WorldWideScience

Sample records for responsible metals supply

  1. Responsive supply chain: modeling and simulation

    Directory of Open Access Journals (Sweden)

    Amit Kumar Sinha

    2015-06-01

    Full Text Available Unexpected occurrence like natural calamity, abruptly change in customer demands, upgradation of technologies, necessity of compatible suppliers etc. is the most challenging issues even for efficient global supply chain management. Therefore, modeling of responsive supply chain is an emerging technology for sustaining any firm/industry in future competitive environment. In this paper, an attempt has been made to not only analyze the performance of efficient supply chain management but also how to improve the performance of existing supply chain with the objective of developing a modeling of responsive supply chain management. The complexity of the model is also highlighted with the help of numerical example. This paper also explores the possibility to mathematical modeling of the responsive supply chain which will be an emerging topic for researchers and practitioners. The modeling of responsive supply chain can be employed as a competitive strategy for e-commerce, green supply chain, and compatible supplier selection problem. The another salient feature of this paper is that a distinct comparative literature review of the lean, agile, efficient, and responsive supply chain management has been presented.

  2. IEA Response System for Oil Supply Emergencies

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-12-15

    Emergency response to oil supply disruptions has remained a core mission of the International Energy Agency since its founding in 1974. This information pamphlet explains the decisionmaking process leading to an IEA collective action, the measures available -- focusing on stockdraw -- and finally, the historical background of major oil supply disruptions and the IEA response to them. It also demonstrates the continuing need for emergency preparedness, including the growing importance of engaging key transition and emerging economies in dialogue about energy security.

  3. IEA Response System for Oil Supply Emergencies

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-15

    Emergency response to oil supply disruptions has remained a core mission of the International Energy Agency since its founding in 1974. This information pamphlet explains the decisionmaking process leading to an IEA collective action, the measures available -- focusing on stockdraw -- and finally, the historical background of major oil supply disruptions and the IEA response to them. It also demonstrates the continuing need for emergency preparedness, including the growing importance of engaging key transition and emerging economies in dialogue about energy security.

  4. Corporate Social Responsibility and Supply Chain Management:

    DEFF Research Database (Denmark)

    Liempd, Dennis van; Warming-Rasmussen, Bent; Abild-Nielsen, Jens

      The last 25 years or so, two disciplines have become increasingly more prominent in business: Supply Chain Management (SCM) and Corporate Social Responsibility (CSR). Traditionally, SCM has been characterized by concerns of efficiency and effectiveness, illustrated by the 7 R's: the right product....... Since a supply chain exists of legally independent entities, the need for right ethics creates the need for a ninth R: right monitoring. This paper investigates how the discipline of auditing can contribute to solve the problem of right monitoring of right ethics across a supply chain. In order to do...... concludes that the independent auditor's methods can contribute in many ways to develop a new form of auditing: Supply Chain Audits (SC-A). The paper ends with implications for future research....

  5. Corporate Social Responsibility and Supply Chain Management:

    DEFF Research Database (Denmark)

    Liempd, Dennis van; Warming-Rasmussen, Bent; Abild-Nielsen, Jens

      The last 25 years or so, two disciplines have become increasingly more prominent in business: Supply Chain Management (SCM) and Corporate Social Responsibility (CSR). Traditionally, SCM has been characterized by concerns of efficiency and effectiveness, illustrated by the 7 R's: the right product...

  6. Agricultural productivity and supply responses in Ghana

    OpenAIRE

    2012-01-01

    The importance of Agricultural Supply Response (ASR) modelling cannot be over emphasised. Knowledge of its size provides a roadmap for designing a tailored agricultural policy based on suppliers’ responses to price and non-price incentives. In spite of its policy importance, limited amount of studies exist for Ghana. This study seeks to fill the gap and also sheds some light on how future agricultural policies in Ghana should be formulated. This study is conducted on a regional (ecologic...

  7. Establishment of responsible supply chain: processes standardization

    Directory of Open Access Journals (Sweden)

    V.A. Falovych

    2016-06-01

    Full Text Available The aim of the article. It is established the need to implement activities of the concept of sustainable development at Ukrainian industrial enterprises, due to their access to external markets, especially markets of the European Union. This process involves the use of extended responsibility principles in enterprise management, which is aimed at organic combination of economic objectives with good social environment. The increasing of manufacturing enterprise as the leading element of supply chain is interested in using of extended principles of accountability by all participants of supply chain, particularly suppliers, which has direct impact on the characteristics of final product and customer satisfaction. The results of the analysis. It is actualized the problem of criteria developing for cooperation with suppliers, establishing requirements for economic, social and ecological direction in the form of relevant documents, codeсs and selection criteria. It is proved that standardization process of selecting suppliers, developing criteria for their evaluation will provide training of responsible supply chain, facilitate the introduction of monitoring their activities in the economic, social and environmental spheres. It was established that the selection of suppliers, subcontractors or business partners is based on many criteria. More often they are specified in the policies and procedures of procurement. In the concluded agreements it is established a significant addition to the terms of cooperation, prices, timeliness and quality of supply. There are such implementing tools: survey of suppliers, development of special environmental and social policies, codes of conduct, contractual provisions and standards of ISO and SA8000, etc. Ensuring the implementation of the principles of responsibility in the enterprise activity requires certain costs, so the standardization process of vendor selecting will reduce the overall costs associated with

  8. Mineral supply constraints necessitate a global policy response

    Science.gov (United States)

    Nickless, Edmund

    2016-04-01

    Adoption on 12 December 2015 of The Paris Agreement, the first universal climate agreement, suggests that nations will invest in infrastructures for renewable energy sources paving the way to a global low-carbon society. These large-scale changes will require vast amounts of metals and minerals. Regardless of whether known supplies are enough to meet demand in the near future, efforts must be made now to forestall unpredictable yet inevitable supply shortages in the decades to come, shortages that would dramatically impact the building of additional generation and distribution capacity, and deployment of low-carbon technology. But in response to the current downturn in commodity prices, the global mining industry is downsizing and reducing investment in the new exploration, putting at risk future security of supply. Mining and climate change are inextricably linked; the new adaptive technologies needed to tackle climate change depend on extraction of minerals and metals. An interdisciplinary group supported by the International Union of Geological Sciences, the International Council for Science Unions and UNESCO proposes measures to avert the looming minerals crisis that is developing in the context of current recycling capacity and exploration trends. Our immediate goal is to stimulate discussion of supply constraints using available data on mineral reserves. We build on recent discussions of supply risk and criticality with a focus on the source of primary resources over the next two to three decades when the availability of metals for recycling will remain low. Current massive production of iron ore and other such commodities despite record low prices indicates a failure of the traditional supply and demand constraints. Broader discussions of metal and mineral supply beyond current criticality are needed given the pace of technological and demographic change as well as rapid development spurts. Furthermore, accessible mineral deposits are irregularly distributed

  9. Labour supply responses to paid parental leave

    OpenAIRE

    Karimi, Arizo; Lindahl, Erica; Skogman Thoursie , Peter

    2012-01-01

    Women account for the majority of parental leave take-up, which is likely one of the major reasons for the gender gap in income and wages. Consequently, many countries exert effort to promote a more gender equal division of parental leave. Indeed, the last decades have seen an increase in fathers’ take-up of parental leave benefits, but the gender earnings gap has remained fairly constant. In this paper we re-evaluate the labour supply responses of both mothers and fathers to three major refo...

  10. Ablation response testing of aerospace power supplies

    Science.gov (United States)

    Lutz, S. A.; Chan, C. C.

    1993-01-01

    An experimental program was performed to assess the aerothermal ablation response of aerospace power supplies. Full-scale General Purpose Heat Source (GPHS) test articles, Graphite Impact Shell (GIS) test articles, and Lightweight Radioisotope Heater Unit (LWRHU) test articles were all tested without nuclear fuel in simulated reentry environments at the NASA Ames Research Center. Stagnation heating, stagnation pressure, stagnation surface temperature, stagnation surface recession profile, and weight loss measurements were obtained for diffusion-limited and sublimation ablation conditions. The recession profile and weight loss measurements showed an effect of surface features on the stagnation face. The surface features altered the local heating which in turn affected the local ablation.

  11. A dynamic perspective of the geopolitical supply risk of metals

    DEFF Research Database (Denmark)

    Habib, Komal; Hamelin, Lorie; Wenzel, Henrik

    2016-01-01

    Metals are distributed in the earth's crust in varying amounts and ore concentrations, implying that some countries have more metal resources than others. This inequality in geological resource distribution may lead to potential constraints and bottlenecks of a steady resource supply. In the cont...... production distribution and more dependent on the location of current geological resources and the future discoveries, as well as on the technological development to improve profitability of mining the currently sub-economical resources....... risk of mineral resources. The aim of this study is to present a historical overview of the development in geopolitical supply risk of 52 metals during the past two decades and to support an assessment of such risk in the future, i.e. 2050. A geographical mapping of metals primary production in 1994...... and 2013 is included which shows a shift from developed economies to developing economies over this time period. Our analysis demonstrates that the geopolitical supply risk of metals has been fluctuating during the past two decades due to change in the number and production share of producing countries...

  12. Planning the bioterrorism response supply chain: learn and live.

    Science.gov (United States)

    Brandeau, Margaret L; Hutton, David W; Owens, Douglas K; Bravata, Dena M

    2007-01-01

    Responses to bioterrorism require rapid procurement and distribution of medical and pharmaceutical supplies, trained personnel, and information. Thus, they present significant logistical challenges. On the basis of a review of the manufacturing and service supply chain literature, the authors identified five supply chain strategies that can potentially increase the speed of response to a bioterrorism attack, reduce inventories, and save money: effective supply chain network design; effective inventory management; postponement of product customization and modularization of component parts; coordination of supply chain stakeholders and appropriate use of incentives; and effective information management. The authors describe how concepts learned from published evaluations of manufacturing and service supply chains, as well as lessons learned from responses to natural disasters, naturally occurring outbreaks, and the 2001 US anthrax attacks, can be applied to design, evaluate, and improve the bioterrorism response supply chain. Such lessons could also be applied to the response supply chains for disease outbreaks and natural and manmade disasters.

  13. Beef Supply Response Under Uncertainty: An Autoregressive Distributed Lag Model

    OpenAIRE

    Mbaga, Msafiri Daudi; Coyle, Barry T.

    2003-01-01

    This is the first econometric study of dynamic beef supply response to incorporate risk aversion or, more specifically, price variance. Autoregressive distributed lag (ADL) models are estimated for cow-calf and feedlot operations using aggregate data for Alberta. In all cases, output price variance has a negative impact on output supply and investment. Moreover, the impacts of expected price on supply response are greater in magnitude and significance than in risk-neutral models.

  14. Responsiveness and flexibility in a Decentralized Supply Chain

    DEFF Research Database (Denmark)

    Petersen, Kristian Rasmus; Bilberg, Arne; Hadar, Ronen

    Today’s supply chains are not capable of managing the instabilities that is the case in the market. Instead, there is a need to develop supply chains that are capable of adapting to changes. Through a case study of LEGO, the authors suggest a possible solution: a decentralized supply chain serving...... independent and self-sufficient local factories. The decentralized supply chain is provided with materials, parts and pre-assembled elements from local suppliers and supplies the local market in return. Keywords: Decentralize, Responsiveness, Flexibility...

  15. Marketing potential of corporate social responsibility in supply chains

    NARCIS (Netherlands)

    Verhees, F.J.H.M.; Kuipers, A.; Meulenberg, M.T.G.

    2008-01-01

    This paper provides a method to assess the customer value and marketing possibilities of increasing transparency about the corporate social responsibility (CSR) of supply chains. The willingness of small firms, in this study farmers in food supply chains, to make information available about certain

  16. EMERGENCY RESPONSE FOR PUBLIC WATER SUPPLIES AFTER HURRICANE KATRINA

    Science.gov (United States)

    Hurricane Katrina resulted in damage and destruction to local water supplies in Mississippi and Louisiana affecting millions of people. Immediately following the devastation, a multidisciplinary team of 30 EPA emergency response, research, and water program personnel joined force...

  17. IEA Response System for Oil Supply Emergencies (2012 update)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-09-05

    Emergency response to oil supply disruptions has remained a core mission of the International Energy Agency since its founding in 1974. This information pamphlet explains the decisionmaking process leading to an IEA collective action, the measures available -- focusing on stockdraw -- and finally, the historical background of major oil supply disruptions and the IEA response to them. It also demonstrates the continuing need for emergency preparedness, including the growing importance of engaging key transition and emerging economies in dialogue about energy security.

  18. Oil supply security -- Emergency response of IEA countries 2007

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-11-29

    When Hurricane Katrina hit the Gulf of Mexico in 2005, the region's oil production and refining infrastructure was devastated and world energy markets were disrupted. The International Energy Agency decided in a matter of days to bring 60 million barrels of additional oil to the market. The emergency response system worked - the collective action helped to stabilise global markets. Since its founding in 1974, oil supply security has been a core mission of the IEA and the Agency has improved its mechanisms to respond to short-term oil supply disruptions. Nevertheless, numerous factors will continue to test the delicate balance of supply and demand. Oil demand growth will continue to accelerate in Asia; oil will be increasingly produced by a shrinking number of countries; and capacities in the supply chain will need to expand. These are just a few of the challenges facing an already tight market. What are the emergency response systems of IEA countries? How are their emergency structures organised? How prepared is the IEA to deal with an oil supply disruption? This publication addresses these questions. It presents another cycle of rigorous reviews of the emergency response mechanisms of IEA member countries. The goal of these reviews is to ensure that the IEA stays ready to respond effectively to oil supply disruptions. This publication also includes overviews of how China, India and countries of Southeast Asia are progressing with domestic policies to improve oil supply security, based on emergency stocks.

  19. A dynamic perspective of the geopolitical supply risk of metals

    DEFF Research Database (Denmark)

    Habib, Komal; Hamelin, Lorie; Wenzel, Henrik

    2016-01-01

    . In the context of strategic planning and innovation, and in scientific literature, this aspect is often referred to as geopolitical supply risk. In the past few decades, cobalt crisis, the oil embargo, and the more recent Rare Earth Elements (REEs) issue are the best examples regarding the geopolitical supply...

  20. Assessing responsiveness of a volatile and seasonal supply chain

    DEFF Research Database (Denmark)

    Wong, Chee Yew; Arlbjørn, Jan Stentoft; Hvolby, Hans Henrik

    2006-01-01

    . Assessment of the company’s product differentiation model shows that toy products are mostly innovative or ‘‘intermediate’’, but not functional. A proposed new product differentiation model using risk-influencing determinants has enabled the toy company to differentiate its new products, to deal...... ‘‘market responsive’’ and ‘‘physically efficient’’ supply chains constitutes the backbone of this assessment. Four risk-influencing determinants—forecast uncertainty, demand variability, contribution margin, and time window of delivery are found suitable to assess the responsiveness of the toy supply chain......This paper describes a structural approach to assess the responsiveness of a volatile and seasonal supply chain. It is based on a case study in an international toy company. Fisher’s (Harvard Bus. Rev. 75(2) (1997) 105–117) Model of ‘‘innovative’’ and ‘‘functional’’ products and the corresponding...

  1. Monitoring water supply systems for anomaly detection and response

    NARCIS (Netherlands)

    Bakker, M.; Lapikas, T.; Tangena, B.H.; Vreeburg, J.H.G.

    2012-01-01

    Water supply systems are vulnerable to damage caused by unintended or intended human actions, or due to aging of the system. In order to minimize the damages and the inconvenience for the customers, a software tool was developed to detect anomalies at an early stage, and to support the responsible s

  2. Supply and demand of some critical metals and present status of their recycling in WEEE.

    Science.gov (United States)

    Zhang, Shengen; Ding, Yunji; Liu, Bo; Chang, Chein-Chi

    2017-07-01

    New development and technological innovations make electrical and electronic equipment (EEE) more functional by using an increasing number of metals, particularly the critical metals (e.g. rare and precious metals) with specialized properties. As millions of people in emerging economies adopt a modern lifestyle, the demand for critical metals is soaring. However, the increasing demand causes the crisis of their supply because of their simple deficiency in the Earth's crust or geopolitical constraints which might create political issues for their supply. This paper focuses on the sustainable supply of typical critical metals (indium, rare earth elements (REEs), lithium, cobalt and precious metals) through recycling waste electrical and electronic equipment (WEEE). To illuminate this issue, the production, consumption, expected future demand, current recycling situation of critical metals, WEEE management and their recycling have been reviewed. We find that the demand of indium, REEs, lithium and cobalt in EEE will continuously increasing, while precious metals are decreasing because of new substitutions with less or even without precious metals. Although the generation of WEEE in 2014 was about 41.9 million tons (Mt), just about 15% (6.5 Mt) was treated environmentally. The inefficient collection of WEEE is the main obstacle to relieving the supply risk of critical metals. Furthermore, due to the widespread use in low concentrations, such as indium, their recycling is not just technological problem, but economic feasibility is. Finally, relevant recommendations are point out to address these issues. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Supply chain carbon footprinting and responsibility allocation under emission regulations.

    Science.gov (United States)

    Chen, Jin-Xiao; Chen, Jian

    2017-03-01

    Reduction of greenhouse gas emissions has become an enormous challenge for any single enterprise and its supply chain because of the increasing concern on global warming. This paper investigates carbon footprinting and responsibility allocation for supply chains involved in joint production. Our study is conducted from the perspective of a social planner who aims to achieve social value optimization. The carbon footprinting model is based on operational activities rather than on firms because joint production blurs the organizational boundaries of footprints. A general model is proposed for responsibility allocation among firms who seek to maximize individual profits. This study looks into ways for the decentralized supply chain to achieve centralized optimality of social value under two emission regulations. Given a balanced allocation for the entire supply chain, we examine the necessity of over-allocation to certain firms under specific situations and find opportunities for the firms to avoid over-allocation. The comparison of the two regulations reveals that setting an emission standard per unit of product will motivate firms to follow the standard and improve their emission efficiencies. Hence, a more efficient and promising policy is needed in contrast to existing regulations on total production.

  4. Nonferrous Metals Industry Kicked off Supply Side Reform

    Institute of Scientific and Technical Information of China (English)

    2016-01-01

    On December 1,a"Joint Proposal of Backbone Copper Smelting Enterprises in China"signed by 10 enterprises including Jiangxi Copper Company Limited,Tongling Nonferrous Metals,Yunnan Copper,and Jinchuan Group was formally published on www.cnmc.com.cn,the 10 copper enterprises taking part in this time’s joint production cut have a combined

  5. Ablation response testing of simulated radioisotope power supplies

    Science.gov (United States)

    Lutz, Steven A.; Chan, Chris C.

    1994-05-01

    Results of an experimental program to assess the aerothermal ablation response of simulated radioisotope power supplies are presented. Full-scale general purpose heat source, graphite impact shell, and lightweight radioisotope heater unit test articles are all tested without nuclear fuel in simulated reentry environments. Convective stagnation heating, stagnation pressure, stagnation surface temperature, surface recession profile, and weight loss measurements are obtained for diffusion-limited and sublimation ablation conditions. The recession profile and weight loss measurements show an effect of surface features on the stagnation face. The surface features alter the local heating which in turn affects the local ablation.

  6. Recent strikes in South Africa’s platinum-group metal mines: effects upon world platinum-group metal supplies

    Science.gov (United States)

    Yager, Thomas R.; Soto-Viruet, Yadira; Barry, James J.

    2012-01-01

    The recent labor disputes over wages and working conditions that have affected South Africa’s three leading platinum-group metal (PGM) producers have affected an industry already plagued by market pressures and labor unrest and raised the specter of constraints in the world’s supply of these metals. Although low demand for these metals in 2011 and 2012 helped to offset production losses of recent years, and particularly those losses caused by the strikes in 2012, a prolonged resumption of strikes could cause severe shortages of iridium, platinum, rhodium, ruthenium, and, to a lesser extent, palladium.

  7. Nonlocal optical response in metallic nanostructures

    OpenAIRE

    Raza, Søren; Bozhevolnyi, Sergey I.; Wubs, Martijn; Mortensen, N. Asger

    2014-01-01

    This review provides a broad overview of the studies and effects of nonlocal response in metallic nanostructures. In particular, we thoroughly present the nonlocal hydrodynamic model and the recently introduced generalized nonlocal optical response (GNOR) model. The influence of nonlocal response on plasmonic excitations is studied in key metallic geometries, such as spheres and dimers, and we derive new consequences due to the GNOR model. Finally, we propose several trajectories for future w...

  8. Dynamic Supply Response Analysis of Pakistani Rice Growers

    Directory of Open Access Journals (Sweden)

    F.M.Shaikh

    2008-09-01

    Full Text Available Alternative specifications of model of supply response of Pakistani rice growers and their economic implications are considered in terms of the existences and nature of production lags, and the choice between expected price and gross returns as the preferred explanatory of producer‟s response to changing economic condition. The analysis indicates that there are lags which are due primarily to the difficulties and cost of rapid adjustment rather than to the time required to revise expectations. The statistical results were similar for the alternative specification of gross margins and prices as the economic decision available. However, the price elasticities derived using the gross margins specification were about a third of those using the prices specification. The gross margin specification yielded additional information in the form of yield and input cost elasticities.

  9. VBDO Responsible Supply Chain Benchmark 2012. A comparative investigation into CSR in the supply chain of 40 multinationals

    Energy Technology Data Exchange (ETDEWEB)

    Bres, C.; Cotterell, P.; Kaya, R.; Verbunt, S.

    2012-11-15

    This benchmark is a qualitative (partly quantitative), comparative investigation among 40 Dutch publicly listed companies, aiming to inform stakeholders on responsible supply chain management. These stakeholders are company executives, investors, academia, NGOs, government and society at large. Rather than concentrate on the nature of a company's activities, this benchmark focuses on the company's supply chain governance and management thereof. This makes it possible to compare, to a reasonable degree, the responsible supply chain policies of companies across different sectors.

  10. Responsiveness and flexibility in a Decentralized Supply Chain

    OpenAIRE

    Petersen, Kristian Rasmus; Bilberg, Arne; Hadar, Ronen

    2012-01-01

    Today’s supply chains are not capable of managing the instabilities that is the case in the market. Instead, there is a need to develop supply chains that are capable of adapting to changes. Through a case study of LEGO, the authors suggest a possible solution: a decentralized supply chain serving independent and self-sufficient local factories. The decentralized supply chain is provided with materials, parts and pre-assembled elements from local suppliers and supplies the local market in ret...

  11. Is the Money Responsible? : Financial institutions’ human rights responsibilities along a supply chain.

    OpenAIRE

    Wikström, Linnea

    2016-01-01

    Corporate Social Responsibility (CSR) is a topic of rising importance in the current human rights discussion. As multinational supply chains have a growing impact on people’ lives, both in more developed and developing countries the question of how to regulate the behaviour of the companies that engage in these supply chains becomes increasingly important. States have tried to do this through both national and international law, by introducing hard law regulations as well as voluntary framewo...

  12. Nonlocal optical response in metallic nanostructures.

    Science.gov (United States)

    Raza, Søren; Bozhevolnyi, Sergey I; Wubs, Martijn; Asger Mortensen, N

    2015-05-13

    This review provides a broad overview of the studies and effects of nonlocal response in metallic nanostructures. In particular, we thoroughly present the nonlocal hydrodynamic model and the recently introduced generalized nonlocal optical response (GNOR) model. The influence of nonlocal response on plasmonic excitations is studied in key metallic geometries, such as spheres and dimers, and we derive new consequences due to the GNOR model. Finally, we propose several trajectories for future work on nonlocal response, including experimental setups that may unveil further effects of nonlocal response.

  13. Nonlocal optical response in metallic nanostructures

    DEFF Research Database (Denmark)

    Raza, Søren; Bozhevolnyi, Sergey I.; Wubs, Martijn

    2015-01-01

    This review provides a broad overview of the studies and effects of nonlocal response in metallic nanostructures. In particular, we thoroughly present the nonlocal hydrodynamic model and the recently introduced generalized nonlocal optical response (GNOR) model. The influence of nonlocal response...... on plasmonic excitations is studied in key metallic geometries, such as spheres and dimers, and we derive new consequences due to the GNOR model. Finally, we propose several trajectories for future work on nonlocal response, including experimental setups that may unveil further effects of nonlocal response....

  14. Heavy oil supply economics and supply response to low oil prices

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, L. [Canadian Energy Research Inst., Calgary, AB (Canada)

    1999-04-01

    The dynamics of the heavy oil industry are examined, including prices, market demand, supply and supply costs. Price assumptions are provided for the reference case oil price (west Texas intermediate at Cushing). Supply cost methodology is explained. Capital and operating costs for various heavy oil and synthetic sources are derived from modeling results. The range of supply costs for heavy oil and bitumen from various sources, supply costs in terms of reference case market values and in terms of 1995-1996 average market values for Bow River crude, are derived. The CERI long term supply forecast model is explained. Western Canada upstream oil and gas cash flow and capital expenditures, eastern Canada exploration and expenditures by hydrocarbon type, and Canadian heavy oil and bitumen production based on reference case prices are estimated. Based on these projections the outlook for heavy oil at reference case prices for better than average quality resources is judged to be economic. Lower quality resources will require technology gains for successful commercialization. SAGD is a likely candidate in this respect. Again based on reference prices, production is forecast to decline by 100 Kb/d over the next five years. Diluent supply is considered to be adequate throughout the forecast period. As far as thermal bitumen is concerned, the growth could, in fact, exceed the projection, but if so, more upgrading will be required. 11 figs.

  15. Metal ions potentiate microglia responsiveness to endotoxin.

    Science.gov (United States)

    Rachmawati, Dessy; Peferoen, Laura A N; Vogel, Daphne Y S; Alsalem, Inás W A; Amor, Sandra; Bontkes, Hetty J; von Blomberg, B Mary E; Scheper, Rik J; van Hoogstraten, Ingrid M W

    2016-02-15

    Oral metal exposure has been associated with diverse adverse reactions, including neurotoxicity. We showed previously that dentally applied metals activate dendritic cells (MoDC) via TLR4 (Ni, Co, Pd) and TLR3 (Au). It is still unknown whether the low levels of dental metals reaching the brain can trigger local innate cells or prime them to become more responsive. Here we tested whether dentally applied metals (Cr, Fe, Co, Ni, Cu, Zn, Au, Hg) activate primary human microglia in vitro and, as a model, monocytic THP-1-cells, in high non-toxic as well as near-physiological concentrations. In addition the effects of 'near-physiological' metal exposure on endotoxin (LPS) responsiveness of these cells were evaluated. IL-8 and IL-6 production after 24h was used as read out. In high, non-toxic concentrations all transition metals except Cr induced IL-8 and IL-6 production in microglia, with Ni and Co providing the strongest stimulation. When using near-physiological doses (up to 10× the normal plasma concentration), only Zn and Cu induced significant IL-8 production. Of note, the latter metals also markedly potentiated LPS responsiveness of microglia and THP-1 cells. In conclusion, transition metals activate microglia similar to MoDCs. In near-physiological concentrations Zn and Cu are the most effective mediators of innate immune activation. A clear synergism between innate responses to Zn/Cu and LPS was observed, shedding new light on the possible relation between oral metal exposure and neurotoxicity.

  16. Performance Determinants for Responsible Supply Chain Management in the European Emerging Countries

    OpenAIRE

    Camelia Chirilă; Andreea Gangone; Mihaela Asandei; Mariana Cristina Ganescu

    2013-01-01

    Starting from the premise that there are numerous institutional and national factors influencing the performance of responsible supply chain management, the present article seeks to measure and quantify performance of the European emerging states by creating an index of performance of responsible supply chain management and to identify the factors that influence responsible supply chain management. The acquisition of this index was based on our own measurement methodology, starting from two c...

  17. Critical thinking: assessing the risks to the future security of supply of critical metals

    Science.gov (United States)

    Gunn, Gus

    2015-04-01

    Increasing world population, the spread of prosperity across the globe and the demands of new technologies have led to a revival of concerns about the availability of raw materials needed by society. Despite scare stories about resource depletion, physical exhaustion of minerals is considered to be unlikely. However, we do need to know which materials might be of concern so that we can develop strategies to secure adequate supplies and to mitigate the effects of supply disruption. This requirement has led to renewed interest in criticality, a term that is generally used to refer to metals and minerals of high economic importance that have a relatively high likelihood of supply disruption. The European Union (EU) developed a quantitative methodology for the assessment of criticality which led to the definition of 14 raw materials as critical to the EU economy (EC, 2010). This has succeeded in raising awareness of potential supply issues and in helping to prioritise requirements for new policies and supporting research. The EU has recently assessed a larger number of candidate materials of which 20 are now identified as critical to the EU (EC, 2014). These include metals such as indium, mostly used in flat-screen displays, antimony for flame retardants and cobalt for rechargeable batteries, alloys and a host of other products. Although there is no consensus on the methodology for criticality assessments and broad analyses at this scale are inevitably imperfect, they can, nevertheless, provide early warning of supply problems. However, in order to develop more rigorous and dynamic assessments of future availability detailed analysis of the whole life-cycle of individual metals to identify specific problems and develop appropriate solutions is required. New policies, such as the Raw Materials Initiative (2008) and the European Innovation Partnership on Raw Materials (2013), have been developed by the European Commission (EC) and are aimed at securing sustainable

  18. A Dynamic Stackelberg Game of Supply Chain for a Corporate Social Responsibility

    Directory of Open Access Journals (Sweden)

    Massimiliano Ferrara

    2017-01-01

    Full Text Available In this paper, we establish a dynamic game to allocate CSR (Corporate Social Responsibility to the members of a supply chain. We propose a model of a supply chain in a decentralized state which includes a supplier and a manufacturer. For analyzing supply chain performance in decentralized state and the relationships between the members of the supply chain, we formulate a model that crosses through multiperiods with the help of a dynamic discrete Stackelberg game which is made under two different information structures. We obtain an equilibrium point at which both the profits of members and the level of CSR taken up by supply chains are maximized.

  19. Stochastic optimization of mine production scheduling with uncertain ore/metal/waste supply

    Institute of Scientific and Technical Information of China (English)

    Leite Andre; Dimitrakopoulos Roussos

    2014-01-01

    Optimization of long-term mine production scheduling in open pit mines deals with the management of cash flows, typically in the order of hundreds of millions of dollars. Conventional mine scheduling utilizes optimization methods that are not capable of accounting for inherent technical uncertainties such as uncertainty in the expected ore/metal supply from the underground, acknowledged to be the most critical factor. To integrate ore/metal uncertainty into the optimization of mine production scheduling a stochastic integer programming (SIP) formulation is tested at a copper deposit. The stochastic solution maximizes the economic value of a project and minimizes deviations from production targets in the pres-ence of ore/metal uncertainty. Unlike the conventional approach, the SIP model accounts and manages risk in ore supply, leading to a mine production schedule with a 29%higher net present value than the schedule obtained from the conventional, industry-standard optimization approach, thus contributing to improving the management and sustainable utilization of mineral resources.

  20. Alfalfa response to irrigation from limited water supplies

    Science.gov (United States)

    A five-year field study (2007-2011) of irrigated alfalfa production with a limited water supply was conducted in southwest Kansas with two years of above-average precipitation, one year of average precipitation, and two years of below-average precipitation. The irrigation treatments were designed to...

  1. Metal accumulation in tobacco expressing Arabidopsis halleri metal hyperaccumulation gene depends on external supply.

    Science.gov (United States)

    Barabasz, Anna; Krämer, Ute; Hanikenne, Marc; Rudzka, Justyna; Antosiewicz, Danuta Maria

    2010-06-01

    Engineering enhanced transport of zinc to the aerial parts of plants is a major goal in bio-fortification. In Arabidopsis halleri, high constitutive expression of the AhHMA4 gene encoding a metal pump of the P(1B)-ATPase family is necessary for both Zn hyperaccumulation and the full extent of Zn and Cd hypertolerance that are characteristic of this species. In this study, an AhHMA4 cDNA was introduced into N. tabacum var. Xanthi for expression under the control of its endogenous A. halleri promoter known to confer high and cell-type specific expression levels in both A. halleri and the non-hyperaccumulator A. thaliana. The transgene was expressed at similar levels in both roots and shoots upon long-term exposure to low Zn, control, and increased Zn concentrations. A down-regulation of AhHMA4 transcript levels was detected with 10 muM Zn resupply to tobacco plants cultivated in low Zn concentrations. In general, a transcriptional regulation of AhHMA4 in tobacco contrasted with the constitutively high expression previously observed in A. halleri. Differences in root/shoot partitioning of Zn and Cd between transgenic lines and the wild type were strongly dependent on metal concentrations in the hydroponic medium. Under low Zn conditions, an increased Zn accumulation in the upper leaves in the AhHMA4-expressing lines was detected. Moreover, transgenic plants exposed to cadmium accumulated less metal than the wild type. Both modifications of zinc and cadmium accumulation are noteworthy outcomes from the biofortification perspective and healthy food production. Expression of AhHMA4 may be useful in crops grown on soils poor in Zn.

  2. Issues and Challenges in Self-Sustaining Response Supply Chains

    Science.gov (United States)

    2013-09-28

    nodes supply items such as water, food, or fuel. Examples of the suppliers can be found in the private, military, and public sectors. The franchises ...Santa Monica, CA: RAND. Retrieved from www.rand.org/pubs/monographs/2005/RAND_MG342. pdf Plambeck, E., & Denend, L. (2010, September/October). The...13-026. http://www.acquisitionresearch.net/files/FY2013/NPS-LM-13-026. pdf Robeson, J. F., & Copacino, W. C. (Eds.). (1994). The logistics handbook

  3. Establishment of Grain Farmers' Supply Response Model and Empirical Analysis under Minimum Grain Purchase Price Policy

    OpenAIRE

    Zhang, Shuang

    2012-01-01

    Based on farmers' supply behavior theory and price expectations theory, this paper establishes grain farmers' supply response model of two major grain varieties (early indica rice and mixed wheat) in the major producing areas, to test whether the minimum grain purchase price policy can have price-oriented effect on grain production and supply in the major producing areas. Empirical analysis shows that the minimum purchase price published annually by the government has significant positive imp...

  4. Nitrogen Under- and Over-supply Induces Distinct Protein Responses in Maize Xylem Sap

    Institute of Scientific and Technical Information of China (English)

    Chengsong Liao; Renyi Liu; Fusuo Zhang; Chunjian Li; Xuexian Li

    2012-01-01

    Xylem sap primarily transports water and mineral nutrients such as nitrogen (N) from roots to shoots in vascular plants.However,it remains largely unknown how nitrogenous compounds,especially proteins in xylem sap,respond to N under- or over-supply.We found that reducing N supply increased amino-N percentage of total N in maize (Zea mays L.) xylem sap.Proteomic analysis showed that 23 proteins in the xylem sap of maize plants,including 12 newly identified ones,differentially accumulated in response to various N supplies.Fifteen of these 23 proteins were primarily involved in general abiotic or biotic stress responses,whereas the other five proteins appeared to respond largely to N under- or over-supply,suggesting distinct protein responses in maize xylem upon N under- and over-supply.Furthermore,one putative xylanase inhibitor and two putative O-glycosyl hydrolases had preferential gene expression in shoots.

  5. Measuring Labour Supply Responses to Tax Changes by Use of Exogenous Tax Reforms

    DEFF Research Database (Denmark)

    Graversen, Ebbe Krogh

    1996-01-01

    This paper estimates average labour supply responses to tax changes for women in Denmark using the tax reform in 1987 as a natural experiment to identify the responsiveness to tax changes. Both changes in the participation rate and in worki ng hous are considered. A nonparametric difference......-in-difference (DID) estimator and a suitable modified parametric DID estimator are used to estimate the labour supply responses and calculate labour supply elasticities with respect to marg inal tax rates and wage rates net of taxes. Finally, we simulate the effect of the fully implemented Danish 1994/1998 tax...

  6. Assessing the marketing potential of communicating corporate social responsibility of a supply chain: method and application

    NARCIS (Netherlands)

    Verhees, F.J.H.M.; Kuipers, A.; Meulenberg, M.T.G.

    2006-01-01

    Abstract This article provides a method to assess the marketing potential of communicating corporate social responsibility of (agricultural) supply chains. The willingness of small firms in agricultural supply chains to make available information about certain dimensions of CSR is measured and combi

  7. Labor supply response to personal income taxation in Mexico

    Directory of Open Access Journals (Sweden)

    Jorge N. Valero-Gil

    2006-09-01

    Full Text Available This paper examines the effect of marginal income tax rates on labor supply in Mexico using a modified version of Rosen´s (1976 personal income taxation model. The study analyzes how salaried workers of the formal sector react to changes in the marginal income tax rate. Special attention is given to the sample, in order to control the problem of the high level of tax evasion in Mexico in our estimation. We find evidence that hours of work diminish when marginal income tax rates increase.

  8. Strategic guide to natural disaster planning, preparedness, response and recovery for Naval Supply Center, Oakland, California

    OpenAIRE

    Kibler, Christopher T.; Kerber, James L.

    1990-01-01

    Approved for public release; distribution is unlimited. The Specific goal of this thesis is to provide a strategic guide which can be used as a basis by Naval Supply Center (NSC), Oakland, California to formulate a natural disaster planning, preparedness, response and recovery program. The objective of such a aprogram is to reduce the amount of damage caused by a natural disaster, enable effective response to a disaster and facilitate recovery. The plan must be consistent with the supply c...

  9. Establishment of Grain Farmers’ Supply Response Model and Empirical Analysis under Minimum Grain Purchase Price Policy

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Based on farmers’ supply behavior theory and price expectations theory,this paper establishes grain farmers’ supply response model of two major grain varieties (early indica rice and mixed wheat) in the major producing areas,to test whether the minimum grain purchase price policy can have price-oriented effect on grain production and supply in the major producing areas. Empirical analysis shows that the minimum purchase price published annually by the government has significant positive impact on farmers’ grain supply in the major grain producing areas. In recent years,China steadily raises the level of minimum grain purchase price,which has played an important role in effectively protecting grain farmers’ interests,mobilizing the enthusiasm of farmers’ grain production,and ensuring the market supply of key grain varieties.

