated that HPAEG-AS1411 nanoparticles had low cytotoxicity to normal cell line. Flow cytometry and confocal laser scanning microscopy (CLSM) results demonstrated that HPAEG-AS1411 nanoparticles could be internalized into tumor cells via aptamer-mediated endocytosis. Compared with pure HPAEG nanoparticles, HPAEG-AS1411 nanoparticles displayed enhanced tumor cell uptake. When the HPAEG-AS1411 nanoparticles loaded with anticancer drug doxorubicin (DOX) were internalized into tumor cells, the disulfide bonds in the backbone of HPAEG-AS1411 were cleaved by glutathione (GSH) in the cytoplasm, so that DOX was released rapidly. Therefore, DOX-loaded HPAEG-AS1411 nanoparticles exhibited a high tumor cellular proliferation inhibition rate and low cytotoxicity to normal cells. This aptamer-functionalized and backbone redox-responsive hyperbranched polymer provides a promising platform for targeted drug delivery in cancer therapy.

  8. Catalytic therapy of cancer by ascorbic acid involves redox cycling of exogenous/endogenous copper ions and generation of reactive oxygen species.

    Science.gov (United States)

    Hadi, S M; Ullah, M F; Shamim, U; Bhatt, S H; Azmi, A S

    2010-01-01

    Catalytic therapy is a cancer treatment modality based on the generation of reactive oxygen species (ROS) through administration of ascorbate/medicinal herbal extracts and copper. It is known that antioxidants such as ascorbate also exhibit prooxidant activity in the presence of transition metals such as copper. Based on our work and that in the literature, in this review we propose a mechanism for the cytotoxic action of ascorbate against cancer cells. It involves redox cycling of exogenous/endogenous copper ions and the consequent generation of ROS leading to oxidative DNA breakage. Using human peripheral lymphocytes and the Comet assay, we have shown that ascorbic acid is able to cause oxidative breakage in cellular DNA. Such DNA degradation is inhibited by neocuproine (a Cu(I) sequestering agent) and scavengers of ROS indicating that the cellular DNA breakage involves the generation of Cu(I) and formation of ROS. Similar results are also obtained with plant polyphenol antioxidants that are important constituents of medicinal herbal extracts. Copper is an essential component of chromatin and can take part in redox reactions. It is well established that tissue, cellular and serum copper levels are considerably elevated in various malignancies. Therefore, cancer cells may be more subject to electron transfer between copper ions and ascorbate/plant polyphenols to generate ROS. In this review we cite evidence to indicate that in catalytic therapy cytotoxic action against cancer cells involves redox cycling of exogenous/endogenous copper ions.

  9. Experimental temporal quantum steering

    Science.gov (United States)

    Bartkiewicz, Karol; Černoch, Antonín; Lemr, Karel; Miranowicz, Adam; Nori, Franco

    2016-01-01

    Temporal steering is a form of temporal correlation between the initial and final state of a quantum system. It is a temporal analogue of the famous Einstein-Podolsky-Rosen (spatial) steering. We demonstrate, by measuring the photon polarization, that temporal steering allows two parties to verify if they have been interacting with the same particle, even if they have no information about what happened with the particle in between the measurements. This is the first experimental study of temporal steering. We also performed experimental tests, based on the violation of temporal steering inequalities, of the security of two quantum key distribution protocols against individual attacks. Thus, these results can lead to applications for secure quantum communications and quantum engineering. PMID:27901121

  10. Co-delivery of hydrophobic paclitaxel and hydrophilic AURKA specific siRNA by redox-sensitive micelles for effective treatment of breast cancer.

    Science.gov (United States)

    Yin, Tingjie; Wang, Lei; Yin, Lifang; Zhou, Jianping; Huo, Meirong

    2015-08-01

    In this study, a novel redox-sensitive micellar system constructed from a hyaluronic acid-based amphiphilic conjugate (HA-ss-(OA-g-bPEI), HSOP) was successfully developed for tumor-targeted co-delivery of paclitaxel (PTX) and AURKA specific siRNA (si-AURKA). HSOP exhibited excellent loading capacities for both PTX and siRNA with adjustable dosing ratios and desirable redox-sensitivity independently verified by morphological changes of micelles alongside in vitro release of both drugs in different reducing environments. Moreover, flow cytometry and confocal microscopy analysis confirmed that HSOP micelles were capable of simultaneously delivering PTX and siRNA into MDA-MB-231 breast cancer cells via HA-receptor mediated endocytosis followed by rapid transport of cargoes into the cytosol. Successful delivery and transport amplified the synergistic effects between the drugs while leading to substantially greater antitumor efficacy when compared with single drug-loaded micelles and non-sensitive co-loaded micelles. In vivo investigation demonstrated that HSOP micelles could effectively accumulate in tumor sites and possessed the greatest antitumor efficacy over non-sensitive co-delivery control and redox-sensitive single-drug controls. These findings indicated that redox-sensitive HSOP co-delivery system holds great promise for combined drug/gene treatment for targeted cancer therapy.

  11. Redox-active nanoceria depolarize mitochondrial membrane of human colon cancer cells

    Science.gov (United States)

    Jana, Saikat Kumar; Banerjee, Priyanka; Das, Soumen; Seal, Sudipta; Chaudhury, Koel

    2014-06-01

    Nanotherapeutics is emerging as a promising option to the various limitations and side effects associated with conventional chemotherapy. The present study investigates the cytotoxic effect of redox-active cerium oxide nanoparticles (nanoceria) on human colorectal adenocarcinoma-derived cell line (HCT 15). Exposure of these cells to nanoceria for 24 h with concentration ranging between 10 and 100 μM resulted in a significant reduction of cell viability in a dose-dependent manner. Further, at a concentration of 10 µM, nanoceria exhibited time-dependent cytotoxic effect when exposed to the cells for 24, 48, and 72 h. Upon treatment of the cells with nanoceria, reactive oxygen species (ROS) and lipid peroxidation which are indicators of oxidative stress and cytotoxicity increased significantly, in a dose-dependent manner. Nanoceria was also found to depolarize the mitochondrial membrane, thereby collapsing the membrane potential and leading to initiation of apoptosis. Scanning electron microscopic study of nanoceria-treated HCT 15 cells showed morphological changes and loss of filopodia and lamellipodia, indicating arrest of metastatic spread. Summarizing, when cultured HCT 15 cells are exposed to nanoceria, a dose-dependent cytotoxic effect mediated by ROS generation is observed.

  12. A novel class of mitochondria-targeted soft electrophiles modifies mitochondrial proteins and inhibits mitochondrial metabolism in breast cancer cells through redox mechanisms.

    Directory of Open Access Journals (Sweden)

    Praveen K Vayalil

    Full Text Available Despite advances in screening and treatment over the past several years, breast cancer remains a leading cause of cancer-related death among women in the United States. A major goal in breast cancer treatment is to develop safe and clinically useful therapeutic agents that will prevent the recurrence of breast cancers after front-line therapeutics have failed. Ideally, these agents would have relatively low toxicity against normal cells, and will specifically inhibit the growth and proliferation of cancer cells. Our group and others have previously demonstrated that breast cancer cells exhibit increased mitochondrial oxygen consumption compared with non-tumorigenic breast epithelial cells. This suggests that it may be possible to deliver redox active compounds to the mitochondria to selectively inhibit cancer cell metabolism. To demonstrate proof-of-principle, a series of mitochondria-targeted soft electrophiles (MTSEs has been designed which selectively accumulate within the mitochondria of highly energetic breast cancer cells and modify mitochondrial proteins. A prototype MTSE, IBTP, significantly inhibits mitochondrial oxidative phosphorylation, resulting in decreased breast cancer cell proliferation, cell attachment, and migration in vitro. These results suggest MTSEs may represent a novel class of anti-cancer agents that prevent cancer cell growth by modification of specific mitochondrial proteins.

  13. Method of steering a vehicle

    NARCIS (Netherlands)

    Della Penna, M.; Van Passen, M.M.; Abbink, D.A.; Mulder, M.

    2011-01-01

    Vehicle and method of steering such a vehicle, wherein the vehicle has a steering wheel and steerable driving wheels and a transfer system for converting steering wheel actions to a steering angle of the steerable driving wheels, and wherein the transfer system is provided with a predefined stiffnes

  14. Phenolic compounds: the role of redox regulation in neurodegenerative disease and cancer.

    Science.gov (United States)

    Aboul-Enein, Hassan Y; Berczyńsk, Paweł; Kruk, Irena

    2013-03-01

    Much work has been carried out in the last two decades on the role of oxidative stress and antioxidants deficiency in the pathophysiology of civilization diseases. A considerable amount of chemical, biochemical, epidemiological and clinical evidence indicates that (poly)phenolic compounds widely distributed in the plant kingdom, exhibit a wide range effects on biomolecules. The beneficial effects on human health, many of phenolics have been described to their reactive oxygen (ROS) and nitrogen species (RNS) scavenging and antioxidant capacity. The consumption of vegetables, fruits and flavonoid-rich beverages has been reported to prevent against neurodegenerative diseases, cancer, and ageing. This paper reviews the recent data on (1) the role oxidative stress in the pathology of civilization diseases; (2) the protection against oxidative damage due to the toxicity of ROS/RNS; (3) the cellular and molecular interactions of the (poly)phenolic compounds relevant to the prevention of neurodegenerative diseases and cancer, and (4) the methods for assessing antioxidant capacity.

  15. The Oncogenic Properties Of The Redox Inflammatory Protein Inducible Nitric Oxide Synthase In ER(- Breast Cancer

    Directory of Open Access Journals (Sweden)

    David A. Wink

    2015-08-01

    Full Text Available Inflammation generates reactive chemical species that induce conditions of oxidative nitrosative stress as emerged as factor in poor outcome of many cancers. Our recent findings show that in the inflammatory protein inducible nitric oxide synthase (iNOS is a strong predictor of poor outcome in ER(- patients (Glynn et al. JCI 2010. Furthermore 46 genes, of which 23 were associated with basal like breast cancer, were elevated when iNOS high. In vitro studies using ER(- cell lines showed that fluxes of nitric oxide (NO delivered by NO donors surprising mimic this relationship in the patient cohort. Using this model, we show that NO at different specific concentrations stimulate pro-oncogenic mechanisms such as AKT, ERK, NFkB, AP-1, and HIF-1α that lead to increase of metastatic and cancer stem cells proteins. In addition, we show that tumor suppressor gene BRCA1 and PP2A are inhibited by these NO levels. Similarly other studies show that these concentrations of NO increase immunosuppressive proteins TGF-β and IL-10 in leukocytes to decrease efficacy of some anticancer therapies further contributing to pro-tumorigenic environment. Using this model we have identified several new compounds that have efficacy in xenographic models. These finding have provided a model that shows how NO can affect numerous mechanism that leads to a more aggressive phenotype.

  16. Hyaluronic acid functional amphipathic and redox-responsive polymer particles for the co-delivery of doxorubicin and cyclopamine to eradicate breast cancer cells and cancer stem cells

    Science.gov (United States)

    Hu, Kelei; Zhou, Huige; Liu, Ying; Liu, Zhu; Liu, Jing; Tang, Jinglong; Li, Jiayang; Zhang, Jiakun; Sheng, Wang; Zhao, Yuliang; Wu, Yan; Chen, Chunying

    2015-04-01

    Cancer stem cells (CSCs) have the ability to transform into bulk cancer cells, to promote tumor growth and establish tumor metastasis. To effectively inhibit tumor growth and prevent metastasis, treatments with conventional chemotherapy drugs should be combined with CSC targeted drugs. In this study, we describe the synthesis and characterization of a new amphiphilic polymer, hyaluronic acid-cystamine-polylactic-co-glycolic acid (HA-SS-PLGA), composed of a hydrophobic PLGA head and a hydrophilic HA segment linked by a bioreducible disulfide bond. With a double emulsion method, a nano delivery system was constructed to deliver doxorubicin (DOX) and cyclopamine (CYC, a primary inhibitor of the hedgehog signaling pathway of CSCs) to both a CD44-overexpressing breast CSC subpopulation and bulk breast cancer cells and allow an on-demand release. The resulting drug-loaded NPs exhibited a redox-responsive drug release profile. Dual drug-loaded particles potently diminished the number and size of tumorspheres and HA showed a targeting effect towards breast CSCs. In vivo combination therapy further demonstrated a remarkable synergistic anti-tumor effect and prolonged survival compared to mono-therapy using the orthotopic mammary fat pad tumor growth model. The co-delivery of drug and the CSC specific inhibitor towards targeted cancer chemotherapeutics provides an insight into anticancer strategy with facile control and high efficacy.Cancer stem cells (CSCs) have the ability to transform into bulk cancer cells, to promote tumor growth and establish tumor metastasis. To effectively inhibit tumor growth and prevent metastasis, treatments with conventional chemotherapy drugs should be combined with CSC targeted drugs. In this study, we describe the synthesis and characterization of a new amphiphilic polymer, hyaluronic acid-cystamine-polylactic-co-glycolic acid (HA-SS-PLGA), composed of a hydrophobic PLGA head and a hydrophilic HA segment linked by a bioreducible disulfide bond

  17. Steering Performance, Tactical Vehicles

    Science.gov (United States)

    2015-07-29

    installation introduces minimum friction to the steering system. 2.4.2 Auto -Pilot Device. A steering robot is used to analyze vehicle stability and...system. **The use of brand names does not constitute endorsement by the Army or any other agency of the Federal Government, nor does it imply that it...Size. (3) Construction (radial, bias ply, number of plies). (4) Brand and model. (5) Load range, maximum load carrying capacity. (6

  18. Design of Pneumatic Collapsible Steering

    Directory of Open Access Journals (Sweden)

    Anish Nair

    2013-08-01

    Full Text Available The steering wheel is the important cause of fatal injury for drivers in frontal collision. When frontal collision occurs, due to the kinetic energy of driver or occupant body, it moves forward against steering wheel and wind shield. Actually in a frontal collision forces will be first transmitted through driver’s feet which act as fulcrum so the body will rotate about it. For the taller driver steering works as fulcrum. Driver head & chest hit the steering or windshield which may cause severe injury or death. Considering the injury potential of steering wheel we are presenting a new idea Pneumatic Collapsible Steering Column (PCS.

  19. CCCT - Patient Advocate Steering Committee

    Science.gov (United States)

    The Patient Advocate Steering Committee (PASC) works to ensure advocates involved with the Scientific Steering Committees (SSCs) are completely integrated in the development, implementation, and monitoring of clinical trials within those groups.

  20. 49 CFR 570.60 - Steering system.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Steering system. 570.60 Section 570.60... 10,000 Pounds § 570.60 Steering system. (a) System play. Lash or free play in the steering system... excessive lash or free play in the steering system. Table 2. Steering Wheel Free Play Values Steering...

  1. Steering Your Mysterious Mind

    DEFF Research Database (Denmark)

    Prasad, Ramjee

    Steering the Mysterious Mind, describes a unique, novel concept for a way to gain control of your mind. The five basic elements of human life, that is; Creativity, Content­ment, Confidence, Calmness, and Concentration (C5) have been introduced in my previous book Unlock Your Personalization...

  2. Loophole-free quantum steering

    CERN Document Server

    Wittmann, Bernhard; Steinlechner, Fabian; Langford, Nathan K; Brunner, Nicolas; Wiseman, Howard; Ursin, Rupert; Zeilinger, Anton

    2011-01-01

    Tests of the predictions of quantum mechanics for entangled systems have provided increasing evidence against local realistic theories 1-6. However, there still remains the crucial challenge of simultaneously closing all major loopholes - the locality, freedom-of-choice, and detection loopholes - in a single experiment. An important sub-class of local realistic theories can be tested with the concept of "steering". The term steering was introduced by Schr\\"odinger in 1935 for the fact that entanglement would seem to allow an experimenter to remotely steer the state of a distant system 7. Einstein called this "spooky action at a distance" 8. Steering has recently been rigorously formulated as a quantum information task opening it up to new experimental tests 9-11. Here, we present the first loophole-free demonstration of steering by violating three-setting quadratic steering inequality, tested with polarization entangled photons shared between two distant laboratories. Our experiment demonstrates this effect w...

  3. Computational Steering with Reduced Complexity

    OpenAIRE

    Butnaru, Daniel

    2014-01-01

    Computational Steering increases the understanding of relationships between the output of a simulation and its parametrized input, such as boundary conditions, physical parameters, or domain geometry. Steering relies on a running simulation which delivers results to a visualization system. However, many simulation codes cannot deliver the required interactive results. For the first time, this work investigates the use of surrogate models to augment computational steering approaches. Based...

  4. Correlating two-photon excited fluorescence imaging of breast cancer cellular redox state with seahorse flux analysis of normalized cellular oxygen consumption

    Science.gov (United States)

    Hou, Jue; Wright, Heather J.; Chan, Nicole; Tran, Richard; Razorenova, Olga V.; Potma, Eric O.; Tromberg, Bruce J.

    2016-06-01

    Two-photon excited fluorescence (TPEF) imaging of the cellular cofactors nicotinamide adenine dinucleotide and oxidized flavin adenine dinucleotide is widely used to measure cellular metabolism, both in normal and pathological cells and tissues. When dual-wavelength excitation is used, ratiometric TPEF imaging of the intrinsic cofactor fluorescence provides a metabolic index of cells-the "optical redox ratio" (ORR). With increased interest in understanding and controlling cellular metabolism in cancer, there is a need to evaluate the performance of ORR in malignant cells. We compare TPEF metabolic imaging with seahorse flux analysis of cellular oxygen consumption in two different breast cancer cell lines (MCF-7 and MDA-MB-231). We monitor metabolic index in living cells under both normal culture conditions and, for MCF-7, in response to cell respiration inhibitors and uncouplers. We observe a significant correlation between the TPEF-derived ORR and the flux analyzer measurements (R=0.7901, p<0.001). Our results confirm that the ORR is a valid dynamic index of cell metabolism under a range of oxygen consumption conditions relevant for cancer imaging.

  5. Research on the Variable Steering Ratio of Four-Wheel-Steering Vehicle

    Institute of Scientific and Technical Information of China (English)

    林程; 陈思忠; 任良成

    2004-01-01

    The steering characteristic of a four-wheel-steering vehicle is numerically simulated for in-depth research of the handling stability of four-wheel steering. The research results show that the deteriorating tendency of the steering stability due to the increase of the vehicle speed is improved obviously in the case of four-wheel steering. The approach of variable steering ratio is discussed. The use of the variable steering ratio can not only raise the steering stability of vechicles at high vehicle speed, but also reduce the dicomfort and steering burden of drivers; and hence is helpful for the subjective evaluation of four-wheel steering vehicles.

  6. Quantum coherence of steered states

    Science.gov (United States)

    Hu, Xueyuan; Milne, Antony; Zhang, Boyang; Fan, Heng

    2016-01-01

    Lying at the heart of quantum mechanics, coherence has recently been studied as a key resource in quantum information theory. Quantum steering, a fundamental notion originally considered by Schödinger, has also recently received much attention. When Alice and Bob share a correlated quantum system, Alice can perform a local measurement to ‘steer’ Bob’s reduced state. We introduce the maximal steered coherence as a measure describing the extent to which steering can remotely create coherence; more precisely, we find the maximal coherence of Bob’s steered state in the eigenbasis of his original reduced state, where maximization is performed over all positive-operator valued measurements for Alice. We prove that maximal steered coherence vanishes for quantum-classical states whilst reaching a maximum for pure entangled states with full Schmidt rank. Although invariant under local unitary operations, maximal steered coherence may be increased when Bob performs a channel. For a two-qubit state we find that Bob’s channel can increase maximal steered coherence if and only if it is neither unital nor semi-classical, which coincides with the condition for increasing discord. Our results show that the power of steering for coherence generation, though related to discord, is distinct from existing measures of quantum correlation.

  7. A novel label-free electrochemical miRNA biosensor using methylene blue as redox indicator: application to breast cancer biomarker miRNA-21.

    Science.gov (United States)

    Rafiee-Pour, Hossain-Ali; Behpour, Mohsen; Keshavarz, Mahin

    2016-03-15

    Small noncoding microRNAs (miRNAs) have emerged as ideal noninvasive biomarkers for early-phase cancer detection. In this report, a label-free and simple electrochemical miRNA biosensor is developed based on employing methylene blue (MB) as a redox indicator. The successfully immobilization of the single strand DNA (ss-DNA) probe and hybridization with the target miRNA sequence were confirmed by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) methods. Differential pulse voltammetry (DPV) technique was used to record the oxidation peak current of MB under optimal condition and an increase in the peak current was observed after hybridization. By employing this strategy, miRNA can detect in a range from 0.1 to 500.0 pM with a relatively low detection limit of 84.3 fM. The electrochemical response of MB on ss-DNA and duplex of miRNA/DNA was characterized by CV and chronocoulometry method. The linear relation between the redox peak currents (Ip) and scan rate (ν) indicates that the electron transfer (ET) between MB and the electrode surface was mediated by the miRNA/DNA π-stacked duplex. The value of surface coverage (Γ) was calculated that indicated increase amount of MB on the surface of modified electrode after hybridization event and revealed the adsorption of MB at modified electrode is monolayer. Also, the electron transfer rate constants (ks) of MB were estimated. The results of kinetic analysis were confirmed by chronocoulometry method. The discrimination ability of miRNA biosensor even against a noncomplementary target was also studied. Consequently, this strategy will be valuable for sensitive, selective and label-free detection of miRNA.

  8. Mesenchymal phenotype predisposes lung cancer cells to impaired proliferation and redox stress in response to glutaminase inhibition.

    Directory of Open Access Journals (Sweden)

    Danielle B Ulanet

    Full Text Available Recent work has highlighted glutaminase (GLS as a key player in cancer cell metabolism, providing glutamine-derived carbon and nitrogen to pathways that support proliferation. There is significant interest in targeting GLS for cancer therapy, although the gene is not known to be mutated or amplified in tumors. As a result, identification of tractable markers that predict GLS dependence is needed for translation of GLS inhibitors to the clinic. Herein we validate a small molecule inhibitor of GLS and show that non-small cell lung cancer cells marked by low E-cadherin and high vimentin expression, hallmarks of a mesenchymal phenotype, are particularly sensitive to inhibition of the enzyme. Furthermore, lung cancer cells induced to undergo epithelial to mesenchymal transition (EMT acquire sensitivity to the GLS inhibitor. Metabolic studies suggest that the mesenchymal cells have a reduced capacity for oxidative phosphorylation and increased susceptibility to oxidative stress, rendering them unable to cope with the perturbations induced by GLS inhibition. These findings elucidate selective metabolic dependencies of mesenchymal lung cancer cells and suggest novel pathways as potential targets in this aggressive cancer type.

  9. Frequency Steered Acoustic Transducer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase I project is to develop, fabricate, and characterize a novel frequency steered acoustic transducer (FSAT) for the...

  10. STEER Coastal Use Mapping Project

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Coastal Use Mapping Project is designed to collect critical information on human activities in and near the St. Thomas East End Reserves (STEER). The project...

  11. Frequency Steered Acoustic Transducer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase II project is to fabricate, characterize, and verify performance of a new type of frequency steered acoustic transducer...

  12. Responder fast steering mirror

    Science.gov (United States)

    Bullard, Andrew; Shawki, Islam

    2013-10-01

    Raytheon Space and Airborne Systems (SAS) has designed, built and tested a 3.3-inch diameter fast steering mirror (FSM) for space application. This 2-axis FSM operates over a large angle (over 10 degree range), has a very high servo bandwidth (over 3.3 Khz closed loop bandwidth), has nanoradian-class noise, and is designed to support microradian class line of sight accuracy. The FSM maintains excellent performance over large temperature ranges (which includes wave front error) and has very high reliability with the help of fully redundant angle sensors and actuator circuits. The FSM is capable of achieving all its design requirements while also being reaction-compensated. The reaction compensation is achieved passively and does not need a separate control loop. The FSM has undergone various environmental testing which include exported forces and torques and thermal vacuum testing that support the FSM design claims. This paper presents the mechanical design and test results of the mechanism which satisfies the rigorous vacuum and space application requirements.

  13. Simulating hypoxia-induced acidic environment in cancer cells facilitates mobilization and redox-cycling of genomic copper by daidzein leading to pro-oxidant cell death: implications for the sensitization of resistant hypoxic cancer cells to therapeutic challenges.

    Science.gov (United States)

    Ullah, Mohammad F; Ahmad, Aamir; Bhat, Showket H; Khan, Husain Y; Zubair, Haseeb; Sarkar, Fazlul H; Hadi, Sheikh M

    2016-04-01

    This study was conducted to investigate the mechanism of action involved in the anti-cancer activity of daidzein and identification of cancer specific micro-environment as therapeutic target of this secondary metabolite derived from soy. Our data indicated that daidzein induces cellular DNA breakage, anti-proliferative effects and apoptosis in a concentration-dependent manner. We demonstrated that such a daidzein-induced anti-cancer action involves a copper-dependant pathway in which endogenous copper is mobilized by daidzein and redox-cycled to generate reactive oxygen species which act as an upstream signal leading to pro-oxidant cell death. Further in the context of hypoxia being a resistant factor against standard therapies and that an effect secondary to hypoxia is the intracellular acidification, we show that the anticancer activity of daidzein is modulated positively in acidic pH but copper-specific chelator is still able to inhibit daidzein activity. Moreover, an experimental setup of hypoxia mimic (cobalt chloride) revealed an enhanced sensitivity of cancer cells to the cytotoxic effects of daidzein which was neutralized in the presence of neocuproine. The findings support a paradigm shift from the conventional antioxidant property of dietary isoflavones to molecules capable of initiating a pro-oxidant signaling mediated by reactive oxygen species. Further, the clinical relevance of such an action mechanism in cancer chemoprevention is also proposed. This study identified endogenous copper as a molecular target and acidic pH as a modulating factor for the therapeutic activity of daidzein against cancer. The evidence presented highlights the potential of dietary agents as adjuvants to standard therapeutic regimens.

  14. Stomach Cancer: Interconnection between the Redox State, Activity of MMP-2, MMP-9 and Stage of Tumor Growth.

    Science.gov (United States)

    Burlaka, Anatoly P; Ganusevich, Irina I; Gafurov, Marat R; Lukin, Sergey M; Sidorik, Evgeny P

    2016-04-01

    High levels of reactive oxygen (ROS) and nitrogen (RNS) species can lead to the destruction of extracellular matrix facilitating tumor progression. ROS can activate matrix metalloproteinases (MMP), damage DNA and RNA. Therefore, the levels of MMP, ROS and RNS can serve as additional prognostic markers and for the estimation of the effectiveness of tumor therapy. Concerning gastric cancer, the prognostic role of MMP, its connection with the cancer staging remains controversial and correlations between the activity of MMP with the ROS and RNS levels are insufficiently confirmed. Superoxide generation rates, nitric oxide (NO) levels, concentrations of active forms of matrix metalloproteinases MMP-2 and MMP-9 in tumor and adjacent tissues of patients with stomach cancer at different disease stages were measured by electron spin resonance (ESR) including spin-trapping and polyacrylamide gel zymography. It is shown that the activity of MMP-2 and MMP-9 in tumor tissue correlate with the superoxide radicals generation rate and NO levels (r = 0.48÷0.67, p < 0.05). The activity of MMP-2 and MMP-9 in tumor tissues and superoxide radical generation rates correlate positively with the stage of regional dissemination (r = 0.45 and 0.37, correspondingly, p < 0.05), but MMP-2 and MMP-9 activity inversely depends on distant metastatic degree of stomach cancer (r = 0.58; p < 0.05). Additionally, the feasibility of ESR to locally determine oxidative stress is demonstrated.

  15. Phospho-sulindac (OXT-922) inhibits the growth of human colon cancer cell lines: a redox/polyamine-dependent effect.

    Science.gov (United States)

    Huang, Liqun; Zhu, Caihua; Sun, Yu; Xie, Gang; Mackenzie, Gerardo G; Qiao, George; Komninou, Despina; Rigas, Basil

    2010-11-01

    Non-steroidal anti-inflammatory drugs such as sulindac are promising chemoprevention agents against colon cancer, but their weak potency and side effects limit their use for both chemoprevention and chemotherapy. Here, we evaluated the effect of a new sulindac derivative, phospho-sulindac or OXT-922, on the growth of human cancer cell lines and its mechanism of action. OXT-922 inhibited the growth of human cancer cell lines originating from colon, pancreas and breast ~11- to 30-fold more potently than sulindac. This effect was mediated by a strong cytokinetic effect. Compared with control, OXT-922 inhibited cell proliferation by up to 67%, induced apoptosis 4.1-fold over control and blocked the G(1) to S cell cycle phase transition. OXT-922 suppressed the levels of cell cycle regulating proteins, including cyclins D(1) and D(3) and Cyclin-dependent kinases (CDK) 4 and 6. The levels of intracellular reactive oxygen species (ROS), especially those of mitochondrial O₂ⁱ⁻, were markedly elevated (5.5-fold) in response to OXT-922. ROS collapsed the mitochondrial membrane potential and triggered apoptosis, which was largely abrogated by antioxidants. OXT-922 suppressed nuclear factor-kappaB activation and downregulated thioredoxin-1 expression. It also suppressed the production of prostaglandin E(2) and decreased cyclooxygenase-1 expression. Similar to sulindac, OXT-922 enhanced spermidine/spermine N(1)-acetyltransferase activity, reduced the cellular polyamine content and synergized with difluoromethylornithine to inhibit cancer cell proliferation and induce apoptosis. Our results suggest that OXT-922 possesses promising anticancer properties and deserves further evaluation.

  16. Mitochondria and redox homoeostasis as chemotherapeutic targets of Araucaria angustifolia (Bert.) O. Kuntze in human larynx HEp-2 cancer cells.

    Science.gov (United States)

    Branco, Cátia dos Santos; de Lima, Émilin Dreher; Rodrigues, Tiago Selau; Scheffel, Thamiris Becker; Scola, Gustavo; Laurino, Claudia Cilene Fernandes Correia; Moura, Sidnei; Salvador, Mirian

    2015-04-25

    Natural products are among one of the most promising fields in finding new molecular targets in cancer therapy. Laryngeal carcinoma is one of the most common cancers affecting the head and neck regions, and is associated with high morbidity rate if left untreated. The aim of this study was to examine the antiproliferative effect of Araucaria angustifolia on laryngeal carcinoma HEp-2 cells. The results showed that A. angustifolia extract (AAE) induced a significant cytotoxicity in HEp-2 cells compared to the non-tumor human epithelial (HEK-293) cells, indicating a selective activity of AAE for the cancer cells. A. angustifolia extract was able to increase oxidative damage to lipids and proteins, and the production of nitric oxide, along with the depletion of enzymatic antioxidant defenses (superoxide dismutase and catalase) in the tumor cell line. Moreover, AAE was able to induce DNA damage, nuclear fragmentation and chromatin condensation. A significant increase in the Apoptosis Inducing Factor (AIF), Bax, poly-(ADP-ribose) polymerase (PARP) and caspase-3 cleavage expression were also found. These effects could be related to the ability of AAE to increase the production of reactive oxygen species through inhibition of the mitochondrial electron transport chain complex I activity and ATP production by the tumor cells. The phytochemical analysis of A. angustifolia, performed using High Resolution Mass Spectrometry (HRMS) in MS and MS/MS mode, showed the presence of dodecanoic and hexadecanoic acids, and phenolic compounds, which may be associated with the chemotherapeutic effect observed in this study.

  17. Fermilab Steering Group Report

    Energy Technology Data Exchange (ETDEWEB)

    Steering Group, Fermilab; /Fermilab

    2007-12-01

    The Fermilab Steering Group has developed a plan to keep U.S. accelerator-based particle physics on the pathway to discovery, both at the Terascale with the LHC and the ILC and in the domain of neutrinos and precision physics with a high-intensity accelerator. The plan puts discovering Terascale physics with the LHC and the ILC as Fermilab's highest priority. While supporting ILC development, the plan creates opportunities for exciting science at the intensity frontier. If the ILC remains near the Global Design Effort's technically driven timeline, Fermilab would continue neutrino science with the NOvA experiment, using the NuMI (Neutrinos at the Main Injector) proton plan, scheduled to begin operating in 2011. If ILC construction must wait somewhat longer, Fermilab's plan proposes SNuMI, an upgrade of NuMI to create a more powerful neutrino beam. If the ILC start is postponed significantly, a central feature of the proposed Fermilab plan calls for building an intense proton facility, Project X, consisting of a linear accelerator with the currently planned characteristics of the ILC combined with Fermilab's existing Recycler Ring and the Main Injector accelerator. The major component of Project X is the linac. Cryomodules, radio-frequency distribution, cryogenics and instrumentation for the linac are the same as or similar to those used in the ILC at a scale of about one percent of a full ILC linac. Project X's intense proton beams would open a path to discovery in neutrino science and in precision physics with charged leptons and quarks. World-leading experiments would allow physicists to address key questions of the Quantum Universe: How did the universe come to be? Are there undiscovered principles of nature: new symmetries, new physical laws? Do all the particles and forces become one? What happened to the antimatter? Building Project X's ILC-like linac would offer substantial support for ILC development by accelerating the

  18. Fermilab Steering Group Report

    Energy Technology Data Exchange (ETDEWEB)

    Beier, Eugene; /Pennsylvania U.; Butler, Joel; /Fermilab; Dawson, Sally; /Brookhaven; Edwards, Helen; /Fermilab; Himel, Thomas; /SLAC; Holmes, Stephen; /Fermilab; Kim, Young-Kee; /Fermilab /Chicago U.; Lankford, Andrew; /UC, Irvine; McGinnis, David; /Fermilab; Nagaitsev, Sergei; /Fermilab; Raubenheimer, Tor; /SLAC /Fermilab

    2007-01-01

    The Fermilab Steering Group has developed a plan to keep U.S. accelerator-based particle physics on the pathway to discovery, both at the Terascale with the LHC and the ILC and in the domain of neutrinos and precision physics with a high-intensity accelerator. The plan puts discovering Terascale physics with the LHC and the ILC as Fermilab's highest priority. While supporting ILC development, the plan creates opportunities for exciting science at the intensity frontier. If the ILC remains near the Global Design Effort's technically driven timeline, Fermilab would continue neutrino science with the NOVA experiment, using the NuMI (Neutrinos at the Main Injector) proton plan, scheduled to begin operating in 2011. If ILC construction must wait somewhat longer, Fermilab's plan proposes SNuMI, an upgrade of NuMI to create a more powerful neutrino beam. If the ILC start is postponed significantly, a central feature of the proposed Fermilab plan calls for building an intense proton facility, Project X, consisting of a linear accelerator with the currently planned characteristics of the ILC combined with Fermilab's existing Recycler Ring and the Main Injector accelerator. The major component of Project X is the linac. Cryomodules, radio-frequency distribution, cryogenics and instrumentation for the linac are the same as or similar to those used in the ILC at a scale of about one percent of a full ILC linac. Project X's intense proton beams would open a path to discovery in neutrino science and in precision physics with charged leptons and quarks. World-leading experiments would allow physicists to address key questions of the Quantum Universe: How did the universe come to be? Are there undiscovered principles of nature: new symmetries, new physical laws? Do all the particles and forces become one? What happened to the antimatter? Building Project X's ILC-like linac would offer substantial support for ILC development by accelerating the

  19. Bulling among yearling feedlot steers.

    Science.gov (United States)

    Pierson, R E; Jensen, R; Braddy, P M; Horton, D P; Christie, R M

    1976-09-01

    In a survey to determine the cause of illness and deaths among yearling feedlot cattle, bulling was found to be one of the major problems. During the years 1971-1974, 54,913 (2.88%) steers became bullers and represented an annual loss of around +325,000. Some of the causes of bulling were found to be hormones, either as implants or in the feed. In 1974, from 1,988 necropsies, it was determined that 83 steers died from riding injuries.

  20. Joint Measurability and Temporal Steering

    OpenAIRE

    Karthik, H. S.; Tej, J Prabhu; Devi, A. R. Usha; Rajagopal, A. K.

    2014-01-01

    Quintino et. al. (Phys. Rev. Lett. 113, 160402 (2014)) and Uola et. al. (Phys. Rev. Lett. 113, 160403 (2014)) have recently established an intrinsic relation between non-joint measurability and Einstein-Podolsky- Rosen steering. They showed that a set of measurements is incompatible (i.e., not jointly measurable) if and only if it can be used for the demonstration of steering. In this paper, we prove the temporal analog of this result viz., a set of measurements are incompatible if and only i...

  1. A survey of computational steering environments

    NARCIS (Netherlands)

    Mulder, J.D.; Wijk, J.J. van; Liere, R. van

    1998-01-01

    Computational steering is a powerful concept that allows scientists to interactively control a computational process during its execution. In this paper, a survey of computational steering environments for the on-line steering of ongoing scientific and engineering simulations is presented. These env

  2. Plant redox proteomics

    DEFF Research Database (Denmark)

    Navrot, Nicolas; Finnie, Christine; Svensson, Birte

    2011-01-01

    In common with other aerobic organisms, plants are exposed to reactive oxygen species resulting in formation of post-translational modifications related to protein oxidoreduction (redox PTMs) that may inflict oxidative protein damage. Accumulating evidence also underscores the importance of redox...... PTMs in regulating enzymatic activities and controlling biological processes in plants. Notably, proteins controlling the cellular redox state, e.g. thioredoxin and glutaredoxin, appear to play dual roles to maintain oxidative stress resistance and regulate signal transduction pathways via redox PTMs....... To get a comprehensive overview of these types of redox-regulated pathways there is therefore an emerging interest to monitor changes in redox PTMs on a proteome scale. Compared to some other PTMs, e.g. protein phosphorylation, redox PTMs have received less attention in plant proteome analysis, possibly...

  3. Inhibition of angiogenesis- and inflammation-inducing factors in human colon cancer cells in vitro and in ovo by free and nanoparticle-encapsulated redox dye, DCPIP

    Directory of Open Access Journals (Sweden)

    Anant Shrikant

    2010-07-01

    Full Text Available Abstract Background The redox dye, DCPIP, has recently shown to exhibit anti-melanoma activity in vitro and in vivo. On the other hand, there is increasing evidence that synthetic nanoparticles can serve as highly efficient carriers of drugs and vaccines for treatment of various diseases. These nanoparticles have shown to serve as potent tools that can increase the bioavailability of the drug/vaccine by facilitating absorption or conferring sustained and improved release. Here, we describe results on the effects of free- and nanoparticle-enclosed DCPIP as anti-angiogenesis and anti-inflammation agents in a human colon cancer HCT116 cell line in vitro, and in induced angiogenesis in ovo. Results The studies described in this report indicate that (a DCPIP inhibits proliferation of HCT116 cells in vitro; (b DCPIP can selectively downregulate expression of the pro-angiogenesis growth factor, VEGF; (c DCPIP inhibits activation of the transcriptional nuclear factor, NF-κB; (d DCPIP can attenuate or completely inhibit VEGF-induced angiogenesis in the chick chorioallantoic membrane; (e DCPIP at concentrations higher than 6 μg/ml induces apoptosis in HCT116 cells as confirmed by detection of caspase-3 and PARP degradation; and (f DCPIP encapsulated in nanoparticles is equally or more effective than free DCPIP in exhibiting the aforementioned properties (a-e in addition to reducing the expression of COX-2, and pro-inflammatory proteins IL-6 and IL-8. Conclusions We propose that, DCPIP may serve as a potent tool to prevent or disrupt the processes of cell proliferation, tissue angiogenesis and inflammation by directly or indirectly targeting expression of specific cellular factors. We also propose that the activities of DCPIP may be long-lasting and/or enhanced if it is delivered enclosed in specific nanoparticles.

  4. Objective Evaluation Method of Steering Comfort Based on Movement Quality Evaluation of Driver Steering Maneuver

    Institute of Scientific and Technical Information of China (English)

    YANG Yiyong; LIU Yahui; WANG Man; JI Run; JI Xuewu

    2014-01-01

    The existing research of steering comfort mainly focuses on the subjective evaluation, aiming at designing and optimizing the steering system. In the development of steering system, especially the evaluation of steering comfort, the objective evaluation methods considered the kinematic characteristics of driver steering maneuver are not proposed, which means that the objective evaluation of steering cannot be conducted with the evaluation of kinematic characteristics of driver in steering maneuver. In order to propose the objective evaluation methods of steering comfort, the evaluation of steering movement quality of driver is developed on the basis of the study of the kinematic characteristics of steering maneuver. First, the steering motion trajectories of the driver in both comfortable and certain extreme uncomfortable operation conditions are detected using the Vicon motion capture system. The operation conditions are under the restrictions of the vertical height and horizontal distance between steering wheel center and the H-point of driver, and the steering resisting torque else. Next, the movement quality evaluation of driver steering maneuver is assessed using twelve kinds of evaluation indices based on the kinematic analyses of the steering motion trajectories to propose an objective evaluation method. Finally, an integrated discomfort index of steering maneuver is proposed on the basis of the regression analysis of subjective evaluation rating and the movement quality evaluation indices, including the Jerk, Discomfort and Joint Torque indices. The test results show that the proposed integrated discomfort index gives a good fitting with the subjective evaluation of discomfort, which means it can be used to evaluate or predict the discomfort level of steering maneuver. This paper proposes an objective evaluation method of steering comfort based on the movement quality evaluation of driver steering maneuver.

  5. 46 CFR 182.610 - Main steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Main steering gear. 182.610 Section 182.610 Shipping...) MACHINERY INSTALLATION Steering Systems § 182.610 Main steering gear. (a) A vessel must be provided with a main steering gear that is: (1) Of adequate strength and capable of steering the vessel at all...

  6. HUMAN-SIMULATING VEHICLE STEERING CONTROL ALGORITHM

    Institute of Scientific and Technical Information of China (English)

    XU Youchun; LI Keqiang; CHANG Ming; CHEN Jun

    2006-01-01

    A new vehicle steering control algorithm is presented. Unlike the traditional methods do,the algorithm uses a sigmoid function to describe the principle of the human driver's steering strategy.Based on this function, a human simulating vehicle steering model, human-simulating steering control(HS) algorithm is designed. In order to improve the adaptability to different environments, a parameter adaptive adjustment algorithm is presented. This algorithm can online modify the value of the key parameters of the HS real time. HS controller is used on a vehicle equipped with computer vision system and computer controlled steering actuator system, the result from the automatic vehicle steering experiment shows that the HS algorithm gives good performance at different speed, even at the maximum speed of 172 km/h.

  7. Chloroplast Redox Poise

    DEFF Research Database (Denmark)

    Steccanella, Verdiana

    the redox status of the plastoquinone pool and chlorophyll biosynthesis. Furthermore, in the plant cell, the equilibrium between redox reactions and ROS signals is also maintained by various balancing mechanisms among which the thioredoxin reductase-thioredoxin system (TR-Trx) stands out as a mediator......The redox state of the chloroplast is maintained by a delicate balance between energy production and consumption and is affected by the need to avoid increased production of reactive oxygen species (ROS). Redox power and ROS generated in the chloroplast are essential for maintaining physiological...... metabolic pathways and for optimizing chloroplast functions. The redox poise of photosynthetic electron transport components like plastoquinone is crucial to initiate signaling cascades and might also be involved in key biosynthetic pathways such as chlorophyll biosynthesis. We, therefore, explored...

  8. Driver behavior following an automatic steering intervention.

    Science.gov (United States)

    Fricke, Nicola; Griesche, Stefan; Schieben, Anna; Hesse, Tobias; Baumann, Martin

    2015-10-01

    The study investigated driver behavior toward an automatic steering intervention of a collision mitigation system. Forty participants were tested in a driving simulator and confronted with an inevitable collision. They performed a naïve drive and afterwards a repeated exposure in which they were told to hold the steering wheel loosely. In a third drive they experienced a false alarm situation. Data on driving behavior, i.e. steering and braking behavior as well as subjective data was assessed in the scenarios. Results showed that most participants held on to the steering wheel strongly or counter-steered during the system intervention during the first encounter. Moreover, subjective data collected after the first drive showed that the majority of drivers was not aware of the system intervention. Data from the repeated drive in which participants were instructed to hold the steering wheel loosely, led to significantly more participants holding the steering wheel loosely and thus complying with the instruction. This study seems to imply that without knowledge and information of the system about an upcoming intervention, the most prevalent driving behavior is a strong reaction with the steering wheel similar to an automatic steering reflex which decreases the system's effectiveness. Results of the second drive show some potential for countermeasures, such as informing drivers shortly before a system intervention in order to prevent inhibiting reactions.

  9. Steering control system for a mobile robot

    Science.gov (United States)

    Kolli, Kaylan C.; Hall, Ernest L.

    1997-09-01

    Automated guided vehicles (AGVs) have many potential applications in manufacturing, medicine, space and defense. The purpose of this paper is to describe the design of a steering mechanism for an autonomous mobile robot. The steering mechanism replaces a manually turned rack and pinion arrangement with a crank mechanism driven by a linear actuator that in turn is powered by a brushless dc motor. The system was modeled, analyzed, and redesigned to meet the requirements. A 486 computer through a 3-axis motion controller supervises the steering control. The steering motor is a brushless dc motor powered by three phase signals. It is run in current loop mode. The steering control system is supervised by a personal computer through a multi-axis motion controller. Testing of these systems has been done in the lab as well as on an outside test track with positive results.

  10. Wireless traffic steering for green cellular networks

    CERN Document Server

    Zhang, Shan; Zhou, Sheng; Niu, Zhisheng; Shen, Xuemin (Sherman)

    2016-01-01

    This book introduces wireless traffic steering as a paradigm to realize green communication in multi-tier heterogeneous cellular networks. By matching network resources and dynamic mobile traffic demand, traffic steering helps to reduce on-grid power consumption with on-demand services provided. This book reviews existing solutions from the perspectives of energy consumption reduction and renewable energy harvesting. Specifically, it explains how traffic steering can improve energy efficiency through intelligent traffic-resource matching. Several promising traffic steering approaches for dynamic network planning and renewable energy demand-supply balancing are discussed. This book presents an energy-aware traffic steering method for networks with energy harvesting, which optimizes the traffic allocated to each cell based on the renewable energy status. Renewable energy demand-supply balancing is a key factor in energy dynamics, aimed at enhancing renewable energy sustainability to reduce on-grid energy consum...

  11. Joint measurability and temporal steering [Invited

    Science.gov (United States)

    Karthik, H. S.; Prabhu Tej, J.; Usha Devi, A. R.; Rajagopal, A. K.

    2015-04-01

    Quintino et. al. (Phys. Rev. Lett. 113, 160402 (2014)) and Uola et. al. (Phys. Rev. Lett. 113, 160403 (2014)) have recently established an intrinsic relation between non-joint measurability and Einstein-Podolsky- Rosen steering. They showed that a set of measurements is incompatible (i.e., not jointly measurable) if and only if it can be used for the demonstration of steering. In this paper, we prove the temporal analog of this result viz., a set of measurements are incompatible if and only if it exhibits temporal steering.

  12. 46 CFR 108.641 - Instructions for changing steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Instructions for changing steering gear. 108.641 Section... steering gear. Instructions stating, in order, the different steps to be taken for changing to emergency and secondary steering gear must be posted in the steering gear room and at each secondary...

  13. Redox control of teratogenesis.

    Science.gov (United States)

    Hansen, Jason M; Harris, Craig

    2013-01-01

    A number of human teratogens elicit their deleterious effects through mechanisms involving the generation of reactive oxygen species (ROS) and oxidative stress. However, classic definitions of oxidative stress do not fully coincide with basic fundamental principles of teratology. Newer definitions of oxidative stress focus on the targeted redox modification of cysteine/thiol functional groups found in the regulatory domains of critical signaling pathway proteins, suggesting that the targeted disruption of signaling through specific redox couples may account for the specificity of teratogen-induced malformations which previously could not be rationalized. Here, we review examples of teratogens that induce ROS and oxidative injury, describe oxidative stress-related teratogenic mechanisms, and provide rationale for developmental periods of sensitivity and species susceptibility. Understanding how chemicals disrupt redox status, induce oxidative stress leading to dysmorphogenesis becomes important to identify potential teratogens and develop therapeutic interventions for attenuation of harmful chemical effects in utero following exposure.

  14. Cancer

    Science.gov (United States)

    ... cancer Non-Hodgkin lymphoma Ovarian cancer Pancreatic cancer Testicular cancer Thyroid cancer Uterine cancer Symptoms Symptoms of cancer ... tumor Obesity Pancreatic cancer Prostate cancer Stomach cancer Testicular cancer Throat or larynx cancer Thyroid cancer Patient Instructions ...

  15. CCCT - NCTN Steering Committees - Clinical Imaging

    Science.gov (United States)

    The Clinical Imaging Steering Committee serves as a forum for the extramural imaging and oncology communities to provide strategic input to the NCI regarding its significant investment in imaging activities in clinical trials.

  16. Performance assessment of PEFP steering magnet

    Energy Technology Data Exchange (ETDEWEB)

    Han, S. H.; Jeo, Y. S. [KAERI, Taejon (Korea, Republic of)

    2003-10-01

    PEFP LEBT uses two solenoid and two steering magnets for the beam position and angle control at the RFQ match point. The dependence of magnetic field and coil temperature on time was assessed and the linearity was also measured.

  17. Glutamate dehydrogenase 1 signals through antioxidant glutathione peroxidase 1 to regulate redox homeostasis and tumor growth.

    Science.gov (United States)

    Jin, Lingtao; Li, Dan; Alesi, Gina N; Fan, Jun; Kang, Hee-Bum; Lu, Zhou; Boggon, Titus J; Jin, Peng; Yi, Hong; Wright, Elizabeth R; Duong, Duc; Seyfried, Nicholas T; Egnatchik, Robert; DeBerardinis, Ralph J; Magliocca, Kelly R; He, Chuan; Arellano, Martha L; Khoury, Hanna J; Shin, Dong M; Khuri, Fadlo R; Kang, Sumin

    2015-02-09

    How mitochondrial glutaminolysis contributes to redox homeostasis in cancer cells remains unclear. Here we report that the mitochondrial enzyme glutamate dehydrogenase 1 (GDH1) is commonly upregulated in human cancers. GDH1 is important for redox homeostasis in cancer cells by controlling the intracellular levels of its product alpha-ketoglutarate and subsequent metabolite fumarate. Mechanistically, fumarate binds to and activates a reactive oxygen species scavenging enzyme glutathione peroxidase 1. Targeting GDH1 by shRNA or a small molecule inhibitor R162 resulted in imbalanced redox homeostasis, leading to attenuated cancer cell proliferation and tumor growth.

  18. New steering mechanism for wheeled mobile robots

    Institute of Scientific and Technical Information of China (English)

    Sidibe Marie Bernard; FU Yi-li; XU He; MA Yu-lin

    2007-01-01

    A new castor wheel mechanism for omni-directional mobile platform is presented. A motion of translation is transformed into a rotation to steer the wheel with the help of a helical path fits into a translation joint and three rollers whose axes are connected to the driving shaft of the wheel. When the path moves in translation it acts on the rollers for steering. The path-roller friction transmission, the wheel kinematics and the maneuverability have been analyzed.

  19. Active steering control strategy for articulated vehicles

    Institute of Scientific and Technical Information of China (English)

    Kyong-il KIM; Hsin GUAN; Bo WANG; Rui GUO; Fan LIANG

    2016-01-01

    To improve maneuverability and stability of articulated vehicles, we design an active steering controller, including tractor and trailer controllers, based on linear quadratic regulator (LQR) theory. First, a three-degree-of-freedom (3-DOF) model of the tractor-trailer with steered trailer axles is built. The simulated annealing particle swarm optimization (SAPSO) algorithm is applied to identify the key parameters of the model under specified vehicle speed and steering wheel angle. Thus, the key pa-rameters of the simplified model can be obtained according to the vehicle conditions using an online look-up table and interpola-tion. Simulation results show that vehicle parameter outputs of the simplified model and TruckSim agree well, thus providing the ideal reference yaw rate for the controller. Then the active steering controller of the tractor and trailer based on LQR is designed to follow the desired yaw rate and minimize their side-slip angle of the center of gravity (CG) at the same time. Finally, simulation tests at both low speed and high speed are conducted based on the TruckSim-Simulink program. The results show significant effects on the active steering controller on improving maneuverability at low speed and lateral stability at high speed for the articulated vehicle. The control strategy is applicable for steering not only along gentle curves but also along sharp curves.

  20. Improvement of motor inertia influence of electric power steering; Dendoshiki power steering no motor kansei no eikyo to hosho

    Energy Technology Data Exchange (ETDEWEB)

    Takehara, S.; Sakamoto, K.; Hanamoto, Y. [Mazda Motor Corp., Hiroshima (Japan); Noritsugu, T. [Okayama University, Okayama (Japan)

    1997-10-01

    Motor inertia of electric power steering affects not only steering characteristics but vehicle dynamics. We have investigated the influence of motor inertia and proposed a feedback strategy to compensate it. Weight of the test vehicle is 1100Kg and the steering system is pinion type electric power steering. By using simulation model and vehicle test, we have realized natural steering maneuvering and stable vehicle dynamics. 4 refs., 11 figs.

  1. Redox Flow Batteries, a Review

    Energy Technology Data Exchange (ETDEWEB)

    Knoxville, U. Tennessee; U. Texas Austin; U, McGill; Weber, Adam Z.; Mench, Matthew M.; Meyers, Jeremy P.; Ross, Philip N.; Gostick, Jeffrey T.; Liu, Qinghua

    2011-07-15

    Redox flow batteries are enjoying a renaissance due to their ability to store large amounts of electrical energy relatively cheaply and efficiently. In this review, we examine the components of redox flow batteries with a focus on understanding the underlying physical processes. The various transport and kinetic phenomena are discussed along with the most common redox couples.

  2. Research on Modeling and Active Steering Control Algorithm for Electric Forklift Steer-by-Wire System

    Directory of Open Access Journals (Sweden)

    Yang Liu

    2016-11-01

    Full Text Available In this paper, according to the structure characteristics of steer-by-wire (SBW system for the TFC20 electric forklift, steering dynamics model and two degree of freedom vehicle model are deduced for SBW forklift. Aiming at the free design features of the angular transmission characteristics in the SBW system of electric forklift, the theory of active steering control strategy is studied. After analyzing the influence factors of the angular trans mission ratio of the steering system, the ideal angular transmission ratio is proposed, which is based on the yaw rate gain invariance. Also, the control strategy of the yaw rate feedback and the full state feedback is studied. The simulation results show that the above strategy is effective for the active steering control; it can improve the operating stability and the response speed of the forklift.

  3. Redox control of GTPases: from molecular mechanisms to functional significance in health and disease.

    Science.gov (United States)

    Heo, Jongyun

    2011-02-15

    Small GTPases, including the proto-oncoprotein Ras and Rho GTPases, are involved in various cellular signaling events. Some of these small GTPases are redox sensitive, including Ras, Rho, Ran, Dexras1, and Rhes GTPases. Thus, the redox-mediated regulation of these GTPases often determines the course of their cellular signaling cascades. This article takes into consideration the application of Marcus theory to potential redox-based molecular mechanisms in the regulation of these redox-sensitive GTPases and the relevance of such mechanisms to a specific redox-sensitive motif. The discussion also takes into account various diseases, including cancers, heart, and neuronal disorders, that are often linked with the dysregulation of the redox signaling cascades associated with these redox-sensitive GTPases.

  4. Redox-capacitor to connect electrochemistry to redox-biology.

    Science.gov (United States)

    Kim, Eunkyoung; Leverage, W Taylor; Liu, Yi; White, Ian M; Bentley, William E; Payne, Gregory F

    2014-01-07

    It is well-established that redox-reactions are integral to biology for energy harvesting (oxidative phosphorylation), immune defense (oxidative burst) and drug metabolism (phase I reactions), yet there is emerging evidence that redox may play broader roles in biology (e.g., redox signaling). A critical challenge is the need for tools that can probe biologically-relevant redox interactions simply, rapidly and without the need for a comprehensive suite of analytical methods. We propose that electrochemistry may provide such a tool. In this tutorial review, we describe recent studies with a redox-capacitor film that can serve as a bio-electrode interface that can accept, store and donate electrons from mediators commonly used in electrochemistry and also in biology. Specifically, we (i) describe the fabrication of this redox-capacitor from catechols and the polysaccharide chitosan, (ii) discuss the mechanistic basis for electron exchange, (iii) illustrate the properties of this redox-capacitor and its capabilities for promoting redox-communication between biology and electrodes, and (iv) suggest the potential for enlisting signal processing strategies to "extract" redox information. We believe these initial studies indicate broad possibilities for enlisting electrochemistry and signal processing to acquire "systems level" redox information from biology.

  5. Redox theory of aging.

    Science.gov (United States)

    Jones, Dean P

    2015-08-01

    Metazoan genomes encode exposure memory systems to enhance survival and reproductive potential by providing mechanisms for an individual to adjust during lifespan to environmental resources and challenges. These systems are inherently redox networks, arising during evolution of complex systems with O2 as a major determinant of bioenergetics, metabolic and structural organization, defense, and reproduction. The network structure decreases flexibility from conception onward due to differentiation and cumulative responses to environment (exposome). The redox theory of aging is that aging is a decline in plasticity of genome-exposome interaction that occurs as a consequence of execution of differentiation and exposure memory systems. This includes compromised mitochondrial and bioenergetic flexibility, impaired food utilization and metabolic homeostasis, decreased barrier and defense capabilities and loss of reproductive fidelity and fecundity. This theory accounts for hallmarks of aging, including failure to maintain oxidative or xenobiotic defenses, mitochondrial integrity, proteostasis, barrier structures, DNA repair, telomeres, immune function, metabolic regulation and regenerative capacity.

  6. Redox theory of aging

    Directory of Open Access Journals (Sweden)

    Dean P. Jones

    2015-08-01

    Full Text Available Metazoan genomes encode exposure memory systems to enhance survival and reproductive potential by providing mechanisms for an individual to adjust during lifespan to environmental resources and challenges. These systems are inherently redox networks, arising during evolution of complex systems with O2 as a major determinant of bioenergetics, metabolic and structural organization, defense, and reproduction. The network structure decreases flexibility from conception onward due to differentiation and cumulative responses to environment (exposome. The redox theory of aging is that aging is a decline in plasticity of genome–exposome interaction that occurs as a consequence of execution of differentiation and exposure memory systems. This includes compromised mitochondrial and bioenergetic flexibility, impaired food utilization and metabolic homeostasis, decreased barrier and defense capabilities and loss of reproductive fidelity and fecundity. This theory accounts for hallmarks of aging, including failure to maintain oxidative or xenobiotic defenses, mitochondrial integrity, proteostasis, barrier structures, DNA repair, telomeres, immune function, metabolic regulation and regenerative capacity.

  7. Microfluidic redox battery.

    Science.gov (United States)

    Lee, Jin Wook; Goulet, Marc-Antoni; Kjeang, Erik

    2013-07-01

    A miniaturized microfluidic battery is proposed, which is the first membraneless redox battery demonstrated to date. This unique concept capitalizes on dual-pass flow-through porous electrodes combined with stratified, co-laminar flow to generate electrical power on-chip. The fluidic design is symmetric to allow for both charging and discharging operations in forward, reverse, and recirculation modes. The proof-of-concept device fabricated using low-cost materials integrated in a microfluidic chip is shown to produce competitive power levels when operated on a vanadium redox electrolyte. A complete charge/discharge cycle is performed to demonstrate its operation as a rechargeable battery, which is an important step towards providing sustainable power to lab-on-a-chip and microelectronic applications.

  8. Distinct Redox Profiles of Selected Human Prostate Carcinoma Cell Lines: Implications for Rational Design of Redox Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Chaiswing, Luksana [Department of Pathology and Laboratory Medicine, School of Medicine and Public Health, University of Wisconsin, 1111 Highland Ave., WIMR 7168, Madison, WI 53705 (United States); Zhong, Weixiong; Oberley, Terry D., E-mail: toberley@wisc.edu [Department of Pathology and Laboratory Medicine, School of Medicine and Public Health, University of Wisconsin, 1111 Highland Ave., WIMR 7168, Madison, WI 53705 (United States); Pathology and Laboratory Medicine Service, William S. Middleton Memorial Veterans Hospital, Rm A-35, 2500 Overlook Terrace, Madison, WI 53705 (United States)

    2011-09-13

    The effects of several cancer chemotherapeutic drugs and radiation are mediated, at least in part, by oxidative stress. To better understand this process, we analyzed certain biochemical properties affecting reduction-oxidation (redox) balance in normal prostate epithelial cells and several prostate cancer cell lines. Highly aggressive androgen-independent prostate cancer PC3 cells demonstrated significantly higher levels of total antioxidant capacity (AC) and intra- and extracellular glutathione (GSH)/glutathione disulfide (GSSG) ratios when compared with normal prostate epithelial PrEC cells. WPE1-NB26 cells, a prostate cancer cell line derived from immortalized RWPE1 human prostate epithelial cells, demonstrated significantly higher levels of total AC and intra- and extracellular GSH/GSSG ratios, but lower levels of intracellular reactive oxygen/nitrogen species and lipid peroxidation compared with RWPE1 cells. LNCaP-C4-2 cells, a more aggressive prostate cancer derived from less aggressive androgen-responsive LNCaP cells, exhibited higher levels of AC and extracellular GSH/GSSG ratio when compared to LNCaP cells. Specific cell types showed distinct cytotoxic responses to redox-modulating compounds. WPE1-NB26 cells were more sensitive to phenethyl isothiocyanate and tumor necrosis factor (TNF) than RWPE1 cells, while PC3 cells were more sensitive to TNF than PrEC cells. These results are consistent with the hypothesis that cancer cell redox state may modulate responses to redox-modulating therapeutic regimens.

  9. Distinct Redox Profiles of Selected Human Prostate Carcinoma Cell Lines: Implications for Rational Design of Redox Therapy

    Directory of Open Access Journals (Sweden)

    Luksana Chaiswing

    2011-09-01

    Full Text Available The effects of several cancer chemotherapeutic drugs and radiation are mediated, at least in part, by oxidative stress. To better understand this process, we analyzed certain biochemical properties affecting reduction-oxidation (redox balance in normal prostate epithelial cells and several prostate cancer cell lines. Highly aggressive androgen-independent prostate cancer PC3 cells demonstrated significantly higher levels of total antioxidant capacity (AC and intra- and extracellular glutathione (GSH/glutathione disulfide (GSSG ratios when compared with normal prostate epithelial PrEC cells. WPE1-NB26 cells, a prostate cancer cell line derived from immortalized RWPE1 human prostate epithelial cells, demonstrated significantly higher levels of total AC and intra- and extracellular GSH/GSSG ratios, but lower levels of intracellular reactive oxygen/nitrogen species and lipid peroxidation compared with RWPE1 cells. LNCaP-C4-2 cells, a more aggressive prostate cancer derived from less aggressive androgen-responsive LNCaP cells, exhibited higher levels of AC and extracellular GSH/GSSG ratio when compared to LNCaP cells. Specific cell types showed distinct cytotoxic responses to redox-modulating compounds. WPE1-NB26 cells were more sensitive to phenethyl isothiocyanate and tumor necrosis factor (TNF than RWPE1 cells, while PC3 cells were more sensitive to TNF than PrEC cells. These results are consistent with the hypothesis that cancer cell redox state may modulate responses to redox-modulating therapeutic regimens.

  10. Ediacaran Redox Fluctuations

    Science.gov (United States)

    Sahoo, S. K.; Jiang, G.; Planavsky, N. J.; Kendall, B.; Owens, J. D.; Anbar, A. D.; Lyons, T. W.

    2013-12-01

    Evidence for pervasive oxic conditions, and likely even deep ocean oxygenation has been documented at three intervals in the lower (ca. 632 Ma), middle (ca. 580 Ma) and upper (ca. 551 Ma) Ediacaran. The Doushantuo Formation in South China hosts large enrichments of redox-sensitive trace element (e.g., molybdenum, vanadium and uranium) in anoxic shales, which are indicative of a globally oxic ocean-atmosphere system. However, ocean redox conditions between these periods continue to be a topic of debate and remain elusive. We have found evidence for widespread anoxic conditions through much of the Ediacaran in the deep-water Wuhe section in South China. During most of the Ediacaran-early Cambrian in basinal sections is characterized by Fe speciation data and pyrite morphologies that indicate deposition under euxinic conditions with near-crustal enrichments of redox-sensitive element and positive pyrite-sulfur isotope values, which suggest low levels of marine sulfate and widespread euxinia. Our work reinforces an emerging view that the early Earth, including the Ediacaran, underwent numerous rises and falls in surface oxidation state, rather than a unidirectional rise as originally imagined. The Ediacaran ocean thus experienced repetitive expansion and contraction of marine chalcophilic trace-metal levels that may have had fundamental impact on the slow evolution of early animals and ecosystems. Further, this framework forces us to re-examine the relationship between Neoproterozoic oxygenation and metazoan diversification. Varying redox conditions through the Cryogenian and Ediacaran may help explain molecular clock and biomarker evidence for an early appearance and initial diversification of metazoans but with a delay in the appearance of most major metazoan crown groups until close to Ediacaran-Cambrian boundary.

  11. No-cloning of quantum steering

    Science.gov (United States)

    Chiu, Ching-Yi; Lambert, Neill; Liao, Teh-Lu; Nori, Franco; Li, Che-Ming

    2016-06-01

    Einstein-Podolsky-Rosen (EPR) steering allows two parties to verify their entanglement, even if one party’s measurements are untrusted. This concept has not only provided new insights into the nature of non-local spatial correlations in quantum mechanics, but also serves as a resource for one-sided device-independent quantum information tasks. Here, we investigate how EPR steering behaves when one-half of a maximally entangled pair of qudits (multidimensional quantum systems) is cloned by a universal cloning machine. We find that EPR steering, as verified by a criterion based on the mutual information between qudits, can only be found in one of the copy subsystems but not both. We prove that this is also true for the single-system analogue of EPR steering. We find that this restriction, which we term ‘no-cloning of quantum steering’, elucidates the physical reason why steering can be used to secure sources and channels against cloning-based attacks when implementing quantum communication and quantum computation protocols.

  12. Research on Torque Ratio Based on the Steering Wheel Torque Characteristic for Steer-by-Wire System

    OpenAIRE

    Yandong Han; Lei He; Xiang Wang; Changfu Zong

    2014-01-01

    Steer-by-wire system can improve the performance of vehicle handling stability. Removing the mechanical linkages between the front wheels and the steering wheel leads to a key technique of force feedback for steer-by-wire system. In view of the characteristic of variable torque transmission ratio for steer-by-wire system, this paper proposes a method for designing torque ratio based on the steering wheel torque characteristic for steer-by-wire system. It converts the torque ratio design into ...

  13. Stability analysis of automobile driver steering control

    Science.gov (United States)

    Allen, R. W.

    1981-01-01

    In steering an automobile, the driver must basically control the direction of the car's trajectory (heading angle) and the lateral deviation of the car relative to a delineated pathway. A previously published linear control model of driver steering behavior which is analyzed from a stability point of view is considered. A simple approximate expression for a stability parameter, phase margin, is derived in terms of various driver and vehicle control parameters, and boundaries for stability are discussed. A field test study is reviewed that includes the measurement of driver steering control parameters. Phase margins derived for a range of vehicle characteristics are found to be generally consistent with known adaptive properties of the human operator. The implications of these results are discussed in terms of driver adaptive behavior.

  14. Steering object-oriented computations with Python

    Energy Technology Data Exchange (ETDEWEB)

    Yang, T.-Y.B.; Dubois, P.F.; Furnish, G. [Lawrence Livermore National Lab., CA (United States); Beazley, D.M. [Utah Univ., Salt Lake City, UT (United States). Dept. of Computer Science

    1996-10-01

    We have described current approaches and future plans for steering C++ application, running Python on parallel platforms, and combination of Tk interface and Python interpreter in steering computations. In addition, there has been significant enhancement in the Gist module. Tk mega widgets has been implemented for a few physics applications. We have also written Python interface to SIJLO, a data storage package used as an interface to a visualization system named MeshTv. Python is being used to control large-scale simulations (molecular dynamics in particular) running on the CM-5 and T3D at LANL as well. A few other code development projects at LLNL are either using or considering Python as their steering shells. In summary, the merits of Python have been appreciated by more and more people in the scientific computation community.

  15. Tunable beam steering enabled by graphene metamaterials.

    Science.gov (United States)

    Orazbayev, B; Beruete, M; Khromova, I

    2016-04-18

    We demonstrate tunable mid-infrared (MIR) beam steering devices based on multilayer graphene-dielectric metamaterials. The effective refractive index of such metamaterials can be manipulated by changing the chemical potential of each graphene layer. This can arbitrarily tailor the spatial distribution of the phase of the transmitted beam, providing mechanisms for active beam steering. Three different beam steerer (BS) designs are discussed: a graded-index (GRIN) graphene-based metamaterial block, an array of metallic waveguides filled with graphene-dielectric metamaterial and an array of planar waveguides created in a graphene-dielectric metamaterial block with a specific spatial profile of graphene sheets doping. The performances of the BSs are numerically analyzed, showing the tunability of the proposed designs for a wide range of output angles (up to approximately 70°). The proposed graphene-based tunable beam steering can be used in tunable transmitter/receiver modules for infrared imaging and sensing.

  16. Online optimized hysteresis-based steering feel model for steer-by-wire systems

    Directory of Open Access Journals (Sweden)

    Ahmet Kirli

    2016-06-01

    Full Text Available In rubber-wheeled road vehicles, the mechanical connection between steering wheel and front wheels provides steering-related feedback to the driver. The torque fed back to the driver through the steering linkages and steering wheel, which is called steering feel, helps the driver in controlling the vehicle. The torque feedback is reproduced via artificial methods in steer-by-wire systems due to the lack of mechanical connection. In this work, in order to minimize the physical workload and the lateral acceleration under the consideration of handling performance, optimization of a hysteresis-based steering feel has been studied. A 2-degree-of-freedom bicycle model based on the magic formula tire model has been used for simulations and hardware-in-the-loop experiments. A mathematical model is proposed in order to create an adaptive model-based optimization of the hysteresis parameters simultaneously while driving. A hardware-in-the-loop experimental setup has been used for the driving tests. The weave and the double-lane change tests have been performed with different drivers in order to demonstrate and quantify the optimization methods that are presented in this work.

  17. Influence of different shoulder-elbow configurations on steering precision and steering velocity in automotive context.

    Science.gov (United States)

    Schmidt, Susanne; Seiberl, Wolfgang; Schwirtz, Ansgar

    2015-01-01

    Ergonomic design requirements are needed to develop optimum vehicle interfaces for the driver. The majority of the current specifications consider only anthropometric conditions and subjective evaluations of comfort. This paper examines specific biomechanical aspects to improve the current ergonomic requirements. Therefore, a research which involved 40 subjects was carried out to obtain more knowledge in the field of steering movement while driving a car. Five different shoulder-elbow joint configurations were analyzed using a driving simulator to find optimum posture for driving in respect of steering precision and steering velocity. Therefore, a 20 s precision test and a test to assess maximum steering velocity over a range of 90° steering motion have been conducted. The results show that driving precision, as well as maximum steering velocity, are significantly increased in mid-positions (elbow angles of 95° and 120°) compared to more flexed (70°) or extended (145° and 160°) postures. We conclude that driver safety can be enhanced by implementing these data in the automotive design process because faster and highly precise steering can be important during evasive actions and in accident situations. In addition, subjective comfort rating, analyzed with questionnaires, confirmed experimental results.

  18. Redox cycling of endogenous copper by ferulic acid leads to cellular DNA breakage and consequent cell death: A putative cancer chemotherapy mechanism.

    Science.gov (United States)

    Sarwar, Tarique; Zafaryab, Md; Husain, Mohammed Amir; Ishqi, Hassan Mubarak; Rehman, Sayeed Ur; Rizvi, M Moshahid Alam; Tabish, Mohammad

    2015-12-01

    Ferulic acid (FA) is a plant polyphenol showing diverse therapeutic effects against cancer, diabetes, cardiovascular and neurodegenerative diseases. FA is a known antioxidant at lower concentrations, however at higher concentrations or in the presence of metal ions such as copper, it may act as a pro-oxidant. It has been reported that copper levels are significantly raised in different malignancies. Cancer cells are under increased oxidative stress as compared to normal cells. Certain therapeutic substances like polyphenols can further increase this oxidative stress and kill cancer cells without affecting the proliferation of normal cells. Through various in vitro experiments we have shown that the pro-oxidant properties of FA are enhanced in the presence of copper. Comet assay demonstrated the ability of FA to cause oxidative DNA breakage in human peripheral lymphocytes which was ameliorated by specific copper-chelating agent such as neocuproine and scavengers of ROS. This suggested the mobilization of endogenous copper in ROS generation and consequent DNA damage. These results were further validated through cytotoxicity experiments involving different cell lines. Thus, we conclude that such a pro-oxidant mechanism involving endogenous copper better explains the anticancer activities of FA. This would be an alternate non-enzymatic, and copper-mediated pathway for the cytotoxic activities of FA where it can selectively target cancer cells with elevated levels of copper and ROS.

  19. Disulfiram/copper causes redox-related proteotoxicity and concomitant heat shock response in ovarian cancer cells that is augmented by auranofin-mediated thioredoxin inhibition

    Science.gov (United States)

    Papaioannou, Margarita; Mylonas, Ioannis; Kast, Richard E.; Brüning, Ansgar

    2014-01-01

    A valuable strategy to develop new therapeutic options for a variety of diseases has been the identification of new targets and applications for already approved drugs, the so-called drug repositioning. Recurrent ovarian cancer is a nearly incurable malignancy for which new and effective treatments are urgently needed. The alcohol-deterring drug disulfiram has been shown to cause preferential cell death in a variety of cancer cells. In this study, it is shown that disulfiram mediates effective cell death in ovarian cancer cells by promoting a pro-oxidative intracellular environment in a copper-dependent mechanism. Within few hours of application, disulfiram caused irreversible cell damage associated with pronounced induction of the inducible heat shock proteins HSP70, HSP40, and HSP32. The small heat shock protein HSP27 was found to be covalently dimerized via oxidized disulfide bonds and precipitated in para-nuclear protein aggregates. Simultaneous inhibition of the cellular thioredoxin system by auranofin further enhanced the cytotoxic effect of disulfiram. These data indeed indicate that the combination of two approved drugs, the anti-alcoholic disulfiram and the anti-rheumatic auranofin, may be of interest for the treatment of recurrent and genotoxic drug-resistant ovarian cancer by inducing a proteotoxic cell death mechanism. PMID:25593981

  20. Reciprocal Control of the Circadian Clock and Cellular Redox State - a Critical Appraisal.

    Science.gov (United States)

    Putker, Marrit; O'Neill, John Stuart

    2016-01-01

    Redox signalling comprises the biology of molecular signal transduction mediated by reactive oxygen (or nitrogen) species. By specific and reversible oxidation of redox-sensitive cysteines, many biological processes sense and respond to signals from the intracellular redox environment. Redox signals are therefore important regulators of cellular homeostasis. Recently, it has become apparent that the cellular redox state oscillates in vivo and in vitro, with a period of about one day (circadian). Circadian time-keeping allows cells and organisms to adapt their biology to resonate with the 24-hour cycle of day/night. The importance of this innate biological time-keeping is illustrated by the association of clock disruption with the early onset of several diseases (e.g. type II diabetes, stroke and several forms of cancer). Circadian regulation of cellular redox balance suggests potentially two distinct roles for redox signalling in relation to the cellular clock: one where it is regulated by the clock, and one where it regulates the clock. Here, we introduce the concepts of redox signalling and cellular timekeeping, and then critically appraise the evidence for the reciprocal regulation between cellular redox state and the circadian clock. We conclude there is a substantial body of evidence supporting circadian regulation of cellular redox state, but that it would be premature to conclude that the converse is also true. We therefore propose some approaches that might yield more insight into redox control of cellular timekeeping.

  1. Experimental Quantification of Asymmetric Einstein-Podolsky-Rosen Steering.

    Science.gov (United States)

    Sun, Kai; Ye, Xiang-Jun; Xu, Jin-Shi; Xu, Xiao-Ye; Tang, Jian-Shun; Wu, Yu-Chun; Chen, Jing-Ling; Li, Chuan-Feng; Guo, Guang-Can

    2016-04-22

    Einstein-Podolsky-Rosen (EPR) steering describes the ability of one observer to nonlocally "steer" the other observer's state through local measurements. EPR steering exhibits a unique asymmetric property; i.e., the steerability can differ between observers, which can lead to one-way EPR steering in which only one observer obtains steerability in the steering process. This property is inherently different from the symmetric concepts of entanglement and Bell nonlocality, and it has attracted increasing interest. Here, we experimentally demonstrate asymmetric EPR steering for a class of two-qubit states in the case of two measurement settings. We propose a practical method to quantify the steerability. We then provide a necessary and sufficient condition for EPR steering and clearly demonstrate one-way EPR steering. Our work provides new insight into the fundamental asymmetry of quantum nonlocality and has potential applications in asymmetric quantum information processing.

  2. Self-steering partially coherent beams

    Science.gov (United States)

    Chen, Yahong; Ponomarenko, Sergey A.; Cai, Yangjian

    2017-01-01

    We introduce a class of shape-invariant partially coherent beams with a moving guiding center which we term self-steering partially coherent beams. The guiding center of each such beam evolves along a straight line trajectory which can be engineered to make any angle with the x-axis. We show that the straight line trajectory of the guiding center is the only option in free space due to the linear momentum conservation. We experimentally generate a particular subclass of new beams, self-steering Gaussian Schell beams and argue that they can find applications for mobile target tracing and trapped micro- and/or nanoparticle transport. PMID:28051164

  3. A control theory approach to clock steering techniques.

    Science.gov (United States)

    Farina, Marcello; Galleani, Lorenzo; Tavella, Patrizia; Bittanti, Sergio

    2010-10-01

    Several clock and time scale steering methods have been developed according to different viewpoints by various time laboratories. By resorting to control theory ideas, we propose a common theoretical framework encompassing these methods. A comparison of the most common steering methodologies, namely, the classical steering approach, the GPS bang-bang method, and the linear quadratic Gaussian technique, is carried out. We believe that the use of control theory methods can potentially lead to a better understanding of clock steering algorithms.

  4. Sarsaparilla (Smilax Glabra Rhizome) Extract Inhibits Cancer Cell Growth by S Phase Arrest, Apoptosis, and Autophagy via Redox-Dependent ERK1/2 Pathway.

    Science.gov (United States)

    She, Tiantian; Qu, Like; Wang, Lixin; Yang, Xingxin; Xu, Shuo; Feng, Junnan; Gao, Yujing; Zhao, Chuanke; Han, Yong; Cai, Shaoqing; Shou, Chengchao

    2015-05-01

    Cancer is still the major cause of death across the world. Regular approaches cannot effectively solve the emerging problems, including drug/radiation resistance, side effects, and therapeutic ineffectiveness. Natural dietary supplements have shown effectiveness in the prevention and treatment of cancer. Sarsaparilla (Smilax Glabra Rhizome) has growth-inhibitory effects on several cancer cell lines in vitro and in vivo, with little toxicity on normal cells. However, the mechanism underlying its function remains elusive. In the present study, we examined the anticancer activity of the supernatant of the water-soluble extract (SW) from sarsaparilla. Liquid chromatography/mass spectrometry-ion trap-time-of-flight (LC/MS-IT-TOF) analysis identified flavonoids, alkaloids, and phenylpropanoids as the major bioactive components of SW. SW was shown to markedly inhibit the growth of a broad spectrum of cancer cell lines in the in vitro and in vivo assays. S phase arrest, autophagy, or/and apoptosis were partly responsible for SW-induced growth inhibition. Results of microarray analysis and validation by quantitative RT-PCR indicated the involvement of oxidative stress and the MAPK1 pathway in SW-treated cells. We further found that SW destroyed intracellular-reduced glutathione/oxidized glutathione (GSH/GSSG) balance, and supplement with N-acetylcysteine (NAC) or glutathione (GSH) significantly antagonized SW-induced S phase arrest, apoptosis, and autophagy. In addition, SW-induced GSH/GSSG imbalance activated the ERK1/2 pathway, which contributed to SW-induced S phase arrest, apoptosis, autophagy, and resultant growth-inhibitory effect. Together, our results provide a molecular basis for sarsaparilla as an anticancer agent.

  5. Effect of 3-bromopyruvate acid on the redox equilibrium in non-invasive MCF-7 and invasive MDA-MB-231 breast cancer cells.

    Science.gov (United States)

    Kwiatkowska, Ewa; Wojtala, Martyna; Gajewska, Agnieszka; Soszyński, Mirosław; Bartosz, Grzegorz; Sadowska-Bartosz, Izabela

    2016-02-01

    Novel approaches to cancer chemotherapy employ metabolic differences between normal and tumor cells, including the high dependence of cancer cells on glycolysis ("Warburg effect"). 3-Bromopyruvate (3-BP), inhibitor of glycolysis, belongs to anticancer drugs basing on this principle. 3-BP was tested for its capacity to kill human non-invasive MCF-7 and invasive MDA-MB-231 breast cancer cells. We found that 3-BP was more toxic for MDA-MB-231 cells than for MCF-7 cells. In both cell lines, a statistically significant decrease of ATP and glutathione was observed in a time- and 3-BP concentration-dependent manner. Transient increases in the level of reactive oxygen species and reactive oxygen species was observed, more pronounced in MCF-7 cells, followed by a decreasing tendency. Activities of glutathione peroxidase, glutathione reductase (GR) and glutathione S-transferase (GST) decreased in 3-BP treated MDA-MB-231 cells. For MCF-7 cells decreases of GR and GST activities were noted only at the highest concentration of 3-BP.These results point to induction of oxidative stress by 3-BP via depletion of antioxidants and inactivation of antioxidant enzymes, more pronounced in MDA-MB-231 cells, more sensitive to 3-BP.

  6. Alterations in the expression of the apurinic/apyrimidinic endonuclease-1/redox factor-1 (APE1/Ref-1) in human ovarian cancer and indentification of the therapeutic potential of APE1/Ref-1 inhibitor.

    Science.gov (United States)

    Zhang, Ying; Wang, Jian; Xiang, Debing; Wang, Dong; Xin, Xiaoyan

    2009-11-01

    Resistance to platinum is a major limitation for the treatment of ovarian cancer. In an effort to overcome the platinum resistance problem in ovarian cancer treatment, we explored the correlation between cisplatin resistance and the human AP endonuclease (APE1 or Ref-1). APE1/Ref-1 is a multifunctional protein that is not only an essential enzyme in base excision repair pathway, but also acts as a major redox-signaling factor that has a wide variety of important cellular functions including transcription factor regulation, oxidative signaling and cell cycle control. In this study, we examined APE1/Ref-1 expression by immunohistochemistry in sections of ovarian cancers from 78 patients who were administered standard adjuvant chemotherapy based on platinum post-operatively. Altered levels and subcellular APE1/Ref-1 expression was found in patients not responding to platinum-based chemotherapy comparing with those who responded to platinum-based chemotherapy. Meanwhile, we detected the APE1/Ref-1 expression in A2780 and CP70 cell lines which have different sensitivity to cisplatin. We found similar altered APE1/Ref-1 expression in them. We hypothesized that the APE1/Ref-1 expression is responsible in part for the cisplatin resistance. To answer this hypothesis, we decreased the APE1/Ref-1 level by silencing RNA targeting technology in A2780 and CP70 cell lines. The A2780 cells treated with APE1-siRNA had IC50 values ranging from 6.70 to 1.74 microM cisplatin compared with 15.81 microM for control A2780 cells. The CP70 cells treated with APE1-siRNA had 1.62-4.63-fold enhancement in cisplatin sensitivity. The apoptosis assays using TUNEL analysis showed that decreased APE1/Ref-1 level resulted in increased apoptosis levels in A2780 and CP70 cell lines compared with the control-treated cells. These data suggest that APE1/Ref-1 levels play an important role in the sensitization of ovarian cancer cells to apoptosis. In vitro studies revealed that it is possible to

  7. 9 CFR 78.6 - Steers and spayed heifers.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Steers and spayed heifers. 78.6... Restrictions on Interstate Movement of Cattle Because of Brucellosis § 78.6 Steers and spayed heifers. Steers and spayed heifers may be moved interstate without restriction under this subpart....

  8. 9 CFR 78.21 - Bison steers and spayed heifers.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Bison steers and spayed heifers. 78.21... Restrictions on Interstate Movement of Bison Because of Brucellosis § 78.21 Bison steers and spayed heifers. Bison steers and spayed heifers may be moved interstate without restriction under this subpart....

  9. Working paper on public steering of privately owned sports facilities

    DEFF Research Database (Denmark)

    Iversen, Evald Bundgård

    This short paper discusses how municipalities can steer privately owned sports facilities. Firstly I analyse why steering of privately owned facilities is an interesting subject. Secondly I discuss what the advantages and drawbacks of using different approaches for steering sports facilities are....

  10. 46 CFR 61.20-1 - Steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Steering gear. 61.20-1 Section 61.20-1 Shipping COAST... Periodic Tests of Machinery and Equipment § 61.20-1 Steering gear. (a) The marine inspector must inspect the steering gear at each inspection for certification for vessels whose Certificate of...

  11. 46 CFR 167.65-25 - Steering gear tests.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Steering gear tests. 167.65-25 Section 167.65-25... SHIPS Special Operating Requirements § 167.65-25 Steering gear tests. On all nautical school ships making voyages of more than 48 hours' duration, the entire steering gear, the whistle, the means...

  12. 46 CFR 58.25-20 - Piping for steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Piping for steering gear. 58.25-20 Section 58.25-20... MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-20 Piping for steering gear. (a) Pressure piping must... actuating system including the reservoir. The storage tank must be permanently connected by piping so...

  13. Parametrizable cameras for 3D computational steering

    NARCIS (Netherlands)

    Mulder, J.D.; Wijk, J.J. van

    1997-01-01

    We present a method for the definition of multiple views in 3D interfaces for computational steering. The method uses the concept of a point-based parametrizable camera object. This concept enables a user to create and configure multiple views on his custom 3D interface in an intuitive graphical man

  14. Steered wheel for the support and/or steering of a vehicle, particularly hovercraft

    Energy Technology Data Exchange (ETDEWEB)

    Duell, H.J.; Kirchner, G.

    1977-04-07

    The invention concerns a steered wheel for the support or steering of a hovercraft, whose wheel suspension is provided with an eccentric journal for automatic setting in the direction of travel. So that the vehicle will not leave its track during changes of direction when the wheel is turned around the eccentric axis, according to the invention the wheel is supported on movable bearings at the journal in the direction of the driving axle.

  15. Einstein-Podolsky-Rosen steering inequalities from entropic uncertainty relations

    Science.gov (United States)

    Schneeloch, James; Broadbent, Curtis J.; Walborn, Stephen P.; Cavalcanti, Eric G.; Howell, John C.

    2013-06-01

    We use entropic uncertainty relations to formulate inequalities that witness Einstein-Podolsky-Rosen (EPR)-steering correlations in diverse quantum systems. We then use these inequalities to formulate symmetric EPR-steering inequalities using the mutual information. We explore the differing natures of the correlations captured by one-way and symmetric steering inequalities and examine the possibility of exclusive one-way steerability in two-qubit states. Furthermore, we show that steering inequalities can be extended to generalized positive operator-valued measures, and we also derive hybrid steering inequalities between alternate degrees of freedom.

  16. Direct electrochemistry of redox proteins.

    NARCIS (Netherlands)

    Heering, H.A.

    1995-01-01

    The goal of the project was to obtain more detailed insight in interactions between redox proteins and solid electrodes and the mechanisms of electron transfer. In addition to this, the influence of the protein environment on the redox properties of the active site and the possible influence of the

  17. Enhancement of Selectivity of an Organometallic Anticancer Agent by Redox Modulation.

    Science.gov (United States)

    Romero-Canelón, Isolda; Mos, Magdalena; Sadler, Peter J

    2015-10-08

    Combination with redox modulators can potentiate the anticancer activity and maximize the selectivity of organometallic complexes with redox-based mechanisms of action. We show that nontoxic doses of l-buthionine sulfoximine increase the selectivity of organo-Os complex FY26 for human ovarian cancer cells versus normal lung fibroblasts to 63-fold. This increase is not due to changes in the mechanism of action of FY26 but to the decreased response of cancer cells to oxidative stress.

  18. Improving Einstein–Podolsky–Rosen steering inequalities with state information

    Energy Technology Data Exchange (ETDEWEB)

    Schneeloch, James [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Broadbent, Curtis J. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Rochester Theory Center, University of Rochester, Rochester, NY 14627 (United States); Howell, John C. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States)

    2014-02-01

    We discuss the relationship between entropic Einstein–Podolsky–Rosen (EPR)-steering inequalities and their underlying uncertainty relations along with the hypothesis that improved uncertainty relations lead to tighter EPR-steering inequalities. In particular, we discuss how using information about the state of a quantum system affects one's ability to witness EPR-steering. As an example, we consider the recent improvement to the entropic uncertainty relation between pairs of discrete observables (Berta et al., 2010 [10]). By considering the assumptions that enter into the development of a steering inequality, we derive correct steering inequalities from these improved uncertainty relations and find that they are identical to ones already developed (Schneeloch et al., 2013 [9]). In addition, we consider how one can use state information to improve our ability to witness EPR-steering, and develop a new continuous variable symmetric EPR-steering inequality as a result.

  19. Improving Einstein-Podolsky-Rosen steering inequalities with state information

    Science.gov (United States)

    Schneeloch, James; Broadbent, Curtis J.; Howell, John C.

    2014-02-01

    We discuss the relationship between entropic Einstein-Podolsky-Rosen (EPR)-steering inequalities and their underlying uncertainty relations along with the hypothesis that improved uncertainty relations lead to tighter EPR-steering inequalities. In particular, we discuss how using information about the state of a quantum system affects one's ability to witness EPR-steering. As an example, we consider the recent improvement to the entropic uncertainty relation between pairs of discrete observables (Berta et al., 2010 [10]). By considering the assumptions that enter into the development of a steering inequality, we derive correct steering inequalities from these improved uncertainty relations and find that they are identical to ones already developed (Schneeloch et al., 2013 [9]). In addition, we consider how one can use state information to improve our ability to witness EPR-steering, and develop a new continuous variable symmetric EPR-steering inequality as a result.

  20. Active disturbance rejection control in steering by wire haptic systems.

    Science.gov (United States)

    Rodriguez-Angeles, A; Garcia-Antonio, J A

    2014-07-01

    This paper introduces a steering by wired haptic system based on disturbance rejection control techniques. High gain Generalized Proportional Integral (GPI) observers are considered for the estimation of tire and steering wheel dynamic disturbances. These disturbances are on line canceled to ensure tracking between the commanded steering wheel angle and the tire orientation angle. The estimated disturbances at the steering rack are feedback to the steering wheel to provide a haptic interface with the driver. The overall system behaves as a bilateral master-slave system. Very few sensors and minimum knowledge of the dynamic model are required. Experimental results are presented on a prototype platform that consists on: (1) half of the steering rack of a beetle VW vehicle, (2) a steering wheel.

  1. Research on Torque Ratio Based on the Steering Wheel Torque Characteristic for Steer-by-Wire System

    Directory of Open Access Journals (Sweden)

    Yandong Han

    2014-01-01

    Full Text Available Steer-by-wire system can improve the performance of vehicle handling stability. Removing the mechanical linkages between the front wheels and the steering wheel leads to a key technique of force feedback for steer-by-wire system. In view of the characteristic of variable torque transmission ratio for steer-by-wire system, this paper proposes a method for designing torque ratio based on the steering wheel torque characteristic for steer-by-wire system. It converts the torque ratio design into equivalent assist torque design by analyzing their relationship. It achieves the torque ratio design at different conditions based on the negative equivalent assist torque characteristic curve. Simulations and vehicle experiments are conducted by the proposed method, and the results show that the design goal has been achieved and the steering wheel torque characteristic obtained is very similar to that of the reference car.

  2. Improvement of Steering Feel of Electric Power Steering System with Variable Gear Transmission System Using Decoupling Control

    Science.gov (United States)

    Morita, Yoshifumi; Yokoi, Akitoshi; Iwasaki, Makoto; Ukai, Hiroyuki; Matsui, Nobuyuki; Ito, Norihisa; Uryu, Nobuhiko; Mukai, Yasuhiko

    In this paper a new control method of Electric Power Steering (EPS) system with Variable Gear Transmission System (VGTS) is proposed. The control purpose is to achieve the desired steering gear ratio and the desired power assist with good steering feel. The basic idea of controller design is to apply decoupling control to this system and to separately design controllers for two decoupled systems. The angle control system and the torque control system are designed for the decoupled systems. In the angle control system the PID control is used for the desired gear ratio. In the torque control system the PID control is used for the desired assist torque designed so as to achieve good steering feel. In order to evaluate steering feel the Lissajous curve between the steering torque and steering angle is used. The effectiveness of the proposed controller is verified experimentally.

  3. SPS Beam Steering for LHC Extraction

    CERN Document Server

    Gianfelice Wendt, E; Cornelis, K; Norderhaug Drosdal, L; Goddard, B; Kain, V; Meddahi, M; Papaphilippou, Y; Wenninger, J

    2014-01-01

    Beside producing beams for fixed target operation, the CERN Super Proton Synchrotron (SPS) accelerates beams for injection into the Large Hadron Collider (LHC). During the 2012-2013 run drifts of the extracted beam horizontal trajectories have been observed and lengthy optimizations in the transfer lines were performed to reduce particle losses. The observed trajectory drifts are consistent with the measured SPS orbit drifts at extraction. The feasibility of an automatic beam steering towards a “golden” orbit at the extraction septa, has been therefore investigated. The challenges and constraints related to the implementation of such a correction in the SPS are described. Simulation results are presented and a possible operational steering strategy is proposed. As the observed drift is mainly horizontal, the horizontal plane only will be considered.

  4. Boundaries can steer active Janus spheres

    Science.gov (United States)

    Das, Sambeeta; Garg, Astha; Campbell, Andrew I.; Howse, Jonathan; Sen, Ayusman; Velegol, Darrell; Golestanian, Ramin; Ebbens, Stephen J.

    2015-12-01

    The advent of autonomous self-propulsion has instigated research towards making colloidal machines that can deliver mechanical work in the form of transport, and other functions such as sensing and cleaning. While much progress has been made in the last 10 years on various mechanisms to generate self-propulsion, the ability to steer self-propelled colloidal devices has so far been much more limited. A critical barrier in increasing the impact of such motors is in directing their motion against the Brownian rotation, which randomizes particle orientations. In this context, here we report directed motion of a specific class of catalytic motors when moving in close proximity to solid surfaces. This is achieved through active quenching of their Brownian rotation by constraining it in a rotational well, caused not by equilibrium, but by hydrodynamic effects. We demonstrate how combining these geometric constraints can be utilized to steer these active colloids along arbitrary trajectories.

  5. SPS Beam Steering for LHC Extraction

    Energy Technology Data Exchange (ETDEWEB)

    Gianfelice-Wendt, Eliana [Fermilab; Bartosik, Hannes [CERN; Cornelis, Karel [CERN; Norderhaug Drøsdal, Lene [CERN; Goddard, Brennan [CERN; Kain, Verena [CERN; Meddahi, Malika [CERN; Papaphilippou, Yannis [CERN; Wenninger, Jorg [CERN

    2014-07-01

    The CERN Super Proton Synchrotron accelerates beams for the Large Hadron Collider to 450 GeV. In addition it produces beams for fixed target facilities which adds complexity to the SPS operation. During the run 2012-2013 drifts of the extracted beam trajectories have been observed and lengthy optimizations in the transfer lines were performed to reduce particle losses in the LHC. The observed trajectory drifts are consistent with the measured SPS orbit drifts at extraction. While extensive studies are going on to understand, and possibly suppress, the source of such SPS orbit drifts the feasibility of an automatic beam steering towards a “golden” orbit at the extraction septa, by means of the interlocked correctors, is also being investigated. The challenges and constraints related to the implementation of such a correction in the SPS are described. Simulation results are presented and a possible operational steering strategy is proposed.

  6. Indexing system for optical beam steering

    Science.gov (United States)

    Sullivan, Mark T.; Cannon, David M.; Debra, Daniel B.; Young, Jeffrey A.; Mansfield, Joseph A.; Carmichael, Roger E.; Lissol, Peter S.; Pryor, G. M.; Miklosy, Les G.; Lee, Jeffrey H.

    1990-01-01

    This paper describes the design and testing of an indexing system for optical-beam steering. The cryogenic beam-steering mechanism is a 360-degree rotation device capable of discrete, high-precision alignment positions. It uses low-precision components for its rough alignment and kinematic design to meet its stringent repeatability and stability requirements (of about 5 arcsec). The principal advantages of this design include a decoupling of the low-precision, large angular motion from the high-precision alignment, and a power-off alignment position that potentially extends the life or hold time of cryogenic systems. An alternate design, which takes advantage of these attributes while reducing overall motion, is also presented. Preliminary test results show the kinematic mount capable of sub-arc second repeatability.

  7. ACTIVE FRONT STEERING DURING BRAKING PROCESS

    Institute of Scientific and Technical Information of China (English)

    CHEN Deling; CHEN Li; YIN Chengliang; ZHANG Yong

    2008-01-01

    An active front steering (AFS) intervention control during braking for vehicle stability is presented. Based on the investigation of AFS mechanism, a simplified model of steering system is established and integrated with vehicle model. Then the AFS control on vehicle handling dynamics during braking is designed. Due to the difficulties associated with the sideslip angle measurement of vehicle, a state observer is designed to provide real time estimation. Thereafter, the controller with the feedback of both sideslip and yaw angle is implemented. To evaluate the system control, the proposed AFS controlled vehicle has been tested in the Hardware-in-the-loop-simulation (HILS) system and compared with that of conventional vehicle. Results show that AFS can improve vehicle lateral stability effectively without reducing the braking performance.

  8. Self-testing through EPR-steering

    Science.gov (United States)

    Šupić, Ivan; Hoban, Matty J.

    2016-07-01

    The verification of quantum devices is an important aspect of quantum information, especially with the emergence of more advanced experimental implementations of quantum computation and secure communication. Within this, the theory of device-independent robust self-testing via Bell tests has reached a level of maturity now that many quantum states and measurements can be verified without direct access to the quantum systems: interaction with the devices is solely classical. However, the requirements for this robust level of verification are daunting and require high levels of experimental accuracy. In this paper we discuss the possibility of self-testing where we only have direct access to one part of the quantum device. This motivates the study of self-testing via EPR-steering, an intermediate form of entanglement verification between full state tomography and Bell tests. Quantum non-locality implies EPR-steering so results in the former can apply in the latter, but we ask what advantages may be gleaned from the latter over the former given that one can do partial state tomography? We show that in the case of self-testing a maximally entangled two-qubit state, or ebit, EPR-steering allows for simpler analysis and better error tolerance than in the case of full device-independence. On the other hand, this improvement is only a constant improvement and (up to constants) is the best one can hope for. Finally, we indicate that the main advantage in self-testing based on EPR-steering could be in the case of self-testing multi-partite quantum states and measurements. For example, it may be easier to establish a tensor product structure for a particular party’s Hilbert space even if we do not have access to their part of the global quantum system.

  9. On the Feasibility of Dynamic Power Steering

    Energy Technology Data Exchange (ETDEWEB)

    Barker, Kevin J.; Kerbyson, Darren J.; Anger, Eric A.

    2014-11-16

    While high performance has always been the primary constraint behind large-scale system design, future systems will be built with increasing energy efficiency in mind. Mechanisms such as fine-grained power scaling and gating will provide tools to system-software and application developers to ensure the most efficient use of tightly constrained power budgets. Such approaches to-date have been focused on node level optimizations to impact overall system energy efficiency. In this work we introduce Dynamic Power Steering, in which power can be dynamically routed across a system to resources where it will be of most benefit and away from other resources to maintain a near-constant overall power budget. This, a higher level algorithmic approach to improving energy efficiency, considers the whole extent of a system being used by an application. It can be used for applications in which there is load imbalance that varies over its execution. Using two classes of applications, namely those that contain a wave front type processing, and a particle-in-cell, we quantify the benefit of Dynamic Power Steering for a variety of workload characteristics and derive some insight into the ways in which workload behavior affect Power Steering applicability.

  10. Oblique incidence effect on steering efficiency of liquid crystal polarization gratings used for optical phased array beam steering amplification

    Science.gov (United States)

    Xiangjie, Zhao; Jiazhu, Duan; Dayong, Zhang; Cangli, Liu; Yongquan, Luo

    2016-07-01

    A liquid crystal polarization grating (LCPG) is proposed that amplifies the steering angle of a liquid crystal optical phased array for non-mechanical beam steering, taking advantage of its high steering efficiency under normal incidence. However, oblique incidence may play an important role in the overall steering efficiency. The effect of oblique incidence on steering efficiency of a LCPG was analyzed by numerically solving the extended Jones matrix and considering propagation crosstalk. The results indicate that the outgoing laser beam is amplitude-modulated under the effect of oblique incidence and behaves as a sinusoidal-modulated amplitude grating, which diffracts certain energies to non-blazed orders. Over-oblique incidence may even eliminate the steering effect of the incident beam. The modulation depth of the induced amplitude grating was found to be proportional to the product of sinusoidal value of oblique incidence angle and the LC layer thickness, and inversely proportional to the periodic pitch length of the LCPG. Both in-plane incidence and out-of-plane incidence behave similarly to influence the steering efficiency. Finally, the overall steering efficiency for cascaded LCPGs was analyzed and a difference of up to 11 % steering efficiency can be induced between different LCPG configurations, even without considering the over-oblique incidence effect. Both the modulation depth and final steering efficiency can be optimized by varying the LC birefringence and layer thickness.

  11. Oblique incidence effect on steering efficiency of liquid crystal polarization gratings used for optical phased array beam steering amplification

    Science.gov (United States)

    Xiangjie, Zhao; Jiazhu, Duan; Dayong, Zhang; Cangli, Liu; Yongquan, Luo

    2016-10-01

    A liquid crystal polarization grating (LCPG) is proposed that amplifies the steering angle of a liquid crystal optical phased array for non-mechanical beam steering, taking advantage of its high steering efficiency under normal incidence. However, oblique incidence may play an important role in the overall steering efficiency. The effect of oblique incidence on steering efficiency of a LCPG was analyzed by numerically solving the extended Jones matrix and considering propagation crosstalk. The results indicate that the outgoing laser beam is amplitude-modulated under the effect of oblique incidence and behaves as a sinusoidal-modulated amplitude grating, which diffracts certain energies to non-blazed orders. Over-oblique incidence may even eliminate the steering effect of the incident beam. The modulation depth of the induced amplitude grating was found to be proportional to the product of sinusoidal value of oblique incidence angle and the LC layer thickness, and inversely proportional to the periodic pitch length of the LCPG. Both in-plane incidence and out-of-plane incidence behave similarly to influence the steering efficiency. Finally, the overall steering efficiency for cascaded LCPGs was analyzed and a difference of up to 11 % steering efficiency can be induced between different LCPG configurations, even without considering the over-oblique incidence effect. Both the modulation depth and final steering efficiency can be optimized by varying the LC birefringence and layer thickness.

  12. Thiol Redox Transitions in Cell Signaling: a Lesson from N-Acetylcysteine

    Directory of Open Access Journals (Sweden)

    Tiziana Parasassi

    2010-01-01

    Full Text Available The functional status of cells is under the control of external stimuli affecting the function of critical proteins and eventually gene expression. Signal sensing and transduction by messengers to specific effectors operate by post-translational modification of proteins, among which thiol redox switches play a fundamental role that is just beginning to be understood. The maintenance of the redox status is, indeed, crucial for cellular homeostasis and its dysregulation towards a more oxidized intracellular environment is associated with aberrant proliferation, ultimately related to diseases such as cancer, cardiovascular disease, and diabetes. Redox transitions occur in sensitive cysteine residues of regulatory proteins relevant to signaling, their evolution to metastable disulfides accounting for the functional redox switch. N-acetylcysteine (NAC is a thiol-containing compound that is able to interfere with redox transitions of thiols and, thus, in principle, able to modulate redox signaling. We here review the redox chemistry of NAC, then screen possible mechanisms to explain the effects observed in NAC-treated normal and cancer cells; such effects involve a modification of global gene expression, thus of functions and morphology, with a leitmotif of a switch from proliferation to terminal differentiation. The regulation of thiol redox transitions in cell signaling is, therefore, proposed as a new tool, holding promise not only for a deeper explanation of mechanisms, but indeed for innovative pharmacological interventions.

  13. Comparison of manual steering and steering via joystick of a flexible rhino endoscope.

    Science.gov (United States)

    Eckl, R; Gumprecht, J J; Strauss, G; Hofer, M; Dietz, A; Lueth, T C

    2010-01-01

    Flexible endoscopes are used in ENT surgery for examination tasks in cases wherever rigid endoscopes are unsuitable to reach certain positions in the nasal cavity. Until today they are steered by hand and no robotized system has been put into clinical practice. One qualification a robot manipulator system has to fulfill to be accepted is not to create new disadvantages compared to the conventional method in surgery. An important factor is the time needed to steer the new system compared to the time needed to steer the conventional system. In this article a robot manipulator system and an experiment are presented to compare the particular times test persons need to perform a certain task. This approach offers the possibility to benchmark the developed robot manipulator system and future systems for flexible rhino endoscopes.

  14. Redox Properties of Free Radicals.

    Science.gov (United States)

    Neta, P.

    1981-01-01

    Describes pulse radiolysis as a useful means in studing one-electron redox potentials. This method allows the production of radicals and the determination of their concentration and rates of reaction. (CS)

  15. Multipartite Gaussian steering: monogamy constraints and cryptographical applications

    CERN Document Server

    Xiang, Yu; Adesso, Gerardo; He, Qiongyi

    2016-01-01

    We derive laws for the distribution of quantum steering among different parties in multipartite Gaussian states under Gaussian measurements. We prove that a monogamy relation akin to the generalized Coffman-Kundu-Wootters inequality holds quantitatively for a recently introduced measure of Gaussian steering. We then define the residual Gaussian steering, stemming from the monogamy inequality, as an indicator of collective steering-type correlations. For pure three-mode Gaussian states, the residual acts a quantifier of genuine multipartite steering, and is interpreted operationally in terms of the guaranteed key rate in the task of secure quantum secret sharing. Optimal resource states for the latter protocol are identified, and their possible experimental implementation discussed. Our results pin down the role of multipartite steering for quantum communication.

  16. Fault-tolerant Actuator System for Electrical Steering of Vehicles

    DEFF Research Database (Denmark)

    Sørensen, Jesper Sandberg; Blanke, Mogens

    2006-01-01

    Being critical to the safety of vehicles, the steering system is required to maintain the vehicles ability to steer until it is brought to halt, should a fault occur. With electrical steering becoming a cost-effective candidate for electrical powered vehicles, a fault-tolerant architecture...... is needed that meets this requirement. This paper studies the fault-tolerance properties of an electrical steering system. It presents a fault-tolerant architecture where a dedicated AC motor design used in conjunction with cheap voltage measurements can ensure detection of all relevant faults...... in the steering system. The paper shows how active control reconfiguration can accommodate all critical faults. The fault-tolerant abilities of the steering system are demonstrated on the hardware of a warehouse truck....

  17. Gaussian quantum steering and its asymmetry in curved spacetime

    CERN Document Server

    Wang, Jieci; Jing, Jiliang; Fan, Heng

    2015-01-01

    We study Gaussian quantum steering and its asymmetry in the background of a Schwarzschild black hole. We present a Gaussian channel description of quantum state evolution under the influence of Hawking radiation. We find that thermal noise introduced by Hawking effect will destroy the steerability between an inertial observer Alice and an accelerated observer Bob who hovers outside an event horizon, while it generates steerability between Bob and a hypothetical observer Anti-Bob inside the event horizon. Besides, unlike entanglement behaviors in curved spacetime, here the steering from Alice to Bob suffers from a ``sudden death" and the steering from Anti-Bob to Bob appears a ``sudden birth" with the increasing of Hawking temperature. We also find that the Gaussian steering is always asymmetric and the maximum steering asymmetry can \\emph{ exceed} $\\ln 2$ in curved spacetime, which is quite different from the flat spacetime case [Phys. Rev. Lett. 114, 060403 (2015)] where the steering asymmetry can \\emph{neve...

  18. Bifunctional redox flow battery

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Y.H. [Research Institute of Chemical Defense, Beijing 100083 (China)], E-mail: wen_yuehua@126.com; Cheng, J. [Research Institute of Chemical Defense, Beijing 100083 (China); Beijing Science and Technology University, Beijing 100083 (China); Xun, Y. [Research Institute of Chemical Defense, Beijing 100083 (China); Ma, P.H. [Full Cell R and D Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023 (China); Yang, Y.S. [Research Institute of Chemical Defense, Beijing 100083 (China); Beijing Science and Technology University, Beijing 100083 (China)

    2008-08-20

    A new bifunctional redox flow battery (BRFB) system, V(III)/V(II)-L-cystine(O{sub 2}), was systematically investigated by using different separators. It is shown that during charge, water transfer is significantly restricted with increasing the concentration of HBr when the Nafion 115 cation exchange membrane is employed. The same result can be obtained when the gas diffusion layer (GDL) hot-pressed separator is used. The organic electro-synthesis is directly correlated with the crossover of vanadium. When employing the anion exchange membrane, the electro-synthesis efficiency is over 96% due to a minimal crossover of vanadium. When the GDL hot-pressed separator is applied, the crossover of vanadium and water transfer are noticeably prevented and the electro-synthesis efficiency of over 99% is obtained. Those impurities such as vanadium ions and bromine can be eliminated through the purification of organic electro-synthesized products. The purified product is identified to be L-cysteic acid by IR spectrum. The BRFB shows a favorable discharge performance at a current density of 20 mA cm{sup -2}. Best discharge performance is achieved by using the GDL hot-pressed separator. The coulombic efficiency of 87% and energy efficiency of about 58% can be obtained. The cause of major energy losses is mainly associated with the cross-contamination of anodic and cathodic active electrolytes.

  19. Thioredoxin/Txnip: Redoxisome, As a Redox Switch for the Pathogenesis of Diseases

    Directory of Open Access Journals (Sweden)

    Eiji eYoshihara

    2014-01-01

    Full Text Available During the past few decades, it has been widely recognized that reducing-oxidizing (Redox responses occurring at the intra- and extra-cellular levels are one of most important biological phenomena and dysregulated redox responses are involved in the initiation and progression of multiple diseases. Thioredoxin 1 (Trx1 and Thioredoxin 2 (Trx2, mainly located in the cytoplasm and mitochondria, respectively, are ubiquitously expressed in variety of cells and control cellular reactive oxygen species (ROS by reducing the disulfides into thiol groups. Thioredoxin interacting protein (Txnip/TBP-2/VDUP1 directly binds to Trx1 & Trx2 (Trx and inhibit the reducing activity of Trx through their disulfide exchange. Recent studies have revealed that Trx1 and Txnip are involved in some critical redox-dependent signal pathways including NLRP3 inflammasome activation in a redox-dependent manner. Therefore, Trx/Txnip, a redox-sensitive signaling complex is a regulator of cellular redox status and has emerged as a key component in the link between redox-regulation and the pathogenesis of diseases. Here, we review the novel functional concept of the redox-related protein complex, named Redoxisome, consisting of Trx/Txnip, as a critical regulator for intra- and extra-cellular redox signaling, involved in the pathogenesis of various diseases such as cancer, autoimmune disease, and diabetes.

  20. Redox regulation of protein damage in plasma

    Directory of Open Access Journals (Sweden)

    Helen R. Griffiths

    2014-01-01

    In this review, we focus on redox regulatory control of those enzymes and processes which control protein maturation during synthesis, produce reactive species, repair and remove damaged plasma proteins. We have highlighted the potential for alterations in the extracellular redox compartment to regulate intracellular redox state and, conversely, for intracellular oxidative stress to alter the cellular secretome and composition of extracellular vesicles. Through secreted, redox-active regulatory molecules, changes in redox state may be transmitted to distant sites.

  1. Multi-axle dynamic steering system of truck-howitzer

    Institute of Scientific and Technical Information of China (English)

    Yanliang LI; Xiuhua GAO; Chunqiu ZHANG; Yubo SUN

    2008-01-01

    A two-degree-of-freedom (2-DOF) steering model of multi-axle vehicle was established. The steering center position, the relationship between the steering angle and the vehicle velocity, and the minimum turn radius were deduced on the basis of the proportional control with a zero sideslip angle. Results indicate that the system stability is decided by the vehicle barycenter position and the lateral stiffness of a tire. Under this control, the steady value of the lateral acceleration is obviously diminished and the yaw angular velocity changes little under any vehicle velocity. The system rapidly responds, the vehicle smoothly steers, and its handling stability is prominently improved.