  10. Elderly Immigrants' Labor Supply Response to Supplemental Security Income

    Science.gov (United States)

    Kaushal, Neeraj

    2010-01-01

    This paper examined how the 1996 Personal Responsibility and Work Opportunity Reconciliation Act, which banned Supplemental Security Income (SSI) for the majority of elderly immigrants, affected their employment, retirement, and family incomes. The policy was found to be associated with a 3.5 percentage point (9.5 percent) increase in the…

  11. Optimal copper supply is required for normal plant iron deficiency responses.

    Science.gov (United States)

    Waters, Brian M; Armbrust, Laura C

    2013-01-01

    Iron (Fe) and copper (Cu) homeostasis are tightly linked across biology. Understanding crosstalk between Fe and Cu nutrition could lead to strategies for improved growth on soils with low or excess metals, with implications for agriculture and phytoremediation. Here, we show that Cu and Fe nutrition interact to increase or decrease Fe and/or Cu accumulation in leaves and Fe uptake processes. Leaf Cu concentration increased under low Fe supply, while high Cu lowered leaf Fe concentration. Ferric reductase activity, an indicator of Fe demand, was inhibited at insufficient or high Cu supply. Surprisingly, plants grown without Fe were more susceptible to Cu toxicity.

  12. Enhanced rectifying response from metal-insulator-insulator-metal junctions

    Science.gov (United States)

    Maraghechi, P.; Foroughi-Abari, A.; Cadien, K.; Elezzabi, A. Y.

    2011-12-01

    We present on a metal-insulator-insulator-metal quantum electronic tunneling devices suitable for high speed rectifiers. Through the introduction of double oxide layer between similar metallic electrodes, a cascaded potential barrier is formed which alters the electron tunneling mechanism at forward versus the reverse bias. The cascaded potential barrier engineering manifests itself in both a highly nonlinear and asymmetric I-V junction characteristic. It is envisioned that high speed rectifiers and mixers having extraordinary nonlinearity can be realized through the incorporation of the cascaded potential barrier architecture and dissimilar metallic electrodes.

  13. Microbial nitrogen metabolism: response to warming and resource supply

    Science.gov (United States)

    Buckeridge, K. M.; Min, K.; Lehmeier, C.; Ballantyne, F.; Billings, S. A.

    2013-12-01

    Ecosystem nitrogen (N) dynamics are dependent on microbial metabolic responses to a changing climate. Most studies that investigate soil microbial N dynamics in response to temperature employ measurements reflective of many interacting and confounding phenomena, as altering soil temperature can simultaneously alter moisture regime, substrate availability, and competitive dynamics between microbial populations. As a result, it is difficult to discern how temperature alone can alter patterns of microbial N metabolism using whole soils. Without that knowledge, it is impossible to parse temperature effects on soil N fluxes from other drivers. We address this issue by exploring the sensitivity of microbial partitioning of N between assimilation (growing biomass) and dissimilation (releasing N to the environment) in response to changes in temperature and quality (C:N ratio) of substrate, using a chemostat approach in which a microbial population is maintained at steady state. We perform our experiments using a Gram-negative bacterium (Pseudomonas fluorescens), ubiquitous in soils and dependent on organic compounds to satisfy its resource demand. Individual chemostat runs, all conducted at similar microbial growth rates, generate data describing microbial biomass N, solution N pools and microbial biomass and solution d15N. With these data we can calculate d15N enrichment (d15N microbial biomass - d15N nutrient solution) a proxy for microbial N partitioning. From a recently published model of microbial biomass d15N drivers, fractionation of N occurs with both uptake and excretion of NH3+ so that microbes with a net dissimilation become 15N enriched relative to their source. Because a related study has demonstrated increased microbial C demand with temperature, we predict that in a warming environment microorganisms will become relatively C limited. Accordingly, we hypothesize that warming will enhance microbial dissimilation, and that this N release will be exacerbated as

  14. Extending producer responsibility up and down the supply chain, challenges and limitation.

    Science.gov (United States)

    Scheijgrond, Jan-Willem

    2011-09-01

    Producers are given increasing responsibility by governmental organizations to address environmental and human rights issues along the supply chain. While producers indeed have a responsibility to address these issues, governments' expectations of producers are often too high and in some cases unrealistic. Ruggie's framework to protect, respect and remedy provides a useful tool to determine the responsibilities of government and business in relation to human rights. If it is applied to product-related environmental aspects, which affect human rights, it offers a good tool to evaluate whether producer responsibility has been implemented in a way to institutionally align business and governments. An analysis of extended producer responsibility up and down the supply chain on the basis of waste electrical and electronic equipment (WEEE) legislation, REACH legislation and conflict minerals shows that such alignment has not been achieved.

  15. Optimizing complex supply chains. Applications in the petroleum, shipping and metal industries

    Energy Technology Data Exchange (ETDEWEB)

    Ulstein, Nina Linn

    2005-07-01

    products to plants. The model gives a description of Elkem's supply chain, and gives planners the possibility to explore alternative decisions and study the effects in economic and physical terms. The main contribution from this paper consists of presenting a successful application of an optimization tool, used in a critical decision making process for the company. The paper also offers useful insight into the process of developing and applying the model. The paper is co-authored by Marielle Christiansen, Roar Groenhaug, Nick Magnussen and Marius M. Solomon, and has been submitted to Interfaces. Paper 4: Supply Chain Design in the Metals Production Industry under Uncertainty in Future Prices and Demands This paper describes a stochastic extension to the planning Mol described in Paper 3. The two-stage stochastic model includes alternative scenarios for future developments in market prices and demand. This help Elkem identify robust strategies with regard to future changes in the market. The stochastic model is a large scale MIP problem and a specialised solution algorithm is proposed for solving practical problem instances. The algorithm decomposes the problem per scenario and applies global branching on first-stage variables to re-establish non-anticipativity. The main contribution from this paper is to model and solve a real-world stochastic supply chain design problem. This includes presenting a solution algorithm which enables the solution of practical problem instances. The paper has been submitted to the European Journal of Operational Research. (Author)

  16. A Two-Stage Approach for Medical Supplies Intermodal Transportation in Large-Scale Disaster Responses

    Directory of Open Access Journals (Sweden)

    Junhu Ruan

    2014-10-01

    Full Text Available We present a two-stage approach for the “helicopters and vehicles” intermodal transportation of medical supplies in large-scale disaster responses. In the first stage, a fuzzy-based method and its heuristic algorithm are developed to select the locations of temporary distribution centers (TDCs and assign medial aid points (MAPs to each TDC. In the second stage, an integer-programming model is developed to determine the delivery routes. Numerical experiments verified the effectiveness of the approach, and observed several findings: (i More TDCs often increase the efficiency and utility of medical supplies; (ii It is not definitely true that vehicles should load more and more medical supplies in emergency responses; (iii The more contrasting the traveling speeds of helicopters and vehicles are, the more advantageous the intermodal transportation is.

  17. Metal-enclosed air-insulated switchgear for the use in railway power supply systems; Metallgekapselte, luftisolierte Bahnstromschaltanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Loenard, D.; Northe, J. [Balfour Beatty Rail GmbH Power Systems, Offenbach (Germany); Blecher, U. [Ritter Starkstromtechnik GmbH und Co. KG, Geschaeftsbereich Anlagen und Werk fuer Schaltanlagen, Olfen (Germany)

    2004-07-01

    The medium-voltage switchgear of type TracFeed TAC has been designed for the use in standard, booster (1AC) and autotransformer (2AC) 25 kV 50/60 Hz railway power supply systems. This railway switchgear is of metal-enclosed air-insulated design and has been type tested according to EN 62271-200. It meets the special requirements described in the paper entitled ''Requirements on medium-voltage switchgear for railway power supply'' published in No. 10/2003. (orig.)

  18. Responsiveness through buyer-focused cells : Exploring a new supply strategy

    NARCIS (Netherlands)

    van Donk, D.P.; van der Vaart, T.

    2007-01-01

    Purpose - The concept of buyer focus has recently been introduced as a new supply chain strategy, although the design and operation of buyer-focused cells have hardly been investigated. The purpose of this paper is to investigate how buyer-focused cells realise responsiveness. Design/methodology/app

  19. Responsiveness through buyer-focused cells : Exploring a new supply strategy

    NARCIS (Netherlands)

    van Donk, D.P.; van der Vaart, T.

    2007-01-01

    Purpose - The concept of buyer focus has recently been introduced as a new supply chain strategy, although the design and operation of buyer-focused cells have hardly been investigated. The purpose of this paper is to investigate how buyer-focused cells realise responsiveness.

  20. The paradigm of consumer-driven and responsive supply chains: An integrated project approach

    NARCIS (Netherlands)

    Zimmermann, K.L.; Lans, van der I.A.

    2009-01-01

    This paper describes an integrated project approach that forms the basis of the studies on consumer-driven innovative and responsive supply chains in ISAFRUIT Pillar 1. This integrated approach leads to a wide range of indepth results on trends, preferences, and innovativeness of the European consum

  1. Differential responses of sweetpotato peroxidases to heavy metals.

    Science.gov (United States)

    Kim, Yun-Hee; Lee, Haeng-Soon; Kwak, Sang-Soo

    2010-09-01

    Oxidative stress is one of the major causes of damage in plants exposed to different types of environmental stress, including heavy metals. Accumulation of heavy metals in plants can disrupt many cellular functions and plant growth. To assess the contribution of oxidative stress to heavy metal toxicity in plants, young sweetpotato plants (Ipomoea batatas) were treated with increasing concentrations of Cd, Cu and Zn, and grown in half Murashige and Skoog nutrient solution culture. Plant growth was significantly inhibited and internal metal content was increased in a dose-dependent manner for each metal. The generation of H(2)O(2) in leaves and fibrous roots correlated positively with metal dose. The specific activity of peroxidases (PODs) in fibrous roots was markedly enhanced by metal treatment, whereas in leaves, activity was low and only slightly affected by metal treatment. Analysis of 13 POD genes revealed differential expression of PODs in response to heavy metals. Several genes for acidic PODs (swpa2, swpa3 and swpa4) and basic PODs (swpb1, swpb3 and swpab4) were strongly expressed under all metal treatment conditions in leaves or fibrous roots. The expression of swpa1 was increased in leaves and fibrous roots by Cd and Cu treatment, whereas swpb5 expression was reduced by all metals in fibrous roots. These results indicate that increased H(2)O(2) levels in response to heavy metal stress are closely linked to an improved antioxidant defense capability mediated by POD.

  2. Competitive platinum-group-metal (PGM) supply from the Eastern Limb, Bushveld Complex: Geological, mining and mineral economic aspects

    CSIR Research Space (South Africa)

    McGill, JE

    2011-08-01

    Full Text Available -GROUP-METAL (PGM) SUPPLY FROM THE EASTERN LIMB, BUSHVELD COMPLEX: GEOLOGICAL, MINING, AND MINERAL ECONOMIC ASPECTS Dr. Jeannette E. McGill & Prof. Murray W. Hitzman ACKNOWLEDGEMENTS ? COUNCIL FOR SCIENTIFIC AND INDUSTRIAL RESEARCH (CSIR) ? Centre for Mining... Innovation ? Office of Graduate Studies, Fogarty Endowment ? Mr. VISHNU PILLAY (EXECUTIVE HEAD: JV?S ? Anglo Platinum) ? ACADEMIC ADVISORS Prof. Murray Hitzman (Economic Geology); Dr. Hugh Miller (Mining Engineering); Prof. Rodderick Eggert (Mineral...

  3. Markets during world oil supply crises: an analysis of industry, consumer, and governmental response

    Energy Technology Data Exchange (ETDEWEB)

    Erfle, Stephen; Pound, John; Kalt, Joseph

    1981-04-01

    An analysis of the response of American markets to supply crises in world oil markets is presented. It addresses four main issues: the efficiency of the operation of American oil markets during oil supply crises; the problems of both economic efficiency and social equity which arise during the American adaptation process; the propriety of the Federal government's past policy responses to these problems; and the relationship between perceptions of the problems caused by world oil crises and the real economic natures of these problems. Specifically, Chapter 1 presents a theoretical discussion of the effects of a world supply disruption on the price level and supply availability of the world market oil to any consuming country including the US Chapter 2 provides a theoretical and empirical analysis of the efficiency of the adaptations of US oil product markets to higher world oil prices. Chapter 3 examines the responses of various groups of US oil firms to the alterations observed in world markets, while Chapter 4 presents a theoretical explanation for the price-lagging behavior exhibited by firms in the US oil industry. Chapter 5 addresses the nature of both real and imagined oil market problems in the US during periods of world oil market transition. (MCW)

  4. Assessment of heavy metals in the industrial effluents, tube-wells and municipal supplied water of Dehradun, India.

    Science.gov (United States)

    Kulshrestha, Shail; Awasthi, Alok; Dabral, S K

    2013-07-01

    The bio-geochemical cycles of metals involve the lands, rivers, oceans and the atmosphere. Although a large number of metals are introduced to the water bodies during their mining and extraction processes and geochemical weathering of rocks, but the role of domestic and industrial wastes is predominant and of much concern. Increased industrial activities has increased the incidence of percolation of toxic metal ions to the soil and water bodies and presently their presence in ecosystem, have reached to an alarming level that environmentalists are finding it difficult to enforce control measures. Human activities and large number of small and big industrial units are increasingly discharging deleterious metals present in the effluents and wastes, to the environment and aquatic systems and have contaminated heavily even the ground water. The toxic metals have a great tendency of bioaccumulation through which they enter the food chain system and ultimately affect adversely the life on this planet Earth in various ways. Further, due to contamination of irrigation system by the harmful Chemicals and toxic metals, the farm products, vegetables, fruits, potable water and even milk is not spared. This paper describes the assessment of the heavy metal concentration in various industrial effluents of the surrounding area. Various physico-chemical characteristics of the effluents collected from various sites are also reported. To assess the status of ground water quality, water samples from four tube wells of different localities of the area and four drinking water samples supplied by Municipal Distribution System were also analyzed.

  5. MARKET SUPPLY RESPONSE AND DEMAND FOR LOCAL RICE IN NIGERIA: IMPLICATIONS FOR SELF-SUFFICIENCY POLICY

    Directory of Open Access Journals (Sweden)

    M RAHJI

    2009-03-01

    Full Text Available This study examined the supply response and demand for local rice in Nigeria between 1960 and 2004. A system of equations using secondary data was estimated by OLS and 2SLS techniques. Area planted with local rice is mainly affected by expected price of output, agriculture wage rate and by the partial adjustment coefficient. The short-run response elasticity is 0.077. The implied long-run response elasticity is 1.578. The partial adjustment measure is 0.049. This, points to the difficulty of supply response to changing economic conditions. The price elasticity of demand obtained is 0.841. The demand for local rice is thus price inelastic. Rice income elasticity is 0.3378. It is also inelastic. The ban on rice importation in Nigeria could be said to be a step in the right direction. This policy should be continued and policed. However, price, output and non-price incentives that can exert significant influence on rice supply response and demand are required if the self-sufficiency goal is to be achieved.

  6. MicroRNAs as regulators in plant metal toxicity response

    Directory of Open Access Journals (Sweden)

    Ana Belen Mendoza-Soto

    2012-05-01

    Full Text Available Metal toxicity is a major stress affecting crop production. This includes metals that are essential for plants (copper, iron, zinc, manganese, and non-essential metals (cadmium, aluminum, cobalt, mercury. A primary common effect of high concentrations of metals such as aluminum, cooper, cadmium or mercury, is root growth inhibition. Metal toxicity triggers the accumulation of reactive oxygen species leading to damage of lipids, proteins and DNA. The plants response to metal toxicity involves several biological processes that require fine and precise regulation at transcriptional and post-transcriptional levels. MicroRNAs (miRNAs are 21 nucleotides non-coding RNAs that regulate gene expression at the post-transcriptional level. A miRNA, incorporated into a RNA induced silencing complex, promotes cleavage of its target mRNA that is recognized by an almost perfect base complementarity. In plants miRNA regulation has been involved in development and also in biotic and abiotic stress responses. We review novel advances in identifying miRNAs related to metal toxicity responses and their potential role according to their targets. Most of the targets for plant metal-responsive miRNAs are transcription factors. Information about metal-responsive miRNAs in different plants points to important regulatory roles of miR319, miR390, miR393 and miR398. The target of miR319 is the TCP transcription factor, implicated in growth control. MiR390 exerts its action through the biogenesis of trans-acting small interference RNAs that, in turn, regulate auxin responsive factors. MiR393 targets the auxin receptors TIR1/AFBs and a bHLH transcription factor. Increasing evidence points to the crucial role of miR398 and its targets Cu/Zn superoxide dismutases in the control of the oxidative stress generated after high metal copper or iron exposure.

  7. Growth response and heavy metals tolerance of Axonopus affinis ...

    African Journals Online (AJOL)

    Jane

    2010-12-20

    Dec 20, 2010 ... assayed heavy metals, suggesting a synergistic effect between this species and the rhizobacterium in response ... soils, mainly in regions of copper and gold with great ..... enhance plant biomass production in mine tailings at.

  8. Response of alternate bar topography to variation in sediment supply in gravel-bedded rivers

    Science.gov (United States)

    Venditti, J. G.; Minear, J. T.; Nelson, P. A.; Wooster, J.; Dietrich, W. E.

    2006-12-01

    the pool, followed by a progressive lateral mobilization and downstream transport of the bar surface. Interestingly, the volume of gravel material needed to reestablish the bars was roughly equivalent to the material removed during bar washout. Our observations seem to contradict those from previous experiments, which suggest that alternate bars respond to sediment supply reductions by deepening in the pools and emergence of the bar tops. However, the prior work was designed to examine steep stream conditions where Dmax/d was near unity. Thus, the response of alternate bar topography to variation in sediment supply may be modulated by relative roughness. Topographic dampening has not previously been observed experimentally, but it is consistent with observations of river channels downstream of many dams. The results suggest that sediment supply may play an important role in bar development and stability in river channels. Restoration strategies that seek to reinvigorate channel bars may require restoration of the pre-impact grade and sediment supply. The issue of how bars respond to linked changes in sediment supply and water flow needs to be addressed.

  9. A carbohydrate supply and demand model of vegetative growth: response to temperature and light.

    Science.gov (United States)

    Gent, Martin P N; Seginer, Ido

    2012-07-01

    Photosynthesis is the limiting factor in crop growth models, but metabolism may also limit growth. We hypothesize that, over a wide range of temperature, growth is the minimum of the supply of carbohydrate from photosynthesis, and the demand of carbohydrate to synthesize new tissue. Biosynthetic demand limits growth at cool temperatures and increases exponentially with temperature. Photosynthesis limits growth at warm temperatures and decreases with temperature. Observations of tomato seedlings were used to calibrate a model based on this hypothesis. Model predictions were tested with published data for growth and carbohydrate content of sunflower and wheat. The model qualitatively fitted the response of growth of tomato and sunflower to both cool and warm temperatures. The transition between demand and supply limitation occurred at warmer temperatures under higher light and faster photosynthesis. Modifications were required to predict the observed non-structural carbohydrate (NSC). Some NSC was observed at warm temperatures, where demand should exceed supply. It was defined as a required reserve. Less NSC was found at cool temperatures than predicted from the difference between supply and demand. This was explained for tomato and sunflower, by feedback inhibition of NSC on photosynthesis. This inhibition was much less in winter wheat.

  10. Major Crop Species Show Differential Balance between Root Morphological and Physiological Responses to Variable Phosphorus Supply

    Science.gov (United States)

    Lyu, Yang; Tang, Hongliang; Li, Haigang; Zhang, Fusuo; Rengel, Zed; Whalley, William R.; Shen, Jianbo

    2016-01-01

    The relationship between root morphological and physiological responses to variable P supply in different plant species is poorly understood. We compared root morphological and physiological responses to P supply in seven crop species (Zea mays, Triticum aestivum, Brassica napus, Lupinus albus, Glycine max, Vicia faba, Cicer arietinum) treated with or without 100 mg P kg-1 in two soils (acidic and calcareous). Phosphorus deficiency decreased root length more in fibrous root species (Zea mays, Triticum aestivum, Brassica napus) than legumes. Zea mays and Triticum aestivum had higher root/shoot biomass ratio and Brassica napus had higher specific root length compared to legumes, whereas legumes (except soybean) had higher carboxylate exudation than fibrous root species. Lupinus albus exhibited the highest P-acquisition efficiency due to high exudation of carboxylates and acid phosphatases. Lupinus albus and Cicer arietinum depended mostly on root exudation (i.e., physiological response) to enhance P acquisition, whereas Zea mays, Triticum aestivum and Brassica napus had higher root morphology dependence, with Glycine max and Vicia faba in between. Principal component analysis using six morphological and six physiological responses identified root size and diameter as the most important morphological traits, whereas important physiological responses included carboxylate exudation, and P-acquisition and P-utilization efficiency followed by rhizosphere soil pH and acid phosphatase activity. In conclusion, plant species can be grouped on the basis of their response to soil P being primarily via root architectural or exudation plasticity, suggesting a potential benefit of crop-specific root-trait-based management to cope with variable soil P supply in sustainable grain production. PMID:28066491

  11. Full Hydrodynamic Model of Nonlinear Electromagnetic Response in Metallic Metamaterials

    CERN Document Server

    Fang, Ming; Sha, Wei E I; Xiong, Xiaoyan Y Z; Wu, Xianliang

    2016-01-01

    Applications of metallic metamaterials have generated significant interest in recent years. Electromagnetic behavior of metamaterials in the optical range is usually characterized by a local-linear response. In this article, we develop a finite-difference time-domain (FDTD) solution of the hydrodynamic model that describes a free electron gas in metals. Extending beyond the local-linear response, the hydrodynamic model enables numerical investigation of nonlocal and nonlinear interactions between electromagnetic waves and metallic metamaterials. By explicitly imposing the current continuity constraint, the proposed model is solved in a self-consistent manner. Charge, energy and angular momentum conservation laws of high-order harmonic generation have been demonstrated for the first time by the Maxwell-hydrodynamic FDTD model. The model yields nonlinear optical responses for complex metallic metamaterials irradiated by a variety of waveforms. Consequently, the multiphysics model opens up unique opportunities f...

  12. A QUANTITATIVE ANALYSIS OF SUPPLY RESPONSE IN THE NAMIBIAN MUTTON INDUSTRY

    Directory of Open Access Journals (Sweden)

    D.N. Van Wyk

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: Agricultural activities in Namibia contribute 5.5% of Namibia’s GDP, while 70% of the population relies on agriculture for employment and day-to-day living. The purpose of this study is to investigate the relationships between the various price and non-price factors contributing to the supply dynamics within the mutton industry in Namibia. The autoregressive distributed lag approach to co-integration was used to determine the longrun and short-run supply response elasticities between economic and climatology factors on time-series data.
    Supply shifters showed significant short-run and long-run elasticities with regard to the mutton produced. Results also revealed that the system takes nearly two months to recover to the long-run supply equilibrium, should any disturbances occur within the supply system.

    AFRIKAANSE OPSOMMING: Landbou-aktiwiteite in Namibië dra 5.5% by tot die nasionale Bruto Binnelandse Produk, in ’n land waar meer as 70% van die bevolking afhanklik is van landbou om ’n bestaan te kan maak. Die doel van hierdie studie is om die verwantskappe te ondersoek tussen verskeie prys- en nie-prys-faktore wat bydra tot die aanboddinamika van die skaapvleisbedryf. ’n Outoregressie verspreide sloering benadering tot ko-integrasie is gebruik om die langtermyn en korttermyn elastisitiete tussen ekonomie- en klimaatfaktore vir skaapvleisaanbod te bepaal.
    Resultate het gewys dat aanbodfaktore betekenisvolle kort- en langtermyn elastisiteite toon. Resultate het ook getoon dat die sisteem twee maande neem om te herstel na die langtermyn aanbodekwilibruim, sou daar enige drastiese veranderings gebeur in die stelsel.

  13. Circular Economy: Questions for Responsible Minerals, Additive Manufacturing and Recycling of Metals

    Directory of Open Access Journals (Sweden)

    Damien Giurco

    2014-05-01

    Full Text Available The concept of the circular economy proposes new patterns of production, consumption and use, based on circular flows of resources. Under a scenario where there is a global shift towards the circular economy, this paper discusses the advent of two parallel and yet-to-be-connected trends for Australia, namely: (i responsible minerals supply chains and (ii additive manufacturing, also known as 3D production systems. Acknowledging the current context for waste management, the paper explores future interlinked questions which arise in the circular economy for responsible supply chains, additive manufacturing, and metals recycling. For example, where do mined and recycled resources fit in responsible supply chains as inputs to responsible production? What is required to ensure 3D production systems are resource efficient? How could more distributed models of production, enabled by additive manufacturing, change the geographical scale at which it is economic or desirable to close the loop? Examples are given to highlight the need for an integrated research agenda to address these questions and to foster Australian opportunities in the circular economy.

  14. Volcano emissions of trace metals, atmospheric deposition, and supply to biogeochemical cycles

    Science.gov (United States)

    Hinkley, T.; Thornber, C. R.; Matsumoto, A.

    2003-12-01

    Quiescently degassing (not exploding) volcanoes inject into the troposphere plumes that have remarkably high concentrations of ordinarily-rare, volatile trace metals. In pre-industrial times, these emissions appear to have accounted for the strong "enrichments" (relative to concentrations in crustal material or in ocean solute) of many such trace metals in the material deposited from the atmosphere. This has been shown by measuring the source strength of the emissions of metals from volcanoes, and comparing that to the amounts of the metals (excess over amounts accounted for by rock dust and sea salt) deposited onto high-latitude ice sheets: volcano degassing outputs of metals and deposition masses of metals to ice are comparable, on the basis of the masses (fluxes) and proportions of the metals, and from the proportions of lead (Pb) isotopes. There is indication that in modern industrial times the elevated trace metal fractions in the atmospheric material that has small particle size and long atmospheric residence time is still more strongly influenced by volcano emissions than by industrial emissions. Throughout earth's history it is likely that volcano emissions were a major control on the environmental background levels of trace elements, in which plants and animals evolved their tolerances to these mostly-poisonous substances.

  15. Theoretical study on hydrogenation catalysts containing a metal hydride as additional hydrogen supply

    NARCIS (Netherlands)

    Snijder, E.D.; Versteeg, G.F.; Swaaij, W.P.M. van

    1992-01-01

    A hypothetical hydrogenation catalyst consisting of porous, catalytically active particles embedded with metal hydride powder was evaluated. The metal hydride provides temporarily additional hydrogen if the mass transfer rate of the hydrogen to the internal of the particle is not sufficient. A numer

  16. Controlling optical response of metallic nanostructure

    Energy Technology Data Exchange (ETDEWEB)

    Grigorenko, Ilya [Los Alamos National Laboratory

    2008-01-01

    In this talk I am going to discuss the direct and inverse problems in nanoplasmonics in classical, and in particular quantum regimes of excitations. The inverse problem in nanoplasmonics is aimed to control the eigenspectrum, excitations,and other physical properties of nanosized quantum systems via controlling their size, shape, and structural composition. Using a combination of modern modeling techniques and optimization procedures, one can succeed to solve the inverse problem, namely, to find a nanostructure which has the desired functionality, or to find optimal control field in the presence of known nanostructured metallic surface.

  17. Enhancing Social Responsibility within Global Supply Chains: Is Legal Regulation the Optimal Solution?

    Directory of Open Access Journals (Sweden)

    Katerina Peterková

    2011-03-01

    Full Text Available This paper was presented at the first meeting of the NSU study group “Conceptions of ethical and social values in post-secular society: Towards a new ethical imagination in a cosmopolitan world society”, held on January 28-30, 2011 at Copenhagen Business School. First, this paper examines the voluntary (ethical v. mandatory (legal basis of corporate social responsibility (CSR. Second, it examines the relationship between CSR, law and business ethics. Third, it tries to answer the question if there is a need for a hard[2] legal regulation of CSR within international supply relationships or if ethical norms, e.g. expressed in the form of self-regulation, may better serve the purpose. And finally, it suggests possible ways for the future development of suitable regulatory methods for enhancing social standards within international supply chains. The questions are approached solely from the perspectives of legal theory and socio-legal analysis.

  18. Corporate Social Responsibility in Buyer-Supplier Relationships: Is it Beneficial for Top-Tier Suppliers to Market their Capability to Ensure a Responsible Supply Chain?

    National Research Council Canada - National Science Library

    Leppelt, Thomas; Foerstl, Kai; Hartmann, Evi

    2013-01-01

    This study assesses how top-tier suppliers market their capabilities to ensure a responsible upstream supply chain to their downstream buyers, and how the marketing of corporate social responsibility (CSR...

  19. Responses of carbon isotope discrimination in C4 plant to variable N and water supply

    Science.gov (United States)

    Yang, Hao; Li, Shenggong

    2016-04-01

    Understanding variations and underlying mechanisms of carbon isotope discrimination (Δ) in C4 species is critical for predicting the effects of change in C3/C4 ratio of plant community on ecosystem processes and functionning. However, little is known about the effects of soil resource gradients on Δ of C4 plants. To address Δ responses to drought and nitrogen supply, the leaf carbon isotope composition, bundle sheath leakiness (BLS), and leaf gas exchange (A, gs, Ci/Ca) were measured on Cleistogenes squarrosa, a dominant C4 species in the Inner Mongolia grassland. C. squarrosa were grown in controlled-environment pots from seed under a combination of water and N supply. High N availability and drought stimulated photosynthetic rate (A) and further decreased the ratio of internal and ambient CO2 concentrations (Ci/Ca) through increasing leaf N content. BLS was higher under high N supply and was unchanged by drought. There was significant interaction between N and water supply to affect BLS and Ci/Ca. Δ was negatively related to Ci/Ca and was positively related to BLS. Tradeoff between the responses of BLS and Ci/Ca to changing environmental conditions kept leaf Δ relatively stable, which was also supported by a field N addition experiment. Our results suggested leaf Δ of C4 plant was unchanged under variable water and N environment conditions although the operating efficiency of C4 pathway and CO2 concentration in photosynthesis were changed. Our findings have implications for predicting the change of C3/C4 ratio of plant community and understanding ecosystem processes and functionning.

  20. Maize maintains growth in response to decreased nitrate supply through a highly dynamic and developmental stage-specific transcriptional response

    KAUST Repository

    Plett, Darren

    2015-06-02

    Elucidation of the gene networks underlying the response to N supply and demand will facilitate the improvement of the N uptake efficiency of plants. We undertook a transcriptomic analysis of maize to identify genes responding to both a non-growth-limiting decrease in NO3- provision and to development-based N demand changes at seven representative points across the life cycle. Gene co-expression networks were derived by cluster analysis of the transcript profiles. The majority of NO3--responsive transcription occurred at 11 (D11), 18 (D18) and 29 (D29) days after emergence, with differential expression predominating in the root at D11 and D29 and in the leaf at D18. A cluster of 98 probe sets was identified, the expression pattern of which is similar to that of the high-affinity NO3- transporter (NRT2) genes across the life cycle. The cluster is enriched with genes encoding enzymes and proteins of lipid metabolism and transport, respectively. These are candidate genes for the response of maize to N supply and demand. Only a few patterns of differential gene expression were observed over the entire life cycle; however, the composition of the classes of the genes differentially regulated at individual time points was unique, suggesting tightly controlled regulation of NO3--responsive gene expression. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

  1. Supply of nutrients and productive responses in dairy cows given diets based on restrictively fermented silage

    Directory of Open Access Journals (Sweden)

    P. HUHTANEN

    2008-12-01

    Full Text Available The objective of this paper is to review research which has evaluated the feeding of dairy cows with diets containing large proportions of grass silage. In Finland, milk production systems evolved are based on the use of restrictively fermented silages. Higher potential yields, smaller production risks than with cereal grains, short grazing period and high digestibility of grasses grown in northern latitudes have facilitated this development. Factors affecting nutrient supply from these diets are discussed. Digestibility is determined mainly by the stage of maturity at harvesting and it is not markedly affected by the level of energy and protein supplementation. Intake of grass silage is influenced both by digestibility and fermentation characteristics. Efficiency of microbial synthesis is high in animals given diets based on restrictively fermented silage but rumen fermentation pattern is characterised by low molar proportions of propionate. Production responses to additional concentrate are relatively small, especially when the amount of concentrate exceeds 10 kg day-1. High substitution of silage dry matter (DM, negative associative effects on digestion and partitioning of energy towards body tissues account for small production responses. Protein supplementation has consistently increased milk protein yield but responses do not appear to be related to the level of milk production, silage crude protein content, amount of concentrate or stage of lactation. The new protein evaluation system provides an accurate prediction of protein yield with the typical Finnish dairy cow diets. The high slopes (ca. 0.5 between protein supply and milk protein yield within experiments suggest that protein supply is suboptimal and protein supplements are used with a high efficiency.;

  2. An analysis of elastic and plastic fruit growth of mango in response to various assimilate supplies.

    Science.gov (United States)

    Lechaudel, Mathieu; Vercambre, Gilles; Lescourret, Françoise; Normand, Frederic; Génard, Michel

    2007-02-01

    Changes in elastic and plastic components of mango (Mangifera indica L. cv 'Cogshall') fruit growth were analyzed with a model of fruit growth over time and in response to various assimilate supplies. The model is based on water relations (water potential and osmotic and turgor pressures) at the fruit level. Variation in elastic fruit growth was modeled as a function of the elastic modulus and variation in turgor pressure. Variation in plastic fruit growth was modeled using the Lockhart (1965) equation. In this model, plastic growth parameters (yield threshold pressure and cell wall extensibility) varied during fruit growth. Outputs of the model were diurnal and seasonal fruit growth, and fruit turgor pressure. These variables were simulated with good accuracy by the model, particularly the observed increase in fruit size with increasing availability of assimilate supply. Shrinkage was sensitive to the surface conductance of fruit peel, the elasticity modulus and the hydraulic conductivity of fruit, whereas fruit growth rate was highly sensitive to parameters linked to changes in wall extensibility and yield threshold pressure, regardless of the assimilate supply. According to the model, plastic growth was generally zero during the day and shrinkage and swelling were linked to the elastic behavior of the fruit. During the night, plastic and elastic growths were positive, resulting in fruit expansion.

  3. Absorption Kinetics and Subcellular Fractionation of Zinc in Winter Wheat in Response to Nitrogen Supply.

    Science.gov (United States)

    Nie, Zhaojun; Zhao, Peng; Wang, Jia; Li, Jinfeng; Liu, Hongen

    2017-01-01

    Nitrogen (N) is critical for zinc (Zn) absorption into plant roots; this in turn allows for Zn accumulation and biofortification of grain in winter wheat (Triticum aestivum L.), an important food crop. However, little is known about root morphology and subcellular Zn distribution in response to N treatment at different levels of Zn supply. In this study, two nutrient solution culture experiments were conducted to examine Zn accumulation, Zn absorption kinetics, root morphology, and Zn subcellular distribution in wheat seedlings pre-cultured with different N concentrations. The results showed positive correlations between N and Zn concentrations, and N and Zn accumulation, respectively. The findings suggested that an increase in N supply enhanced root absorption and the root-to-shoot transport of Zn. Nitrogen combined with the high Zn (Zn10) treatment increased the Zn concentration and consequently its accumulation in both shoots and roots. The maximum influx rate (Vmax), root length, surface area, and volume of 14-d-old seedlings, and root growth from 7 to 14 d in the medium N (N7.5) treatment were higher, but the Michaelis constant (Km) and minimum equilibrium concentrations (Cmin) in this treatment were lower than those in the low (N0.05) and high (N15) N treatments, when Zn was supplied at a high level (Zn10). Meanwhile, there were no pronounced differences in the above root traits between the N0.05Zn0 and N7.5Zn10 treatments. An increase in N supply decreased Zn in cell walls and cell organelles, while it increased Zn in the root soluble fraction. In leaves, an increase in N supply significantly decreased Zn in cell walls and the soluble fraction, while it increased Zn in cell organelles under Zn deficiency, but increased Zn distribution in the soluble fraction under medium and high Zn treatments. Therefore, a combination of medium N and high Zn treatments enhanced Zn absorption, apparently by enhancing Zn membrane transport and stimulating root development in

  4. Transcriptomic profiling of Arabidopsis gene expression in response to varying micronutrient zinc supply

    Directory of Open Access Journals (Sweden)

    Herlânder Azevedo

    2016-03-01

    Full Text Available Deficiency of the micronutrient zinc is a widespread condition in agricultural soils, causing a negative impact on crop quality and yield. Nevertheless, there is an insufficient knowledge on the regulatory and molecular mechanisms underlying the plant response to inadequate zinc nutrition [1]. This information should contribute to the development of plant-based solutions with improved nutrient-use-efficiency traits in crops. Previously, the transcription factors bZIP19 and bZIP23 were identified as essential regulators of the response to zinc deficiency in Arabidopsis thaliana [2]. A microarray experiment comparing gene expression between roots of wild-type and the mutant bzip19 bzip23, exposed to zinc deficiency, led to the identification of differentially expressed genes related with zinc homeostasis, namely its transport and plant internal translocation [2]. Here, we provide the detailed methodology, bioinformatics analysis and quality controls related to the microarray gene expression profiling published by Assunção and co-workers [2]. Most significantly, the present dataset comprises new experimental variables, including analysis of shoot tissue, and zinc sufficiency and excess supply. Thus, it expands from 8 to 42 microarrays hybridizations, which have been deposited at the Gene Expression Omnibus (GEO under the accession number GSE77286. Overall, it provides a resource for research on the molecular basis and regulatory events of the plant response to zinc supply, emphasizing the importance of Arabidopsis bZIP19 and bZIP23 transcription factors.

  5. High responsivity 4H-SiC based metal-semiconductor-metal ultraviolet photodetectors

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    4H-SiC based metal-semiconductor-metal (MSM) photodetectors with diverse spacing were designed, fabricated, and characterized, in which nickel Schottky contacts were needed. Current-voltage and spectral responsivity measurements were carried out at room temperature. The fabricated 4 μm-spacing device showed a very low dark current (0.25 pA at 5 V bias voltage), a typical responsivity of 0.103 A/W at 20 V, and a peak re-sponse wavelength at 290 nm. The fabricated devices held a high DUV to visible re-jection ratio of >103.