  2. Analysis of Vehicle Steering and Driving Bifurcation Characteristics

    Directory of Open Access Journals (Sweden)

    Xianbin Wang

    2015-01-01

    Full Text Available The typical method of vehicle steering bifurcation analysis is based on the nonlinear autonomous vehicle model deriving from the classic two degrees of freedom (2DOF linear vehicle model. This method usually neglects the driving effect on steering bifurcation characteristics. However, in the steering and driving combined conditions, the tyre under different driving conditions can provide different lateral force. The steering bifurcation mechanism without the driving effect is not able to fully reveal the vehicle steering and driving bifurcation characteristics. Aiming at the aforementioned problem, this paper analyzed the vehicle steering and driving bifurcation characteristics with the consideration of driving effect. Based on the 5DOF vehicle system dynamics model with the consideration of driving effect, the 7DOF autonomous system model was established. The vehicle steering and driving bifurcation dynamic characteristics were analyzed with different driving mode and driving torque. Taking the front-wheel-drive system as an example, the dynamic evolution process of steering and driving bifurcation was analyzed by phase space, system state variables, power spectral density, and Lyapunov index. The numerical recognition results of chaos were also provided. The research results show that the driving mode and driving torque have the obvious effect on steering and driving bifurcation characteristics.

  3. Einstein-Podolsky-Rosen steering and quantum steering ellipsoids: Optimal two-qubit states and projective measurements

    Science.gov (United States)

    McCloskey, R.; Ferraro, A.; Paternostro, M.

    2017-01-01

    We identify the families of states that maximize some recently proposed quantifiers of Einstein-Podolsky-Rosen (EPR) steering and the volume of the quantum steering ellipsoid (QSE). The optimal measurements which maximize genuine EPR steering measures are discussed and we develop a way to find them using the QSE. We thus explore the links between genuine EPR steering and the QSE and introduce states that can be the most useful for one-sided device-independent quantum cryptography for a given amount of noise.

  4. Study on control schemes of flexible steering system of a multi-axle all-wheel-steering robot

    Directory of Open Access Journals (Sweden)

    Pingxia Zhang

    2016-05-01

    Full Text Available It is well known that a multi-axle wheeled robot possesses larger load capability and also higher drive performance. However, its steering flexibility is degraded due to the large number of wheels. In order to solve this problem, in this article, we proposed three control schemes based on the center of rotation or the steering angles of both the first- and last-axle wheels. To release these control schemes, steering mode selection and also the left wheel’s steering angle in a specific axle are added approaching a practical application. Thereafter, the remaining wheels’ steering angles can be calculated with the Ackerman steering theorem. In order to verify the control effects, a five-axle all-wheel-steering wheeled robot has been developed with the Bluetooth wireless monitor system. Based on the newly designed robot, validation experiments are carried out, such as lateral movement, situ rotation, and multi-mode steering within a narrow space. The results indicate that the proposed design in this article can ensure a more flexible and faster movement within a narrow space. It shows large potential in obstacle avoidance compared with the conventional partial-wheel steering mode.

  5. Predicting water intake by yearling feedlot steers.

    Science.gov (United States)

    Sexson, J L; Wagner, J J; Engle, T E; Eickhoff, J

    2012-06-01

    Data from 4 separate beef cattle feedlot experiments, which were conducted at the Southeast Colorado Research Center (SECRC) in Lamar, CO, in 2001, 2003, 2004, and 2007, were utilized in a retrospective longitudinal study investigating possible relationships between daily water consumption (WC), DMI, and weather variables. The data set consisted of 8,209 records from 2001, 2003, 2004, and 2007, with pen based daily WC (L•animal(-1)) and DMI measurements and calculated daily steer BW from April to October in each year. Daily weather data were obtained from the weather station located at Lamar Municipal Airport located approximately 1.9 km from SECRC. Data collected consisted of daily high, low, and mean temperature; high, low, and mean humidity; high, low, and mean sea level pressure; mean wind speed; total precipitation; and average daily wind direction (cosine of radians from due north). Univariate analysis demonstrated that the continuous variables of BW, humidity, and sea level pressure were negatively related (P high temperature squared, high humidity squared, low temperature, low temperature squared, low humidity, average sea level pressure, average wind speed, average daily BW, high sea level pressure, low sea level pressure, high humidity, and low humidity. The generalized R(2) of the parsimonious multivariate model was 0.32. These results indicate that BW and numerous weather factors are related to WC by yearling feedlot steers. Dry matter intake had minimal impact on WC for yearling feedlot steers consuming steam-flaked corn-based high concentrate diets from mid-spring to early fall.

  6. Stress indicators in steers at slaughtering

    Directory of Open Access Journals (Sweden)

    A. Zarrilli

    2010-04-01

    Full Text Available This work aimed to assess the blood modifications of some slaughtering-linked stress hormones in cattle subject to butcher standardized procedures. The blood samples of 20 Limousine 12-13 months old steers have been collected before slaughtering, during lairage, and after stunning by captive bolt gun, during exsanguination. The plasma level of epinephrine, norepinephrine, cortisol and beta-endorphin have been assayed by EIA. The data indicate that catecholamines, cortisol and beta-endorphin did not significantly increase after stunning in these animals.

  7. Redox Homeostasis in Pancreatic Cells

    Directory of Open Access Journals (Sweden)

    Petr Ježek

    2012-01-01

    Full Text Available We reviewed mechanisms that determine reactive oxygen species (redox homeostasis, redox information signaling and metabolic/regulatory function of autocrine insulin signaling in pancreatic β cells, and consequences of oxidative stress and dysregulation of redox/information signaling for their dysfunction. We emphasize the role of mitochondrion in β cell molecular physiology and pathology, including the antioxidant role of mitochondrial uncoupling protein UCP2. Since in pancreatic β cells pyruvate cannot be easily diverted towards lactate dehydrogenase for lactate formation, the respiration and oxidative phosphorylation intensity are governed by the availability of glucose, leading to a certain ATP/ADP ratio, whereas in other cell types, cell demand dictates respiration/metabolism rates. Moreover, we examine the possibility that type 2 diabetes mellitus might be considered as an inevitable result of progressive self-accelerating oxidative stress and concomitantly dysregulated information signaling in peripheral tissues as well as in pancreatic β cells. It is because the redox signaling is inherent to the insulin receptor signaling mechanism and its impairment leads to the oxidative and nitrosative stress. Also emerging concepts, admiting participation of redox signaling even in glucose sensing and insulin release in pancreatic β cells, fit in this view. For example, NADPH has been firmly established to be a modulator of glucose-stimulated insulin release.

  8. Redox electrode materials for supercapatteries

    Science.gov (United States)

    Yu, Linpo; Chen, George Z.

    2016-09-01

    Redox electrode materials, including transition metal oxides and electronically conducting polymers, are capable of faradaic charge transfer reactions, and play important roles in most electrochemical energy storage devices, such as supercapacitor, battery and supercapattery. Batteries are often based on redox materials with low power capability and safety concerns in some cases. Supercapacitors, particularly those based on redox inactive materials, e.g. activated carbon, can offer high power output, but have relatively low energy capacity. Combining the merits of supercapacitor and battery into a hybrid, the supercapattery can possess energy as much as the battery and output a power almost as high as the supercapacitor. Redox electrode materials are essential in the supercapattery design. However, it is hard to utilise these materials easily because of their intrinsic characteristics, such as the low conductivity of metal oxides and the poor mechanical strength of conducting polymers. This article offers a brief introduction of redox electrode materials, the basics of supercapattery and its relationship with pseudocapacitors, and reviews selectively some recent progresses in the relevant research and development.

  9. Redox regulation of mitochondrial biogenesis.

    Science.gov (United States)

    Piantadosi, Claude A; Suliman, Hagir B

    2012-12-01

    The cell renews, adapts, or expands its mitochondrial population during episodes of cell damage or periods of intensified energy demand by the induction of mitochondrial biogenesis. This bigenomic program is modulated by redox-sensitive signals that respond to physiological nitric oxide (NO), carbon monoxide (CO), and mitochondrial reactive oxygen species production. This review summarizes our current ideas about the pathways involved in the activation of mitochondrial biogenesis by the physiological gases leading to changes in the redox milieu of the cell, with an emphasis on the responses to oxidative stress and inflammation. The cell's energy supply is protected from conditions that damage mitochondria by an inducible transcriptional program of mitochondrial biogenesis that operates in large part through redox signals involving the nitric oxide synthase and the heme oxygenase-1/CO systems. These redox events stimulate the coordinated activities of several multifunctional transcription factors and coactivators also involved in the elimination of defective mitochondria and the expression of counterinflammatory and antioxidant genes, such as IL10 and SOD2, as part of a unified damage-control network. The redox-regulated mechanisms of mitochondrial biogenesis schematically outlined in the graphical abstract link mitochondrial quality control to an enhanced capacity to support the cell's metabolic needs while improving its resistance to metabolic failure and avoidance of cell death during periods of oxidative stress.

  10. 3D computational steering with parametrized geometric objects

    NARCIS (Netherlands)

    Mulder, J.D.; Wijk, J.J. van

    1996-01-01

    Computational Steering is the ultimate goal of interactive simulation: researchers change parameters of their simulation and immediately receive feedback on the effect. We present a general and flexible graphics tool that is part of an environment for Computational Steering developed at CWI. It enab

  11. Gaussian quantum steering and its asymmetry in curved spacetime

    Science.gov (United States)

    Wang, Jieci; Cao, Haixin; Jing, Jiliang; Fan, Heng

    2016-06-01

    We study Gaussian quantum steering and its asymmetry in the background of a Schwarzschild black hole. We present a Gaussian channel description of quantum state evolution under the influence of Hawking radiation. We find that thermal noise introduced by the Hawking effect will destroy the steerability between an inertial observer Alice and an accelerated observer Bob who hovers outside the event horizon, while it generates steerability between Bob and a hypothetical observer anti-Bob inside the event horizon. Unlike entanglement behaviors in curved spacetime, here the steering from Alice to Bob suffers from a "sudden death" and the steering from anti-Bob to Bob experiences a "sudden birth" with increasing Hawking temperature. We also find that the Gaussian steering is always asymmetric and the maximum steering asymmetry cannot exceed ln 2 , which means the state never evolves to an extremal asymmetry state. Furthermore, we obtain the parameter settings that maximize steering asymmetry and find that (i) s =arccosh cosh/2r 1 -sinh2r is the critical point of steering asymmetry and (ii) the attainment of maximal steering asymmetry indicates the transition between one-way steerability and both-way steerability for the two-mode Gaussian state under the influence of Hawking radiation.

  12. Robotic needle steering: design, modeling, planning, and image guidance

    NARCIS (Netherlands)

    Cowan, Noah J.; Goldberg, Ken; Chirikjian, Gregory S.; Fichtinger, Gabor; Alterovitz, Ron; Reed, Kyle B.; Kallem, Vinutha; Park, Wooram; Misra, Sarthak; Okamura, Allison M.; Rosen, Jacob; Hannaford, Blake; Satava, Richard M.

    2010-01-01

    This chapter describes how advances in needle design, modeling, planning, and image guidance make it possible to steer flexible needles from outside the body to reach specified anatomical targets not accessible using traditional needle insertion methods. Steering can be achieved using a variety of m

  13. The impact of force feedback level on steering performance

    NARCIS (Netherlands)

    Anand, S.; Terken, J.; Hogema, J.H.

    2013-01-01

    Steer-by-wire systems provide designers the ability to customize and personalize force feedback on the steering wheel, based on individual preferences. Earlier studies using subjective responses have shown that there are individual differences in preferences for force feedback. It has also been foun

  14. The effect of varying path properties in path steering tasks

    NARCIS (Netherlands)

    Liu, L.; Liere, R. van

    2010-01-01

    Path steering is a primitive 3D interaction task that requires the user to navigate through a path of a given length and width. In a previous paper, we have conducted controlled experiments in which users operated a pen input device to steer a cursor through a 3D path subject to fixed path propertie

  15. Mouse redox histology using genetically encoded probes.

    Science.gov (United States)

    Fujikawa, Yuuta; Roma, Leticia P; Sobotta, Mirko C; Rose, Adam J; Diaz, Mauricio Berriel; Locatelli, Giuseppe; Breckwoldt, Michael O; Misgeld, Thomas; Kerschensteiner, Martin; Herzig, Stephan; Müller-Decker, Karin; Dick, Tobias P

    2016-03-15

    Mapping the in vivo distribution of endogenous oxidants in animal tissues is of substantial biomedical interest. Numerous health-related factors, including diet, physical activity, infection, aging, toxins, or pharmacological intervention, may cause redox changes. Tools are needed to pinpoint redox state changes to particular organs, tissues, cell types, and subcellular organelles. We describe a procedure that preserves the in vivo redox state of genetically encoded redox biosensors within histological tissue sections, thus providing "redox maps" for any tissue and comparison of interest. We demonstrate the utility of the technique by visualizing endogenous redox differences and changes in the context of tumor growth, inflammation, embryonic development, and nutrient starvation.

  16. Internal models direct dragonfly interception steering.

    Science.gov (United States)

    Mischiati, Matteo; Lin, Huai-Ti; Herold, Paul; Imler, Elliot; Olberg, Robert; Leonardo, Anthony

    2015-01-15

    Sensorimotor control in vertebrates relies on internal models. When extending an arm to reach for an object, the brain uses predictive models of both limb dynamics and target properties. Whether invertebrates use such models remains unclear. Here we examine to what extent prey interception by dragonflies (Plathemis lydia), a behaviour analogous to targeted reaching, requires internal models. By simultaneously tracking the position and orientation of a dragonfly's head and body during flight, we provide evidence that interception steering is driven by forward and inverse models of dragonfly body dynamics and by models of prey motion. Predictive rotations of the dragonfly's head continuously track the prey's angular position. The head-body angles established by prey tracking appear to guide systematic rotations of the dragonfly's body to align it with the prey's flight path. Model-driven control thus underlies the bulk of interception steering manoeuvres, while vision is used for reactions to unexpected prey movements. These findings illuminate the computational sophistication with which insects construct behaviour.

  17. Impact of APE1/Ref-1 redox inhibition on pancreatic tumor growth.

    Science.gov (United States)

    Fishel, Melissa L; Jiang, Yanlin; Rajeshkumar, N V; Scandura, Glenda; Sinn, Anthony L; He, Ying; Shen, Changyu; Jones, David R; Pollok, Karen E; Ivan, Mircea; Maitra, Anirban; Kelley, Mark R

    2011-09-01

    Pancreatic cancer is especially a deadly form of cancer with a survival rate less than 2%. Pancreatic cancers respond poorly to existing chemotherapeutic agents and radiation, and progress for the treatment of pancreatic cancer remains elusive. To address this unmet medical need, a better understanding of critical pathways and molecular mechanisms involved in pancreatic tumor development, progression, and resistance to traditional therapy is therefore critical. Reduction-oxidation (redox) signaling systems are emerging as important targets in pancreatic cancer. AP endonuclease1/Redox effector factor 1 (APE1/Ref-1) is upregulated in human pancreatic cancer cells and modulation of its redox activity blocks the proliferation and migration of pancreatic cancer cells and pancreatic cancer-associated endothelial cells in vitro. Modulation of APE1/Ref-1 using a specific inhibitor of APE1/Ref-1's redox function, E3330, leads to a decrease in transcription factor activity for NFκB, AP-1, and HIF1α in vitro. This study aims to further establish the redox signaling protein APE1/Ref-1 as a molecular target in pancreatic cancer. Here, we show that inhibition of APE1/Ref-1 via E3330 results in tumor growth inhibition in cell lines and pancreatic cancer xenograft models in mice. Pharmacokinetic studies also show that E3330 attains more than10 μmol/L blood concentrations and is detectable in tumor xenografts. Through inhibition of APE1/Ref-1, the activity of NFκB, AP-1, and HIF1α that are key transcriptional regulators involved in survival, invasion, and metastasis is blocked. These data indicate that E3330, inhibitor of APE1/Ref-1, has potential in pancreatic cancer and clinical investigation of APE1/Ref-1 molecular target is warranted.

  18. Conclusive quantum steering with superconducting transition edge sensors

    CERN Document Server

    Smith, Devin H; de Almeida, Marcelo; Branciard, Cyril; Fedrizzi, Alessandro; Weinhold, Till J; Lita, Adriana; Calkins, Brice; Gerrits, Thomas; Nam, Sae Woo; White, Andrew G

    2011-01-01

    Quantum steering allows two parties to verify shared entanglement even if one measurement device is untrusted. A conclusive demonstration of steering through the violation of a steering inequality is of considerable fundamental interest and opens up applications in quantum communication. To date all experimental tests with single photon states have relied on post-selection, allowing untrusted devices to cheat by hiding unfavorable events in losses. Here we close this "detection loophole" by combining a highly efficient source of entangled photon pairs with superconducting transition edge sensors. We achieve an unprecedented $\\sim$62% conditional detection efficiency of entangled photons and violate a steering inequality with the minimal number of measurement settings by 48 standard deviations. Our results provide a clear path to practical applications of steering and to a photonic loophole-free Bell test.

  19. Sidelobe Suppression with Null Steering by Independent Weight Control

    Directory of Open Access Journals (Sweden)

    Zafar-Ullah Khan

    2015-01-01

    Full Text Available A uniform linear array of n antenna elements can steer up to n-1 nulls. In situations where less than n-1 nulls are required to be steered, the existing algorithms have no criterion to utilize the remaining weights for sidelobe suppression. This work combines sidelobe suppression capability with null steering by independent weight control. For this purpose, the array factor is transformed as the product of two polynomials. One of the polynomials is used for null steering by independent weight control, while the second one is for sidelobe suppression whose coefficients or weights are determined by using convex optimization. Finally, a new structure is proposed to incorporate the product of two polynomials such that sidelobe suppression weights are decoupled from those of null steering weights. Simulation results validate the effectiveness of the proposed scheme.

  20. Experimental Study on Antivibration Control of Electrical Power Steering Systems

    Directory of Open Access Journals (Sweden)

    Zhaojian Wang

    2014-01-01

    Full Text Available We focus on the antivibration controller design problem for electrical power steering (EPS systems. The EPS system has significant advantages over the traditional hydraulic steering system. However, the improper motor controller design would lead to the steering wheel vibration. Therefore, it is necessary to investigate the antivibration control strategy. For the implementation study, we also present the motor driver design and the software design which is used to monitor the sensors and the control signal. Based on the investigation on the regular assistant algorithm, we summarize the difficulties and problems encountered by the regular algorithm. After that, in order to improve the performance of antivibration and the human-like steering feeling, we propose a new assistant strategy for the EPS. The experiment results of the bench test illustrate the effectiveness and flexibility of the proposed control strategy. Compared with the regular controller, the proposed antivibration control reduces the vibration of the steering wheel a lot.

  1. Redox Couples with Unequal Diffusion Coefficients: Effect on Redox Cycling

    NARCIS (Netherlands)

    Mampallil Augustine, Dileep; Mathwig, Klaus; Kang, Shuo; Lemay, Serge G.

    2013-01-01

    Redox cycling between two electrodes separated by a narrow gap allows dramatic amplification of the faradaic current. Unlike conventional electrochemistry at a single electrode, however, the mass-transport-limited current is controlled by the diffusion coefficient of both the reduced and oxidized fo

  2. Mitochondrially targeted fluorescent redox sensors.

    Science.gov (United States)

    Yang, Kylie; Kolanowski, Jacek L; New, Elizabeth J

    2017-04-06

    The balance of oxidants and antioxidants within the cell is crucial for maintaining health, and regulating physiological processes such as signalling. Consequently, imbalances between oxidants and antioxidants are now understood to lead to oxidative stress, a physiological feature that underlies many diseases. These processes have spurred the field of chemical biology to develop a plethora of sensors, both small-molecule and fluorescent protein-based, for the detection of specific oxidizing species and general redox balances within cells. The mitochondrion, in particular, is the site of many vital redox reactions. There is therefore a need to target redox sensors to this particular organelle. It has been well established that targeting mitochondria can be achieved by the use of a lipophilic cation-targeting group, or by utilizing natural peptidic mitochondrial localization sequences. Here, we review how these two approaches have been used by a number of researchers to develop mitochondrially localized fluorescent redox sensors that are already proving useful in providing insights into the roles of reactive oxygen species in the mitochondria.

  3. Beam Steering Mechanism (BSM) Lessons Learned

    Science.gov (United States)

    Blumenstock, Kenneth A.; Cramer, Alexander K.; Gostin, Alan B.; Hakun, Claef F.; Haney, Paul G.; Hinkle, Matthew R.; Lee, Kenneth Y.; Lugo, Carlos F.; Matuszeski, Adam J.; Morell, Armando; Armani, Nerses V.; Bonafede, Joseph; Jackson, Molly I.; Steigner, Peter J.; Stromsdorfer, Juan J.

    2016-01-01

    This paper describes the design, testing, and lessons learned during the development of the Advanced Topographic Laser Altimeter System (ATLAS) Beam Steering Mechanism (BSM). The BSM is a 2 degree-of-freedom tip-tilt mechanism for the purpose of pointing a flat mirror to tightly control the co-alignment of the transmitted laser and the receiver telescope of the ATLAS instrument. High resolution needs of the mission resulted in sub-arcsecond pointing and knowledge requirements, which have been met. Development of methodology to verify performance was a significant effortadvancement. The BSM will fly as part of the Ice, Cloud, and Elevation Satellite 2 Mission (ICESat 2), which is scheduled to be launched in 2017. The ICESat 2 primary mission is to map the earths surface topography for the determination of seasonal changes of ice sheet thickness as well as vegetation canopy thickness.

  4. ATLAS Beam Steering Mechanism (BSM) Lessons Learned

    Science.gov (United States)

    Blumenstock, Kenneth A.; Cramer, Alexander K.; Gosten, Alan B.; Hakun, Claef F.; Haney, Paul G.; Hinkle, Matthew R.; Lee, Kenneth Y.; Lugo, Carlos F.; Matuszeski, Adam J.; Morell, Armando; Armani, Nerses V.; Bonafede, Joseph; Jackson, Molly I.; Steigner, Peter J.; Stromsdorfer, Juan J.

    2016-01-01

    This paper describes the design, testing, and lessons learned during the development of the Advanced Topographic Laser Altimeter System (ATLAS) Beam Steering Mechanism (BSM). The BSM is a 2 degree-of-freedom tip-tilt mechanism for the purpose of pointing a flat mirror to tightly control the co-alignment of the transmitted laser and the receiver telescope of the ATLAS instrument. The high resolution needs of the mission resulted in sub-arcsecond pointing and knowledge requirements, which have been met. Development of the methodology to verify performance required significant effort. The BSM will fly as part of the Ice, Cloud, and Elevation Satellite II Mission (ICESat II), which is scheduled to be launched in 2017. The ICESat II primary mission is to map the Earth's surface topography for the determination of seasonal changes of ice sheet thickness and vegetation canopy thickness to establish long-term trends.

  5. ATLAS Beam Steering Mechanism Lessons Learned

    Science.gov (United States)

    Blumenstock, Kenneth A.; Cramer, Alexander K.; Gostin, Alan B.; Hakun, Claef F.; Haney, Paul G.; Hinkle, Matthew R.; Lee, Kenneth Y.; Lugo, Carlos F.; Matuszeski, Adam J.; Morrell, Armando; Armani, Nerses V.; Bonafede, Joseph; Jackson, Molly I.; Steigner, Peter J.; Stromsdorfer, Juan J.

    2016-01-01

    This paper describes the design, testing, and lessons learned during the development of the Advanced Topographic Laser Altimeter System (ATLAS) Beam Steering Mechanism (BSM). The BSM is a 2 degree-of-freedom tip-tilt mechanism for the purpose of pointing a flat mirror to tightly control the co-alignment of the transmitted laser and the receiver telescope of the ATLAS instrument. The high resolution needs of the mission resulted in sub-arcsecond pointing and knowledge requirements, which have been met. Development of the methodology to verify performance required significant effort. The BSM will fly as part of the Ice, Cloud, and Elevation Satellite II Mission (ICESat II), which is scheduled to be launched in 2017. The ICESat II primary mission is to map the earth's surface topography for the determination of seasonal changes of ice sheet thickness and vegetation canopy thickness to establish long-term trends.

  6. Phase shifter for antenna beam steering

    Science.gov (United States)

    Jindal, Ravi; Razban, Tchanguiz

    2016-03-01

    Wide band Array Antenna operates in Ku-band (10.7-12.7 GHz) frequency composed of N×N radiating elements. This antenna aims at the reception of television satellite signals. The goal of this research is to provide better possibility of electronic beam control instead of manual or mechanical control, and design compact and low cost phase shifters to be inserted in the feeding network of this antenna. The electronic control of the phase shifter will allow the control of beam steering. The emphasis of this project will be done at the beginning on the design of a good phase shifter in Ku band. The aim of this research is to define, simulate, release and measure a continuous phase shifter. Better reflection loss, low transmission loss, low Cost of array antennas, large range of phase-shifter, phase flatness and bandwidth will be achieved by providing better gain.

  7. Quantum steering: a review with focus on semidefinite programming

    Science.gov (United States)

    Cavalcanti, D.; Skrzypczyk, P.

    2017-02-01

    Quantum steering refers to the non-classical correlations that can be observed between the outcomes of measurements applied on half of an entangled state and the resulting post-measured states that are left with the other party. From an operational point of view, a steering test can be seen as an entanglement test where one of the parties performs uncharacterised measurements. Thus, quantum steering is a form of quantum inseparability that lies in between the well-known notions of Bell nonlocality and entanglement. Moreover, quantum steering is also related to several asymmetric quantum information protocols where some of the parties are considered untrusted. Because of these facts, quantum steering has received a lot of attention both theoretically and experimentally. The main goal of this review is to give an overview of how to characterise quantum steering through semidefinite programming. This characterisation provides efficient numerical methods to address a number of problems, including steering detection, quantification, and applications. We also give a brief overview of some important results that are not directly related to semidefinite programming. Finally, we make available a collection of semidefinite programming codes that can be used to study the topics discussed in this article.

  8. Monkey steering responses reveal rapid visual-motor feedback.

    Directory of Open Access Journals (Sweden)

    Seth W Egger

    Full Text Available The neural mechanisms underlying primate locomotion are largely unknown. While behavioral and theoretical work has provided a number of ideas of how navigation is controlled, progress will require direct physiolgical tests of the underlying mechanisms. In turn, this will require development of appropriate animal models. We trained three monkeys to track a moving visual target in a simple virtual environment, using a joystick to control their direction. The monkeys learned to quickly and accurately turn to the target, and their steering behavior was quite stereotyped and reliable. Monkeys typically responded to abrupt steps of target direction with a biphasic steering movement, exhibiting modest but transient overshoot. Response latencies averaged approximately 300 ms, and monkeys were typically back on target after about 1 s. We also exploited the variability of responses about the mean to explore the time-course of correlation between target direction and steering response. This analysis revealed a broad peak of correlation spanning approximately 400 ms in the recent past, during which steering errors provoke a compensatory response. This suggests a continuous, visual-motor loop controls steering behavior, even during the epoch surrounding transient inputs. Many results from the human literature also suggest that steering is controlled by such a closed loop. The similarity of our results to those in humans suggests the monkey is a very good animal model for human visually guided steering.

  9. On fractional control method for four-wheel-steering vehicle

    Institute of Scientific and Technical Information of China (English)

    CHEN Ning; CHEN Nan; CHEN YanDong

    2009-01-01

    Four-wheel-steering (4WS) system can enhance vehicle cornering ability by steering the rear wheels in accordance with the front wheels steering and vehicle status. With such steering control system, it becomes possible to improve the lateral stability and handling performance, in this paper, a new control method for 4WS vehicle is proposed, its rear wheels steering angle is in accordance with the angle of front wheels steering and vehicle yaw rate, and the effects of front wheels steering angle velocity are considered by adopting the fractional derivative theory. Some design specifications for control law are also given. The effects of the control method are verified by a kind of numerical scheme presented in this paper. The dynamic characteristics such as the side-slip angle and the yaw angle velocity of the vehicle gravity center are compared among three kinds of vehicles with different control methods. And the kinematics characteristics such as turning radius between 4WS and 2WS are also discussed. Nu-merical simulation shows that the control method presented can improve the transient response and reduce the turning radius of 4WS vehicle.

  10. On fractional control method for four-wheel-steering vehicle

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Four-wheel-steering (4WS) system can enhance vehicle cornering ability by steering the rear wheels in accordance with the front wheels steering and vehicle status. With such steering control system, it becomes possible to improve the lateral stability and handling performance. In this paper, a new control method for 4WS vehicle is proposed, its rear wheels steering angle is in accordance with the angle of front wheels steering and vehicle yaw rate, and the effects of front wheels steering angle velocity are considered by adopting the fractional derivative theory. Some design specifications for control law are also given. The effects of the control method are verified by a kind of numerical scheme presented in this paper. The dynamic characteristics such as the side-slip angle and the yaw angle velocity of the vehicle gravity center are compared among three kinds of vehicles with different control methods. And the kinematics characteristics such as turning radius between 4WS and 2WS are also discussed. Nu- merical simulation shows that the control method presented can improve the transient response and reduce the turning radius of 4WS vehicle.

  11. Lean color characteristics of bullock and steer beef.

    Science.gov (United States)

    Shackelford, S D; Purser, D E; Smith, G C; Griffin, C L; Stiffler, D M; Savell, J W

    1992-02-01

    Twelve young bulls and 12 steers were slaughtered and the carcasses were fabricated at 48 h postmortem. Top rounds, bottom rounds, and rib eyes were vacuum-packaged and stored at 0 degrees C until 21 d postmortem. After subprimal storage, steaks were removed from each cut and displayed under simulated retail conditions for 3 d. Consumer panelists (n = 110) showed little difference in buying preference for top round, bottom round, and rib eye steaks from steers vs bullocks. Also, consumer panelists could not detect color differences between steaks from steers and bullocks. Experienced panelists (n = 6) detected brighter (P less than .05) muscle color for top round and rib eye steaks from steers but detected no difference in muscle color of bottom round steaks from bullocks and steers. Generally, overall desirability scores favored steaks from steer carcasses. This was particularly true of rib eye steaks. Sex-class of carcass did not affect aerobic plate counts of top round, bottom round, or rib eye steaks either before or after 3 d of retail display. Muscle pH was lower for top round and rib eye steaks from steer carcasses; however, the magnitude of this difference was not large enough to affect retail display stability. Muscle pH of bottom round steaks was not affected by sex-class. Although experienced panelists could detect differences in visual appearance of beef retail cuts from steers and bullocks, consumer panelists did not show a clear purchase preference for steer vs bullock beef. These data suggest that beef retail cuts from bullocks are acceptable in visual appearance.

  12. Selection and Simulation of Electric Steering Gear Control System

    Directory of Open Access Journals (Sweden)

    Xin Wang

    2013-06-01

    Full Text Available For the electric steering gear control systems, the principle of the system is introduced. Specific model and parameters are selected to deduce the optimal combination of control system and choices method of the steering system model is determined. The transfer function of motor according to the parameters is achieved and simulation results are gained based on MATLAB. Simulation results show that this method can meet the performance requirements of electric steering gear, the control method is simple and easy to work to achieve.

  13. FLOW CHARACTERISTICS FORMATION OF POWER STEERING WITH ROTARY DISTRIBUTOR

    OpenAIRE

    Mikhailov, V; E. Strock

    2012-01-01

    In order to obtain an adequate mathematical model of vehicle hydro-mechanical steering which is  equipped with a steering mechanism combined with power steering and a rotary distributor  it is initially   necessary to get current consumption values in the units of hydraulic scheme which are determined by dynamic changes of flow passages of pressure and drain circuits according to turning angle of the distributor. Such characteristics are usually determined experimentally.The paper  proposes  ...

  14. Steering Control of Wheeled Armored Vehicle with Brushless DC Motor

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Considering the steering characters of one type of wheeled armored vehicle, a brushless direct current (DC) motor is adapted as the actuator for steering control. After investigating the known algorithms, one kind of algorithm, which combines the fuzzy logic control with the self-adapting PID control and the startup and pre-brake control, is put forward. Then a test-bed is constructed, and an experiment is conducted. The result of experiment confirms the validity of this algorithm in steering control of wheeled armored vehicle with brushless DC motor.

  15. Dynamic characteristics of hydraulic power steering system with accumulator in load-haul-dump vehicle

    Institute of Scientific and Technical Information of China (English)

    杨忠炯; 何清华; 柳波

    2004-01-01

    Using hydraulic power steering system of model EIMCO 922 load-haul-dump vehicle as a simulation example, the dynamic characteristics of hydraulic power steering system in load-haul-dump vehicle were simulated and discussed with SIMULINK software and hydraulic control theory. The results show that the dynamic characteristics of hydraulic power steering system are improved obviously by using bladder accumulator, the hydraulic power steering system of model EIMCO 922 load-haul-dump vehicle generates vibration at the initial stage under the normal steering condition of pulse input, and its static response time is 0.25 s shorter than that without bladder accumulator. Under the normal steering working condition, the capacity of steering accumulator for absorbing pulse is directly proportional to the cross section area of connecting pipeline, and inversely proportional to the length of connecting pipeline. At the same time, the precharge pressure of nitrogen in steering accumulator should be 60%- 80% of the rated minimum working pressure of hydraulic power steering system. Under the abnormal steering working condition, the steering cylinder piston may obtain higher motion velocity, and the dynamic response velocity of hydraulic power steering system can be increased by reducing the pressure drop of hydraulic pipelines between the accumulator and steering cylinder and by increasing the rated pressure of hydraulic power steering system, but the dynamic characteristics of hydraulic power steering system in load-haul-dump vehicle have nothing to do with the precharge pressure of nitrogen in steering accumulator.

  16. Impact of feedback torque level on perceived comfort and control in steer-by-wire systems

    NARCIS (Netherlands)

    Anand, S.; Terken, J.; Hogema, J.H.; Martens, J.B.

    2012-01-01

    Steer-by-Wire systems enable designers to offer completely personalized steering feel to drivers, unlike existing steering systems that offer limited or no personalization. In this paper we focus on feedback torque level, a significant factor for steering feel. Earlier studies indicate that the pref

  17. 46 CFR 58.25-10 - Main and auxiliary steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Main and auxiliary steering gear. 58.25-10 Section 58.25... AUXILIARY MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-10 Main and auxiliary steering gear. (a) Power-operated main and auxiliary steering gear must be separate systems that are independent throughout...

  18. 46 CFR 196.37-33 - Instructions for changing steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Instructions for changing steering gear. 196.37-33... steering gear. (a) Instructions in at least 1/2 inch letters and figures shall be posted in the steering engineroom, relating in order, the different steps to be taken in changing to the emergency steering...

  19. Information processing through a bio-based redox capacitor: signatures for redox-cycling.

    Science.gov (United States)

    Liu, Yi; Kim, Eunkyoung; White, Ian M; Bentley, William E; Payne, Gregory F

    2014-08-01

    Redox-cycling compounds can significantly impact biological systems and can be responsible for activities that range from pathogen virulence and contaminant toxicities, to therapeutic drug mechanisms. Current methods to identify redox-cycling activities rely on the generation of reactive oxygen species (ROS), and employ enzymatic or chemical methods to detect ROS. Here, we couple the speed and sensitivity of electrochemistry with the molecular-electronic properties of a bio-based redox-capacitor to generate signatures of redox-cycling. The redox capacitor film is electrochemically-fabricated at the electrode surface and is composed of a polysaccharide hydrogel with grafted catechol moieties. This capacitor film is redox-active but non-conducting and can engage diffusible compounds in either oxidative or reductive redox-cycling. Using standard electrochemical mediators ferrocene dimethanol (Fc) and Ru(NH3)6Cl3 (Ru(3+)) as model redox-cyclers, we observed signal amplifications and rectifications that serve as signatures of redox-cycling. Three bio-relevant compounds were then probed for these signatures: (i) ascorbate, a redox-active compound that does not redox-cycle; (ii) pyocyanin, a virulence factor well-known for its reductive redox-cycling; and (iii) acetaminophen, an analgesic that oxidatively redox-cycles but also undergoes conjugation reactions. These studies demonstrate that the redox-capacitor can enlist the capabilities of electrochemistry to generate rapid and sensitive signatures of biologically-relevant chemical activities (i.e., redox-cycling).

  20. FLEXIBLE 2-DOF STEERING MODEL OF MULTI-AXLE HEAVY-DUTY VEHICLE

    Institute of Scientific and Technical Information of China (English)

    Yang Bo; Wang Xuelin; Hu Yujin; Li Chenggang

    2004-01-01

    A flexible two degrees of freedom (2-DOF) steering model of multi-axle vehicle (MAV) is presented with considering the effect of frame flexibility based on the classic 2-DOF model. A method to calculate the frame flexibility is derived by using three moments equation. The steering stability of MAV is analyzed. The steering performance of MAV is also researched in frequency domain. Simulation results show that the dynamic effects of flexible model are more severe than rigid model and the flexible effect of frame will weaken the steering stability of MAV. Different disposals of steering axles lead to different steering characteristics of MAV. The in-phase steering mode improves the steering characteristics and stability at high speed. The anti-phase steering mode increases the steering mobility at low vehicle speed.

  1. Molecular analysis of Ku redox regulation

    Directory of Open Access Journals (Sweden)

    Shatilla Andrea

    2009-08-01

    Full Text Available Abstract Background DNA double-strand breaks (DSBs can occur in response to ionizing radiation (IR, radiomimetic agents and from endogenous DNA-damaging reactive oxygen metabolites. Unrepaired or improperly repaired DSBs are potentially the most lethal form of DNA damage and can result in chromosomal translocations and contribute to the development of cancer. The principal mechanism for the repair of DSBs in humans is non-homologous end-joining (NHEJ. Ku is a key member of the NHEJ pathway and plays an important role in the recognition step when it binds to free DNA termini. Ku then stimulates the assembly and activation of other NHEJ components. DNA binding of Ku is regulated by redox conditions and evidence from our laboratory has demonstrated that Ku undergoes structural changes when oxidized that results in a reduction in DNA binding activity. The C-terminal domain and cysteine 493 of Ku80 were investigated for their contribution to redox regulation of Ku. Results We effectively removed the C-terminal domain of Ku80 generating a truncation mutant and co-expressed this variant with wild type Ku70 in an insect cell system to create a Ku70/80ΔC heterodimer. We also generated two single amino acid variants of Cys493, replacing this amino acid with either an alanine (C493A or a serine (C493S, and over-expressed the variant proteins in SF9 insect cells in complex with wild type Ku70. Neither the truncation nor the amino acid substitutions alters protein expression or stability as determined by SDS-PAGE and Western blot analysis. We show that the C493 mutations do not alter the ability of Ku to bind duplex DNA in vitro under reduced conditions while truncation of the Ku80 C-terminus slightly reduced DNA binding affinity. Diamide oxidation of cysteines was shown to inhibit DNA binding similarly for both the wild-type and all variant proteins. Interestingly, differential DNA binding activity following re-reduction was observed for the Ku70/80

  2. Lung extracellular matrix and redox regulation.

    Science.gov (United States)

    Watson, Walter H; Ritzenthaler, Jeffrey D; Roman, Jesse

    2016-08-01

    Pulmonary fibrosis affects millions worldwide and, even though there has been a significant investment in understanding the processes involved in wound healing and maladaptive repair, a complete understanding of the mechanisms responsible for lung fibrogenesis eludes us, and interventions capable of reversing or halting disease progression are not available. Pulmonary fibrosis is characterized by the excessive expression and uncontrolled deposition of extracellular matrix (ECM) proteins resulting in erosion of the tissue structure. Initially considered an 'end-stage' process elicited after injury, these events are now considered pathogenic and are believed to contribute to the course of the disease. By interacting with integrins capable of signal transduction and by influencing tissue mechanics, ECM proteins modulate processes ranging from cell adhesion and migration to differentiation and growth factor expression. In doing so, ECM proteins help orchestrate complex developmental processes and maintain tissue homeostasis. However, poorly controlled deposition of ECM proteins promotes inflammation, fibroproliferation, and aberrant differentiation of cells, and has been implicated in the pathogenesis of pulmonary fibrosis, atherosclerosis and cancer. Considering their vital functions, ECM proteins are the target of investigation, and oxidation-reduction (redox) reactions have emerged as important regulators of the ECM. Oxidative stress invariably accompanies lung disease and promotes ECM expression directly or through the overproduction of pro-fibrotic growth factors, while affecting integrin binding and activation. In vitro and in vivo investigations point to redox reactions as targets for intervention in pulmonary fibrosis and related disorders, but studies in humans have been disappointing probably due to the narrow impact of the interventions tested, and our poor understanding of the factors that regulate these complex reactions. This review is not meant to

  3. Lung extracellular matrix and redox regulation

    Directory of Open Access Journals (Sweden)

    Walter H. Watson

    2016-08-01

    Full Text Available Pulmonary fibrosis affects millions worldwide and, even though there has been a significant investment in understanding the processes involved in wound healing and maladaptive repair, a complete understanding of the mechanisms responsible for lung fibrogenesis eludes us, and interventions capable of reversing or halting disease progression are not available. Pulmonary fibrosis is characterized by the excessive expression and uncontrolled deposition of extracellular matrix (ECM proteins resulting in erosion of the tissue structure. Initially considered an ‘end-stage’ process elicited after injury, these events are now considered pathogenic and are believed to contribute to the course of the disease. By interacting with integrins capable of signal transduction and by influencing tissue mechanics, ECM proteins modulate processes ranging from cell adhesion and migration to differentiation and growth factor expression. In doing so, ECM proteins help orchestrate complex developmental processes and maintain tissue homeostasis. However, poorly controlled deposition of ECM proteins promotes inflammation, fibroproliferation, and aberrant differentiation of cells, and has been implicated in the pathogenesis of pulmonary fibrosis, atherosclerosis and cancer. Considering their vital functions, ECM proteins are the target of investigation, and oxidation–reduction (redox reactions have emerged as important regulators of the ECM. Oxidative stress invariably accompanies lung disease and promotes ECM expression directly or through the overproduction of pro-fibrotic growth factors, while affecting integrin binding and activation. In vitro and in vivo investigations point to redox reactions as targets for intervention in pulmonary fibrosis and related disorders, but studies in humans have been disappointing probably due to the narrow impact of the interventions tested, and our poor understanding of the factors that regulate these complex reactions. This

  4. 46 CFR 58.25-70 - Steering-gear control systems.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Steering-gear control systems. 58.25-70 Section 58.25-70... MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-70 Steering-gear control systems. (a) Each power-driven steering-gear system must be provided with at least one steering-gear control system. (b) The main...

  5. Improvement for the steering performance of liquid crystal phased array

    Institute of Scientific and Technical Information of China (English)

    SONG Yan; KONG Ling-jiang; CHEN Jun; ZHU Ying; YANG Jian-yu

    2009-01-01

    Optical phased array technology is introduced and the steering performances of liquid crystal phased array are discussed, several factors affecting the beam steering performances arc analyzed completely, also simple models for some typical factors are developed. Then, a new method based on iterating and modifying the output phase pattern of liquid crystal phase shifters is proposed. Using this method, the modified voltages applied on electrodes of liquid crystal phase shifters can be obtained, after applying the voltages, the influence of factors can be compensated to some extent; the steering angle accu-racy and efficiency with liquid crystal phased array can be improved. Through the simulation for the angle range from 0° to -1°, the error of steering angle can be reduced three orders of magnitude, and the efficiency can be increased almost 30% after several iterations.

  6. Electrical power assisted steering for EVs and HEVs

    Institute of Scientific and Technical Information of China (English)

    Ma Haibo; Yang Ying

    2011-01-01

    Electrical power assisted steering (EPAS) is one of the key components, especially for electrical vehicle. It has attracted much attention for their advantages with respect to improved fuel economy and has been widely adopted as automotive power-steering equipment in recent years. EPS (electrical power steering) controllers contain MCU (microprocessor control unit) to implement the complex control algorithms. EPS control strategy development is the core technology of the whole system. To achieve the better performance of driving, both mechanical structures and electrical structures are totally designed as a whole. Model-based development is recommended to software design. There are several trends about EPS' future, such as high power EPS development, high voltage EPS development and steering-bywire technology.

  7. Steering of Solar Sails Using Optical Lift Force Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This study seeks to look beyond the use of radiation pressure for thrust, and to explore a means of solar navigation whereby a solar craft would be steered by use...

  8. An improved constrained steering law for SGCMGs with DPC

    Institute of Scientific and Technical Information of China (English)

    Lei Jin; Shijie Xu

    2009-01-01

    An improved constrained (IC) steering law for single girnbal control moment gyros (SGCMGs) with deformed pyramid configuration (DPC) is proposed. First of all, the original system with five pyramid configuration (FPC) whose two adjacent gyros are in failure state is reconfigured as a degraded system with DPC. Then, the singular angular momentum hypersurfaces of the original and the degraded systems are plotted via the singular angular momentum equation of SGCMGs. Based on singular surfaces, the differences between FPC and DPC in singularity and momentum envelope are obtained directly, which provide an important reference for steering law design of DPC. Finally, an IC steering law is designed and applied to DPC. The simulation results demonstrate that the IC steering law has advantages in simplicity of calculation, avoidance of singularity and exactness of output torque, which endow the degraded system with fine controllability in a restricted workspace.

  9. FLOW CHARACTERISTICS FORMATION OF POWER STEERING WITH ROTARY DISTRIBUTOR

    Directory of Open Access Journals (Sweden)

    V. Mikhailov

    2012-01-01

    Full Text Available In order to obtain an adequate mathematical model of vehicle hydro-mechanical steering which is  equipped with a steering mechanism combined with power steering and a rotary distributor  it is initially   necessary to get current consumption values in the units of hydraulic scheme which are determined by dynamic changes of flow passages of pressure and drain circuits according to turning angle of the distributor. Such characteristics are usually determined experimentally.The paper  proposes  a sequence which is recommended for determination of consumption characteristics which is formed with due account of multi-directional kinematic perturbations, mechanical clearance, possible emergence of hydraulic backlash and desired throttling law. The factors account makes it possible to obtain an acceptable mathematical analogue of a hydro-mechanical steering for execution of robust investigations. 

  10. A control theoretic model of driver steering behavior

    Science.gov (United States)

    Donges, E.

    1977-01-01

    A quantitative description of driver steering behavior such as a mathematical model is presented. The steering task is divided into two levels: (1) the guidance level involving the perception of the instantaneous and future course of the forcing function provided by the forward view of the road, and the response to it in an anticipatory open-loop control mode; (2) the stabilization level whereby any occuring deviations from the forcing function are compensated for in a closed-loop control mode. This concept of the duality of the driver's steering activity led to a newly developed two-level model of driver steering behavior. Its parameters are identified on the basis of data measured in driving simulator experiments. The parameter estimates of both levels of the model show significant dependence on the experimental situation which can be characterized by variables such as vehicle speed and desired path curvature.

  11. Acupuncture mechanism and redox equilibrium.

    Science.gov (United States)

    Zeng, Xiang-Hong; Li, Qian-Qian; Xu, Qian; Li, Fang; Liu, Cun-Zhi

    2014-01-01

    Oxidative stress participates in the pathological process of various diseases. Acupuncture is a component of the health care system in China that can be traced back for at least 3000 years. Recently, increased evidences indicate that acupuncture stimulation could reduce oxidative damage in organisms under pathological state, but the exact mechanism remains unclear. This review focuses on the emerging links between acupuncture and redox modulation in various disorders, such as vascular dementia, Parkinson's disease, and hypertension, ranging from redox system, antioxidant system, anti-inflammatory system, and nervous system to signaling pathway. Although the molecular and cellular pathways studies of acupuncture effect on oxidative stress are preliminary, they represent an important step forward in the research of acupuncture antioxidative effect.

  12. Acupuncture Mechanism and Redox Equilibrium

    OpenAIRE

    Xiang-Hong Zeng; Qian-Qian Li; Qian Xu; Fang Li; Cun-Zhi Liu

    2014-01-01

    Oxidative stress participates in the pathological process of various diseases. Acupuncture is a component of the health care system in China that can be traced back for at least 3000 years. Recently, increased evidences indicate that acupuncture stimulation could reduce oxidative damage in organisms under pathological state, but the exact mechanism remains unclear. This review focuses on the emerging links between acupuncture and redox modulation in various disorders, such as vascular dementi...

  13. Redox-dependent regulation of epidermal growth factor receptor signaling

    Directory of Open Access Journals (Sweden)

    David E. Heppner

    2016-08-01

    Full Text Available Tyrosine phosphorylation-dependent cell signaling represents a unique feature of multicellular organisms, and is important in regulation of cell differentiation and specialized cell functions. Multicellular organisms also contain a diverse family of NADPH oxidases (NOXs that have been closely linked with tyrosine kinase-based cell signaling and regulate tyrosine phosphorylation via reversible oxidation of cysteine residues that are highly conserved within many proteins involved in this signaling pathway. An example of redox-regulated tyrosine kinase signaling involves the epidermal growth factor receptor (EGFR, a widely studied receptor system with diverse functions in normal cell biology as well as pathologies associated with oxidative stress such as cancer. The purpose of this Graphical Redox Review is to highlight recently emerged concepts with respect to NOX-dependent regulation of this important signaling pathway.

  14. Redox signaling in acute pancreatitis

    Directory of Open Access Journals (Sweden)

    Salvador Pérez

    2015-08-01

    Full Text Available 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.

  15. 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.

  16. The ATLAS High Level Trigger Steering

    CERN Document Server

    Berger, N; Eifert, T; Fischer, G; George, S; Haller, J; Höcker, A; Masik, J; Zur Nedden, M; Pérez-Réale, V; Risler, C; Schiavi, C; Stelzer, J; Wu, X; International Conference on Computing in High Energy and Nuclear Physics

    2008-01-01

    The High Level Trigger (HLT) of the ATLAS experiment at the Large Hadron Collider receives events which pass the LVL1 trigger at ~75 kHz and has to reduce the rate to ~200 Hz while retaining the most interesting physics. It is a software trigger and performs the reduction in two stages: the LVL2 trigger and the Event Filter (EF). At the heart of the HLT is the Steering software. To minimise processing time and data transfers it implements the novel event selection strategies of seeded, step-wise reconstruction and early rejection. The HLT is seeded by regions of interest identified at LVL1. These and the static configuration determine which algorithms are run to reconstruct event data and test the validity of trigger signatures. The decision to reject the event or continue is based on the valid signatures, taking into account pre-scale and pass-through. After the EF, event classification tags are assigned for streaming purposes. Several powerful new features for commissioning and operation have been added: co...

  17. Membranes for Redox Flow Battery Applications

    OpenAIRE

    Maria Skyllas-Kazacos; Aishwarya Parasuraman; Tuti Mariana Lim; Suminto Winardi; Helen Prifti

    2012-01-01

    The need for large scale energy storage has become a priority to integrate renewable energy sources into the electricity grid. Redox flow batteries are considered the best option to store electricity from medium to large scale applications. However, the current high cost of redox flow batteries impedes the wide spread adoption of this technology. The membrane is a critical component of redox flow batteries as it determines the performance as well as the economic viability of the batteries. Th...

  18. Backwards planning approach for rapid attitude maneuvers steering

    Science.gov (United States)

    Verbin, D.

    Remote sensing satellites are often built with payloads that do not include line of sight steering mechanisms. In cases, when frequent line of sight retargeting is required, there is a need for efficient actuators and control schemes that would support rapid attitude manoeuvring together with adequate pointing accuracy and stability between the manoeuvres. Within this frame, this research develops the Backwards Planning approach as one of the possible control methods for rapid manoeuvring. The method is based on state feedback and combines time efficient together with straight forward computation flow. Novel efficient methods to execute the Backwards Planning Control in the 3D attitude space are proposed here. The methods refer both for the first saturated control phase of the manoeuvre and for the last braking phase. The actuators used for the spacecraft control in this research are either Reaction Wheels (RWs) or Single Gimbal Control Moments Gyros (SGCMGs) or both of them together. The advantage of the SGCMG is in rapid rotational manoeuvring, but their application for high quality pointing requires very accurate gimbal mechanisms. On the other hand, RWs are usually more suitable for accurate pointing, but their torque to power performance is inferior in manoeuvring. It is shown that the coordination of SGCMGs and RWs together enables to draw more performance from the SGCMGs in terms of agility and meet the pointing requirements between manoeuvres where only the RWs are used. Novel SGCMG steering laws are suggested as well. While the steering laws determine the required angular rate for each gimbal, most steering laws are defined in the angular momentum domain and output the gimbals angular rates to produce a given required torque or angular momentum increment. This research however, practices a novel steering law in the gimbal angles domain. While both steering laws turn to be dynamically equivalent for small control signals, as in the steady state, it is shown

  19. Redox conditions for mantle plumes

    Science.gov (United States)

    Heister, L. E.; Lesher, C. E.

    2005-12-01

    The vanadium to scandium ratio (V/Sc) for basalts from mid-ocean ridge (MOR) and arc environments has been proposed as a proxy for fO2 conditions during partial melting (e.g. [1] and [2]). Contrary to barometric measurements of the fO2 of primitive lavas, the V/Sc ratio of the upper mantle at mid-ocean ridges and arcs is similar, leading previous authors to propose that the upper mantle has uniform redox potential and is well-buffered. We have attempted to broaden the applicability of the V/Sc parameter to plume-influenced localities (both oceanic and continental), where mantle heterogeneities associated with recycled sediments, mafic crust, and metasomatized mantle, whether of shallow or deep origin, exist. We find that primitive basalts from the North Atlantic Igneous Province (NAIP), Hawaii (both the Loa and Kea trends), Deccan, Columbia River, and Siberian Traps show a range of V/Sc ratios that are generally higher (average ~9) than those for MOR (average ~ 6.7) or arc (average ~7) lavas. Based on forward polybaric decompression modeling, we attribute these differences to polybaric melting and melt segregation within the garnet stability field rather than the presence of a more oxidized mantle in plume-influenced settings. Like MORB, the V/Sc ratios for plume-influenced basalts can be accounted for by an oxidation state approximately one log unit below the Ni-NiO buffer (NNO-1). Our analysis suggests that source heterogeneities have little, if any, resolvable influence on mantle redox conditions, although they have significant influence on the trace element and isotopic composition of mantle-derived melts. We suggest that variations in the redox of erupted lavas is largely a function of shallow lithospheric processes rather than intrinsic to the mantle source, regardless of tectonic setting. [1] Li and Lee (2004) EPSL, [2] Lee et al. (2005) J. of Petrology

  20. A redox-sensitive yellow fluorescent protein sensor for monitoring nuclear glutathione redox dynamics.

    Science.gov (United States)

    Banach-Latapy, Agata; Dardalhon, Michèle; Huang, Meng-Er

    2015-01-01

    Intracellular redox homeostasis is crucial for many cellular functions, but accurate measurements of cellular compartment-specific redox states remain technically challenging. Genetically encoded biosensors, including the glutathione-specific redox-sensitive yellow fluorescent protein (rxYFP), provide an alternative approach to overcome the limitations of conventional glutathione/glutathione disulfide (GSH/GSSG) redox measurements. In this chapter we describe methods to measure the nuclear rxYFP redox state in human cells by a redox Western blot technique. A nucleus-targeted rxYFP sensor can be used to sense nuclear steady-state and dynamic redox changes in response to oxidative stress. Complementary to existing redox sensors and conventional redox measurements, nucleus-targeted rxYFP sensors provide a novel tool for examining nuclear redox homeostasis in mammalian cells, permitting high-resolution readout of steady glutathione state and dynamics of redox changes. The technique described may be used with minimal variations to study the effects of stress conditions which lead to glutathione redox changes.

  1. Oxygen in human health from life to death – An approach to teaching redox biology and signaling to graduate and medical students

    Directory of Open Access Journals (Sweden)

    Margaret M. Briehl

    2015-08-01

    Full Text Available In the absence of oxygen human life is measured in minutes. In the presence of oxygen, normal metabolism generates reactive species (ROS that have the potential to cause cell injury contributing to human aging and disease. Between these extremes, organisms have developed means for sensing oxygen and ROS and regulating their cellular processes in response. Redox signaling contributes to the control of cell proliferation and death. Aberrant redox signaling underlies many human diseases. The attributes acquired by altered redox homeostasis in cancer cells illustrate this particularly well. This teaching review and the accompanying illustrations provide an introduction to redox biology and signaling aimed at instructors of graduate and medical students.

  2. The dipole moment of the electron carrier adrenodoxin is not critical for redox partner interaction and electron transfer.

    Science.gov (United States)

    Hannemann, Frank; Guyot, Arnaud; Zöllner, Andy; Müller, Jürgen J; Heinemann, Udo; Bernhardt, Rita

    2009-07-01

    Dipole moments of proteins arise from helical dipoles, hydrogen bond networks and charged groups at the protein surface. High protein dipole moments were suggested to contribute to the electrostatic steering between redox partners in electron transport chains of respiration, photosynthesis and steroid biosynthesis, although so far experimental evidence for this hypothesis was missing. In order to probe this assumption, we changed the dipole moment of the electron transfer protein adrenodoxin and investigated the influence of this on protein-protein interactions and electron transfer. In bovine adrenodoxin, the [2Fe-2S] ferredoxin of the adrenal glands, a dipole moment of 803 Debye was calculated for a full-length adrenodoxin model based on the Adx(4-108) and the wild type adrenodoxin crystal structures. Large distances and asymmetric distribution of the charged residues in the molecule mainly determine the observed high value. In order to analyse the influence of the resulting inhomogeneous electric field on the biological function of this electron carrier the molecular dipole moment was systematically changed. Five recombinant adrenodoxin mutants with successively reduced dipole moment (from 600 to 200 Debye) were analysed for their redox properties, their binding affinities to the redox partner proteins and for their function during electron transfer-dependent steroid hydroxylation. None of the mutants, not even the quadruple mutant K6E/K22Q/K24Q/K98E with a dipole moment reduced by about 70% showed significant changes in the protein function as compared with the unmodified adrenodoxin demonstrating that neither the formation of the transient complex nor the biological activity of the electron transfer chain of the endocrine glands was affected. This is the first experimental evidence that the high dipole moment observed in electron transfer proteins is not involved in electrostatic steering among the proteins in the redox chain.

  3. The Yin and Yang of redox regulation.

    Science.gov (United States)

    Olsen, Lars Folke; Issinger, Olaf-Georg; Guerra, Barbara

    2013-01-01

    Mammalian cells produce reactive oxygen and nitrogen species (ROS/RNOS) in response to an oxidative environment. Powerful antioxidant mechanisms have been developed in order to avoid oxidative stress by contributing to the maintenance of redox homeostasis. Traditionally, accumulation of ROS/RNOS is considered deleterious for cells as it can lead to loss of cellular function, aging, and cell death. Consequently, ROS/RNOS imbalance has been implicated in the etiology and/or progression of numerous pathologies such as cardiovascular diseases, inflammation, and cancer. An interesting concept that has emerged more recently is that not only have cells developed efficient systems to cope with ROS/RNOS accumulation but they have also learned to profit of them under certain circumstances. This notion is supported by data showing that ROS/RNOS can act as signaling molecules affecting the function and activity of a multiplicity of protein kinases and phosphatases controlling cellular homeostasis. This review does not provide an exhaustive overview of molecular mechanisms linked to ROS/RNOS generation and processing but includes relevant examples highlighting the dichotomic nature of these small molecules and the multitude of effects elicited by their accumulation. This aspect of ROS/RNOS ought to be taken into account particularly in novel therapeutic setups that aim to achieve high efficiency and minimal or no side effects.

  4. Redox protective potential of fruits and vegetables: A review

    Directory of Open Access Journals (Sweden)

    Zainab Tahir

    2015-08-01

    Full Text Available Although oxidation reactions are crucial for life, they can also be damaging to cells and tissues, causing variety of chronic ailments like, aging, cancer, autoimmune problems, cardiovascular and neurodegenerative disorders etc. Redox protective systems are present in body for general immunization against free radicals, which can be supported by antioxidants that we take in our daily diet. Natural antioxidants such as flavonoids, hydrolysable tannins, coumarins, xanthones, phenolics, terpenoids, ascorbic acid, carotenoids and proanthocyanins are found in various plant products, including fruits, leaves, seeds oils, and juices. This review gives a brief account of research reports on fruits and vegetables which provide free radical scavenging compounds to the body.

  5. Redox protective potential of fruits and vegetables:A review

    Institute of Scientific and Technical Information of China (English)

    Zainab Tahir; MuhammadArshad; Sunbal Khalil Chaudhari

    2015-01-01

    Although oxidation reactions are crucial for life, they can also be damaging to cells and tissues, causing variety of chronic ailments like, aging, cancer, autoimmune problems, cardiovascular and neurodegenerative disorders etc. Redox protective systems are present in body for general immunization against free radicals, which can be supported by antioxidants that we take in our daily diet. Natural antioxidants such as flavonoids, hydrolysable tannins, coumarins, xanthones, phenolics, terpenoids, ascorbic acid, carotenoids and proanthocyanins are found in various plant products, including fruits, leaves, seeds oils, and juices. This review gives a brief account of research reports on fruits and vegetables which provide free radical scavenging compounds to the body.

  6. Redox pioneer: professor Barry Halliwell.

    Science.gov (United States)

    Pervaiz, Shazib

    2011-05-01

    Professor Barry Halliwell is recognized as a Redox Pioneer because he has published eight articles on redox biology that have been each cited more than 1000 times, and 158 articles that have been each cited more than 100 times. His contributions go back as far as 1976, when he was involved in elucidation of the Foyer-Halliwell-Asada cycle, an efficient mechanism for preventing oxidative damage to chloroplasts. His subsequent work established the important role of iron and zinc in free radical reactions and their relevance to human pathologies. Professor Halliwell is also a leader in developing novel methodology for detecting free radical intermediates in vivo, and his contributions to our knowledge of reactive nitrogen species are highly significant. His sustained excellence won him the top-cited scientist award in the United Kingdom in biomedical sciences in 1999, and in 2003 he was recognized as a highly cited scientist by Institute of Scientific Information (ISI) for work on plant antioxidants, and the same year ranked 28 out of 5494 biochemists/biologists for scientific impact. Two pieces of his scholarly work have been listed as Citation Classics by ISI, and in 2007 his laboratory was ranked number 1 worldwide based on highest citation score in research on free radicals.

  7. A Parallel and Distributed Surrogate Model Implementation for Computational Steering

    KAUST Repository

    Butnaru, Daniel

    2012-06-01

    Understanding the influence of multiple parameters in a complex simulation setting is a difficult task. In the ideal case, the scientist can freely steer such a simulation and is immediately presented with the results for a certain configuration of the input parameters. Such an exploration process is however not possible if the simulation is computationally too expensive. For these cases we present in this paper a scalable computational steering approach utilizing a fast surrogate model as substitute for the time-consuming simulation. The surrogate model we propose is based on the sparse grid technique, and we identify the main computational tasks associated with its evaluation and its extension. We further show how distributed data management combined with the specific use of accelerators allows us to approximate and deliver simulation results to a high-resolution visualization system in real-time. This significantly enhances the steering workflow and facilitates the interactive exploration of large datasets. © 2012 IEEE.

  8. Signal Processing Strategies for Cochlear Implants Using Current Steering

    Directory of Open Access Journals (Sweden)

    Waldo Nogueira

    2009-01-01

    Full Text Available In contemporary cochlear implant systems, the audio signal is decomposed into different frequency bands, each assigned to one electrode. Thus, pitch perception is limited by the number of physical electrodes implanted into the cochlea and by the wide bandwidth assigned to each electrode. The Harmony HiResolution bionic ear (Advanced Bionics LLC, Valencia, CA, USA has the capability of creating virtual spectral channels through simultaneous delivery of current to pairs of adjacent electrodes. By steering the locus of stimulation to sites between the electrodes, additional pitch percepts can be generated. Two new sound processing strategies based on current steering have been designed, SpecRes and SineEx. In a chronic trial, speech intelligibility, pitch perception, and subjective appreciation of sound were compared between the two current steering strategies and standard HiRes strategy in 9 adult Harmony users. There was considerable variability in benefit, and the mean results show similar performance with all three strategies.

  9. Application of H infinite control to ship steering system

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Because the general object of ship steering control system is singular, the state of rudder force and the state of disturbance are separated, and the generalized yaw output disturbance is obtained. Furthermore, singular system control problem of ship yaw and sway coupled system is transferred into nonsingular standard control problem. Then according to the linear fractional denoting algorithm of the rational function parameter perturbation system, the Linear Fractional Transform (LFT) model of yaw and sway coupled motion is solved, which is used to design the ship steering robust control system. For the ship steering system with the uncertain parameters, the robust control law is designed based on H∞μ-synthesis. And the robust performance of the system is analyzed and the simulation validation is made. Simulation results show that the designed control system has excellent control effect and robustness.

  10. Field Test of Wake Steering at an Offshore Wind Farm

    Energy Technology Data Exchange (ETDEWEB)

    Fleming, Paul; Annoni, Jennifer; Shah, Jigar J.; Wang, Linpeng; Ananthan, Shreyas; Zhang, Zhijun; Hutchings, Kyle; Wang, Peng; Chen, Weiguo; Chen, Lin

    2017-02-06

    In this paper, a field test of wake steering control is presented. The field test is the result of a collaboration between the National Renewable Energy Laboratory (NREL) and Envision Energy, a smart energy management company and turbine manufacturer. In the campaign, an array of turbines within an operating commercial offshore wind farm in China have the normal yaw controller modified to implement wake steering according to a yaw control strategy. The strategy was designed using NREL wind farm models, including a computational fluid dynamics model, SOWFA, for understanding wake dynamics and an engineering model, FLORIS, for yaw control optimization. Results indicate that, within the certainty afforded by the data, the wake-steering controller was successful in increasing power capture, by amounts similar to those predicted from the models.

  11. Reconfigurable time-steered array-antenna beam former.

    Science.gov (United States)

    Frankel, M Y; Esman, R D

    1997-12-10

    We present and analyze a hardware-optimized technique that provides true-time-delay steering for broadband two-dimensional array-antenna applications. The technique improves on previous approaches by the reduction of the two-dimensional beam-former architecture complexity, by the provision of flexibility in time-delay unit selection, and by the potential reduction of optical loss. The technique relies on a one-dimensional bank of time-delay units to form the required time-delay gradient for proper off-broadside angle steering. A reconfigurable optical interconnection fabric is used to reassign dynamically the connections between the time-delay units and individual array elements of a two-dimensional array to effect the proper steering angle along the off-broadside cone.

  12. Redox characteristics of the eukaryotic cytosol

    DEFF Research Database (Denmark)

    López-Mirabal, H Reynaldo; Winther, Jakob R

    2007-01-01

    (ROS) and glutathionylated proteins are maintained at very low levels. In the present review, recent progress in the understanding of the cytosolic thiol-disulfide redox metabolism and novel analytical approaches to studying cytosolic redox properties are discussed. We will focus on the yeast model...

  13. Characterization of redox proteins using electrochemical methods.

    NARCIS (Netherlands)

    Verhagen, M.F.J.M.

    1995-01-01

    The use of electrochemical techniques in combination with proteins started approximately a decade ago and has since then developed into a powerfull technique for the study of small redox proteins. In addition to the determination of redox potentials, electrochemistry can be used to obtain informatio

  14. Characterization of redox conditions in pollution plumes

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Bjerg, Poul Løgstrup; Banwart, Steven A.

    2000-01-01

    Evalution of redox conditions in groundwater pollution plumes is often a prerequisite for understanding the behviour of the pollutants in the plume and for selecting remediation approaches. Measuring of redox conditions in pollution plumes is, however, a fairly recent issue and yet relative few...

  15. Redox- and non-redox-metal-induced formation of free radicals and their role in human disease.

    Science.gov (United States)

    Valko, Marian; Jomova, Klaudia; Rhodes, Christopher J; Kuča, Kamil; Musílek, Kamil

    2016-01-01

    -tocopherol, glutathione (GSH), carotenoids, flavonoids and antioxidant enzymes which include SOD, catalase and glutathione peroxidase. This review summarizes current views regarding the role of redox-active/inactive metal-induced formation of ROS, and modifications to biomolecules in human disease such as cancer, cardiovascular disease, metabolic disease, Alzheimer's disease, Parkinson's disease, renal disease, blood disorders and other disease. The involvement of metals in DNA repair mechanisms, tumor suppressor functions and interference with signal transduction pathways are also discussed.

  16. Current steering effect of GaN nanoporous structure

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chia-Feng, E-mail: cflin@dragon.nchu.edu.tw [Department of Materials Science and Engineering, National Chung Hsing University, Taichung 402, Taiwan (China); Department of Electrical Engineering, Yale University, New Haven, CT 06520 (United States); Wang, Jing-Hao; Cheng, Po-Fu; Tseng, Wang-Po; Fan, Feng-Hsu; Wu, Kaun-Chun; Lee, Wen-Che [Department of Materials Science and Engineering, National Chung Hsing University, Taichung 402, Taiwan (China); Han, Jung [Department of Electrical Engineering, Yale University, New Haven, CT 06520 (United States)

    2014-11-03

    Current steering effect of InGaN light emitting diode (LED) structure was demonstrated by forming a high resistivity GaN nanoporous structure. Disk-array patterns with current-injection bridge structures were fabricated on InGaN LED devices through a focused ion beam (FIB) system. GaN nanoporous structure was formed around the FIB-drilled holes through a electrochemical (EC) wet-etching process on a n-type GaN:Si layer under the InGaN active layer. High emission intensity and small peak wavelength blueshift phenomenon of the electroluminescence spectra were observed in the EC-treated region compared with the non-treated region. The branch-like nanoporous structure was formed along the lateral etched direction to steer the injection current in 5 μm-width bridge structures. In the FIB-drilled hole structure, high light emission intensity of the central-disk region was observed by enlarging the bridge width to 10 μm, with a 5 μm EC-treated width, that reduced the current steering effect and increased the light scattering effect on the nanoporous structure. The EC-treated GaN:Si nanoporous structure acted as a high light scattering structure and a current steering structure that has potential on the current confinement for vertical cavity surface emitting laser applications. - Highlights: • High resistivity nanoporous-GaN formed in InGaN LED through electrochemical process. • Branch-like nanoporous in 5 μm-width bridge structure can steer the injection current. • Nanoporous GaN acted as s light scattering and current steering structures in InGaN LED.

  17. The Impact of Analog and Bang-Bang Steering Gear Control on Ship's Fuel Economy

    DEFF Research Database (Denmark)

    Nørtoft Thomsen, J. C.; Blanke, Mogens; Reid, R. E.

    1982-01-01

    The latest years have shown considerable efforts towards improving steering generated propulsion losses of ships by the introduction of various sophisticated control algorithms in the autopilots. However, little previous attention has been given to the steering gear control loop, although...

  18. 76 FR 69769 - Annual Public Meeting of the Interagency Steering Committee on Multimedia Environmental Modeling

    Science.gov (United States)

    2011-11-09

    ... indication of citizenship and affiliation) may be faxed or emailed to: Mark Fuhrmann, Environmental Transport... COMMISSION Annual Public Meeting of the Interagency Steering Committee on Multimedia Environmental Modeling... the Federal Interagency Steering Committee on Multimedia Environmental Modeling (ISCMEM) will...

  19. Detailed field test of yaw-based wake steering

    DEFF Research Database (Denmark)

    Fleming, P.; Churchfield, M.; Scholbrock, A.

    2016-01-01

    This paper describes a detailed field-test campaign to investigate yaw-based wake steering. In yaw-based wake steering, an upstream turbine intentionally misaligns its yaw with respect to the inflow to deflect its wake away from a downstream turbine, with the goal of increasing total power...... production. In the first phase, a nacelle-mounted scanning lidar was used to verify wake deflection of a misaligned turbine and calibrate wake deflection models. In the second phase, these models were used within a yaw controller to achieve a desired wake deflection. This paper details the experimental...

  20. Study on Characteristic of Electric Power Assist Steering System

    Institute of Scientific and Technical Information of China (English)

    许镇琳; 王豪; 尚喆; 张海华; 王家军

    2003-01-01

    A pinion-type electric power steering (EPS) equipped on a sedan is reached in this paper. A three-freedom dynamic model of this system is created. The variables affecting assist character is analyzed. The formulas of simpled steering resistance force and the relationship between assist gain and vehicle speed are presented for the first time. Assist character is found based on the parameters of a sedan at last. This assist character is fit for the control rule of the EPS system through analyzing this character. The assist character figure offers reference for system design and control. Furthermore, this research method has generality for assist character of different kinds of vehicles.

  1. Improved LTVMPC design for steering control of autonomous vehicle

    Science.gov (United States)

    Velhal, Shridhar; Thomas, Susy

    2017-01-01

    An improved linear time varying model predictive control for steering control of autonomous vehicle running on slippery road is presented. Control strategy is designed such that the vehicle will follow the predefined trajectory with highest possible entry speed. In linear time varying model predictive control, nonlinear vehicle model is successively linearized at each sampling instant. This linear time varying model is used to design MPC which will predict the future horizon. By incorporating predicted input horizon in each successive linearization the effectiveness of controller has been improved. The tracking performance using steering with front wheel and braking at four wheels are presented to illustrate the effectiveness of the proposed method.

  2. Redox activity of naphthalene secondary organic aerosol

    Directory of Open Access Journals (Sweden)

    R. D. McWhinney

    2013-04-01

    Full Text Available Chamber secondary organic aerosol (SOA from low-NOx photooxidation of naphthalene by hydroxyl radical was examined with respect to its redox cycling behaviour using the dithiothreitol (DTT assay. Naphthalene SOA was highly redox active, consuming DTT at an average rate of 118 ± 14 pmol per minute per μg of SOA material. Measured particle-phase masses of the major previously identified redox active products, 1,2- and 1,4-naphthoquinone, accounted for only 21 ± 3% of the observed redox cycling activity. The redox-active 5-hydroxy-1,4-naphthoquinone was identified as a new minor product of naphthalene oxidation, and including this species in redox activity predictions increased the predicted DTT reactivity to 30 ± 5% of observations. Similar attempts to predict redox behaviour of oxidised two-stroke engine exhaust particles by measuring 1,2-naphthoquinone, 1,4-naphthoquinone and 9,10-phenanthrenequinone predicted DTT decay rates only 4.9 ± 2.5% of those observed. Together, these results suggest that there are substantial unidentified redox-active SOA constituents beyond the small quinones that may be important toxic components of these particles. A gas-to-SOA particle partitioning coefficient was calculated to be (7.0 ± 2.5 × 10−4 m3 μg−1 for 1,4-naphthoquinone at 25 °C. This value suggests that under typical warm conditions, 1,4-naphthoquinone is unlikely to contribute strongly to redox behaviour of ambient particles, although further work is needed to determine the potential impact under conditions such as low temperatures where partitioning to the particle is more favourable. As well, higher order oxidation products that likely account for a substantial fraction of the redox cycling capability of the naphthalene SOA are likely to partition much more strongly to the particle phase.

  3. Redox activity of naphthalene secondary organic aerosol

    Science.gov (United States)

    McWhinney, R. D.; Zhou, S.; Abbatt, J. P. D.

    2013-04-01

    Chamber secondary organic aerosol (SOA) from low-NOx photooxidation of naphthalene by hydroxyl radical was examined with respect to its redox cycling behaviour using the dithiothreitol (DTT) assay. Naphthalene SOA was highly redox active, consuming DTT at an average rate of 118 ± 14 pmol per minute per μg of SOA material. Measured particle-phase masses of the major previously identified redox active products, 1,2- and 1,4-naphthoquinone, accounted for only 21 ± 3% of the observed redox cycling activity. The redox-active 5-hydroxy-1,4-naphthoquinone was identified as a new minor product of naphthalene oxidation, and including this species in redox activity predictions increased the predicted DTT reactivity to 30 ± 5% of observations. Similar attempts to predict redox behaviour of oxidised two-stroke engine exhaust particles by measuring 1,2-naphthoquinone, 1,4-naphthoquinone and 9,10-phenanthrenequinone predicted DTT decay rates only 4.9 ± 2.5% of those observed. Together, these results suggest that there are substantial unidentified redox-active SOA constituents beyond the small quinones that may be important toxic components of these particles. A gas-to-SOA particle partitioning coefficient was calculated to be (7.0 ± 2.5) × 10-4 m3 μg-1 for 1,4-naphthoquinone at 25 °C. This value suggests that under typical warm conditions, 1,4-naphthoquinone is unlikely to contribute strongly to redox behaviour of ambient particles, although further work is needed to determine the potential impact under conditions such as low temperatures where partitioning to the particle is more favourable. As well, higher order oxidation products that likely account for a substantial fraction of the redox cycling capability of the naphthalene SOA are likely to partition much more strongly to the particle phase.

  4. Effects of slow-release urea on ruminal digesta characteristics and growth performance in beef steers

    DEFF Research Database (Denmark)

    Taylor-Edwards, C C; Hibbard, G; Kitts, S E;

    2009-01-01

    Two experiments were conducted to evaluate the effects of slow urea (SRU) versus feed-grade urea on ruminal metabolite characteristics in steers and DMI, gain, and G:F in growing beef steers.......Two experiments were conducted to evaluate the effects of slow urea (SRU) versus feed-grade urea on ruminal metabolite characteristics in steers and DMI, gain, and G:F in growing beef steers....

  5. Steering laws analysis of SGCMGs based on singular value decomposition theory

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jing-rui

    2008-01-01

    The steering laws of single gimbal control moment gyros (SGCMGs) are analyzed and compared in this paper for a spacecraft attitude control system based on singular value decomposition (SVD) theory. The mechanism of steering laws escaping singularity, especially how the steering laws affect singularity of gimbal configuration and the output torque error, is studied using SVD theory. Performance of various steering laws are analyzed and compared quantitatively by simulation. The obtained results can be used as a reference for designers.

  6. 7 CFR 59.103 - Mandatory weekly reporting for steers and heifers.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Mandatory weekly reporting for steers and heifers. 59... (CONTINUED) LIVESTOCK MANDATORY REPORTING Cattle Reporting § 59.103 Mandatory weekly reporting for steers and heifers. (a) In general. The corporate officers or officially designated representatives of each steer...

  7. 46 CFR 78.47-55 - Instructions for changing steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Instructions for changing steering gear. 78.47-55... OPERATIONS Markings for Fire and Emergency Equipment, Etc. § 78.47-55 Instructions for changing steering gear..., relating in order, the different steps to be taken in changing to the emergency steering gear. Each...

  8. 46 CFR 97.37-33 - Instructions for changing steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Instructions for changing steering gear. 97.37-33... steering gear. (a) Instructions in at least 1/2 inch letters and figures shall be posted in the steering... gear. Each clutch, gear, wheel, lever, valve, or switch which is used during the changeover shall...

  9. 46 CFR 130.140 - Steering on OSVs of 100 or more gross tons.

    Science.gov (United States)

    2010-10-01

    ... hydraulic-helm steering-system in paragraph (b) of this section. (b) Each hydraulic-helm steering-system... the vessel at every service speed without being damaged at maximum astern speed. (2) A hydraulic... stops. (6) Either— (i) Two steering pumps in accordance with § 130.130(c)(3) of this part; or (ii)...

  10. Organic Redox Species in Aqueous Flow Batteries: Redox Potentials, Chemical Stability and Solubility

    Science.gov (United States)

    Wedege, Kristina; Dražević, Emil; Konya, Denes; Bentien, Anders

    2016-12-01

    Organic molecules are currently investigated as redox species for aqueous low-cost redox flow batteries (RFBs). The envisioned features of using organic redox species are low cost and increased flexibility with respect to tailoring redox potential and solubility from molecular engineering of side groups on the organic redox-active species. In this paper 33, mainly quinone-based, compounds are studied experimentially in terms of pH dependent redox potential, solubility and stability, combined with single cell battery RFB tests on selected redox pairs. Data shows that both the solubility and redox potential are determined by the position of the side groups and only to a small extent by the number of side groups. Additionally, the chemical stability and possible degradation mechanisms leading to capacity loss over time are discussed. The main challenge for the development of all-organic RFBs is to identify a redox pair for the positive side with sufficiently high stability and redox potential that enables battery cell potentials above 1 V.

  11. Controls on the redox potential of rainwater.

    Science.gov (United States)

    Willey, Joan D; Mullaugh, Katherine M; Kieber, Robert J; Avery, G Brooks; Mead, Ralph N

    2012-12-18

    Hydrogen peroxide acting as a reductant affects the redox potential of rainwater collected at the Bermuda Atlantic Time Series Station, the South Island of New Zealand, the contiguous USA, and the primary study site in Wilmington, NC. Analytical measurements of both halves of redox couples for dissolved iron, mercury, and the nitrate-nitrite-ammonium system can predict the rainwater redox potential measured directly by a platinum electrode. Measurements of these redox couples along with the pH in rain yields pe⁻ between 8 and 11; the half reaction for hydrogen peroxide acting as a reductant using typical rainwater conditions of 15 μM H₂O₂ at pH 4.7 gives pe⁻ = 9.12, where pe⁻ = negative log of the activity of hydrated electrons. Of the six rainwater redox systems investigated, only manganese speciation appeared to be controlled by molecular oxygen (pe⁻ = 15.90). Copper redox speciation was consistent with superoxide acting as a reductant (pe⁻ = 2.7). The concentration of H₂O₂ in precipitation has more than doubled over the preceding decade due to a decrease in SO₂ emissions, which suggests the redox chemistry of rainwater is dynamic and changing, potentially altering the speciation of many organic compounds and trace metals in atmospheric waters.

  12. Apurinic/apyrimidinic endonuclease/redox factor-1 (APE1/Ref-1) redox function negatively regulates NRF2.

    Science.gov (United States)

    Fishel, Melissa L; Wu, Xue; Devlin, Cecilia M; Logsdon, Derek P; Jiang, Yanlin; Luo, Meihua; He, Ying; Yu, Zhangsheng; Tong, Yan; Lipking, Kelsey P; Maitra, Anirban; Rajeshkumar, N V; Scandura, Glenda; Kelley, Mark R; Ivan, Mircea

    2015-01-30

    Apurinic/apyrimidinic endonuclease/redox factor-1 (APE1/Ref-1) (henceforth referred to as Ref-1) is a multifunctional protein that in addition to its base excision DNA repair activity exerts redox control of multiple transcription factors, including nuclear factor κ-light chain enhancer of activated B cells (NF-κB), STAT3, activator protein-1 (AP-1), hypoxia-inducible factor-1 (HIF-1), and tumor protein 53 (p53). In recent years, Ref-1 has emerged as a promising therapeutic target in cancer, particularly in pancreatic ductal carcinoma. Although a significant amount of research has centered on Ref-1, no wide-ranging approach had been performed on the effects of Ref-1 inhibition and transcription factor activity perturbation. Starting with a broader approach, we identified a previously unsuspected effect on the nuclear factor erythroid-related factor 2 (NRF2), a critical regulator of cellular defenses against oxidative stress. Based on genetic and small molecule inhibitor-based methodologies, we demonstrated that repression of Ref-1 potently activates NRF2 and its downstream targets in a dose-dependent fashion, and that the redox, rather than the DNA repair function of Ref-1 is critical for this effect. Intriguingly, our results also indicate that this pathway does not involve reactive oxygen species. The link between Ref-1 and NRF2 appears to be present in all cells tested in vitro, noncancerous and cancerous, including patient-derived tumor samples. In particular, we focused on understanding the implications of the novel interaction between these two pathways in primary pancreatic ductal adenocarcinoma tumor cells and provide the first evidence that this mechanism has implications for overcoming the resistance against experimental drugs targeting Ref-1 activity, with clear translational implications.

  13. Interagency Advanced Power Group -- Steering group meeting minutes

    Energy Technology Data Exchange (ETDEWEB)

    1993-11-18

    This document contains the draft meeting minutes of the Steering Group of the Interagency Advanced Power Group. Included are the discussions resulting from the presentation of working group reports and the results of a discussion of IAPG policies and procedures. In the appendix are the reports of the following working groups: Electrical, Mechanical, Solar, and Systems.

  14. The Analysis of The Fault of Electrical Power Steering

    Directory of Open Access Journals (Sweden)

    Zhang Li Wen

    2016-01-01

    Full Text Available This paper analysis the common fault types of primary Electrical Power Steering system, meanwhile classify every fault. It provides the basis for further troubleshooting and maintenance. At the same time this paper propose a practical working principle of fault-tolerant, in order to make the EPS system more security and durability.

  15. Multifunctional Converter Drive for Automotive Electric Power Steering Systems

    NARCIS (Netherlands)

    Hackner, T.J.

    2013-01-01

    In this thesis it is shown that in the case of an automotive electric power steering system, critical pulse power loads can be decoupled from the power net with a storage element and a multifunctional converter. A multifunctional converter system is proposed because it uses the motor drive system as

  16. Threats and protection for electronically-steered array radars

    NARCIS (Netherlands)

    Janssen, J.P.B.; Monni, S.; Maas, A.P.M.; Vliet, F.E. van

    2008-01-01

    Front-end power overload protection is a vital issue in any electro-magnetic sensor. The issues around active electronically-steered arrays are more recent and pose new threats. Different categories of threats can damage the sensitive electronics in the phased-array radar, like hostile high power el

  17. Steering gameplay behavior in the interactive tag playground

    NARCIS (Netherlands)

    Delden, van Robby; Moreno, Alejandro; Poppe, Ronald; Reidsma, Dennis; Heylen, Dirk; Aarts, Emile; Ruyter, de Boris; Markopoulos, Panos; Loenen, van Evert; Wichert, Reiner; Schouten, Ben; Terken, Jacques; Kranenburg, van Rob; Ouden, den Elke; O'Hare, Gregory

    2014-01-01

    This paper deals with steering player behavior in the Interactive Tag Playground (ITP). The ITP, an ambient environment instrumented with contact-free sensor technology and ambient display capabilities, enhances the traditional game of tag by determining when a valid tag has been made and visualisin

  18. Steering Gameplay Behavior in the Interactive Tag Playground

    NARCIS (Netherlands)

    Van Delden, Robby; Moreno, Alejandro; Poppe, Ronald; Reidsma, Dennis; Heylen, Dirk K J

    2014-01-01

    This paper deals with steering player behavior in the Interactive Tag Playground (ITP). The ITP, an ambient environment instrumented with contact-free sensor technology and ambient display capabilities, enhances the traditional game of tag by determining when a valid tag has been made and visualisin

  19. Analytic Steering: Inserting Context into the Information Dialog

    Energy Technology Data Exchange (ETDEWEB)

    Bohn, Shawn J.; Calapristi, Augustin J.; Brown, Shyretha D.; Nakamura, Grant C.

    2011-10-23

    An analyst’s intrinsic domain knowledge is a primary asset in almost any analysis task. Unstructured text analysis systems that apply un-supervised content analysis approaches can be more effective if they can leverage this domain knowledge in a manner that augments the information discovery process without obfuscating new or unexpected content. Current unsupervised approaches rely upon the prowess of the analyst to submit the right queries or observe generalized document and term relationships from ranked or visual results. We propose a new approach which allows the user to control or steer the analytic view within the unsupervised space. This process is controlled through the data characterization process via user supplied context in the form of a collection of key terms. We show that steering with an appropriate choice of key terms can provide better relevance to the analytic domain and still enable the analyst to uncover un-expected relationships; this paper discusses cases where various analytic steering approaches can provide enhanced analysis results and cases where analytic steering can have a negative impact on the analysis process.

  20. DSPIC BASED POWER ASSISTED STEERING USING BRUSHLESS DIRECT CURRENT MOTOR

    Directory of Open Access Journals (Sweden)

    G. R.P. Lakshmi

    2013-01-01

    Full Text Available This study illustrates the Electrically Assisted power Steering (EAS using BLDC motor for a vehicle. Earlier the Electrically Assisted power Steering (EAS was implemented with DSP. This study shows the usage of a dsPIC to control the BLDC motor with an encoder. The BLDC motor here is driven by dsPIC through a three phase inverter system. IRAMS type of inverter is used which is cost efficient and space efficient. The dsPIC supplied with the input of the steering. In its higher capacity the vehicles speed controller acts as the assistance level controller for steering effort. At the lower capacity, the torque controller gives the effort level control. In reality this can be realized as torque sensor and vehicle sensor interfaced in the dsPIC. For actual implementation in the system, a dsPIC-based BLDC motor controller with three-phase inverter module is used with Hall-effect sensor feedback. It is designed in such a way that the driver assistance can be varied at any time without any difficulty.

  1. Image Processing In Laser-Beam-Steering Subsystem

    Science.gov (United States)

    Lesh, James R.; Ansari, Homayoon; Chen, Chien-Chung; Russell, Donald W.

    1996-01-01

    Conceptual design of image-processing circuitry developed for proposed tracking apparatus described in "Beam-Steering Subsystem For Laser Communication" (NPO-19069). In proposed system, desired frame rate achieved by "windowed" readout scheme in which only pixels containing and surrounding two spots read out and others skipped without being read. Image data processed rapidly and efficiently to achieve high frequency response.

  2. Proportional directional valve based automatic steering system for tractors

    Institute of Scientific and Technical Information of China (English)

    Jin-yi LIU; Jing-quan TAN; En-rong MAO; Zheng-he SONG; Zhong-xiang ZHU‡

    2016-01-01

    Most automatic steering systems for large tractors are designed with hydraulic systems that run on either constant flow or constant pressure. Such designs are limited in adaptability and applicability. Moreover, their control valves can unload in the neutral position and eventually lead to serious hydraulic leakage over long operation periods. In response to the problems noted above, a multifunctional automatic hydraulic steering circuit is presented. The system design is composed of a 5-way-3-position proportional directional valve, two pilot-controlled check valves, a pressure-compensated directional valve, a pressure-compensated flow regulator valve, a load shuttle valve, and a check valve, among other components. It is adaptable to most open-center systems with constant flow supply and closed-center systems with load feedback. The design maintains the lowest pressure under load feedback and stays at the neutral position during unloading, thus meeting the requirements for steering. The steering controller is based on proportional-integral-derivative (PID) running on a 51-microcontroller-unit master control chip. An experimental platform is developed to establish the basic characteristics of the system subject to stepwise inputs and sinusoi-dal tracking. Test results show that the system design demonstrates excellent control accuracy, fast response, and negligible leak during long operation periods.

  3. The value of theoretical multiplicity for steering transitions towards sustainability

    NARCIS (Netherlands)

    Dewulf, A.; Termeer, C.J.A.M.; Pot, W.D.; Werkman, R.A.; Breeman, G.E.

    2009-01-01

    Transition management, as a theory of directing structural societal changes towards sustainable system innovations, has become a major topic in scientific research over the last years. In this paper we focus on the question how transitions towards sustainability can be steered, governed or managed,

  4. Mechanics of Flexible Needles Robotically Steered through Soft Tissue

    NARCIS (Netherlands)

    Misra, S.; Reed, K.B.; Schafer, B.W.; Ramesh, K.T.; Okamura, A.M.

    2010-01-01

    The tip asymmetry of a bevel-tip needle results in the needle naturally bending when it is inserted into soft tissue. This enables robotic needle steering, which can be used in medical procedures to reach subsurface targets inaccessible by straight-line trajectories. However, accurate path planning

  5. Cancer

    Science.gov (United States)

    Cancer begins in your cells, which are the building blocks of your body. Normally, your body forms ... be benign or malignant. Benign tumors aren't cancer while malignant ones are. Cells from malignant tumors ...

  6. Redox-mediated bypass of restriction point via skipping of G1pm

    Directory of Open Access Journals (Sweden)

    Greene James J

    2006-07-01

    Full Text Available Abstract Background It is well known that cancer cells bypass the restriction point, R, and undergo uncontrolled cell proliferation. Hypothesis and evidence We suggest here that fibrosarcoma cells enter G1ps directly from M, skipping G1pm, hence bypassing R, in response to redox modulation. Evidence is presented from the published literature that demonstrate a shortening of the cycle period of transformed fibroblasts (SV-3T3 compared to the nontransformed 3T3 fibroblasts, corresponding to the duration of G1pm in the 3T3 fibroblasts. Evidence is also presented that demonstrate that redox modulation can induce the CUA-4 fibroblasts to bypass R, resulting in a cycle period closely corresponding to the cycle period of fibrosarcoma cells (HT1080. Conclusion The evidence supports our hypothesis that a low internal redox potential can cause fibrosarcoma cells to skip the G1pm phase of the cell cycle.

  7. Redox potential tuning by redox-inactive cations in nature's water oxidizing catalyst and synthetic analogues.

    Science.gov (United States)

    Krewald, Vera; Neese, Frank; Pantazis, Dimitrios A

    2016-04-28

    The redox potential of synthetic oligonuclear transition metal complexes has been shown to correlate with the Lewis acidity of a redox-inactive cation connected to the redox-active transition metals of the cluster via oxo or hydroxo bridges. Such heterometallic clusters are important cofactors in many metalloenzymes, where it is speculated that the redox-inactive constituent ion of the cluster serves to optimize its redox potential for electron transfer or catalysis. A principal example is the oxygen-evolving complex in photosystem II of natural photosynthesis, a Mn4CaO5 cofactor that oxidizes water into dioxygen, protons and electrons. Calcium is critical for catalytic function, but its precise role is not yet established. In analogy to synthetic complexes it has been suggested that Ca(2+) fine-tunes the redox potential of the manganese cluster. Here we evaluate this hypothesis by computing the relative redox potentials of substituted derivatives of the oxygen-evolving complex with the cations Sr(2+), Gd(3+), Cd(2+), Zn(2+), Mg(2+), Sc(3+), Na(+) and Y(3+) for two sequential transitions of its catalytic cycle. The theoretical approach is validated with a series of experimentally well-characterized Mn3AO4 cubane complexes that are structural mimics of the enzymatic cluster. Our results reproduce perfectly the experimentally observed correlation between the redox potential and the Lewis acidities of redox-inactive cations for the synthetic complexes. However, it is conclusively demonstrated that this correlation does not hold for the oxygen evolving complex. In the enzyme the redox potential of the cluster only responds to the charge of the redox-inactive cations and remains otherwise insensitive to their precise identity, precluding redox-tuning of the metal cluster as a primary role for Ca(2+) in biological water oxidation.

  8. Periodic Exposure of Keratinocytes to Cold Physical Plasma: An In Vitro Model for Redox-Related Diseases of the Skin

    Directory of Open Access Journals (Sweden)

    Anke Schmidt

    2016-01-01

    Full Text Available Oxidative stress illustrates an imbalance between radical formation and removal. Frequent redox stress is critically involved in many human pathologies including cancer, psoriasis, and chronic wounds. However, reactive species pursue a dual role being involved in signaling on the one hand and oxidative damage on the other. Using a HaCaT keratinocyte cell culture model, we investigated redox regulation and inflammation to periodic, low-dose oxidative stress after two, six, eight, ten, and twelve weeks. Chronic redox stress was generated by recurrent incubation with cold physical plasma-treated cell culture medium. Using transcriptome microarray technology, we identified both acute ROS-stress responses as well as numerous adaptions after several weeks of redox challenge. We determined a differential expression (2-fold, FDR < 0.01, p<0.05 of 260 genes that function in inflammation and redox homeostasis, such as cytokines (e.g., IL-6, IL-8, and IL-10, growth factors (e.g., CSF2, FGF, and IGF-2, and antioxidant enzymes (e.g., HMOX, NQO1, GPX, and PRDX. Apoptotic signaling was affected rather modestly, especially in p53 downstream targets (e.g., BCL2, BBC3, and GADD45. Strikingly, the cell-protective heat shock protein HSP27 was strongly upregulated (p<0.001. These results suggested cellular adaptions to frequent redox stress and may help to better understand the inflammatory responses in redox-related diseases.

  9. Study on a New Steering Mechanism for Point-the-Bit Rotary Steerable System

    Directory of Open Access Journals (Sweden)

    Yuanzhi Li

    2014-02-01

    Full Text Available This paper presents a novel steering mechanism embedded in a point-the-bit rotary steerable system (RSS for oilfield exploitation. The new steering mechanism adopts a set of universal joints to alleviate the high alternative strain on drilling mandrel and employs a specially designed planetary gear small tooth number difference (PGSTD to achieve directional steering. Its principle and characteristics are explained and examined through a series of analyses. First, the eccentric displacement vector of the offset point on the drilling mandrel is formulated and kinematic solutions are established. Next, structural design for the new steering mechanism is addressed. Then, procedures and program architectures for simulating offset state of the drilling mandrel and motion trajectory of the whole steering mechanism are presented. After that, steering motion simulations of the new steering mechanism for both 2D and 3D well trajectories are then performed by combining LabVIEW and SolidWorks. Finally, experiments on the steering motion control of the new steering mechanism prototype are carried out. The simulations and experiments reveal that the steering performance of the new steering mechanism is satisfied. The research can provide good guidance for further research and engineering application of the point-the-bit RSS.

  10. Novel Redox Processes for Carbonaceous Fuel Conversion

    Science.gov (United States)

    He, Feng

    The current study investigates oxygen carrier development, process intensification, and oxygen carrier attrition behaviors for a number of novel, redox-based energy conversion schemes. (Abstract shortened by ProQuest.).

  11. Assessment of redox markers in cattle

    OpenAIRE

    Burke, Nathaniel Caleb

    2007-01-01

    Metabolic redox status may have important implications to cattle health and production. Antioxidants and biomarkers of oxidative stress were evaluated in cattle under three phases of management. Each phase stood alone as a treatment model, and managerial aspects during the phase were evaluated as potential moderators of redox balance. Yearling heifers were used to assess the impact of fescue toxicosis and heat stress on selected markers in study 1. Intravaginal temperatures, ADG, serum prolac...

  12. Development of active rear steer actuator. Development of four wheel steer actuator for active safety; Active rear steer actuator no kaihatsu. Yobo anzen ni muketa 4WS actuator no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Yamanaka, T. [Aisin Seiki Co. Ltd., Aichi (Japan)

    1997-10-01

    Recently, ecology, energy saving and safety have become important issues. And Active Safety is spotlighted in vehicle control area. Many researches and developments on four wheel steer system have been done to improve vehicle stability. We have developed the Active Rear Steer system with electromechanical Actuator, which is mass-productive, compact, and high response and durable. 10 figs., 5 tabs.

  13. Membranes for Redox Flow Battery Applications

    Directory of Open Access Journals (Sweden)

    Maria Skyllas-Kazacos

    2012-06-01

    Full Text Available The need for large scale energy storage has become a priority to integrate renewable energy sources into the electricity grid. Redox flow batteries are considered the best option to store electricity from medium to large scale applications. However, the current high cost of redox flow batteries impedes the wide spread adoption of this technology. The membrane is a critical component of redox flow batteries as it determines the performance as well as the economic viability of the batteries. The membrane acts as a separator to prevent cross-mixing of the positive and negative electrolytes, while still allowing the transport of ions to complete the circuit during the passage of current. An ideal membrane should have high ionic conductivity, low water intake and excellent chemical and thermal stability as well as good ionic exchange capacity. Developing a low cost, chemically stable membrane for redox flow cell batteries has been a major focus for many groups around the world in recent years. This paper reviews the research work on membranes for redox flow batteries, in particular for the all-vanadium redox flow battery which has received the most attention.

  14. Membranes for redox flow battery applications.

    Science.gov (United States)

    Prifti, Helen; Parasuraman, Aishwarya; Winardi, Suminto; Lim, Tuti Mariana; Skyllas-Kazacos, Maria

    2012-06-19

    The need for large scale energy storage has become a priority to integrate renewable energy sources into the electricity grid. Redox flow batteries are considered the best option to store electricity from medium to large scale applications. However, the current high cost of redox flow batteries impedes the wide spread adoption of this technology. The membrane is a critical component of redox flow batteries as it determines the performance as well as the economic viability of the batteries. The membrane acts as a separator to prevent cross-mixing of the positive and negative electrolytes, while still allowing the transport of ions to complete the circuit during the passage of current. An ideal membrane should have high ionic conductivity, low water intake and excellent chemical and thermal stability as well as good ionic exchange capacity. Developing a low cost, chemically stable membrane for redox flow cell batteries has been a major focus for many groups around the world in recent years. This paper reviews the research work on membranes for redox flow batteries, in particular for the all-vanadium redox flow battery which has received the most attention.

  15. Role of glutathione, glutathione transferase, and glutaredoxin in regulation of redox-dependent processes.

    Science.gov (United States)

    Kalinina, E V; Chernov, N N; Novichkova, M D

    2014-12-01

    Over the last decade fundamentally new features have been revealed for the participation of glutathione and glutathione-dependent enzymes (glutathione transferase and glutaredoxin) in cell proliferation, apoptosis, protein folding, and cell signaling. Reduced glutathione (GSH) plays an important role in maintaining cellular redox status by participating in thiol-disulfide exchange, which regulates a number of cell functions including gene expression and the activity of individual enzymes and enzyme systems. Maintaining optimum GSH/GSSG ratio is essential to cell viability. Decrease in the ratio can serve as an indicator of damage to the cell redox status and of changes in redox-dependent gene regulation. Disturbance of intracellular GSH balance is observed in a number of pathologies including cancer. Consequences of inappropriate GSH/GSSG ratio include significant changes in the mechanism of cellular redox-dependent signaling controlled both nonenzymatically and enzymatically with the participation of isoforms of glutathione transferase and glutaredoxin. This review summarizes recent data on the role of glutathione, glutathione transferase, and glutaredoxin in the regulation of cellular redox-dependent processes.

  16. Cobalt and marine redox evolution

    Science.gov (United States)

    Swanner, Elizabeth D.; Planavsky, Noah J.; Lalonde, Stefan V.; Robbins, Leslie J.; Bekker, Andrey; Rouxel, Olivier J.; Saito, Mak A.; Kappler, Andreas; Mojzsis, Stephen J.; Konhauser, Kurt O.

    2014-03-01

    Cobalt (Co) is a bio-essential trace element and limiting nutrient in some regions of the modern oceans. It has been proposed that Co was more abundant in poorly ventilated Precambrian oceans based on the greater utilization of Co by anaerobic microbes relative to plants and animals. However, there are few empirical or theoretical constraints on the history of seawater Co concentrations. Herein, we present a survey of authigenic Co in marine sediments (iron formations, authigenic pyrite and bulk euxinic shales) with the goal of tracking changes in the marine Co reservoir throughout Earth's history. We further provide an overview of the modern marine Co cycle, which we use as a platform to evaluate how changes in the redox state of Earth's surface were likely to have affected marine Co concentrations. Based on sedimentary Co contents and our understanding of marine Co sources and sinks, we propose that from ca. 2.8 to 1.8 Ga the large volume of hydrothermal fluids circulating through abundant submarine ultramafic rocks along with a predominantly anoxic ocean with a low capacity for Co burial resulted in a large dissolved marine Co reservoir. We tentatively propose that there was a decrease in marine Co concentrations after ca. 1.8 Ga resulting from waning hydrothermal Co sources and the expansion of sulfide Co burial flux. Changes in the Co reservoir due to deep-water ventilation in the Neoproterozoic, if they occurred, are not resolvable with the current dataset. Rather, Co enrichments in Phanerozoic euxinic shales deposited during ocean anoxic events (OAE) indicate Co mobilization from expanded anoxic sediments and enhanced hydrothermal sources. A new record of marine Co concentrations provides a platform from which we can reevaluate the role that environmental Co concentrations played in shaping biological Co utilization throughout Earth's history.

  17. Steering of Educational Processes in a Digital Medium Environment

    DEFF Research Database (Denmark)

    Tække, Jesper; Paulsen, Michael

    2015-01-01

    This paper is about challenges to steering and leadership of educational interaction in classrooms provided by the new medium environment that comes with digital media. In the new medium environment, the old way of steering what is going on in the classroom appears not to work since...... it was developed in the image of the industrial society and based on a closed classroom. Now with the digital media and wireless networks the classroom is opened and the old way of organizing teaching has become inadequate: The students are disturbed by the new media, instead of learning through them. Inspired...... by systems theory we outline a more adequate way of teaching in the new medium environment – a teaching that can manage the new situation and use the new possibilities provided by the digital media. The argumentation builds on empirical findings from the action research project Socio Media Education (SME...

  18. Detailed field test of yaw-based wake steering

    Science.gov (United States)

    Fleming, P.; Churchfield, M.; Scholbrock, A.; Clifton, A.; Schreck, S.; Johnson, K.; Wright, A.; Gebraad, P.; Annoni, J.; Naughton, B.; Berg, J.; Herges, T.; White, J.; Mikkelsen, T.; Sjöholm, M.; Angelou, N.

    2016-09-01

    This paper describes a detailed field-test campaign to investigate yaw-based wake steering. In yaw-based wake steering, an upstream turbine intentionally misaligns its yaw with respect to the inflow to deflect its wake away from a downstream turbine, with the goal of increasing total power production. In the first phase, a nacelle-mounted scanning lidar was used to verify wake deflection of a misaligned turbine and calibrate wake deflection models. In the second phase, these models were used within a yaw controller to achieve a desired wake deflection. This paper details the experimental design and setup. All data collected as part of this field experiment will be archived and made available to the public via the U.S. Department of Energy's Atmosphere to Electrons Data Archive and Portal.

  19. Mechanics of Thin Strip Steering in Hot Rolling

    Science.gov (United States)

    Jiang, Zhengyi; Tieu, Kiet A.

    2004-06-01

    The hot rolling of thin strip can result in several problems in hot rolling, for instance, the control of strip steering, strip shape and flatness and surface roughness etc. Therefore, the hot rolling of thin strip brings out a requirement of innovative technologies such as the extended control of shape and flatness, steering control and reduction of load by roll gap lubrication. In this paper, the authors focus on the analysis of thin strip snaking movement, as well as solve the related problems such as the shape and flatness due to a larger reduction applied when the strip is thinner. A finite element method was used to simulate this nonsymmetricity rolling considering the non-uniform reduction along the strip width. The calculated spread is compared with the measured values obtained from the rolling mill in laboratory and the friction effect is also discussed.

  20. Steering of Educational Processes in a Digital Medium Environment

    DEFF Research Database (Denmark)

    Tække, Jesper; Paulsen, Michael Eric

    2016-01-01

    it was developed in the image of the industrial society and based on a closed classroom. Now with the digital media and wireless networks the classroom is opened and the old way of organizing teaching has become inadequate: The students are disturbed by the new media, instead of learning through them. Inspired......This paper is about challenges to steering and leadership of educational interaction in classrooms provided by the new medium environment that comes with digital media. In the new medium environment, the old way of steering what is going on in the classroom appears not to work since...... by systems theory we outline a more adequate way of teaching in the new medium environment – a teaching that can manage the new situation and use the new possibilities provided by the digital media. The argumentation builds on empirical findings from the action research project Socio Media Education (SME...

  1. Robust autopilot with wave filter for ship steering

    Institute of Scientific and Technical Information of China (English)

    WANG Xian-zhou; XU Han-zhen

    2006-01-01

    Research was done to overcome traditional problems associated with automatic steering systems of a ship in a seaway. A ship's dynamic model with wave disturbances was built and a wave filter was designed by means of an extended states observer (ESO). The model estimated the low frequency motion component from a heading measurement corrupted by colorednoise, so back-and-forth steering caused by high frequency wave disturbances was avoided. At the same time, a robust autopilot system,designed by variable structure control theory, was presented. Simulation results achieved in dangerous sea status show that the wave filter works very well and the autopilot has strong robustness to environmental disturbances and model perturbation, and more importantly, the frequency of rudder adjustments is reduced noticeably.

  2. Redox interplay between mitochondria and peroxisomes

    Directory of Open Access Journals (Sweden)

    Celien eLismont

    2015-05-01

    Full Text Available Reduction-oxidation or ‘redox’ reactions are an integral part of a broad range of cellular processes such as gene expression, energy metabolism, protein import and folding, and autophagy. As many of these processes are intimately linked with cell fate decisions, transient or chronic changes in cellular redox equilibrium are likely to contribute to the initiation and progression of a plethora of human diseases. Since a long time, it is known that mitochondria are major players in redox regulation and signaling. More recently, it has become clear that also peroxisomes have the capacity to impact redox-linked physiological processes. To serve this function, peroxisomes cooperate with other organelles, including mitochondria. This review provides a comprehensive picture of what is currently known about the redox interplay between mitochondria and peroxisomes in mammals. We first outline the pro- and antioxidant systems of both organelles and how they may function as redox signaling nodes. Next, we critically review and discuss emerging evidence that peroxisomes and mitochondria share an intricate redox-sensitive relationship and cooperate in cell fate decisions. Key issues include possible physiological roles, messengers, and mechanisms. We also provide examples of how data mining of publicly-available datasets from ‘omics’ technologies can be a powerful means to gain additional insights into potential redox signaling pathways between peroxisomes and mitochondria. Finally, we highlight the need for more studies that seek to clarify the mechanisms of how mitochondria may act as dynamic receivers, integrators, and transmitters of peroxisome-derived mediators of oxidative stress. The outcome of such studies may open up exciting new avenues for the community of researchers working on cellular responses to organelle-derived oxidative stress, a research field in which the role of peroxisomes is currently highly underestimated and an issue of

  3. Quadrupole Law and Steering Options in the Linac4 DTL

    CERN Document Server

    Stovall, J

    2009-01-01

    The Linac4 drift-tube linac (DTL) reference design has been modified to reduce the power consumption in tank 1 by adjusting the accelerating field and phase laws. In this note we investigate three options for the transverse focusing lattice, quadrupole law, and two options for beam steering. We use acceptance, sensitivity to alignment errors and the probabiity of beam loss as figures of merit for evaluating each option.

  4. Low-Absorption Liquid Crystals for Infrared Beam Steering

    Science.gov (United States)

    2015-09-30

    absorption coefficient and d is the LC layer thickness . Let us take a~!0/cm as an example. For a 10-|j,m- thick LC layer, ad=0.01 and the transmittance...remains 99%. However, if the LC layer thickness (or effective optical path length) increases, then the absorption will increase exponentially, as Eq. (1...weight-and-power, 2) increasing mean-time-between- failure, and 3) reducing system complexity. Beam steering based on liquid crystal ( LC ) optical phase

  5. Planning analysis and political steering with New Public Management

    DEFF Research Database (Denmark)

    Sager, Tore Øivin; Sørensen, Claus Hedegaard

    2011-01-01

    of interviews sheds light on the apparent paradox that parliamentarians accept delegation of highway investment decisions despite their profound scepticism to the cost-benefit analyses and impact calculations that are essential to management by objectives and results, which was to give them continued political...... by the Government. The political concentration on strategic steering, the concomitant delegation, and management by objectives and results are central components of New Public Management....

  6. Thiol switches in redox regulation of chloroplasts: balancing redox state, metabolism and oxidative stress.

    Science.gov (United States)

    Dietz, Karl-Josef; Hell, Rüdiger

    2015-05-01

    In photosynthesizing chloroplasts, rapidly changing energy input, intermediate generation of strong reductants as well as oxidants and multiple participating physicochemical processes and pathways, call for efficient regulation. Coupling redox information to protein function via thiol modifications offers a powerful mechanism to activate, down-regulate and coordinate interdependent processes. Efficient thiol switching of target proteins involves the thiol-disulfide redox regulatory network, which is highly elaborated in chloroplasts. This review addresses the features of this network. Its conditional function depends on specificity of reduction and oxidation reactions and pathways, thiol redox buffering, but also formation of heterogeneous milieus by microdomains, metabolite gradients and macromolecular assemblies. One major player is glutathione. Its synthesis and function is under feedback redox control. The number of thiol-controlled processes and involved thiol switched proteins is steadily increasing, e.g., in tetrapyrrole biosynthesis, plastid transcription and plastid translation. Thus chloroplasts utilize an intricate and versatile redox regulatory network for intraorganellar and retrograde communication.

  7. Hydrogen peroxide regulates cell adhesion through the redox sensor RPSA.

    Science.gov (United States)

    Vilas-Boas, Filipe; Bagulho, Ana; Tenente, Rita; Teixeira, Vitor H; Martins, Gabriel; da Costa, Gonçalo; Jerónimo, Ana; Cordeiro, Carlos; Machuqueiro, Miguel; Real, Carla

    2016-01-01

    To become metastatic, a tumor cell must acquire new adhesion properties that allow migration into the surrounding connective tissue, transmigration across endothelial cells to reach the blood stream and, at the site of metastasis, adhesion to endothelial cells and transmigration to colonize a new tissue. Hydrogen peroxide (H2O2) is a redox signaling molecule produced in tumor cell microenvironment with high relevance for tumor development. However, the molecular mechanisms regulated by H2O2 in tumor cells are still poorly known. The identification of H2O2-target proteins in tumor cells and the understanding of their role in tumor cell adhesion are essential for the development of novel redox-based therapies for cancer. In this paper, we identified Ribosomal Protein SA (RPSA) as a target of H2O2 and showed that RPSA in the oxidized state accumulates in clusters that contain specific adhesion molecules. Furthermore, we showed that RPSA oxidation improves cell adhesion efficiency to laminin in vitro and promotes cell extravasation in vivo. Our results unravel a new mechanism for H2O2-dependent modulation of cell adhesion properties and identify RPSA as the H2O2 sensor in this process. This work indicates that high levels of RPSA expression might confer a selective advantage to tumor cells in an oxidative environment.