  6. The ratio of Zn to Cd supply as a determinant of metal-homeostasis gene expression in tobacco and its modulation by overexpressing the metal exporter AtHMA4

    Science.gov (United States)

    Barabasz, Anna; Klimecka, Maria; Kendziorek, Maria; Weremczuk, Aleksandra; Ruszczyńska, Anna; Bulska, Ewa; Antosiewicz, Danuta Maria

    2016-01-01

    This study links changes in the tobacco endogenous metal-homeostasis network caused by transgene expression with engineering of novel features. It also provides insight into the concentration-dependent mutual interactions between Zn and Cd, leading to differences in the metal partitioning between wild-type and transgenic plants. In tobacco, expression of the export protein AtHMA4 modified Zn/Cd root/shoot distribution, but the pattern depended on their concentrations in the medium. To address this phenomenon, the expression of genes identified by suppression subtractive hybridization and the Zn/Cd accumulation pattern were examined upon exposure to six variants of low/high Zn and Cd concentrations. Five tobacco metal-homeostasis genes were identified: NtZIP2, NtZIP4, NtIRT1-like, NtNAS, and NtVTL. In the wild type, their expression depended on combinations of low/high Zn and Cd concentrations; co-ordinated responses of NtZIP1, NtZIP2, and NtVTL were shown in medium containing 4 µM Cd, and at 0.5 µM versus 10 µM Zn. In transgenics, qualitative changes detected for NtZIP1, NtZIP4, NtIRT1-like, and NtVTL are considered crucial for modification of Zn/Cd supply-dependent Zn/Cd root/shoot distribution. Notwithstanding, NtVTL was the most responsive gene in wild-type and transgenic plants under all concentrations of Zn and Cd tested; thus it is a candidate gene for the regulation of metal cross-homeostasis processes involved in engineering new metal-related traits. PMID:27811086

  7. Endothelial Cellular Responses to Biodegradable Metal Zinc.

    Science.gov (United States)

    Ma, Jun; Zhao, Nan; Zhu, Donghui

    Biodegradable zinc (Zn) metals, a new generation of biomaterials, have attracted much attention due to their excellent biodegradability, bioabsorbability, and adaptability to tissue regeneration. Compared with magnesium (Mg) and iron (Fe), Zn exhibits better corrosion and mechanical behaviors in orthopedic and stent applications. After implantation, Zn containing material will slowly degrade, and Zn ions (Zn(2+)) will be released to the surrounding tissue. For stent applications, the local Zn(2+)concentration near endothelial tissue/cells could be high. However, it is unclear how endothelia will respond to such high concentrations of Zn(2+), which is pivotal to vascular remodeling and regeneration. Here, we evaluated the short-term cellular behaviors of primary human coronary artery endothelial cells (HCECs) exposed to a concentration gradient (0-140 μM) of extracellular Zn(2+). Zn(2+) had an interesting biphasic effect on cell viability, proliferation, spreading, and migration. Generally, low concentrations of Zn(2+) promoted viability, proliferation, adhesion, and migration, while high concentrations of Zn(2+) had opposite effects. For gene expression profiles, the most affected functional genes were related to cell adhesion, cell injury, cell growth, angiogenesis, inflammation, vessel tone, and coagulation. These results provide helpful information and guidance for Zn-based alloy design as well as the controlled release of Zn(2+)in stent and other related medical applications.

  8. Strategic and tactical determinants for South African platinum-group-metals supply

    CSIR Research Space (South Africa)

    McGill, JE

    2011-11-01

    Full Text Available for competitive future supply being derived from the eastern limb. 1 Introduction The mineral resources sector displays a careful balancing act between operation specific tactics designed to maximize shareholder returns; and overarching industry...-related strategies employed by various entities including country governments, global interest groups, and multi-national head offices. This balancing act of short-term business tactics juxtaposed along-side long-run strategic intent of the extraction sector...

  9. When falsified medicines enter the supply chain: description of an incident in Kenya and lessons learned for rapid response.

    Science.gov (United States)

    Cohn, Jennifer; von Schoen-Angerer, Tido; Jambert, Elodie; Arreghini, Guido; Childs, Michelle

    2013-01-01

    Falsified and substandard medicines present serious concerns for public health. We describe an event that occurred in late 2011 involving falsified antiretroviral medicines found in the supplies of Médecins Sans Frontières (MSF) projects in Kenya. We discuss factors contributing to these falsified medicines entering the supply chain as well as the response by MSF and others. We make recommendations to help defend against future episodes of entry of falsified medicines into the supply chain as well as comments on appropriate responses in cases of falsified medicines.

  10. Heavy Metal Accumulation and Ecological Responses of Turfgrass to Rubbish Compost with EDTA Addition

    Institute of Scientific and Technical Information of China (English)

    Li-An DUO; Yu-Bao GAO; Shu-Lan ZHAO

    2005-01-01

    Domestic rubbish compost is a complex-polluted system, containing multiple heavy metals,which limits its application. In the present study, Cr, Mn, Ni, Cu, Zn, Cd, and Pb accumulation and ecological responses of turfgrass to rubbish compost were investigated following the addition of EDTA. The results showed that the addition of EDTA significantly increased heavy metal accumulation in Lolium perenne L.and Festuca arundinacea L. Most heavy metal concentrations in L. perenne increased with increasing EDTA supply. The concentrations of Cr, Mn, Ni, Cu, and Cd in L. perenne were highest following the addition of 30 mmol/kg EDTA and the concentrations of Cr and Ni at this point reached concentrations of1914.17 and 521.25 μg/g, respectively. When the EDTA level was < 20 mmol/kg, the accumulation of most heavy metals in F. arundinacea increased with increasing EDTA supply, but showed a tendency to decrease at EDTA concentrations >20 mmol/kg. The highest concentrations of Mn, Ni, Cu, and Zn in F.arundinacea reached 268.01, 110.94, 161.52 and 1 354.97 μg/g, respectively, following the addition of 20mmol/kg EDTA. The EDTA-induced increase in the accumulation of heavy metals in turfgrass was plantand metal-specific. L. perenne had a relatively high ability to accumulate Cr, Ni, and Zn. The highest Zn concentration was 2 979.58 μg/g and, following the addition of EDTA, the concentrations of the three metals were increased 26.23, 20.03, and 10.49-fold, respectively, compared with control. However, F. arundinacea showed a high ability to accumulate Cr, with the highest concentration (596.02 μg/g) seen following the addition of 30 mmol/kg EDTA; the concentration of Cr increased 15.51-fold compared with control. With EDTA addition, ecological responses of both turfgrass species showed that EDTA at concentrations <10mmol/kg increased seed germination and aboveground net primary production (ANP) of L. perenne and slightly inhibited those of F.arundinacea, but EDTA at

  11. Transient response in longitudinal grain size to reduced sediment supply in a large river

    Science.gov (United States)

    Singer, Michael

    2010-05-01

    Bed material grain size is an important degree of freedom in fluvial systems as they adjust to system-wide perturbations such as sediment supply changes. However, little is known about processes and patterns of such adjustment in longitudinal grain size sorting in large rivers. This research uses unprecedented datasets collected in a large fluvial system to investigate transient response to recent supply changes associated with anthropogenic activities. Separate fining trends for gravel and fines, a protracted gravel-sand (G-S) transition, and bed patchiness identified in Singer (2008) were interrogated using output from a hydraulic model with grain size distributions (GSDs) extracted from ~125 cross sections spanning ~400 river kilometers of the Sacramento River, California. The analysis suggests that interactions between hydraulics, bed material sorting, and sediment flux explain these previously identified anomalies. Highest values of sorting occur in the G-S transition and represent the overlap of separate fining trends for gravel and fines, where the long profile is jagged with evidence of progressive incision. Much of the sediment in this poorly sorted zone is organized into patches, where transport apparently occurs as bedload sheets. Patchiness occurs over short length scales leading to strong differences in entrainment and flux, regardless of hydraulic conditions. A modified Shields stress is proposed that is scaled by GSD sorting to improve characterization of entrainment/disentrainment. Sediment flux calculations based on an equation sensitive bed material conditions (Singer and Dunne, 2004) reveal a strong relationship between fine sediment flux and d90, suggesting that the efficiency of fine patch flux controls bed material bed surface roughness. Results are in part consistent with Paola and Seal (1995) suggesting that patches are a result of overlapping pdfs of shear stress and sorting and with Ferguson (2003) in that the final end of the protracted G

  12. [Characteristics of sediment heavy metal pollution in three water supply reservoirs in Huizhou, Guangdong Province of South China].

    Science.gov (United States)

    Chen, Xiu-Kang; Zhang, Hua-Jun; Gu, Ji-Guang; Hu, Ren; Yang, Hao-Wen; Chen, Jing-An

    2012-05-01

    To understand the present status of the heavy metal (Cr, Cu, Zn, Cd, Pb and Hg) pollution of the sediments in water supply reservoirs in Huizhou, sediment cores were sampled from three representative reservoirs. The heavy metal concentrations were analyzed by ICP-MS, and the pollution status was assessed by geo-accumulation index (Igeo) and potential ecological risk index (RI). In the meantime, the possible sources of the heavy metals were analyzed by the principal component analysis (PCA). In the sediments of the three reservoirs, the test heavy metals had different vertical distribution, some had less change, the others decreased or increased with depth, and the distribution patterns differed with the reservoirs. According to the Igeo, the sediments in the reservoirs were seriously polluted by Zn and Pb (Zn: 49.98-640.29 mg x kg(-1); Pb: 21.94-300.66 mg x kg(-1)), reaching slight to high pollution, and the middle or bottom part of the sediments was slightly polluted by Cu (16.85-45.46 mg x kg(-1)). On the whole, the sediments were not polluted by Cr, Cd and Hg. According to the RI and the potential ecological risk coefficient [Er(i)], the sediments in the three reservoirs were under low potential ecological risk. Based on the PCA and relevant information, the human activities such as mining and smelting, urbanization, and agriculture and forestry had great contribution to the heavy metal pollution. The Zn and Pb pollution mainly originated from mining and smelting, Pb pollution also came from motor vehicle exhaust emission and domestic wastes, and Cu pollution mainly derived from agriculture and forestry.

  13. Variation for N uptake system in maize: genotypic response to N supply

    Directory of Open Access Journals (Sweden)

    Trevor eGarnett

    2015-11-01

    Full Text Available An understanding of the adaptations made by plants in their nitrogen (N uptake systems in response to reduced N supply is important to the development of cereals with enhanced N uptake efficiency (NUpE. Twenty seven diverse genotypes of maize (Zea mays, L. were grown in hydroponics for three weeks with limiting or adequate N supply. Genotype response to N was assessed on the basis of biomass characteristics and the activities of the nitrate (NO3- and ammonium (NH4+ high-affinity transport systems. Genotypes differed greatly for the ability to maintain biomass with reduced N. Genotypes that maintained biomass at reduced N maintained net N uptake with no change in size of the root relative to the shoot. The root uptake capacity for both NO3- and NH4+ increased with reduced N. Transcript levels of putative NO3- and NH4+ transporter genes in the root tissue of a subset of the genotypes revealed that is was predominately putative ZmNRT2s whose transcript levels responded to N treatments. The correlation between the ratio of transcripts of ZmNRT2.2 between the two N levels and a genotypes ability to maintain biomass with reduced N suggests a role in enhancing N uptake efficiency. The observed variation in the ability to capture N at low N provides scope for both improving NUpE in maize and also to better understand the N uptake system in cereals.

  14. Supply chain responsibilities and the need for an integrative ethic Management in Emerging Economies

    Directory of Open Access Journals (Sweden)

    Lothar Auchter

    2015-03-01

    Full Text Available The economic importance of the Indian Textile and Clothing (T&C industry is unquestioned. It is one of the second largest employment generating industry, after agriculture, with direct employment of over 35 million people. Tamil Nadu accounts for over 65% of the total number spinning units in India and has been reported exploiting young women workers in the spinning and textile units what is called the “Sumangali Scheme”. “Sumangali” in Tamil means ‘happily married woman’. Globalization confronts decision-makers in connection with global conditions in identifying labour standards that can serve as guidelines for corporations producing or outsourcing outside of their home country. The Article shows that in a globalized business world the concept of a conventional corporate ethic system to put all energy into the development of codes of conduct, and ethical audits and sustainability reporting falls short. This applies to industries like the Tamil Nadu textile industry, as there is no clarity with regard to the causal factors and the key players in the supply chain of such a complex social system. The Integrative Social Contract Theory (ISCT allows understanding the problem of Supply-Chain Responsibilities as a contractual relationship that denotes concrete moral responsibilities.

  15. Heavy Metal Stress and Some Mechanisms of Plant Defense Response

    Directory of Open Access Journals (Sweden)

    Abolghassem Emamverdian

    2015-01-01

    Full Text Available Unprecedented bioaccumulation and biomagnification of heavy metals (HMs in the environment have become a dilemma for all living organisms including plants. HMs at toxic levels have the capability to interact with several vital cellular biomolecules such as nuclear proteins and DNA, leading to excessive augmentation of reactive oxygen species (ROS. This would inflict serious morphological, metabolic, and physiological anomalies in plants ranging from chlorosis of shoot to lipid peroxidation and protein degradation. In response, plants are equipped with a repertoire of mechanisms to counteract heavy metal (HM toxicity. The key elements of these are chelating metals by forming phytochelatins (PCs or metallothioneins (MTs metal complex at the intra- and intercellular level, which is followed by the removal of HM ions from sensitive sites or vacuolar sequestration of ligand-metal complex. Nonenzymatically synthesized compounds such as proline (Pro are able to strengthen metal-detoxification capacity of intracellular antioxidant enzymes. Another important additive component of plant defense system is symbiotic association with arbuscular mycorrhizal (AM fungi. AM can effectively immobilize HMs and reduce their uptake by host plants via binding metal ions to hyphal cell wall and excreting several extracellular biomolecules. Additionally, AM fungi can enhance activities of antioxidant defense machinery of plants.

  16. Development of closed-loop supply chain network in terms of corporate social responsibility.

    Science.gov (United States)

    Pedram, Ali; Pedram, Payam; Yusoff, Nukman Bin; Sorooshian, Shahryar

    2017-01-01

    Due to the rise in awareness of environmental issues and the depletion of virgin resources, many firms have attempted to increase the sustainability of their activities. One efficient way to elevate sustainability is the consideration of corporate social responsibility (CSR) by designing a closed loop supply chain (CLSC). This paper has developed a mathematical model to increase corporate social responsibility in terms of job creation. Moreover the model, in addition to increasing total CLSC profit, provides a range of strategic decision solutions for decision makers to select a best action plan for a CLSC. A proposed multi-objective mixed-integer linear programming (MILP) model was solved with non-dominated sorting genetic algorithm II (NSGA-II). Fuzzy set theory was employed to select the best compromise solution from the Pareto-optimal solutions. A numerical example was used to validate the potential application of the proposed model. The results highlight the effect of CSR in the design of CLSC.

  17. Variation for N Uptake System in Maize: Genotypic Response to N Supply

    KAUST Repository

    Garnett, Trevor

    2015-11-09

    An understanding of the adaptations made by plants in their nitrogen (N) uptake systems in response to reduced N supply is important to the development of cereals with enhanced N uptake efficiency (NUpE). Twenty seven diverse genotypes of maize (Zea mays, L.) were grown in hydroponics for 3 weeks with limiting or adequate N supply. Genotypic response to N was assessed on the basis of biomass characteristics and the activities of the nitrate (NO−3) and ammonium (NH+4) high-affinity transport systems. Genotypes differed greatly for the ability to maintain biomass with reduced N. Although, the N response in underlying biomass and N transport related characteristics was less than that for biomass, there were clear relationships, most importantly, lines that maintained biomass at reduced N maintained net N uptake with no change in size of the root relative to the shoot. The root uptake capacity for both NO−3 and NH+4 increased with reduced N. Transcript levels of putative NO−3 and NH+4 transporter genes in the root tissue of a subset of the genotypes revealed that predominately ZmNRT2 transcript levels responded to N treatments. The correlation between the ratio of transcripts of ZmNRT2.2 between the two N levels and a genotype\\'s ability to maintain biomass with reduced N suggests a role for these transporters in enhancing NUpE. The observed variation in the ability to capture N at low N provides scope for both improving NUpE in maize and also to better understand the N uptake system in cereals.

  18. In silico analysis of Clostridium acetobutylicum ATCC 824 metabolic response to an external electron supply.

    Science.gov (United States)

    Gallardo, Roberto; Acevedo, Alejandro; Quintero, Julián; Paredes, Ivan; Conejeros, Raúl; Aroca, Germán

    2016-02-01

    The biological production of butanol has become an important research field and thanks to genome sequencing and annotation; genome-scale metabolic reconstructions have been developed for several Clostridium species. This work makes use of the iCAC490 model of Clostridium acetobutylicum ATCC 824 to analyze its metabolic capabilities and response to an external electron supply through a constraint-based approach using the Constraint-Based Reconstruction Analysis Toolbox. Several analyses were conducted, which included sensitivity, production envelope, and phenotypic phase planes. The model showed that the use of an external electron supply, which acts as co-reducing agent along with glucose-derived reducing power (electrofermentation), results in an increase in the butanol-specific productivity. However, a proportional increase in the butyrate uptake flux is required. Besides, the uptake of external butyrate leads to the coupling of butanol production and growth, which coincides with results reported in literature. Phenotypic phase planes showed that the reducing capacity becomes more limiting for growth at high butyrate uptake fluxes. An electron uptake flux allows the metabolism to reach the growth optimality line. Although the maximum butanol flux does not coincide with the growth optimality line, a butyrate uptake combined with an electron uptake flux would result in an increased butanol volumetric productivity, being a potential strategy to optimize the production of butanol by C. acetobutylicum ATCC 824.

  19. Corporate Social Responsibility in Buyer-Supplier Relationships: Is it Beneficial for Top-Tier Suppliers to Market their Capability to Ensure a Responsible Supply Chain?

    OpenAIRE

    Thomas Leppelt; Kai Foerstl; Evi Hartmann

    2013-01-01

    This study assesses how top-tier suppliers market their capabilities to ensure a responsible upstream supply chain to their downstream buyers, and how the marketing of corporate social responsibility (CSR)-related supply management practices affects the reputation of top-tier suppliers in business-to-business (B2B) markets. In a cross-functional multiple-case study involving marketing, purchasing, and sustainability executives of five supplier organizations in Central Europe, we explored four...

  20. Analysis of residential, industrial and commercial sector responses to potential electricity supply constraints in the 1990s

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, Z.J.; Fang, J.M.; Lyke, A.J.; Krudener, J.R.

    1986-09-01

    There is considerable debate over the ability of electric generation capacity to meet the growing needs of the US economy in the 1990s. This study provides new perspective on that debate and examines the possibility of power outages resulting from electricity supply constraints. Previous studies have focused on electricity supply growth, demand growth, and on the linkages between electricity and economic growth. This study assumes the occurrence of electricity supply shortfalls in the 1990s and examines the steps that homeowners, businesses, manufacturers, and other electricity users might take in response to electricity outages.

  1. Metabolic and structural response of hyporheic microbial communities to variations in supply of dissolved organic matter

    Science.gov (United States)

    Findlay, S.E.G.; Sinsabaugh, R. L.; Sobczak, W.V.; Hoostal, M.

    2003-01-01

    Hyporheic sediment bacterial communities were exposed to dissolved organic matter (DOM) from a variety of sources to assess the interdependence of bacterial metabolism and community composition. Experiments ranged from small-scale core perfusions with defined compounds (glucose, bovine serum albumin) to mesocosms receiving natural leaf leachate or water from different streams. Response variables included bacterial production, oxygen consumption, extracellular enzyme activity, and community similarity as manifest by changes in banding patterns of randomly amplified polymorphic DNA (RAPD). All DOM manipulations generated responses in at least one metabolic variable. Additions of both labile and recalcitrant materials increased either oxygen consumption, production, or both depending on background DOM. Enzyme activities were affected by both types of carbon addition with largest effects from the labile mixture. Cluster analysis of RAPD data showed strong divergence of communities exposed to labile versus recalcitrant DOM. Additions of leaf leachate to mesocosms representing hyporheic flow-paths caused increases in oxygen consumption and some enzyme activities with weaker effects on production. Community structure yeas strongly affected; samples from the leachate-amended mesocosms clustered separately from the control samples. In mesocosms receiving water from streams ranging in DOC (0.5-4.5 mg L-1), there were significant differences in bacterial growth, oxygen consumption, and enzyme activities. RAPD analysis showed strongest clustering of samples by stream type with more subtle effects of position along the flowpaths. Responses in community metabolism were always accompanied by shifts in community composition, suggesting carbon supply affects both functional and structural attributes of hyporheic bacterial communities.

  2. Lecture-Tutorial Coherency: Student-Supplied Written-Responses As Indicators Of Future Success

    Science.gov (United States)

    Eckenrode, Jeff; Welch, J. D.; Saldivar, H.; Laird, J.; Prather, E. E.; Cormier, S.; Wallace, C. S.; Brissenden, G.; Collaboration of Astronomy Teaching Scholars CATS

    2012-01-01

    The Lecture-Tutorial Coherency Project investigates the importance of correctness and coherency in Lecture-Tutorial (LT) responses and their role in students’ understanding of introductory astronomy content. Astronomy education researchers, including students from the Ambassador Program (former Astro 101 students who later became instructional assistants for Astro 101), designed rubrics geared towards assessing the correctness and coherency of student-supplied written-responses for specific LT questions. We used these rubrics to score the LT responses of over 1300 students. We then looked for a correlation between a student's ability to connect novel pieces of reasoning together to form a coherent argument in their LT and their performance on exam questions with closely aligned content. We will present results from our study. This material is based in part upon work supported by the National Science Foundation under Grant No. 0715517, a CCLI Phase III Grant for the Collaboration of Astronomy Teaching Scholars (CATS). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.

  3. Understanding the biological responses of nanostructured metals and surfaces

    Science.gov (United States)

    Lowe, Terry C.; Reiss, Rebecca A.

    2014-08-01

    Metals produced by Severe Plastic Deformation (SPD) offer distinct advantages for medical applications such as orthopedic devices, in part because of their nanostructured surfaces. We examine the current theoretical foundations and state of knowledge for nanostructured biomaterials surface optimization within the contexts that apply to bulk nanostructured metals, differentiating how their microstructures impact osteogenesis, in particular, for Ultrafine Grained (UFG) titanium. Then we identify key gaps in the research to date, pointing out areas which merit additional focus within the scientific community. For example, we highlight the potential of next-generation DNA sequencing techniques (NGS) to reveal gene and non-coding RNA (ncRNA) expression changes induced by nanostructured metals. While our understanding of bio-nano interactions is in its infancy, nanostructured metals are already being marketed or developed for medical devices such as dental implants, spinal devices, and coronary stents. Our ability to characterize and optimize the biological response of cells to SPD metals will have synergistic effects on advances in materials, biological, and medical science.

  4. A multistimuli-responsive photochromic metal-organic gel.

    Science.gov (United States)

    Wei, Shi-Chao; Pan, Mei; Li, Kang; Wang, Sujuan; Zhang, Jianyong; Su, Cheng-Yong

    2014-04-02

    A photochromic metal-organic gel with thermo-, photo-, and anion-responsive behavior is obtained. Unusually, heating of the Al-ligand solution leads to gel formation and cooling to room temperature reverses the process to reform the solution. The gel is sensitive to weakly coordinating anions. Additionally, reversible photochromic transformations take place both in the solution and gel states, accompanied by reversibly switched luminescence.

  5. The role of the concept of corporate social responsibility in building relationships and in the supply chain

    Directory of Open Access Journals (Sweden)

    Maciej Urbaniak

    2015-06-01

    Full Text Available   Background: The aim of this article is to determine the importance of the concept of corporate social responsibility in building partnerships in the supply chain. In the recent period, one could notice that more and more international companies implementing their strategies based on the concept of sustainable development are evaluating and qualifying their suppliers basing on standards of ethics in business. Methods: This paper analyzed the requirements of the multinationals companies towards their suppliers in implementing elements of the concept of corporate social responsibility. Results: The results of the analyzes which were presented on practical examples show that buyers define to suppliers, very often detailed, standards for ethical conduct for suppliers (Supplier Conduct Principles, Principles and Standards of Ethical Supply Management Conduct and guides for their implementation (Supply Chain CSR Deployment guidebook, Purchasing Way, Supplier Sustainability program Manual, organizing programs (Supply Chain Social Responsibility programs, implementing the Supplier Responsibility projects and developing a checklist (Supply Chain CSR Checklist for self-evaluation of providers. Conclusions: When observing global trends one could notice that recently more and more suppliers are evaluated in terms of the fulfillment of the principles of sustainable development, guided by the economic aspects (requiring high technical quality, reliability of supply, competitive price, stable financial position, compliance with legal requirements, environmental aspects, as well as social aspects (principles based on the idea of the Global Compact. One could also perceive that many international companies signing contracts with suppliers require them to sign a declaration, obligating them to introduce the concept of corporate social responsibility by applying the principles contained in Statement on Business Practices and in compliance with the requirements

  6. Development of closed–loop supply chain network in terms of corporate social responsibility

    Science.gov (United States)

    Pedram, Payam; Yusoff, Nukman Bin; Sorooshian, Shahryar

    2017-01-01

    Due to the rise in awareness of environmental issues and the depletion of virgin resources, many firms have attempted to increase the sustainability of their activities. One efficient way to elevate sustainability is the consideration of corporate social responsibility (CSR) by designing a closed loop supply chain (CLSC). This paper has developed a mathematical model to increase corporate social responsibility in terms of job creation. Moreover the model, in addition to increasing total CLSC profit, provides a range of strategic decision solutions for decision makers to select a best action plan for a CLSC. A proposed multi-objective mixed-integer linear programming (MILP) model was solved with non-dominated sorting genetic algorithm II (NSGA-II). Fuzzy set theory was employed to select the best compromise solution from the Pareto-optimal solutions. A numerical example was used to validate the potential application of the proposed model. The results highlight the effect of CSR in the design of CLSC. PMID:28384250

  7. Social Corporate Responsibility regarding Household Consumer Satisfaction with the Electric Power Supply Services

    Directory of Open Access Journals (Sweden)

    Maria-Ana Georgescu

    2014-02-01

    Full Text Available The issue of the practical manifestation of corporate social responsibility towards consumers is highly important to the socio-economic reality in Romania. The present paper is the result of an investigation carried out in this field and it is distinguished by two aspects. The first aspect is its target audience used for research - household consumers of electricity, who can be called "vulnerable", captive consumers. The second aspect is the specificity of the electricity market. The aim of the research was to study the relationship between corporate social responsibility, instantiated by the quality of services provided by S.C. Electrica S.A. – Electrica Distribution and Supply South Transylvania and the consumers' loyalty towards the company, in case other electricity suppliers emerge. A subsidiary aspect was the generation of a database having an impact on customer retention. We have carried out some quantitative research, based on the survey method, having a sample of 521 household consumers from the Mures County. The study we carried out proves that consumer satisfaction, their degree of satisfaction under different aspects, is a way of gaining their trust on this particular market. Those consumers with a higher degree of trust in the company are more loyal. This will result in reducing migration to another electricity supplier, in the future, when all household consumers become eligible.

  8. Nonlinear THz response of metallic armchair graphene nanoribbon superlattices

    Science.gov (United States)

    Wang, Yichao; Andersen, David R.

    2016-11-01

    We study the third order THz nonlinear response of metallic armchair graphene nanoribbon superlattices in the presence of an elliptically-polarized excitation field using the time dependent perturbation theory. For a one-dimensional Kronig-Penney potential of infinite length, the nonlinear response can be described perturbatively by a low energy \\mathbf{k}\\centerdot \\mathbf{p} N-photon coupling model. Remarkably, as shown by Burset et al the energy dispersion of the metallic band in the direction parallel to the superlattice wavevector is independent of the applied superlattice potential while the energy dispersion in the direction perpendicular to the superlattice wavevector depends strongly on the superlattice parameters. As a result, we predict novel behavior for the nonlinear response of single layer metallic acGNR superlattices to an applied elliptically-polarized electric field. Our work shows that the superlattice potential, periodicity, Fermi level, excitation field polarization state, and temperature all play a significant role in the resulting THz nonlinear conductances.

  9. Response of frugivorous primates to changes in fruit supply in a northern Amazonian forest.

    Science.gov (United States)

    Mourthé, I

    2014-08-01

    Few attempts have been made to understand how spatiotemporal changes in fruit supply influence frugivores in tropical forests. The marked spatiotemporal variation in fruit supply can affect frugivore abundance and distribution, but studies addressing the effects of this variation on primates are scarce. The present study aimed to investigate how the spatiotemporal distribution of fruits influences the local distribution of three frugivorous primates in the eastern part of the Maracá Ecological Station, a highly seasonal Amazonian rainforest. Specifically, it was hypothesised that primate distribution will track changes in fruit supply, resulting that sites with high fruit availability should be heavily used by primates. During a 1-year study, fruit supply (ground fruit surveys) and primate density (line-transects) were monitored in twelve 2 km-long transects at monthly intervals. Fruit supply varied seasonally, being low during the dry season. The density of Ateles belzebuth was positively related to fruit supply during fruit shortage, but Cebus olivaceus and Alouatta macconnelli did not follow the same pattern. The supply of Sapotaceae fruit was an important component determining local distribution of A. belzebuth during the overall fruit shortage. Highly frugivorous primates such as A. belzebuth respond to seasonal decline in fruit supply by congregating at places with high fruit supply in this forest, particularly, those with many individuals of species of Sapotaceae. This study underscores the importance of small-scale spatiotemporal changes of fruit supply as a key component of frugivorous primate ecology in highly seasonal environments.

  10. A practical approach to implementing CSR in the electronics industry: global supply chain management focusing on corporate social responsibility

    Energy Technology Data Exchange (ETDEWEB)

    Jamieson, S.; Rice, G. [Panasonic Mobile Communication Development of Europe (PMCDE) (United Kingdom); Hilbron, R. [Vodafone Group Plc (United Kingdom); Clift, R.; Wehrmeyer, W. [Centre for Environmental Strategy, Univ. of Surrey (United Kingdom)

    2004-07-01

    This paper covers a co-operative investigation undertaken by Vodafone Plc and Panasonic Mobile Communications (PMC); applying Corporate Social Responsibility (CSR) principles in an actual assessment of the supply chain. Together, we carried out an informal CSR assessment on a Panasonic mobile phone handset manufacturing facility in the Philippines. CSR issues vary with geographical and cultural region. By researching CSR concerns typically encountered in the region, focal points of business performance for the Philippines investigation were identified. These are detailed in the paper. A key benefit from this assessment was the increased understanding of the management of the indirect CSR issues within the supply chain. This understanding is essential when developing a system for CSR supply-chain management. This paper will describe this exercise and its findings and will suggest future steps necessary to successfully integrate CSR principles though the global supply chain. (orig.)

  11. Collaborative ICT ventures and the implementation of responsive automotive supply networks

    OpenAIRE

    Stone, Gareth; Howard, Mickey; Miemczyk, Joe; Graves, Andrew

    2008-01-01

    This research paper explores the generic barriers which govern supply chain integration. Four automotive cases illustrate the motivations and barriers that emerged during the implementation phase of collaborative Information Communication Technology (ICT) ventures. The results indicate the reasons for the failure of ICT as the solution to collaborative supply chain integration. We show that ICT, in relation to Supply Chain Collaboration (SCC), is still at an embryonic stage of development. Re...

  12. Characterization of root response to phosphorus supply from morphology to gene analysis in field-grown wheat.

    Science.gov (United States)

    Teng, Wan; Deng, Yan; Chen, Xin-Ping; Xu, Xiao-Feng; Chen, Ri-Yuan; Lv, Yang; Zhao, Yan-Yan; Zhao, Xue-Qiang; He, Xue; Li, Bin; Tong, Yi-Ping; Zhang, Fu-Suo; Li, Zhen-Sheng

    2013-03-01

    The adaptations of root morphology, physiology, and biochemistry to phosphorus supply have been characterized intensively. However, characterizing these adaptations at molecular level is largely neglected under field conditions. Here, two consecutive field experiments were carried out to investigate the agronomic traits and root traits of wheat (Triticum aestivum L.) at six P-fertilizer rates. Root samples were collected at flowering to investigate root dry weight, root length density, arbusular-mycorrhizal colonization rate, acid phosphatase activity in rhizosphere soil, and expression levels of genes encoding phosphate transporter, phosphatase, ribonucleases, and expansin. These root traits exhibited inducible, inhibitory, or combined responses to P deficiency, and the change point for responses to P supply was at or near the optimal P supply for maximum grain yield. This research improves the understanding of mechanisms of plant adaptation to soil P in intensive agriculture and provides useful information for optimizing P management based on the interactions between soil P dynamics and root processes.

  13. Histological characterization of periprosthetic tissue responses for metal-on-metal hip replacement.

    Science.gov (United States)

    Phillips, Eual A; Klein, Gregg R; Cates, Harold E; Kurtz, Steven M; Steinbeck, Marla

    2014-01-01

    The histology of periprosthetic tissue from metal-on-metal (MOM) hip devices has been characterized using a variety of methods. The purpose of this study was to compare and evaluate the suitability of two previously developed aseptic lymphocyte-dominated vasculitis-associated lesions (ALVAL) scoring systems for periprosthetic hip tissue responses retrieved from MOM total hip replacement (THR) systems revised for loosening. Two ALVAL scoring systems (Campbell and Oxford) were used to perform histological analyses of soft tissues from 17 failed MOM THRs. The predominant reactions for this patient cohort were macrophage infiltration and necrosis, with less than half of the patients (41%) showing a significant lymphocytic response or a high ALVAL reaction (6%). Other morphological changes varied among patients and included hemosiderin accumulation, cartilage formation, and heterotopic ossification. Both scoring systems are useful for correlating macrophage and lymphocyte responses and for comparison with the other; however, given the diversity and variability of the current responses, the Oxford-ALVAL system is more suitable for scoring tissues from MOM THR patients revised for loosening. It is important that standardized methods of scoring MOM tissue responses be used consistently so multiple study results can be compared and a consensus can be generated.

  14. The influence of food supply on the response of Olympia oyster larvae to ocean acidification

    Directory of Open Access Journals (Sweden)

    A. Hettinger

    2013-10-01

    Full Text Available Increases in atmospheric carbon dioxide drive accompanying changes in the marine carbonate system as carbon dioxide (CO2 enters seawater and alters ocean pH (termed "ocean acidification". However, such changes do not occur in isolation, and other environmental factors have the potential to modulate the consequences of altered ocean chemistry. Given that physiological mechanisms used by organisms to confront acidification can be energetically costly, we explored the potential for food supply to influence the response of Olympia oyster (Ostrea lurida larvae to ocean acidification. In laboratory experiments, we reared oyster larvae under a factorial combination of pCO2 and food level. Elevated pCO2 had negative effects on larval growth, total dry weight, and metamorphic success, but high food availability partially offset these influences. The combination of elevated pCO2 and low food availability led to the greatest reduction in larval performance. However, the effects of food and pCO2 interacted additively rather than synergistically, indicating that they operated independently. Despite the potential for abundant resources to counteract the consequences of ocean acidification, impacts were never completely negated, suggesting that even under conditions of enhanced primary production and elevated food availability, impacts of ocean acidification may still accrue in some consumers.

  15. Population responses of small mammals to food supply and predators: a global meta-analysis.

    Science.gov (United States)

    Prevedello, Jayme A; Dickman, Chris R; Vieira, Marcus V; Vieira, Emerson M

    2013-09-01

    1. The relative importance of food supply and predation as determinants of animal population density is a topic of enduring debate among ecologists. To address it, many studies have tested the potential effects of food on population density by experimentally supplementing natural populations, with much focus on terrestrial vertebrates, especially small mammals. 2. Here we perform a meta-analysis of such experiments, testing two complementary hypotheses: (i) small mammal populations are bottom-up limited and (ii) population increases in response to food supplementation are constrained by predation, a top-down limitation. 3. In the 148 experiments recorded, food supplementation had an overall positive and significant effect, increasing population densities by 1.5-fold. Larger population increases occurred when predation was reduced and populations were open to immigration. Predation appeared to be unimportant when populations were closed to immigration. Immigration was the major mechanism underlying increases in abundance by increasing local population density and crowding. Contributions of increased reproductive rate could be detected, but were minor compared to immigration, and no effects were detected from survival. 4. Our analyses support the view that animal population density is determined by both bottom-up and top-down forces. They also suggest the possibility that food supplementation experiments might unintentionally create ecological traps by aggregating both prey and predators in small areas of the landscape. We suggest an alternative experimental design to increase the contribution that food supplementation experiments can make in future.

  16. Labor supply responses to large social transfers: Longitudinal evidence from South Africa.

    Science.gov (United States)

    Ardington, Cally; Case, Anne; Hosegood, Victoria

    2009-01-01

    In many parts of the developing world, rural areas exhibit high rates of unemployment and underemployment. Understanding what prevents people from migrating to find better jobs is central to the development process. In this paper, we examine whether binding credit constraints and childcare constraints limit the ability of households to send labor migrants, and whether the arrival of a large, stable source of income - here, the South African old-age pension - helps households to overcome these constraints. Specifically, we quantify the labor supply responses of prime-aged individuals to changes in the presence of pensioners, using longitudinal data collected in KwaZulu-Natal. Our ability to compare households and individuals before and after pension receipt, and pension loss, allows us to control for a host of unobservable household and individual characteristics that may determine labor market behavior. We find that large cash transfers to elderly South Africans lead to increased employment among prime-aged members of their households, a result that is masked in cross-sectional analysis by differences between pension and non-pension households. Pension receipt also influences where this employment takes place. We find large, significant effects on labor migration upon pension arrival. The pension's impact is attributable both to the increase in household resources it represents, which can be used to stake migrants until they become self-sufficient, and to the presence of pensioners who can care for small children, which allows prime-aged adults to look for work elsewhere.

  17. The influence of food supply on the response of Olympia oyster larvae to ocean acidification

    Directory of Open Access Journals (Sweden)

    A. Hettinger

    2013-03-01

    Full Text Available Increases in atmospheric carbon dioxide drive accompanying changes in the marine carbonate system as carbon dioxide (CO2 enters seawater and alters its pH (termed "ocean acidification". However, such changes do not occur in isolation, and other environmental factors have the potential to modulate the consequences of altered ocean chemistry. Given that physiological mechanisms used by organisms to confront acidification can be energetically costly, we explored the potential for food supply to influence the response of Olympia oyster (Ostrea lurida larvae to ocean acidification. In laboratory experiments, we reared oyster larvae under a factorial combination of pCO2 and food level. High food availability offset the negative consequences of elevated pCO2 on larval shell growth and total dry weight. Low food availability, in contrast, exacerbated these impacts. In both cases, effects of food and pCO2 interacted additively rather than synergistically, indicating that they operated independently. Despite the potential for abundant resources to counteract the consequences of ocean acidification, impacts were never completely negated, suggesting that even under conditions of enhanced primary production and elevated food availability, impacts of ocean acidification may still accrue in some consumers.