  8. Optimization of Steering Elements in the RIA Driver Linac

    CERN Document Server

    SchnirmanLessner, Eliane; Ostroumov, Peter

    2005-01-01

    The driver linac of the projected RIA facility is a versatile accelerator, a 1.4-GV, CW superconducting linac designed to simultaneously accelerate several heavy-ion charge states, providing beams from protons at about 1 GeV to uranium at 400 MeV/u at power levels at a minimum of 100 kW and up to 400 kW for most beams. Acceleration of multiple-charge-state uranium beams places stringent requirements on the linac design. A steering algorithm was derived that fulfilled the driver’s real estate requirements, such as placement of steering dipole coils on SC solenoids and of beam position monitors outside cryostats, and beam-dynamics requirements, such as coupling effects induced by the focusing solenoids.* The algorithm has been fully integrated in the tracking code TRACK** and is used to study and optimize the number and position of steering elements that minimize the multiple-beam centroid oscillations and preserve the beam emittance under misalignments of accelerating and transverse focusing elements...

  9. Volume monogamy of quantum steering ellipsoids for multiqubit systems

    Science.gov (United States)

    Cheng, Shuming; Milne, Antony; Hall, Michael J. W.; Wiseman, Howard M.

    2016-10-01

    The quantum steering ellipsoid can be used to visualize 2-qubit states, and thus provides a generalization of the Bloch picture for the single qubit. Recently, a monogamy relation for the volumes of steering ellipsoids has been derived for pure 3-qubit states and shown to be stronger than the celebrated Coffman-Kundu-Wootters inequality. We first demonstrate the close connection between this volume monogamy relation and the classification of pure 3-qubit states under stochastic local operations and classical communication. We then show that this monogamy relation does not hold for general mixed 3-qubit states and derive a weaker monogamy relation that does hold for such states. We also prove a volume monogamy relation for pure 4-qubit states (further conjectured to hold for the mixed case), and generalize our 3-qubit inequality to n qubits. Finally, we study the effect of noise on the quantum steering ellipsoid and find that the volume of any 2-qubit state is nonincreasing when the state is exposed to arbitrary local noise. This implies that any volume monogamy relation for a given class of multiqubit states remains valid under the addition of local noise. We investigate this quantitatively for the experimentally relevant example of isotropic noise.

  10. Erasmus Darwin's improved design for steering carriages and cars.

    Science.gov (United States)

    King-Hele, Desmond

    2002-01-01

    Carriage journeys in England during the eighteenth century were notoriously dangerous. Rutted and pot-holed roads exacerbated the deficiencies in steering, springing and stability. In 1758 the young Dr. Erasmus Darwin (1731-1802; F. R. S. 1761) was travelling about 10,000 miles a year in visits to patients from his house at Lichfield. To alleviate the danger and discomfort of his journey, he developed a design for improved carriage steering and stability, which he road-tested over 20,000 miles on two carriages. In 1765 Richard Lovell Edgeworth (1744-1817; F. R. S. 1718) heard about Darwin's design, urged the Society of Arts to enquire about it, and then visited Darwin himself. With the aid of manuscripts from the Archive of the Royal Society of Arts and elsewhere, I offer a reconstruction of Darwin's improved method of steering, which relies on four jointed rods, initially in the form of an isosceles trapezium. The mechanism was reinvented more than 50 years later, and came to be used widely in early modern cars.

  11. Imperfection Insensitivity Analyses of Advanced Composite Tow-Steered Shells

    Science.gov (United States)

    Wu, K. Chauncey; Farrokh, Babak; Stanford, Bret K.; Weaver, Paul M.

    2016-01-01

    Two advanced composite tow-steered shells, one with tow overlaps and another without overlaps, were previously designed, fabricated and tested in end compression, both without cutouts, and with small and large cutouts. In each case, good agreement was observed between experimental buckling loads and supporting linear bifurcation buckling analyses. However, previous buckling tests and analyses have shown historically poor correlation, perhaps due to the presence of geometric imperfections that serve as failure initiators. For the tow-steered shells, their circumferential variation in axial stiffness may have suppressed this sensitivity to imperfections, leading to the agreement noted between tests and analyses. To investigate this further, a numerical investigation was performed in this study using geometric imperfections measured from both shells. Finite element models of both shells were analyzed first without, and then, with measured imperfections that were then, superposed in different orientations around the shell longitudinal axis. Small variations in both the axial prebuckling stiffness and global buckling load were observed for the range of imperfections studied here, which suggests that the tow steering, and resulting circumferentially varying axial stiffness, may result in the test-analysis correlation observed for these shells.

  12. PERFORMANCE ANALYSIS OF AZIMUTH ELECTRONIC BEAM STEERING MODE SPACEBORNE SAR

    Institute of Scientific and Technical Information of China (English)

    Han Xiaodong; Xu Wei; Han Xiaolei

    2013-01-01

    Pointing angle and pattern of the antenna can be changed swiftly to actualize the azimuth beam scanning by using electronic beam steering,which makes the Synthetic Aperture Radar (SAR)system more flexible and achieve a high resolution or cover a long strip within short time span.When the pointing angle is steered away from boresight,some aberrations may appear on the antenna pattern,e.g.,the grating lobe appears,the main lobe gain decrease,and antenna pattern broadens,e.g.,the aberrations result in the worsening of system performance,and complicate the corresponding performance analysis method.Conventional computation methods of performance parameters do not account for the rapid change of the antenna pattern.It introduces remarkable errors when the scanning angle is large.In this paper,a method of calculating performance parameters is proposed for the beam steering mode,which achieves the parameters by the energy accumulation in time domain.Actually,the proposed method simulates the working process of SAR and obtains accurate performance parameters.Furthermore,we analyze the effects of the grating lobe on the Azimuth Ambiguity to Signal Ratio (AASR),and present the generic Pulse Repetition Frequency (PRF) choosing principle which can also prevent the ambiguous area from weighting by the grating lobe.Finally,the effect of the antenna configuration on the performance parameters is analyzed by a system example.

  13. DCP's Early Detection Research Guides Future Science | Division of Cancer Prevention

    Science.gov (United States)

    Early detection research funded by the NCI's Division of Cancer Prevention has positively steered both public health and clinical outcomes, and set the stage for findings in the next generation of research. |

  14. Postweaning performance and carcass merit of F1 steers sired by Brahman and alternative subtropically adapted breeds.

    Science.gov (United States)

    Franke, D E

    1997-10-01

    Comparisons were made among F1 steers sired by Brahman and alternative subtropically adapted breeds of bulls for feedlot and carcass traits when steers were produced from Angus- and Hereford-type dams. Brahman-derivative breeds included Brangus, Beefmaster, and Santa Gertrudis. Brangus- and Beefmaster-sired steers weighed less at slaughter, whereas carcasses of Brangus- and Santa Gertrudis-sired steers had more marbling than those of Brahman-sired steers. Brahman-sired steer carcasses had greater longissimus muscle area than carcasses of Santa Gertrudis-sired steers. Other Zebu breeds compared to Brahman were Boran, Gir, Indu-Brazil, Nellore, Red Brahman, and Sahiwal. Steers by Brahman sires had higher slaughter weights than steers by Boran, Gir, Nellore, or Sahiwal sires. Hot carcass weights of Brahman-sired steers were also higher than those of Boran- and Sahiwal-sired steers. Steer carcasses by Brahman sires had greater longissimus muscle area than those of steers by Sahiwal sires. Non-Zebu breeds included Tuli and Senepol. Steers by Tuli sires grew slower, had lower slaughter weights, and their carcasses weighed less than those of Brahman-sired steers. Brahman-sired steer carcasses had greater longissimus muscle area but less marbling than carcasses of Tuli-sired steers. These data suggest that steers by Brahman sires have an advantage for slaughter weight over steers by Brangus, Beefmaster, Boran, Gir, Nellore, Sahiwal, and Tuli sires, but their carcasses are at a disadvantage for marbling score compared with those by Brangus, Boran, Nellore, and Tuli sires.

  15. Altered Glutathione Redox State in Schizophrenia

    Directory of Open Access Journals (Sweden)

    Jeffrey K. Yao

    2006-01-01

    Full Text Available Altered antioxidant status has been reported in schizophrenia. The glutathione (GSH redox system is important for reducing oxidative stress. GSH, a radical scavenger, is converted to oxidized glutathione (GSSG through glutathione peroxidase (GPx, and converted back to GSH by glutathione reductase (GR. Measurements of GSH, GSSG and its related enzymatic reactions are thus important for evaluating the redox and antioxidant status. In the present study, levels of GSH, GSSG, GPx and GR were assessed in the caudate region of postmortem brains from schizophrenic patients and control subjects (with and without other psychiatric disorders. Significantly lower levels of GSH, GPx, and GR were found in schizophrenic group than in control groups without any psychiatric disorders. Concomitantly, a decreased GSH:GSSG ratio was also found in schizophrenic group. Moreover, both GSSG and GR levels were significantly and inversely correlated to age of schizophrenic patients, but not control subjects. No significant differences were found in any GSH redox measures between control subjects and individuals with other types of psychiatric disorders. There were, however, positive correlations between GSH and GPx, GSH and GR, as well as GPx and GR levels in control subjects without psychiatric disorders. These positive correlations suggest a dynamic state is kept in check during the redox coupling under normal conditions. By contrast, lack of such correlations in schizophrenia point to a disturbance of redox coupling mechanisms in the antioxidant defense system, possibly resulting from a decreased level of GSH as well as age-related decreases of GSSG and GR activities.

  16. Redox regulation of protein damage in plasma.

    Science.gov (United States)

    Griffiths, Helen R; Dias, Irundika H K; Willetts, Rachel S; Devitt, Andrew

    2014-01-01

    The presence and concentrations of modified proteins circulating in plasma depend on rates of protein synthesis, modification and clearance. In early studies, the proteins most frequently analysed for damage were those which were more abundant in plasma (e.g. albumin and immunoglobulins) which exist at up to 10 orders of magnitude higher concentrations than other plasma proteins e.g. cytokines. However, advances in analytical techniques using mass spectrometry and immuno-affinity purification methods, have facilitated analysis of less abundant, modified proteins and the nature of modifications at specific sites is now being characterised. The damaging reactive species that cause protein modifications in plasma principally arise from reactive oxygen species (ROS) produced by NADPH oxidases (NOX), nitric oxide synthases (NOS) and oxygenase activities; reactive nitrogen species (RNS) from myeloperoxidase (MPO) and NOS activities; and hypochlorous acid from MPO. Secondary damage to proteins may be caused by oxidized lipids and glucose autooxidation. In this review, we focus on redox regulatory control of those enzymes and processes which control protein maturation during synthesis, produce reactive species, repair and remove damaged plasma proteins. We have highlighted the potential for alterations in the extracellular redox compartment to regulate intracellular redox state and, conversely, for intracellular oxidative stress to alter the cellular secretome and composition of extracellular vesicles. Through secreted, redox-active regulatory molecules, changes in redox state may be transmitted to distant sites.

  17. Data transfer through beam steering using agile lensing

    Science.gov (United States)

    Arshad, Muhammad Assad; Reza, Syed Azer; Muhammad, Ahsan

    2016-04-01

    This paper presents a data transfer scheme using multi-focus tunable lenses. The design involves the use of a standard laser source and a variable focus agile lens to steer to the laser beam that passes through the lens. In our proposed system, the beam steer angle depends on an input electrical signal which drives the tunable lens. Therefore the beam steer angle is made to follow the variations in the input electrical drive signal. This is extremely interesting for data transfer applications as the data signal can be used as the input drive signal to the lens. The laser beam is steered according to the input data voltage levels and when the beam is incident on a photo-detector of a finite size, only a fraction of its total incident optical power is received by the photo-detector. This power contribution is proportional to the fraction of the total number of photons per unit area which are incident on the active area of the detector. The remaining photons which are not incident on the photo-detector do not contribute to the received power at the photo-detector. We present the theory of beam steering through a tunable lens and present a theoretical framework which governs data transfer through the proposed method. We also present the transfer function of the proposed system which helps us to calculate its essential theoretical performance parameters such as modulation depth and bit error rates. We also present experimental results to demonstrate efficient data transfer through the proposed method. As tunable lenses are primarily deployed in motion-free multi-focus cameras hence most of the modern portable devices such as cellphones and tablets use these lenses to operate the in-built variable focus cameras that are part of these devices. Because tunable lenses are commonly present in several different portable devices, the proposed method of data transfer between two devices is highly promising as it expands the use of the already deployed tunable lenses with

  18. Multiobjective Optimization of Steering Mechanism for Rotary Steering System Using Modified NSGA-II and Fuzzy Set Theory

    Directory of Open Access Journals (Sweden)

    Hongtao Li

    2015-01-01

    Full Text Available Due to the complicated design process of gear train, optimization is a significant approach to improve design efficiency. However, the design of gear train is a complex multiobjective optimization with mixed continuous-discrete variables under numerous nonlinear constraints, and conventional optimization algorithms are not suitable to deal with such optimization problems. In this paper, based on the established dynamic model of steering mechanism for rotary steering system, the key component of which is a planetary gear set with teeth number difference, the optimization problem of steering mechanism is formulated to achieve minimum dynamic responses and outer diameter by optimizing structural parameters under geometric, kinematic, and strength constraints. An optimization procedure based on modified NSGA-II by incorporating dynamic crowding distance strategies and fuzzy set theory is applied to the multiobjective optimization. For comparative purpose, NSGA-II is also employed to obtain Pareto optimal set, and dynamic responses of original and optimized designs are compared. The results show the optimized design has better dynamic responses with minimum outer diameter and the response decay decreases faster. The optimization procedure is feasible to the design of gear train, and this study can provide guidance for designer at the preliminary design phase of mechanical structures with gear train.

  19. Robust Adaptive Beamforming Based on Steering Vector Estimation via Semidefinite Programming Relaxation

    CERN Document Server

    Khabbazibasmenj, Arash; Hassanien, Aboulnasr

    2010-01-01

    We develop a new approach to robust adaptive beamforming in the presence of signal steering vector errors. Since the signal steering vector is known imprecisely, its presumed (prior) value is used to find a more accurate estimate of the actual steering vector, which then is used for obtaining the optimal beamforming weight vector. The objective for finding such an estimate of the actual signal steering vector is the maximization of the beamformer output power, while the constraints are the normalization condition and the requirement that the estimate of the steering vector does not converge to an interference steering vector. Our objective and constraints are free of any design parameters of non-unique choice. The resulting optimization problem is a non-convex quadratically constrained quadratic program, which is NP hard in general. However, for our problem we show that an efficient solution can be found using the semi-definite relaxation technique. Moreover, the strong duality holds for the proposed problem ...

  20. Electronic differential control of 2WD electric vehicle considering steering stability

    Science.gov (United States)

    Hua, Yiding; Jiang, Haobin; Geng, Guoqing

    2017-03-01

    Aiming at the steering wheel differential steering control technology of rear wheel independent driving electric wheel, considering the assisting effect of electronic differential control on vehicle steering, based on the high speed steering characteristic of electric wheel car, the electronic differential speed of auxiliary wheel steering is also studied. A yaw moment control strategy is applied to the vehicle at high speed. Based on the vehicle stability reference value, yaw rate is used to design the fuzzy controller to distribute the driving wheel torque. The simulation results show that the basic electronic differential speed function is realized based on the yaw moment control strategy, while the vehicle stability control is improved and the driving safety is enhanced. On the other hand, the torque control strategy can also assist steering of vehicle.

  1. 脱嘌呤/脱嘧啶核酸内切酶/氧化还原因子-1基因与乳腺癌细胞对吉西他滨耐药的相关性研究%Relationship on chemoresistance between the apurinic/apyrimidinic endonuclease/redox factor-1 in breast cancer with induction of gemcitabine

    Institute of Scientific and Technical Information of China (English)

    郑敏; 曹永晋; 蔡伟华

    2015-01-01

    Objective To investigate the changes of apurinic/apyrimidi-nic endonuclease/redox factor -1 ( APE/Ref -1 ) expression in human breast cancer cell line MCF -7 after induction of gemcitabine and to study the effects of gemcitabine on chemoresistance in breast cancer . Methods After human breast cancer cell line MCF -7 was incubated with 50 nmol・ L-1 concentration of gemcitabine for 0,3,7,10,13 and 16 days, the apoptosis ratio was determinated by flow cytometry .And the mRNA and protein levels of APE/Ref -1 of survival cells were deter-mined by reverse transcription -polymerase chain reaction ( RT-PCR) and Western blot , respectively.Results After human breast cancer cell line MCF-7 was incubated with 50 nmol・ L -1 gemcitabine for 0,3,7, 10,13 and 16 days,the expression of APE/Ref-1 in human breast can-cer cell line MCF-7 was elevated significantly both at mRNA and pro-tein levels ,and were positively correlated with incubation time , which is consistent with the proportion of apototic cells .And the expression of APE/Ref-1 was increasing significantly from tenthdays , reaching the highest in sixteenth days .And when the drug resistant cells was com-pared with the non -drug resistant cells , which were both incubated with 50 nmol・ L-1 gemcitabine for 10,13 and 16 days.The expression of mRNA and protein of APE/Ref-1 in drug resistant cells have statistical significance ( P<0.05 ).Conclusion The obvious up -regulated expression of APE/Ref-1 may be an adaptive re-sponse contributing to the overall chemoresistance in breast cancer .%目的:研究人乳腺癌 MCF -7细胞株经吉西他滨处理后 APE/Ref -1 mRNA和蛋白表达的变化。方法以50 nmol・ L-1吉西他滨处理乳腺癌MCF-7细胞,在处理后0,3,7,10,13和16天,测定细胞凋亡比例、存活细胞APE/Ref-1基因mRNA及蛋白表达情况。结果吉西他滨50 nmol・ L-1干预后第0,3,7,10,13,16天,细胞APE/Ref-1 mRNA及蛋白表达水平均逐渐增加,

  2. The enzyme-amplified amperometric DNA sensor using an electrodeposited polymer redox mediator

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A highly sensitive method for the detection of a breast cancer-associated BRCA-1 gene is reported. The detection is based on a classical sandwich-type assay using horseradish peroxidase (HRP) as a catalytic label and electrodeposited Os2+/3+ conducting polymer (PAA-PVI-Os) as a redox mediator. Target DNA could be detected by the HRP-catalyzed reduction of H2O2, leading to a limit of detection as low as 10 fM.

  3. Redox chemistry of green tea polyphenols: therapeutic benefits in neurodegenerative diseases.

    Science.gov (United States)

    Hügel, H M; Jackson, N

    2012-05-01

    Evidence for the medicinal and health benefits of polyphenols in green tea for the prevention of chronic diseases such as heart disease, various types of cancer and neurodegenerative diseases is advancing. Their in vivo effectiveness and molecular mechanisms are difficult to elucidate and remain a challenging task. We review the redox responsiveness and amyloid protein perturbation biophysical properties of the major green tea polyphenol constituent (-)- epigallocatechin-3-gallate [EGCG].

  4. Potentiometric Measurements of Semiconductor Nanocrystal Redox Potentials.

    Science.gov (United States)

    Carroll, Gerard M; Brozek, Carl K; Hartstein, Kimberly H; Tsui, Emily Y; Gamelin, Daniel R

    2016-04-06

    A potentiometric method for measuring redox potentials of colloidal semiconductor nanocrystals (NCs) is described. Fermi levels of colloidal ZnO NCs are measured in situ during photodoping, allowing correlation of NC redox potentials and reduction levels. Excellent agreement is found between electrochemical and optical redox-indicator methods. Potentiometry is also reported for colloidal CdSe NCs, which show more negative conduction-band-edge potentials than in ZnO. This difference is highlighted by spontaneous electron transfer from reduced CdSe NCs to ZnO NCs in solution, with potentiometry providing a measure of the inter-NC electron-transfer driving force. Future applications of NC potentiometry are briefly discussed.

  5. The Ape-1/Ref-1 redox antagonist E3330 inhibits the growth of tumor endothelium and endothelial progenitor cells: therapeutic implications in tumor angiogenesis.

    Science.gov (United States)

    Zou, Gang-Ming; Karikari, Collins; Kabe, Yasuaki; Handa, Hiroshi; Anders, Robert A; Maitra, Anirban

    2009-04-01

    The apurinic/apyrimidinic endonuclease 1/redox factor-1 (Ape-1/Ref-1) is a multi-functional protein, involved in DNA repair and the activation of redox-sensitive transcription factors. The Ape-1/Ref-1 redox domain acts as a cytoprotective element in normal endothelial cells, mitigating the deleterious effects of apoptotic stimuli through induction of survival signals. We explored the role of the Ape-1/Ref-1 redox domain in the maintenance of tumor-associated endothelium, and of endothelial progenitor cells (EPCs), which contribute to tumor angiogenesis. We demonstrate that E3330, a small molecule inhibitor of the Ape-1/Ref-1 redox domain, blocks the in vitro growth of pancreatic cancer-associated endothelial cells (PCECs) and EPCs, which is recapitulated by stable expression of a dominant-negative redox domain mutant. Further, E3330 blocks the differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) into CD31(+) endothelial progeny. Exposure of PCECs to E3330 results in a reduction of H-ras expression and intracellular nitric oxide (NO) levels, as well as decreased DNA-binding activity of the hypoxia-inducible transcription factor, HIF-1alpha. E3330 also reduces secreted and intracellular vascular endothelial growth factor expression by pancreatic cancer cells, while concomitantly downregulating the cognate receptor Flk-1/KDR on PCECs. Inhibition of the Ape-1/Ref-1 redox domain with E3330 or comparable angiogenesis inhibitors might be a potent therapeutic strategy in solid tumors.

  6. Repositioning and steering laser beam power via coherent combination of multiple Airy beams.

    Science.gov (United States)

    Zhang, Ze; Ye, Zhuoyi; Song, Daohong; Zhang, Peng; Chen, Zhigang

    2013-12-10

    We study numerically and experimentally laser coherent combination (LCC) with multiple one- or two-dimensional Airy beams. It is shown that the method of LCC using Airy beams leads to a higher combining efficiency and a better feature of propagation than that using conventional Gaussian beams. Based on such coherent Airy beams combination, we propose a laser steering approach that could achieve large-angle beam steering (over 0.6°) without the need of using any mechanical steering component.

  7. Thiol Redox Sensitivity of Two Key Enzymes of Heme Biosynthesis and Pentose Phosphate Pathways: Uroporphyrinogen Decarboxylase and Transketolase

    Directory of Open Access Journals (Sweden)

    Brian McDonagh

    2013-01-01

    Full Text Available Uroporphyrinogen decarboxylase (Hem12p and transketolase (Tkl1p are key mediators of two critical processes within the cell, heme biosynthesis, and the nonoxidative part of the pentose phosphate pathway (PPP. The redox properties of both Hem12p and Tkl1p from Saccharomyces cerevisiae were investigated using proteomic techniques (SRM and label-free quantification and biochemical assays in cell extracts and in vitro with recombinant proteins. The in vivo analysis revealed an increase in oxidized Cys-peptides in the absence of Grx2p, and also after treatment with H2O2 in the case of Tkl1p, without corresponding changes in total protein, demonstrating a true redox response. Out of three detectable Cys residues in Hem12p, only the conserved residue Cys52 could be modified by glutathione and efficiently deglutathionylated by Grx2p, suggesting a possible redox control mechanism for heme biosynthesis. On the other hand, Tkl1p activity was sensitive to thiol redox modification and although Cys622 could be glutathionylated to a limited extent, it was not a natural substrate of Grx2p. The human orthologues of both enzymes have been involved in certain cancers and possess Cys residues equivalent to those identified as redox sensitive in yeast. The possible implication for redox regulation in the context of tumour progression is put forward.

  8. Modeling, Validation, and Control of Electronically Actuated Pitman Arm Steering for Armored Vehicle

    Directory of Open Access Journals (Sweden)

    Vimal Rau Aparow

    2016-01-01

    Full Text Available In this study, 2 DOF mathematical models of Pitman arm steering system are derived using Newton’s law of motion and modeled in MATLAB/SIMULINK software. The developed steering model is included with a DC motor model which is directly attached to the steering column. The Pitman arm steering model is then validated with actual Pitman arm steering test rig using various lateral inputs such as double lane change, step steer, and slalom test. Meanwhile, a position tracking control method has been used in order to evaluate the effectiveness of the validated model to be implemented in active safety system of a heavy vehicle. The similar method has been used to test the actual Pitman arm steering mechanism using hardware-in-the-loop simulation (HILS technique. Additional friction compensation is added in the HILS technique in order to minimize the frictional effects that occur in the mechanical configuration of the DC motor and Pitman arm steering. The performance of the electronically actuated Pitman arm steering system can be used to develop a firing-on-the-move actuator (FOMA for an armored vehicle. The FOMA can be used as an active safety system to reject unwanted yaw motion due to the firing force.

  9. Theoretical modeling on the laser induced effect of liquid crystal optical phased beam steering

    Science.gov (United States)

    He, Xiaoxian; Wang, Xiangru; Wu, Liang; Tan, Qinggui; Li, Man; Shang, Jiyang; Wu, Shuanghong; Huang, Ziqiang

    2017-01-01

    Non-mechanical laser beam steering has been reported previously in liquid crystal array devices. To be one of the most promising candidates to be practical non-mechanical laser deflector, its laser induced effect still has few theoretical model. In this paper, we propose a theoretical model to analyze this laser induced effect of LC-OPA to evaluate the deterioration on phased beam steering. The model has three parts: laser induced thermal distribution; temperature dependence of material parameters and beam steering deterioration. After these three steps, the far field of laser beam is obtained to demonstrate the steering performance with the respect to the incident laser beam power and beam waist.

  10. Cycling around a curve: the effect of cycling speed on steering and gaze behavior.

    Directory of Open Access Journals (Sweden)

    Pieter Vansteenkiste

    Full Text Available Although it is generally accepted that visual information guides steering, it is still unclear whether a curvature matching strategy or a 'look where you are going' strategy is used while steering through a curved road. The current experiment investigated to what extent the existing models for curve driving also apply to cycling around a curve, and tested the influence of cycling speed on steering and gaze behavior. Twenty-five participants were asked to cycle through a semicircular lane three consecutive times at three different speeds while staying in the center of the lane. The observed steering behavior suggests that an anticipatory steering strategy was used at curve entrance and a compensatory strategy was used to steer through the actual bend of the curve. A shift of gaze from the center to the inside edge of the lane indicates that at low cycling speed, the 'look where you are going' strategy was preferred, while at higher cycling speeds participants seemed to prefer the curvature matching strategy. Authors suggest that visual information from both steering strategies contributes to the steering system and can be used in a flexible way. Based on a familiarization effect, it can be assumed that steering is not only guided by vision but that a short-term learning component should also be taken into account.

  11. Cycling around a curve: the effect of cycling speed on steering and gaze behavior.

    Science.gov (United States)

    Vansteenkiste, Pieter; Van Hamme, David; Veelaert, Peter; Philippaerts, Renaat; Cardon, Greet; Lenoir, Matthieu

    2014-01-01

    Although it is generally accepted that visual information guides steering, it is still unclear whether a curvature matching strategy or a 'look where you are going' strategy is used while steering through a curved road. The current experiment investigated to what extent the existing models for curve driving also apply to cycling around a curve, and tested the influence of cycling speed on steering and gaze behavior. Twenty-five participants were asked to cycle through a semicircular lane three consecutive times at three different speeds while staying in the center of the lane. The observed steering behavior suggests that an anticipatory steering strategy was used at curve entrance and a compensatory strategy was used to steer through the actual bend of the curve. A shift of gaze from the center to the inside edge of the lane indicates that at low cycling speed, the 'look where you are going' strategy was preferred, while at higher cycling speeds participants seemed to prefer the curvature matching strategy. Authors suggest that visual information from both steering strategies contributes to the steering system and can be used in a flexible way. Based on a familiarization effect, it can be assumed that steering is not only guided by vision but that a short-term learning component should also be taken into account.

  12. Cancer

    Science.gov (United States)

    ... uses a surgical tool to remove the tumor.Mohs' surgery. Layers of cancer cells are removed one ... usually have not been approved by the U.S. Food and Drug Administration (FDA). The medicine may have ...

  13. Electrical Connection of Enzyme Redox Centers to Electrodes

    Science.gov (United States)

    1992-03-20

    complex with a water soluble diepoxide to form a hydrophilic, substrate and product permeable -lItm thick redox epoxy film. In redox-epoxy film based...product permeable -ltm thick redox epoxy film. In redox-epoxy film based glucose sensors interference by electrooxidizable ascorbate, urate and...inhalation (derived of the large lung surface area) and continuous, non-invasive administration, in the case of iontophoresis . The use of these

  14. Architectural evaluation of beam-steered shuffle optical interconnect

    Science.gov (United States)

    Murdocca, Miles J.; Batchu, Ravi V.; Dennison, Michael

    1996-06-01

    We report on a reconfigurable optical interconnection approach in which static communication graphs are extracted from high level programs and are mapped onto a two stage optical beam-steered/perfect shuffle interconnect. An array of processing elements (PEs) is partitioned into functional units of equal size that are served by one optical input/output (I/O) port per PE. PEs within a functional unit can use any of the optical I/O ports served by that functional unit. An optical beam-steering mechanism in conjunction with an optical perfect shuffle interconnects the functional units. At the highest level, computer programs are written in the Id dataflow programming language. At the next level, dataflow graphs (communication graphs that represent the natural parallelism in a computation) are automatically extracted from the high-level programs. At the lowest level, the dataflow graphs are mapped onto the optical beam-steered/perfect shuffle interconnect. This mapping step is facilitated by a mechanism that redirects optical beams to that the physical interconnect takes the form of the dataflow graph. An intended application is to create low latency realizations of specialized hardware on-the-fly, such as for rapid prototyping. An advantage of this approach over competing all-electronic or static free-space optical interconnection approaches is that the optical interconnect has low depth (two stages) with low fan-out (typically 1 to 3). In previous work, the behaviors of the mappings are studied for randomly generated dataflow graphs. In the work reported here, the behaviors of the mappings are studied for extracted dataflow graphs. We conclude that this interconnection approach is effective for extracted dataflow graphs, using only a single pass through the network, if the interconnect is augmented with a small crossbar within each functional unit.

  15. Le reazioni redox: un pasticcio concettuale?

    Directory of Open Access Journals (Sweden)

    Elena Ghibaudi

    2015-10-01

    Full Text Available Le reazioni di ossidoriduzione costituiscono un argomento centrale di qualsiasi corso di base di chimica, sia a livello scolastico che universitario. Il loro apprendimento comporta il superamento di svariati ostacoli concettuali, la cui difficoltà può risultare amplificata da prassi didattiche inadeguate. Gli errori più ricorrenti nel presentare l’argomento sono di due tipi: i fare implicitamente riferimento a modelli esplicativi distinti (es. il numero di ossidazione e il trasferimento elettronico, senza esplicitarli e senza evidenziarne la differente natura e il campo di validità; ii confondere il livello della spiegazione formale con quello della realtà fisica. I fenomeni redox sono normalmente interpretati sulla base di tre distinti modelli empirici, che fanno riferimento al trasferimento di atomi di ossigeno, di atomi di idrogeno, di elettroni; e di un quarto modello, formale, fondato sul cambiamento del numero di ossidazione. La confusione tra questi modelli può generare considerevoli problemi di apprendimento. Il presente lavoro riporta un’analisi critica delle implicazioni concettuali della didattica dei processi redox. L’analisi è articolata in tre sezioni: i disamina della evoluzione storica del concetto di ossidoriduzione; ii analisi dei modelli redox e del loro campo di validità; iii discussione di alcuni aspetti epistemologici inerenti i processi redox che sono rilevanti per la didattica della chimica.

  16. Methods for using redox liposome biosensors

    Science.gov (United States)

    Cheng, Quan; Stevens, Raymond C.

    2002-01-01

    The present invention provides methods and compositions for detecting the presence of biologically-important analytes by using redox liposome biosensors. In particular, the present invention provides liposome/sol-gel electrodes suitable for the detection of a wide variety of organic molecules, including but not limited to bacterial toxins.

  17. Metathetical Redox Reaction of (Diacetoxyiodoarenes and Iodoarenes

    Directory of Open Access Journals (Sweden)

    Antoine Jobin-Des Lauriers

    2015-12-01

    Full Text Available The oxidation of iodoarenes is central to the field of hypervalent iodine chemistry. It was found that the metathetical redox reaction between (diacetoxyiodoarenes and iodoarenes is possible in the presence of a catalytic amount of Lewis acid. This discovery opens a new strategy to access (diacetoxyiodoarenes. A computational study is provided to rationalize the results observed.

  18. Redox regulation of transient receptor potential channels.

    OpenAIRE

    2014-01-01

    Abstract Significance: Environmental and endogenous reactive species such as reactive oxygen species (ROS), reactive nitrogen species (RNS), and other electrophiles are not only known to exert toxic effects on organisms, but are also emerging as molecules that mediate cell signaling responses. However, the mechanisms underlying this cellular redox signaling by reactive species remains largely uncharacterized.

  19. Redox Transformations of Mercury in Wetlands

    Science.gov (United States)

    Amyot, M.

    2007-12-01

    Wetlands are valued for their high biodiversity and for their ecosystem services. However, we still have a poor understanding of their role in the redox transformation of contaminants such as mercury. We first propose a brief overview of past studies conducted on wetlands from different latitudes. In most instances, photochemical processes are determinant in the upper portion of the water column. At the sediment/water interface, evidence is currently supporting a significant contribution of bacterial communities, as promoters of Hg(II) reduction, particularly in the presence of anoxia. A multi-year study was recently conducted on Hg redox cycling in a fluvial wetland of the St. Lawrence River, where wetland restoration could have unintended consequences. In addition to photochemistry and bacterial reduction, Hg redox cycling was affected by epiphytes living on macrophytes, through adsorption/absorption processes. Redox studies such as this one have been historically seen as having implication for water/air flux studies, since Hg(0) is volatile. We here also discuss the potential bioavailability of Hg(0) towards bacteria. An emerging axis of our wetland research effort deals with beaver dams, which are in expansion and shown to produce high levels of methylHg

  20. Bimetallic redox synergy in oxidative palladium catalysis.

    Science.gov (United States)

    Powers, David C; Ritter, Tobias

    2012-06-19

    Polynuclear transition metal complexes, which are embedded in the active sites of many metalloenzymes, are responsible for effecting a diverse array of oxidation reactions in nature. The range of chemical transformations remains unparalleled in the laboratory. With few noteworthy exceptions, chemists have primarily focused on mononuclear transition metal complexes in developing homogeneous catalysis. Our group is interested in the development of carbon-heteroatom bond-forming reactions, with a particular focus on identifying reactions that can be applied to the synthesis of complex molecules. In this context, we have hypothesized that bimetallic redox chemistry, in which two metals participate synergistically, may lower the activation barriers to redox transformations relevant to catalysis. In this Account, we discuss redox chemistry of binuclear Pd complexes and examine the role of binuclear intermediates in Pd-catalyzed oxidation reactions. Stoichiometric organometallic studies of the oxidation of binuclear Pd(II) complexes to binuclear Pd(III) complexes and subsequent C-X reductive elimination from the resulting binuclear Pd(III) complexes have confirmed the viability of C-X bond-forming reactions mediated by binuclear Pd(III) complexes. Metal-metal bond formation, which proceeds concurrently with oxidation of binuclear Pd(II) complexes, can lower the activation barrier for oxidation. We also discuss experimental and theoretical work that suggests that C-X reductive elimination is also facilitated by redox cooperation of both metals during reductive elimination. The effect of ligand modification on the structure and reactivity of binuclear Pd(III) complexes will be presented in light of the impact that ligand structure can exert on the structure and reactivity of binuclear Pd(III) complexes. Historically, oxidation reactions similar to those discussed here have been proposed to proceed via mononuclear Pd(IV) intermediates, and the hypothesis of mononuclear Pd

  1. Hierarchical Visual Analysis and Steering Framework for Astrophysical Simulations

    Institute of Scientific and Technical Information of China (English)

    肖健; 张加万; 原野; 周鑫; 纪丽; 孙济洲

    2015-01-01

    A framework for accelerating modern long-running astrophysical simulations is presented, which is based on a hierarchical architecture where computational steering in the high-resolution run is performed under the guide of knowledge obtained in the gradually refined ensemble analyses. Several visualization schemes for facilitating ensem-ble management, error analysis, parameter grouping and tuning are also integrated owing to the pluggable modular design. The proposed approach is prototyped based on the Flash code, and it can be extended by introducing user-defined visualization for specific requirements. Two real-world simulations, i.e., stellar wind and supernova remnant, are carried out to verify the proposed approach.

  2. AN ALGORITHM FOR STEERING CONTROL WITH SIMULATION RESULTS

    OpenAIRE

    Apeksha V. Sakhare,; Prof. Dr. V. M. Thakare; Prof. R. V. Dharaskar

    2010-01-01

    The idea behind the paper was channelization of human thoughts to automated realization. It is decided to implement the theme of automatic maneuvering of vehicles and the unanimous choice of sensor was touch screen. It was started with the thought of being able to replace the steering of a car completely by a touch screen. It is drawn on the experience of driving to reach at the choice of touch screen as a drive interface. Another innovation was the touch screen controller being wireless. The...

  3. Frequency-dependent optical steering from subwavelength plasmonic structures.

    Science.gov (United States)

    Djalalian-Assl, A; Gómez, D E; Roberts, A; Davis, T J

    2012-10-15

    We show theoretically and with numerical simulations that the direction of the in-plane scattering from a subwavelength optical antenna system can be controlled by the frequency of the incident light. This optical steering effect does not rely on propagation phase shifts or diffraction but arises from phase shifts in the localized surface plasmon modes of the antenna. An analytical model is developed to optimize the parameters for the configuration, showing good agreement with a rigorous numerical simulation. The simulation predicts a 25° angular shift in the direction of the light scattered from two gold nanorods for a wavelength change of 12 nm.

  4. Adaptive feedback linearization applied to steering of ships

    Directory of Open Access Journals (Sweden)

    Thor I. Fossen

    1993-10-01

    Full Text Available This paper describes the application of feedback linearization to automatic steering of ships. The flexibility of the design procedure allows the autopilot to be optimized for both course-keeping and course-changing manoeuvres. Direct adaptive versions of both the course-keeping and turning controller are derived. The advantages of the adaptive controllers are improved performance and reduced fuel consumption. The application of nonlinear control theory also allows the designer in a systematic manner to compensate for nonlinearities in the control design.

  5. Correlation steering in the angularly multimode Raman atomic memory.

    Science.gov (United States)

    Mazelanik, Mateusz; Dąbrowski, Michał; Wasilewski, Wojciech

    2016-09-19

    We present the possibility of steering the direction of correlations between the off-resonant Raman scattered photons from the angularly multimode atomic memory based on warm rubidium vapors. Using acousto-optic deflectors (AOD) driven by different modulation frequencies, we experimentally change the angle of incidence of the laser beams on the atomic ensemble. By performing correlation measurements for various deflection angles, we verify that we can choose the anti-Stokes light propagation direction independently of the correlated Stokes scattered light in a continuous way. As a result we can select the spatial mode of photons retrieved from the memory, which may be important for future development of quantum information processing.

  6. Superdirective dielectric nanoantennas with effect of light steering

    CERN Document Server

    Krasnok, Alexander; Slobozhanyuk, Alexey; Simovski, Constantin; Belov, Pavel; Kivshar, Yuri

    2013-01-01

    We introduce a novel concept of superdirective antennas based on the generation of higher-order optically-induced magnetic multipole modes. All-dielectric nanoantenna can be realized as an optically small spherical dielectric nanoparticle with a notch excited by a point source (e.g. a quantum dot) located in the notch. The superdirectivity effect is not associated with high dissipative losses. For these dielectric nanoantennas we predict the effect of the beam steering at the nanoscale characterized by a subwavelength sensitivity of the beam radiation direction to the source position. We confirm the predicted effects experimentally through the scaling to the microwave frequency range.

  7. Evaluation of Potential Usage of Incremental-Type Rotary Encoder Application for Angle Sensing in Steering System

    Directory of Open Access Journals (Sweden)

    Sunarto Kaleg

    2014-12-01

    Full Text Available The main target of a steering system is that the driver can change vehicle trajectory in accordance with the desired direction.  Power steering has become a standard feature in automobile.  It provides assisting power when the driver turns the steering wheel. The well-known power steering types include; Hydraulic Power Steering (HPS, Electro - Hydraulic Power Steering (EHPS, and Electric Power Steering (EPS. EHPS or EPS uses an Electronic Control Unit (ECU which is specific for each vehicle. The ECU should be able to regulate power of electric motor to provide corresponding assisting power for the steering wheel. Therefore ECU requires input signals, one of which is vehicle wheel angle that can be indicated from the vehicle steering wheel angle. Incremental type of Rotary Encoder (RE is used in steering angle sensor on a minibus. RE specification used was 60 pulses per rotation and the minibus steering transmission specification is 3.5 round of right wheel off angle to the left wheel off angle. So we get the RE angular resolution 6ºper pulse and 105 number of pulses to half of the steering transmission ratio. Repeatability then tested against to a steering angle counter module. Testing is done with a test cycle consisting of 3 repetitions: condition center of the steering wheel, the steering wheel is turned to full right, then to the full left, then back to the right up to the steering wheel center. The results obtained 2 pulses deviation, or equivalent to 12º of steering angle.

  8. Growth, carcass characteristics, and profitability of organic versus conventional dairy beef steers.

    Science.gov (United States)

    Bjorklund, E A; Heins, B J; Dicostanzo, A; Chester-Jones, H

    2014-03-01

    Bull calves (n=49), born at the University of Minnesota West Central Research and Outreach Center (Morris) between March and May 2011, were used to compare growth measurements and profitability of conventional and organic dairy steers. Calves were assigned to 1 of 3 replicated groups at birth: conventional (CONV; n=16), organic (pasture and concentrate; ORG; n=16), or organic grass only (GRS; n=17), and analysis of variables was on a pen basis. Breed groups of calves were Holstein (HO; n=9); Holsteins (n=11) maintained at 1964 breed average level; crossbreds (n=19) including combinations of HO, Montbéliarde, and Swedish Red; and crossbreds (n=10) including combinations of HO, Jersey, Swedish Red, and Normande. The CONV steers were fed a diet of 80% concentrate and 20% forage. The ORG steers were fed a diet of organic corn, organic corn silage, and at least 30% of their diet consisted of organic pasture during the grazing season. The GRS steers grazed pasture during the grazing season and were fed high-quality hay or hay silage during the nongrazing season. Intakes of a total mixed ration were recorded daily with herd management software. A profit function was defined to include revenues and expenses for beef value, feed intake, pasture intake, health cost, and yardage. The GRS (358.6 kg) steers had lesser total gains from birth to slaughter than ORG (429.6 kg) and CONV (534.5 kg) steers. Furthermore, the GRS (0.61 kg/d) steers had lesser average daily gain from birth compared with ORG (0.81 kg/d) and CONV (1.1 kg/d) steers. The GRS and ORG steers had smaller rib eye area (49.5 and 65.8 cm(2), respectively) compared with CONV (75.4 cm(2)) steers. For profitability, GRS steers had 43% greater profit than CONV steers due to organic beef price premiums and lower feed costs. On the other hand, ORG steers had substantially less profit than CONV steers. The higher cost of production for the ORG steers is due to the extreme high value of organic corn. The results of the

  9. Protein redox chemistry: post-translational cysteine modifications that regulate signal transduction and drug pharmacology

    Directory of Open Access Journals (Sweden)

    Revati eWani

    2014-10-01

    Full Text Available The perception of reactive oxygen species (ROS has evolved over the past decade from agents of cellular damage to secondary messengers which modify signaling proteins in physiology and the disease state (e.g. cancer. New protein targets of specific oxidation are rapidly being identified. One emerging class of redox modification occurs to the thiol side chain of cysteine residues which can produce multiple chemically-distinct alterations to the protein (e.g. sulfenic/sulfinic/sulfonic acid, disulfides. These post-translational modifications (PTM are shown to affect the protein structure and function. Because redox-sensitive proteins can traffic between subcellular compartments that have different redox environments, cysteine oxidation enables a spatio-temporal control to signaling. Understanding ramifications of these oxidative modifications to the functions of signaling proteins is crucial for understanding cellular regulation as well as for informed-drug discovery process. The effects of EGFR oxidation of Cys797 on inhibitor pharmacology are presented to illustrate the principle. Taken together, cysteine redox PTM can impact both cell biology and drug pharmacology.

  10. Redox proteomics for the assessment of redox-related posttranslational regulation in plants.

    Science.gov (United States)

    Mock, Hans-Peter; Dietz, Karl-Josef

    2016-08-01

    The methodological developments of in vivo and in vitro protein labeling and subsequent detection enable sensitive and specific detection of redox modifications. Such methods are presently applied to diverse cells and tissues, subproteomes and developmental as well as environmental conditions. The chloroplast proteome is particularly suitable for such kind of studies, because redox regulation of chloroplast proteins is well established, many plastid proteins are abundant, redox network components have been inventoried in great depth, and functional consequences explored. Thus the repertoire of redox-related posttranslational modifications on the one hand side and their abundance on the other pose a challenge for the near future to understand their contribution to physiological regulation. The various posttranslational redox modifications are introduced, followed by a description of the available proteomics methods. The significance of the redox-related posttranslational modification is exemplarily worked out using established examples from photosynthesis. This article is part of a Special Issue entitled: Plant Proteomics--a bridge between fundamental processes and crop production, edited by Dr. Hans-Peter Mock.

  11. Carcass characteristics and composition of Brahman, angus and Brahman x Angus steers fed for different times-on-feed.

    Science.gov (United States)

    Lunt, D K; Smith, G C; Murphey, C E; Savell, J W; Carpenter, Z L; Petersen, H D

    1985-01-01

    Twenty-five steers of each of three breedtypes (Angus, Brahman and F(1) Brahman x Angus) were sorted by frame size and muscle thickness, assigned to groups (five steers of each breedtype) to be fed for 0, 56, 112, 168 or 224 days, slaughtered and compared for various carcass traits. Steers of each breedtype had similar dressing percentages. Carcasses from all three breedtypes merited similar USDA quality and yield grades; breedtypes differences in quality grade were slight. Differences were found in the fat deposition patterns exhibited by the three breedtypes. Brahman steers tended to deposit more of their total fat as subcutaneous fat early in the feeding period. Angus steers had more (P carcass weight at all five feeding periods and more (P Brahman steers. Brahman steers had a higher percentage of their separable lean in the muscles of the round than did steers of the other breedtypes.

  12. Integrating deflection models and image feedback for real-time flexible needle steering

    NARCIS (Netherlands)

    Abayazid, Momen; Roesthuis, Roy J.; Reilink, Rob; Misra, Sarthak

    2012-01-01

    Needle insertion procedures are commonly used for diagnostic and therapeutic purposes. In this paper, an image- guided control system is developed to robotically steer flexible nee- dles with an asymmetric tip. Knowledge about needle deflection is required for accurate steering. Two different models

  13. Reducing Digging Losses by Using Automated Steering to Plant and Invert Peanuts

    Directory of Open Access Journals (Sweden)

    George Vellidis

    2014-07-01

    Full Text Available GPS guidance of farm machinery has been increasingly adopted by farmers because of the perceived gains in efficiency that it provides. In the southeastern USA one of the reasons farmers adopt GPS guidance, and specifically automated steering (auto-steer, is that it can theoretically result in large yield gains when used to plant and invert peanuts—one of the region’s most important crops. The goal of our study was to quantify the yield benefit of using real time kinematic (RTK-based auto-steer to plant and invert peanuts under a variety of terrain conditions. Yield benefits result from reduced digging losses. The study was conducted for two consecutive years (2010 and 2011 on a private farm in Georgia, USA. When all data are grouped together, auto-steer outperformed conventional by 579 kg/ha in 2010 and 451 kg/ha in 2011. We also evaluated the performance of auto-steer under different curvature conditions using low, medium, and high curvature rows. The results showed that auto-steer outperformed conventional under all curvature by a minimum of 338 kg/ha. Finally, we evaluated passive implement guidance in combination with auto-steer and found that it holds tremendous potential for further reducing digging losses. In many cases, auto-steer will pay for itself within a year.

  14. Does pedalling on a recumbent bicycle influence the cyclist’s steering behaviour?

    NARCIS (Netherlands)

    Boon, K.M.; Klap, P.; Van Lanen, J.A.; Letsoin, G.J.; Jansen, A.J.

    2014-01-01

    The paper presents the answer to the question how pedalling on a specific recumbent bicycle, such as the VeloX3, influences a cyclist’s ability to steer the bicycle. The research aims to find the correlation between pedalling and the undesired steering movements it creates. To test this assumption a

  15. Dynamic Modeling of Hydraulic Power Steering System with Variable Ratio Rack and Pinion Gear

    Science.gov (United States)

    Zhang, Nong; Wang, Miao

    A comprehensive mathematical model of a typical hydraulic power steering system equipped with variable ratio rack and pinion gear is developed. The steering system’s dynamic characteristics are investigated and its forced vibrations are compared with those obtained from a counterpart system with a constant ratio rack and pinion gear. The modeling details of the mechanism subsystem, hydraulic supply lines subsystem and the rotary spool valve subsystem are provided and included in the integrated steering system model. The numerical simulations are conducted to investigate the dynamics of the nonlinear parametric steering system. From the comparison between simulated results and the experimental ones, it is shown that the model accurately integrates the boost characteristics of the rotary spool valve which is the key component of hydraulic power steering system. The variable ratio rack-pinion gear behaviors significantly differently from its constant ratio counterpart does. It significantly affects not only the system natural frequencies but also reduces vibrations under constant rate and ramp torque steering inputs. The developed steering model produces valid predictions of the system’s behavior and therfore could assist engineers in the design and analysis of integrated steering systems.

  16. Effects of steering demand on lane keeping behaviour, self-reports, and physiology : A simulator study

    NARCIS (Netherlands)

    Dijksterhuis, Chris; Brookhuis, Karel A.; De Waard, Dick

    2011-01-01

    In this study a driving simulator was used to determine changes in mental effort in response to manipulations of steering demand. Changes in mental effort were assessed by using subjective effort ratings, physiology, and the standard deviation of the lateral position. Steering demand was increased b

  17. Relationship of leptin concentrations with feed intake, growth, and efficiency in finishing beef steers

    Science.gov (United States)

    The objective of this experiment was to determine the association of serum leptin concentrations with production measures including DMI, ADG, G:F as well as carcass characteristics in genetically diverse finishing beef steers. Three cohorts of steers (n = 473 total) were individually fed a finishin...

  18. 46 CFR 130.130 - Steering on OSVs of less than 100 gross tons.

    Science.gov (United States)

    2010-10-01

    ... must be installed in the pilothouse to indicate operation of the power units. (e) The auxiliary means... 46 Shipping 4 2010-10-01 2010-10-01 false Steering on OSVs of less than 100 gross tons. 130.130... VESSEL CONTROL, AND MISCELLANEOUS EQUIPMENT AND SYSTEMS Vessel Control § 130.130 Steering on OSVs of...

  19. Differential acute phase immune responses by Angus and Romosinuano steers following an endotoxin challenge

    Science.gov (United States)

    Our primary objective was to evaluate potential genetic differences between two diverse Bos taurus breeds (Angus (AG) and Romosinuano (RO)) in response to an endotoxin. The RO is a tropically adaptive Bos taurus breed developed in the Sinú valley of northern Colombia. Eighteen steers (n = 9 steers/b...

  20. Exogenous administration of lipids to steers alters aspects of the innate immune response to endotoxin challenge

    Science.gov (United States)

    Limitations in energy availability are known to impede the efficiency of the immune response to endotoxemia. Therefore, this study examined the effects of increasing energy availability on the pro-inflammatory response to LPS in Holstein steers. Steers were randomly assigned to 1 of 3 groups (n = 7 ...

  1. Two dimensional thermo-optic beam steering using a silicon photonic optical phased array

    Science.gov (United States)

    Mahon, Rita; Preussner, Marcel W.; Rabinovich, William S.; Goetz, Peter G.; Kozak, Dmitry A.; Ferraro, Mike S.; Murphy, James L.

    2016-03-01

    Components for free space optical communication terminals such as lasers, amplifiers, and receivers have all seen substantial reduction in both size and power consumption over the past several decades. However, pointing systems, such as fast steering mirrors and gimbals, have remained large, slow and power-hungry. Optical phased arrays provide a possible solution for non-mechanical beam steering devices that can be compact and lower in power. Silicon photonics is a promising technology for phased arrays because it has the potential to scale to many elements and may be compatible with CMOS technology thereby enabling batch fabrication. For most free space optical communication applications, two-dimensional beam steering is needed. To date, silicon photonic phased arrays have achieved two-dimensional steering by combining thermo-optic steering, in-plane, with wavelength tuning by means of an output grating to give angular tuning, out-of-plane. While this architecture might work for certain static communication links, it would be difficult to implement for moving platforms. Other approaches have required N2 controls for an NxN element phased array, which leads to complexity. Hence, in this work we demonstrate steering using the thermo-optic effect for both dimensions with a simplified steering mechanism requiring only two control signals, one for each steering dimension.

  2. Modulation of the acute phase response in feedlot steers supplemented with Saccharomyces cerevisiae

    Science.gov (United States)

    This study was designed to determine the effect of supplementing feedlot steers with Saccharomyces cerevisiae CNCM I-1079 (SC) on the acute phase response to a lipopolysaccharide (LPS) challenge. Steers (n = 18; 266 ± 4 kilograms body weight) were separated into three treatment groups (n = 6/treatm...

  3. Design and Development of Labview Based Steering Wheel Angle Sensor System

    Directory of Open Access Journals (Sweden)

    Tony George

    2015-04-01

    Full Text Available Conventional angle sensors can measure only 360°,but passenger car steering wheel turns through +/-720o (a total of 4 complete turns. In this paper we describe iGMR based steering wheel angle sensor implementation which can be used as a rotation sensor to measure +/- 720°.

  4. Application of washed rumen technique for rapid determination of fasting heat production in steers

    Science.gov (United States)

    Two experiments were conducted to evaluate the use of a washed rumen technique as an alternative approach for determining fasting HP in cattle. In Exp. 1, 8 Holstein steers (322±30 kg) were adapted to a cubed alfalfa-based diet (1.5xNEm) for 10 d. After which steers were placed into individual hea...

  5. Optimized detection of steering via linear criteria for arbitrary-dimensional states

    Science.gov (United States)

    Zheng, Yu-Lin; Zhen, Yi-Zheng; Cao, Wen-Fei; Li, Li; Chen, Zeng-Bing; Liu, Nai-Le; Chen, Kai

    2017-03-01

    Einstein-Podolsky-Rosen (EPR) steering, as a new form of nonlocality, stands between entanglement and Bell nonlocality, implying promising applications for quantum information tasks. The problem of detecting EPR steering plays an important role in characterization of quantum nonlocality. Despite some significant progress, one still faces a practical issue: how to detect EPR steering in an experimentally friendly fashion. Resorting to an EPR steering inequality, one is required to apply a strategy as efficiently as possible for any selected measurement settings on the two subsystems, one of which may not be trusted. Inspired by the recent powerful linear criteria proposed by Saunders et al. [D. J. Saunders, S. J. Jones, H. M. Wiseman, and G. J. Pryde, Nat. Phys. 6, 845 (2010)., 10.1038/nphys1766], we present an optimized method of certifying steering for an arbitrary-dimensional state in a cost-effective manner. We provide a practical way to signify steering via only a few settings to optimally violate the steering inequality. Our method leads to steering detections in a highly efficient way, and can be performed with any number of settings, for an arbitrary bipartite mixed state, which can reduce experimental overheads significantly.