  18. China's Rare Earth Supply Chain: Illegal Production, and Response to new Cerium Demand

    Science.gov (United States)

    Nguyen, Ruby Thuy; Imholte, D. Devin

    2016-07-01

    As the demand for personal electronic devices, wind turbines, and electric vehicles increases, the world becomes more dependent on rare earth elements. Given the volatile, Chinese-concentrated supply chain, global attempts have been made to diversify supply of these materials. However, the overall effect of supply diversification on the entire supply chain, including increasing low-value rare earth demand, is not fully understood. This paper is the first attempt to shed some light on China's supply chain from both demand and supply perspectives, taking into account different Chinese policies such as mining quotas, separation quotas, export quotas, and resource taxes. We constructed a simulation model using Powersim Studio that analyzes production (both legal and illegal), production costs, Chinese and rest-of-world demand, and market dynamics. We also simulated new demand of an automotive aluminum-cerium alloy in the US market starting from 2018. Results showed that market share of the illegal sector has grown since 2007-2015, ranging between 22% and 25% of China's rare earth supply, translating into 59-65% illegal heavy rare earths and 14-16% illegal light rare earths. There will be a shortage in certain light and heavy rare earths given three production quota scenarios and constant demand growth rate from 2015 to 2030. The new simulated Ce demand would require supply beyond that produced in China. Finally, we illustrate revenue streams for different ore compositions in China in 2015.

  19. Using supply chain management to enable GIS units to improve their response to their customers' needs

    CSIR Research Space (South Africa)

    Schmitz, Peter MU

    2008-09-01

    Full Text Available (2000) also indicated that there will be several management tools available to assist GIS units to enable them to manage themselves successfully. This paper discusses such a management tool, namely supply chain management. Supply chain management is used...

  20. Growth Responses of Plantago major L. ssp. pleiosperma (Pilger) to Changes in Mineral Supply : Evidence for Regulation by Cytokinins.

    Science.gov (United States)

    Kuiper, D

    1988-07-01

    Plants of an inbred line of Plantago major ssp. pleiosperma were subjected to an alteration in mineral supply. Observed responses of growth rate and shoot to root ratio are thought to be induced by changes in endogenous cytokinin concentration and not by mineral concentration in plant tissue.

  1. Demand Intensity, Market Parameters and Policy Responses towards Demand and Supply of Private Supplementary Tutoring in China

    Science.gov (United States)

    Kwok, Percy Lai Yin

    2010-01-01

    Based on some longitudinal studies of private tutoring in twelve cities, towns, municipalities and provinces of China, the paper endeavours to depict demand intensity, articulate market parameters and reflect on policy responses towards the demand-supply mechanism of the vast shadowy educational phenomena at primary and secondary levels. Such…

  2. Contractual Control in the Supply Chain. On Corporate Social Responsibility, Codes of Conduct, Contracts and (Avoiding) Liability

    NARCIS (Netherlands)

    Vytopil, A.L.

    2015-01-01

    This research addresses a number of questions that have been raised in the wake of the Rana Plaza factory collapse. It focuses on the extent of the legal responsibility and liability for CSR violations in the supply chains of MNCs in the Netherlands, England and California (United States). Many MNCs

  3. Comparison of the trace metal concentration of drinking water supply options in southwest coastal areas of Bangladesh

    Science.gov (United States)

    Islam, Md. Atikul; Karim, Md. Rezaul; Higuchi, Takaya; Sakakibara, Hiroyuki; Sekine, Masahiko

    2014-06-01

    In the coastal areas of Bangladesh, scarcity of drinking water is acute as the fresh water aquifers at reasonable depths are not available and surface water is highly saline. Households are mainly dependent on rainwater harvesting, pond sand filter (PSF), and rain-fed pond water for drinking purposes. To ascertain the water quality for human consumption, chemical parameters such as pH, conductivity and the concentrations of calcium, magnesium, iron, manganese, copper, zinc, lead, chromium, cadmium, nickel and arsenic were evaluated in the alternative drinking water supply options employed in the southwest coastal areas of Bangladesh. An inductively coupled plasma-optical emission spectroscopy was used for determination of trace metal concentrations. pH and conductivity were measured using HANNA Instrument. The mean iron and manganese concentrations for rain-fed pond and PSF water were much higher than harvested rainwater. The iron concentrations for 41 % of the pond water samples were higher than the Bangladesh guideline value. Iron and manganese removal by PSFs was found to be 74 and 51 %, respectively. Scarcity of calcium and magnesium were found in harvested rainwater. Furthermore, one pond water sample showed arsenic concentration above the 10 μg/l WHO drinking water guideline. The presence of an elevated iron and manganese and low calcium and magnesium concentrations in the drinking water could be a matter of public health concern.

  4. Economisation of the Education System in Shrinking Regions? The Demographic Responsiveness of Education Demand and Supply at Different Levels of the Education System

    National Research Council Canada - National Science Library

    Dr. Walter Bartl

    2013-01-01

    .... These strategies are, however, not always (directly) attributable to demographic decline. Moreover, there is considerable variation in the demographic responsiveness of education demand and supply...

  5. A novel dithiourea and its response to metal ions

    Institute of Scientific and Technical Information of China (English)

    Lu Yuan; Hong Zhong; Li Oing Li; Jing Jing Xiao

    2012-01-01

    The synthesis,characterization,and its response to metal ions of a novel thiourea N,N'-diethoxycarbonyl-N'',N'''-(1,2-ethylidene) dithiourea was reported.The results show that this dithiourea with new structure can react with Cu2+ and Ni2+ separately,and has a best selectivity to Fe3+ ions.Bench-scale flotation tests were also carried out,verifying it has higher copper flotation recovery and better selectivity to sulfide ores containing Cu compared with universal collectors.

  6. Study of the stability of electrode metal melting and transfer in the process of consumable electrode welding powered by supplies with differing dynamic characteristics

    Science.gov (United States)

    Saraev, Y. N.; Chinakhov, D. A.; Il'yashchenko, D. P.; Kiselev, A. S.; Gardiner, A. S.; Raev, I. V.

    2016-11-01

    In the paper we present the results of the study of the power supply characteristics effect upon the stability of electrode metal melting and transfer into the weld pool in the process of consumable electrode welding. It was shown that application of inverter type welding power supplies of the new generation results in changing the characteristics of the heat and mass transfer which has a decisive impact upon the heat content of the weld pool, reduction of residual stresses in the heat-affected zone (HAZ). The authors also substantiate the tendency to the reduction of the structural constituents in the area of the permanent joint.

  7. Smart responsive microcapsules capable of recognizing heavy metal ions.

    Science.gov (United States)

    Pi, Shuo-Wei; Ju, Xiao-Jie; Wu, Han-Guang; Xie, Rui; Chu, Liang-Yin

    2010-09-15

    Smart responsive microcapsules capable of recognizing heavy metal ions are successfully prepared with oil-in-water-in-oil double emulsions as templates for polymerization in this study. The microcapsules are featured with thin poly(N-isopropylacrylamide-co-benzo-18-crown-6-acrylamide) (P(NIPAM-co-BCAm)) membranes, and they can selectively recognize special heavy metal ions such as barium(II) or lead(II) ions very well due to the "host-guest" complexation between the BCAm receptors and barium(II) or lead(II) ions. The stable BCAm/Ba(2+) or BCAm/Pb(2+) complexes in the P(NIPAM-co-BCAm) membrane cause a positive shift of the volume phase transition temperature of the crosslinked P(NIPAM-co-BCAm) hydrogel to a higher temperature, and the repulsion among the charged BCAm/Ba(2+) or BCAm/Pb(2+) complexes and the osmotic pressure within the P(NIPAM-co-BCAm) membranes result in the swelling of microcapsules. Induced by recognizing barium(II) or lead(II) ions, the prepared microcapsules with P(NIPAM-co-BCAm) membranes exhibit isothermal and significant swelling not only in outer and inner diameters but also in the membrane thickness. The proposed microcapsules in this study are highly attractive for developing smart sensors and/or carriers for detection and/or elimination of heavy metal ions.

  8. Layerless Manufacturing & SAP - Creating Responsive Shop Floor in the Supply Chain

    Directory of Open Access Journals (Sweden)

    Dr.S. Muthu

    2010-04-01

    Full Text Available This paper shall explore the fundamental science behind the ever changing global supply chain. An analogous view of supply chain evolution to that of organic survival theory yields philosophies andmethods for achieving strategic advantage and tactical superiority. Manufacturing execution systems (MES are helping manufacturers bridge the gaps between the shop floor, the supply chain and the ERPsystem. By doing this, these systems are giving manufacturers more visibility and the control they need to make their production rocesses more efficient. Many businesses find it difficult to trulymaximize Supply Chain or Manufacturing efficiency from back office to mobile worker and maintain real time visibility of what happens on the shop floor. We have successfully implemented true real-time mobileintegration for major production sites across globe. SAP investment by reducing critical errors and enhancing customer service. We utilize standard Windows interfaces and WLAN technology to makeit easy for shop floor personnel to interact with SAP in real time, using standard automation system.

  9. Ultrafast response sensor to formaldehyde gas based on metal oxide.

    Science.gov (United States)

    Choi, N-J; Lee, H-K; Moon, S E; Kim, J; Yang, W S

    2014-08-01

    Thick film semiconductor gas sensors based on indium oxide were fabricated on Si substrate. The sensing materials on Si substrate were characterized using optical microscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM), and so on. They were very fine and uniform and we found out that particle sizes were about 20~30 nm through XRD analysis. Gas responses of fabricated sensors were measured in a chamber where gas flow was controlled by mass flow controller (MFC). Their resistance changes were monitored in real time by using data acquisition board and personal computer. Gas response characteristics were examined for formaldehyde (HCHO) gas which was known as the cause of sick building syndrome. Particularly, the sensors showed responses to formaldehyde gas at sub ppm (cf, standard of natural environment in building is about 80 ppb by ministry of environment in Korea), as a function of operating temperatures and gas concentrations. Also, we investigated sensitivity, repetition, selectivity, response speed and reproducibility of the sensors. The lowest detection limit is HCHO 25 ppb and sensitivity at 800 ppb is over 25% at 350 °C operating temperature. The response time (8 s) and recovery time (15 s) to HCHO gas at 200 ppb were very fast compared to other commercial products in flow type measurement condition. Repetition measurement was very good with ±3% in full measurement range. The fabricated metal oxide gas sensor showed good performance to HCHO gas and proved that it could be adaptable to indoor environment in building.

  10. Comparative growth, dry matter accumulation and photosynthetic rate of seven species of Eucalypt in response to phosphorus supply

    Institute of Scientific and Technical Information of China (English)

    Peng-fei Wu; Xiang-qing Ma; Mulualem Tigabu; Yong Huang; Li-li Zhou; Liping Cai; Xiao-long Hou; Per Christer Oden

    2014-01-01

    Plantations of eucalypts as short-rotation tree crops are rapidly expanding in tropical and sub-tropical regions, including southern China, where the soils are acidic and available phosphorus (P) is limited. We investigated seedling growth, dry matter accumulation, and the dynamics of photosynthetic rate and chlorophyll content of seven Eucalyptus spe-cies/hybrids (E. dunnii, E. grandis, E. grandis × E. camaldulensis, E. urophylla × E. camaldulensis, E. urophylla × E. tereticornis, E. grandis × E. tereticornis, E. urophylla × E. grandis) in response to different levels of P supply (0, 6, 12 and 18 mg⋅kg-1 KH2PO4). The photosynthetic rate and the chlorophyll content significantly declined as the P supply declined in almost a linear fashion for all species as the P stress period extended. In the absence of P supply, height growth of seedlings of all species was significantly impaired, while root collar diameter growth and whole plant dry matter accumulation was not affected by the level of P supply in most of the species. Significant inter-species variations in growth, dry matter accumulation and photosynthetic rate in response to P supply were detected. Eucalyptus dunnii had the lowest growth perform-ance across all levels of P supply while E. urophylla × E. tereticornis showed superior growth performance. From a practical point of view, E. urophylla × E. tereticornis is suggested as a candidate hybrid for planting on slightly P-deficient sites in southern China while E. dunnii, being a slow-growing species, is not suitable for short-rotation plantation. On plantation sites where severe P deficiency exists, P fertilization needs to be considered to boost rapid growth of seedlings so as to meet the man-agement objectives of short-rotation plantation.

  11. Responses of plant growth rate to nitrogen supply: a comparison of relative addition and N interruption treatments.

    Science.gov (United States)

    Walker, R L; Burns, I G; Moorby, J

    2001-02-01

    This paper investigates the effects of uptake of nitrate and the availability of internal N reserves on growth rate in times of restricted supply, and examines the extent to which the response is mediated by the different pools of N (nitrate N, organic N and total N) in the plant. Hydroponic experiments were carried out with young lettuce plants (Lactuca sativa L.) to compare responses to either an interruption in external N supply or the imposition of different relative N addition rate (RAR) treatments. The resulting relationships between whole plant relative growth rate (RGR) and N concentration varied between linear and curvilinear (or possibly bi-linear) forms depending on the treatment conditions. The relationship was curvilinear when the external N supply was interrupted, but linear when N was supplied by either RAR methods or as a supra-optimal external N supply. These differences resulted from the ability of the plant to use external sources of N more readily than their internal N reserves. These results show that when sub-optimal sources of external N were available, RGR was maintained at a rate which was dependent on the rate of nitrate uptake by the roots. Newly acquired N was channelled directly to the sites of highest demand, where it was assimilated rapidly. As a result, nitrate only tended to accumulate in plant tissues when its supply was essentially adequate. By comparison, plants forced to rely solely on their internal reserves were never able to mobilize and redistribute N between tissues quickly enough to prevent reductions in growth rate as their tissue N reserves declined. Evidence is presented to show that the rate of remobilization of N depends on the size and type of the N pools within the plant, and that changes in their rates of remobilization and/or transfer between pools are the main factors influencing the form of the relationship between RGR and N concentration.

  12. Beryllium Metal Supply Options

    Science.gov (United States)

    1989-01-01

    44124P 0.& Box 909 Piscataway, NJ 00015-1 ME MBERS Dr. Norbrert S. Baer Dr Melvin F. Kanninen Dr. William P. SliclsterHagriop Kevorkian Professur of...34potential" exposure, perhaps 20 percent, should be used to estimate "actual" exposure when respiratory protection is required. However, the jobs requiring...of the full-time process operator. Similarly, they are not directly applicable to workers, such as super- visors, whose job may take them through se

  13. Effective Dielectric Response of Nonlinear Composites of Coated Metal Inclusions

    Institute of Scientific and Technical Information of China (English)

    CHEN Guo-Qing; WU Ya-Min

    2007-01-01

    The effective dielectric response of the composites in which nondilute coated metal particles are randomly embedded in a linear host is investigated. Two types of coated particles are considered, one is that the core is nonlinear, the other is that the shell is nonlinear. We derive general expressions for the effective linear dielectric function and the effective third-order nonlinear susceptibility, and take one step forward to perform numerical calculations on the coated metal/dielectric composites. Numerical results show that the effective linear and nonlinear dielectric responses can be greatly enhanced near the surface plasmon resonant frequency. Moreover, the resonant peaks are found within a range from 0.46ωp to 0.57ωp for spherical particles and from 0.59ωp to 0.7ωp for cylindrical inclusions. In the frequency region, the resonant peak can achieve the maximum, according to an optimal structural parameter and volume fraction. The resonant frequency exhibits a redshift with the increasing structural parameter k or volume fraction f or dimensionality factor D.

  14. Weldability of thin sheet metals by small-scale resistance spot welding using high-frequency inverter and capacitor-discharge power supplies

    Science.gov (United States)

    Zhou, Y.; Dong, S. J.; Ely, K. J.

    2001-08-01

    An investigation has been conducted of the weldability of 0.2-mm-thick sheet aluminum, brass, and copper in small-scale resistance spot welding using a high-frequency inverter and a capacitor-discharge power supply. The results have been compared to those of previous investigations using a line-frequency alternating current power supply. The effects of electrode materials and process parameters on joint strength, nugget diameter, weld-metal expulsion and electrode-sheet sticking were studied. This work has also provided practical guidelines for selection of power supplies, process parameters (welding current/pulse energy, welding time/pulse width, electrode forces, etc.) and electrode materials for small-scale resistance spot welding of thin sheet aluminum, brass and copper.

  15. Assessment of a mussel as a metal bioindicator of coastal contamination: Relationships between metal bioaccumulation and multiple biomarker responses

    Energy Technology Data Exchange (ETDEWEB)

    Chandurvelan, Rathishri, E-mail: rch118@uclive.ac.nz [School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140 (New Zealand); Marsden, Islay D., E-mail: islay.marsden@canterbury.ac.nz [School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140 (New Zealand); Glover, Chris N., E-mail: chris.glover@canterbury.ac.nz [School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140 (New Zealand); Gaw, Sally, E-mail: sally.gaw@canterbury.ac.nz [Department of Chemistry, University of Canterbury, Private Bag 4800, Christchurch 8140 (New Zealand)

    2015-04-01

    This is the first study to use a multiple biomarker approach on the green-lipped mussel, Perna canaliculus to test its feasibility as a bioindicator of coastal metal contamination in New Zealand (NZ). Mussels were collected from six low intertidal sites varying in terms of anthropogenic impacts, within two regions (West Coast and Nelson) of the South Island of NZ. Trace elements, including arsenic (As), cadmium (Cd), copper (Cu), lead (Pb), nickel (Ni), and zinc (Zn), were measured in the gills, digestive gland, foot and mantle, and in the surface sediments from where mussels were collected. Metal levels in the sediment were relatively low and there was only one site (Mapua, Nelson) where a metal (Ni) exceeded the Australian and New Zealand Interim Sediment Quality Guideline values. Metal levels in the digestive gland were generally higher than those from the other tissues. A variety of biomarkers were assessed to ascertain mussel health. Clearance rate, a physiological endpoint, correlated with metal level in the tissues, and along with scope for growth, was reduced in the most contaminated site. Metallothionein-like protein content and catalase activity in the digestive gland, and catalase activity and lipid peroxidation in the gill, were also correlated to metal accumulation. Although there were few regional differences, the sampling sites were clearly distinguishable based on the metal contamination profiles and biomarker responses. P. canaliculus appears to be a useful bioindicator species for coastal habitats subject to metal contamination. In this study tissue and whole organism responses provided insight into the biological stress responses of mussels to metal contaminants, indicating that such measurements could be a useful addition to biomonitoring programmes in NZ. - Highlights: • Multiple biomarker responses were measured in mussels from 6 sites. • Metal content of mussel tissues correlated with specific biomarker responses. • Clearance rate

  16. Regional probabilistic risk assessment of heavy metals in different environmental media and land uses: An urbanization-affected drinking water supply area

    Science.gov (United States)

    Peng, Chi; Cai, Yimin; Wang, Tieyu; Xiao, Rongbo; Chen, Weiping

    2016-11-01

    In this study, we proposed a Regional Probabilistic Risk Assessment (RPRA) to estimate the health risks of exposing residents to heavy metals in different environmental media and land uses. The mean and ranges of heavy metal concentrations were measured in water, sediments, soil profiles and surface soils under four land uses along the Shunde Waterway, a drinking water supply area in China. Hazard quotients (HQs) were estimated for various exposure routes and heavy metal species. Riverbank vegetable plots and private vegetable plots had 95th percentiles of total HQs greater than 3 and 1, respectively, indicating high risks of cultivation on the flooded riverbank. Vegetable uptake and leaching to groundwater were the two transfer routes of soil metals causing high health risks. Exposure risks during outdoor recreation, farming and swimming along the Shunde Waterway are theoretically safe. Arsenic and cadmium were identified as the priority pollutants that contribute the most risk among the heavy metals. Sensitivity analysis showed that the exposure route, variations in exposure parameters, mobility of heavy metals in soil, and metal concentrations all influenced the risk estimates.

  17. Stomatal- and growth responses in willow to deficits in water- and nitrogen supply. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Stadenberg, I. [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dep. for Production Ecology

    2002-02-01

    The two plants, grown with an [N] of 100 mg per litre and subjected to a decrease in N-supply decreased their leaf relative growth rate from 22% per day to 13% per day within 2 days. Stomatal conductance did not change significantly after the decrease in N-supply. Xylem samples did not show any significant changes in its composition of mineral nutrient elements after decreased N-supply. The three plants, grown with an [N] of 50 mg per litre and subjected to a decrease in N-supply, significantly decreased leaf relative growth rate from 18.5 % to 9 % per day within 2 days. Stomatal conductance did not change significantly after the decrease in N-supply. Xylem sap samples showed a significant decrease in [K] (74 mg/l to 42 mg/l) and [S] (11 mg/l to 3.2 mg/l) within 2 days after decreased N-supply. The four plants subjected to root drying decreased their leaf relative growth rate slightly but not significantly during the drying period. Xylem samples showed a significant decrease in S-concentration (11 mg/l to 1.3 mg/l) and [NO{sub 3}] (8.0 mg/l to 1.0 mg/l), while [Fe] increased significantly (0.065 mg/l to 0.14 mg/l). Stomatal conductance is known to decrease when plants are subjected to drying of part of the root system. This was shown for Salix dasyclados in a recent publication.

  18. Design of Multi-agent Supply Chain System to Support Quick Response in Textile-Apparel Industry

    Institute of Scientific and Technical Information of China (English)

    XU Qi

    2007-01-01

    Owing to the fast growth of global market, textileand apparel industries which are a typical seasonal businessare facing crucial challenges from both competitors andconsumers. In order to get survived, forming supply chainand utilizing the emerged technology to establish a quickresponse system become an important common practice forenterprises in terms of cost reduction and efficiencyimprovement. This paper presents a multi-ageat-basedintegrated framework for quick response in textile andapparel supply chain. By sharing information andcollaborating among chain partner, the multi-agent systemprovides a promising computing paradigm for quick responsebusiness processes. A prototype based on the proposedframework is implemented using ZEUS toolkit. It presentshow the proposed architecture is being designed to establishcollaborative business environment by providing dynamicquick response processes.

  19. Call-centre occupant response to new and used filters at two outdoor air supply rates

    DEFF Research Database (Denmark)

    Wargocki, Pawel; Wyon, David; Nielsen, J.;

    2002-01-01

    A 2x2 replicaterd field intervention experiment was conducted in a call-centre providing a public telephone directory service: outdoor air supply rate was 8% or 80% of the total airflow of 430 L/s providing 3.5 h-1; and the supply air filters were either new or used (i.e. used in place for 6 mont......). Each of these 4 conditions was maintained for a full working week at a time. Room temperature and humidity averaged 24 deg.C and 27% RH. The 26 operators were blind to conditions and assessed perceived air quality (PAQ), the intensity of Sick Building Syndrome (SBS) symnptoms and self...

  20. Development of a social auditing management system to measure responsibility in a supply chain : Case Company: Pramia

    OpenAIRE

    2012-01-01

    The purpose of this study was to develop an auditing system for a case company, Pramia, which would measure and manage responsibility throughout their supply chain. This was done by researching theoretical methodology in social auditing and key concepts related to the study and also a practical method used to gain insight on developing the management system. This thesis addresses the issues and needs of Pramia, provides a layout of actions for the revised management system, as well as a plan ...

  1. Volcanic ash supply to the surface ocean – remote sensing of biological responses and their wider biogeochemical significance

    Directory of Open Access Journals (Sweden)

    Thomas J. Browning

    2015-03-01

    Full Text Available Transient micronutrient enrichment of the surface ocean can enhance phytoplankton growth rates and alter microbial community structure with an ensuing spectrum of biogeochemical feedbacks. Strong phytoplankton responses to micronutrients supplied by volcanic ash have been reported recently. Here we: (i synthesize findings from these recent studies; (ii report the results of a new remote sensing study of ash fertilization; and (iii calculate theoretical bounds of ash-fertilized carbon export. Our synthesis highlights that phytoplankton responses to ash do not always simply mimic that of iron amendment; the exact mechanisms for this are likely biogeochemically important but are not yet well understood. Inherent optical properties of ash-loaded seawater suggest rhyolitic ash biases routine satellite chlorophyll-a estimation upwards by more than an order of magnitude for waters with 0.5 mg chlorophyll-a m-3. For this reason post-ash-deposition chlorophyll-a changes in oligotrophic waters detected via standard Case 1 (open ocean algorithms should be interpreted with caution. Remote sensing analysis of historic events with a bias less than a factor of 2 provided limited stand-alone evidence for ash-fertilization. Confounding factors were poor coverage, incoherent ash dispersal, and ambiguity ascribing biomass changes to ash supply over other potential drivers. Using current estimates of iron release and carbon export efficiencies, uncertainty bounds of ash-fertilized carbon export for 3 events are presented. Patagonian iron supply to the Southern Ocean from volcanic eruptions is less than that of windblown dust on thousand year timescales but can dominate supply at shorter timescales. Reducing uncertainties in remote sensing of phytoplankton response and nutrient release from ash are avenues for enabling assessment of the oceanic response to large-scale transient nutrient enrichment.

  2. Metabolomic Investigation of the Bacterial Response to a Metal Challenge▿

    Science.gov (United States)

    Tremaroli, Valentina; Workentine, Matthew L.; Weljie, Aalim M.; Vogel, Hans J.; Ceri, Howard; Viti, Carlo; Tatti, Enrico; Zhang, Ping; Hynes, Alexander P.; Turner, Raymond J.; Zannoni, Davide

    2009-01-01

    Pseudomonas pseudoalcaligenes KF707 is naturally resistant to the toxic metalloid tellurite, but the mechanisms of resistance are not known. In this study we report the isolation of a KF707 mutant (T5) with hyperresistance to tellurite. In order to characterize the bacterial response and the pathways leading to tolerance, we utilized Phenotype MicroArray technology (Biolog) and a metabolomic technique based on nuclear magnetic resonance spectroscopy. The physiological states of KF707 wild-type and T5 cells exposed to tellurite were also compared in terms of viability and reduced thiol content. Our analyses showed an extensive change in metabolism upon the addition of tellurite to KF707 cultures as well as different responses when the wild-type and T5 strains were compared. Even in the absence of tellurite, T5 cells displayed a “poised” physiological status, primed for tellurite exposure and characterized by altered intracellular levels of glutathione, branched-chain amino acids, and betaine, along with increased resistance to other toxic metals and metabolic inhibitors. We conclude that hyperresistance to tellurite in P. pseudoalcaligenes KF707 is correlated with the induction of the oxidative stress response, resistance to membrane perturbation, and reconfiguration of cellular metabolism. PMID:19047385

  3. Metabolomic investigation of the bacterial response to a metal challenge.

    Science.gov (United States)

    Tremaroli, Valentina; Workentine, Matthew L; Weljie, Aalim M; Vogel, Hans J; Ceri, Howard; Viti, Carlo; Tatti, Enrico; Zhang, Ping; Hynes, Alexander P; Turner, Raymond J; Zannoni, Davide

    2009-02-01

    Pseudomonas pseudoalcaligenes KF707 is naturally resistant to the toxic metalloid tellurite, but the mechanisms of resistance are not known. In this study we report the isolation of a KF707 mutant (T5) with hyperresistance to tellurite. In order to characterize the bacterial response and the pathways leading to tolerance, we utilized Phenotype MicroArray technology (Biolog) and a metabolomic technique based on nuclear magnetic resonance spectroscopy. The physiological states of KF707 wild-type and T5 cells exposed to tellurite were also compared in terms of viability and reduced thiol content. Our analyses showed an extensive change in metabolism upon the addition of tellurite to KF707 cultures as well as different responses when the wild-type and T5 strains were compared. Even in the absence of tellurite, T5 cells displayed a "poised" physiological status, primed for tellurite exposure and characterized by altered intracellular levels of glutathione, branched-chain amino acids, and betaine, along with increased resistance to other toxic metals and metabolic inhibitors. We conclude that hyperresistance to tellurite in P. pseudoalcaligenes KF707 is correlated with the induction of the oxidative stress response, resistance to membrane perturbation, and reconfiguration of cellular metabolism.

  4. Biological response to millennial variability of dust and nutrient supply in the Subantarctic South Atlantic Ocean.

    Science.gov (United States)

    Anderson, Robert F; Barker, Stephen; Fleisher, Martin; Gersonde, Rainer; Goldstein, Steven L; Kuhn, Gerhard; Mortyn, P Graham; Pahnke, Katharina; Sachs, Julian P

    2014-07-13

    Fluxes of lithogenic material and fluxes of three palaeo-productivity proxies (organic carbon, biogenic opal and alkenones) over the past 100,000 years were determined using the (230)Th-normalization method in three sediment cores from the Subantarctic South Atlantic Ocean. Features in the lithogenic flux record of each core correspond to similar features in the record of dust deposition in the EPICA Dome C ice core. Biogenic fluxes correlate with lithogenic fluxes in each sediment core. Our preferred interpretation is that South American dust, most probably from Patagonia, constitutes a major source of lithogenic material in Subantarctic South Atlantic sediments, and that past biological productivity in this region responded to variability in the supply of dust, probably due to biologically available iron carried by the dust. Greater nutrient supply as well as greater nutrient utilization (stimulated by dust) contributed to Subantarctic productivity during cold periods, in contrast to the region south of the Antarctic Polar Front (APF), where reduced nutrient supply during cold periods was the principal factor limiting productivity. The anti-phased patterns of productivity on opposite sides of the APF point to shifts in the physical supply of nutrients and to dust as cofactors regulating productivity in the Southern Ocean. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  5. Responsible Management and Use of a Personal Take-Home Naloxone Supply: A Pilot Project

    Science.gov (United States)

    McAuley, Andrew; Lindsay, George; Woods, Maureen; Louttit, Derek

    2010-01-01

    Aims: To assess if Scottish drug users, their family and friends could be trained in critical incident management and the safe and effective administration of naloxone. The project also sought to monitor whether drug users can manage their own personal take-home naloxone (THN) supply and use it appropriately in an emergency opiate overdose…

  6. GEMFLOW: A time dependent model to assess responses to natural gas supply crises

    Energy Technology Data Exchange (ETDEWEB)

    Szikszai, A., E-mail: andras.szikszai@ec.europa.eu [European Commission, JRC-Institute for Energy, Energy Security Unit, P.O. Box 2, 1755 ZG Petten (Netherlands); Monforti, F. [European Commission, JRC-Institute for Energy, Energy Security Unit, P.O. Box 2, 1755 ZG Petten (Netherlands)

    2011-09-15

    The January 2009 gas dispute, followed by the biggest gas supply crisis ever, called for significant changes at the community level. In line with other measures (e.g. a new regulation to ensure security of gas supply), a new tool is needed that will help decision-makers react properly in such a situation. Based on Monte-Carlo modeling principles, this new tool is being developed to take the first step towards a comprehensive model. This model could be of great support to common European efforts in order to assess the possible outcomes of a supply disruption beforehand and minimize losses during an emergency by finding the optimal distribution of flows. Naturally, the described model cannot serve at present as hydraulic software that is currently used by the national system operators, but it is able to draw significant conclusions from the European gas system's capabilities. - Highlights: > Use of storages at maximum in case of supply shortfall is not necessarily the best solution. > The ratio of withdrawal capacity to storage space is crucial in the withdrawal utilization. > Combination of reverse flows and storages affects the success of disruption management. > Definition of lowest consumption level is inevitable for appropriate disruption management.

  7. Modeling plan-form deltaic response to changes in fluvial sediment supply

    NARCIS (Netherlands)

    Nienhuis, J.H.; Ashton, A.D.; Roos, P.C.; Hulscher, S.J.M.H.; Giosan, L.; Kranenburg, W.M.; Horstman, E.M.; Wijnberg, K.M.

    2012-01-01

    This study focuses on the effects of changes in fluvial sediment supply on the plan-form shape of wave-dominated deltas. We apply a one-line numerical shoreline model to calculate shoreline evolution after (I) elimination and (II) time-periodic variation of fluvial input. Model results suggest four

  8. Proliferation of maize (Zea mays L.) roots in response to localized supply of nitrate

    Science.gov (United States)

    Granato, T. C.; Raper, C. D. Jr; Raper CD, J. r. (Principal Investigator)

    1989-01-01

    Maize (Zea mays L.) plants with two primary nodal root axes were grown for 8 d in flowing nutrient culture with each axis independently supplied with NO3-. Dry matter accumulation by roots was similar whether 1.0 mol m-3 NO3- was supplied to one or both axes. When NO3- was supplied to only one axis, however, accumulation of dry matter within the root system was significantly greater in the axis supplied with NO3-. The increased dry matter accumulation by the +N-treated axis was attributable entirely to increased density and growth of lateral branches and not to a difference in growth of the primary axis. Proliferation of lateral branches for the +N axis was associated with the capacity for in situ reduction and utilization of a portion of the absorbed NO3-, especially in the apical region where lateral primordia are initiated. Although reduced nitrogen was translocated to the -N axis, concentrations in the -N axis remained significantly lower than in the +N axis. The concentration of reduced nitrogen, as well as in vitro NO3- reductase activity, was greater in apical than in more basal regions of the +N axis. The enhanced proliferation of lateral branches in the +N axis was accompanied by an increase in total respiration rate of the axis. Part of the increased respiration was attributable to increased mass of roots. The specific respiration rate (micromoles CO2 evolved per hour per gram root dry weight) was also greater for the +N than for the -N axis. If respiration rate is taken as representative of sink demand, stimulation of initiation and growth of laterals by in situ utilization of a localized exogenous supply of NO3- establishes an increased sink demand through enhanced metabolic activity and the increased partitioning of assimilates to the +N axis responds to the difference in sink demand between +N and -N axes.

  9. Leaf Gas Exchange and Fluorescence of Two Winter Wheat Varieties in Response to Drought Stress and Nitrogen Supply

    Science.gov (United States)

    Wang, Xiubo; Wang, Lifang; Shangguan, Zhouping

    2016-01-01

    Water and nitrogen supply are the two primary factors limiting productivity of wheat (Triticum aestivum L.). In our study, two winter wheat varieties, Xinong 979 and large-spike wheat, were evaluated for their physiological responses to different levels of nitrogen and water status during their seedling stage grown in a phytotron. Our results indicated that drought stress greatly reduced the net photosynthetic rate (Pn), transpiration rate (E), and stomatal conductance (Gs), but with a greater increase in instantaneous water use efficiency (WUE). At the meantime, the nitrogen (N) supply improved photosynthetic efficiency under water deficit. Parameters inferred from chlorophyll a measurements, i.e., photochemical quenching coefficient (qP), the maximum photochemical efficiency (Fv/Fm), the quantum yield of photosystemII(ΦPSII), and the apparent photosynthetic electron transport rate (ETR) decreased under water stress at all nitrogen levels and declined in N-deficient plants. The root–shoot ratio (R/S) increased slightly with water stress at a low N level; the smallest root–shoot ratio was found at a high N level and moderate drought stress treatment. These results suggest that an appropriate nitrogen supply may be necessary to enhance drought resistance in wheat by improving photosynthetic efficiency and relieving photoinhibition under drought stress. However, an excessive N supply had no effect on drought resistance, which even showed an adverse effect on plant growth. Comparing the two cultivars, Xinong 979 has a stronger drought resistance compared with large-spike wheat under N deficiency. PMID:27802318

  10. Collective Recycling Responsibility in Closed-Loop Fashion Supply Chains with a Third Party: Financial Sharing or Physical Sharing?

    Directory of Open Access Journals (Sweden)

    Jiajia Nie

    2013-01-01

    Full Text Available We develop three closed-loop supply chain models where manufacturers can utilize financial or physical support to push a third party to collect the used fashion product for remanufacturing. We first examine two strategies for the collective recycling responsibility (CRR, namely, the financial sharing (FS and the physical sharing (PS, using the model with no CRR as a benchmark. After that, we conduct a detailed comparison among the three models in terms of the retail price, demand, return rate, and the profits received by the supply chain members. With this study, we find the following. (i The FS or PS support offered by the manufacturer to the third party will result in a lower retail price and a higher demand. (ii The optimal return rate with PS scheme is always higher than that without the CRR, and the one with FS scheme is at least as high as that without the CRR. (iii All the members in the closed-loop supply chain can always benefit from the CRR. In addition, (iv which scheme of the FS, PS, or no CRR is the best for the supply chain members will depend heavily on the transfer price of the used product.

  11. Supply-side response to declining heroin purity: fentanyl overdose episode in New Jersey.

    Science.gov (United States)

    Hempstead, Katherine; Yildirim, Emel O

    2014-06-01

    The inelastic price demand observations characteristic of illegal drug markets have led to the conclusion that the burden of a negative supply shock would be completely reflected to consumers. This paper argues that the increasing availability of prescription opioids may threaten heroin sellers' profit margin and force them to find alternative methods to compensate buyers in the event of a supply shock. We investigate the 2006 fentanyl overdose episode in New Jersey and argue that the introduction of non-pharmaceutical fentanyl, its spatial distribution, and the timing of overdose deaths may have been related to trends in heroin purity. Using medical examiner data, as well as data from the Drug Enforcement Administration, Office of Diversion Control on retail sales of prescription opioids in a negative binomial specification, we show that month-to-month fluctuations in heroin purity have a significant effect on fentanyl-related overdoses, particularly in those areas where prescription opioids are highly available.

  12. Responsive metal/polymer nanocomposites via photothermal effect

    Science.gov (United States)

    Seyhan, Merve; Rende, Deniz; Huang, Liping; Malta, Seyda; Ozisik, Rahmi; Baysal, Nihat

    2013-03-01

    Metal nanoparticles can efficiently generate heat when exposed to electromagnetic radiation. The amount of heat generated and the temperature increase depends on the number of nanoparticles and their shape. In the current work, gold nanoparticles (AuNPs) were used as heat sources within polyethylene oxide (600,000 g/mol) via the photothermal effect. AuNPs were synthesized through Frens method, and were characterized using TEM. A laser source with a wavelength of 532 nm was used to heat AuNPs. Raman spectroscopy data showed that irradiation of AuNPs led to increasing temperature profiles in the vicinity of AuNPs, which is a result of the surface plasmon resonance. This property of AuNPs would enable the control of viscoelastic response of the polymer by altering crystallinity and temperature of the polymer matrix, thereby, providing responsive materials. This work is partially supported by NSF CMMI-1200270 and DUE-1003574. MS was supported by TUBITAK 2214 grant. NB was supported by TUBITAK 2219 grant.