  6. Engineering artificial redox chains by molecular 'Lego'.

    Science.gov (United States)

    Sadeghi, S J; Meharenna, Y T; Fantuzzi, A; Valetti, F; Gilardi, G

    2000-01-01

    This work reports on a novel approach for building artificial redox chains: the molecular 'Lego' approach. This exploits the scaffold of natural redox proteins by fusing together functional protein modules with the desired properties. The molecular 'Lego' mimics the natural molecular evolution that proceeded by modular assembly of genes/DNA segments. Non-physiological electron transfer partners, flavodoxin (fld) and cytochrome c553 (c553) from Desulfovibrio vulgaris and the haem domain of P450 BM3 (BMP) from Bacillus megaterium have been used as building blocks in different combinations to build artificial redox chains. The kinetic characterization of the electron transfer (ET) between the separate building blocks has been carried out. Under pseudo-first order conditions, a limiting ET rate, klim, of 0.48 +/- 0.05 s-1 and 43.77 +/- 2.18 s-1 and an apparent binding constant, Kapp, of 21 +/- 6 microM and 1.23 +/- 0.32 microM have been found for the fld/c553 and fld/BMP redox pairs, respectively. These results show that fld can be used as a module for transferring electrons to c553 and BMP. A 3D model of the fld/c553 and fld/BMP complexes was used to guide the construction of covalently linked assemblies via engineered disulfide bridges or by fusion of the relevant genes via an engineered loop. The first approach led to the construction, expression and characterization of the S35C and S64C mutants of fld and M23C and G51C mutants of c553. Although the redox potentials of the separate mutants were found to be the same as those of recombinant wild type proteins (-408 mV for the semiquinone/hydroquinone couple of fld and +32 mV for the c553), the c553 homo-dimers M23C-M23C and G51C-G51C were found to have redox potentials of +88 and +105 mV, respectively. These differences have been analysed in terms of exposure of the haem cofactors to the solvent, and these lead to some interesting questions on the redox potentials of the transient redox complexes in physiological

  7. Motion Synthesis of a Self-Steered Mobile Robot

    Science.gov (United States)

    Roseborrough, Michael; Phillips, Keith

    1987-02-01

    Until the late 1950's there was an almost exclusive use of graphical methods in the kinematic analysis and synthesis of mechanisms. With the increasing availability of high-speed digital computers there was a major reawakening of interest in a field con-sidered by many to be mature and dormant. Today the birth of advanced robotic systems has heightened the interest in applications of kinematic analysis and synthesis. This paper discusses the application of kinematics to the path planning model of a three wheeled, self-steering, mobile robot. The problem is formulated through a kinematic analysis of the path curvature and the synthesis of a set of equivalent linkages. The equivalent linkages facilitate a direct relationship between the path and the robot steering control mechanism. This is accomplished through the kinematic param-eters displacement, velocity and acceleration. The mathematical model is presented in a generalized format with the robot represented as a rigid body. Examples are shown which solve the problem of moving the robot through a crowded environment and arriving at its destination in a predetermined orientation.

  8. Needle Steering in 3-D Via Rapid Replanning

    Science.gov (United States)

    Patil, Sachin; Burgner, Jessica; Webster, Robert J.; Alterovitz, Ron

    2014-01-01

    Steerable needles have the potential to improve the effectiveness of needle-based clinical procedures such as biopsy and drug delivery by improving targeting accuracy and reaching previously inaccessible targets that are behind sensitive or impenetrable anatomical regions. We present a new needle steering system capable of automatically reaching targets in 3-D environments while avoiding obstacles and compensating for real-world uncertainties. Given a specification of anatomical obstacles and a clinical target (e.g., from preoperative medical images), our system plans and controls needle motion in a closed-loop fashion under sensory feedback to optimize a clinical metric. We unify planning and control using a new fast algorithm that continuously replans the needle motion. Our rapid replanning approach is enabled by an efficient sampling-based rapidly exploring random tree (RRT) planner that achieves orders-of-magnitude reduction in computation time compared with prior 3-D approaches by incorporating variable curvature kinematics and a novel distance metric for planning. Our system uses an electromagnetic tracking system to sense the state of the needle tip during the procedure. We experimentally evaluate our needle steering system using tissue phantoms and animal tissue ex vivo. We demonstrate that our rapid replanning strategy successfully guides the needle around obstacles to desired 3-D targets with an average error of less than 3 mm. PMID:25435829

  9. Electronically-Controlled Beam-Steering through Vanadium Dioxide Metasurfaces

    Science.gov (United States)

    Hashemi, Mohammed Reza M.; Yang, Shang-Hua; Wang, Tongyu; Sepúlveda, Nelson; Jarrahi, Mona

    2016-10-01

    Engineered metamaterials offer unique functionalities for manipulating the spectral and spatial properties of electromagnetic waves in unconventional ways. Here, we report a novel approach for making reconfigurable metasurfaces capable of deflecting electromagnetic waves in an electronically controllable fashion. This is accomplished by tilting the phase front of waves through a two-dimensional array of resonant metasurface unit-cells with electronically-controlled phase-change materials embedded inside. Such metasurfaces can be placed at the output facet of any electromagnetic radiation source to deflect electromagnetic waves at a desired frequency, ranging from millimeter-wave to far-infrared frequencies. Our design does not use any mechanical elements, external light sources, or reflectarrays, creating, for the first time, a highly robust and fully-integrated beam-steering device solution. We demonstrate a proof-of-concept beam-steering metasurface optimized for operation at 100 GHz, offering up to 44° beam deflection in both horizontal and vertical directions. Dynamic control of electromagnetic wave propagation direction through this unique platform could be transformative for various imaging, sensing, and communication applications, among others.

  10. Research on the Steering Strategy for Hydrogen Maser

    Science.gov (United States)

    Yin, D. S.; Zhao, S. H.; Gao, Y. P.

    2016-07-01

    In the master clock system, the local standard time UTC(k) with a better short-term stability will be generated, if the hydrogen maser is set as a frequency source of the master clock. But the hydrogen maser always exhibits an apparent frequency drift, thus its long-term stability gets poor with time, therefore the stability and accuracy of UTC(k) become worse. To solve this problem, we compare the performance of hydrogen maser with cesium clocks, and modify the time scale algorithm when the hydrogen maser is involved, we also propose a new steering strategy when hydrogen maser is used as the frequency source of master clock. We set up an experiment system and write programs, and finally the new steering strategy is testified with the laboratory data. Results show that when the hydrogen maser is involved in the atomic time scale calculation, the short-term frequency stability of reference time scale will be improved. Meanwhile, the local time UTC(k) has a better short-term frequency stability when the frequency source of the master clock uses hydrogen maser instead of cesium clock.

  11. Feeding behavior of steers fed a complete mixed ration.

    Science.gov (United States)

    Chase, L E; Wangsness, P J; Baumgardt, B R

    1976-11-01

    Feeding behavior of five Holstein steers fed a complete mixed ration was studied by use of individual, electronically controlled feeding behavior units. Both individual meal and daily behavioral parameters were measured. Number of meals, size of each individual meal, time spent eating, and intervals between meals were measured. Eating rates were then calculated. Diurnal feeding patterns were observed with 60.9% of the meals occurring between 0600 and 1800 h. For individual meals, body weight accounted for less than 30% of the variation in meal size. Average meal size was 414.5 g. Respective means for overall meal duration, actual meal duration, overall eating rate, and actual eating rate were 20.3 min, 13.7 min, 23.1 g/min, and 30.0 g/min. Meal size per body weight (g/kg or g/kg.75) was relatively constant during observation. Both increased eating rate and increased meal length were associated with larger meals. However, eating rate tended to plateau while meal length continued to increase with larger meals. Steers consumed 10.01 meals per day while total daily overall meal duration and actual meal duration were 220.9 and 156.4 min.

  12. Aeronautical satellite antenna steering using magnetic field sensors

    Science.gov (United States)

    Sydor, John; Dufour, Martial

    1993-01-01

    Designers of aeronautical satellite terminals are often faced with the problem of steering a directive antenna from an airplane or helicopter. This problem is usually solved by using aircraft orientation information derived from inertial sensors on-board the aircraft in combination with satellite ephemeris information calculated from geographic coordinates. This procedure works well but relies heavily on avionics that are external to the terminal. For the majority of small aircraft and helicopters which will form the bulk of future aeronautical satcom users, such avionics either do not exist or are difficult for the satellite terminal to interface with. At the Communications Research Center (CRC), work has been undertaken to develop techniques that use the geomagnetic field and satellite antenna pointing vectors (both of which are stationary in a local geographical area) to track the position of a satellite relative to a moving platform such as an aircraft. The performance of this technique is examined and a mathematical steering transformation is developed within this paper. Details are given regarding the experimental program that will be undertaken to test the concepts proposed herein.

  13. Stability Simulation of a Vehicle with Wheel Active Steering

    Directory of Open Access Journals (Sweden)

    Brabec Pavel

    2016-01-01

    Full Text Available This paper deals with the possibility of increasing the vehicle driving stability at a higher speed. One of the ways how to achieve higher stability is using the 4WS system. Mathematical description of vehicle general movement is a very complex task. For simulation, models which are aptly simplified are used. For the first approach, so-called single-truck vehicle model (often linear is usually used. For the simulation, we have chosen to extend the model into a two-truck one, which includes the possibility to input more vehicle parameters. Considering the 4WS system, it is possible to use a number of potential regulations. In our simulation model, the regulation system with compound coupling was used. This type of regulation turns the rear wheels depending on the input parameters of the system (steering angle of the front wheels and depending on the output moving quantities of the vehicle, most frequently the yaw rate. Criterion for compensation of lateral deflection centre of gravity angle is its zero value, or more precisely the zero value of its first-order derivative. Parameters and set-up of the simulation model were done in conjunction with the dSAPACE software. Reference performances of the vehicle simulation model were made through the defined manoeuvres. But the simulation results indicate that the rear-wheels steering can have a positive effect on the vehicle movement stability, especially when changing the driving direction at high speed.

  14. Reducing supplementation frequency for Nellore beef steers grazing tropical pastures

    Directory of Open Access Journals (Sweden)

    Roberta Carrilho Canesin

    2014-04-01

    Full Text Available Reduced supplementation frequency is a broadly applied management practice. Ruminants consuming low quality forages/pastures, supplemented less than once daily are able to maintain body weight gain (BWG, efficiency of use of dry matter, nitrogen and other nutrients, as compared with animals supplemented once daily. We evaluated the feeding behavior, dry matter intake (DMI, dry matter and organic matter digestibility (DMD and OMD, BWG, Longissimus muscle area and backfat depth of Nellore steers raised on Brachiaria brizantha cv. Marandu pastures during the dry season, with different supplementation patterns. Thirty six animals (338 ± 40.7 kg were distributed over nine paddocks according to a completely randomized design. Treatments were based on supplementation frequency: once daily (OD, once daily except Saturdays and Sundays (SS, or on alternate days (AD, at 1.0 %, 1.4 % and 2.0 % BW, respectively. Average total DMI accounted for 1.6 % BW day-1, with no effect of supplementation frequency. Supplementation frequency had no effect on BWG or grazing time during the day. There was no difference in Longissimus muscle area animals supplemented daily, SS and AD. The backfat depth was thinner in animals supplemented AD, but even in this case, it was within the standards considered satisfactory for a finishing steer. Reducing supplementation frequency seems a good option to lower labor costs without affecting feed efficiency or carcass quality in beef cattle grazing tropical pastures.

  15. Electronically-Controlled Beam-Steering through Vanadium Dioxide Metasurfaces

    Science.gov (United States)

    Hashemi, Mohammed Reza M.; Yang, Shang-Hua; Wang, Tongyu; Sepúlveda, Nelson; Jarrahi, Mona

    2016-01-01

    Engineered metamaterials offer unique functionalities for manipulating the spectral and spatial properties of electromagnetic waves in unconventional ways. Here, we report a novel approach for making reconfigurable metasurfaces capable of deflecting electromagnetic waves in an electronically controllable fashion. This is accomplished by tilting the phase front of waves through a two-dimensional array of resonant metasurface unit-cells with electronically-controlled phase-change materials embedded inside. Such metasurfaces can be placed at the output facet of any electromagnetic radiation source to deflect electromagnetic waves at a desired frequency, ranging from millimeter-wave to far-infrared frequencies. Our design does not use any mechanical elements, external light sources, or reflectarrays, creating, for the first time, a highly robust and fully-integrated beam-steering device solution. We demonstrate a proof-of-concept beam-steering metasurface optimized for operation at 100 GHz, offering up to 44° beam deflection in both horizontal and vertical directions. Dynamic control of electromagnetic wave propagation direction through this unique platform could be transformative for various imaging, sensing, and communication applications, among others. PMID:27739471

  16. Needle Steering in 3-D Via Rapid Replanning.

    Science.gov (United States)

    Patil, Sachin; Burgner, Jessica; Webster, Robert J; Alterovitz, Ron

    2014-08-01

    Steerable needles have the potential to improve the effectiveness of needle-based clinical procedures such as biopsy and drug delivery by improving targeting accuracy and reaching previously inaccessible targets that are behind sensitive or impenetrable anatomical regions. We present a new needle steering system capable of automatically reaching targets in 3-D environments while avoiding obstacles and compensating for real-world uncertainties. Given a specification of anatomical obstacles and a clinical target (e.g., from preoperative medical images), our system plans and controls needle motion in a closed-loop fashion under sensory feedback to optimize a clinical metric. We unify planning and control using a new fast algorithm that continuously replans the needle motion. Our rapid replanning approach is enabled by an efficient sampling-based rapidly exploring random tree (RRT) planner that achieves orders-of-magnitude reduction in computation time compared with prior 3-D approaches by incorporating variable curvature kinematics and a novel distance metric for planning. Our system uses an electromagnetic tracking system to sense the state of the needle tip during the procedure. We experimentally evaluate our needle steering system using tissue phantoms and animal tissue ex vivo. We demonstrate that our rapid replanning strategy successfully guides the needle around obstacles to desired 3-D targets with an average error of less than 3 mm.

  17. Monitoring and Steering of Large-Scale Distributed Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Geist, G.A.; Kohl, J.A.

    1999-09-01

    Oak Ridge National Laboratory is developing a state-of-the-art parallel application development system called CUMULVS, which allows scientists to easily incorporate interactive visualization, computational steering and fault tolerance into distributed software applications. The system is a valuable tool for many large scientific applications because it enables the scientist to visually monitor large data fields and remotely control parameters inside a running application. Collaborative monitoring is provided by allowing multiple researchers to simultaneously attach to a simulation, each controlling their own view of the same or different data fields within the simulation. By supporting steering of a simulation while it is running, CUMULVS provides the opportunity to accelerate the process of scientific discovery. CUMULVS also provides a simple mechanism to incorporate automatic checkpointing and heterogeneous task migration into large applications so that simulations can continue to run for weeks unattended. This paper will give an overview of the CUMULVS system and its capabilities, including several case histories. The status of the project is described with instructions on how to obtain the software.

  18. Redox regulation of Janus kinase: The elephant in the room.

    Science.gov (United States)

    Duhé, Roy J

    2013-10-01

    The redox regulation of Janus kinases (JAKs) is a complex subject. Due to other redox-sensitive kinases in the kinome, redox-sensitive phosphatases, and cellular antioxidant systems and reactive oxygen species (ROS) production systems, the net biological outcomes of oxidative stress on JAK-dependent signal transduction vary according to the specific biological system examined. This review begins with a discussion of the biochemical evidence for a cysteine-based redox switch in the catalytic domain of JAKs, proceeds to consider direct and indirect regulatory mechanisms involved in biological experiments, and ends with a discussion of the role(s) of redox regulation of JAKs in various diseases.

  19. Multi-targeted inhibition of tumor growth and lung metastasis by redox-sensitive shell crosslinked micelles loading disulfiram

    Science.gov (United States)

    Duan, Xiaopin; Xiao, Jisheng; Yin, Qi; Zhang, Zhiwen; Yu, Haijun; Mao, Shirui; Li, Yaping

    2014-03-01

    Metastasis, the main cause of cancer related deaths, remains the greatest challenge in cancer treatment. Disulfiram (DSF), which has multi-targeted anti-tumor activity, was encapsulated into redox-sensitive shell crosslinked micelles to achieve intracellular targeted delivery and finally inhibit tumor growth and metastasis. The crosslinked micelles demonstrated good stability in circulation and specifically released DSF under a reductive environment that mimicked the intracellular conditions of tumor cells. As a result, the DSF-loaded redox-sensitive shell crosslinked micelles (DCMs) dramatically inhibited cell proliferation, induced cell apoptosis and suppressed cell invasion, as well as impairing tube formation of HMEC-1 cells. In addition, the DCMs could accumulate in tumor tissue and stay there for a long time, thereby causing significant inhibition of 4T1 tumor growth and marked prevention in lung metastasis of 4T1 tumors. These results suggested that DCMs could be a promising delivery system in inhibiting the growth and metastasis of breast cancer.

  20. The Design of a Controller for the Steer-by-Wire System

    Science.gov (United States)

    Oh, Se-Wook; Chae, Ho-Chol; Yun, Seok-Chan; Han, Chang-Soo

    Drive-by-Wire (DBW) technologies improve conventional vehicle performance and a Steer-by-Wire (SBW) system is one of the DBW technologies. The control algorithm of the SBW system was designed in this paper. To verify the control algorithm, the SBW system is modeled using the bond graph method. The first aim of the control algorithm is controlling the steering wheel assist motor to make the real vehicle's steering feel and for a vehicle designer to adjust the steering feel as he finds necessary. Therefore, torque map is designed to determine the steering wheel reactive torque. The second aim is controlling the front wheel assist motor to improve vehicle's maneuverability and stability by using understeer and oversteer propensity of a vehicle. Furthermore, high performance control algorithm is proposed in this paper and Active Roll Stability Control (ARSC) method is designed as one of the high performance control algorithm.

  1. Robust PID Steering Control in Parameter Space for Highly Automated Driving

    Directory of Open Access Journals (Sweden)

    Mümin Tolga Emirler

    2014-01-01

    Full Text Available This paper is on the design of a parameter space based robust PID steering controller. This controller is used for automated steering in automated path following of a midsized sedan. Linear and nonlinear models of this midsized sedan are presented in the paper. Experimental results are used to validate the longitudinal and lateral dynamic models of this vehicle. This paper is on automated steering control and concentrates on the lateral direction of motion. The linear model is used to design a PID steering controller in parameter space that satisfies D-stability. The PID steering controller that is designed is used in a simulation study to illustrate the effectiveness of the proposed method. Simulation results for a circular trajectory and for a curved trajectory are presented and discussed in detail. This study is part of a larger research effort aimed at implementing highly automated driving in a midsized sedan.

  2. Effect of abomasal infusion of aspartate on nitrogen balance and plasma amino acids in Holstein steers.

    Science.gov (United States)

    Wessels, R H; Titgemeyer, E C

    1998-01-01

    We investigated the effect of abomasally infused aspartate (Asp) on N balance and plasma amino acids in steers. Four ruminally cannulated Holstein steers (180 kg) housed in metabolism crates were used in an experiment designed as a 4 x 3 Youden square. Steers received continuous abomasal infusions of water or water containing 40 or 80 g Asp/d. Steers were fed twice daily a diet containing 473 g/kg corn, 463 g/kg alfalfa hay and 52 g/kg soybean meal at levels near ad libitum intake. Abomasally infused Asp had no effect on N balance. Infusion of 80 g Asp/d increased (P < 0.05) plasma concentrations of Asp, glutamate and alanine. Metabolism of Asp by gut tissues probably prevented the large change in plasma concentration of Asp that seems necessary to trigger hormonal responses. We conclude that abomasal supplementation of steers with up to 80 g/d of Asp does not enhance performance.

  3. Analysis of Steering Knuckle of All Terrain Vehicles (ATV) Using Finite Element Analysis

    Science.gov (United States)

    Dusane, S. V.; Dipke, M. K.; Kumbhalkar, M. A.

    2016-09-01

    Steering knuckle is the most stress sustaining and critical component of All Terrain Vehicle (ATV). Steering knuckle is the pivot point of the steering and suspension system, which allows the front wheels to turn and also allow the movement of suspension arms motion. The light weight and high strength component is always in demanding for racecar application. Lightweight and optimized design of steering knuckle is proposed to use for a BAJA SAE INDIA off road racecar. Due to the failure in knuckle in terrain vehicle after some instances, it has to be modified for better performance. The 3D CAD model created by using CATIA V5 and static as well as model analysis carried out in ANSYS 12 to understand its behavior under operating conditions. All test for frame was carried out on aluminum alloys 6061-T6 & for spindle EN8. The paper discusses the FE analysis of existing and modified Steering Knuckle.

  4. High speed, high power one-dimensional beam steering from a 6-element optical phased array.

    Science.gov (United States)

    Huang, W Ronny; Montoya, Juan; Kansky, Jan E; Redmond, Shawn M; Turner, George W; Sanchez-Rubio, Antonio

    2012-07-30

    Beam steering at high speed and high power is demonstrated from a 6-element optical phased array using coherent beam combining (CBC) techniques. The steering speed, defined as the inverse of the time to required to sweep the beam across the steering range, is 40 MHz and the total power is 396 mW. The measured central lobe FWHM width is 565 μrad. High on-axis intensity is maintained periodically by phase-locking the array via a stochastic-parallel-gradient-descent (SPGD) algorithm. A master-oscillator-power-amplifier (MOPA) configuration is used where the amplifier array elements are semiconductor slab-coupled-optical-waveguide-amplifiers (SCOWAs). The beam steering is achieved by LiNbO(3) phase modulators; the phase-locking occurs by current adjustment of the SCOWAs. The system can be readily scaled to GHz steering speed and multiwatt-class output.

  5. One-way steering of optical fields via dissipation of an atomic reservoir

    Science.gov (United States)

    Rao, Shi; Hu, Xiangming; Li, Lingchao; Xu, Jun

    2016-11-01

    Einstein-Podolsky-Rosen (EPR) steering as a form of quantum correlation lies between entanglement and Bell nonlocality and exhibits an inherent asymmetry between two observers. We study EPR steering of two fields, which are generated via four-wave mixing processes and are entangled with each other due to the dissipation of the atomic reservoir. It is shown that the one-way steering happens from one mode to the other for different cavity decay rates and not too small cooperation parameters. Depending on the adiabatic and nonadiabatic conditions, the one-way steering occurs in a different detuning region when the cooperation parameters are relatively small. An increase in the cooperation parameters leads to an increase both in the parameter region and in the degree for the one-way steering. Finally we generalize the present scheme to the cases of the bright and/or collective fields.

  6. Redox signaling: Potential arbitrator of autophagy and apoptosis in therapeutic response.

    Science.gov (United States)

    Zhang, Lu; Wang, Kui; Lei, Yunlong; Li, Qifu; Nice, Edouard Collins; Huang, Canhua

    2015-12-01

    Redox signaling plays important roles in the regulation of cell death and survival in response to cancer therapy. Autophagy and apoptosis are discrete cellular processes mediated by distinct groups of regulatory and executioner molecules, and both are thought to be cellular responses to various stress conditions including oxidative stress, therefore controlling cell fate. Basic levels of reactive oxygen species (ROS) may function as signals to promote cell proliferation and survival, whereas increase of ROS can induce autophagy and apoptosis by damaging cellular components. Growing evidence in recent years argues for ROS that below detrimental levels acting as intracellular signal transducers that regulate autophagy and apoptosis. ROS-regulated autophagy and apoptosis can cross-talk with each other. However, how redox signaling determines different cell fates by regulating autophagy and apoptosis remains unclear. In this review, we will focus on understanding the delicate molecular mechanism by which autophagy and apoptosis are finely orchestrated by redox signaling and discuss how this understanding can be used to develop strategies for the treatment of cancer.

  7. Redox-control of the alarmin, Interleukin-1α

    Directory of Open Access Journals (Sweden)

    Donald A. McCarthy

    2013-01-01

    Full Text Available The pro-inflammatory cytokine Interleukin-1α (IL-1α has recently emerged as a susceptibility marker for a wide array of inflammatory diseases associated with oxidative stress including Alzheimer's, arthritis, atherosclerosis, diabetes and cancer. In the present study, we establish that expression and nuclear localization of IL-1α are redox-dependent. Shifts in steady-state H2O2 concentrations (SS-[H2O2] resulting from enforced expression of manganese superoxide dismutase (SOD2 drive IL-1α mRNA and protein expression. The redox-dependent expression of IL-1α is accompanied by its increased nuclear localization. Both IL-1α expression and its nuclear residency are abrogated by catalase co-expression. Sub-lethal doses of H2O2 also cause IL-1α nuclear localization. Mutagenesis revealed IL-1α nuclear localization does not involve oxidation of cysteines within its N terminal domain. Inhibition of the processing enzyme calpain prevents IL-1α nuclear localization even in the presence of H2O2. H2O2 treatment caused extracellular Ca2+ influx suggesting oxidants may influence calpain activity indirectly through extracellular Ca2+ mobilization. Functionally, as a result of its nuclear activity, IL-1α overexpression promotes NF-kB activity, but also interacts with the histone acetyl transferase (HAT p300. Together, these findings demonstrate a mechanism by which oxidants impact inflammation through IL-1α and suggest that antioxidant-based therapies may prove useful in limiting inflammatory disease progression.

  8. Postgraze assessment of toxicosis symptoms for steers grazed on toxic endophyte-infected tall fescue pasture.

    Science.gov (United States)

    Aiken, G E; Klotz, J L; Johnson, J M; Strickland, J R; Schrick, F N

    2013-12-01

    A 2-yr pen experiment was conducted using 12 different crossbred Angus steers each year to determine if short-term changes in prolactin concentrations, body temperature, and vasoconstriction reflect recovery from fescue toxicosis after steers that previously grazed toxic endophyte (Neotyphodium coenophialum)-infected Kentucky 31 tall fescue [Lolium arundinaceum (Schreb.) Darbysh] are placed on nontoxic feed. Groups of 6 steers from toxic endophyte-infected and endophyte-free tall fescue grazing treatments were blocked by BW for assignment to pens as a randomized complete block design with 2 replications. Two environments were implemented by initiating the experiment on 18 August in yr 1 and on 8 September in yr 2 for durations of 30 and 21 d, respectively. Rectal temperatures were recorded, jugular blood was collected for assaying serum prolactin, and cross sections of the caudal artery were ultrasonically imaged at selected time points to evaluate temporal changes in the response variables. Rectal temperatures in steers on the toxic endophyte pasture treatment declined (P 0.10) to those on endophyte-free treatment on d 30 in yr 1 and by d 15 in yr 2. Prolactin concentrations in steers on the toxic endophyte pasture treatment showed curvilinear increases (P 0.10) to steers on the endophyte-free treatment by d 15 in yr 1 and by d 10 in yr 2. Luminal areas of the caudal artery in toxic endophyte steers were less (P endophyte-free steers across all dates in both years. Results indicated that rectal temperatures in steers after they are removed from toxic fescue may decrease over time, but temporal changes in rectal temperatures could be affected more by prevailing ambient temperatures than by actual mitigation of fescue toxicosis. Prolactin concentrations in steers after they are removed from toxic endophyte tall fescue can increase and stabilize in less than 2 wk, but alkaloid-induced vasoconstriction that causes a vulnerability to severe heat stress is not

  9. Anion permselective membrane. [For redox fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, S.S.; Hodgdon, R.B.

    1978-01-01

    Experimental anion permeselective membranes were improved and characterized for use as separators in a chemical redox, power storage cell being developed at the NASA Lewis Research Center. The goal of minimal Fe/sup +3/ ion transfer was achieved for each candidate membrane system. Minimal membrane resistivity was demonstrated by reduction of film thickness using synthetic backing materials but usefulness of thin membranes was limited by the scarcity of compatible fabrics. The most durable and useful backing fabrics were modacrylics. One membrane, a copolymer of 4 vinylpyridine and vinyl benzylchloride was outstanding in overall electrochemical and physical properties. Long term (1000 hrs) membrane chemical and thermal durability in redox environment was shown by three candidate polymers and two membranes. The remainder had good durability at ambient temperature. Manufacturing capability was demonstrated for large scale production of membrane sheets 5.5 ft/sup 2/ in area for two candidate systems.

  10. Cost projections for Redox Energy storage systems

    Science.gov (United States)

    Michaels, K.; Hall, G.

    1980-01-01

    A preliminary design and system cost analysis was performed for the redox energy storage system. A conceptual design and cost estimate was prepared for each of two energy applications: (1) electric utility 100-MWh requirement (10-MW for ten hours) for energy storage for utility load leveling application, and (2) a 500-kWh requirement (10-kW for 50 hours) for use with a variety of residential or commercial applications, including stand alone solar photovoltaic systems. The conceptual designs were based on cell performance levels, system design parameters, and special material costs. These data were combined with estimated thermodynamic and hydraulic analysis to provide preliminary system designs. Results indicate that the redox cell stack to be amenable to mass production techniques with a relatively low material cost.

  11. Cooperative redox activation for carbon dioxide conversion

    Science.gov (United States)

    Lian, Zhong; Nielsen, Dennis U.; Lindhardt, Anders T.; Daasbjerg, Kim; Skrydstrup, Troels

    2016-12-01

    A longstanding challenge in production chemistry is the development of catalytic methods for the transformation of carbon dioxide into useful chemicals. Silane and borane promoted reductions can be fined-tuned to provide a number of C1-building blocks under mild conditions, but these approaches are limited because of the production of stoichiometric waste compounds. Here we report on the conversion of CO2 with diaryldisilanes, which through cooperative redox activation generate carbon monoxide and a diaryldisiloxane that actively participate in a palladium-catalysed carbonylative Hiyama-Denmark coupling for the synthesis of an array of pharmaceutically relevant diarylketones. Thus the disilane reagent not only serves as the oxygen abstracting agent from CO2, but the silicon-containing `waste', produced through oxygen insertion into the Si-Si bond, participates as a reagent for the transmetalation step in the carbonylative coupling. Hence this concept of cooperative redox activation opens up for new avenues in the conversion of CO2.

  12. Progress of all vanadium redox flow batteries

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Aresearch team headed by Prof.ZHANG Huamin from the CAS Dalian Institute of Chemical Physics has made important progress in the research and development of a LED screen demo system powered by vanadium redox flow batteries (VRB).The system has operated continuously for over one year without any malfunction.So far,the total running time is up to 11,000 hours.

  13. Dismutación en equilibrios redox

    OpenAIRE

    Milla González, Miguel

    2011-01-01

    Se explica mediante animaciones interactivas el proceso de dismutación de una especie en equilibrios de óxido-reducción, tomando en consideración los valores de los potenciales normales de los pares redox involucrados. Se muestra asimismo la influencia que presentan las reacciones protolíticas, de complejación y de precipitación en los procesos de dismutación con algunos ejemplos de interés.

  14. Proterozoic ocean redox and biogeochemical stasis

    Science.gov (United States)

    Reinhard, Christopher T.; Planavsky, Noah J.; Robbins, Leslie J.; Partin, Camille A.; Gill, Benjamin C.; Lalonde, Stefan V.; Bekker, Andrey; Konhauser, Kurt O.; Lyons, Timothy W.

    2013-01-01

    The partial pressure of oxygen in Earth’s atmosphere has increased dramatically through time, and this increase is thought to have occurred in two rapid steps at both ends of the Proterozoic Eon (∼2.5–0.543 Ga). However, the trajectory and mechanisms of Earth’s oxygenation are still poorly constrained, and little is known regarding attendant changes in ocean ventilation and seafloor redox. We have a particularly poor understanding of ocean chemistry during the mid-Proterozoic (∼1.8–0.8 Ga). Given the coupling between redox-sensitive trace element cycles and planktonic productivity, various models for mid-Proterozoic ocean chemistry imply different effects on the biogeochemical cycling of major and trace nutrients, with potential ecological constraints on emerging eukaryotic life. Here, we exploit the differing redox behavior of molybdenum and chromium to provide constraints on seafloor redox evolution by coupling a large database of sedimentary metal enrichments to a mass balance model that includes spatially variant metal burial rates. We find that the metal enrichment record implies a Proterozoic deep ocean characterized by pervasive anoxia relative to the Phanerozoic (at least ∼30–40% of modern seafloor area) but a relatively small extent of euxinic (anoxic and sulfidic) seafloor (less than ∼1–10% of modern seafloor area). Our model suggests that the oceanic Mo reservoir is extremely sensitive to perturbations in the extent of sulfidic seafloor and that the record of Mo and chromium enrichments through time is consistent with the possibility of a Mo–N colimited marine biosphere during many periods of Earth’s history. PMID:23515332

  15. Proterozoic ocean redox and biogeochemical stasis.

    Science.gov (United States)

    Reinhard, Christopher T; Planavsky, Noah J; Robbins, Leslie J; Partin, Camille A; Gill, Benjamin C; Lalonde, Stefan V; Bekker, Andrey; Konhauser, Kurt O; Lyons, Timothy W

    2013-04-02

    The partial pressure of oxygen in Earth's atmosphere has increased dramatically through time, and this increase is thought to have occurred in two rapid steps at both ends of the Proterozoic Eon (∼2.5-0.543 Ga). However, the trajectory and mechanisms of Earth's oxygenation are still poorly constrained, and little is known regarding attendant changes in ocean ventilation and seafloor redox. We have a particularly poor understanding of ocean chemistry during the mid-Proterozoic (∼1.8-0.8 Ga). Given the coupling between redox-sensitive trace element cycles and planktonic productivity, various models for mid-Proterozoic ocean chemistry imply different effects on the biogeochemical cycling of major and trace nutrients, with potential ecological constraints on emerging eukaryotic life. Here, we exploit the differing redox behavior of molybdenum and chromium to provide constraints on seafloor redox evolution by coupling a large database of sedimentary metal enrichments to a mass balance model that includes spatially variant metal burial rates. We find that the metal enrichment record implies a Proterozoic deep ocean characterized by pervasive anoxia relative to the Phanerozoic (at least ∼30-40% of modern seafloor area) but a relatively small extent of euxinic (anoxic and sulfidic) seafloor (less than ∼1-10% of modern seafloor area). Our model suggests that the oceanic Mo reservoir is extremely sensitive to perturbations in the extent of sulfidic seafloor and that the record of Mo and chromium enrichments through time is consistent with the possibility of a Mo-N colimited marine biosphere during many periods of Earth's history.

  16. Investigation of Photoelectrode Redox Polymer Junctions

    Science.gov (United States)

    2007-11-02

    used for the cyclic voltammetry scans. RESULTS AND DISCUSSION Cell Preparatton Solid-state PEC cells were fabricated by introducing .05ml of a solution...Electrochemical measurements were performed using potentiostatic control provided by either a Stonehart Associates BC 1200 or a Wenking LT 78 poten- tiostat...ELH bulb. Light intensities were measured with an Eppley 8-48 pyranometer. Cyclic voltammograms on the redox couples were run in acetonitrile S

  17. X-ray voltabsorptometry on redox proteins

    Energy Technology Data Exchange (ETDEWEB)

    Ascone, Isabella [Dipartimento di Fisica, Universita di Roma ' La Sapienza' , P.le A. Moro 5, 00185 Rome (Italy) and LURE/CNRS Centre Universitaire Paris-Sud, bat. 209 D, B.P. 34, 91898 Orsay Cedex (France)]. E-mail: i.ascone@caspur.it; Zamponi, Silvia [Dipartimento di Scienze Chimiche, Universita di Camerino, Via S. Agostino 1, 62032 Camerino (Italy); Cognigni, Andrea [LURE/CNRS Centre Universitaire Paris-Sud, bat. 209 D, B.P. 34, 91898 Orsay Cedex (France); Marmocchi, Franco [Dipartimento di Biologia Molecolare, Cellulare e Animale, Universita di Camerino, Via Camerini, 1 Camerino (Italy); Marassi, Roberto [Dipartimento di Scienze Chimiche, Universita di Camerino, Via S. Agostino 1, 62032 Camerino (Italy)

    2005-04-15

    Biological X-ray absorption spectroscopy (BioXAS) is able to describe the metal environment in a metalloprotein and is sensitive to metal oxidation state. Coupling of BioXAS and electrochemistry permits the characterization of different oxidation states and avoids uncontrolled protein redox state changes due to X-ray beam irradiation. XAS spectroelectrochemistry requires electrochemical cells specifically designed to meet the requirements of both XAS measurements and electrochemical effectiveness in potential control. In this context, this paper describes a new cell tested with different types of working electrodes developed for BioXAS, in particular for in situ studies of redox proteins. The XAS electrochemical measurements of a relatively high-molecular-weight protein (Cu,Zn superoxide dismutase) for which it is difficult to observe direct electrochemistry have been achieved. New working electrodes, capable of fast and unmediated electron transfer, are described. The cell permits to isolate protein redox states and to measure X-ray absorption intensity during a potential scan (X-ray voltabsorptometry)

  18. Measurement of Redox Potential in Nanoecotoxicological Investigations

    Directory of Open Access Journals (Sweden)

    Ratna Tantra

    2012-01-01

    Full Text Available Redox potential has been identified by the Organisation for Economic Co-operation and Development (OECD as one of the parameters that should be investigated for the testing of manufactured nanomaterials. There is still some ambiguity concerning this parameter, i.e., as to what and how to measure, particularly when in a nanoecotoxicological context. In this study the redox potentials of six nanomaterials (either zinc oxide (ZnO or cerium oxide (CeO2 dispersions were measured using an oxidation-reduction potential (ORP electrode probe. The particles under testing differed in terms of their particle size and dispersion stability in deionised water and in various ecotox media. The ORP values of the various dispersions and how they fluctuate relative to each other are discussed. Results show that the ORP values are mainly governed by the type of liquid media employed, with little contributions from the nanoparticles. Seawater was shown to have reduced the ORP value, which was attributed to an increase in the concentration of reducing agents such as sulphites or the reduction of dissolved oxygen concentration. The lack of redox potential value contribution from the particles themselves is thought to be due to insufficient interaction of the particles at the Pt electrode of the ORP probe.

  19. Redox Regulation in Amyotrophic Lateral Sclerosis

    Directory of Open Access Journals (Sweden)

    Sonam Parakh

    2013-01-01

    Full Text Available Amyotrophic lateral sclerosis (ALS is a neurodegenerative disease that results from the death of upper and lower motor neurons. Due to a lack of effective treatment, it is imperative to understand the underlying mechanisms and processes involved in disease progression. Regulations in cellular reduction/oxidation (redox processes are being increasingly implicated in disease. Here we discuss the possible involvement of redox dysregulation in the pathophysiology of ALS, either as a cause of cellular abnormalities or a consequence. We focus on its possible role in oxidative stress, protein misfolding, glutamate excitotoxicity, lipid peroxidation and cholesterol esterification, mitochondrial dysfunction, impaired axonal transport and neurofilament aggregation, autophagic stress, and endoplasmic reticulum (ER stress. We also speculate that an ER chaperone protein disulphide isomerase (PDI could play a key role in this dysregulation. PDI is essential for normal protein folding by oxidation and reduction of disulphide bonds, and hence any disruption to this process may have consequences for motor neurons. Addressing the mechanism underlying redox regulation and dysregulation may therefore help to unravel the molecular mechanism involved in ALS.

  20. A redox-mediated Kemp eliminase

    Science.gov (United States)

    Li, Aitao; Wang, Binju; Ilie, Adriana; Dubey, Kshatresh D.; Bange, Gert; Korendovych, Ivan V.; Shaik, Sason; Reetz, Manfred T.

    2017-01-01

    The acid/base-catalysed Kemp elimination of 5-nitro-benzisoxazole forming 2-cyano-4-nitrophenol has long served as a design platform of enzymes with non-natural reactions, providing new mechanistic insights in protein science. Here we describe an alternative concept based on redox catalysis by P450-BM3, leading to the same Kemp product via a fundamentally different mechanism. QM/MM computations show that it involves coordination of the substrate's N-atom to haem-Fe(II) with electron transfer and concomitant N–O heterolysis liberating an intermediate having a nitrogen radical moiety Fe(III)–N· and a phenoxyl anion. Product formation occurs by bond rotation and H-transfer. Two rationally chosen point mutations cause a notable increase in activity. The results shed light on the prevailing mechanistic uncertainties in human P450-catalysed metabolism of the immunomodulatory drug leflunomide, which likewise undergoes redox-mediated Kemp elimination by P450-BM3. Other isoxazole-based pharmaceuticals are probably also metabolized by a redox mechanism. Our work provides a basis for designing future artificial enzymes. PMID:28348375

  1. Redox regulation in amyotrophic lateral sclerosis.

    Science.gov (United States)

    Parakh, Sonam; Spencer, Damian M; Halloran, Mark A; Soo, Kai Y; Atkin, Julie D

    2013-01-01

    Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that results from the death of upper and lower motor neurons. Due to a lack of effective treatment, it is imperative to understand the underlying mechanisms and processes involved in disease progression. Regulations in cellular reduction/oxidation (redox) processes are being increasingly implicated in disease. Here we discuss the possible involvement of redox dysregulation in the pathophysiology of ALS, either as a cause of cellular abnormalities or a consequence. We focus on its possible role in oxidative stress, protein misfolding, glutamate excitotoxicity, lipid peroxidation and cholesterol esterification, mitochondrial dysfunction, impaired axonal transport and neurofilament aggregation, autophagic stress, and endoplasmic reticulum (ER) stress. We also speculate that an ER chaperone protein disulphide isomerase (PDI) could play a key role in this dysregulation. PDI is essential for normal protein folding by oxidation and reduction of disulphide bonds, and hence any disruption to this process may have consequences for motor neurons. Addressing the mechanism underlying redox regulation and dysregulation may therefore help to unravel the molecular mechanism involved in ALS.

  2. Membrane development for vanadium redox flow batteries.

    Science.gov (United States)

    Schwenzer, Birgit; Zhang, Jianlu; Kim, Soowhan; Li, Liyu; Liu, Jun; Yang, Zhenguo

    2011-10-17

    Large-scale energy storage has become the main bottleneck for increasing the percentage of renewable energy in our electricity grids. Redox flow batteries are considered to be among the best options for electricity storage in the megawatt range and large demonstration systems have already been installed. Although the full technological potential of these systems has not been reached yet, currently the main problem hindering more widespread commercialization is the high cost of redox flow batteries. Nafion, as the preferred membrane material, is responsible for about 11% of the overall cost of a 1 MW/8 MWh system. Therefore, in recent years two main membrane related research threads have emerged: 1) chemical and physical modification of Nafion membranes to optimize their properties with regard to vanadium redox flow battery (VRFB) application; and 2) replacement of the Nafion membranes with different, less expensive materials. This review summarizes the underlying basic scientific issues associated with membrane use in VRFBs and presents an overview of membrane-related research approaches aimed at improving the efficiency of VRFBs and making the technology cost-competitive. Promising research strategies and materials are identified and suggestions are provided on how materials issues could be overcome.

  3. Redox alters yellow dragonflies into red.

    Science.gov (United States)

    Futahashi, Ryo; Kurita, Ryoji; Mano, Hiroaki; Fukatsu, Takema

    2012-07-31

    Body color change associated with sexual maturation--so-called nuptial coloration--is commonly found in diverse vertebrates and invertebrates, and plays important roles for their reproductive success. In some dragonflies, whereas females and young males are yellowish in color, aged males turn vivid red upon sexual maturation. The male-specific coloration plays pivotal roles in, for example, mating and territoriality, but molecular basis of the sex-related transition in body coloration of the dragonflies has been poorly understood. Here we demonstrate that yellow/red color changes in the dragonflies are regulated by redox states of epidermal ommochrome pigments. Ratios of reduced-form pigments to oxidized-form pigments were significantly higher in red mature males than yellow females and immature males. The ommochrome pigments extracted from the dragonflies changed color according to redox conditions in vitro: from red to yellow in the presence of oxidant and from yellow to red in the presence of reductant. By injecting the reductant solution into live insects, the yellow-to-red color change was experimentally reproduced in vivo in immature males and mature females. Discontinuous yellow/red mosaicism was observed in body coloration of gynandromorphic dragonflies, suggesting a cell-autonomous regulation over the redox states of the ommochrome pigments. Our finding extends the mechanical repertoire of pigment-based body color change in animals, and highlights an impressively simple molecular mechanism that regulates an ecologically important color trait.

  4. Tuning of redox regulatory mechanisms, reactive oxygen species and redox homeostasis under salinity stress

    Directory of Open Access Journals (Sweden)

    Hossain eSazzad

    2016-05-01

    Full Text Available Soil salinity is a crucial environmental constraint which limits biomass production at many sites on a global scale. Saline growth conditions cause osmotic and ionic imbalances, oxidative stress and perturb metabolism, e.g. the photosynthetic electron flow. The plant ability to tolerate salinity is determined by multiple biochemical and physiological mechanisms protecting cell functions, in particular by regulating proper water relations and maintaining ion homeostasis. Redox homeostasis is a fundamental cell property. Its regulation includes control of reactive oxygen species (ROS generation, sensing deviation from and readjustment of the cellular redox state. All these redox related functions have been recognized as decisive factors in salinity acclimation and adaptation. This review focuses on the core response of plants to overcome the challenges of salinity stress through regulation of ROS generation and detoxification systems and to maintain redox homeostasis. Emphasis is given to the role of NADH oxidase (RBOH, alternative oxidase (AOX, the plastid terminal oxidase (PTOX and the malate valve with the malate dehydrogenase isoforms under salt stress. Overwhelming evidence assigns an essential auxiliary function of ROS and redox homeostasis to salinity acclimation of plants.

  5. Growth hormone secretion and clearance rates in growing beef steers implanted with estrogenic anabolic compounds.

    Science.gov (United States)

    Gopinath, R; Kitts, W D

    1984-01-01

    The effect of estrogenic anabolic compounds on the kinetic parameters of metabolism of growth hormone (GH) was studied in growing beef steers. Twenty-four beef steers were randomly placed into four groups and assigned to one of the following four treatment groups: zeranol, diethylstilbestrol (DES), Synovex-S and an unimplanted control. GH metabolism was studied from eight steers on day 20 following the implantation of anabolic compounds. The animals were rapidly injected with a solution of bGH (NIH-GH-B18) and the disappearance of injected GH from the plasma was monitored up to 120 min following the injection. The plasma GH disappearance curve displayed an initial rapid phase lasting 5 min and a slow disappearance phase lasting 42 min; the fractional turnover rate from the two compartments were 0.167 and 0.017 min-1, respectively. The average volume of distribution of GH in steers was 6% of the body weight. Mean values of metabolic clearance and secretion rates of GH in steers were 21 liters/h and 252 micrograms/h or 74.5 ml/kg/h and 0.91 microgram/kg/h, respectively. Steers implanted with anabolic compounds gained more rapidly (P less than 0.05) than the controls. Plasma basal GH concentration appeared to be higher in all the implanted than in the control steers. The secretion rate of GH was increased (P less than 0.05) in steers implanted with anabolic compounds when compared to control steers. The secretion rate (microgram/kg/h) was about 96% (P less than 0.05), 107% (P less than 0.05) and 81% (P less than 0.05) higher in steers implanted with DES, zeranol and Synovex-S, respectively, than in the control steers. All the compounds studied were equally effective in increasing the secretion of GH on day 20 following their implantation. Metabolic clearance rate of GH was not affected by anabolic compound implantation in steers. There was, however, a slight reduction in metabolic clearance rate due to DES and a slight elevation due to zeranol and Synovex-S when

  6. CANCER

    Directory of Open Access Journals (Sweden)

    N. Kavoussi

    1973-09-01

    Full Text Available There are many carcinogenetic elements in industry and it is for this reason that study and research concerning the effect of these materials is carried out on a national and international level. The establishment and growth of cancer are affected by different factors in two main areas:-1 The nature of the human or animal including sex, age, point and method of entry, fat metabolism, place of agglomeration of carcinogenetic material, amount of material absorbed by the body and the immunity of the body.2 The different nature of the carcinogenetic material e.g. physical, chemical quality, degree of solvency in fat and purity of impurity of the element. As the development of cancer is dependent upon so many factors, it is extremely difficult to determine whether a causative element is principle or contributory. Some materials are not carcinogenetic when they are pure but become so when they combine with other elements. All of this creates an industrial health problem in that it is almost impossible to plan an adequate prevention and safety program. The body through its system of immunity protects itself against small amounts of carcinogens but when this amount increases and reaches a certain level the body is not longer able to defend itself. ILO advises an effective protection campaign against cancer based on the Well –equipped laboratories, Well-educated personnel, the establishment of industrial hygiene within factories, the regular control of safety systems, and the implementation of industrial health principles and research programs.

  7. Characterisation of the Redox Sensitive NMDA Receptor

    KAUST Repository

    Alzahrani, Ohood

    2016-05-01

    Glucose entry into the brain and its subsequent metabolism to L-lactate, regulated by astrocytes, plays a major role in synaptic plasticity and memory formation. A recent study has shown that L-lactate produced by the brain upon stimulation of glycolysis, and glycogen-derived L-lactate from astrocytes and its transport into neurons, is crucial for memory formation. A recent study revealed the molecular mechanisms that underlie the role of L-lactate in neuronal plasticity and long-term memory formation. L-lactate was shown to induce a cascade of molecular events via modulation of redox-sensitive N-Methyl-D-aspartate (NMDA) receptor activity that was mimicked by nicotinamide adenine dinucleotide hydride (NADH) co-enzyme. This indicated that changes in cellular redox state, following L-lactate transport inside the cells and its subsequent metabolism, production of NADH, and favouring a reduced state are the key effects of L-lactate. Therefore, we are investigating the role of L-lactate in modulating NMDA receptor function via redox modulatory sites. Accordingly, crucial redox-sensitive cysteine residues, Cys320 and Cys87, of the NR2A NMDA receptor subunit are mutated using site-directed mutation, transfected, and expressed in HEK293 cells. This cellular system will then be used to characterise and monitor its activity upon Llactate stimulation, compared to the wild type. This will be achieved by calcium imaging, using fluorescent microscopy. Our data shows that L-lactate potentiated NMDA receptor activity and increased intracellular calcium influx in NR1/NR2A wild type compared to the control condition (WT NR1/NR2A perfused with (1μM) glutamate and (1μM) glycine agonist only), showing faster response initiation and slower decay rate of the calcium signal to the baseline. Additionally, stimulating with L-lactate associated with greater numbers of cells having high fluorescent intensity (peak amplitude) compared to the control. Furthermore, L-lactate rescued the

  8. Redox Enzymes of Red Beetroot Vacuoles (Beta vulgaris L.

    Directory of Open Access Journals (Sweden)

    E.V. Pradedova

    2014-12-01

    Full Text Available Years of research have shown that some of the redox elements (enzymes, coenzymes, and co-substrate are isolated from each other kinetic and spatial manner (compartmentalization in the eukaryotic cells. The redox elements forming the "highly" and "widely" specialized redox system are found in all cell structures: mitochondria, plastids, peroxisomes, apoplast, nucleus etc. In recent years the active involvement of the central vacuole in the maintenance of the plant cell redox homeostasis is discussed, actually the information about the vacuolar redox system is very small. The high-priority redox processes and "redox-specialization" of the vacuolar compartment are not known. We have begun a study of red beet-root vacuole redox systems (Beta vulgaris L. and have identified redox enzymes such as: phenol peroxidase (EC 1.11.1.7, superoxide dismutase (EC 1.15.1.1 and glutathione reductase (EC 1.8.1.7. This paper presents some of the characteristics of these enzymes and considers the probable ways of their functioning in vacuolar redox chains.

  9. Steering Law Controlling the Constant Speeds of Control Moment Gyros

    Science.gov (United States)

    KOYASAKO, Y.; TAKAHASHI, M.

    2016-09-01

    To enable the agile control of satellites, using control moment gyros (CMGs) has become increasingly necessary because of their ability to generate large amounts of torque. However, CMGs have a singularity problem whereby the torque by the CMGs degenerates from three dimensions to two dimensions, affecting spacecraft attitude control performance. This study proposes a new steering control law for CMGs by controlling the constant speed of a CMG. The proposed method enables agile attitude changes, according to the required task, by managing the total angular momentum of the CMGs by considering the distance to external singularities. In the proposed method, the total angular momentum is biased in a specific direction and the angular momentum envelope is extended. The design method can increase the net angular momentum of CMGs which can be exchanged with the satellite. The effectiveness of the proposed method is demonstrated by numerical simulations.

  10. Steered molecular dynamics simulations of protein-ligand interactions

    Institute of Scientific and Technical Information of China (English)

    XU; Yechun; SHEN; Jianhua; LUO; Xiaomin; SHEN; Xu; CHEN; Ka

    2004-01-01

    Studies of protein-ligand interactions are helpful to elucidating the mechanisms of ligands, providing clues for rational drug design. The currently developed steered molecular dynamics (SMD) is a complementary approach to experimental techniques in investigating the biochemical processes occurring at microsecond or second time scale, thus SMD may provide dynamical and kinetic processes of ligand-receptor binding and unbinding, which cannot be accessed by the experimental methods. In this article, the methodology of SMD is described, and the applications of SMD simulations for obtaining dynamic insights into protein-ligand interactions are illustrated through two of our own examples. One is associated with the simulations of binding and unbinding processes between huperzine A and acetylcholinesterase, and the other is concerned with the unbinding process of α-APA from HIV-1 reverse transcriptase.

  11. A self-steering close-talking microphone array

    Institute of Scientific and Technical Information of China (English)

    PENG Ke; YANG Xinfeng; XU Boling

    2005-01-01

    For communication in extremely noisy environments, close-talking microphone arrays are useful. Differential microphone array systems possessing excellent nearfield directivity and strong farfield-noise reduction capability are very suitable for close-talking situations. In order to improve the focusing effect at the desired bearing in the nearfield, we propose a novel self-steering system of closetalking arrays with the first-order differential sub-arrays in this paper. Calculations of directivity patterns and directivity factors show that when a kind of optimized beamforming technique is adopted even small arrays with a focusing configuration will exhibit a satisfactory nearfield directivity which is electronically steerable within a specific range. The superiority of the proposed array system is verified by experiments with real acoustic data.

  12. Steering optical comb frequency by rotating polarization state

    CERN Document Server

    Zhang, Y; Zhang, X F; Zhang, L; Han, W; Guo, W; Jiang, H; Zhang, S

    2016-01-01

    Optical frequency combs, with precise control of repetition rate and carrier-envelope-offset frequency, have revolutionized many fields, such as fine optical spectroscopy, optical frequency standards, ultra-fast science research, ultra-stable microwave generation and precise ranging measurement. However, existing high bandwidth frequency control methods have small dynamic range, requiring complex hybrid control techniques. To overcome this limitation, we develop a new approach, where a home-made intra-cavity electro-optic modulator tunes polarization state of laser signal rather than only optical length of the cavity, to steer frequencies of a nonlinear-polarization-rotation mode-locked laser. By taking advantage of birefringence of the whole cavity, this approach results in not only broadband but also relative large-dynamic frequency control. Experimental results show that frequency control dynamic range increase at least one order in comparison with the traditional intra-cavity electro-optic modulator techn...

  13. Beam steering and impedance matching of plasmonic horn nanoantennas

    Science.gov (United States)

    Afridi, Adeel; Kocabaş, Şükrü Ekin

    2016-10-01

    In this paper, we study a plasmonic horn nanoantenna on a metal-backed substrate. The horn nanoantenna structure consists of a two-wire transmission line (TWTL) flared at the end. We analyze the effect of the substrate thickness on the nanoantenna's radiation pattern, and demonstrate beam steering in a broad range of elevation angles. Furthermore, we analyze the effect of the ground plane on the impedance matching between the antenna and the TWTL, and observe that the ground plane increases the back reflection into the waveguide. To reduce the reflection, we develop a transmission line model to design an impedance matching section which leads to 99.75% power transmission to the nanoantenna.

  14. Steering artificial nanoscale swimmers using teardrop shaped posts

    Science.gov (United States)

    Davies Wykes, Megan; Zhong, Xiao; Adachi, Takiji; Liu, Yanpeng; Tong, Jiajun; Ristroph, Leif; Ward, Michael; Zhang, Jun; Shelley, Michael

    2016-11-01

    Microorganisms use various strategies to bias their swimming to achieve long-time directed motion against a flow, against gravity, or up a chemical gradient. To make use of artificial swimmers for transporting cargo, to separate swimming particles from diffusing ones, or to concentrate a solution of motile particles, ways of steering such swimmers are required. We make use of the attraction of artificial bi-metallic swimmers to vertical walls to direct their long-time motion. We will describe how these swimmers are attracted to the surface of teardrop-shaped posts and leave preferentially at regions of higher curvature. We use this understanding to interpret their behavior when interacting with arrays of teardrop-shaped posts. This work was supported partially by the Materials Research Science and Engineering Center (MRSEC) program of the National Science Foundation under Award Number DMR-1420073.

  15. Laser beam steering approaches for microstructuring of copper layers

    Science.gov (United States)

    Mur, Jaka; Podobnik, Boštjan; Poberaj, Igor

    2017-02-01

    We have investigated the process of copper layer ablation with a tightly focused Q-switched 532 nm laser. Focusing 40 ns long laser pulses to a micrometer-sized spot results in high energy density and gives rise to ablation phenomena not seen during laser processing with larger beam diameters. Use of acousto-optic deflectors (AODs) enabled us to test different laser beam steering approaches in terms of choosing the position for each laser pulse independently of the previous pulses. Random addressing of desired positions across a microstructure proved to be the most efficient method compared to various scanning approaches. Assigning a random order to the spatial sequence of laser pulses resulted in the fastest microstructuring process and featured lowest residual heating of the substrate.

  16. Application of Support Vector Machine to Ship Steering

    Institute of Scientific and Technical Information of China (English)

    LUO Wei-lin; ZOU Zao-jian; LI Tie-shan

    2009-01-01

    System identification is an effective way for modeling ship manoeuvring motion and ship manoeuvrability prediction. Support vector machine is proposed to identify the manoeuvring indices in four different response models of ship steering motion, including the first order linear, the first order nonlinear, the second order linear and the second order nonlinear models. Predictions of manoeuvres including trained samples by using the identified parameters are compared with the results of free-running model tests. It is discussed that the different four categories are consistent with each other both analytically and numerically. The generalization of the identified model is verified by predicting different untrained manoeuvres. The simulations and comparisons demonstrate the validity of the proposed method.

  17. Acoustic Prism for Continuous Beam Steering Based on Piezoelectric Metamaterial

    CERN Document Server

    Xu, Jiawen

    2016-01-01

    This paper investigates an acoustic prism for continuous acoustic beam steering by a simple frequency sweep. This idea takes advantages of acoustic wave velocity shifting in metamaterials in the vicinity of local resonance. We apply this concept into the piezoelectric metamaterial consisting of host medium and piezoelectric LC shunt. Theoretical modeling and FEM simulations are carried out. It is shown that the phase velocity of acoustic wave changes dramatically in the vicinity of local resonance. The directions of acoustic wave can be adjusted continuously between 2 to 16 degrees by a simple sweep of the excitation frequency. Such an electro-mechanical coupling system has a feature of adjusting local resonance without altering the mechanical part of the system.

  18. Sugar transport across lactose permease probed by steered molecular dynamics

    DEFF Research Database (Denmark)

    Jensen, Morten Østergaard; Yin, Ying; Tajkhorshid, Emad

    2007-01-01

    Escherichia coli lactose permease (LacY) transports sugar across the inner membrane of the bacterium using the proton motive force to accumulate sugar in the cytosol. We have probed lactose conduction across LacY using steered molecular dynamics, permitting us to follow molecular and energetic......, forcing it to interact with channel lining residues. Lactose forms a multitude of direct sugar-channel hydrogen bonds, predominantly with residues of the flexible N-domain, which is known to contribute a major part of LacY's affinity for lactose. In the periplasmic half-channel lactose predominantly...... interacts with hydrophobic channel lining residues, whereas in the cytoplasmic half-channel key protein-substrate interactions are mediated by ionic residues. A major energy barrier against transport is found within a tight segment of the periplasmic half-channel where sugar hydration is minimal and protein-sugar...

  19. A Novel Microwave Beam Steering Technique Using Plasma

    Science.gov (United States)

    Linardakis, Peter; Borg, Gerard G.; Harris, Jeffrey H.; Martin, Noel M.

    2002-10-01

    At frequencies above the plasma frequency, electromagnetic waves propagate through plasma with a wavelength longer than the free space wavelength. As a result, a plasma with a centrally peaked density profile can deflect rather than focus electromagnetic waves. We present a plasma device designed specifically to deflect a microwave beam as an alternative to conventional beam deflectors based on antenna arrays. A 22^rc deflection of Ka band microwave has been achieved using a laboratory plasma, with no detrimental effect on the beamwidth or side-lode level and structure. The use of a simple WKB model shows agreement and that the deflection can be increased with appropriate design. Results indicate the potential for increases in dynamic range, in power handling (for example from a gyrotron) and for the reduction of insertion losses over current beam steering systems. A ``plasma lens'' demonstrator device has also been designed to test practical performance aspects such as phase noise and to test optimization parameters.

  20. Lightweight computational steering of very large scale molecular dynamics simulations

    Energy Technology Data Exchange (ETDEWEB)

    Beazley, D.M. [Univ. of Utah, Salt Lake City, UT (United States). Dept. of Computer Science; Lomdahl, P.S. [Los Alamos National Lab., NM (United States)

    1996-09-01

    We present a computational steering approach for controlling, analyzing, and visualizing very large scale molecular dynamics simulations involving tens to hundreds of millions of atoms. Our approach relies on extensible scripting languages and an easy to use tool for building extensions and modules. The system is extremely easy to modify, works with existing C code, is memory efficient, and can be used from inexpensive workstations and networks. We demonstrate how we have used this system to manipulate data from production MD simulations involving as many as 104 million atoms running on the CM-5 and Cray T3D. We also show how this approach can be used to build systems that integrate common scripting languages (including Tcl/Tk, Perl, and Python), simulation code, user extensions, and commercial data analysis packages.

  1. Beam steering and impedance matching of plasmonic horn nanoantennas

    CERN Document Server

    Afridi, Adeel

    2016-01-01

    In this paper, we study a plasmonic horn nanoantenna on a metal-backed substrate. The horn nanoantenna structure consists of a two-wire transmission line (TWTL) flared at the end. We analyze the effect of the substrate thickness on the nanoantenna's radiation pattern, and demonstrate beam steering in a broad range of elevation angles. Furthermore, we analyze the effect of the ground plane on the impedance matching between the antenna and the TWTL, and observe that the ground plane increases the back reflection into the waveguide. To reduce the reflection, we develop a transmission line model to design an impedance matching section which leads to 99.75% power transmission to the nanoantenna.

  2. Redox environment effect on redox sensitive elements in surface sediments of the Changjiang Estuary hypoxia zone

    Institute of Scientific and Technical Information of China (English)

    Shumei XU; Shikui ZHAI; Aibin ZHANG; Huaijing ZHANG; Haijian LU

    2008-01-01

    The grain size and element (including redox sensitive elements and terrigenous elements) concentration of surface sediments from the Changjiang Estuary hypoxia zone and its adjacent sea area were measured in this research.Based on the obtained data,the hypoxic environment's influence on the distribution of elements in surface sediments was further studied.We believe that the "redox environment effect" greatly influences the distribution of the RSE,which reveals the "patchy enrichment pattern" offshore in the hypoxia zone,while the distribution of the terrigenous elements which shows the "stripped enrichment pattern" near shore is mainly affected by "granularity effects".Due to the existence of the hypoxia zone of the Changjiang Estuary,the distribution of the RSE such as Mo,Cd and V in the study area exhibits the characteristics of "redox environment effects".

  3. All-versus-nothing proof of Einstein-Podolsky-Rosen steering.

    Science.gov (United States)

    Chen, Jing-Ling; Ye, Xiang-Jun; Wu, Chunfeng; Su, Hong-Yi; Cabello, Adán; Kwek, L C; Oh, C H

    2013-01-01

    Einstein-Podolsky-Rosen steering is a form of quantum nonlocality intermediate between entanglement and Bell nonlocality. Although Schrödinger already mooted the idea in 1935, steering still defies a complete understanding. In analogy to "all-versus-nothing" proofs of Bell nonlocality, here we present a proof of steering without inequalities rendering the detection of correlations leading to a violation of steering inequalities unnecessary. We show that, given any two-qubit entangled state, the existence of certain projective measurement by Alice so that Bob's normalized conditional states can be regarded as two different pure states provides a criterion for Alice-to-Bob steerability. A steering inequality equivalent to the all-versus-nothing proof is also obtained. Our result clearly demonstrates that there exist many quantum states which do not violate any previously known steering inequality but are indeed steerable. Our method offers advantages over the existing methods for experimentally testing steerability, and sheds new light on the asymmetric steering problem.

  4. Test of Einstein-Podolsky-Rosen steering based on the all-versus-nothing proof.

    Science.gov (United States)

    Wu, Chunfeng; Chen, Jing-Ling; Ye, Xiang-Jun; Su, Hong-Yi; Deng, Dong-Ling; Wang, Zhenghan; Oh, C H

    2014-03-06

    In comparison with entanglement and Bell nonlocality, Einstein-Podolsky-Rosen steering is a newly emerged research topic and in its incipient stage. Although Einstein-Podolsky-Rosen steering has been explored via violations of steering inequalities both theoretically and experimentally, the known inequalities in the literatures are far from well-developed. As a result, it is not yet possible to observe Einstein-Podolsky-Rosen steering for some steerable mixed states. Recently, a simple approach was presented to identify Einstein-Podolsky-Rosen steering based on all-versus-nothing argument, offering a strong condition to witness the steerability of a family of two-qubit (pure or mixed) entangled states. In this work, we show that the all-versus-nothing proof of Einstein-Podolsky-Rosen steering can be tested by measuring the projective probabilities. Through the bound of probabilities imposed by local-hidden-state model, the proposed test shows that steering can be detected by the all-versus-nothing argument experimentally even in the presence of imprecision and errors. Our test can be implemented in many physical systems and we discuss the possible realizations of our scheme with non-Abelian anyons and trapped ions.

  5. Dynamic steering beams for efficient force measurement in optical manipulation

    Institute of Scientific and Technical Information of China (English)

    Xiaocong Yuan; Yuquan Zhang; Rui Cao; Xing Zhao; Jing Bu; Siwei Zhu

    2011-01-01

    @@ An efficient and inexpensive method that uses a glass plate mounted onto a motorized rotating stage as a beam-steering device for the generation of dynamic optical traps is reported.Force analysis reveals that there are drag and trapping forces imposed on the bead in the opposite directions, respectively, in a viscous medium.The trapped bead will be rotated following the beam's motion before it reaches the critical escape velocity when the drag force is equal to the optical trapping force.The equilibrium condition facilitates the experimental measurement of the drag force with potential extensions to the determination of the viscosity of the medium or the refractive index of the bead.The proposed technique can easily be integrated into conventional optical microscopic systems with minimum modifications.%An efficient and inexpensive method that uses a glass plate mounted onto a motorized rotating stage as a beam-steering device for the generation of dynamic optical traps is reported. Force analysis reveals that there are drag and trapping forces imposed on the bead in the opposite directions, respectively, in a viscous medium. The trapped bead will be rotated following the beam's motion before it reaches the critical escape velocity when the drag force is equal to the optical trapping force. The equilibrium condition facilitates the experimental measurement of the drag force with potential extensions to the determination of the viscosity of the medium or the refractive index of the bead. The proposed technique can easily be integrated into conventional optical microscopic systems with minimum modifications.

  6. DSP-based electric power assisted steering using BLDC motor

    Indian Academy of Sciences (India)

    R Murugan; S Nandakumar; M S Mohiyadeen

    2008-10-01

    This paper introduces a design and implementation of electrically assisted power steering (EAS) using BLDC motor for a vehicle. The control architecture consists of two layers of control, namely the vehicle speed associated control and the torque assist control. In the higher level of control architecture, the vehicle speed controller works as an assistance level controller for the steering effort. In the lower level, the torque controller gives the effort level control. This has been realized by torque sensor and vehicle sensor interfaced in the DSP. For implementing in the system, a DSP-based BLDC motor controller with three-phase inverter module is specially designed using Hall-effect sensor feedback and a single dc-link current sensor. This work is implemented in a Light Commercial Vehicle having a recirculating ball type gear. This is for the first time (EAS) being implemented for this type of vehicle any where in the world. Generally, EAS having clutch to disconnect the motor in high speed or abnormal conditions from the gear box. In this implementation the motor is directly coupled to gearbox without clutch and all abnormalities are handled by the processor. This is implemented without modifying the vehicle supply system like changing the existing alternator or rating of the battery and using the existing sensors. The design is such a way that the feel of the driver assistance can be varied easily at any time. The performance of the control system is experimentally verified and it is tested in one of the Light Commercial Vehicle (LCV).

  7. Multiple redox states of multiheme cytochromes may enable bacterial response to changing redox environments

    Science.gov (United States)

    Arbour, T.; Wrighton, K. C.; Mullin, S. W.; Castelle, C.; Luef, B.; Gilbert, B.; Banfield, J. F.

    2013-12-01

    Multiheme c-type cytochromes (MHCs) are key components in electron-transport pathways that enable some microorganisms to transfer electron byproducts of metabolism to a variety of minerals. As a response to changes in mineral redox potential, microbial communities may shift their membership, or individual organisms may adjust protein expression. Alternatively, the ability to respond may be conferred by the innate characteristics of certain electron-transport-chain components. Here, we used potentiostat-controlled microbial fuel cells (MFCs) to measure the timescale of response to imposed changes in redox conditions, thus placing constraints on the importance of these different mechanisms. In the experiments, a solid electrode acts as an electron-accepting mineral whose redox potential can be precisely controlled. We inoculated duplicate MFCs with a sediment/groundwater mixture from an aquifer at Rifle, Colorado, supplied acetate as an electron donor, and obtained stable, mixed-species biofilms dominated by Geobacter and a novel Geobacter-related family. We poised the anode at potentials spanning the range of natural Fe(III)-reduction, then performed cyclic voltammetry (CV) to characterize the overall biofilm redox signature. The apparent biofilm midpoint potential shifted directly with anode set potential when the latter was changed within the range from about -250 to -50 mV vs. SHE. Following a jump in set potential by 200 mV, the CV-midpoint shift by ~100 mV over a timescale of ~30 minutes to a few hours, depending on the direction of the potential change. The extracellular electron transfer molecules, whose overall CV signature is very similar to those of purified MHCs, appear to span a broad redox range (~200 mV), supporting the hypothesis that MHCs confer substantial redox flexibility. This flexibility may be a principle reason for the abundance of MHCs expressed by microorganisms capable of extracellular electron transfer to minerals.

  8. Feedlot performance of Brahman x Angus versus Angus steers during cold weather.

    Science.gov (United States)

    Boyles, S L; Riley, J G

    1991-07-01

    Ten Angus and 10 Brahman x Angus F1 steers were used in a 184-d trial to compare feedlot performance during cold weather (-9 to 26 degrees C). Both groups of steers were exposed to the same environment for the same amount of time. All steers were fed for the same number of days regardless of frame score to avoid frame score x environment interactions. Brahman x Angus steers were 30.7 kg heavier (P less than .05) than Angus steers at the start of the trial. Differences in age (Brahman x Angus 40 d younger) for the two breed groups did not affect final live weight or carcass weight. Brahman x Angus steers consumed .2% less feed (P less than .05) as a percentage of BW than Angus steers; however, there was no difference in overall feed efficiency. Angus steers had a higher yield grade, more fat at the 12th rib (P less than .05), and graded 90% Choice; only 10% of the Brahman x Angus were graded Choice. Brahman x Angus steers were taller at the hip (P less than .05) and longer from first rib to aitch bone (P less than .05) and from thoracic vertebrae (T12/T13) to point of hock (P less than .05). Hide thickness determined at the neck, belly, and rump was found to be similar (7.7 mm) between the two groups. Sample hair weight and diameter did not differ between groups. Fiber, fat, protein, and DM digestibility coefficients were similar between groups but Brahman x Angus feces had a higher DM content.(ABSTRACT TRUNCATED AT 250 WORDS)

  9. Feedlot performance, carcass traits, and palatability traits of Hereford and Hereford x Brahman steers.

    Science.gov (United States)

    Sherbeck, J A; Tatum, J D; Field, T G; Morgan, J B; Smith, G C

    1995-12-01

    Short-yearling steer of known genotypes-straightbred Hereford (100H, n = 80) 75% Hereford x 25% Brahman (75H:25B, n = 80), and 50% Hereford x 50% Brahman (50H:50B, n = 80) were sampled serially at four time-on-feed endpoints (84, 98, 112, 126 d) to compare feedlot performance and carcass and palatability traits of Hereford and Hereford x Brahman steers. After slaughter, USDA yield grade and quality grade factors were recorded, and a portion of the longissimus muscle was removed from the left side of each carcass and fabricated into four 2.54-cm steaks for palatability analyses. Paired steaks from each carcass were aged (6 and 18 d after death), and sensory panel and shear force evaluations were performed. At a constant live weight, 100H steers had higher ADG and produced less mature carcasses with smaller longissimus muscle areas and higher marbling scores than did 75H:25B and 50H:50B steers. The 50H:50B steers had the highest (P Brahman breeding increased. EXtending the postmortem aging period from 6 to 18 d improved shear force values by 20% and panel tenderness ratings by approximately 14%. Beef from steers of the three breeds responded similarly to aging. When Certified Hereford Beef (CHB) specifications were applied, steaks from 100H steers and 75H:25B steers had similar shear force values, suggesting that beef from quarter-blood Brahman crossbred steers could be included in the CHB Program without detrimental effects on product tenderness.

  10. Throughput-Based Traffic Steering in LTE-Advanced HetNet Deployments

    DEFF Research Database (Denmark)

    Gimenez, Lucas Chavarria; Kovacs, Istvan Z.; Wigard, Jeroen;

    2015-01-01

    The objective of this paper is to propose traffic steering solutions that aim at optimizing the end-user throughput. Two different implementations of an active mode throughput-based traffic steering algorithm for Heterogeneous Networks (HetNet) are introduced. One that always forces handover...... slightly lower traffic steering gains at a considerably lower cost in terms of number of handovers. The gain in terms of increased average session throughput for the second option equals 32% at low-load, 18% at medium-load, and 7% at high-load conditions. The gain in the fifth percentile user session...

  11. A new generation of IC based beam steering devices for free-space optical communication

    Science.gov (United States)

    Bedi, Vijit

    Free Space Optical (FSO) communication has tremendously advanced within the last decade to meet the ever increasing demand for higher communication bandwidth. Advancement in laser technology since its invention in the 1960's [1] attracted them to be the dominant source in FSO communication modules. The future of FSO systems lay in implementing semiconductor lasers due to their small size, power efficiency and mass fabrication abilities. In the near future, these systems are very likely to be used in space and ground based applications and revolutionary beam steering technologies will be required for distant communications in free-space. The highly directional characteristic inherent to a laser beam challenges and calls for new beam pointing and steering technologies for such type of communication. In this dissertation, research is done on a novel FSO communication device based on semiconductor lasers for high bandwidth communication. The "Fly eye transceiver" is an extremely wide steering bandwidth, completely non-mechanical FSO laser communication device primarily designed to replace traditional mechanical beam steering optical systems. This non-mechanical FSO device possesses a full spherical steering range and a very high tracking bandwidth. Inspired by the evolutionary model of a fly's eye, the full spherical steering range is assured by electronically controlled switching of its sub-eyes. Non mechanical technologies used in the past for beam steering such as acousto-optic Bragg cells, liquid crystal arrays or piezoelectric elements offer the wide steering bandwidth and fast response time, but are limited in their angular steering range. Mechanical gimbals offer a much greater steering range but face a much slower response time or steering bandwidth problem and often require intelligent adaptive controls with bulky driver amplifiers to feed their actuators. As a solution to feed both the fast and full spherical steering, the Fly-eye transceiver is studied as

  12. Three-Dimensional Acoustic Source Mapping with Different Beamforming Steering Vector Formulations

    Directory of Open Access Journals (Sweden)

    Ennes Sarradj

    2012-01-01

    are governed by the steering vectors, four different steering vector formulations from the literature are examined, and their theoretical background is discussed. It is found that none of the formulations provide both the correct location and source strength. As a practical example the CLEAN-SC deconvolution methodology is applied to simulated data for a three-source scenario. It is shown that the different steering vector formulations are not equally well suited for three-dimensional application. The two preferred formulations enable the correct estimation of the source location at the cost of a negligible error in the estimated source strength.

  13. The Influence Of The Ship's Steering Machine Over Yaw And Roll Motions

    Directory of Open Access Journals (Sweden)

    Viorel NICOLAU

    2003-12-01

    Full Text Available The steering machine is a nonlinear system, with two important limitations: the maximum rudder angle and rudder rate. Therefore, the commands from yaw and rudder-roll control systems are modified and the expected effect is not always the optimum one. It is important to know the influence of the steering machine, trying to avoid the limitations or to include them into the control law. The goal of this paper is to analyze the steering machine limitations and their influence over yaw and roll motions of the ship. Also, some expert rules are generated, which can be used to implement more efficient control laws.

  14. Organic non-aqueous cation-based redox flow batteries

    Energy Technology Data Exchange (ETDEWEB)

    Jansen, Andrew N.; Vaughey, John T.; Chen, Zonghai; Zhang, Lu; Brushett, Fikile R.

    2016-03-29

    The present invention provides a non-aqueous redox flow battery comprising a negative electrode immersed in a non-aqueous liquid negative electrolyte, a positive electrode immersed in a non-aqueous liquid positive electrolyte, and a cation-permeable separator (e.g., a porous membrane, film, sheet, or panel) between the negative electrolyte from the positive electrolyte. During charging and discharging, the electrolytes are circulated over their respective electrodes. The electrolytes each comprise an electrolyte salt (e.g., a lithium or sodium salt), a transition-metal free redox reactant, and optionally an electrochemically stable organic solvent. Each redox reactant is selected from an organic compound comprising a conjugated unsaturated moiety, a boron cluster compound, and a combination thereof. The organic redox reactant of the positive electrolyte is selected to have a higher redox potential than the redox reactant of the negative electrolyte.

  15. Characterization of redox conditions in groundwater contaminant plumes

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Bjerg, Poul Løgstrup; Banwarth, Steven A.;

    2000-01-01

    Evaluation of redox conditions in groundwater pollution plumes is often a prerequisite for understanding the behaviour of the pollutants in the plume and for selecting remediation approaches. Measuring of redox conditions in pollution plumes is, however, a fairly recent issue and yet relative few...... cases have been reported. No standardised or generally accepted approach exists. Slow electrode kinetics and the common lack of internal equilibrium of redox processes in pollution plumes make, with a few exceptions, direct electrochemical measurement and rigorous interpretation of redox potentials...... dubious, if not erroneous. Several other approaches have been used in addressing redox conditions in pollution plumes: redox-sensitive compounds in groundwater samples, hydrogen concentrations in groundwater, concentrations of volatile fatty acids in groundwater, sediment characteristics and microbial...

  16. Nanostructured Electrocatalysts for All-Vanadium Redox Flow Batteries.

    Science.gov (United States)

    Park, Minjoon; Ryu, Jaechan; Cho, Jaephil

    2015-10-01

    Vanadium redox reactions have been considered as a key factor affecting the energy efficiency of the all-vanadium redox flow batteries (VRFBs). This redox reaction determines the reaction kinetics of whole cells. However, poor kinetic reversibility and catalytic activity towards the V(2+)/V(3+) and VO(2+)/VO2(+) redox couples on the commonly used carbon substrate limit broader applications of VRFBs. Consequently, modified carbon substrates have been extensively investigated to improve vanadium redox reactions. In this Focus Review, recent progress on metal- and carbon-based nanomaterials as an electrocatalyst for VRFBs is discussed in detail, without the intention to provide a comprehensive review on the whole components of the system. Instead, the focus is mainly placed on the redox chemistry of vanadium ions at a surface of various metals, different dimensional carbons, nitrogen-doped carbon nanostructures, and metal-carbon composites.

  17. 氧化锡粒子/石墨烯纳米复合材料真空热还原制备及其在近红外胰腺癌热疗中的应用∗%Redox Approaches Derived Tin (Ⅳ)Oxide Nanoparticles/Graphene Nanocompo-sites as the Near-infrared Absorber for Human Prostate Cancer Cells Destruction

    Institute of Scientific and Technical Information of China (English)

    程金生; 朱文娟; 万维宏; 张志顺

    2015-01-01

    利用真空热还原法制备得到氧化锡粒子/石墨烯纳米复合材料(SnO2/GR),该过程中,石墨烯氧化物原料既是氧化锡粒子的有效载体来源,也是新型的活泼氧给体,可同步将零价锡氧化为正四价锡,石墨烯氧化物原料则被还原为石墨烯。利用透射电镜(TEM)、扫描电镜(SEM)、X 射线衍射(XRD)和傅里叶变换红外光谱等分别对氧化锡粒子/石墨烯纳米复合材料的形貌和尺寸、结构进行了表征。利用该新型材料在近红外(NIR)激光照射下的强光热转化性能,使相比健康细胞更易受到温度影响的胰腺肿瘤细胞内部产生过高热(Hyperthermia),从而诱导胰腺肿瘤细胞热损伤及细胞凋亡。实验结果表明,在1064 nm 近红外激光照射下,对照组胰腺肿瘤细胞仍保持较高活性,而实验组的胰腺肿瘤细胞活力则大幅降至5.03%,充分显示了氧化锡粒子/石墨烯纳米复合材料在胰腺肿瘤热疗领域的潜力。%Tin (Ⅳ)oxide nanoparticles/graphene (SnO2/GR)nanocomposites were prepared via vacuum ther-mo treatment of Tin (0)and graphene oxide (GO).A redox reaction would occur readily in this process,in which the novel oxygen donor:GO could act as the oxidizing agent to oxidize Tin (0)to Tin (Ⅳ),meanwhile,the graphene pre-cursor:GO would be simultaneously reduced to graphene by Tin (0)readily.The resulted composites were characte-rized by Fourier transform infrared spectrometry,scanning electron microscopy,and X-ray diffraction spectroscopy etc..The novel SnO2/GR nanocomposites could combine both advantages of inorganic metal nanoparticles and gra-phene for near infrared spectroscopy (NIR)light absorption to generate heat,which fosters SnO2/GR a special candi-date for photothermal ablation therapy (PTA)with NIR.Further investigations showed that the SnO2/GR nanocom-posites with NIR features could provide viable option for enhancing the thermal deposition (as it could significantly

  18. Redox homeostasis: The Golden Mean of healthy living

    Directory of Open Access Journals (Sweden)

    Fulvio Ursini

    2016-08-01

    Full Text Available The notion that electrophiles serve as messengers in cell signaling is now widely accepted. Nonetheless, major issues restrain acceptance of redox homeostasis and redox signaling as components of maintenance of a normal physiological steady state. The first is that redox signaling requires sudden switching on of oxidant production and bypassing of antioxidant mechanisms rather than a continuous process that, like other signaling mechanisms, can be smoothly turned up or down. The second is the misperception that reactions in redox signaling involve “reactive oxygen species” rather than reaction of specific electrophiles with specific protein thiolates. The third is that hormesis provides protection against oxidants by increasing cellular defense or repair mechanisms rather than by specifically addressing the offset of redox homeostasis. Instead, we propose that both oxidant and antioxidant signaling are main features of redox homeostasis. As the redox shift is rapidly reversed by feedback reactions, homeostasis is maintained by continuous signaling for production and elimination of electrophiles and nucleophiles. Redox homeostasis, which is the maintenance of nucleophilic tone, accounts for a healthy physiological steady state. Electrophiles and nucleophiles are not intrinsically harmful or protective, and redox homeostasis is an essential feature of both the response to challenges and subsequent feedback. While the balance between oxidants and nucleophiles is preserved in redox homeostasis, oxidative stress provokes the establishment of a new radically altered redox steady state. The popular belief that scavenging free radicals by antioxidants has a beneficial effect is wishful thinking. We propose, instead, that continuous feedback preserves nucleophilic tone and that this is supported by redox active nutritional phytochemicals. These nonessential compounds, by activating Nrf2, mimic the effect of endogenously produced electrophiles

  19. Redox homeostasis: The Golden Mean of healthy living

    OpenAIRE

    Fulvio Ursini; Matilde Maiorino; Henry Jay Forman

    2016-01-01

    The notion that electrophiles serve as messengers in cell signaling is now widely accepted. Nonetheless, major issues restrain acceptance of redox homeostasis and redox signaling as components of maintenance of a normal physiological steady state. The first is that redox signaling requires sudden switching on of oxidant production and bypassing of antioxidant mechanisms rather than a continuous process that, like other signaling mechanisms, can be smoothly turned up or down. The second is the...

  20. Electron transfer and interfacial behavior of redox proteins

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    This paper reviews the recent progress in the electron transfer and interfacial behavior of redox proteins. Significant achievements in the relevant fields are summarized including the direct electron transfer between proteins and electrodes, the thermodynamic and kinetic properties, catalytic activities and activity regulation of the redox proteins. It has been demonstrated that the electrochemical technique is an effective tool for protein studies, especially for probing into the electron transfer and interfacial behavior of redox proteins.

  1. Factors Controlling Redox Speciation of Plutonium and Neptunium in Extraction Separation Processes

    Energy Technology Data Exchange (ETDEWEB)

    Paulenova, Alena [Principal Investigator; Vandegrift, III, George F. [Collaborator

    2013-09-24

    The objective of the project was to examine the factors controlling redox speciation of plutonium and neptunium in UREX+ extraction in terms of redox potentials, redox mechanism, kinetics and thermodynamics. Researchers employed redox-speciation extractions schemes in parallel to the spectroscopic experiments. The resulting distribution of redox species w studied uring spectroscopic, electrochemical, and spectro-electrochemical methods. This work reulted in collection of data on redox stability and distribution of redox couples in the nitric acid/nitrate electrolyte and the development of redox buffers to stabilize the desired oxidation state of separated radionuclides. The effects of temperature and concentrations on the redox behavior of neptunium were evaluated.

  2. Chiral Redox-Active Isosceles Triangles.

    Science.gov (United States)

    Nalluri, Siva Krishna Mohan; Liu, Zhichang; Wu, Yilei; Hermann, Keith R; Samanta, Avik; Kim, Dong Jun; Krzyaniak, Matthew D; Wasielewski, Michael R; Stoddart, J Fraser

    2016-05-11

    Designing small-molecule organic redox-active materials, with potential applications in energy storage, has received considerable interest of late. Herein, we report on the synthesis, characterization, and application of two rigid chiral triangles, each of which consist of non-identical pyromellitic diimide (PMDI) and naphthalene diimide (NDI)-based redox-active units. (1)H and (13)C NMR spectroscopic investigations in solution confirm the lower symmetry (C2 point group) associated with these two isosceles triangles. Single-crystal X-ray diffraction analyses reveal their rigid triangular prism-like geometries. Unlike previously investigated equilateral triangle containing three identical NDI subunits, both isosceles triangles do not choose to form one-dimensional supramolecular nanotubes by dint of [C-H···O] interaction-driven columnar stacking. The rigid isosceles triangle, composed of one NDI and two PMDI subunits, forms-in the presence of N,N-dimethylformamide-two different types of intermolecular NDI-NDI and NDI-PMDI π-π stacked dimers with opposite helicities in the solid state. Cyclic voltammetry reveals that both isosceles triangles can accept reversibly up to six electrons. Continuous-wave electron paramagnetic resonance and electron-nuclear double-resonance spectroscopic investigations, supported by density functional theory calculations, on the single-electron reduced radical anions of the isosceles triangles confirm the selective sharing of unpaired electrons among adjacent redox-active NDI subunit(s) within both molecules. The isosceles triangles have been employed as electrode-active materials in organic rechargeable lithium-ion batteries. The evaluation of the structure-performance relationships of this series of diimide-based triangles reveals that the increase in the number of NDI subunits, replacing PMDI ones, within the molecules improves the electrochemical cell performance of the batteries.

  3. Dimensional behavior of Ni-YSZ composites during redox cycling

    DEFF Research Database (Denmark)

    Pihlatie, Mikko; Kaiser, Andreas; Larsen, Peter Halvor;

    2009-01-01

    The dimensional behavior of Ni-yttria-stabilized zirconia (YSZ) cermets during redox cycling was tested in dilatometry within the temperature range 600-1000 degrees C. The effect Of humidity oil redox stability was investigated at intermediate and low temperatures. We show that both the sintering...... of nickel depending on temperature of the initial reduction and the operating conditions, and the temperature of reoxidation are very important for the size of the dimensional change. Cumulative redox strain (CRS) is shown to be correlated with temperature. Measured maximum CRS after three redox cycles...

  4. Electronic Tongue Containing Redox and Conductivity Sensors

    Science.gov (United States)

    Buehler, Martin

    2007-01-01

    The Electronic Tongue (E-tongue 2) is an assembly of sensors for measuring concentrations of metal ions and possibly other contaminants in water. Potential uses for electronic tongues include monitoring the chemical quality of water in a variety of natural, industrial, and laboratory settings, and detecting micro-organisms indirectly by measuring microbially influenced corrosion. The device includes a heater, a temperature sensor, an oxidation/reduction (redox) sensor pair, an electrical sensor, an array of eight galvanic cells, and eight ion-specific electrodes.

  5. Redox shuttles for lithium ion batteries

    Science.gov (United States)

    Weng, Wei; Zhang, Zhengcheng; Amine, Khalil

    2014-11-04

    Compounds may have general Formula IVA or IVB. ##STR00001## where, R.sup.8, R.sup.9, R.sup.10, and R.sup.11 are each independently selected from H, F, Cl, Br, CN, NO.sub.2, alkyl, haloalkyl, and alkoxy groups; X and Y are each independently O, S, N, or P; and Z' is a linkage between X and Y. Such compounds may be used as redox shuttles in electrolytes for use in electrochemical cells, batteries and electronic devices.

  6. Redox Equilibria in SO2 Oxidation Catalysts

    DEFF Research Database (Denmark)

    Rasmussen, Søren Birk; Eriksen, Kim Michael; Boghosian, Soghomon

    1999-01-01

    been carried out regarding the complex and compound formation of V(V) and the formation of V(IV) and V(III) compounds with low solubility causing catalyst deactivation. However, the redox chemistry of vanadium and the complex formation of V(IV) is much less investigated and further information...... on these subjects in pyrosulfate melts is needed to obtain a deeper understanding of the reaction mechanism. The present paper describes our efforts so far to study the V(IV) chemistry using especially spectroscopic and electrochemical methods....

  7. Proterozoic ocean redox and biogeochemical stasis

    OpenAIRE

    Reinhard, Christopher T.; Noah J. Planavsky; Robbins, Leslie J.; Partin, Camille A.; Gill, Benjamin C.; Lalonde, Stefan V; Bekker, Andrey; Konhauser, Kurt O.; Lyons, Timothy W.

    2013-01-01

    The partial pressure of oxygen in Earth’s atmosphere has increased dramatically through time, and this increase is thought to have occurred in two rapid steps at both ends of the Proterozoic Eon (∼2.5–0.543 Ga). However, the trajectory and mechanisms of Earth’s oxygenation are still poorly constrained, and little is known regarding attendant changes in ocean ventilation and seafloor redox. We have a particularly poor understanding of ocean chemistry during the mid-Proterozoic (∼1.8–0.8 Ga). G...

  8. Sedimentary cobalt concentrations track marine redox evolution

    Science.gov (United States)

    Swanner, Elizabeth; Planavsky, Noah; Lalonde, Stefan; Robbins, Jamie; Bekker, Andrey; Rouxel, Olivier; Konhauser, Kurt O.; Mojzsis, Stephen J.

    2013-04-01

    Oxygen production by photosynthesis drove the redox evolution of the atmosphere and ocean. Primary productivity by oxygenic photosynthesizers in the modern surface ocean is limited by trace nutrients such as iron, but previous studies have also observed high Co uptake associated with natural cyanobacterial populations. Constraining the size and variation of the oceanic reservoir of Co through time will help to understand the regulation of primary productivity and hence oxygenation through time. In this study, Co concentrations from iron formations (IF), shales and marine pyrites deposited over nearly 4 billion years of Earth's history are utilized to reconstruct secular changes in the mechanisms of Co removal from the oceanic reservoir. The Co reservoir prior to ~2 Ga was dominated by hydrothermal inputs and Fe(III)oxyhydroxides were likely involved in the removal of Co from the water column. Fe(II) oxidation in the water column resulted in the deposition of IF in the Archean and Paleoproterozoic, and the Co inventory of IF records a large oceanic reservoir of Co during this time. Lower Co concentrations in sediments during the Middle Proterozoic signify a decrease in the oceanic reservoir due to the expansion euxinic environments, corresponding to the results of previous studies. A transition to an oxidized deep ocean in the Phanerozoic is evidenced by correlation between Co and manganese (Mn) concentrations in hydrothermal and exhalative deposits, and in marine pyrites. This relationship between Co and Mn, signifying deposition of Co in association with Mn(IV)oxides, does not occur in the Precambrian. Mn(II) oxidation occurs at higher redox potentials than that required for Fe(II) oxidation, and the extent of Mn redox cycling prior to full ventilation of the oceans at the end of the Neoproterozoic was likely limited to spatially restricted oxic surface waters. In this regard, Co is another valuable redox proxy for tracking the growth and decline in oxygenated

  9. Fe-V redox flow batteries

    Science.gov (United States)

    Li, Liyu; Kim, Soowhan; Yang, Zhenguo; Wang, Wei; Zhang, Jianlu; Chen, Baowei; Nie, Zimin; Xia, Guanguang

    2014-07-08

    A redox flow battery having a supporting solution that includes Cl.sup.- anions is characterized by an anolyte having V.sup.2+ and V.sup.3+ in the supporting solution, a catholyte having Fe.sup.2+ and Fe.sup.3+ in the supporting solution, and a membrane separating the anolyte and the catholyte. The anolyte and catholyte can have V cations and Fe cations, respectively, or the anolyte and catholyte can each contain both V and Fe cations in a mixture. Furthermore, the supporting solution can contain a mixture of SO.sub.4.sup.2- and Cl.sup.- anions.

  10. Rebalancing electrolytes in redox flow battery systems

    Science.gov (United States)

    Chang, On Kok; Pham, Ai Quoc

    2014-12-23

    Embodiments of redox flow battery rebalancing systems include a system for reacting an unbalanced flow battery electrolyte with a rebalance electrolyte in a first reaction cell. In some embodiments, the rebalance electrolyte may contain ferrous iron (Fe.sup.2+) which may be oxidized to ferric iron (Fe.sup.3+) in the first reaction cell. The reducing ability of the rebalance reactant may be restored in a second rebalance cell that is configured to reduce the ferric iron in the rebalance electrolyte back into ferrous iron through a reaction with metallic iron.

  11. Anticancer clinical utility of the apurinic/apyrimidinic endonuclease/redox factor-1 (APE/Ref-1).

    Science.gov (United States)

    Zhang, Ying; Wang, Jian

    2010-03-01

    Apurinic/apyrimidinic endonuclease/redox factor-1 (APE/Ref-1), as a type of multifunctional protein, plays an essential role in the base excision repair (BER) pathway, which is responsible for the repair of DNA caused by oxidative and alkylation damage. As importantly, APE/Ref-1 also functions as a redox factor maintaining transcription factors in an active reduced state. APE/Ref-1 stimulates the DNA-binding activity of numerous transcription factors that are involved in cancer promotion and progression, such as AP-1 (Fos/Jun), NF-kappaB, HIF-1alpha, p53, and others. Based on the structures and functions of APE1/Ref-1, we will provide an overview of its activities and explore the budding clinical use of this protein as a target in cancer treatment, and propose that APE/Ref-1 has a great potential for application in clinical research.

  12. Carboxylate shifts steer interquinone electron transfer in photosynthesis.

    Science.gov (United States)

    Chernev, Petko; Zaharieva, Ivelina; Dau, Holger; Haumann, Michael

    2011-02-18

    Understanding the mechanisms of electron transfer (ET) in photosynthetic reaction centers (RCs) may inspire novel catalysts for sunlight-driven fuel production. The electron exit pathway of type II RCs comprises two quinone molecules working in series and in between a non-heme iron atom with a carboxyl ligand (bicarbonate in photosystem II (PSII), glutamate in bacterial RCs). For decades, the functional role of the iron has remained enigmatic. We tracked the iron site using microsecond-resolution x-ray absorption spectroscopy after laser-flash excitation of PSII. After formation of the reduced primary quinone, Q(A)(-), the x-ray spectral changes revealed a transition (t½ ≈ 150 μs) from a bidentate to a monodentate coordination of the bicarbonate at the Fe(II) (carboxylate shift), which reverted concomitantly with the slower ET to the secondary quinone Q(B). A redox change of the iron during the ET was excluded. Density-functional theory calculations corroborated the carboxylate shift both in PSII and bacterial RCs and disclosed underlying changes in electronic configuration. We propose that the iron-carboxyl complex facilitates the first interquinone ET by optimizing charge distribution and hydrogen bonding within the Q(A)FeQ(B) triad for high yield Q(B) reduction. Formation of a specific priming intermediate by nuclear rearrangements, setting the stage for subsequent ET, may be a common motif in reactions of biological redox cofactors.

  13. Quantum Steering Inequality with Tolerance for Measurement-Setting Errors: Experimentally Feasible Signature of Unbounded Violation

    Science.gov (United States)

    Rutkowski, Adam; Buraczewski, Adam; Horodecki, Paweł; Stobińska, Magdalena

    2017-01-01

    Quantum steering is a relatively simple test for proving that the values of quantum-mechanical measurement outcomes come into being only in the act of measurement. By exploiting quantum correlations, Alice can influence—steer—Bob's physical system in a way that is impossible in classical mechanics, as shown by the violation of steering inequalities. Demonstrating this and similar quantum effects for systems of increasing size, approaching even the classical limit, is a long-standing challenging problem. Here, we prove an experimentally feasible unbounded violation of a steering inequality. We derive its universal form where tolerance for measurement-setting errors is explicitly built in by means of the Deutsch-Maassen-Uffink entropic uncertainty relation. Then, generalizing the mutual unbiasedness, we apply the inequality to the multisinglet and multiparticle bipartite Bell state. However, the method is general and opens the possibility of employing multiparticle bipartite steering for randomness certification and development of quantum technologies, e.g., random access codes.

  14. National Status and Trends: Bioeffects Program - St. Thomas East End Reserves (STEER) Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The purpose of this effort was to characterize the extent and magnitude of chemical contamination in the St. Thomas East End Reserves or STEER, as part of a larger...

  15. Practicability study on the suitability of artificial, neural networks for the approximation of unknown steering torques

    Science.gov (United States)

    Van Ende, K. T. R.; Schaare, D.; Kaste, J.; Küçükay, F.; Henze, R.; Kallmeyer, F. K.

    2016-10-01

    For steer-by-wire systems, the steering feedback must be generated artificially due to the system characteristics. Classical control concepts require operating-point driven optimisations as well as increased calibration efforts in order to adequately simulate the steering torque in all driving states. Artificial neural networks (ANNs) are an innovative control concept; they are capable of learning arbitrary non-linear correlations without complex knowledge of physical dependencies. The present study investigates the suitability of neural networks for approximating unknown steering torques. To ensure robust processing of arbitrary data, network training with a sufficient volume of training data is required, that represents the relation between the input and target values in a wide range. The data were recorded in the course of various test drives. In this research, a variety of network topologies were trained, analysed and evaluated. Though the fundamental suitability of ANNs for the present control task was demonstrated.

  16. Violation of Continuous-Variable Einstein-Podolsky-Rosen Steering with Discrete Measurements

    Science.gov (United States)

    Schneeloch, James; Dixon, P. Ben; Howland, Gregory A.; Broadbent, Curtis J.; Howell, John C.

    2013-03-01

    In this Letter, we derive an entropic Einstein-Podolsky-Rosen (EPR) steering inequality for continuous-variable systems using only experimentally measured discrete probability distributions and details of the measurement apparatus. We use this inequality to witness EPR steering between the positions and momenta of photon pairs generated in spontaneous parametric down-conversion. We examine the asymmetry between parties in this inequality, and show that this asymmetry can be used to reduce the technical requirements of experimental setups intended to demonstrate the EPR paradox. Furthermore, we develop a more stringent steering inequality that is symmetric between parties, and use it to show that the down-converted photon pairs also exhibit symmetric EPR steering.

  17. Fault Risk Assessment of Underwater Vehicle Steering System Based on Virtual Prototyping and Monte Carlo Simulation

    Directory of Open Access Journals (Sweden)

    He Deyu

    2016-09-01

    Full Text Available Assessing the risks of steering system faults in underwater vehicles is a human-machine-environment (HME systematic safety field that studies faults in the steering system itself, the driver’s human reliability (HR and various environmental conditions. This paper proposed a fault risk assessment method for an underwater vehicle steering system based on virtual prototyping and Monte Carlo simulation. A virtual steering system prototype was established and validated to rectify a lack of historic fault data. Fault injection and simulation were conducted to acquire fault simulation data. A Monte Carlo simulation was adopted that integrated randomness due to the human operator and environment. Randomness and uncertainty of the human, machine and environment were integrated in the method to obtain a probabilistic risk indicator. To verify the proposed method, a case of stuck rudder fault (SRF risk assessment was studied. This method may provide a novel solution for fault risk assessment of a vehicle or other general HME system.

  18. Modelling driver behaviour in the case of failures in a steer-by-wire system

    NARCIS (Netherlands)

    Hogema, J.; Wewerinke, P.H.

    2010-01-01

    In dit artikel wordt een bestuurdersmodel gepresenteerd dat weergeeft hoe een bestuurder reagerrtt op systeemfouten in een steer-by-wire tuursysteem. Calibratie en validatie vond plaats aan de hand van data van een rijsimulator experiment

  19. EPR-Steering measure for two-mode continuous variable states

    CERN Document Server

    Kogias, Ioannis

    2014-01-01

    Steering is a manifestation of quantum correlations that embodies the Einstein-Podolsky-Rosen (EPR) paradox. While there have been recent attempts to quantify steering, continuous variable systems remained elusive. We introduce a steering measure for two-mode continuous variable systems that is valid for arbitrary states. The measure is based on the violation of an optimized variance test for the EPR paradox, and admits a computable and experimentally friendly lower bound only depending on the second moments of the state, which reduces to a recently proposed quantifier of steerability by Gaussian measurements. We further show that Gaussian states are extremal with respect to our measure, minimizing it among all continuous variable states with fixed second moments. As a byproduct of our analysis, we generalize and relate well-known EPR-steering criteria. Finally an operational interpretation is provided, as the proposed measure is shown to quantify the optimal guaranteed key rate in semi-device independent qua...

  20. Characteristics of Hand Transmitted Vibration through Steering Wheel of Tractor during Ploughing Field

    Directory of Open Access Journals (Sweden)

    Md Zakaullah Zaka

    2015-02-01

    Full Text Available The paper presents the transmission of vibrations through the steering wheel of the tractor during the ploughing field. The measurements of vibration were carried out on the tractor randomly chosen. An investigation was conducted to determine the transmission of vibration from the steering wheel of the tractor to the wrists and upper arms of the operator under actual field conditions during ploughing field. The vibrations transmitted through the steering wheel of the tractor to the hand of the operator was measured and the frequency spectra for the chosen working conditions were obtained. The maximum transmissibility of vibration were observed in the first two frequency interval (in Hz i.e. 1-20 and 20-40. The vibration, which is transmitted from the steering wheel of the tractor to the wrists, arms and shoulders causes discomfort to the operator and results in early fatigue.

  1. Temporal steering and security of quantum key distribution with mutually unbiased bases against individual attacks

    Science.gov (United States)

    Bartkiewicz, Karol; Černoch, Antonín; Lemr, Karel; Miranowicz, Adam; Nori, Franco

    2016-06-01

    Temporal steering, which is a temporal analog of Einstein-Podolsky-Rosen steering, refers to temporal quantum correlations between the initial and final state of a quantum system. Our analysis of temporal steering inequalities in relation to the average quantum bit error rates reveals the interplay between temporal steering and quantum cloning, which guarantees the security of quantum key distribution based on mutually unbiased bases against individual attacks. The key distributions analyzed here include the Bennett-Brassard 1984 protocol and the six-state 1998 protocol by Bruss. Moreover, we define a temporal steerable weight, which enables us to identify a kind of monogamy of temporal correlation that is essential to quantum cryptography and useful for analyzing various scenarios of quantum causality.

  2. Fatty acid composition differences between adipose depot sites in dairy and beef steer breeds.

    Science.gov (United States)

    Liu, T; Lei, Z M; Wu, J P; Brown, M A

    2015-03-01

    The objective of the study was to compare fatty acid composition of longissimus dorsi (LD) and kidney fat (KF) in Holstein steers (HS), Simmental steers (SS) and Chinese LongDong Yellow Cattle steers (CLD). All steers received the same nutrition and management but in different locations. Cattle were harvested at approximately 550 kg and fatty acid composition of longissimus dorsi and kidney fat was analyzed in samples taken after 3 days of aging. There was evidence (P fatty acids were greater in LD than KF for all breeds (P fatty acids (PUFA), monounsaturated fatty acids (MUFA), and a greater ratio of n6:n3 PUFAs compared to the KF in each breed (P fatty acid percentages generally differed between longissimus dorsi fat and kidney fat. Further, there was some indication that some of these differences between fatty acid deposition sites were not consistent across breed group.

  3. Molecular chaperones and proteostasis regulation during redox imbalance

    Directory of Open Access Journals (Sweden)

    Katerina Niforou

    2014-01-01

    Full Text Available Free radicals originate from both exogenous environmental sources and as by-products of the respiratory chain and cellular oxygen metabolism. Sustained accumulation of free radicals, beyond a physiological level, induces oxidative stress that is harmful for the cellular homeodynamics as it promotes the oxidative damage and stochastic modification of all cellular biomolecules including proteins. In relation to proteome stability and maintenance, the increased concentration of oxidants disrupts the functionality of cellular protein machines resulting eventually in proteotoxic stress and the deregulation of the proteostasis (homeostasis of the proteome network (PN. PN curates the proteome in the various cellular compartments and the extracellular milieu by modulating protein synthesis and protein machines assembly, protein recycling and stress responses, as well as refolding or degradation of damaged proteins. Molecular chaperones are key players of the PN since they facilitate folding of nascent polypeptides, as well as holding, folding, and/or degradation of unfolded, misfolded, or non-native proteins. Therefore, the expression and the activity of the molecular chaperones are tightly regulated at both the transcriptional and post-translational level at organismal states of increased oxidative and, consequently, proteotoxic stress, including ageing and various age-related diseases (e.g. degenerative diseases and cancer. In the current review we present a synopsis of the various classes of intra- and extracellular chaperones, the effects of oxidants on cellular homeodynamics and diseases and the redox regulation of chaperones.

  4. Dynamic Steering for Improved Sensor Autonomy and Catalogue Maintenance

    Science.gov (United States)

    Hobson, T.; Gordon, N.; Clarkson, I.; Rutten, M.; Bessell, T.

    A number of international agencies endeavour to maintain catalogues of the man-made resident space objects (RSOs) currently orbiting the Earth. Such catalogues are primarily created to anticipate and avoid destructive collisions involving important space assets such as manned missions and active satellites. An agencys ability to achieve this objective is dependent on the accuracy, reliability and timeliness of the information used to update its catalogue. A primary means for gathering this information is by regularly making direct observations of the tens-of-thousands of currently detectable RSOs via networks of space surveillance sensors. But operational constraints sometimes prevent accurate and timely reacquisition of all known RSOs, which can cause them to become lost to the tracking system. Furthermore, when comprehensive acquisition of new objects does not occur, these objects, in addition to the lost RSOs, result in uncorrelated detections when next observed. Due to the rising number of space-missions and the introduction of newer, more capable space-sensors, the number of uncorrelated targets is at an all-time high. The process of differentiating uncorrelated detections caused by once-acquired now-lost RSOs from newly detected RSOs is a difficult and often labour intensive task. Current methods for overcoming this challenge focus on advancements in orbit propagation and object characterisation to improve prediction accuracy and target identification. In this paper, we describe a complementary approach that incorporates increased awareness of error and failed observations into the RSO tracking solution. Our methodology employs a technique called dynamic steering to improve the autonomy and capability of a space surveillance networks steerable sensors. By co-situating each sensor with a low-cost high-performance computer, the steerable sensor can quickly and intelligently decide how to steer itself. The sensor-system uses a dedicated parallel

  5. The enzyme-amplified amperometric DNA sensor using an electrodeposited polymer redox mediator

    Institute of Scientific and Technical Information of China (English)

    ZHANG LanYong; WAN Ying; ZHANG Jiong; LI Di; WANG LiHua; SONG ShiPing; FAN ChunHai

    2009-01-01

    A highly sensitive method for the detection of a breast cancer-associated BRCA-1 gene is reported. The detection is based on a classical sandwich-type assay using horseradish peroxidase (HRP) as a cata-lytic label and electrodeposited Os2+/3+ conducting polymer (PAA-PVi-Os) as a redox mediator. Target DNA could be detected by the HRP-catalyzed reduction of H2O2, leading to a limit of detection as low as 10 fM.

  6. Effect of automobile operating condition on the subjective equivalence of steering wheel vibration and sound

    OpenAIRE

    2007-01-01

    For the manufacturers of automobiles, automobile components and fuels, subjective equivalence relationships between vibration and sound can be used as a reference against which to plot the results from simulations or tests of specific operational conditions. The research described here was performed to define curves of subjective equivalence between steering wheel rotational vibration and sound using stimuli from different automobile operating conditions. The steering wheel acceleration stimu...

  7. Optical steering of thermally generated microbubbles in a liquid for targeted metallic nanoparticle delivery

    Science.gov (United States)

    Krishnappa, Arjun; Abeywickrema, Ujitha; Banerjee, Partha

    2016-09-01

    A novel mathematical model is developed to investigate the behavior of thermally generated microbubbles in the presence of optical radiation to understand the mechanism of their steering. Forces acting on a bubble are studied in detail using a general force model. It has been proposed that these microbubbles with agglomerated metallic nanoparticles can be used for targeted drug delivery. The model can be extended to include the steering of bubbles with agglomerated silver or gold nanoparticles on their surface.

  8. Perspectives of Ethical Identity in Ng's Steer toward Rock and Jen's Mona in the Promised Land

    OpenAIRE

    Su,Hui

    2015-01-01

    In her article "Perspectives of Ethical Identity in Ng's Steer toward Rock and Jen's Mona in the Promised Land" Hui Su examines Fae Myenne Ng's and Gish Jen's novels. In the novels, the protagonists make different decisions: in Steer Toward Rock Jack after displacement in China adopts US-American identity and in Mona in the Promised Land Mona, a second generation Chinese American, selects Jewish identity. Owing to their different situations, the two protagonists reflect challenges of identity...

  9. Metal-binding and redox properties of substituted linear and cyclic ATCUN motifs.

    Science.gov (United States)

    Neupane, Kosh P; Aldous, Amanda R; Kritzer, Joshua A

    2014-10-01

    The amino-terminal copper and nickel binding (ATCUN) motif is a short peptide sequence found in human serum albumin and other proteins. Synthetic ATCUN-metal complexes have been used to oxidatively cleave proteins and DNA, cross-link proteins, and damage cancer cells. The ATCUN motif consists of a tripeptide that coordinates Cu(II) and Ni(II) ions in a square planar geometry, anchored by chelation sites at the N-terminal amine, histidine imidazole and two backbone amides. Many studies have shown that the histidine is required for tight binding and square planar geometry. Previously, we showed that macrocyclization of the ATCUN motif can lead to high-affinity binding with altered metal ion selectivity and enhanced Cu(II)/Cu(III) redox cycling (Inorg. Chem. 2013, 52, 2729-2735). In this work, we synthesize and characterize several linear and cyclic ATCUN variants to explore how substitutions at the histidine alter the metal-binding and catalytic properties. UV-visible spectroscopy, EPR spectroscopy and mass spectrometry indicate that cyclization can promote the formation of ATCUN-like complexes even in the absence of imidazole. We also report several novel ATCUN-like complexes and quantify their redox properties. These findings further demonstrate the effects of conformational constraints on short, metal-binding peptides, and also provide novel redox-active metallopeptides suitable for testing as catalysts for stereoselective or regioselective oxidation reactions.

  10. Therapeutic Targeting of Redox Signaling in Myofibroblast Differentiation and Age-Related Fibrotic Disease

    Directory of Open Access Journals (Sweden)

    Natalie Sampson

    2012-01-01

    Full Text Available Myofibroblast activation plays a central role during normal wound healing. Whereas insufficient myofibroblast activation impairs wound healing, excessive myofibroblast activation promotes fibrosis in diverse tissues (including benign prostatic hyperplasia, BPH leading to organ dysfunction and also promotes a stromal response that supports tumor progression. The incidence of impaired wound healing, tissue fibrosis, BPH, and certain cancers strongly increases with age. This paper summarizes findings from in vitro fibroblast-to-myofibroblast differentiation systems that serve as cellular models to study fibrogenesis of diverse tissues. Supported by substantial in vivo data, a large body of evidence indicates that myofibroblast differentiation induced by the profibrotic cytokine transforming growth factor beta is driven by a prooxidant shift in redox homeostasis due to elevated production of NADPH oxidase 4 (NOX4-derived hydrogen peroxide and supported by concomitant decreases in nitric oxide/cGMP signaling and reactive oxygen species (ROS scavenging enzymes. Fibroblast-to-myofibroblast differentiation can be inhibited and reversed by restoring redox homeostasis using antioxidants or NOX4 inactivation as well as enhancing nitric oxide/cGMP signaling via activation of soluble guanylyl cyclases or inhibition of phosphodiesterases. Current evidence indicates the therapeutic potential of targeting the prooxidant shift in redox homeostasis for the treatment of age-related diseases associated with myofibroblast dysregulation.