  13. Beyond Symbolic Responses to Private Politics: Examining Labor Standards Improvement in Global Supply Chains

    OpenAIRE

    2016-01-01

    Worker rights advocates seeking to improve labor conditions in global supply chains have engaged in private political strategies prompting transnational corporations (TNCs) to adopt codes of conduct and monitor their suppliers for compliance, but it is not clear whether organizational structures established by TNCs to protect their reputations can actually raise labor standards. We extend the literature on private politics and organizational self-regulation by identifying several conditions u...

  14. Correlation clusters in the accumulation of metals in human scalp hair: effects of age, community of residence, and abundances of metals in air and water supplies.

    Science.gov (United States)

    Moon, J; Davison, A J; Smith, T J; Fadl, S

    1988-06-15

    Scalp hair samples taken from 122 children and 27 adults from three native Indian villages in northern Alberta, Canada were analyzed for 32 metals, in an attempt to trace industrial pollution into the human population. One of the villages has been exposed since 1967 to increased levels of several metals due to its proximity to the world's first two oil sands petroleum extraction plants (Suncor and Syncrude), which release large amounts of metals into the environment. Metal-enriched particulates are emitted at a rate of 547-780 kg h-1 for Suncor, and 713-1067 kg h-1 for Syncrude. To test the hypothesis that hair content reflected accumulation of environmental metals, water and aerometric samples were collected and analyzed for their metal content. These analyses demonstrated that elevated levels of nine metals in hair from children in one of the control villages (Garden River) are (with the exception of Al) correlated with increased levels of metals in water and air. Moreover, increased levels of Cu, but lowest levels of all other metals were found in hair and environmental samples from one control village (Fort Chipewyan). Correlation matrices for metals in the hair samples revealed three sets of highly intercorrelated metals ('correlation clusters'): (i) Pb/Cd; (ii) Al/V/Fe; (iii) Ca/Mg/Sr/Ba. These groups of metals were significantly intercorrelated (r greater than 0.6, p less than 0.001) in the total population, and in both children and adults, or both males and females, as well as when the population was compared according to community of residence. The robustness of the clusters is particularly noteworthy in view of large differences in the proportions and absolute amounts of the various metals in hair from children in the three villages. Plots of metal levels in hair as a function of age of subject reveal a dramatic decrease in concentrations of Al, V, and Fe during the first years of life. The high levels of Al and V in hair from very young children may

  15. Taxonomic and functional composition of the algal benthos exhibits similar successional trends in response to nutrient supply and current velocity.

    Science.gov (United States)

    Larson, Chad A; Passy, Sophia I; Laanbroek, Riks

    2012-05-01

    In an effort to identify the causes and patterns of temporal change in periphytic communities, we examined biomass accumulation, taxonomic and functional composition, rate of species turnover, and pairwise species correlations in response to variability in current velocity and nutrient supply in artificial stream flumes. Divergent patterns in community growth and succession were observed between nutrient treatments and, to a lesser extent, between flow treatments best described by shifts in taxonomic and functional composition. Specifically, understory low profile species, tolerant to low resource supply, became dominant under low nutrients, while overstory high profile and motile species with higher nutrient demands dominated the high nutrient treatments. Increased resource supply or current velocity did not influence the species turnover rate, measured by a time-lag analysis. Interspecific interactions, especially competition, did not appear to be driving community dynamics, as the number of positive and negative pairwise species correlations ranged between low and extremely low, respectively. The overwhelming majority of correlations were not significant, indicating that species within the biofilm matrix were not perceptibly influencing one another. Thus, temporal trends in taxonomic and functional composition were largely environmentally driven, signifying that coexistence in biofilms is defined by the same mechanism along the hierarchy from species to functional groups.

  16. Time-dependent current-density-functional theory for the metallic response of solids

    NARCIS (Netherlands)

    Romaniello, P; de Boeij, PL

    2005-01-01

    We extend the formulation of time-dependent current-density-functional theory for the linear response properties of dielectric and semi-metallic solids [Kootstra , J. Chem. Phys. 112, 6517 (2000)] to treat metals as well. To achieve this, the Kohn-Sham response functions have to include both interba

  17. Time-dependent current-density-functional theory for the metallic response of solids

    NARCIS (Netherlands)

    Romaniello, P; de Boeij, PL

    We extend the formulation of time-dependent current-density-functional theory for the linear response properties of dielectric and semi-metallic solids [Kootstra , J. Chem. Phys. 112, 6517 (2000)] to treat metals as well. To achieve this, the Kohn-Sham response functions have to include both

  18. Social Responsibility in Tobacco Production? Tobacco Companies Use of Green Supply Chains to Obscure the Real Costs of Tobacco Farming

    Science.gov (United States)

    Otañez, Marty

    2011-01-01

    Background Tobacco companies have come under increased criticism because of environmental and labor practices related to growing tobacco in developing countries. Methods Analysis of tobacco industry documents, industry web sites and interviews with tobacco farmers in Tanzania and tobacco farm workers, farm authorities, trade unionists, government officials and corporate executives from global tobacco leaf companies in Malawi. Results British American Tobacco and Philip Morris created supply chains in the 1990s to improve production efficiency, control, access to markets, and profits. In the 2000s, the companies used their supply chains in an attempt to legitimize their portrayals of tobacco farming as socially and environmentally friendly, rather than take meaningful steps to eliminate child labor and reduce deforestation in developing countries. The tobacco companies used nominal self-evaluation (not truly independent evaluators) and public relations to create the impression of social responsibility. The companies benefit from $1.2 billion in unpaid labor costs due to child labor and more than $64 million annually in costs that would have been made to avoid tobacco related deforestation in the top twelve tobacco growing developing countries, far exceeding the money they spend nominally working to change these practices. Conclusions The tobacco industry uses green supply chains to make tobacco farming in developing countries appear sustainable while continuing to purchase leaf produced with child labor and high rates of deforestation. Strategies to counter green supply chain schemes include securing implementing protocols for the WHO Framework Convention on Tobacco Control to regulate the companies’ practices at the farm level. PMID:21504915

  19. Corporate Social Responsibility in Buyer-Supplier Relationships: Is it Beneficial for Top-Tier Suppliers to Market their Capability to Ensure a Responsible Supply Chain?

    Directory of Open Access Journals (Sweden)

    Thomas Leppelt

    2013-11-01

    Full Text Available This study assesses how top-tier suppliers market their capabilities to ensure a responsible upstream supply chain to their downstream buyers, and how the marketing of corporate social responsibility (CSR-related supply management practices affects the reputation of top-tier suppliers in business-to-business (B2B markets. In a cross-functional multiple-case study involving marketing, purchasing, and sustainability executives of five supplier organizations in Central Europe, we explored four distinct approaches for marketing superior CSR management abilities in B2B markets that potentially foster long-term comparative advantages: (1 Fact-based communication of measurable CSR capabilities, (2 targeting of indirect customers and influencers, (3 marketing through education, and (4 marketing of CSR as a service. Moreover, our inductive results provide evidence that the effective marketing of CSR capabilities enhances a supplier’s reputation only if it sends consistent signals to the market. Therefore, a close integration of marketing and purchasing is crucial for achieving signaling consistency. Building on an established framework of purchasing-marketing integration in the particular context of CSR we developed a crossfunctional theory on the link between marketing, supply chain alignment and reputation, which is expressed in four sets of testable research propositions.

  20. Toxic metal accumulation, responses to exposure and mechanisms of tolerance in plants.

    Science.gov (United States)

    Clemens, S

    2006-11-01

    Over the past 200 years emissions of toxic heavy metals have risen tremendously and significantly exceed those from natural sources for practically all metals. Uptake and accumulation by crop plants represents the main entry pathway for potentially health-threatening toxic metals into human and animal food. Of major concern are the metalloids arsenic (As) and selenium (Se), and the metals cadmium (Cd), mercury (Hg), and lead (Pb). This review discusses the molecular mechanisms of toxic metal accumulation in plants and algae, the responses to metal exposure, as well as our understanding of metal tolerance and its evolution. The main emphasis will be on cadmium, which is by far the most widely studied of the non-essential toxic metals/metalloids. Entry via Zn2+, Fe2+, and Ca2+ transporters is the molecular basis of Cd2+ uptake into plant cells. Much less is known about the partitioning of non-essential metals and about the genes underlying the enormous diversity among plants with respect to Cd accumulation in different tissues. Numerous studies have described symptoms and responses of plants upon toxic metal exposure. Mysterious are primary targets of toxicity, the degree of specificity of responses, the sensing and the signaling events that lead to transcriptional activation. All plants apparently possess a basal tolerance of toxic non-essential metals. For Cd and As, this is largely dependent on the phytochelatin pathway. Not understood is the molecular biology of Cd hypertolerance in certain plant species such as the metallophytes Arabidopsis halleri or Thlaspi caerulescens.

  1. Quantitative modelling of the response of earthworms to metals

    NARCIS (Netherlands)

    Qiu, Hao

    2014-01-01

    Metals in soils can pose a serious threat to soil dwelling organisms, plants, and human beings. A major uncertainty in terrestrial ecological risk assessment for metals is the integrated effect of the physicochemical properties of soil on toxicity and how this allows for extrapolation of toxicity

  2. Food supply and demand, a simulation model of the functional response of grazing ruminants

    NARCIS (Netherlands)

    Smallegange, I.M.; Brunsting, A.M.H.

    2002-01-01

    A dynamic model of the functional response is a first prerequisite to be able to bridge the gap between local feeding ecology and grazing rules that pertain to larger scales. A mechanistic model is presented that simulates the functional response, growth and grazing time of ruminants. It is based on

  3. Food supply and demand, a simulation model of the functional response of grazing ruminants

    NARCIS (Netherlands)

    Smallegange, I.M.; Brunsting, A.M.H.

    2002-01-01

    A dynamic model of the functional response is a first prerequisite to be able to bridge the gap between local feeding ecology and grazing rules that pertain to larger scales. A mechanistic model is presented that simulates the functional response, growth and grazing time of ruminants. It is based on

  4. Sulfate supply influences compartment specific glutathione metabolism and confers enhanced resistance to Tobacco mosaic virus during a hypersensitive response

    Science.gov (United States)

    Király, Lóránt; Künstler, András; Höller, Kerstin; Fattinger, Maria; Juhász, Csilla; Müller, Maria; Gullner, Gábor; Zechmann, Bernd

    2012-01-01

    Sufficient sulfate supply has been linked to the development of sulfur induced resistance or sulfur enhanced defense (SIR/SED) in plants. In this study we investigated the effects of sulfate (S) supply on the response of genetically resistant tobacco (Nicotiana tabacum cv. Samsun NN) to Tobacco mosaic virus (TMV). Plants grown with sufficient sulfate (+S plants) developed significantly less necrotic lesions during a hypersensitive response (HR) when compared to plants grown without sulfate (−S plants). In +S plants reduced TMV accumulation was evident on the level of viral RNA. Enhanced virus resistance correlated with elevated levels of cysteine and glutathione and early induction of a Tau class glutathione S-transferase and a salicylic acid-binding catalase gene. These data indicate that the elevated antioxidant capacity of +S plants was able to reduce the effects of HR, leading to enhanced virus resistance. Expression of pathogenesis-related genes was also markedly up-regulated in +S plants after TMV-inoculation. On the subcellular level, comparison of TMV-inoculated +S and −S plants revealed that +S plants contained 55–132 % higher glutathione levels in mitochondria, chloroplasts, nuclei, peroxisomes and the cytosol than −S plants. Interestingly, mitochondria were the only organelles where TMV-inoculation resulted in a decrease of glutathione levels when compared to mock-inoculated plants. This was particularly obvious in −S plants, where the development of necrotic lesions was more pronounced. In summary, the overall higher antioxidative capacity and elevated activation of defense genes in +S plants indicate that sufficient sulfate supply enhances a preexisting plant defense reaction resulting in reduced symptom development and virus accumulation. PMID:22122784

  5. Responses of Niphargus montellianus and Gammarus balcanicus (Crustacea, Amphipoda) from karst waters to heavy metal exposure

    Science.gov (United States)

    Coppellotti Krupa, O.; Guidolin, L.

    2003-05-01

    The response to some heavy metals (Cd, Cu, and Zn) was examined in two amphipods, Niphargus montellianus and Gammarus balcanicus, living in karst waters and endowed with different ecological characteristics. Exposure experiments were made, in the controlled conditions of a biospeleology laboratory, to increasing concentrations of metals in the range 0.1 10 μg ml^{-1} for up to 10 days. Hypogean and epigean amphipods differed in their responses, G. balcanicus being more sensitive to the toxic effects of heavy metals than the hypogean N montellianus. The degree of tolerance was Cubiological indicator for monitoring groundwater heavy metal pollution.

  6. The performance and subjective responses of call-center operators with new and used supply air filters at two outdoor air supply rates

    DEFF Research Database (Denmark)

    Wargocki, Pawel; Wyon, David; Fanger, Povl Ole

    2004-01-01

    . Their performance was continuously monitored by recording the average talk-time every 30 min. Replacing a used filter with a clean filter reduced talk-time by about 10% at the high ventilation rate but had no significant effect at the low rate. Increasing the outdoor air supply rate reduced talk-time by 6......A 2X2 replicated field intervention experiment was conducted in a call-center providing a telephone directory service: outdoor air supply rate was adjusted to be 8% of the total airflow of 430 l/s (3.5/h)and the supply air filters were either new or had been in place for 6 months. One......% with a new filter in place but increased talk-time by 8% with a used filter in place. The interventions also had significant effects on some SBS symptoms and environmental perceptions. The present results indicate that increasing outdoor air supply rate and replacing filters can have positive effects...

  7. The response of the maize nitrate transport system to nitrogen demand and supply across the lifecycle.

    Science.gov (United States)

    Garnett, Trevor; Conn, Vanessa; Plett, Darren; Conn, Simon; Zanghellini, Juergen; Mackenzie, Nenah; Enju, Akiko; Francis, Karen; Holtham, Luke; Roessner, Ute; Boughton, Berin; Bacic, Antony; Shirley, Neil; Rafalski, Antoni; Dhugga, Kanwarpal; Tester, Mark; Kaiser, Brent N

    2013-04-01

    An understanding of nitrate (NO3-) uptake throughout the lifecycle of plants, and how this process responds to nitrogen (N) availability, is an important step towards the development of plants with improved nitrogen use efficiency (NUE). NO3- uptake capacity and transcript levels of putative high- and low-affinity NO3- transporters (NRTs) were profiled across the lifecycle of dwarf maize (Zea mays) plants grown at reduced and adequate NO3-. Plants showed major changes in high-affinity NO3- uptake capacity across the lifecycle, which varied with changing relative growth rates of roots and shoots. Transcript abundances of putative high-affinity NRTs (predominantly ZmNRT2.1 and ZmNRT2.2) were correlated with two distinct peaks in high-affinity root NO3- uptake capacity and also N availability. The reduction in NO3- supply during the lifecycle led to a dramatic increase in NO3- uptake capacity, which preceded changes in transcript levels of NRTs, suggesting a model with short-term post-translational regulation and longer term transcriptional regulation of NO3- uptake capacity. These observations offer new insight into the control of NO3- uptake by both plant developmental processes and N availability, and identify key control points that may be targeted by future plant improvement programmes to enhance N uptake relative to availability and/or demand.

  8. Morphological and physiological responses of Scots pine fine roots to water supply in a dry climatic region in Switzerland.

    Science.gov (United States)

    Brunner, Ivano; Pannatier, Elisabeth Graf; Frey, Beat; Rigling, Andreas; Landolt, Werner; Zimmermann, Stephan; Dobbertin, Matthias

    2009-04-01

    In recent decades, Scots pine (Pinus sylvestris L.) forests in inner-Alpine dry valleys of Switzerland have suffered from drought and elevated temperatures, resulting in a higher mortality rate of trees than the mean mortality rate in Switzerland. We investigated the responses of fine roots (standing crop, morphological and physiological features) to water supply in a Scots pine forest in the Rhone valley. Before irrigation started in 2003, low- and high-productivity Scots pine trees were selected based on their crown transparency. The fine root standing crop measured in spring from 2003 to 2005 was unaffected by the irrigation treatment. However, irrigation significantly enhanced the fine root standing crop during the vegetation period when values from spring were compared with values from fall in 2005. Irrigation slightly increased specific root length but decreased root tissue density. Fine root O2-consumption capacity decreased slightly in response to the irrigation treatment. Using ingrowth cores to observe the responses of newly produced fine roots, irrigation had a significantly positive effect on the length of fine roots, but there were no differences between the low- and high-productivity trees. In contrast to the weak response of fine roots to irrigation, the aboveground parts responded positively to irrigation with more dense crowns. The lack of a marked response of the fine root biomass to irrigation in the low- and high-productivity trees suggests that fine roots have a high priority for within-tree carbon allocation.

  9. Multi-responsive metal-organic lantern cages in solution.

    Science.gov (United States)

    Brega, Valentina; Zeller, Matthias; He, Yufan; Lu, H Peter; Klosterman, Jeremy K

    2015-03-25

    Soluble copper-based M4L4 lantern-type metal-organic cages bearing internal amines were synthesized. The solution state integrity of the paramagnetic metal-organic cages was demonstrated using NMR, DLS, MS, and AFM spectroscopy. 1D supramolecular pillars of pre-formed cages or covalent host-guest complexes selectively formed upon treatment with 4,4'-bipyridine and acetic anhydride, respectively.

  10. Effects of interdigitated platinum finger geometry on spectral response characteristics of germanium metal-semiconductor-metal photodetectors.

    Science.gov (United States)

    Yang, Hyun-Duk; Janardhanam, V; Shim, Kyu-Hwan; Choi, Chel-Jong

    2014-10-01

    We fabricated interdigitated germanium (Ge) metal-semiconductor-metal photodetectors (MSM PDs) with interdigitated platinum (Pt) finger electrodes and investigated the effects of Pt finger width and spacing on their spectral response. An increase in the incident optical power enhances the creation of electron-hole pairs, resulting in a significant increase in photo current. Lowering of the Schottky barrier could be a main cause of the increase in both photo and dark current with increasing applied bias. The manufactured Ge MSM PDs exhibited a considerable spectral response for wavelengths in the range of 1.53-1.56 μm, corresponding to the entire C-band spectrum range. A reduction in the area fraction of the Pt finger electrode in the active region by decreasing and increasing finger width and spacing, respectively, led to an increase in illuminated active area and suppression of dark current, which was responsible for the improvement in responsivity and quantum efficiency of Ge MSM PDs.

  11. The response of low to moderate sediment supply incised valley systems to episodic sea-level rises

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, M.A.; Anderson, J.B.; Siringan, F.P. (Rice Univ., Houston, TX (United States))

    1991-03-01

    Low to moderate sediment supply incised valley systems (e.g., the Trinity, Sabine, and Lavaca rivers) are characterized by mud-dominated estuarine fill and by sedimentation that is limited to the valley cut during low sea level. In contrast, within the high sediment supply Brazos valley system substantial sedimentation has occurred between the lowstand valleys for at least the last 7000 years. Within the Trinity/Sabine incised valley system, sand prone facies include fluvial and tidal inlet deposits. Fluvial deposits are relatively uniform in thickness and distribution, while tidal inlets form discontinuous and pod-like deposits. The valley-fill stratigraphy consists of transgressive parasequences, whose bounding flooding surfaces can be mapped with core and high resolution seismic data. Each parasequences is represented by paired upper bay marsh/bayhead delta and tidal inlet/flood tidal delta facies. Coeval shoreline facies are reworked during the sea-level rise that terminates a particular parasequence. Over 200 sediment cores from the study area are used to define the shapes of these sand bodies, and to establish their origin based on grain sizes, sedimentary structures, and faunal assemblages. The stratigraphy interpreted from these low to moderate sediment supply incised valley systems imply sea level rose episodically during the last transgression. Rapid sea-level rises are responsible for development of isolated shelf sand deposits and may correlate to stream piracy events in the nearby Brazos system. Ongoing investigations concentrate on the distal portions of the incised valleys where they become the feeders to shelf margin deposits within the lowstand systems tract.

  12. Biosynthesis of metal-binding polypeptides and their precursors in response to cadmium in Datura innoxia

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, P.J.; Delhaize, E.; Kuske, C.R.

    1991-01-01

    Metal-tolerant Datura innoxia cells synthesize large amounts of a class of metal-binding polypeptides, poly({gamma}-glutamylcysteinyl) glycines (({gamma}-EC){sub n}G, n=2-5), when exposed to Cd. These polypeptides have a high affinity for Cd (2) and certain other metal ions and are thought to play a role in metal tolerance in higher plants. ({gamma}-EC){sub n}G is biosynthetically derived from glutathione. Therefore, the response of Datura cells to Cd must include an increase in production of glutathione and its precursors, since cells rapidly accumulate very high concentrations of these metal-binding polypeptides. The biosynthesis of ({gamma}-EC){sub n}Gs, glutathione, and cysteine in response to Cd exposure is described. The physiological significance of the synthesis of these polypeptides and their precursors and its relevance to Cd tolerance and metal homeostasis are discussed. 34 refs., 6 figs., 1 tab.

  13. Determining Reliable Networks of Prepositioning Materiel Warehouses for Public-Sector Rapid Response Supplies

    Directory of Open Access Journals (Sweden)

    Thomas E. Lang

    2016-01-01

    Full Text Available Events such as natural disasters or combat operations require a rapid response capability from humanitarian service providers and military organizations. Such organizations can decrease their response times through the prepositioning of materiel in forward warehouses, reducing the time needed to transport items to the site of need. A particular challenge to the development of networks of prepositioning warehouses is that the warehouses themselves may be impacted by the very disruptions that drive demands for prepositioned materials. The objective of this research is to identify a reliable network posture, which is a set of utilized facility locations and an allocation of materiel to those locations, that can satisfy time-sensitive delivery requirements to potential locations around the globe, ensuring that demands can be satisfied even in the event of loss of access to a subset of storage sites (along with said sites’ materiel, all at minimum total cost. We develop new optimization formulations to account for differing levels of network reliability, all reflecting the time-sensitive environment faced by rapid response operations. We demonstrate an application of this methodology using rapid response material prepositioned by the US Air Force.

  14. Transcriptomic profiling of Arabidopsis gene expression in response to varying micronutrient zinc supply

    DEFF Research Database (Denmark)

    Azevedo, Herlânder; Azinheiro, Sarah Gaspar; Muñoz-Mérida, Antonio

    2016-01-01

    Deficiency of the micronutrient zinc is a widespread condition in agricultural soils, causing a negative impact on crop quality and yield. Nevertheless, there is an insufficient knowledge on the regulatory and molecular mechanisms underlying the plant response to inadequate zinc nutrition [1...

  15. Lecture-Tutorial Coherency: Student-Supplied Written Responses As Indicators of Academic Success

    Science.gov (United States)

    Eckenrode, J.; Welch, J. D.; Saldivar, H.; Prather, E. E.; Wallace, C. S.; CATS

    2013-04-01

    The Lecture-Tutorial Coherency Project investigates the correlation between correctness and coherency in students' written Lecture-Tutorial (LT) responses, and their understanding of introductory astronomy content. Astronomy education researchers, including undergraduate students from the CAE Ambassadors Program (former Astro 101 students who serve as instructional assistants), created rubrics designed to assess the correctness and coherency of students' written explanations of reasoning for three LT questions from the 2010 semester and four LT questions from the 2011 semester. We used these rubrics to score the LT responses of over 1300 students. We compared the average of students' written correctness and coherency scores to their responses to LSCI questions and conceptually difficult and closely related multiple-choice exam items. Our data indicates no significant difference in the correctness of student responses between students who write weak vs. robust scientific explanations of reasoning. However, it is worth noting that the average LSCI normalized gain scores and average exam-question scores for this population of students (regardless of their correctness and coherency cores) is higher than what is typically achieved by students after traditional lecture-based instruction or from low-interactivity classrooms. These results suggest that the cognitive engagement required to complete the Socratic-dialog driven LT activities is sufficient to promote higher levels of conceptual understanding regardless of whether the students actually write out their explanations.

  16. Metal stress in zooplankton diapause production: post-hatching response.

    Science.gov (United States)

    Aránguiz-Acuña, Adriana; Pérez-Portilla, Pablo

    2017-04-01

    Aquatic organisms commonly respond to harsh conditions by forming diapausing stages, which enable populations to survive adverse periods forming egg banks. Production of diapausing eggs is frequently observed in monogonont rotifers, previously changing from asexual to partial sexual reproduction (mixis). In despite that zooplankton are frequently used in ecotoxicological assessment because of their sensitivity to various toxicants and their important role in the ecosystems, toxicity evaluations often consider the directly exposed population produced by parthenogenetic reproduction, exclusively. We assessed experimentally effects of exposure to metals on mixis delay and fitness of hatchlings of the rotifer Brachionus plicatilis obtained from a brackish water lagoon with high metal content, especially copper. We show that sub-lethal concentrations of copper affected traits related to sexual reproduction and diapausing egg production in the rotifer. Copper addition did not delay the start of mixis, suggesting that rapid initiation of mixis is promoted in risky environments, according to the hypothesis of mixis as an escape strategy. Higher investment in mixis was obtained when individuals were exposed to metal. Addition of copper negatively affected the hatching success of diapausing eggs and performance of hatchlings. Nevertheless, these effects were greater for individuals formed in non-metal conditions, suggesting an adaptive advantage of populations from natural sediments exposed to copper. These results highlight the ecological and evolutionary consequences of the presence of metals in freshwater environments by modulating diapause adaptive efficacy and the selective process in egg banks.

  17. Logistics orchestration in the ornamental plant supply chain network: towards responsive and differentiated demand driven networks

    OpenAIRE

    Vorst, van der, H.A.; Duineveld, M.P.J.; Scheer, F.P.

    2007-01-01

    At the moment the Dutch ornamental plant sector has a dominant international position fulfilling about 44% of the European market. However, emerging markets are positioned at a great distance requiring new logistics concepts to operate efficiently and effectively, new marketing channels become apparent which require increased responsiveness and product diversification, and new competitors like Spain and Italy are entering the arena. If no action is taken, the Dutch might loose their renowned ...

  18. INFLUENCE OF SUPPLY AND DEMAND FACTORS AT THE DEVELOPMENT OF ENVIRONMENTALLY RESPONSIBLE HOUSING AND UTILITIES SECTOR IN THE RUSSIAN FEDERATION

    Directory of Open Access Journals (Sweden)

    Natalia B. Safronova

    2016-11-01

    Full Text Available Empirical marketing regional research on supply and demand factors of housing and communal services (HCS revealed determinants of customer loyalty and satisfaction with the service level and factors influencing on willingness to purchase additional services. Specific features of housing and utilities sector (HUS as a social significant industry determine requirements to models reflecting reciprocal influence of indices of satisfaction, loyalty and economic indices of operation. The article presents definition of requirements along with development of techniques for modeling influence of satisfaction and loyalty on consumer behaviour of clients. The authors demonstrate trustworthy statistical results of correlative interrelationship of different factors. There have been designed regression models for taking management solutions by executives of management company housing and communal services at the development environmental responsibility. The causes that lead and hamper development of socially oriented services in different regions of the Russian Federation have been identified.

  19. Brassinosteroids and Response of Plants to Heavy Metals Action

    Science.gov (United States)

    Rajewska, Iwona; Talarek, Marta; Bajguz, Andrzej

    2016-01-01

    Brassinosteroids (BRs) are a widespread group of plant hormones. These phytohormones play a crucial role in the regulation of growth and development of various plant species, and they demonstrate high biological activity. BRs are considered to demonstrate protective activity in the plants exposed to various stresses. Due to rapid industrialization and urbanization, heavy metals have become one of the most important plant stressors. In plants, accumulation of heavy metals beyond the critical levels leads to oxidative stress. However, BRs may inhibit the degradation of lipids, resulted from the overproduction of reactive oxygen species under stress conditions, and increase the activity of antioxidants. They also have the ability to promote phytochelatins synthesis. PMID:27242833

  20. Toxicological Response of the Green Alga Chlorella vulgaris, to Some Heavy Metals

    Directory of Open Access Journals (Sweden)

    E. Afkar

    2010-01-01

    Full Text Available Problems statement: The disturbance of aquatic ecosystems provoked by heavy metals pollution from industrial and domestic sources, has as consequence the loss of biological diversity, as well as increased bioaccumulation and magnification of toxicants in the food chain. The aim of this study was to evaluate the effect of some heavy metals on some physiological activities of Chlorella vulgaris beyerinck with special references to metal bioaccumulation. Approach: Chlorella vulgaris Beyerinck was isolated from Al-Asfar Lake, Al-Hassa, Saudi Arabia. A standard initial inoculum of the isolated algae was inoculated to culture flasks. The culture flasks were supplied with various concentrations of Cobalt, Copper and Zinc ranging from 10-6-10-9 M. At the end of the incubation period cultures were filtered and washed several times by distilled water for measurements the various experimental parameters. Results: The data show that the lower doses of the three tested metals had stimulatory effect in biomass yield of Chlorella vulgaris, whereas the higher doses were inhibitory depending on the type of the metal. The inhibitory effect of copper to the growth parameters of Chlorella vulgaris was more pronounced than other two tested metals. The total protein content, total carbohydrate and the total free amino acids of the tested green alga Chlorella vulgaris gradually decreased in a manner dependent on the metal concentration in the medium. On the other hand, bioaccumulation of cobalt, copper and zinc by Chlorella vulgaris cells were parallel to increasing the concentrations in the culture medium. Conclusion: The inhibitory and stimulatory effects of either of the used heavy metals depend on concentration. Different organisms, however, have different sensitivities to the same metal and the same organisms may be more or less damaged by different metals. The uptake of an element from the surrounding medium is seldom exactly proportional to the amount present

  1. An Agri-Food Supply Chain Model to Enhance the Business Skills of Small-Scale Farmers Using Corporate Social Responsibility

    OpenAIRE

    Wahyudi Sutopo; Muh. Hisjam; Yuniaristanto Yuniaristanto

    2012-01-01

    In general, small-scale vegetable farmers experience problems in improving the safety and quality of vegetables for supplying high-class consumers in modern retailers. Farmer Group and/or Cooperative (FGC) should be able to assist its members to meet the relevant provisions of modern retail on product specifications, delivery terms, and internal business requirements. This study proposed an agri-food supply chain (ASC) model that involves the corporate social responsibility (CSR) activities t...

  2. Salt marsh equilibrium states and transient dynamics in response to changing rates of sea level rise and sediment supply

    Science.gov (United States)

    D'Alpaos, A.; Mudd, S. M.; Carniello, L.

    2012-12-01

    Understanding and predicting the response of salt-marsh bio-geomorphic systems to changes in the rate of sea level rise and sediment supply is an issue of paramount importance due to the crucial role exerted by salt marshes within the tidal landscape. Salt-marsh platforms, in fact, buffer coastlines against storms, filter nutrients and pollutants from tidal waters, provide nursery areas for coastal biota, and serve as a sink for organic carbon. Observations of marsh degradation worldwide and the acceleration in the rate of global sea level rise highlight the importance of improving our understanding of the chief processes which control salt-marsh response to current natural climate changes and to the effects of variations in sediment supply. The results of our analytical model of salt-marsh bio-morphodynamic evolution in the vertical plane, accounting for two-way interactions between ecological and geomorphological processes, show that marshes are more resilient to a step decrease in the rate of relative sea level rise rather than to a step increase of the same magnitude. Interestingly, marshes respond more rapidly to an increase in sediment load or vegetation productivity, rather than to a decrease (of the same amount) in sediment load or vegetation productivity. Model results also suggest that marsh stability is positively correlated with tidal range: marshes with high tidal ranges respond more slowly to changes in the environmental forcings and therefore are less likely to be affected by perturbations than their counterparts in low tidal ranges. Finally, the model suggests that, in the case of a oscillating rate of sea level rise, marsh stratigraphy will be unable to fully record short term fluctuations in relative mean sea level, whereas it will be able to capture long term fluctuations particularly in sediment rich, microtidal settings.

  3. Motor responses of muscles supplied by cranial nerves to subthalamic nucleus deep brain stimuli.

    Science.gov (United States)

    Costa, João; Valls-Solé, Josep; Valldeoriola, Francesc; Rumià, Jordi; Tolosa, Eduardo

    2007-01-01

    The distribution of human corticobulbar motor excitatory and inhibitory output is not fully understood. In particular, it is unclear whether the pattern of innervation is the same for upper and lower facial muscles, and what is the motor cortical area giving rise to such innervation. We used electrodes implanted in the subthalamic nucleus (STN) in patients with Parkinson's disease to activate motor tracts at a subcortical level. We examined the excitatory and inhibitory effects of unilateral single STN deep brain stimulation (sSTN-DBS) in 14 patients by taking recordings from facial, cervical and upper limb muscles on both sides. We measured the latency and amplitude of the motor-evoked potentials (MEPs), and the latency and duration of the silent periods, and compared ipsilateral with contralateral responses and responses obtained in different muscles. Unilateral sSTN-DBS induced strictly contralateral MEPs in the trapezius, deltoid, biceps and thenar muscles. The same stimulus always induced bilateral MEPs in the orbicularis oculi, orbicularis oris, masseter and sternocleidomastoid at a mean latency in the range 6.0-9.1 ms. MEP latencies in the orbicularis oculi and orbicularis oris were significantly longer than in the masseter and sternocleidomastoid (P motor nuclei descend together at the level of the STN. These findings are relevant in the discussion of the innervation of upper and lower facial muscles in humans and in the interpretation of previous results obtained with transcranial cortical stimulation.

  4. Hepatic arteriolo-portal venular shunting guarantees maintenance of nutritional microvascular supply in hepatic arterial buffer response of rat livers.

    Science.gov (United States)

    Richter, S; Vollmar, B; Mücke, I; Post, S; Menger, M D

    2001-02-15

    To elucidate the hepatic microvascular response upon the hepatic arterial buffer response (HABR), we analysed blood flow (ultrasonic flowprobes) of the hepatic artery (HA) and portal vein (PV), microcirculation (intravital microscopy), and tissue oxygenation (polarography) in anaesthetized Sprague-Dawley rats and re-evaluated the role of adenosine in mediating the HABR by using 8-phenyltheophylline as a competitive antagonist. 2. Upon restriction of PV blood flow to 11 +/- 3 % of baseline values, HA blood flow increased by a factor of 1.77 (P portal venules (TPVs) decreased to only 66 % (P portal venular shunting. As a consequence, red blood cell velocity and volumetric blood flow in sinusoids were found to be reduced to only 66-68 % compared with baseline (P oxygen delivery, despite the marked reduction of total liver blood flow. Further, hepatic arteriolo-portal venular shunting guaranteed homogeneity of nutritive blood flow upon HABR, as given by an unchanged intra-acinar coefficient of variance of sinusoidal perfusion. 4. Pretreatment of animals with the adenosine antagonist 8-phenyltheophylline completely blocked the hepatic arterial buffer response with the consequence of decreased tissue oxygenation and increased heterogeneity of sinusoidal perfusion. 5. In conclusion, hepatic microhaemodynamics, in particular unchanged diameters of THAs, TPVs and sinusoids, during HABR indicate that reduction in resistance to HA flow is located upstream and functions via hepatic arteriolo-portal venular shunts resulting in equal distribution of microvascular blood flow and oxygen delivery under conditions of restricted PV blood supply.

  5. Cellular Responses to the Metal-Binding Properties of Metformin

    Science.gov (United States)

    Logie, Lisa; Harthill, Jean; Patel, Kashyap; Bacon, Sandra; Hamilton, D. Lee; Macrae, Katherine; McDougall, Gordon; Wang, Huan-Huan; Xue, Lin; Jiang, Hua; Sakamoto, Kei; Prescott, Alan R.; Rena, Graham

    2012-01-01

    In recent decades, the antihyperglycemic biguanide metformin has been used extensively in the treatment of type 2 diabetes, despite continuing uncertainty over its direct target. In this article, using two independent approaches, we demonstrate that cellular actions of metformin are disrupted by interference with its metal-binding properties, which have been known for over a century but little studied by biologists. We demonstrate that copper sequestration opposes known actions of metformin not only on AMP-activated protein kinase (AMPK)-dependent signaling, but also on S6 protein phosphorylation. Biguanide/metal interactions are stabilized by extensive π-electron delocalization and by investigating analogs of metformin; we provide evidence that this intrinsic property enables biguanides to regulate AMPK, glucose production, gluconeogenic gene expression, mitochondrial respiration, and mitochondrial copper binding. In contrast, regulation of S6 phosphorylation is prevented only by direct modification of the metal-liganding groups of the biguanide structure, supporting recent data that AMPK and S6 phosphorylation are regulated independently by biguanides. Additional studies with pioglitazone suggest that mitochondrial copper is targeted by both of these clinically important drugs. Together, these results suggest that cellular effects of biguanides depend on their metal-binding properties. This link may illuminate a better understanding of the molecular mechanisms enabling antihyperglycemic drug action. PMID:22492524

  6. Optical Magnetic Response in a Single Metal Nanobrick

    CERN Document Server

    Tang, Jianwei

    2011-01-01

    Anti-symmetric localized surface plasmons are demonstrated on a single silver nanostrip sandwiched by SiC layers. By employing the resonance of anti-symmetric localized surface plasmons, we enable single metal nanobricks to produce optical magnetism, in the blue and violet light range, as well as in a part of the ultraviolet light range. The physical mechanism is explained.

  7. Plant response to air pollution by heavy metals

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawa, Y.; Mitsuki, H.; Takata, N.

    1975-01-01

    The effect of air pollutants on the concentration of heavy metals in leaves of trees in the neighborhood of a steel factory was studied. Paulownia trees, which absorb and accumulate heavy metals better than other trees, were sampled in the middle of November. The concentration of heavy metals in the soil was measured for every 10 cm vertically downward to a depth of 80 cm near the roots of the sample trees. The concentrations of iron and manganese in the dust were 34.6 to 57.8% and 0.41 to 3.21%, respectively, mainly in oxidized form. The amounts of these metals discharged from the factories were calculated from the concentrations in the atmosphere. Tree leaves in the polluted area were analyzed to determine the route of atmospheric iron from the source to the atmosphere to the soil, where it is absorbed by the roots to accumulate in the leaves. The concentration of Mn in soil exponentially decreases with distance from the source, but its concentration in tree leaves increases with distance. 4 figures.

  8. Toxicological Responses of Environmental Mixtures: Environmental Metals Mixtures Display Synergistic Induction of Metal-Responsive and Oxidative Stress Genes in Placental Cells

    Science.gov (United States)

    Adebambo, Oluwadamilare A.; Ray, Paul D.; Shea, Damian; Fry, Rebecca C.

    2016-01-01

    Exposure to elevated levels of the toxic metals inorganic arsenic (iAs) and cadmium (Cd) represents a major global health problem. These metals often occur as mixtures in the environment, creating the potential for interactive or synergistic biological effects different from those observed in single exposure conditions. In the present study, environmental mixtures collected from two waste sites in China and comparable mixtures prepared in the laboratory were tested for toxicogenomic response in placental JEG-3 cells. These cells serve as a model for evaluating cellular responses to exposures during pregnancy. One of the mixtures was predominated by iAs and one by Cd. Six gene biomarkers were measured in order to evaluate the effects from the metals mixtures using dose and time-course experiments including: heme oxygenase 1 (HO-1) and metallothionein isoforms (MT1A, MT1F and MT1G) previously shown to be preferentially induced by exposure to either iAs or Cd, and metal transporter genes aquaporin-9 (AQP9) and ATPase, Cu2+ transporting, beta polypeptide (ATP7B). There was a significant increase in the mRNA expression levels of ATP7B, HO-1, MT1A, MT1F, and MT1G in mixture-treated cells compared to the iAs or Cd only-treated cells. Notably, the genomic responses were observed at concentrations significantly lower than levels found at the environmental collection sites. These data demonstrate that metal mixtures increase the expression of gene biomarkers in placental JEG-3 cells in a synergistic manner. Taken together, the data suggest that toxic metals that co-occur may induce detrimental health effects that are currently underestimated when analyzed as single metals. PMID:26472158

  9. Toxicological responses of environmental mixtures: Environmental metal mixtures display synergistic induction of metal-responsive and oxidative stress genes in placental cells.

    Science.gov (United States)

    Adebambo, Oluwadamilare A; Ray, Paul D; Shea, Damian; Fry, Rebecca C

    2015-12-15

    Exposure to elevated levels of the toxic metals inorganic arsenic (iAs) and cadmium (Cd) represents a major global health problem. These metals often occur as mixtures in the environment, creating the potential for interactive or synergistic biological effects different from those observed in single exposure conditions. In the present study, environmental mixtures collected from two waste sites in China and comparable mixtures prepared in the laboratory were tested for toxicogenomic response in placental JEG-3 cells. These cells serve as a model for evaluating cellular responses to exposures during pregnancy. One of the mixtures was predominated by iAs and one by Cd. Six gene biomarkers were measured in order to evaluate the effects from the metal mixtures using dose and time-course experiments including: heme oxygenase 1 (HO-1) and metallothionein isoforms (MT1A, MT1F and MT1G) previously shown to be preferentially induced by exposure to either iAs or Cd, and metal transporter genes aquaporin-9 (AQP9) and ATPase, Cu(2+) transporting, beta polypeptide (ATP7B). There was a significant increase in the mRNA expression levels of ATP7B, HO-1, MT1A, MT1F, and MT1G in mixture-treated cells compared to the iAs or Cd only-treated cells. Notably, the genomic responses were observed at concentrations significantly lower than levels found at the environmental collection sites. These data demonstrate that metal mixtures increase the expression of gene biomarkers in placental JEG-3 cells in a synergistic manner. Taken together, the data suggest that toxic metals that co-occur may induce detrimental health effects that are currently underestimated when analyzed as single metals.

  10. Dynamic Response of Metal-Polymer Bilayers - Viscoelasticity, Adhesion and Failure

    Science.gov (United States)

    2013-11-25

    stretch of two at a strain rate of 103 s_1 a pulse duration of 2 ms is required! Recently, Youssef and Gupta [8] have developed a laser ablation based...Dynamic Response of Metal -Polymer Bilayers and Failure Viscoelasticity, Adhesion Sa. CONTRACT NUMBER 5b. GRANT NUMBER N00014-09-1-0541 5c...Contract Number N00014-09-1-0541 Title of Research Dynamic Response of Metal -Polymer Bilayers - Viscoelasticity, Adhesion and Failure Principal

  11. Morphological responses of barley roots to soil compaction and modified supply of oxygen

    Directory of Open Access Journals (Sweden)

    A. SIMOJOKI

    2008-12-01

    Full Text Available The morphological changes in barley roots in response to soil compaction and hypoxia were quantified by image analysis. Based on the assumption that these soil stresses increase endogenous ethylene production in plants, changes indicating higher construction costs for roots, such as decreased specific root length, were expected. The hypothesis was found to be only partly correct. Most morphological changes of barley roots were probably a reaction to increased soil mechanical impedance. Examples of this are root width, which was increased by compaction apart from in wet soil, as well as increased width and specific volume, and a decreased specific length of roots in the deepest layer of well-aerated loose soil. However, in loose moist soil hypoxia prevented root growth, but did not change root morphology. The results suggest that severe hypoxia lessens the possibilities of roots to adapt to the hypoxic soil by reducing root growth and by preventing the formation of aerenchyma. ;

  12. Enhanced nonlinear optical response of one-dimensional metal-dielectric photonic crystals.

    Science.gov (United States)

    Lepeshkin, Nick N; Schweinsberg, Aaron; Piredda, Giovanni; Bennink, Ryan S; Boyd, Robert W

    2004-09-17

    We describe a new type of artificial nonlinear optical material composed of a one-dimensional metal-dielectric photonic crystal. Because of the resonant nature of multiple Bragg reflections, the transmission within the transmission band can be quite large, even though the transmission through the same total thickness of bulk metal would be very small. This procedure allows light to penetrate into the highly nonlinear metallic layers, leading to a large nonlinear optical response. We present experimental results for a Cu/SiO(2) crystal which displays a strongly enhanced nonlinear optical response (up to 12X) in transmission.

  13. Growth and nutrient efficiency of Betula alnoides clones in response to phosphorus supply

    Directory of Open Access Journals (Sweden)

    Lin Chen

    2016-12-01

    Full Text Available As phosphorus deficiency limits the productivity of many plantation forests in Asia, there is considerable interest in developing phosphorus-efficient clones for the region through targeted breeding programs. Therefore, we determined growth, nutrient concentrations and nutrient absorption and utility efficiencies of four Betula alnoides clones (C5, C6, 1-202 and BY1 in response to six phosphorus levels of 0, 17, 52, 70, 140 and 209 mg P plant-1 coded as P1 to P6, respectively. Maximum growth occurred in the P4, P5 and P6 plants since they had the largest height, biomass, leaf area and branch number. Phosphorus application increased the phosphorus concentrations of all clones. Nutrient loading was achieved with the P6 treatment because growth and biomass were not significantly higher, but root, stem and leaf phosphorus concentrations were approximately twice those of P4 plants. Clone BY1 had the highest phosphorus-efficiency, and is recommended for field application due to its maximum root collar diameter, biomass, root/shoot ratio, leaf area, nutrient absorption and utility efficiency among the four clones. The findings will help to improve the nutrient efficiency of this species in plantation forestry in Asia.

  14. Growth and nutrient efficiency of Betula alnoides clones in response to phosphorus supply

    Directory of Open Access Journals (Sweden)

    Lin Chen

    2016-12-01

    Full Text Available As phosphorus deficiency limits the productivity of many plantation forests in Asia, there is considerable interest in developing phosphorus-efficient clones for the region through targeted breeding programs. Therefore, we determined growth, nutrient concentrations and nutrient absorption and utility efficiencies of four Betula alnoides clones (C5, C6, 1-202 and BY1 in response to six phosphorus levels of 0, 17, 52, 70, 140 and 209 mg P plant-1 coded as P1 to P6, respectively. Maximum growth occurred in the P4, P5 and P6 plants since they had the largest height, biomass, leaf area and branch number. Phosphorus application increased the phosphorus concentrations of all clones. Nutrient loading was achieved with the P6 treatment because growth and biomass were not significantly higher, but root, stem and leaf phosphorus concentrations were approximately twice those of P4 plants. Clone BY1 had the highest phosphorus-efficiency, and is recommended for field application due to its maximum root collar diameter, biomass, root/shoot ratio, leaf area, nutrient absorption and utility efficiency among the four clones. The findings will help to improve the nutrient efficiency of this species in plantation forestry in Asia.

  15. A novel response of wild-type duckweed (Lemna paucicostata Hegelm.) to heavy metals.

    Science.gov (United States)

    Li, Tianyu; Xiong, Zhiting

    2004-04-01

    The responses of wild-type Lemna paucicostata, used as the experimental stock, to seven heavy metals were investigated with a hydroponic culture in a culture facility. The results showed that six of the metals could induce L. paucicostata to release daughter fronds from the mother frond before maturity, resulting in breakup of the colony. This phenomenon is novel and has not been reported before. Six of the heavy metals investigated-copper, cadmium, nickel, zinc, mercury, and chromium-could induce this response, but sensitivity and response of the plant varied. When Cu(2+) at a concentration of 0.2 micromol/L was added, the response was significantly different from that of the control after a 2-h exposure. The response to cadmium (0.8 micromol/L) was significantly different after a 6-h exposure; to zinc (10 micromol/L) and nickel (5 micromol/L), after 5 and 7 h, respectively. But for lead, even at a concentration of 80 micromol/L for 96 h, no colony breakup was induced. The response to heavy metals occurred within 24 h; increasing the exposure by another 24 h had nearly no additional effect on the colony breakup. When the response was over, the number of colonies with fronds varied with the inducement capacity of the metal. Nutrients could affect the sensitivity of L. paucicostata to some heavy metals, such as mercury, chromium, zinc, and nickel, but not to copper and cadmium. Sensitivity was also changed when CuCl(2) was used as the copper source instead of CuSO(4). These results indicate that some heavy metals could serve as a toxicant for inducing L. paucicostata to release daughter fronds in advance. This change might involve a stress response such as ethylene production. Also discussed is the possibility of this response as a biomarker in a bioassay.

  16. Brassinosteroids and response of plants to heavy metals action

    Directory of Open Access Journals (Sweden)

    Iwona eRajewska

    2016-05-01

    Full Text Available Brassinosteroids (BRs are a widespread group of plant hormones. These phytohormones play a crucial role in the regulation of growth and development of various plant species, and they demonstrate high biological activity. BRs are considered to demonstrate protective activity in the plants exposed to various stresses. Due to rapid industrialization and urbanization, heavy metals have become one of the most important plant stressors. In plants, accumulation of heavy metals beyond the critical levels leads to oxidative stress. However, BRs may inhibit the degradation of lipids, resulted from the overproduction of reactive oxygen species under stress conditions, and increase the activity of antioxidants. They also have the ability to promote phytochelatins synthesis.

  17. Interrelated responses of tomato plants and the leaf miner Tuta absoluta to nitrogen supply.

    Science.gov (United States)

    Larbat, R; Adamowicz, S; Robin, C; Han, P; Desneux, N; Le Bot, J

    2016-05-01

    Plant-insect interactions are strongly modified by environmental factors. This study evaluates the influence of nitrogen fertilisation on the tomato (Solanum lycopersicum L.) cv. Santa clara and the leafminer (Tuta absoluta (Meyrick), Lepidoptera: Gelechiidae). Greenhouse-grown tomato plants were fed hydroponically on a complete nutrient solution containing either a high nitrogen concentration (HN) sustaining maximum growth or a low nitrogen concentration (LN) limiting plant growth. Insect-free plants were compared with plants attacked by T. absoluta. Seven and 14 days after artificial oviposition leading to efficacious hatching and larvae development, we measured total carbon, nitrogen and soluble protein as well as defence compounds (phenolics, glycoalkaloids, polyphenol oxidase activity) in the HN versus LN plants. Only in the HN treatment did T. absoluta infestation slightly impair leaf growth and induce polyphenol oxidase (PPO) activity in the foliage. Neither the concentration of phenolic compounds and proteins nor the distribution of nitrogen within the plant was affected by T. absoluta infestation. In contrast, LN nutrition impaired T. absoluta-induced PPO activity. It decreased protein and total nitrogen concentration of plant organs and enhanced the accumulation of constitutive phenolics and tomatine. Moreover, LN nutrition impaired T. absoluta development by notably decreasing pupal weight and lengthening the development period from egg to adult. Adjusting the level of nitrogen nutrition may thus be a means of altering the life cycle of T. absoluta. This study provides a comprehensive dataset concerning interrelated responses of tomato plants and T. absoluta to nitrogen nutrition.

  18. Magnetic Response of Metal-Dielectric Composite at Short Wavelength

    CERN Document Server

    Tang, Jianwei

    2010-01-01

    We propose a new type of split-ring resonator, of which the ring is made of high index dielectric material (e.g. SiC), while metal fills the gap. Such a new magnetic metamaterial is able to operate at short wavelength including the green, blue, violet range and part of ultraviolet range. For ease of fabrication, we also proposed a new type of cut-wire pair structure based on our new type of split-ring resonator.

  19. Optical response of a single noble metal nanoparticle

    Science.gov (United States)

    Muskens, Otto; Christofilos, Dimitris; DelFatti, Natalia; Vallée, Fabrice

    2006-04-01

    The characterization of a single metal nanoobject by comparing its theoretical and experimental far-field spectra measured by a spatial modulation spectroscopy (SMS) technique is discussed in the case of gold and silver nanoparticles. Quantitative determination of the polarization dependent absorption cross-section spectrum of a single nanoparticle is shown to permit its optical identification, i.e., determination of its shape, size and orientation on a surface.

  20. Evaluation of Heavy Metals in Iranian and Non-Iranian Rice Supplied by Shopping Centers of Kashan, Iran

    Directory of Open Access Journals (Sweden)

    Rabbani D.1 PhD,

    2015-01-01

    Full Text Available Aims Heavy metals in the environment are toxic to plants, animals and human. This study aimed to investigate concentration of Arsenic, Lead and Cadmium in Iranian and non- Iranian rice which have been sold in Kashan City, Iran shops. Materials & Methods In this cross-sectional study, 126 samples from 42 trademarks (15 Iranian and 27 non-Iranian rice were collected from Kashan shopping centers. At first each sample was ashed, and then they have been dissolved with nitric acid. Heavy metal concentration was evaluated by inductively coupled plasma emission spectrophotometer. Data were analyzed by SPSS 16 software using One-sample and Independent T-tests. Findings Arsenic was not found in any of rice samples. There was a significant difference between Pb concentration in both Iranian and non-Iranian rice samples. There was not a significance difference between Cd concentration in Iranian (p=0.823 and non-Iranian (p=0.346 rice samples according to Iran national standards but there was a significant difference between Cd concentration in both Iranian (p=0.001 and non-Iranian (p=0.001 rice samples according to WHO and FAO standards. Conclusion Consumed rice pollution with Pb is considerable but with Cd is low. Arsenic concentration in Iranian and non-Iranian rice is less than Iran national and WHO/FAO standards.

  1. Growth but not photosynthesis response of a host plant to infection by a holoparasitic plant depends on nitrogen supply.

    Directory of Open Access Journals (Sweden)

    Hao Shen

    Full Text Available Parasitic plants can adversely influence the growth of their hosts by removing resources and by affecting photosynthesis. Such negative effects depend on resource availability. However, at varied resource levels, to what extent the negative effects on growth are attributed to the effects on photosynthesis has not been well elucidated. Here, we examined the influence of nitrogen supply on the growth and photosynthesis responses of the host plant Mikania micrantha to infection by the holoparasite Cuscuta campestris by focusing on the interaction of nitrogen and infection. Mikania micrantha plants fertilized at 0.2, 1 and 5 mM nitrate were grown with and without C. campestris infection. We observed that the infection significantly reduced M. micrantha growth at each nitrate fertilization and more severely at low than at high nitrate. Such alleviation at high nitrate was largely attributed to a stronger influence of infection on root biomass at low than at high nitrate fertilization. However, although C. campestris altered allometry and inhibited host photosynthesis, the magnitude of the effects was independent of nitrate fertilizations. The infection reduced light saturation point, net photosynthesis at saturating irradiances, apparent quantum yield, CO2 saturated rate of photosynthesis, carboxylation efficiency, the maximum carboxylation rate of Rubisco, and maximum light-saturated rate of electron transport, and increased light compensation point in host leaves similarly across nitrate levels, corresponding to a similar magnitude of negative effects of the parasite on host leaf soluble protein and Rubisco concentrations, photosynthetic nitrogen use efficiency and stomatal conductance across nitrate concentrations. Thus, the more severe inhibition in host growth at low than at high nitrate supplies cannot be attributed to a greater parasite-induced reduction in host photosynthesis, but the result of a higher proportion of host resources

  2. Growth but not photosynthesis response of a host plant to infection by a holoparasitic plant depends on nitrogen supply.

    Science.gov (United States)

    Shen, Hao; Xu, Shu-Jun; Hong, Lan; Wang, Zhang-Ming; Ye, Wan-Hui

    2013-01-01

    Parasitic plants can adversely influence the growth of their hosts by removing resources and by affecting photosynthesis. Such negative effects depend on resource availability. However, at varied resource levels, to what extent the negative effects on growth are attributed to the effects on photosynthesis has not been well elucidated. Here, we examined the influence of nitrogen supply on the growth and photosynthesis responses of the host plant Mikania micrantha to infection by the holoparasite Cuscuta campestris by focusing on the interaction of nitrogen and infection. Mikania micrantha plants fertilized at 0.2, 1 and 5 mM nitrate were grown with and without C. campestris infection. We observed that the infection significantly reduced M. micrantha growth at each nitrate fertilization and more severely at low than at high nitrate. Such alleviation at high nitrate was largely attributed to a stronger influence of infection on root biomass at low than at high nitrate fertilization. However, although C. campestris altered allometry and inhibited host photosynthesis, the magnitude of the effects was independent of nitrate fertilizations. The infection reduced light saturation point, net photosynthesis at saturating irradiances, apparent quantum yield, CO2 saturated rate of photosynthesis, carboxylation efficiency, the maximum carboxylation rate of Rubisco, and maximum light-saturated rate of electron transport, and increased light compensation point in host leaves similarly across nitrate levels, corresponding to a similar magnitude of negative effects of the parasite on host leaf soluble protein and Rubisco concentrations, photosynthetic nitrogen use efficiency and stomatal conductance across nitrate concentrations. Thus, the more severe inhibition in host growth at low than at high nitrate supplies cannot be attributed to a greater parasite-induced reduction in host photosynthesis, but the result of a higher proportion of host resources transferred to the parasite at

  3. 基于Supply-Hub的生鲜农产品快速反应配送驱动机制研究%Study on Quick Response Driving Mechanism of Fresh Agricultural Products Distribution Based on Supply-Hub

    Institute of Scientific and Technical Information of China (English)

    张阐军; 李文

    2013-01-01

    针对生鲜农产品物流配送低效率、高损耗等现象,文中构建基于Supply-Hub的生鲜农产品供应链物流快速反应系统框架。通过建立系统二级驱动指标随机需求驱动动态模型,结合层次分析法(AHP)和计算机仿真分析农产品供应链物流一级决策指标运作机制、动态性能和反应规律。研究结果表明,物流中心协同性直接影响系统整体响应能力,且合理的提前期一致性对安全库存水平、配送质量和服务能力具有直接相关性。%For the problems of low efficiency,high loss etc.in fresh agricultural products logistics distribution,this paper build a quick response system framework of fresh agricultural products supply chain logistics based on Supply-Hub.Through the establishment of random dynamic model driving by demand index system of two steps,and analyzed the decision -making mechanisms,dynamic performance and operation rules of the first step logistics indexes on agricultural products supply chain combing the analytic hierarchy process (AHP)and computer simulation.The results show that,the Supply-Hub’s coordination stage affects directly the system overall response capability,and a reasonable lead time consistency has direct correlation on safety stock level,distribution quality and serviceability.

  4. Strategic Supply

    Science.gov (United States)

    2003-01-01

    March 7, 2003. [29] Velis, Lil. “ Publishing Industry : Supply Chain Strategy in Action,” briefing presented to ICAF Strategic Supply Seminar, May 6...Lambert and Stock, page 48. [32] Velis, Lil. “ Publishing Industry : Supply Chain Strategy in Action,” briefing presented to ICAF Strategic Supply

  5. Metal dealing at the origin of the Chordata phylum: the metallothionein system and metal overload response in amphioxus.

    Directory of Open Access Journals (Sweden)

    Maria Guirola

    Full Text Available Non-vertebrate chordates, specifically amphioxus, are considered of the utmost interest for gaining insight into the evolutionary trends, i.e. differentiation and specialization, of gene/protein systems. In this work, MTs (metallothioneins, the most important metal binding proteins, are characterized for the first time in the cephalochordate subphylum at both gene and protein level, together with the main features defining the amphioxus response to cadmium and copper overload. Two MT genes (BfMT1 and BfMT2 have been identified in a contiguous region of the genome, as well as several ARE (antioxidant response element and MRE (metal response element located upstream the transcribed region. Their corresponding cDNAs exhibit identical sequence in the two lancelet species (B. floridae and B. lanceolatum, BfMT2 cDNA resulting from an alternative splicing event. BfMT1 is a polyvalent metal binding peptide that coordinates any of the studied metal ions (Zn, Cd or Cu rendering complexes stable enough to last in physiological environments, which is fully concordant with the constitutive expression of its gene, and therefore, with a metal homeostasis housekeeping role. On the contrary, BfMT2 exhibits a clear ability to coordinate Cd(II ions, while it is absolutely unable to fold into stable Cu (I complexes, even as mixed species. This identifies it as an essential detoxification agent, which is consequently only induced in emergency situations. The cephalochordate MTs are not directly related to vertebrate MTs, neither by gene structure, protein similarity nor metal-binding behavior of the encoded peptides. The closest relative is the echinoderm MT, which confirm proposed phylogenetic relationships between these two groups. The current findings support the existence in most organisms of two types of MTs as for their metal binding preferences, devoted to different biological functions: multivalent MTs for housekeeping roles, and specialized MTs that evolve

  6. METALert - an emergency response system for China for heavy metals in the environment

    Science.gov (United States)

    Joris, Ingeborg; Seuntjens, Piet; Dams, Jef; Desmet, Nele; Van Looy, Stijn; Raymaekers, Jens; Decorte, Lieve; Raben, Ingrid; Thijssen, Chris; Zhang, Hongzhen; Dong, Jingqi; Zhang, Qianwen

    2016-04-01

    The rapid industrialisation and economic growth of China has resulted in a mirrored increase of environmental issues and threats, which make the updating of the current environmental emergency response protocols very important. Heavy metal pollution accidents with high environmental risks are happening more frequently than ever in recent years. Despite efforts made by the authorites in respect to the formulation of sound policy, efficient technical methods and regulations for dealing with appropriate responses to emergency environmental incidents related to heavy metal pollution are still lacking. METALert is a generic Emergency Response System (ERS) for accidental pollution incidents caused by key heavy metal related industries in China and developed to support China in achieving its environmental targets. The METALert tool is based on environmental models for forecasting, simulation and visualisation of dispersion of heavy metal pollution in water, air and soil. The tool contains a generic database with scenarios for accidental release of metals in typical accidents related to the five key heavy metal industries in China. The tool can calculate the impact of an accident in water, air and soil and is evaluated and demonstrated for a river basin in the Chenzhou area, an important heavy metal mining area in China. The setup of the tool, the background models and the application in Chenzhou will be presented.

  7. Responses of Plant Proteins to Heavy Metal Stress—A Review

    Directory of Open Access Journals (Sweden)

    Md. Kamrul Hasan

    2017-09-01

    Full Text Available Plants respond to environmental pollutants such as heavy metal(s by triggering the expression of genes that encode proteins involved in stress response. Toxic metal ions profoundly affect the cellular protein homeostasis by interfering with the folding process and aggregation of nascent or non-native proteins leading to decreased cell viability. However, plants possess a range of ubiquitous cellular surveillance systems that enable them to efficiently detoxify heavy metals toward enhanced tolerance to metal stress. As proteins constitute the major workhorses of living cells, the chelation of metal ions in cytosol with phytochelatins and metallothioneins followed by compartmentalization of metals in the vacuoles as well as the repair of stress-damaged proteins or removal and degradation of proteins that fail to achieve their native conformations are critical for plant tolerance to heavy metal stress. In this review, we provide a broad overview of recent advances in cellular protein research with regards to heavy metal tolerance in plants. We also discuss how plants maintain functional and healthy proteomes for survival under such capricious surroundings.

  8. modelling of responses from orthogonal metal cutting of mild steel ...

    African Journals Online (AJOL)

    user

    representative sample range from mechanical shafts to fasteners, screws and hydraulic jack. ... A fifteen-run based Box-Behnken response surface design was created using widely ...... Genetic Algorithm Approach for Optimisation of Surface.

  9. Protein-responsive assemblies from catechol-metal ion supramolecular coordination.

    Science.gov (United States)

    Yuan, C; Chen, J; Yu, S; Chang, Y; Mao, J; Xu, Y; Luo, W; Zeng, B; Dai, L

    2015-03-21

    Supramolecular self-assembly driven by catechol-metal ion coordination has gained great success in the fabrication of functional materials including adhesives, capsules, coatings and hydrogels. However, this route has encountered a great challenge in the construction of nanoarchitectures in the absence of removable templates, because of the uncontrollable crosslinking of catechol-metal ion coordination. Herein, we show that a supramolecular approach, combining both catechol-metal ion coordination and polymer self-assembly together, can organize polymers into hybrid nanoassemblies ranging from solid particles, homogeneous vesicles to Janus vesicles. Without the introduction of a specific binding ligand or complicated molecular design, these assemblies can totally disassemble in response to proteins. UV/vis absorption, fluorescence quenching and recovery investigations have confirmed that proteins can seize metal ions from the hybrid nanoassemblies, thus causing the degradation of catechol-metal ion coordination networks.

  10. Planarians in toxicology. Responses of asexual Dugesia dorotocephala to selected metals

    Energy Technology Data Exchange (ETDEWEB)

    Kapu, M.M.; Schaeffer, D.J. (Univ. of Illinois, Urbana (United States))

    1991-08-01

    The planarian Dugesia dorotocephala is a freshwater invertebrate found in unpolluted flowing surface waters. Planarians have a sensitive nervous system with synapses and true brain and evidence these in a variety of social and response behaviors. The inclusion of planarians in a screening battery would provide improved sensitivity in detecting toxicity because planarians commonly respond to lower levels of contamination than do other species. Numerous toxicity test have been conducted to determine the acute and chronic effects of toxicants to provide data necessary for the development of water quality criteria. The appropriateness of Illinois water quality standards for metals was investigated using a 1-hr behavioral test based on the responses of the planarian D. dorotocephala. One possible difficulty with water quality standards for metals is that the standard for each metal is usually established without regard to the effects of other metals present in the receiving water.

  11. Self-Sufficient Healthcare Logistics Systems and Responsiveness: Ten Cases of Foreign Field Hospitals Deployed to Disaster Relief Supply Chains

    Directory of Open Access Journals (Sweden)

    Michael Naor

    2016-06-01

    Full Text Available Recent disasters around the globe illustrate the unpredictability of their timing and the severity of their impact, making aid operations highly uncertain and complex. The aftermath of sudden-impact disasters, such as civil conflicts, wars, and natural disasters, are typically characterized by chaos and the urgent need for medical care for a massive number of casualties; however, damage to local healthcare infrastructures usually render them unable to deliver needed services. Foreign field hospitals, innovative self-sufficient emergency healthcare logistics systems deployed outside the hospitals’ country, constitute a temporary solution until the local facilities are repaired or rebuilt. These types of healthcare logistics system have been deployed with great success. However, not much is known about factors that may account for their success in the supply chain literature. In this study, we investigate military foreign field hospitals and explore general factors that may account for their effectiveness. Specifically, we look into military healthcare logistics systems, specifically foreign field hospitals (FFHs, to explore factors that may account for their responsiveness. We examine ten successful deployments of an experienced and effective military FFH through an exploratory case analysis to shed light into factors that may account for its success. Various propositions and avenues for future research are developed.

  12. Polychaete response to fresh food supply at organically enriched coastal sites: Repercussion on bioturbation potential and trophic structure

    Science.gov (United States)

    Venturini, N.; Pires-Vanin, A. M. S.; Salhi, M.; Bessonart, M.; Muniz, P.

    2011-12-01

    We investigated the vertical distribution, abundance, specific and functional structure of polychaete assemblages at four organically enriched sites. The effects of fresh organic matter input from the water column driving by upwelling were evaluated. Temperature and salinity values indicate the intrusion of South Atlantic Central Water (SACW) in spring, a nutrient-rich water mass. The dominance of the conveyor belt transport (CONV) in the station influenced by SACW, in the spring survey, is associated with fresh organic matter input as indicated by higher amounts of polyunsaturated fatty acids. Conversely, the predominance of the diffusive mixing (DIFF) bioturbation category, in the sites without SACW influence is related to the preferential accumulation of more refractive food resources as indicated by higher concentrations of short chain saturated fatty acids. At the site influenced by SACW, the changes in polychaete assemblages were not all evident during proceeding upwelling conditions, but may persist at the end of the upwelling. Polychaetes in the study area seemed to be limited by the quality but not the quantity of food. The delay in polychaete response to fresh food supply may be related to the organic enrichment and the prevalence of refractory material in the sediments.

  13. Stimuli-Responsive DNA-Functionalized Metal-Organic Frameworks (MOFs).

    Science.gov (United States)

    Kahn, Jason S; Freage, Lina; Enkin, Natalie; Garcia, Miguel Angel Aleman; Willner, Itamar

    2017-02-01

    The synthesis of nucleic acid-functionalized metal-organic frameworks (MOFs) is described. The metal-organic frameworks are loaded with a dye being locked in the structures by means of stimuli-responsive nucleic acid caps. The pH and K(+) -ion-triggered release, and switchable release, are demonstrated. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Metal-responsive promoter DNA compaction by the ferric uptake regulator

    OpenAIRE

    Roncarati, Davide; Pelliciari, Simone; Doniselli, Nicola; Maggi, Stefano; Vannini, Andrea; Valzania, Luca; Mazzei, Luca; Zambelli, Barbara; Rivetti, Claudio; Danielli, Alberto

    2016-01-01

    Short-range DNA looping has been proposed to affect promoter activity in many bacterial species and operator configurations, but only few examples have been experimentally investigated in molecular detail. Here we present evidence for a metal-responsive DNA condensation mechanism controlled by the Helicobacter pylori ferric uptake regulator (Fur), an orthologue of the widespread Fur family of prokaryotic metal-dependent regulators. H. pylori Fur represses the transcription of the essential ar...

  15. Contribution of Proteomic Studies Towards Understanding Plant Heavy Metal Stress Response

    Directory of Open Access Journals (Sweden)

    Zahed eHossain

    2013-01-01

    Full Text Available Modulation of plant proteome composition is an inevitable process to cope with the environmental challenges including heavy metal stress. Soil and water contaminated with hazardous metals not only cause permanent and irreversible health problems, but also result substantial reduction in crop yields. In course of time, plants have evolved complex mechanisms to regulate the uptake, mobilization and intracellular concentration of metal ions to alleviate the stress damages. Since, the functional translated portion of the genome plays an essential role in plant stress response, proteomic studies provide us a finer picture of protein networks and metabolic pathways primarily involved in cellular detoxification and tolerance mechanism. In the present review, an attempt is made to present the state of the art of recent development in proteomic techniques and significant contributions made so far for better understanding the complex mechanism of plant metal stress acclimation. Role of metal stress related proteins involved in antioxidant defense system and primary metabolism is critically reviewed to get a bird’s-eye view on the different strategies of plants to detoxify heavy metals. In addition to the advantages and disadvantages of different proteomic methodologies, future applications of proteome study of subcellular organelles are also discussed to get the new insights into the plant cell response to heavy metals.

  16. Multimodality Imaging of the Long-term Vascular Responses Following Implantation of Metallic and Bioresorbable Devices

    OpenAIRE

    Gkogkas, Vasileios

    2014-01-01

    markdownabstract__Abstract__ The pattern of vascular responses following stent/scaffold implantation in conventional interventional practice has been assessed by coronary angiography, intravascular ultrasound or optical coherence tomography and manifests as in-stent vascular response (focal or diffuse) or as edge vascular response (EVR) at the transition zones (focal). The utilization of bioresorbable scaffolds made of biodegradable polymers or biocorrodible metals for coronary revacularizati...

  17. Performance of piglets in response to the standardized ileal digestible phenylalanine and tyrosine supply in low-protein diets.

    Science.gov (United States)

    Gloaguen, M; Le Floc'h, N; Primot, Y; Corrent, E; van Milgen, J

    2014-09-01

    Reducing the CP level of the diet allows for a reduction in N excretion without limiting performance as long as the amino acid (AA) requirements are covered. The availability of crystalline AA has permitted for a considerable reduction in the CP level of diets, practically used in pig nutrition. The adoption of low CP diets and the extent to which the CP content can be reduced further depends on the knowledge of the minimum levels of indispensable AA that maximize growth. The standardized ileal digestible (SID) Phe : Lys and Tyr : Lys requirements and the possibility to substitute Tyr by Phe have never been studied in piglets. The objectives of this study were to estimate these requirements in 10 to 20 kg pig as well as to determine the extent to which Phe can be used to cover the Tyr requirement. In three dose-response studies, six pigs within each of 14 blocks were assigned to six low CP diets (14.5% CP) sub-limiting in Lys at 1.00% SID. In experiment 1, the SID Phe : Lys requirement estimate was assessed by supplementing a Phe-deficient diet with different levels of l-Phe to attain 33%, 39%, 46%, 52%, 58%, and 65% SID Phe : Lys. Because Phe can be used for Tyr synthesis, the diets provided a sufficient Tyr supply. A similar approach was used in experiment 2 with six levels of l-Tyr supplementation to attain 21%, 27%, 33%, 39%, 45% and 52% SID Tyr : Lys. Phenylalanine was supplied at a level sufficient to sustain maximum growth (estimated in experiment 1). The SID Phe : Lys and SID Tyr : Lys requirements for maximizing daily gain were 54% and 40% using a curvilinear-plateau model, respectively. A 10% deficiency in Phe and Tyr reduced daily gain by 3.0% and 0.7%, respectively. In experiment 3, the effect of the equimolar substitution of dietary SID Tyr by Phe to obtain 50%, 57%, and 64% SID Phe : (Phe+Tyr) was studied at two limiting levels of Phe+Tyr. From 57% to 64% SID Phe : (Phe+Tyr), performance was slightly reduced. In conclusion, it is recommended not to

  18. Effect of metal coordination on photocurrent response properties of a tetrathiafulvalene organogel film.

    Science.gov (United States)

    Ji, Shu-Fang; Sun, Yong-Gang; Huo, Peng; Shen, Wei-Chun; Huang, Yu-De; Zhu, Qin-Yu; Dai, Jie

    2014-04-07

    Organic low molecular weight gelators with a tetrathiafulvalene (TTF) unit have received considerable attention because the formed gels usually exhibit redox active response and conducting or semiconducting properties. However, to our knowledge, metal coordination systems have not been reported for TTF-derived gels up to date. We have designed and synthesized a series of TTF derivatives with a diamide-diamino moiety that can coordinate to specific metal ions with square coordination geometry. Gelation properties and morphologies of the films prepared by the gelators in different hydrophobic solvents are characterized. The TTF derivative with a dodecyl group shows effective gelation properties, and electrodes with the organogel films are prepared. The effect of the Ni(II) and Cu(II) coordination on the photocurrent response property of the electrodes is examined. The metal square coordination significantly increases the photocurrent response. This gel system is the first metal coordination related TTF-gel-based photoelectric material. The mechanism of the metal coordination-improved photocurrent response property is discussed based on the crystal structural analysis and theoretical calculations.

  19. Earthquake Response of Reinforced Concrete Building Retrofitted with Geopolymer Concrete and X-shaped Metallic Damper

    Science.gov (United States)

    Madheswaran, C. K.; Prakash vel, J.; Sathishkumar, K.; Rao, G. V. Rama

    2017-06-01

    A three-storey half scale reinforced concrete (RC) building is fixed with X-shaped metallic damper at the ground floor level, is designed and fabricated to study its seismic response characteristics. Experimental studies are carried out using the (4 m × 4 m) tri-axial shake-table facility to evaluate the seismic response of a retrofitted RC building with open ground storey (OGS) structure using yielding type X-shaped metallic dampers (also called as Added Damping and Stiffness-ADAS elements) and repairing the damaged ground storey columns using geopolymer concrete composites. This elasto-plastic device is normally incorporated within the frame structure between adjacent floors through chevron bracing, so that they efficiently enhance the overall energy dissipation ability of the seismically deficient frame structure under earthquake loading. Free vibration tests on RC building without and with yielding type X-shaped metallic damper is carried out. The natural frequencies and mode shapes of RC building without and with yielding type X-shaped metallic damper are determined. The retrofitted reinforced concrete building is subjected to earthquake excitations and the response from the structure is recorded. This work discusses the preparation of test specimen, experimental set-up, instrumentation, method of testing of RC building and the response of the structure. The metallic damper reduces the time period of the structure and displacement demands on the OGS columns of the structure. Nonlinear time history analysis is performed using structural analysis package, SAP2000.