  11. Redox state alteration modulates astrocyte glucuronidation.

    Science.gov (United States)

    Heurtaux, T; Benani, A; Bianchi, A; Moindrot, A; Gradinaru, D; Magdalou, J; Netter, P; Minn, A

    2004-10-01

    We have investigated the effects of mild oxidative conditions on drug-metabolizing enzyme activity in rat cultured astrocytes. These experimental conditions promoting an oxidative environment were obtained by short exposure to a low concentration of menadione (5 microM) for a short duration (15 min). This resulted in the rapid and transient production of reactive oxygen species (+130%), associated with a decrease in GSH cellular content (-24%), and an increase in total protein oxidation (+26%), but promoted neither PGE(2) nor NO production. This treatment induced a rapid and persistent decrease in astrocyte glucuronidation activities, which was totally prevented by N-acetyl-l-cysteine. These oxidative conditions also affected the specific UGT1A6 activity measured in transfected V79-1A6 cells. Finally, the subsequent recovery of astrocyte glucuronidation activity may result from upregulation of UGT1A6 expression (+62%) as shown by RT-PCR and gene reporter assay. These results show that the catalytic properties and expression of cerebral UGT1A6 are highly sensitive to the redox environment. The protective effect of N-acetyl-l-cysteine suggests both a direct action of reactive oxygen species on the protein and a more delayed action on the transcriptional regulation of UGT1A6. These results suggest that cerebral metabolism can be altered by physiological or pathological redox modifications.

  12. Redox driven conductance changes for resistive memory

    Energy Technology Data Exchange (ETDEWEB)

    Shoute, Lian C.T.; McCreery, Richard L. [National Institute for Nanotechnology, Edmonton, Alberta (Canada); University of Alberta, Department of Chemistry, Edmonton, Alberta (Canada); Pekas, Nikola [National Institute for Nanotechnology, Edmonton, Alberta (Canada); Wu, Yiliang [Xerox Research Centre of Canada, Mississauga, Ontario (Canada)

    2011-03-15

    The relationship between bias-induced redox reactions and resistance switching is considered for memory devices containing TiO{sub 2} or a conducting polymer in ''molecular heterojunctions'' consisting of thin (2-25 nm) films of covalently bonded molecules, polymers, and oxides. Raman spectroscopy was used to monitor changes in the oxidation state of polythiophene in Au/P3HT/SiO{sub 2}/Au devices, and it was possible to directly determine the formation and stability of the conducting polaron state of P3HT by applied bias pulses [P3HT = poly(3-hexyl thiophene)]. Polaron formation was strongly dependent on junction composition, particularly on the interfaces between the polymer, oxide, and electrodes. In all cases, trace water was required for polaron formation, leading to the proposal that water reduction acts as a redox counter-reaction to polymer oxidation. Polaron stability was longest for the case of a direct contact between Au and SiO{sub 2}, implying that catalytic water reduction at the Au surface generated hydroxide ions which stabilized the cationic polaron. The spectroscopic information about the dependence of polaron stability on device composition will be useful for designing and monitoring resistive switching memory based on conducting polymers, with or without TiO{sub 2} present. (orig.)

  13. Redox driven conductance changes for resistive memory

    Science.gov (United States)

    Shoute, Lian C. T.; Pekas, Nikola; Wu, Yiliang; McCreery, Richard L.

    2011-03-01

    The relationship between bias-induced redox reactions and resistance switching is considered for memory devices containing TiO2 or a conducting polymer in "molecular heterojunctions" consisting of thin (2-25 nm) films of covalently bonded molecules, polymers, and oxides. Raman spectroscopy was used to monitor changes in the oxidation state of polythiophene in Au/P3HT/SiO2/Au devices, and it was possible to directly determine the formation and stability of the conducting polaron state of P3HT by applied bias pulses [P3HT = poly(3-hexyl thiophene)]. Polaron formation was strongly dependent on junction composition, particularly on the interfaces between the polymer, oxide, and electrodes. In all cases, trace water was required for polaron formation, leading to the proposal that water reduction acts as a redox counter-reaction to polymer oxidation. Polaron stability was longest for the case of a direct contact between Au and SiO2, implying that catalytic water reduction at the Au surface generated hydroxide ions which stabilized the cationic polaron. The spectroscopic information about the dependence of polaron stability on device composition will be useful for designing and monitoring resistive switching memory based on conducting polymers, with or without TiO2 present.

  14. Redox regulation of mammalian sperm capacitation

    Directory of Open Access Journals (Sweden)

    Cristian O′Flaherty

    2015-01-01

    Full Text Available Capacitation is a series of morphological and metabolic changes necessary for the spermatozoon to achieve fertilizing ability. One of the earlier happenings during mammalian sperm capacitation is the production of reactive oxygen species (ROS that will trigger and regulate a series of events including protein phosphorylation, in a time-dependent fashion. The identity of the sperm oxidase responsible for the production of ROS involved in capacitation is still elusive, and several candidates are discussed in this review. Interestingly, ROS-induced ROS formation has been described during human sperm capacitation. Redox signaling during capacitation is associated with changes in thiol groups of proteins located on the plasma membrane and subcellular compartments of the spermatozoon. Both, oxidation of thiols forming disulfide bridges and the increase on thiol content are necessary to regulate different sperm proteins associated with capacitation. Reducing equivalents such as NADH and NADPH are necessary to support capacitation in many species including humans. Lactate dehydrogenase, glucose-6-phospohate dehydrogenase, and isocitrate dehydrogenase are responsible in supplying NAD (P H for sperm capacitation. Peroxiredoxins (PRDXs are newly described enzymes with antioxidant properties that can protect mammalian spermatozoa; however, they are also candidates for assuring the regulation of redox signaling required for sperm capacitation. The dysregulation of PRDXs and of enzymes needed for their reactivation such as thioredoxin/thioredoxin reductase system and glutathione-S-transferases impairs sperm motility, capacitation, and promotes DNA damage in spermatozoa leading to male infertility.

  15. Redox iodine and nitric acid absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Stoker, D.J.; Rohrmann, C.A.

    1955-08-02

    A desirable radio-iodine emission goal for all HAPO has recently been set at one curie per day maximum. At the same time it was suggested that a more relaxed limit of ten curries per week with no more than three in any one day, would probably be satisfactory. To assure the achievement of these goal figures in the separations plants it was deemed necessary to either cool'' the irradiated material a greater length of time than is presently done before processing, or provide more efficient, iodine retention facilities. Increased power levels, higher production rates, and an increase in the awareness of radio-iodine emissions, have all coupled together to make present facilities generally inadequate when processing material aged less than about 100 days. Several alternate methods of providing additional iodine retention facilities for Redox were preliminarily scoped and presented for consideration. The purpose of this report is to present a scope design for improving iodine emission control at Redox.

  16. Interactive steering of supercomputing simulation for aerodynamic noise radiated from square cylinder; Supercomputer wo mochiita steering system ni yoru kakuchu kara hoshasareru kurikion no suchi kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Yokono, Y. [Toshiba Corp., Tokyo (Japan); Fujita, H. [Tokyo Inst. of Technology, Tokyo (Japan). Precision Engineering Lab.

    1995-03-25

    This paper describes extensive computer simulation for aerodynamic noise radiated from a square cylinder using an interactive steering supercomputing simulation system. The unsteady incompressible three-dimensional Navier-Stokes equations are solved by the finite volume method using a steering system which can visualize the numerical process during calculation and alter the numerical parameter. Using the fluctuating surface pressure of the square cylinder, the farfield sound pressure is calculated based on Lighthill-Curle`s equation. The results are compared with those of low noise wind tunnel experiments, and good agreement is observed for the peak spectrum frequency of the sound pressure level. 14 refs., 10 figs.

  17. Exploration quantum steering, nonlocality and entanglement of two-qubit X-state in structured reservoirs

    Science.gov (United States)

    Sun, Wen-Yang; Wang, Dong; Shi, Jia-Dong; Ye, Liu

    2017-01-01

    In this work, there are two parties, Alice on Earth and Bob on the satellite, which initially share an entangled state, and some open problems, which emerge during quantum steering that Alice remotely steers Bob, are investigated. Our analytical results indicate that all entangled pure states and maximally entangled evolution states (EESs) are steerable, and not every entangled evolution state is steerable and some steerable states are only locally correlated. Besides, quantum steering from Alice to Bob experiences a “sudden death” with increasing decoherence strength. However, shortly after that, quantum steering experiences a recovery with the increase of decoherence strength in bit flip (BF) and phase flip (PF) channels. Interestingly, while they initially share an entangled pure state, all EESs are steerable and obey Bell nonlocality in PF and phase damping channels. In BF channels, all steerable states can violate Bell-CHSH inequality, but some EESs are unable to be employed to realize steering. However, when they initially share an entangled mixed state, the outcome is different from that of the pure state. Furthermore, the steerability of entangled mixed states is weaker than that of entangled pure states. Thereby, decoherence can induce the degradation of quantum steering, and the steerability of state is associated with the interaction between quantum systems and reservoirs. PMID:28145467

  18. Robust H2/H∞ Control for the Electrohydraulic Steering System of a Four-Wheel Vehicle

    Directory of Open Access Journals (Sweden)

    Min Ye

    2014-01-01

    Full Text Available To shorten the steer diameter and to improve the maneuverability flexibility of a construction vehicle, four wheels’ steering system is presented. This steering system consists of mechanical-electrical-hydraulic assemblies. Its diagram and principle are depicted in detail. Then the mathematical models are derived step by step, including the whole vehicle model and the hydraulic route model. Considering the nonlinear and time-varying uncertainty of the steering system, robust H2/H∞ controller is put forward to guarantee both the system performance and the robust stability. The H∞ norm of the sensitive function from the parameter perturbation of the hydraulic system to the yaw velocity of the vehicle is taken as the evaluating index of the robustness and the H2 norm of the transfer function from the external disturbance to the steering angle of the wheel as the index of linear quadratic Gaussian. The experimental results showed that the proposed scheme was superior to classical PID controller and can guarantee both the control performance and the robustness of the steering system.

  19. Need for airbag and seatbelt to reduce orbital injuries from steering wheel knob.

    Science.gov (United States)

    Hwang, Kun; Kim, Joo Ho

    2014-11-01

    The aims of this study are to report a blowout fracture of the orbital floor and medial wall caused by being struck by a steering wheel knob of an automobile and to discuss the use of airbags and seatbelts as a preventive measure for orbital injuries. A 58-year-old man was struck in the left eye by a steering wheel. His car hit a telephone pole, and he had a frontal collision injury. In this frontal impact, his left eye was hit by a Brodie knob attached to the steering wheel. At the time of injury, the speed of the car was about 65 km/h. He was not wearing a seatbelt, and the airbag had not deployed. Swelling and ecchymosis were observed at the left periorbital area, and he had diplopia on a left-side gaze. A CT revealed fractures in the medial and inferior wall of the left orbit. Entrapped soft tissues were reduced, and the medial wall and floor were reconstructed with a resorbable sheet. His diplopia disappeared 12 days after surgery. To prevent the injury from the steering wheel knob, an airbag should be installed in any vehicle, which has a steering wheel knob. Legislation mandating the use of airbags as well as seatbelts in vehicles with attached steering wheel knobs should be made.

  20. Adaptive Sliding Mode Control Method Based on Nonlinear Integral Sliding Surface for Agricultural Vehicle Steering Control

    Directory of Open Access Journals (Sweden)

    Taochang Li

    2014-01-01

    Full Text Available Automatic steering control is the key factor and essential condition in the realization of the automatic navigation control of agricultural vehicles. In order to get satisfactory steering control performance, an adaptive sliding mode control method based on a nonlinear integral sliding surface is proposed in this paper for agricultural vehicle steering control. First, the vehicle steering system is modeled as a second-order mathematic model; the system uncertainties and unmodeled dynamics as well as the external disturbances are regarded as the equivalent disturbances satisfying a certain boundary. Second, a transient process of the desired system response is constructed in each navigation control period. Based on the transient process, a nonlinear integral sliding surface is designed. Then the corresponding sliding mode control law is proposed to guarantee the fast response characteristics with no overshoot in the closed-loop steering control system. Meanwhile, the switching gain of sliding mode control is adaptively adjusted to alleviate the control input chattering by using the fuzzy control method. Finally, the effectiveness and the superiority of the proposed method are verified by a series of simulation and actual steering control experiments.

  1. Image reconstruction using projections from a few views by discrete steering combined with DART

    Science.gov (United States)

    Kwon, Junghyun; Song, Samuel M.; Kauke, Brian; Boyd, Douglas P.

    2012-03-01

    In this paper, we propose an algebraic reconstruction technique (ART) based discrete tomography method to reconstruct an image accurately using projections from a few views. We specifically consider the problem of reconstructing an image of bottles filled with various types of liquids from X-ray projections. By exploiting the fact that bottles are usually filled with homogeneous material, we show that it is possible to obtain accurate reconstruction with only a few projections by an ART based algorithm. In order to deal with various types of liquids in our problem, we first introduce our discrete steering method which is a generalization of the binary steering approach for our proposed multi-valued discrete reconstruction. The main idea of the steering approach is to use slowly varying thresholds instead of fixed thresholds. We further improve reconstruction accuracy by reducing the number of variables in ART by combining our discrete steering with the discrete ART (DART) that fixes the values of interior pixels of segmented regions considered as reliable. By simulation studies, we show that our proposed discrete steering combined with DART yields superior reconstruction than both discrete steering only and DART only cases. The resulting reconstructions are quite accurate even with projections using only four views.

  2. 3-D ultrasound-guided robotic needle steering in biological tissue.

    Science.gov (United States)

    Adebar, Troy K; Fletcher, Ashley E; Okamura, Allison M

    2014-12-01

    Robotic needle steering systems have the potential to greatly improve medical interventions, but they require new methods for medical image guidance. Three-dimensional (3-D) ultrasound is a widely available, low-cost imaging modality that may be used to provide real-time feedback to needle steering robots. Unfortunately, the poor visibility of steerable needles in standard grayscale ultrasound makes automatic segmentation of the needles impractical. A new imaging approach is proposed, in which high-frequency vibration of a steerable needle makes it visible in ultrasound Doppler images. Experiments demonstrate that segmentation from this Doppler data is accurate to within 1-2 mm. An image-guided control algorithm that incorporates the segmentation data as feedback is also described. In experimental tests in ex vivo bovine liver tissue, a robotic needle steering system implementing this control scheme was able to consistently steer a needle tip to a simulated target with an average error of 1.57 mm. Implementation of 3-D ultrasound-guided needle steering in biological tissue represents a significant step toward the clinical application of robotic needle steering.

  3. Exploration quantum steering, nonlocality and entanglement of two-qubit X-state in structured reservoirs

    Science.gov (United States)

    Sun, Wen-Yang; Wang, Dong; Shi, Jia-Dong; Ye, Liu

    2017-02-01

    In this work, there are two parties, Alice on Earth and Bob on the satellite, which initially share an entangled state, and some open problems, which emerge during quantum steering that Alice remotely steers Bob, are investigated. Our analytical results indicate that all entangled pure states and maximally entangled evolution states (EESs) are steerable, and not every entangled evolution state is steerable and some steerable states are only locally correlated. Besides, quantum steering from Alice to Bob experiences a “sudden death” with increasing decoherence strength. However, shortly after that, quantum steering experiences a recovery with the increase of decoherence strength in bit flip (BF) and phase flip (PF) channels. Interestingly, while they initially share an entangled pure state, all EESs are steerable and obey Bell nonlocality in PF and phase damping channels. In BF channels, all steerable states can violate Bell-CHSH inequality, but some EESs are unable to be employed to realize steering. However, when they initially share an entangled mixed state, the outcome is different from that of the pure state. Furthermore, the steerability of entangled mixed states is weaker than that of entangled pure states. Thereby, decoherence can induce the degradation of quantum steering, and the steerability of state is associated with the interaction between quantum systems and reservoirs.

  4. Fenton Redox Chemistry: Arsenite Oxidation by Metallic Surfaces

    NARCIS (Netherlands)

    Borges Freitas, S.C.; Van Halem, D.; Badruzzaman, A.B.M.; Van der Meer, W.G.J.

    2014-01-01

    Pre-oxidation of As(III) is necessary in arsenic removal processes in order to increase its efficiency. Therefore, the Fenton Redox Chemistry is defined by catalytic activation of H2O2 and currently common used for its redox oxidative properties. In this study the effect of H2O2 production catalysed

  5. Elucidation of the Mechanism of Redox Grafting of Diazotated Anthraquinone

    DEFF Research Database (Denmark)

    Chernyy, Sergey; Bousquet, Antoine; Torbensen, Kristian;

    2012-01-01

    Redox grafting of aryldiazonium salts containing redox units may be used to form exceptionally thick covalently attached conductingfilms, even in the micrometers range, in a controlled manner on glassy carbon and gold substrates. With the objective to investigate the mechanism of this process in ...

  6. Are bioassays useful tools to assess redox processes and biodegradation?

    DEFF Research Database (Denmark)

    Albrechtsen, Hans-Jørgen; Pedersen, Philip Grinder; Ludvigsen, L.

    2002-01-01

    sensitive hydrochemical or geochemical parameters, levels of hydrogen, and redox potential. However, all these approaches have to be evaluated against TEAP-bioassays as the most direct measure. We assessed successfully ongoing microbial-mediated redox processes by TEAP-bioassays in degradation studies...

  7. Redox regulation in malaria: current concepts and pharmacotherapeutic implications.

    Science.gov (United States)

    Goyal, M; Alam, A; Bandyopadhyay, U

    2012-01-01

    Malaria imposes a serious threat to human and becomes more prevalent due to the emergence of drug resistant parasite. Understanding of the underlying mechanism of drug resistance and identification of novel drug targets are key effective processes for the management of malaria. Malaria parasite is highly susceptible to oxidative stress but lives in a pro-oxidant rich environment containing oxygen and iron, which produce a large amount of reactive oxygen species. Management of oxidative stress in malaria parasite is tightly regulated through active redox and antioxidant defense systems. The elevation of oxidative stress as a result of inhibition of any component of this defense system leads to redox imbalance and ultimately parasite death. Therefore, redox system plays an indispensable role for the survival of parasite within the host. Identification of key molecules, which disrupt parasite redox balance by altering key redox reactions and promote oxidative stress in parasites, would be an effective approach to develop novel antimalarial drugs. During the last few decades, contributions by researchers around the globe provide even better understanding of redox biology of malaria parasite. Here, in this review, we are highlighting the knowledge gathered so far regarding the essential redox-active processes and their components in malaria parasite to overcome elevated oxidative insults. We have also given maximum efforts to enlist currently used redox-active antimalarials, their mode of action and pharmacotherapeutic implications.

  8. Development of the fast steering secondary mirror assembly of GMT

    Science.gov (United States)

    Lee, Sungho; Cho, Myung K.; Park, Chan; Han, Jeong-Yeol; Jeong, Ueejeong; Yoon, Yang-noh; Song, Je Heon; Park, Byeong-Gon; Dribusch, Christoph; Park, Won Hyun; Jun, Youra; Yang, Ho-Soon; Moon, Il-Kwon; Oh, Chang Jin; Kim, Ho-Sang; Lee, Kyoung-Don; Bernier, Robert; Alongi, Chris; Rakich, Andrew; Gardner, Paul; Dettmann, Lee; Rosenthal, Wylie

    2016-07-01

    The Giant Magellan Telescope (GMT) will be featured with two Gregorian secondary mirrors, an adaptive secondary mirror (ASM) and a fast-steering secondary mirror (FSM). The FSM has an effective diameter of 3.2 m and built as seven 1.1 m diameter circular segments, which are conjugated 1:1 to the seven 8.4m segments of the primary. Each FSM segment contains a tip-tilt capability for fine co-alignment of the telescope sub-apertures and fast guiding to attenuate telescope wind shake and mount control jitter. This tip-tilt capability thus enhances performance of the telescope in the seeing limited observation mode. As the first stage of the FSM development, Phase 0 study was conducted to develop a program plan detailing the design and manufacturing process for the seven FSM segments. The FSM development plan has been matured through an internal review by the GMTO-KASI team in May 2016 and fully assessed by an external review in June 2016. In this paper, we present the technical aspects of the FSM development plan.

  9. The ATLAS High Level Trigger Configuration and Steering

    CERN Document Server

    Stelzer, J; The ATLAS collaboration

    2010-01-01

    In March 2010 the four LHC experiments saw the first proton-proton collisions at 7 TeV. Still within the year a collision rate of nearly 10 MHz is expected. At ATLAS, events of potential interest for ATLAS physics are selected by a three level trigger system, with a final recording rate of about 200 Hz. The first level (L1) is implemented in customized hardware, the two levels of the high level trigger (HLT) are software triggers. Within the ATLAS physics program more than 500 trigger signatures are defined. The HLT tests each signature on each L1-accepted event, the test outcome is recorded for later analysis. The HLT-Steering is responsible for this. It foremost ensures the independent test of each signature, guarantying unbiased trigger decisions. Yet, to minimize data readout and execution time, cached detector data and once-calculated trigger objects are reused to form the decision. Some signature tests are performed only on a scaled-down fraction of candidate events, in order to reduce the output rate a...

  10. Obstacles and Drivers in Steering IBS towards Green and Sustainability

    Directory of Open Access Journals (Sweden)

    Seyed Meysam Khoshnava

    2014-10-01

    Full Text Available The aim of this study is investigating IBS potential solution for achieving its prospective in the area of green construction and sustainability. Malaysia has embarked on initiatives for sustainable development consistent with global concerns on the environment and sustaining the world resources for the future generations. The issues of sustainability and green construction have been duly highlighted in the Construction Industry Master Plan (2005-2015 as being of significant importance for the Malaysian construction industry. In this regard, industrialized construction has the unique characteristics to respond well to the sustainability challenge facing the construction industry. Industrialized construction assist adopters in term of cost and time certainty, attaining better construction quality and productivity, reducing risk related to occupational safety and health. But, despite all those capabilities most of the construction work in Malaysia is still applying conventional methods which are not often sustainable. Thus, this study tries to explore obstacles and drivers in steering IBS towards the agenda of green and sustainability.

  11. Process independent automated sizing methodology for current steering DAC

    Science.gov (United States)

    Vural, R. A.; Kahraman, N.; Erkmen, B.; Yildirim, T.

    2015-10-01

    This study introduces a process independent automated sizing methodology based on general regression neural network (GRNN) for current steering complementary metal-oxide semiconductor (CMOS) digital-to-analog converter (DAC) circuit. The aim is to utilise circuit structures designed with previous process technologies and to synthesise circuit structures for novel process technologies in contrast to other modelling researches that consider a particular process technology. The simulations were performed using ON SEMI 1.5 µm, ON SEMI 0.5 µm and TSMC 0.35 µm technology process parameters. Eventually, a high-dimensional database was developed consisting of transistor sizes of DAC designs and corresponded static specification errors obtained from simulation results. The key point is that the GRNN was trained with the data set including the simulation results of ON-SEMI 1.5 µm and 0.5 µm technology parameters and the test data were constituted with only the simulation results of TSMC 0.35 µm technology parameters that had not been applied to GRNN for training beforehand. The proposed methodology provides the channel lengths and widths of all transistors for a newer technology when the designer sets the numeric values of DAC static output specifications as Differential Non-linearity error, Integral Non-linearity error, monotonicity and gain error as the inputs of the network.

  12. Attosecond Steering of Electrons with Optimised Strong Field Waveforms

    CERN Document Server

    Haessler, S; Fan, G; Witting, T; Squibb, R; Chipperfield, L; Zaïr, A; Andriukaitis, G; Pugžlys, A; Tisch, J W G; Marangos, J P; Baltuška, A

    2013-01-01

    Quasi-free field driven electron trajectories are a key element of strong-field dynamics. Upon recollision with the parent ion, the energy transferred from the field to the electron may be released as attosecond duration XUV emission1,2 in the process of high harmonic generation (HHG). The conventional sinusoidal driver fields set limitations on the maximum value of this energy transfer, and it has been predicted that this limit can be significantly exceeded by an appropriately ramped-up cycle-shape3.Here, we present an experimental realization of such cycle-shaped waveforms and demonstrate control of the HHG process on the single-atom quantum level via attosecond steering of the electron trajectories. With our optimized optical cycles, we boost the field-ionization launching the electron trajectories, increase the subsequent field-to-electron energy transfer, and reduce the trajectory duration, to obtain greatly enhanced HHG efficiency as well as spectral extension compared to sinusoidal drivers. This applic...

  13. Harbour seals (Phoca vitulina) can steer by the stars.

    Science.gov (United States)

    Mauck, Björn; Gläser, Nele; Schlosser, Wolfhard; Dehnhardt, Guido

    2008-10-01

    Offshore orientation in marine mammals is still a mystery. For visual orientation during night-time foraging and travelling in the open seas, seals cannot rely on distant terrestrial landmarks, and thus might use celestial cues as repeatedly shown for nocturnally migrating birds. Although seals detect enough stars to probably allow for astronavigation, it was unclear whether they can orient by the night sky. The widely accepted cognitive mechanism for bird night-time orientation by celestial cues is a time-independent star compass with learned geometrical star configurations used to pinpoint north as the rotational centre of the starry sky while there is no conclusive evidence for a time-compensated star compass or true star navigation. Here, we present results for two harbour seals orienting in a custom made swimming planetarium. Both seals learned to highly accurately identify a lodestar out of a pseudo-randomly oriented, realistic projection of the northern hemisphere night sky. Providing the first evidence for star orientation capability in a marine mammal, our seals' outstanding directional precision would allow them to steer by following lodestars of learned star courses, a celestial orientation mechanism that has been known to be used by Polynesian navigators but has not been considered for animals yet.

  14. Modeling of miner track system during steering motion

    Institute of Scientific and Technical Information of China (English)

    刘少军; 韩庆珏

    2015-01-01

    Equipment for deep sea mining has risen from a position of virtual non-existence to a major industrial significance and in deep sea bed mining, the miner is the key equipment of the whole system that charges with the most complex and dangerous task. Evaluation of trafficability for tracked vehicles for deep sea mining is essential. Rare earth elements (REEs) are used in a wide range of modern applications. These applications are highly specific and substitutes are inferior or unknown. One possible source of the REE could be the poly-metallic nodule, at present explored in the tropical part of the Pacific Ocean. In developing miners of high performance, dynamic behaviour should be investigated under various traveling conditions. The mechanics of tracked vehicles is of continuing interest to organizations and agencies that specify design and operate tracked vehicles. Most works done are on the complete track vehicle system but in this work the research activity is aimed only at the track system with the basic aim of optimizing the track system design so that it can be manufactured by using the minimum resources. Equations and models are developed for the track system of a miner during steering motion. These equations and models could further be used for design optimization of the track system.

  15. Enteric listeriosis in grazing steers supplemented with spoiled silage.

    Science.gov (United States)

    García, Juan A; Micheloud, Juan F; Campero, Carlos M; Morrell, Eleonora L; Odriozola, Ernesto R; Moreira, Ana R

    2016-01-01

    An outbreak of enteric listeriosis in steers that were fed spoiled silage is reported. The outbreak started 2 days after ~200 animals in a single paddock were given a supplement of spoiled silage. Forty animals (20%) were affected, and 13 (6.5%) died over a period of 10 days. Affected animals were recumbent, depressed, and had diarrhea with mucus and fibrin. Gross and microscopic findings in 3 animals that were subjected to autopsy included excess peritoneal fluid, congestion and edema of abomasum, suppurative enteritis and colitis, and suppurative mesenteric lymphadenitis. Two strains of Listeria monocytogenes were isolated, one of serotype 1/2c from the gallbladder and one of serotype 1/2b from the spoiled silage. Listeria monocytogenes was detected in the mesenteric lymph nodes and intestinal wall of 1 animal by immunohistochemistry (IHC). Clinical history and signs, gross and microscopic findings, bacterial isolation, and IHC results confirmed a diagnosis of enteric listeriosis. The source of infection was likely the spoiled silage.

  16. Redox properties of extracellular polymeric substances (EPS) from electroactive bacteria

    Science.gov (United States)

    Li, Shan-Wei; Sheng, Guo-Ping; Cheng, Yuan-Yuan; Yu, Han-Qing

    2016-12-01

    Although the capacity for electroactive bacteria to convert environmental metallic minerals and organic pollutants is well known, the role of the redox properties of microbial extracellular polymeric substances (EPS) in this process is poorly understood. In this work, the redox properties of EPS from two widely present electroactive bacterial strains (Shewanella oneidensis and Pseudomonas putida) were explored. Electrochemical analysis demonstrates that the EPS extracted from the two strains exhibited redox properties. Spectroelectrochemical and protein electrophoresis analyses indicate that the extracted EPS from S. oneidensis and P. putida contained heme-binding proteins, which were identified as the possible redox components in the EPS. The results of heme-mediated behavior of EPS may provide an insight into the important roles of EPS in electroactive bacteria to maximize their redox capability for biogeochemical cycling, environmental bioremediation and wastewater treatment.

  17. Redox Impact on Starch Biosynthetic Enzymes in Arabidopsis thaliana

    DEFF Research Database (Denmark)

    Skryhan, Katsiaryna

    Summary The thesis provides new insight into the influence of the plant cell redox state on the transient starch metabolism in Arabidopsis thaliana with a focus on starch biosynthetic enzymes. Two main hypotheses forms the basis of this thesis: 1) photosynthesis and starch metabolism...... are coordinated by the redox state of the cell via post-translational modification of the starch metabolic enzymes containing redox active cysteine residues and these cysteine residues became cross-linked upon oxidation providing a conformational change leading to activity loss; 2) cysteine residues...... of chloroplast enzymes can play a role not only in enzyme activity and redox sensitivity but also in protein folding and stability upon oxidation. Several redox sensitive enzymes identified in this study can serve as potential targets to control the carbon flux to and from starch during the day and night...

  18. Measuring intracellular redox conditions using GFP-based sensors

    DEFF Research Database (Denmark)

    Björnberg, Olof; Ostergaard, Henrik; Winther, Jakob R

    2006-01-01

    Recent years have seen the development of methods for analyzing the redox conditions in specific compartments in living cells. These methods are based on genetically encoded sensors comprising variants of Green Fluorescent Protein in which vicinal cysteine residues have been introduced at solvent......-exposed positions. Several mutant forms have been identified in which formation of a disulfide bond between these cysteine residues results in changes of their fluorescence properties. The redox sensors have been characterized biochemically and found to behave differently, both spectroscopically and in terms...... of redox properties. As genetically encoded sensors they can be expressed in living cells and used for analysis of intracellular redox conditions; however, which parameters are measured depends on how the sensors interact with various cellular redox components. Results of both biochemical and cell...

  19. Simplified planar model of a car steering system with rack and pinion and McPherson suspension

    Science.gov (United States)

    Knapczyk, J.; Kucybała, P.

    2016-09-01

    The paper presents the analysis and optimization of steering system with rack and pinion and McPherson suspension using spatial model and equivalent simplified planar model. The dimension of the steering linkage that give minimum steering error can be estimated using planar model. The steering error is defined as the difference between the actual angle made by the outer front wheel during steering manoeuvers and the calculated angle for the same wheel based on the Ackerman principle. For a given linear rack displacement, a specified steering arms angular displacements are determined while simultaneously ensuring best transmission angle characteristics (i) without and (ii) with imposing linear correlation between input and output. Numerical examples are used to illustrate the proposed method.

  20. Identification of redox-sensitive cysteines in the arabidopsis proteome using OxiTRAQ, a quantitative redox proteomics method

    KAUST Repository

    Liu, Pei

    2014-01-28

    Cellular redox status plays a key role in mediating various physiological and developmental processes often through modulating activities of redox-sensitive proteins. Various stresses trigger over-production of reactive oxygen/nitrogen species which lead to oxidative modifications of redox-sensitive proteins. Identification and characterization of redox-sensitive proteins are important steps toward understanding molecular mechanisms of stress responses. Here, we report a high-throughput quantitative proteomic approach termed OxiTRAQ for identifying proteins whose thiols undergo reversible oxidative modifications in Arabidopsis cells subjected to oxidative stress. In this approach, a biotinylated thiol-reactive reagent is used for differential labeling of reduced and oxidized thiols. The biotin-tagged peptides are affinity purified, labeled with iTRAQ reagents, and analyzed using a paralleled HCD-CID fragmentation mode in an LTQ-Orbitrap. With this approach, we identified 195 cysteine-containing peptides from 179 proteins whose thiols underwent oxidative modifications in Arabidopsis cells following the treatment with hydrogen peroxide. A majority of those redox-sensitive proteins, including several transcription factors, were not identified by previous redox proteomics studies. This approach allows identification of the specific redox-regulated cysteine residues, and offers an effective tool for elucidation of redox proteomes. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Redox-Flow Batteries: From Metals to Organic Redox-Active Materials.

    Science.gov (United States)

    Winsberg, Jan; Hagemann, Tino; Janoschka, Tobias; Hager, Martin D; Schubert, Ulrich S

    2017-01-16

    Research on redox-flow batteries (RFBs) is currently experiencing a significant upturn, stimulated by the growing need to store increasing quantities of sustainably generated electrical energy. RFBs are promising candidates for the creation of smart grids, particularly when combined with photovoltaics and wind farms. To achieve the goal of "green", safe, and cost-efficient energy storage, research has shifted from metal-based materials to organic active materials in recent years. This Review presents an overview of various flow-battery systems. Relevant studies concerning their history are discussed as well as their development over the last few years from the classical inorganic, to organic/inorganic, to RFBs with organic redox-active cathode and anode materials. Available technologies are analyzed in terms of their technical, economic, and environmental aspects; the advantages and limitations of these systems are also discussed. Further technological challenges and prospective research possibilities are highlighted.

  2. Effects of roughage inclusion and particle size on performance and rumination behavior of finishing beef steers.

    Science.gov (United States)

    Gentry, W W; Weiss, C P; Meredith, C M; McCollum, F T; Cole, N A; Jennings, J S

    2016-11-01

    Roughage is typically mechanically processed to increase digestibility and improve handling and mixing characteristics in beef cattle finishing diets. Roughage is fed to promote ruminal health and decrease digestive upset, but inclusion in finishing diets is limited due to the cost per unit of energy. Rumination behavior may be a means to standardize roughage in beef cattle finishing diets, and increasing particle size of roughage may allow a decrease in roughage inclusion without sacrificing animal performance. Therefore, the objectives of this study were to quantify rumination time for a finishing beef animal and to evaluate the effects of corn stalk (CS) inclusion rate and particle size on rumination behavior, animal performance, and carcass characteristics. Fifty-one individually fed steers (385 ± 3.6 kg initial BW) were used in a randomized complete block design feeding study. Corn stalks were passed through a tub grinder equipped with a 7.62-cm screen once to generate long-grind CS (LG-CS) or twice to generate short-grind CS (SG-CS). Dietary treatments were based on steam-flaked corn and included, on a DM basis, 30% wet corn gluten feed (WCGF) with 5% SG-CS (5SG), 30% WCGF with 5% LG-CS (5LG), and 25% WCGF with 10% SG-CS (10SG). The Penn State Particle Separator was used to separate ingredients and treatment diets and to estimate physically effective NDF (peNDF). On d 70, each steer was fitted with a collar (HR Tag; SCR Dairy, Netanya, Isreal), which continuously measured rumination minutes via a sensory microphone. Long-grind CS contained more ( < 0.01) peNDF than SG-CS, and the 10SG diet contained more ( = 0.03) peNDF than the 5LG and 5SG diets. Dry matter intake was greatest ( = 0.03) for steers consuming 5LG and least for steers consuming 10SG, with cattle consuming 5SG being intermediate. Carcass-adjusted ADG and G:F were greatest ( ≤ 0.03) for steers consuming 5LG and 5SG compared with steers consuming 10SG. Hot carcass weight tended ( = 0.10) to be

  3. A redox-neutral catechol synthesis.

    Science.gov (United States)

    Wu, Qian; Yan, Dingyuan; Chen, Ying; Wang, Ting; Xiong, Feng; Wei, Wei; Lu, Yi; Sun, Wei-Yin; Li, Jie Jack; Zhao, Jing

    2017-01-27

    Ubiquitous tyrosinase catalyses the aerobic oxidation of phenols to catechols through the binuclear copper centres. Here, inspired by the Fischer indole synthesis, we report an iridium-catalysed tyrosinase-like approach to catechols, employing an oxyacetamide-directed C-H hydroxylation on phenols. This method achieves one-step, redox-neutral synthesis of catechols with diverse substituent groups under mild conditions. Mechanistic studies confirm that the directing group (DG) oxyacetamide acts as the oxygen source. This strategy has been applied to the synthesis of different important catechols with fluorescent property and bioactivity from the corresponding phenols. Finally, our method also provides a convenient route to (18)O-labelled catechols using (18)O-labelled acetic acid.

  4. Zinc-redox battery: A technology update

    Science.gov (United States)

    Hollandsworth, R. P.

    Since 1977, scientists at Lockheed Missiles and Space Company, Inc., have been developing the Zinc-Redox Battery for large-scale electrical energy storage. The current state of technology for this battery has demonstrated a number of positive features: (1) high energy efficiency (82.6 +/- 4.4%) demonstrated for more than 754 cycles with a low-cost alpha-methyl styrene membrane; (2) minimal environmental concerns because the only toxic reactant is 2N sodium hydroxide, and thus low projected balance-of-plant costs; and (3) good cell performance over a wide range of discharge rates with cell IR being the main determinant of energy efficiency. Current studies have focused on zinc electrode performance parameters, high current density discharge evaluation, and low-cost membrane cycle-life performance.

  5. Iron-sulfide redox flow batteries

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Guanguang; Yang, Zhenguo; Li, Liyu; Kim, Soowhan; Liu, Jun; Graff, Gordon L

    2016-06-14

    Iron-sulfide redox flow battery (RFB) systems can be advantageous for energy storage, particularly when the electrolytes have pH values greater than 6. Such systems can exhibit excellent energy conversion efficiency and stability and can utilize low-cost materials that are relatively safer and more environmentally friendly. One example of an iron-sulfide RFB is characterized by a positive electrolyte that comprises Fe(III) and/or Fe(II) in a positive electrolyte supporting solution, a negative electrolyte that comprises S.sup.2- and/or S in a negative electrolyte supporting solution, and a membrane, or a separator, that separates the positive electrolyte and electrode from the negative electrolyte and electrode.

  6. Hybrid anodes for redox flow batteries

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wei; Xiao, Jie; Wei, Xiaoliang; Liu, Jun; Sprenkle, Vincent L.

    2015-12-15

    RFBs having solid hybrid electrodes can address at least the problems of active material consumption, electrode passivation, and metal electrode dendrite growth that can be characteristic of traditional batteries, especially those operating at high current densities. The RFBs each have a first half cell containing a first redox couple dissolved in a solution or contained in a suspension. The solution or suspension can flow from a reservoir to the first half cell. A second half cell contains the solid hybrid electrode, which has a first electrode connected to a second electrode, thereby resulting in an equipotential between the first and second electrodes. The first and second half cells are separated by a separator or membrane.

  7. High energy density redox flow device

    Energy Technology Data Exchange (ETDEWEB)

    Carter, W. Craig; Chiang, Yet-Ming; Duduta, Mihai; Limthongkul, Pimpa

    2017-04-04

    Redox flow devices are described including a positive electrode current collector, a negative electrode current collector, and an ion-permeable membrane separating said positive and negative current collectors, positioned and arranged to define a positive electroactive zone and a negative electroactive zone; wherein at least one of said positive and negative electroactive zone comprises a flowable semi-solid composition comprising ion storage compound particles capable of taking up or releasing said ions during operation of the cell, and wherein the ion storage compound particles have a polydisperse size distribution in which the finest particles present in at least 5 vol % of the total volume, is at least a factor of 5 smaller than the largest particles present in at least 5 vol % of the total volume.

  8. A redox-neutral catechol synthesis

    Science.gov (United States)

    Wu, Qian; Yan, Dingyuan; Chen, Ying; Wang, Ting; Xiong, Feng; Wei, Wei; Lu, Yi; Sun, Wei-Yin; Li, Jie Jack; Zhao, Jing

    2017-01-01

    Ubiquitous tyrosinase catalyses the aerobic oxidation of phenols to catechols through the binuclear copper centres. Here, inspired by the Fischer indole synthesis, we report an iridium-catalysed tyrosinase-like approach to catechols, employing an oxyacetamide-directed C-H hydroxylation on phenols. This method achieves one-step, redox-neutral synthesis of catechols with diverse substituent groups under mild conditions. Mechanistic studies confirm that the directing group (DG) oxyacetamide acts as the oxygen source. This strategy has been applied to the synthesis of different important catechols with fluorescent property and bioactivity from the corresponding phenols. Finally, our method also provides a convenient route to 18O-labelled catechols using 18O-labelled acetic acid.

  9. Iron-sulfide redox flow batteries

    Science.gov (United States)

    Xia, Guan-Guang; Yang, Zhenguo; Li, Liyu; Kim, Soowhan; Liu, Jun; Graff, Gordon L

    2013-12-17

    Iron-sulfide redox flow battery (RFB) systems can be advantageous for energy storage, particularly when the electrolytes have pH values greater than 6. Such systems can exhibit excellent energy conversion efficiency and stability and can utilize low-cost materials that are relatively safer and more environmentally friendly. One example of an iron-sulfide RFB is characterized by a positive electrolyte that comprises Fe(III) and/or Fe(II) in a positive electrolyte supporting solution, a negative electrolyte that comprises S.sup.2- and/or S in a negative electrolyte supporting solution, and a membrane, or a separator, that separates the positive electrolyte and electrode from the negative electrolyte and electrode.

  10. Economics of vanadium redox flow battery membranes

    Science.gov (United States)

    Minke, Christine; Turek, Thomas

    2015-07-01

    The membrane is a key component of the vanadium redox flow battery (VRFB) in terms of electrochemical performance as well as costs. The standard material Nafion® is cost intensive and therefore several alternative materials are in the focus of research. In this paper a substantial analytical approach is presented in order to quantify bottom price limits for different types of membranes. An in-depth analysis of material and production cost allows statements concerning cost potentials of different ion exchange membranes (IEM) and nano filtration membranes (NFM). The final result reveals that expected costs of IEM and NFM at high production volumes differ by one order of magnitude. Moreover, an analysis of the current market situation is made to provide a framework for economic considerations at present.

  11. Late Ediacaran redox stability and metazoan evolution

    Science.gov (United States)

    Johnston, D. T.; Poulton, S. W.; Goldberg, T.; Sergeev, V. N.; Podkovyrov, V.; Vorob'eva, N. G.; Bekker, A.; Knoll, A. H.

    2012-06-01

    The Neoproterozoic arrival of animals fundamentally changed Earth's biological and geochemical trajectory. Since the early description of Ediacaran and Cambrian animal fossils, a vigorous debate has emerged about the drivers underpinning their seemingly rapid radiation. Some argue for predation and ecology as central to diversification, whereas others point to a changing chemical environment as the trigger. In both cases, questions of timing and feedbacks remain unresolved. Through these debates, the last fifty years of work has largely converged on the concept that a change in atmospheric oxygen levels, perhaps manifested indirectly as an oxygenation of the deep ocean, was causally linked to the initial diversification of large animals. What has largely been absent, but is provided in this study, is a multi-proxy stratigraphic test of this hypothesis. Here, we describe a coupled geochemical and paleontological investigation of Neoproterozoic sedimentary rocks from northern Russia. In detail, we provide iron speciation data, carbon and sulfur isotope compositions, and major element abundances from a predominantly siliciclastic succession (spanning>1000 m) sampled by the Kel'tminskaya-1 drillcore. Our interpretation of these data is consistent with the hypothesis that the pO2 threshold required for diversification of animals with high metabolic oxygen demands was crossed prior to or during the Ediacaran Period. Redox stabilization of shallow marine environments was, however, also critical and only occurred about 560 million years ago (Ma), when large motile bilaterians first enter the regional stratigraphic record. In contrast, neither fossils nor geochemistry lend support to the hypothesis that ecological interactions altered the course of evolution in the absence of environmental change. Together, the geochemical and paleontological records suggest a coordinated transition from low oxygen oceans sometime before the Marinoan (˜635 Ma) ice age, through better

  12. Experimental model and analytic solution for real-time observation of vehicle's additional steer angle

    Science.gov (United States)

    Zhang, Xiaolong; Li, Liang; Pan, Deng; Cao, Chengmao; Song, Jian

    2014-03-01

    The current research of real-time observation for vehicle roll steer angle and compliance steer angle(both of them comprehensively referred as the additional steer angle in this paper) mainly employs the linear vehicle dynamic model, in which only the lateral acceleration of vehicle body is considered. The observation accuracy resorting to this method cannot meet the requirements of vehicle real-time stability control, especially under extreme driving conditions. The paper explores the solution resorting to experimental method. Firstly, a multi-body dynamic model of a passenger car is built based on the ADAMS/Car software, whose dynamic accuracy is verified by the same vehicle's roadway test data of steady static circular test. Based on this simulation platform, several influencing factors of additional steer angle under different driving conditions are quantitatively analyzed. Then ɛ-SVR algorithm is employed to build the additional steer angle prediction model, whose input vectors mainly include the sensor information of standard electronic stability control system(ESC). The method of typical slalom tests and FMVSS 126 tests are adopted to make simulation, train model and test model's generalization performance. The test result shows that the influence of lateral acceleration on additional steer angle is maximal (the magnitude up to 1°), followed by the longitudinal acceleration-deceleration and the road wave amplitude (the magnitude up to 0.3°). Moreover, both the prediction accuracy and the calculation real-time of the model can meet the control requirements of ESC. This research expands the accurate observation methods of the additional steer angle under extreme driving conditions.

  13. Peroxiredoxin 3 levels regulate a mitochondrial redox setpoint in malignant mesothelioma cells

    Directory of Open Access Journals (Sweden)

    Brian Cunniff

    2014-01-01

    Full Text Available Peroxiredoxin 3 (PRX3, a typical 2-Cys peroxiredoxin located exclusively in the mitochondrial matrix, is the principal peroxidase responsible for metabolizing mitochondrial hydrogen peroxide, a byproduct of cellular respiration originating from the mitochondrial electron transport chain. Mitochondrial oxidants are produced in excess in cancer cells due to oncogenic transformation and metabolic reorganization, and signals through FOXM1 and other redox-responsive factors to support a hyper-proliferative state. Over-expression of PRX3 in cancer cells has been shown to counteract oncogene-induced senescence and support tumor cell growth and survival making PRX3 a credible therapeutic target. Using malignant mesothelioma (MM cells stably expressing shRNAs to PRX3 we show that decreased expression of PRX3 alters mitochondrial structure, function and cell cycle kinetics. As compared to control cells, knockdown of PRX3 expression increased mitochondrial membrane potential, basal ATP production, oxygen consumption and extracellular acidification rates. shPRX3 MM cells failed to progress through the cell cycle compared to wild type controls, with increased numbers of cells in G2/M phase. Diminished PRX3 expression also induced mitochondrial hyperfusion similar to the DRP1 inhibitor mdivi-1. Cell cycle progression and changes in mitochondrial networking were rescued by transient expression of either catalase or mitochondrial-targeted catalase, indicating high levels of hydrogen peroxide contribute to perturbations in mitochondrial structure and function in shPRX3 MM cells. Our results indicate that PRX3 levels establish a redox set point that permits MM cells to thrive in response to increased levels of mROS, and that perturbing the redox status governed by PRX3 impairs proliferation by altering cell cycle-dependent dynamics between mitochondrial networking and energy metabolism.

  14. Polyoxometalate active charge-transfer material for mediated redox flow battery

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Travis Mark; Hudak, Nicholas; Staiger, Chad; Pratt, Harry

    2017-01-17

    Redox flow batteries including a half-cell electrode chamber coupled to a current collecting electrode are disclosed herein. In a general embodiment, a separator is coupled to the half-cell electrode chamber. The half-cell electrode chamber comprises a first redox-active mediator and a second redox-active mediator. The first redox-active mediator and the second redox-active mediator are circulated through the half-cell electrode chamber into an external container. The container includes an active charge-transfer material. The active charge-transfer material has a redox potential between a redox potential of the first redox-active mediator and a redox potential of the second redox-active mediator. The active charge-transfer material is a polyoxometalate or derivative thereof. The redox flow battery may be particularly useful in energy storage solutions for renewable energy sources and for providing sustained power to an electrical grid.

  15. A nano switch mechanism for the redox-responsive sulfotransferase.

    Science.gov (United States)

    Lin, Chih-Heng; Lin, En-Shyh; Su, Tian-Mu; Hung, Kuo-Sheng; Yang, Yuh-Shyong

    2012-07-15

    Cellular redox signaling is important in diverse physiological and pathological processes. The activity of rat phenol sulfotransferase (rSULT1A1), which is important for the metabolism of hormone and drug, is subjected to redox regulation. Two cysteines, Cys232 and Cys66, nanometer away from each other and from the enzyme active site were proposed to form disulfide bond to regulate the activity of rSULT1A1. A nano switch, composed of a flexible loop from amino acid residues 59-70, explained how this long distance interaction between two cysteines can be achieved. The enzyme properties were investigated through site-directed muatagnesis, circular dichroism, enzyme kinetics and homologous modeling of the rSULT1A1 structures. We proposed that the formation of disulfide bond between Cys232 and Cys66 induced conformational changes of sulfotransferase, then in turn affected its nucleotide binding and enzyme activity. This discovery was extended to understand the possible redox regulation of other sulfotransferases from different organisms. The redox switch can be created in other redox-insensitive sulfotransferases, such as human phenol sulfotransferase (hSULT1A1) and human alcohol sulfotransferase (hSULT2A1), to produce mutant enzymes with redox regulation capacity. This study strongly suggested that redox regulation of drug and hormone metabolism can be significantly varied even though the sequence and structure of SULT1A1 of human and rat have a high degree of homology.

  16. 基于主动转向干预的EPS系统转向盘力矩突变修正策略%Correction Strategy of Steering Wheel Torque for EPS System Based on Intervention of Active Steering

    Institute of Scientific and Technical Information of China (English)

    魏建伟; 魏民祥

    2011-01-01

    在研究融合主动转向功能的电动助力转向系统实现原理的基础上,分析转向系统的力矩和角位移传递特性.针对主动转向干预时转向盘力矩发生突变的问题,提出一种适用于全车速范围的助力电机前馈助力修正策略.为验证所提出的前馈助力修正策略的修正效果,进行主动转向干预时转向盘力矩阶跃仿真试验.仿真结果表明:该策略有效地削弱了伴随主动转向干预同时出现的转向盘力矩突变,且在高速时该修正策略仍然有效,改善了主动转向干预时转向系统的转向路感.%Implementation principle of an electric power steering (EPS) system integrated with active steering function is researched based on which transfer characteristics of torque and angle displacement for steering system are analyzed. To avoid mutations of steering wheel torque during the interference of active steering, a feed-forward assistant torque correction strategy for assist motor is presented? which can be used in the whole speed range. To verify the performance of the proposed correction strategy, step simulation tests of steering wheel torque during the interference of active steering are carried out. Simulation results indicate that mutations of steering wheel torque are reduced, the correction strategy can still be effective at high speed, and steering sense of the steering system during the interference of active steering is improved.

  17. Redox mechanisms in hepatic chronic wound healing and fibrogenesis

    Directory of Open Access Journals (Sweden)

    Novo Erica

    2008-10-01

    Full Text Available Abstract Reactive oxygen species (ROS generated within cells or, more generally, in a tissue environment, may easily turn into a source of cell and tissue injury. Aerobic organisms have developed evolutionarily conserved mechanisms and strategies to carefully control the generation of ROS and other oxidative stress-related radical or non-radical reactive intermediates (that is, to maintain redox homeostasis, as well as to 'make use' of these molecules under physiological conditions as tools to modulate signal transduction, gene expression and cellular functional responses (that is, redox signalling. However, a derangement in redox homeostasis, resulting in sustained levels of oxidative stress and related mediators, can play a significant role in the pathogenesis of major human diseases characterized by chronic inflammation, chronic activation of wound healing and tissue fibrogenesis. This review has been designed to first offer a critical introduction to current knowledge in the field of redox research in order to introduce readers to the complexity of redox signalling and redox homeostasis. This will include ready-to-use key information and concepts on ROS, free radicals and oxidative stress-related reactive intermediates and reactions, sources of ROS in mammalian cells and tissues, antioxidant defences, redox sensors and, more generally, the major principles of redox signalling and redox-dependent transcriptional regulation of mammalian cells. This information will serve as a basis of knowledge to introduce the role of ROS and other oxidative stress-related intermediates in contributing to essential events, such as the induction of cell death, the perpetuation of chronic inflammatory responses, fibrogenesis and much more, with a major focus on hepatic chronic wound healing and liver fibrogenesis.

  18. DNA repair and redox activities and inhibitors of apurinic/apyrimidinic endonuclease 1/redox effector factor 1 (APE1/Ref-1): a comparative analysis and their scope and limitations toward anticancer drug development.

    Science.gov (United States)

    Kaur, Gagandeep; Cholia, Ravi P; Mantha, Anil K; Kumar, Raj

    2014-12-26

    The apurinic/apyrimidinic endonuclease 1/redox effector factor 1 (APE1/Ref-1) is a multifunctional enzyme involved in DNA repair and activation of transcription factors through its redox function. The evolutionarily conserved C- and N-termini are involved in these functions independently. It is also reported that the activity of APE1/Ref-1 abruptly increases several-fold in various human cancers. The control over the outcomes of these two functions is emerging as a new strategy to combine enhanced DNA damage and chemotherapy in order to tackle the major hurdle of increased cancer cell growth and proliferation. Studies have targeted these two domains individually for the design and development of inhibitors for APE1/Ref-1. Here, we have made, for the first time, an attempt at a comparative analysis of APE1/Ref-1 inhibitors that target both DNA repair and redox activities simultaneously. We further discuss their scope and limitations with respect to the development of potential anticancer agents.

  19. Changes in portal blood metabolites and insulin with feeding steers twice daily.

    Science.gov (United States)

    Chase, L E; Wangsness, P J; Kavanaugh, J F; Griel, L C; Gahagan, J H

    1977-03-01

    Four Holstein steers surgically prepared with a device for sampling from the portal vein were used to examine changes in concentrations of metabolites and insulin in portal blood with scheduled meals. The animals were fed a complete mixed ration (3.4 kcal/g digestible energy) twice daily at three intakes. Blood was sampled at 30, 15, 10, and 5 min before feeding and at 1, 3, 5, 10, 15, 30, 45, 60, and 120 min after feeding began. Average intakes of food at 30 min for the three intakes were 0 (control), 889 g (restricted), and 1425 g (fed). Packed cell volume increased rapidly within 15 min of initiation of the meal in fed steers, but the maximum change from pre-feeding was 6.6%. Insulin increased within 5 min with the restricted intake and at 15 min in fed steers. Portal volatile fatty acids and beta-hydroxybutyrate also increased within 15 min of initiation of the meal in fed steers, and glucose tended to decrease after feeding. Certain metabolites and insulin of portal bood changed rapidly with feeding. Additional studies are required to establish any role of these blood components in the short-term control of feed intake in steers consuming concentrate feeds.

  20. Controller Design for Electric Power Steering System Using T-S Fuzzy Model Approach

    Institute of Scientific and Technical Information of China (English)

    Xin Li; Xue-Ping Zhao; Jie Chen

    2009-01-01

    Pressure ripples in electric power steering (EPS) systems can be caused by the phase lag between the driver's steering torque and steer angle, the nonlinear frictions, and the disturbances from road and sensor noise especially during high-frequency maneuvers. This paper investigates the use of the robust fuzzy control method for actively reducing pressure ripples for EPS systems. Remarkable progress on steering maneuverability is achieved. The EPS dynamics is described with an eight-order nonlinear state-space model and approximated by a Takagi-Sugeno (T-S) fuzzy model with time-varying delays and external disturbances. A stabilization approach is then presented for nonlinear time-delay systems through fuzzy state feedback controller in parallel distributed compensation (PDC) structure. The closed-loop stability conditions of EPS system with the fuzzy controller are parameterized in terms of the linear matrix inequality (LMI) problem. Simulations and experiments using the proposed robust fuzzy controller and traditional PID controller have been carried out for EPS systems. Both the simulation and experiment results show that the proposed fuzzy controller can reduce the torque ripples and allow us to have a good steering feeling and stable driving.