  20. Nodule Formation and Development in Soybeans (Glycine max L.) in Response to Phosphorus Supply in Solution Culture

    Institute of Scientific and Technical Information of China (English)

    MIAO Shu-Jie; QIAO Yun-Fa; HAN Xiao-Zeng; M. AN

    2007-01-01

    Phosphorus (P) is necessary for growth and nitrogen fixation, and thus its deficiency is a major factor limiting legume production in most agricultural soils. The effect of phosphorus supply on nodule development and its role in soybeans (Glycine max L.) was studied in a nutrient solution. Plants were inoculated with Bradyrhizobium japonicum and grown for 35 days in a glasshouse at a day and night temperature of 25 ℃ and 15 ℃, respectively. Although increasing P supply increased the concentrations of P and N in the shoots and roots, the external P supply did not significantly affect the P concentration in the nodules, and the N fixed per unit nodule biomass decreased with increasing P supply. The nitrogen content in the shoots correlated well with the P content (r = 0.92**). At an inoculation level of 102 cells mL-1, the P supply did not affect the number of nodules; however, at inoculation levels of 103.5 and 105 cells mL-1, increasing P supply increased both the number and size of nodules. Irrespective of the inoculation level, increasing P supply increased the nodule biomass relative to the biomass of the host plant. It is suggested that the P deficiency specifically inhibited the nodule development and thereby the total N2 fixation.

  1. Phytoplankton responses to atmospheric metal deposition in the coastal and open-ocean Sargasso Sea.

    Science.gov (United States)

    Mackey, Katherine R M; Buck, Kristen N; Casey, John R; Cid, Abigail; Lomas, Michael W; Sohrin, Yoshiki; Paytan, Adina

    2012-01-01

    This study investigated the impact of atmospheric metal deposition on natural phytoplankton communities at open-ocean and coastal sites in the Sargasso Sea during the spring bloom. Locally collected aerosols with different metal contents were added to natural phytoplankton assemblages from each site, and changes in nitrate, dissolved metal concentration, and phytoplankton abundance and carbon content were monitored. Addition of aerosol doubled the concentrations of cadmium (Cd), cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), and nickel (Ni) in the incubation water. Over the 3-day experiments, greater drawdown of dissolved metals occurred in the open ocean water, whereas little metal drawdown occurred in the coastal water. Two populations of picoeukaryotic algae and Synechococcus grew in response to aerosol additions in both experiments. Particulate organic carbon increased and was most sensitive to changes in picoeukaryote abundance. Phytoplankton community composition differed depending on the chemistry of the aerosol added. Enrichment with aerosol that had higher metal content led to a 10-fold increase in Synechococcus abundance in the oceanic experiment but not in the coastal experiment. Enrichment of aerosol-derived Co, Mn, and Ni were particularly enhanced in the oceanic experiment, suggesting the Synechococcus population may have been fertilized by these aerosol metals. Cu-binding ligand concentrations were in excess of dissolved Cu in both experiments, and increased with aerosol additions. Bioavailable free hydrated Cu(2+) concentrations were below toxicity thresholds throughout both experiments. These experiments show (1) atmospheric deposition contributes biologically important metals to seawater, (2) these metals are consumed over time scales commensurate with cell growth, and (3) growth responses can differ between distinct Synechococcus or eukaryotic algal populations despite their relatively close geographic proximity and taxonomic similarity.

  2. Phytoplankton responses to atmospheric metal deposition in the coastal and open-ocean Sargasso Sea

    Directory of Open Access Journals (Sweden)

    Katherine Rose Marie Mackey

    2012-10-01

    Full Text Available This study investigated the impact of atmospheric metal deposition on natural phytoplankton communities at open-ocean and coastal sites in the Sargasso Sea during the spring bloom. Locally collected aerosols with different metal contents were added to natural phytoplankton assemblages from each site, and changes in nitrate, dissolved metal concentration, and phytoplankton abundance and carbon content were monitored. Addition of aerosol doubled the concentrations of cadmium, cobalt, copper, iron, manganese and nickel in the incubation water. Over the three-day experiments, greater drawdown of dissolved metals occurred in the open ocean water, whereas little metal drawdown occurred in the coastal water. Two populations of picoeukaryotic algae and Synechococcus grew in response to aerosol additions in both experiments. Particulate organic carbon (POC increased and was most sensitive to changes in picoeukaryote abundance. Phytoplankton community composition differed depending on the chemistry of the aerosol added. Enrichment with aerosol that had higher metal content led to a 10-fold increase in Synechococcus abundance in the oceanic experiment but not in the coastal experiment. Enrichment of aerosol-derived cobalt (Co, manganese, and nickel were particularly enhanced in the oceanic experiment, suggesting the Synechococcus population may have been fertilized by these aerosol metals. Copper (Cu-binding ligand concentrations were in excess of dissolved Cu in both experiments, and increased with aerosol additions. Bioavailable free hydrated Cu2+ concentrations were below toxicity thresholds throughout both experiments. These experiments show (1 atmospheric deposition contributes biologically important metals to seawater, (2 these metals are consumed over time scales commensurate with cell growth, and (3 growth responses can differ between distinct Synechococcus or eukaryotic algal populations despite relatively close geographic proximity and taxonomic

  3. Governmental guarantee responsibility and the provision of security of connection and supply in the energy sector.; Staatliche Gewaehrleistungsverantwortung und die Sicherstellung von Anschluss und Versorgung im Bereich der Energiewirtschaft

    Energy Technology Data Exchange (ETDEWEB)

    Schiller, Marcus

    2012-07-01

    The present study is confined to an investigation of the regulations of the Energy Economy Law regarding connection and supply. Other possible contractual claims pursuant to Art. 826 of the German Civil Code or the prohibition of monopoly abuse under anti-trust law are only addressed cursorily on account of their low practical relevance to household customers' supply connection and energy supply. The study comes to the conclusion that the provisions of the Energy Economy Law (EnWG) on final consumers' supply connection and energy supply sufficiently implement the state's guarantee responsibility in energy supply matters as required by welfare state principles. The author argues that the state's guarantee responsibility primarily obliges it to ensure an energy supply that is available to everyone at an affordable price at any time and any place. These requirements are met by the regulations on supply connection and energy supply contained in Articles 17 f. and 36 ff. EnWG. A coherent regulatory system on connection and supply is established in particular by the provisions of Art. 18 EnWG on the general connection obligation and of Art. 36 EnWG on the basic supply obligation. This system secures the supply of final consumers with grid-bound energy even under the present altered framework conditions, meaning the compulsory separation of connection and supply, and does so to the constitutionally required extent.

  4. Root responses and metal accumulation in two contrasting ecotypes of Sedum alfredii Hance under lead and zinc toxic stress.

    Science.gov (United States)

    Li, Ting-Qiang; Yang, Xiao-E; Jin, Xiao-Fen; He, Zhen-Li; Stoffella, Peter-J; Hu, Qing-Hua

    2005-01-01

    Sedum alfredii Hance has been reported to be a Zn-hyperaccumulator plant species. In this study, root morphological and physiological response of the hyperaccumulating ecotype of S. alfredii H. (HE) from the mined area and the non-hyperaccumulating ecotype of S. alfredii H. (NHE) from the agricultural area to supplied levels of Zn and Pb were investigated. The results showed that Zn concentrations in the leaves and the stems of the HE were 34 and 41 times higher, whereas lead concentrations were 1.9 and 2.4 times greater, respectively, than those of the NHE when grown at 1224 microM Zn and/or 200 microM Pb. At combined supply of 1224 microM Zn with 200 microM Pb, however, zinc concentrations in the stems and leaves of the, HE decreased, while lead concentrations in the stems increased significantly, as compared with those of single metal treatment. Lead uptake of the HE was enhanced by Zn addition. Root activity of the HE decreased by Pb treatment in the first two days, but recovered afterward and close to the control at day 10 of the treatment. However, root activity of the NHE decreased by each metal treatment, and was not recovered with the advance of treatment time. Root length, root surface area, and root volumes increased obviously due to Zn and/or Pb/Zn combined treatments for the HE, but significantly decreased due to Pb, Zn, or Pb/Zn combined treatment for the NHE. Zinc and Pb concentrations in both ecotypes of S. alfredii H. were positively correlated with root length, root surface area, and root volumes. Root exudates of the HE, especially treated with Zn, increased the extractability of Pb and Zn from the mined soil. At the Zn supply level of 1224microM, the extractability of root exudates on soil Pb was 3-12 times greater for the HE than for the NHE. These results imply that the tolerance and hyperaccumulation of the hyperaccumulating ecotype of S. alfredii H. to Zn and Pb appear to be closely related to its high adaptation of root growth, morphology

  5. Phenotypic plasticity in Scenedesmus incrassatulus (Chlorophyceae) in response to heavy metals stress.

    Science.gov (United States)

    Peña-Castro, Julián Mario; Martínez-Jerónimo, Fernando; Esparza-García, Fernando; Cañizares-Villanueva, Rosa Olivia

    2004-12-01

    The microalgae genus Scenedesmus is commonly found in freshwater bodies, wastewater facilities and water polluted with heavy metals. Phenotypic plasticity in Scenedesmus has been documented in response to a wide variety of conditions; however, heavy metals have not been comprehensively documented as phenotypic plasticity inducers. In this study, we report the phenotypic plasticity of Scenedesmus incrassatulus (a non-spiny, four-cell coenobium forming species) in response to EC(50) value of copper, cadmium and hexavalent chromium. S. incrassatulus was grown in batch cultures in the presence of each metal. Chlorophyll-a content, cell size, parameters derived from the schematic energy-flux model for photosystem II, and morphotype expressions were recorded. Divalent cation metals induced unicellular forms, and hexavalent chromium produced out-of-shape coenobia corresponding to various stages of autospore formation. The changes induced by divalent metals were interpreted as phenotypic plasticity, because they were always associated to population doublings and were reversible when toxicant pressure was removed (only for Cu). Copper was the best inductor of unicellular forms and also affected significantly all the photosynthetic parameters measured. The developed morphotypes could confer ecological advantages to S. incrassatulus in metal stressed environments.

  6. An Agri-Food Supply Chain Model to Enhance the Business Skills of Small-Scale Farmers Using Corporate Social Responsibility

    Directory of Open Access Journals (Sweden)

    Wahyudi Sutopo

    2012-05-01

    Full Text Available In general, small-scale vegetable farmers experience problems in improving the safety and quality of vegetables for supplying high-class consumers in modern retailers. Farmer Group and/or Cooperative (FGC should be able to assist its members to meet the relevant provisions of modern retail on product specifications, delivery terms, and internal business requirements. This study proposed an agri-food supply chain (ASC model that involves the corporate social responsibility (CSR activities to enhance the business skills of the FGC as supplier of modern retailer. Multi-objective optimization programming is developed to determine the amount and timing of supply, level of farmers training skills, quality improvement target, and the CSR total cost. The results show that the proposed model can be used to determine the priority of programs in order to empower farmers' groups as modern retail suppliers.

  7. Phytoremediation of heavy metals by Alternanthera bettzickiana: Growth and physiological response.

    Science.gov (United States)

    Tauqeer, Hafiz Muhammad; Ali, Shafaqat; Rizwan, Muhammad; Ali, Qasim; Saeed, Rashid; Iftikhar, Usman; Ahmad, Rehan; Farid, Mujahid; Abbasi, Ghulam Hassan

    2016-04-01

    The present study was aimed to evaluate the morphological, physiological and biochemical responses of Alternanthera Bettzickiana (Regel) G. Nicholson plant subjected to different levels of cadmium (Cd) and lead (Pb) (0, 0.5, 1.0 and 2.0 mM) stress. A. bettzickiana was able to accumulate Cd and Pb in different plant parts and total uptake of both metals was higher in shoots than roots. Plant growth, biomass and photosynthetic pigments increased with increasing metal concentrations, up to 1.0 mM, in soil and then decreased with higher metal levels. The activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) increased under lower metal levels (0.5 and 1.0 mM) while decreased at higher metal levels (2.0 mM). Leaf and root electrolyte leakage (EL), malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents decreased at lower metal levels (≤1.0 mM) while increased at higher levels. The present study clearly signifies the potential of A. bettzickiana plant towards Cd and Pb tolerance and accumulation especially at lower metal levels. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Marsh plant response to metals: Exudation of aliphatic low molecular weight organic acids (ALMWOAs)

    Science.gov (United States)

    Rocha, A. Cristina S.; Almeida, C. Marisa R.; Basto, M. Clara P.; Vasconcelos, M. Teresa S. D.

    2016-03-01

    Metal exposure is known to induce the production and secretion of substances, such as aliphatic low molecular weight organic acids (ALMWOAs), into the rhizosphere by plant roots. Knowledge on this matter is extensive for soil plants but still considerably scarce regarding marsh plants roots adapted to high salinity media. Phragmites australis and Halimione portulacoides, two marsh plants commonly distributed in European estuarine salt marshes, were used to assess the response of roots of both species, in terms of ALMWOAs exudation, to Cu, Ni and Cd exposure (isolated and in mixture since in natural environment, they are exposed to mixture of metals). As previous studies were carried out in unrealistic and synthetic media, here a more natural medium was selected. Therefore, in vitro experiments were carried out, with specimens of both marsh plants, and in freshwater contaminated with two different Cu, Ni and Cd concentrations (individual metal and in mixture). Both marsh plants were capable of liberating ALMWOAs into the surrounding medium. Oxalic, citric and maleic acids were found in P. australis root exudate solutions and oxalic and maleic acids in H. portulacoides root exudate solutions. ALMWOA liberation by both plants was plant species and metal-dependent. For instance, Cu affected the exudation of oxalic acid by H. portulacoides and of oxalic and citric acids by P. australis roots. In contrast, Ni and Cd did not stimulate any specific response. Regarding the combination of all metals, H. portulacoides showed a similar response to that observed for Cu individually. However, in the P. australis case, at high metal concentration mixture, a synergetic effect led to the increase of oxalic acid levels in root exudate solution and to a decrease of citric acid liberation. A correlation between ALMWOAs exudation and metal accumulation could not be established. P. australis and H. portulacoides are considered suitable metal phytoremediators of estuarine impacted areas

  9. Ab initio phonon coupling and optical response of hot electrons in plasmonic metals

    CERN Document Server

    Brown, Ana M; Narang, Prineha; Goddard, William A; Atwater, Harry A

    2016-01-01

    Ultrafast laser measurements probe the non-equilibrium dynamics of excited electrons in metals with increasing temporal resolution. Electronic structure calculations can provide a detailed microscopic understanding of hot electron dynamics, but a parameter-free description of pump-probe measurements has not yet been possible, despite intensive research, because of the phenomenological treatment of electron-phonon interactions. We present ab initio predictions of the electron-temperature dependent heat capacities and electron-phonon coupling coefficients of plasmonic metals. We find substantial differences from free-electron and semi-empirical estimates, especially in noble metals above transient electron temperatures of 2000 K, because of the previously-neglected strong dependence of electron-phonon matrix elements on electron energy. We also present first-principles calculations of the electron-temperature dependent dielectric response of hot electrons in plasmonic metals, including direct interband and phon...

  10. Growth Responses of Fish During Chronic Exposure of Metal Mixture under Laboratory Conditions

    Directory of Open Access Journals (Sweden)

    Saima Naz and Muhammad Javed

    2013-07-01

    Full Text Available Growth responses of five fish species viz. Catla catla, Labeo rohita, Cirrhina mrigala, Ctenopharyngodon idella and Hypophthalmichthys molitrix were determined, separately, under chronic exposure of binary mixture of metals (Zn+Ni at sub-lethal concentrations (1/3rd of LC50 for 12 weeks. Randomized complete block design (RCBD was followed to conduct this research work. The groups (10 fish each of Catla catla, Labeo rohita, Cirrhina mrigala, Ctenopharyngodon idella and Hypophthalmichthys molitrix having almost similar weights were investigated for their growth responses and metals bioaccumulation patterns in their body organs during chronic exposure of Zn+Ni mixture. The bioaccumulation of metals in the fish body organs viz. gills, liver, kidney, fins, bones, muscle and skin were also determined before and after growth trails under the stress of metals mixture. The exposure of fish to sub-lethal concentrations of mixture caused significant impacts on the average wet weight increments of five fish species. Ctenopharyngodon idella and Labeo rohita attained significantly higher weights, followed by that of Hypophthalmichthys molitrix, Cirrhina mrigala and Catla catla. However, the growth of metals mixture exposed fish species was significantly lesser than that of control fish (un-stressed. Significantly variable condition factor values reflected the degree of fish well-beings that correlated directly with fish growth and metal exposure concentration. Any significant change in feed intake, due to stress, is reflected in terms of fish growth showing the impacts of metal mixture on fish growth were either additive or antagonist / synergistic. Accumulation of all the metals in fish body followed the general order: liver>kidney>gills> skin >muscle> fins >bones.

  11. Photoluminescence response of colloidal quantum dots on VO2 film across metal to insulator transition.

    Science.gov (United States)

    Kuznetsov, Sergey N; Cheremisin, Alexander B; Stefanovich, Genrikh B

    2014-01-01

    We have proposed a method to probe metal to insulator transition in VO2 measuring photoluminescence response of colloidal quantum dots deposited on the VO2 film. In addition to linear luminescence intensity decrease with temperature that is well known for quantum dots, temperature ranges with enhanced photoluminescence changes have been found during phase transition in the oxide. Corresponding temperature derived from luminescence dependence on temperature closely correlates with that from resistance measurement during heating. The supporting reflectance data point out that photoluminescence response mimics a reflectance change in VO2 across metal to insulator transition. Time-resolved photoluminescence study did not reveal any significant change of luminescence lifetime of deposited quantum dots under metal to insulator transition. It is a strong argument in favor of the proposed explanation based on the reflectance data. 71.30. + h; 73.21.La; 78.47.jd.

  12. Responses of a soil bacterium, Pseudomonas chlororaphis O6 to commercial metal oxide nanoparticles compared with responses to metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Dimkpa, Christian O., E-mail: cdimkpa@usu.edu [Department of Biological Engineering, Utah State University, Logan, UT 84322 (United States); Calder, Alyssa; Britt, David W. [Department of Biological Engineering, Utah State University, Logan, UT 84322 (United States); McLean, Joan E. [Utah Water Research Laboratory, Utah State University, Logan, UT 84322 (United States); Anderson, Anne J. [Department of Biology, Utah State University, Logan, UT 84322 (United States)

    2011-07-15

    The toxicity of commercially-available CuO and ZnO nanoparticles (NPs) to pathogenic bacteria was compared for a beneficial rhizosphere isolate, Pseudomonas chlororaphis O6. The NPs aggregated, released ions to different extents under the conditions used for bacterial exposure, and associated with bacterial cell surface. Bacterial surface charge was neutralized by NPs, dependent on pH. The CuO NPs were more toxic than the ZnO NPs. The negative surface charge on colloids of extracellular polymeric substances (EPS) was reduced by Cu ions but not by CuO NPs; the EPS protected cells from CuO NPs-toxicity. CuO NPs-toxicity was eliminated by a Cu ion chelator, suggesting that ion release was involved. Neither NPs released alkaline phosphatase from the cells' periplasm, indicating minimal outer membrane damage. Accumulation of intracellular reactive oxygen species was correlated with CuO NPs lethality. Environmental deposition of NPs could create niches for ion release, with impacts on susceptible soil microbes. - Highlights: > Toxicity of metallic nanoparticles (NPs) was evaluated in a beneficial bacterium, Pseudomonas chlororaphis O6 (PcO6). > Aggregated commercial CuO and ZnO NPs released Cu and Zn ions and changed bacterial surface charge, depending on pH. > The NPs were toxic to PcO6 through NP-specific, but also ion release mechanisms. > Reactive oxygen species were produced by CuO NP and Cu ion at lethal concentrations, but bacterial EPS protected against Cu. > The periplasmic marker, alkaline phosphate, activity was increased by the NPs and ions. - Aggregated CuO and ZnO nanoparticles release ions and cause different toxicities in a beneficial soil bacterium.

  13. Antioxidative Responses and Metal Accumulation in Invasive Plant Species Growing on Mine Tailings in Zanjan, Iran

    Institute of Scientific and Technical Information of China (English)

    M. M. A. BOO JAR; Z. TAVAKKOLI

    2011-01-01

    Tailings of a Pb and Zn mine as a metal-contaminated area (Zone 1) with two pioneer plant species,Peganum harmala and Zygophyllum fabago,were investigated and compared with a non-contaminated area (Zone 2) in the vicinity.Total concentrations of Pb,Zn,and Cu in the soil of Zone 1 were 1 416,2217,and 426 mg kg-1,respectively,and all exceeded their ranges in the normal soils.The soil pH was in the neutral range and most of the physical and chemical characteristics of the soils from both zones were almost similar.The species Z.fabago accumulated higher Cu and Zn in its aerial part and roots than the normal plants.On the other.hand,their concentrations did not reach the criteria that the species could be considered as a metal hyperaccumulator.The species P.harmala did not absorb metals in its roots; accordingly,the accumulation factor values of these metals were lower than 1.The contents of chlorophyll,biomass,malondialdehyde,and dityrosine in these two species did not vary significantly between the two zones studied.In Zone 1,leaf vacuoles of Z.fabago stored 35.6% and 43.2% of the total leaf Cu and Zn,respectively.However,in this species,the levels of phytochelatins (PCs) and glutathione (GSH) and antioxidant enzyme activities were significantly higher in Zone 1 than in Zone 2.In conclusion,metal exclusion in P.harmala and metal accumulation in Z.fabago were the basic strategies in the two studied pioneer species growing on the metal-contaminated zone.In response to metal stress,elevation in antioxidant enzyme activities,increases in the PCs and GSH levels in the aerial parts,and metal storage within vacuoles counteracted each other in the invasion mechanism of Z.fabago.

  14. Great tit response to decreasing industrial heavy metal emissions.

    Science.gov (United States)

    Costa, R A; Gomes, T; Eira, C; Vaqueiro, J; Vingada, J V

    2017-08-01

    This study evaluated the effects of environmental pollution on decreasing great tit (Parus major) breeding parameters in an industrial area in the west coast of Portugal. Several great tit breeding parameters were monitored in the industrial area, as well as in a rural area not affected by industrial emissions. Low levels of air pollution in both industrial and rural areas were confirmed by assessing trace element concentrations in pine needles. Concentrations of Cd and Hg in pine needles from the industrial area (Cd = 0.05 ppm; Hg = 0.005 ppm) were significantly lower than those found in needles collected from the reference area (Cd = 0.07 ppm; Hg = 0.007 ppm). Additionally, the breeding success of great tits increased in the industrial area in comparison to the reference area (0.93 ± 0.08 and 0.62 ± 0.22, respectively). The changes on great tit breeding parameters were probably related with changes in the breeding density of other competitive species, together with a decreasing frass-fall biomass. Further long-term ecological studies in industrial areas are necessary to understand the changing breeding performance and strategies used by great tits in response to pollution shifts in the environment.

  15. Adaptive phenotypic plasticity of Pseudoroegneria spicata: response of stomatal density, leaf area and biomass to changes in water supply and increased temperature

    Science.gov (United States)

    Fraser, Lauchlan H.; Greenall, Amber; Carlyle, Cameron; Turkington, Roy; Friedman, Cynthia Ross

    2009-01-01

    Background and Aims Changes in rainfall and temperature brought about through climate change may affect plant species distribution and community composition of grasslands. The primary objective of this study was to test how manipulation of water and temperature would influence the plasticity of stomatal density and leaf area of bluebunch wheatgrass, Pseudoroegneria spicata. It was hypothesized that: (1) an increased water supply will increase biomass and leaf area and decrease stomatal density, while a reduced water supply will cause the opposite effect; (2) an increase in temperature will reduce biomass and leaf area and increase stomatal density; and (3) the combinations of water and temperature treatments can be aligned along a stress gradient and that stomatal density will be highest at high stress. Methods The three water supply treatments were (1) ambient, (2) increased approx. 30 % more than ambient through weekly watering and (3) decreased approx. 30 % less than ambient by rain shades. The two temperature treatments were (1) ambient and (2) increased approx. 1–3 °C by using open-top chambers. At the end of the second experimental growing season, above-ground biomass was harvested, oven-dried and weighed, tillers from bluebunch wheatgrass plants sampled, and the abaxial stomatal density and leaf area of tillers were measured. Key Results The first hypothesis was partially supported – reducing water supply increased stomatal density, but increasing water supply reduced leaf area. The second hypothesis was rejected. Finally, the third hypothesis could not be fully supported – rather than a linear response there appears to be a parabolic stomatal density response to stress. Conclusions Overall, the abaxial stomatal density and leaf area of bluebunch wheatgrass were plastic in their response to water and temperature manipulations. Although bluebunch wheatgrass has the potential to adapt to changing climate, the grass is limited in its ability to respond

  16. Comparison of heat treatment response of semisolid metal processed alloys A356 and F357

    CSIR Research Space (South Africa)

    Moller, H

    2010-01-01

    Full Text Available The heat treatment response of semisolid metal high pressure die cast Al-7Si-Mg alloys A356 and F357 was studied and compared. It was found that the heat treatment behaviour of alloy F357 is influenced markedly by the stability of the Mg containing...

  17. Luminescent metal-organic framework films as highly sensitive and fast-response oxygen sensors.

    Science.gov (United States)

    Dou, Zhongshang; Yu, Jiancan; Cui, Yuanjing; Yang, Yu; Wang, Zhiyu; Yang, Deren; Qian, Guodong

    2014-04-16

    Luminescent metal-organic framework films, CPM-5⊃Tb(3+) and MIL-100(In)⊃Tb(3+), have been constructed by postfunctionalization of two porous indium-organic frameworks with different structures, respectively. The MIL-100(In)⊃Tb(3+) film shows high oxygen sensitivity (KSV = 7.59) and short response/recovery time (6 s/53 s).

  18. DIRECT SPECTRUM ANALYSIS OF ANELASTIC DEFORMATION RESPONSE DURING STRUCTURAL RELAXATION OF AMORPHOUS METALS

    NARCIS (Netherlands)

    CSACH, K; Ocelik, Vaclav; MISKUF, J; BENGUS, VZ; DUHAJ, P

    1994-01-01

    Direct relaxation time spectrum analysis method has been successfully used to observe and. to study changes in the kinetics of isothermal anelastic deformation response of soft magnetic metallic glass Fe40Ni40B20 during structural relaxation. Computed relaxation time spectra contain three or four qu

  19. Differences in metabolism between the biofilm and planktonic response to metal stress.

    Science.gov (United States)

    Booth, Sean C; Workentine, Matthew L; Wen, Jing; Shaykhutdinov, Rustem; Vogel, Hans J; Ceri, Howard; Turner, Raymond J; Weljie, Aalim M

    2011-07-01

    Bacterial biofilms are known to withstand the effects of toxic metals better than planktonic cultures of the same species. This phenomenon has been attributed to many features of the sessile lifestyle not present in free-swimming populations, but the contribution of intracellular metabolism has not been previously examined. Here, we use a combined GC-MS and (1)H NMR metabolomic approach to quantify whole-cell metabolism in biofilm and planktonic cultures of the multimetal resistant bacterium Pseudomonas fluorescens exposed to copper ions. Metabolic changes in response to metal exposure were found to be significantly different in biofilms compared to planktonic cultures. Planktonic metabolism indicated an oxidative stress response that was characterized by changes to the TCA cycle, glycolysis, pyruvate and nicotinate and niacotinamide metabolism. Similar metabolic changes were not observed in biofilms, which were instead dominated by shifts in exopolysaccharide related metabolism suggesting that metal stress in biofilms induces a protective response rather than the reactive changes observed for the planktonic cells. From these results, we conclude that differential metabolic shifts play a role in biofilm-specific multimetal resistance and tolerance. An altered metabolic response to metal toxicity represents a novel addition to a growing list of biofilm-specific mechanisms to resist environmental stress.

  20. Prioritizing Demand Response: How Federal Legislation and Technological Innovation Changed the Electricity Supply Market and the Need to Revitalize FERC Order 745

    Directory of Open Access Journals (Sweden)

    Bradley J. McAllister

    2015-08-01

    Full Text Available Traditional barriers to entry in the electricity supply marketplace are crumbling due to recent federal legislation and new technology. The Federal Energy Regulatory Commission (FERC's Order 745 prioritizes the use of demand response via a uniform pricing mechanism. Through it, demand response is able to provide the same benefit as traditional electricity generation - at a reduced cost - and improve service, reliability, and market development. Consequently, the increased use of demand response reduces prices for regional grid operators, as well as commercial, institutional, and residential consumers. This Note discusses the legal, economic, and policy reasons for upholding Order 745 in the face of transformative change in the electricity supply market and evaluates the history of smart grid legislation leading up to the issuance of Order 745 in 2011. Next, it analyzes how energy intelligence hardware and software allow new entrants into the wholesale electricity supply market in hopes of capitalizing on inefficiencies in regional power distribution and the revolutionary opportunities for residential consumers through new technologies. Most importantly, this Note argues for a reversal of the D.C. Circuit’s decision to vacate Order 745 in the case EPSA v. FERC, decided in May 2014. Such a reversal is necessary because Order 745 falls within FERC’s authority under the Federal Power Act and the loss of a uniform pricing mechanism for demand response resources sold at capacity auctions will harm electricity markets.

  1. Thermomechanical response of metal foam sandwich panels for structural thermal protection systems in hypersonic vehicles

    Science.gov (United States)

    Rakow, Joseph F.

    Sandwich panels with metal foam cores are proposed for load-bearing structural components in actively cooled thermal protection systems for aerospace vehicles. Prototype acreage metal foam sandwich panels (MFSP's) are constructed and analyzed with the central goal of characterizing the thermomechanical response of the system. MFSP's are subjected to uniform temperature fields and equibiaxial loading in a novel experimental load frame. The load frame exploits the mismatch of coefficients of thermal expansion and allows for thermostructural experimentation without the endemic conflict of thermal and mechanical boundary conditions. Back-to-back strain gages and distributed thermocouples capture the in-plane response of the panels, including buckling and elastic-plastic post-buckling. The out-of-plane response is captured via moire interferometry, which provides a visualization of evolving mode shapes throughout the post-buckling regime. The experimental results agree with an analytical prediction for critical temperatures in sandwich panels based on a Rayleigh-Ritz minimization of the energy functional for a Reissner-Mindlin plate. In addition, a three-dimensional finite element model of the non-linear thermomechanical response of the panel-frame experimental system is developed and the results are shown to agree well with the experimentally identified response of MFSP's. Central to analytical and numerical characterization of MFSP's is an understanding of the response of metal foam under shear loading. The shear response of metal foam is captured experimentally, providing density-dependent relationships for material stiffness, strength, and energy absorption. Speckle photography is employed to identify microstructural size effects in the distribution of strain throughout metal foam under shear loading. In addition, a micromechanical model is established for the density-dependent shear modulus of metal foam, which allows for the coupling of cell-level imperfections

  2. Correlation of transcriptomic responses and metal bioaccumulation in Mytilus edulis L. reveals early indicators of stress

    Energy Technology Data Exchange (ETDEWEB)

    Poynton, Helen C., E-mail: helen.poynton@umb.edu; Robinson, William E.; Blalock, Bonnie J.; Hannigan, Robyn E.

    2014-10-15

    Highlights: • Gene expression and metal tissue concentrations were compared in Mytilus edulis. • Expression levels of several transcripts correlated with metal concentrations. • Transcripts involved in the unfolded protein response (UPR) were induced. • Integration of transcriptomics and tissue levels provides insight to toxicity. - Abstract: Marine biomonitoring programs in the U.S. and Europe have historically relied on monitoring tissue concentrations of bivalves to monitor contaminant levels and ecosystem health. By integrating ‘omic methods with these tissue residue approaches we can uncover mechanistic insight to link tissue concentrations to potential toxic effects. In an effort to identify novel biomarkers and better understand the molecular toxicology of metal bioaccumulation in bivalves, we exposed the blue mussel, Mytilus edulis L., to sub-lethal concentrations (0.54 μM) of cadmium, lead, and a Cd + Pb mixture. Metal concentrations were measured in gill tissues at 1, 2, and 4 weeks, and increased linearly over the 4 week duration. In addition, there was evidence that Pb interfered with Cd uptake in the mixture treatment. Using a 3025 sequence microarray for M. edulis, we performed transcriptomic analysis, identifying 57 differentially expressed sequences. Hierarchical clustering of these sequences successfully distinguished the different treatment groups demonstrating that the expression profiles were reproducible among the treatments. Enrichment analysis of gene ontology terms identified several biological processes that were perturbed by the treatments, including nucleoside phosphate biosynthetic processes, mRNA metabolic processes, and response to stress. To identify transcripts whose expression level correlated with metal bioaccumulation, we performed Pearson correlation analysis. Several transcripts correlated with gill metal concentrations including mt10, mt20, and contig 48, an unknown transcript containing a wsc domain. In addition

  3. Proteomic analysis of Arabidopsis halleri shoots in response to the heavy metals cadmium and zinc and rhizosphere microorganisms.

    Science.gov (United States)

    Farinati, Silvia; DalCorso, Giovanni; Bona, Elisa; Corbella, Michela; Lampis, Silvia; Cecconi, Daniela; Polati, Rita; Berta, Graziella; Vallini, Giovanni; Furini, Antonella

    2009-11-01

    Arabidopsis halleri has the rare ability to colonize heavy metal-polluted sites and is an emerging model for research on adaptation and metal hyperaccumulation. The aim of this study was to analyze the effect of plant-microbe interaction on the accumulation of cadmium (Cd) and zinc (Zn) in shoots of an ecotype of A. halleri grown in heavy metal-contaminated soil and to compare the shoot proteome of plants grown solely in the presence of Cd and Zn or in the presence of these two metals and the autochthonous soil rhizosphere-derived microorganisms. The results of this analysis emphasized the role of plant-microbe interaction in shoot metal accumulation. Differences in protein expression pattern, identified by a proteomic approach involving 2-DE and MS, indicated a general upregulation of photosynthesis-related proteins in plants exposed to metals and to metals plus microorganisms, suggesting that metal accumulation in shoots is an energy-demanding process. The analysis also showed that proteins involved in plant defense mechanisms were downregulated indicating that heavy metals accumulation in leaves supplies a protection system and highlights a cross-talk between heavy metal signaling and defense signaling.

  4. On the linear response and scattering of an interacting molecule-metal system

    Energy Technology Data Exchange (ETDEWEB)

    Masiello, David J.; Schatz, George C.

    2010-01-01

    A many-body Green’s function approach to the microscopic theory of plasmon-enhanced spectroscopy is presented within the context of localized surface-plasmon resonancespectroscopy and applied to investigate the coupling between quantum-molecular and classical-plasmonic resonances in monolayer-coated silver nanoparticles. Electronic propagators or Green’s functions, accounting for the repeated polarizationinteraction between a single molecule and its image in a nearby nanoscale metal, are explicitly computed and used to construct the linear-response properties of the combined molecule-metal system to an external electromagnetic perturbation. Shifting and finite lifetime of states appear rigorously and automatically within our approach and reveal an intricate coupling between molecule and metal not fully described by previous theories. Self-consistent incorporation of this quantum-molecular response into the continuum-electromagnetic scattering of the molecule-metal target is exploited to compute the localized surface-plasmon resonance wavelength shift with respect to the bare metal from first principles.

  5. Analysis of the heavy metal-responsive transcription factor MTF-1 from human and mouse

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, H.P.; Brugnera, E.; Georgiev, O. [Universitaet Zuerich (Switzerland)] [and others

    1995-09-01

    Heavy metal-induced transcription in mammalian cells is conferred by the metalresponsive 70 kDa transcription factor MTF-1 which contains six zinc fingers and at least three activation domains. In previous cell transfection experiments we have shown that the zinc finger region confers an about 3 fold metal inducibility of transcription, due to its differential zinc binding. However, we also noted that human MTF-1 was more metal-responsive than the mouse factor (about 10 fold versus 3 fold, respectively). Here we analyze this difference in more detail by using chimeric human-mouse factors and narrow the critical region to a 64 amino acid stretch immediately downstream of the zinc fingers, overlapping with the acidic activation domain. A short human segment of this region (aa 313-377) confers efficient metal induction to the mouse MTF-1 when replacing the corresponding mouse region. However, high metal inducibility requires an unaltered MTF-I and is lost when human MTF-I is fused to the general activation domain of herpesvirus VP16 Wild type and truncation mutants of MTF-1 fused to VPI6 yield chimeras of high transcriptional activity, some exceeding the wildtype regulator, but only limited (about 3 fold) heavy metal inducibility. 22 refs., 4 figs.

  6. Differential responses of three sweetpotato metallothionein genes to abiotic stress and heavy metals.

    Science.gov (United States)

    Kim, Sun Ha; Jeong, Jae Cheol; Ahn, Young Ock; Lee, Haeng-Soon; Kwak, Sang-Soo

    2014-10-01

    Metallothioneins (MTs) are cysteine-rich, low molecular weight, metal-binding proteins that are widely distributed in living organisms. Plants produce metal-chelating proteins such as MTs to overcome the toxic effects of heavy metals. We cloned three MT genes from sweetpotato leaves [Ipomoea batatas (L.) Lam.]. The three IbMT genes were classified according to their cysteine residue alignment into type 1 (IbMT1), type 2 (IbMT2), and type 3 (IbMT3). IbMT1 was the most abundantly transcribed MT. It was predominantly expressed in leaves, roots, and callus. IbMT2 transcript was detected only in stems and fibrous roots, whereas IbMT3 was strongly expressed in leaves and stems. The IbMT expression profiles were investigated in plants exposed to heavy metals and abiotic stresses. The levels of IbMT1 expression were strongly elevated in response to Cd and Fe, and moderately higher in response to Cu. The IbMT3 expression pattern in response to heavy metals was similar to that of IbMT1. Exposure to abiotic stresses such as methyl viologen (MV; paraquat), NaCl, polyethylene glycol (PEG), and H2O2 up-regulated IbMT expression; IbMT1 responded strongly to MV and NaCl, whereas IbMT3 was induced by low temperature and PEG. Transgenic Escherichia coli overexpressing IbMT1 protein exhibited results suggest that IbMT could be a useful tool for engineering plants with enhanced tolerance to environmental stresses and heavy metals.

  7. Resonant Response in Mechanically Tunable Metasurface based on Crossed Metallic Gratings with Controllable Crossing Angle

    CERN Document Server

    Yachin, Vladimir V; Polevoy, Sergey Y; Tarapov, Sergey I

    2016-01-01

    We report on a resonant response in transmission spectra of a linearly polarized wave passing through the system of crossed gratings. Each grating consists of an array of parallel metallic strips located on the top of a dielectric substrate. It is revealed that the resonant position appears to be dependent on the angle of gratings crossing. It is found out that the resonant shift on the frequency scale appears as a result of increasing in the length of the resonating portion of the parallelogram periodic cell formed by the crossed metallic strips with decreasing crossing angle and the proposed design can be used in new types of planar metamaterials and filters.

  8. SIX SIGMA OPTIMIZATION IN SHEET METAL FORMING BASED ON DUAL RESPONSE SURFACE MODEL

    Institute of Scientific and Technical Information of China (English)

    LI Yuqiang; CUI Zhenshan; ZHANG Dongjuan; RUAN Xueyu; CHEN Jun

    2006-01-01

    Iterations in optimization and numerical simulation for the sheet metal forming process may lead to extensive computation. In addition, uncertainties in materials or processing parameters may have great influence on the design quality. A six sigma optimization method is proposed, by combining the dual response surface method (DRSM) and six sigma philosophy, to save computation cost and improve reliability and robustness of parts. Using this method, statistical technology,including the design of experiment and analysis of variance, approximate model and six sigma philosophy are integrated together to achieve improved quality. Two sheet metal forming processes are provided as examples to illustrate the proposed method.

  9. Synergy effects in the deformation response of thermodynamically open metal-hydrogen systems

    Energy Technology Data Exchange (ETDEWEB)

    Spivak, L V [Perm State University, Perm (Russian Federation)

    2008-09-30

    This paper reviews how polycrystalline and amorphous metals respond to the combined effect of a nonuniform force field and a high-intensity hydrogen (deuterium) diffusion flow. It is shown that deformation effects in such thermodynamically open systems result from phase transitions occurring due to changes in the hydrogen (deuterium) concentration. The necessary and sufficient criteria for observing such synergy effects are formulated. It is shown that the deformation response in a nonuniform stress field is a very sensitive means for indicating first and second-order structural phase transitions in metal-hydrogen systems. (reviews of topical problems)

  10. Thermodynamic and structural basis for electrochemical response of Cu–Zr based metallic glass

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chunzhi, E-mail: mse201109@126.com; Qiu, Nannan; Kong, Lingliang; Yang, Xiaodan; Li, Huiping

    2015-10-05

    Highlights: • Thermodynamic and structural basis for electrochemical response were proposed. • La improves the corrosion resistance by inhibition of the selective dissolution. • Corrosion of the MG responses well with thermodynamic and structural parameters. - Abstract: Cu–Zr based metallic glasses were prepared by hyperquenching strategy to explore the thermodynamic and structural basis for electrochemical response. The thermodynamic parameters and the local atomic structure were obtained. Corrosion resistance in seawater was investigated via potentiodynamic polarization curve. The results indicate that increasing thermodynamic parameter values improves the corrosion resistance. The topological instability represented by the nearest neighbor atomic distance yields same tendency as the corrosion resistance with La addition.

  11. Root carbon consumption and grain yield of spring wheat in response to phosphorus supply under two water regimes

    Institute of Scientific and Technical Information of China (English)

    GUAN Yu; QIAO Zhen; DU Jiu-yuan; DU Yan-lei

    2016-01-01

    In semiarid areas, cereal crops often alocate more biomass to root at the expense of aboveground yield. A pot experiment was conducted to investigate carbon consumption of roots and its impact on grain yield of spring wheat (Triticum aestivum L.) as affected by water and phosphorus (P) supply. A factorial design was used with six treatments namely two water regimes (at 80–75% and 50–45% ifeld capacity (FC)) and three P supply rates (P1=0, P2=44 and P3=109 µg P g–1 soil). At shooting and lfowering stages, root respiration and carbon consumption increased with the elevate of P supply rates, regardless of water conditions, which achieved the minimum and maximum at P1 under 50–45% FC and P3 under 80–75% FC, respectively. However, total aboveground biomass and grain yield were higher at P2 under 80–75% FC; and decreased with high P application (P3). The results indicated that rational or low P supply (80–75% of ifeld water capacity and 44 mg P kg–1 soil) should be recommended to improve grain yield by decreasing root carbon consumption in semiarid areas.

  12. Response Characteristics of Bisphenols on a Metal-Organic Framework-Based Tyrosinase Nanosensor.

    Science.gov (United States)

    Lu, Xianbo; Wang, Xue; Wu, Lidong; Wu, Lingxia; Dhanjai; Fu, Lei; Gao, Yuan; Chen, Jiping

    2016-06-29

    Bisphenols (BPs), which have more than ten kinds of structural analogues, are emerging as the most important endocrine disrupting chemicals that adversely affect human health and aquatic life. A tyrosinase nanosensor based on metal-organic frameworks (MOFs) and chitosan was developed to investigate the electrochemical response characteristics and mechanisms of nine kinds of BPs for the first time. The developed tyrosinase nanosensor showed a sensitive response to bisphenol A, bisphenol F, bisphenol E, bisphenol B, and bisphenol Z, and the responsive sensitivities were highly dependent on their respective log Kow values. However, the nanosensor showed no response to bisphenol S (BPS), bisphenol AP (BPAP), bisphenol AF (BPAF), or tetrabromobisphenol A, although BPS, BPAP, and BPAF have structures similar to those of the responsive BPs. The obtained results reveal that the electrochemical response of different BPs is affected not only by the molecular structure, especially the available ortho positions of phenolic hydroxyl groups, but also by the substituent group properties (electron acceptor or electron donor) on the bisphenol framework. The electronic cloud distribution of the phenolic hydroxyl groups, which is affected by the substituent group, determines whether the available ortho positions of phenolic hydroxyl groups can be oxidized by the tyrosinase biosensor. These response mechanisms are very significant as they can be used for predicting the response characteristics of many BPs and their various derivatives and metabolites on biosensors. The unexpected anti-interference ability of the biosensor to nine heavy metal ions was also discovered and discussed. The MOF-chitosan nanocomposite proves to be a promising sensing platform for the construction of diverse biosensors for selective detection of targets even in the presence of a high concentration of heavy metal ions.

  13. Differential response of marine organisms to certain metal and agrichemical pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Lee, H.H.; Xu, C.H.

    1984-10-01

    Oocyte maturation of the starfish, fertilization and embryogenesis of sea urchins, and the development of amphioxus and brine shrimps were used to assay the effects of several common metals and agrichemicals frequently found in marine environments. While brine shrimp embryos were tolerant to metals and agrichemicals used here, sea urchins and amphioxus showed a differential response to the common metal pollutants. Starfish oocyte maturation process was affected by agrichemicals. The results show that no one single organism, or its embryonic form, or a particular stage of development, can be used as the indicator for a particular pollutant. However, the use of lower forms of marine organisms can be useful collectively for environmental investigations and the management of waste disposal.

  14. Trace metal pyritization variability in response to mangrove soil aerobic and anaerobic oxidation processes.

    Science.gov (United States)

    Machado, W; Borrelli, N L; Ferreira, T O; Marques, A G B; Osterrieth, M; Guizan, C

    2014-02-15

    The degree of iron pyritization (DOP) and degree of trace metal pyritization (DTMP) were evaluated in mangrove soil profiles from an estuarine area located in Rio de Janeiro (SE Brazil). The soil pH was negatively correlated with redox potential (Eh) and positively correlated with DOP and DTMP of some elements (Mn, Cu and Pb), suggesting that pyrite oxidation generated acidity and can affect the importance of pyrite as a trace metal-binding phase, mainly in response to spatial variability in tidal flooding. Besides these aerobic oxidation effects, results from a sequential extraction analyses of reactive phases evidenced that Mn oxidized phase consumption in reaction with pyrite can be also important to determine the pyritization of trace elements. Cumulative effects of these aerobic and anaerobic oxidation processes were evidenced as factors affecting the capacity of mangrove soils to act as a sink for trace metals through pyritization processes.

  15. The design of supply chains

    DEFF Research Database (Denmark)

    Bøge Sørensen, Lars

    2004-01-01

    Keywords Supply Chain Management, Supply Chain Design, Literature studyAbstract Argues stability is a design objective for supply chain design alongside cost, leadtime and responsiveness. Performs an extensive literature study on supply chain design,identifies methods, theories and objectives...... in the existing literature. Describes the conceptexternal specificity and how it's used to design supply chains. Using the concept upstream,archetypes of risk minimal and maximal design are identified. Downstream the conceptdescribes two viable scenarios, one minimizing the impact, the other minimizing...... theprobability of (intended) departure of a supply chain partner. Finally, principles for supplychain design are described and managerial outlined....

  16. [Magnetic Response of Dust-loaded Leaves in Parks of Shanghai to Atmospheric Heavy Metal Pollution].

    Science.gov (United States)

    Liu, Fei; Chu, Hui-min; Zheng, Xiang-min

    2015-12-01

    To reveal the magnetic response to the atmospheric heavy metal pollution in leaves along urban parks, Camphor leaf samples, widely distributed at urban parks, were collected along the year leading wind direction of Shanghai, by setting two vertical and horizontal sections, using rock magnetic properties and heavy metal contents analysis. The results showed that the magnetic minerals of samples were predominated by ferromagnetic minerals, and both the concentration and grain size of magnetite particles gradually decreased with the winter monsoon direction from the main industrial district. A rigorous cleaning of leaves using ultrasonic agitator washer could remove about 63%-90% of low-field susceptibility values of the leaves, and this strongly indicated that the intensity of magnetic signal was mainly controlled by the PMs accumulated on the leaves surfaces. Moreover, there was a significant linear relationship between heavy metals contents (Fe, Mn, Zn, Cu, Cr, V and Pb) and magnetic parameters (0.442 ≤ R ≤ 0.799, P magnetic parameters of urban park leaves could be used as a proxy for atmospheric heavy metal pollution. The results of multivariate statistical analysis showed that the content of magnetic minerals and heavy metal indust-loaded tree leaves was affected by associated pollution of industry and traffic.

  17. Surface anchored metal-organic frameworks as stimulus responsive antifouling coatings.

    Science.gov (United States)

    Sancet, Maria Pilar Arpa; Hanke, Maximilian; Wang, Zhengbang; Bauer, Stella; Azucena, Carlos; Arslan, Hasan K; Heinle, Marita; Gliemann, Hartmut; Wöll, Christof; Rosenhahn, Axel

    2013-12-01

    Surface-anchored, crystalline and oriented metal organic frameworks (SURMOFs) have huge potential for biological applications due to their well-defined and highly-porous structure. In this work we describe a MOF-based, fully autonomous system, which combines sensing, a specific response, and the release of an antimicrobial agent. The Cu-containing SURMOF, Cu-SURMOF 2, is stable in artificial seawater and shows stimulus-responsive anti-fouling properties against marine bacteria. When Cobetia marina adheres on the SURMOF, the framework's response is lethal to the adhering microorganism. A thorough analysis reveals that this response is induced by agents secreted from the microbes after adhesion to the substrate, and includes a release of Cu ions resulting from a degradation of the SURMOF. The stimulus-responsive antifouling effect of Cu-SURMOF 2 demonstrates the first application of Cu-SURMOF 2 as autonomous system with great potential for further microbiological and cell culture applications.

  18. Zinc, iron, manganese and copper uptake requirement in response to nitrogen supply and the increased grain yield of summer maize.

    Science.gov (United States)

    Xue, Yanfang; Yue, Shanchao; Zhang, Wei; Liu, Dunyi; Cui, Zhenling; Chen, Xinping; Ye, Youliang; Zou, Chunqin

    2014-01-01

    The relationships between grain yields and whole-plant accumulation of micronutrients such as zinc (Zn), iron (Fe), manganese (Mn) and copper (Cu) in maize (Zea mays L.) were investigated by studying their reciprocal internal efficiencies (RIEs, g of micronutrient requirement in plant dry matter per Mg of grain). Field experiments were conducted from 2008 to 2011 in North China to evaluate RIEs and shoot micronutrient accumulation dynamics during different growth stages under different yield and nitrogen (N) levels. Fe, Mn and Cu RIEs (average 64.4, 18.1 and 5.3 g, respectively) were less affected by the yield and N levels. ZnRIE increased by 15% with an increased N supply but decreased from 36.3 to 18.0 g with increasing yield. The effect of cultivars on ZnRIE was similar to that of yield ranges. The substantial decrease in ZnRIE may be attributed to an increased Zn harvest index (from 41% to 60%) and decreased Zn concentrations in straw (a 56% decrease) and grain (decreased from 16.9 to 12.2 mg kg-1) rather than greater shoot Zn accumulation. Shoot Fe, Mn and Cu accumulation at maturity tended to increase but the proportions of pre-silking shoot Fe, Cu and Zn accumulation consistently decreased (from 95% to 59%, 90% to 71% and 91% to 66%, respectively). The decrease indicated the high reproductive-stage demands for Fe, Zn and Cu with the increasing yields. Optimized N supply achieved the highest yield and tended to increase grain concentrations of micronutrients compared to no or lower N supply. Excessive N supply did not result in any increases in yield or micronutrient nutrition for shoot or grain. These results indicate that optimized N management may be an economical method of improving micronutrient concentrations in maize grain with higher grain yield.

  19. Zinc, iron, manganese and copper uptake requirement in response to nitrogen supply and the increased grain yield of summer maize.

    Directory of Open Access Journals (Sweden)

    Yanfang Xue

    Full Text Available The relationships between grain yields and whole-plant accumulation of micronutrients such as zinc (Zn, iron (Fe, manganese (Mn and copper (Cu in maize (Zea mays L. were investigated by studying their reciprocal internal efficiencies (RIEs, g of micronutrient requirement in plant dry matter per Mg of grain. Field experiments were conducted from 2008 to 2011 in North China to evaluate RIEs and shoot micronutrient accumulation dynamics during different growth stages under different yield and nitrogen (N levels. Fe, Mn and Cu RIEs (average 64.4, 18.1 and 5.3 g, respectively were less affected by the yield and N levels. ZnRIE increased by 15% with an increased N supply but decreased from 36.3 to 18.0 g with increasing yield. The effect of cultivars on ZnRIE was similar to that of yield ranges. The substantial decrease in ZnRIE may be attributed to an increased Zn harvest index (from 41% to 60% and decreased Zn concentrations in straw (a 56% decrease and grain (decreased from 16.9 to 12.2 mg kg-1 rather than greater shoot Zn accumulation. Shoot Fe, Mn and Cu accumulation at maturity tended to increase but the proportions of pre-silking shoot Fe, Cu and Zn accumulation consistently decreased (from 95% to 59%, 90% to 71% and 91% to 66%, respectively. The decrease indicated the high reproductive-stage demands for Fe, Zn and Cu with the increasing yields. Optimized N supply achieved the highest yield and tended to increase grain concentrations of micronutrients compared to no or lower N supply. Excessive N supply did not result in any increases in yield or micronutrient nutrition for shoot or grain. These results indicate that optimized N management may be an economical method of improving micronutrient concentrations in maize grain with higher grain yield.

  20. Drivers of food waste and policy responses to the issue: The role of retailers in food supply chains

    OpenAIRE

    Adam, Alina

    2015-01-01

    One third of the entire food produced for our consumption is either lost or wasted at some point of the food supply chain. The problem of food waste does not only intensify the elementary problem of food insecurity in wasting precious nourishment - originally intended to be consumed - connected with its economic value, but the processing and disposal of food also wastes scarce resources such as water, agricultural land and energy, as well as increasing CO2 emissions. Recent studies identify c...

  1. 'Supply Push’ or ‘Demand Pull?’: Strategic Recommendations for the Responsible Development of Biofuel in China

    DEFF Research Database (Denmark)

    Ren, Jingzheng; Goodsite, Michael; Sovacool, Benjamin

    2015-01-01

    This study investigates China's biofuel industry—the third largest in the world—by combining a strength, weakness, opportunity and threats (SWOT) analysis with a method known as fuzzy analytic hierarchy process (FAHP). More specifically, the study employs SWOT analysis to identify the influential...... perform, adhering to a "supply push" mentality. Others focus on improving affordability and consumer awareness, adhering to a "demand pull" mentality....

  2. Nonlocal Response of Metallic Nanospheres Probed by Light, Electrons, and Atoms

    DEFF Research Database (Denmark)

    Christensen, Thomas; Yan, Wei; Raza, Søren

    2014-01-01

    Inspired by recent measurements on individual metallic nanospheres that cannot be explained with traditional classical electrodynamics, we theoretically investigate the effects of nonlocal response by metallic nanospheres in three distinct settings: atomic spontaneous emission, electron energy loss...... spectroscopy, and light scattering. These constitute two near-field and one far-field measurements, with zero-, one-, and two-dimensional excitation sources, respectively. We search for the clearest signatures of hydrodynamic pressure waves in nanospheres. We employ a linearized hydrodynamic model, and Mie......–Lorenz theory is applied for each case. Nonlocal response shows its mark in all three configurations, but for the two near-field measurements, we predict especially pronounced nonlocal effects that are not exhibited in far-field measurements. Associated with every multipole order is not only a single...

  3. Do code of conduct audits improve chemical safety in garment factories? Lessons on corporate social responsibility in the supply chain from Fair Wear Foundation.

    Science.gov (United States)

    Lindholm, Henrik; Egels-Zandén, Niklas; Rudén, Christina

    2016-10-01

    In managing chemical risks to the environment and human health in supply chains, voluntary corporate social responsibility (CSR) measures, such as auditing code of conduct compliance, play an important role. To examine how well suppliers' chemical health and safety performance complies with buyers' CSR policies and whether audited factories improve their performance. CSR audits (n = 288) of garment factories conducted by Fair Wear Foundation (FWF), an independent non-profit organization, were analyzed using descriptive statistics and statistical modeling. Forty-three per cent of factories did not comply with the FWF code of conduct, i.e. received remarks on chemical safety. Only among factories audited 10 or more times was there a significant increase in the number of factories receiving no remarks. Compliance with chemical safety requirements in garment supply chains is low and auditing is statistically correlated with improvements only at factories that have undergone numerous audits.

  4. 基于社会责任的可持续供应链网络设计%Design of Sustainable Supply Chain Network Based on Social Responsibility

    Institute of Scientific and Technical Information of China (English)

    许良; 滕燕强

    2015-01-01

    In this paper, we discussed the design of a closed-loop sustainable supply chain whose target was the minimization of the total cost and environmental impact and the maximization of its social responsibility, then on such basis, used the improved constraint process to get the valid solutions and verify the model, and at the end, obtained the optimal planning of the supply chain network.%讨论了多目标闭环可持续供应链网络设计问题,寻求总成本和环境影响最小化以及社会责任最大化的目标.基于此,利用改进的约束法求得有效解,验证模型的有效性,得出最优网络规划.

  5. The response of dark septate endophytes (DSE) to heavy metals in pure culture.

    Science.gov (United States)

    Ban, Yihui; Tang, Ming; Chen, Hui; Xu, Zhouying; Zhang, Haihan; Yang, Yurong

    2012-01-01

    Dark septate endophytes (DSE) occur widely in association with plants exposed to heavy metal stress. However, little is known about the response of DSE exposed to heavy metals. In this study, five DSE were isolated from the roots of Astragalus adsurgens Pall. seedlings growing on lead-zinc mine tailings in China. Based on morphological characteristics and DNA sequence analyses, the isolates were identified as Gaeumannomyces cylindrosporus, Paraphoma chrysanthemicola, Phialophora mustea, Exophiala salmonis, and Cladosporium cladosporioides. G. cylindrosporus was selected to explore responses to Pb stress. Scanning electron microscopic observations of G. cylindrosporus grown on solid medium revealed curling of hyphae and formation of hyphal coils in response to Pb. In contrast, in liquid medium, hyphae became thick and swollen with an increase in Pb (II) concentration. We interpret that these changes are related to the variation in cell wall components. We also demonstrated that fungal melanin content increased with the addition of Pb(II). Melanin, as an important component in the cell wall, is known to be an essential antioxidant responsible for decreasing heavy metal toxicity. We also measured the total soluble protein content and glutathione (GSH) concentrations in G. cylindrosporus and found that they initially increased and then decreased with the increase of Pb(II) concentrations. The antioxidant enzyme activities were also examined, and the results showed that superoxide dismutase (SOD) activity was significantly positively correlated with Pb(II) concentrations (r = 0.957, P<0.001). Collectively, our observations indicate that the intracellular antioxidant systems, especially fungal melanin, play an important role in abating the hazards of heavy metals.

  6. The response of dark septate endophytes (DSE to heavy metals in pure culture.

    Directory of Open Access Journals (Sweden)

    Yihui Ban

    Full Text Available Dark septate endophytes (DSE occur widely in association with plants exposed to heavy metal stress. However, little is known about the response of DSE exposed to heavy metals. In this study, five DSE were isolated from the roots of Astragalus adsurgens Pall. seedlings growing on lead-zinc mine tailings in China. Based on morphological characteristics and DNA sequence analyses, the isolates were identified as Gaeumannomyces cylindrosporus, Paraphoma chrysanthemicola, Phialophora mustea, Exophiala salmonis, and Cladosporium cladosporioides. G. cylindrosporus was selected to explore responses to Pb stress. Scanning electron microscopic observations of G. cylindrosporus grown on solid medium revealed curling of hyphae and formation of hyphal coils in response to Pb. In contrast, in liquid medium, hyphae became thick and swollen with an increase in Pb (II concentration. We interpret that these changes are related to the variation in cell wall components. We also demonstrated that fungal melanin content increased with the addition of Pb(II. Melanin, as an important component in the cell wall, is known to be an essential antioxidant responsible for decreasing heavy metal toxicity. We also measured the total soluble protein content and glutathione (GSH concentrations in G. cylindrosporus and found that they initially increased and then decreased with the increase of Pb(II concentrations. The antioxidant enzyme activities were also examined, and the results showed that superoxide dismutase (SOD activity was significantly positively correlated with Pb(II concentrations (r = 0.957, P<0.001. Collectively, our observations indicate that the intracellular antioxidant systems, especially fungal melanin, play an important role in abating the hazards of heavy metals.

  7. Bulk and surface electromagnetic response of metallic metamaterials to convection electrons

    OpenAIRE

    So, Jinkyu; Park, Gunsik; García-Vidal, Francisco J.; Jang, Kyu-Ha

    2011-01-01

    The following article appeared in Applied Physics Letters 99.7 (2011): 071106 and may be found at http://scitation.aip.org/content/aip/journal/apl/99/7/10.1063/1.3625952?ver=pdfcov The electromagnetic response of three-dimensional metallic metamaterials with isotropic effective index of refraction to fast-moving electrons is studied by numerical simulations. The considered metamaterials can support Cerenkov radiation [P. A. Cherenkov, Dokl. Akad. Nauk SSSR 2, 451 (1934)], and their effecti...

  8. Controlling optical responses through local dielectric resonance in nanometre metallic clusters

    Institute of Scientific and Technical Information of China (English)

    Chen Liang-Liang; Gu Ying; Wang Li-Jin; Gong Qi-Huang

    2007-01-01

    Optical responses in dilute composites are controlled through the local dielectric resonance of metallic clusters. We consider two located metallic clusters close to each other with admittances ε1 and ε2. Through varying the difference admittance ratio η[= (ε2 - ε0)/(ε1 - ε0)], we find that their optical responses are determined by the local resonance.There is a blueshift of absorption peaks with the increase of η. Simultaneously, it is known that the absorption peaks will be redshifted by enlarging the cluster size. By adjusting the nano-metallic cluster geometry, size and admittances,we can control the positions and intensities of absorption peaks effectively. We have also deduced the effective linear optical responses of three-comPonent composites εe = ε0 (1 + ∑nsn=1 [(γn1 + ηγn2 )/(ε0 (s - sn))]), and the sum rule of cross sections: ∑nsn=1 (γn1 + ηγn2) = Nh1 + Nh2, where Nh1and Nh2 are the numbers of ε1 and ε2 bonds along the electric field, respectively. These results may be beneficial to the study of surface plasmon resonances on a nanometre scale.

  9. Nonlocal response of metallic nanospheres probed by light, electrons, and atoms.

    Science.gov (United States)

    Christensen, Thomas; Yan, Wei; Raza, Søren; Jauho, Antti-Pekka; Mortensen, N Asger; Wubs, Martijn

    2014-02-25

    Inspired by recent measurements on individual metallic nanospheres that cannot be explained with traditional classical electrodynamics, we theoretically investigate the effects of nonlocal response by metallic nanospheres in three distinct settings: atomic spontaneous emission, electron energy loss spectroscopy, and light scattering. These constitute two near-field and one far-field measurements, with zero-, one-, and two-dimensional excitation sources, respectively. We search for the clearest signatures of hydrodynamic pressure waves in nanospheres. We employ a linearized hydrodynamic model, and Mie-Lorenz theory is applied for each case. Nonlocal response shows its mark in all three configurations, but for the two near-field measurements, we predict especially pronounced nonlocal effects that are not exhibited in far-field measurements. Associated with every multipole order is not only a single blueshifted surface plasmon but also an infinite series of bulk plasmons that have no counterpart in a local-response approximation. We show that these increasingly blueshifted multipole plasmons become spectrally more prominent at shorter probe-to-surface separations and for decreasing nanosphere radii. For selected metals, we predict hydrodynamic multipolar plasmons to be measurable on single nanospheres.

  10. Nursing Supplies

    Science.gov (United States)

    ... Stages Listen Español Text Size Email Print Share Nursing Supplies Page Content Article Body Throughout most of ... budget. (Nursing equipment also makes wonderful baby gifts.) Nursing Bras A well-made nursing bra that comfortably ...

  11. Growth and Chlorophyll Content of Canola Plants Supplied with Urea and Ammonium Nitrate in Response to Various Nickel Levels

    OpenAIRE

    BYBORDI, Ahmad; Mohammad Nabi GHEIBI

    2009-01-01

    Both the beneficial and the adverse effects of various nickel level supplements on growth and chlorophyll content of canola plants were evaluated while either urea or ammonium nitrate was supplied as the sole N source in the nutrient solutions. This study was arranged in completely randomized with three replications. Treatments included nutrient solution cultures containing urea and ammonium nitrate at the rate of 84 mg N L-1 separately as nitrogen sources with four nickel levels as NiSO4.6H2...

  12. Metabolic responses to metal pollution in shrimp Crangon affinis from the sites along the Laizhou Bay in the Bohai Sea.

    Science.gov (United States)

    Xu, Lanlan; Ji, Chenglong; Zhao, Jianmin; Wu, Huifeng

    2016-12-15

    Marine environment in the Laizhou Bay is potentially contaminated by metals from industrial discharges. In this study, metal concentrations in shrimps Crangon affinis indicated that two typical sites (S6283 and S5283) close to Longkou and Zhaoyuan cities along the Laizhou Bay have been contaminated by metals, including Cd, As, Cu, Ni, Co, and Mn. In particular, Cd and As were the main metal contaminants in S6283. In S5283, however, Cu was the most important metal contaminant. The metabolic responses in the shrimps indicated that the metal pollution in S6283 and S5283 induced disturbances in osmotic regulation and energy metabolism and reduced anaerobiosis, lipid metabolism, and muscle movement. However, alteration in the levels of dimethylglycine, dimethylamine, arginine, betaine, and glutamine indicated that the metal pollution in S5283 induced osmotic stress through different pathways compared to that in S6283. In addition, dimethylamine might be the biomarker of Cu in shrimp C. affinis.

  13. Time-domain Response of a Metal Detector to a Target Buried in Soil with Frequency-dependent Magnetic Susceptibility

    Science.gov (United States)

    2016-07-06

    performance of induction metal detectors widely used in humanitarian demining. This paper studies the specific case of the time-domain response of a small...known to adversely affect the performance of metal detectors . The included analysis and computations extend previous work which has been done mostly in...target in soil based on the presented results. However, computational results complemented with experimental data extend the understanding of the effect that soil has on metal detectors .

  14. Cobalt bioavailability from hard metal particles. Further evidence that cobalt alone is not responsible for the toxicity of hard metal particles

    Energy Technology Data Exchange (ETDEWEB)

    Lison, D. (Industrial Toxicology and Occupational Medicine Unit, Catholic Univ. of Louvain, Brussels (Belgium)); Lauwerys, R. (Industrial Toxicology and Occupational Medicine Unit, Catholic Univ. of Louvain, Brussels (Belgium))

    1994-08-01

    Hard metal is an alloy of tungsten carbide (WC) in a matrix of cobalt metal (Co). The inhalation of hard metal dust can cause an alveolitis which may progress to interstitial fibrosis. This study was undertaken to compare, both in vivo and in vitro, the bioavailability of cobalt metal when mixed or not with WC and to assess whether this factor had any influence on the cellular toxicity of hard metal particles. In vivo, non-toxic doses of cobalt metal were administered intratracheally in the rat, alone (Co, 0.03 mg/100 g) or mixed with tungsten carbide (WC-Co, 0.5 mg/100 g containing 6.3% of cobalt metal particles). Sequential measurements of cobalt in the lung and in urine demonstrated that the retention time of the metal in the lung was longer in Co- than in WC-Co-treated animals. In vitro, the cellular cobalt uptake was higher when the metal was presented to the macrophages as WC-Co. However, there was no relationship between the cellular uptake of cobalt and the occurrence of toxicity, since the intracellular concentration of cobalt associated with the occurrence of a cytotoxic effect of WC-Co particles was insufficient to exert the same effect when resulting from exposure to Co alone. This clearly indicates that increased bioavailability of cobalt is not the mechanism by which hard metal particles exhibit their cellular toxicity. These observations confirm and extend our previous findings supporting the view that cobalt is not the only component responsible for the toxicity of hard metal particles which should be considered as a specific toxic entity. (orig.)

  15. Ab initio phonon coupling and optical response of hot electrons in plasmonic metals

    Science.gov (United States)

    Brown, Ana M.; Sundararaman, Ravishankar; Narang, Prineha; Goddard, William A.; Atwater, Harry A.

    2016-08-01

    Ultrafast laser measurements probe the nonequilibrium dynamics of excited electrons in metals with increasing temporal resolution. Electronic structure calculations can provide a detailed microscopic understanding of hot electron dynamics, but a parameter-free description of pump-probe measurements has not yet been possible, despite intensive research, because of the phenomenological treatment of electron-phonon interactions. We present ab initio predictions of the electron-temperature dependent heat capacities and electron-phonon coupling coefficients of plasmonic metals. We find substantial differences from free-electron and semiempirical estimates, especially in noble metals above transient electron temperatures of 2000 K, because of the previously neglected strong dependence of electron-phonon matrix elements on electron energy. We also present first-principles calculations of the electron-temperature dependent dielectric response of hot electrons in plasmonic metals, including direct interband and phonon-assisted intraband transitions, facilitating complete theoretical predictions of the time-resolved optical probe signatures in ultrafast laser experiments.

  16. Metal-organic semiconductor interfacial barrier height determination from internal photoemission signal in spectral response measurements

    Science.gov (United States)

    Kumar, Sandeep; Iyer, S. Sundar Kumar

    2017-04-01

    Accurate and convenient evaluation methods of the interfacial barrier ϕb for charge carriers in metal semiconductor (MS) junctions are important for designing and building better opto-electronic devices. This becomes more critical for organic semiconductor devices where a plethora of molecules are in use and standardised models applicable to myriads of material combinations for the different devices may have limited applicability. In this paper, internal photoemission (IPE) from spectral response (SR) in the ultra-violet to near infra-red range of different MS junctions of metal-organic semiconductor-metal (MSM) test structures is used to determine more realistic MS ϕb values. The representative organic semiconductor considered is [6, 6]-phenyl C61 butyric acid methyl ester, and the metals considered are Al and Au. The IPE signals in the SR measurement of the MSM device are identified and separated before it is analysed to estimate ϕb for the MS junction. The analysis of IPE signals under different bias conditions allows the evaluation of ϕb for both the front and back junctions, as well as for symmetric MSM devices.

  17. Behavior of native species Arrhenatherum elatius (Poaceae) and Sonchus transcaspicus (Asteraceae) exposed to a heavy metal-polluted field: plant metal concentration, phytotoxicity, and detoxification responses.

    Science.gov (United States)

    Lu, Yan; Li, Xinrong; He, Mingzhu; Zeng, Fanjiang

    2013-01-01

    The application of vegetation cover for the phytomanagement of heavy metal-polluted soils needs prior investigation on the suitability of plant species. In this study, behaviors of Arrhenatherum elatius and Sonchus transcaspicus, two native perennial grasses that currently grow in a mine tailing, were investigated through plant metal concentration, phytotoxicity and their detoxification responses. Both of the species accumulated Ni, Cu, Cd, Co, Mn, Pb, Cr, and Zn in shoots far below criterion concentration as a hyperaccumulators; thus, neither of them were found to be hyperaccumulators. A. elatius accumulated metals in roots and then in shoots, on the contrary, in S. transcaspicus metals were preferentially accumulated in shoots. Plants exposure to such metals resulted in oxidative stress in the considered organs as indicated by the changes in chlorophyll fluorescence, chlorophyll contents, malondialdehyde (MDA) levels and antioxidative enzyme activities. A. elatius seemed to be more affected by metal-induced oxidative stress than S. transcaspicus. Correspondingly, S. transcaspicus showed a greater capacity to adapt to metal-induced oxidative stress, depending on more effective antioxidative defense mechanisms to protect itself from oxidative damage. These findings allowed us to conclude that both of these plant species could be suitable for the phytostabilization of metal-polluted soils.

  18. Corn (Hybrid BC666 Response to Supply Nutrients from Organic Nutrition (Azotobacter and Manure in Climate Conditions of Lorestan

    Directory of Open Access Journals (Sweden)

    M Beiranvadi

    2013-10-01

    Full Text Available Maize (Zea mays L. is one of the most important crops that used for food, feeding and industrial products and in Iran a developing cultivation. In order to study of corn s reactions (Hybrid BC666 to supply nutrients to organic nutrition (Bacteria and manure as summer sown in climate conditions of Lorestan. An experiment was conduct in Meteorology Station of Lorestan s agriculture research field during 2007 four planting densities as 75000,85000, 95000 and 105000 plant ha-1 in main plots and two amount manure (24 and 30 ton ha-1 set in subplot and application and non application Azotobacter chroococcum set in sub-sub plots , were arranged in a split split plot design as base of RCBD. The results indicated that plant densities significally affected Biological yield,grain yield and ear number in m2. Increase plant densities of 75000 to 105000 plant in per hectare caused 42% addition biological yield,65% addition grain yield and 42% raise ear number in m2 .eventually researches showed in climate conditions of Lorestan corn to be able as summer sown to enter rotation cycle. thus corn summer sown planting densities 105000 plant ha-1 is optimum density and application 24 ton ha-1 manure for supply plant nutrients to be enough. In rich soils with fertilizers, not available field for to show beneficial effects bacteria.

  19. La cadena de suministro del sector metalúrgico: un análisis de sus principales eslabones (The Supply Chain in the metallurgical sector: an analysis of the main links

    Directory of Open Access Journals (Sweden)

    Patricia Carbajo-de-Lera

    2011-12-01

    Full Text Available Los directivos actuales conciben que la competencia ya no es empresa frente a empresa, sino que desborda este plano generándose una competencia cadena de suministro frente a cadena de suministro. Por ello, la gestión de la cadena de suministro se convierte en un elemento clave para la supervivencia empresarial y la obtención de ventajas competitivas. El diseño de la cadena de suministro viene definido, en buena parte, por las características del sector al que pertenece. En consecuencia, es de interés realizar análisis sectoriales. El presente trabajo tiene como objetivo analizar la cadena de suministro en un sector de gran importancia en la economía española, como es el metalúrgico. En concreto, buscamos determinar su cadena de suministro, definiendo los principales eslabones que la configuran y las relaciones entre ellos.Abstract: In the current business context, competition is no longer firm against firm, but has moved on to a higher plane, with the generation of supply chain against supply chain competition.  Therefore, Supply Chain Management (SCM has strategic relevance as a source of competitive advantage. The design of the supply chain is defined largely by the characteristics of the sector. Consequently, sectorial analysis is required. The aim of this paper is to analyze the supply chain of the metallurgical sector. Specifically, it will be focused on determining its supply chain and defining its main links and relationships.

  20. Supply chain planning classification

    Science.gov (United States)

    Hvolby, Hans-Henrik; Trienekens, Jacques; Bonde, Hans

    2001-10-01

    Industry experience a need to shift in focus from internal production planning towards planning in the supply network. In this respect customer oriented thinking becomes almost a common good amongst companies in the supply network. An increase in the use of information technology is needed to enable companies to better tune their production planning with customers and suppliers. Information technology opportunities and supply chain planning systems facilitate companies to monitor and control their supplier network. In spite if these developments, most links in today's supply chains make individual plans, because the real demand information is not available throughout the chain. The current systems and processes of the supply chains are not designed to meet the requirements now placed upon them. For long term relationships with suppliers and customers, an integrated decision-making process is needed in order to obtain a satisfactory result for all parties. Especially when customized production and short lead-time is in focus. An effective value chain makes inventory available and visible among the value chain members, minimizes response time and optimizes total inventory value held throughout the chain. In this paper a supply chain planning classification grid is presented based current manufacturing classifications and supply chain planning initiatives.

  1. Effect of heavy metals on growth response and antioxidant defense protection in Bacillus cereus.

    Science.gov (United States)

    Behera, Madhumita; Dandapat, Jagneshwar; Rath, Chandi Charan

    2014-11-01

    Bacterial cells in aerobic environment generate reactive oxygen species which may lead to oxidative stress, induced by a wide range of environmental factors including heavy metals. In the present context an attempt has been made to determine the toxic impact of cadmium and copper on growth performance, oxidative stress, and relative level of antioxidant protection in Bacillus cereus. Outcome of this study suggests that both the metal ions depleted the growth rate in this organism with respect to time and concentration of the metal ions. CdCl2 exposure induced extracellular glutathione (GSH) production, whereas, its level was declined in response to CuSO4. Superoxide dismutase (SOD) activity and hydrogen peroxide (H2 O2 ) content was elevated under CdCl2 stress but the activity of catalase (CAT) was inhibited. In contrast, incubation of bacteria with CuSO4 exhibited decreased SOD activity with concomitant rise in CAT activity and H2 O2 content. We also observed elevation of intracellular GSH level in this bacteria following supplementation of N-acetyl cysteine (NAC) in the medium. Overall findings of this study indicated differential toxicity of CdCl2 and CuSO4 in inducing oxidative stress, depleting growth rate and the possible involvement of GSH and CAT in adaptive antioxidant response.

  2. 基于Nerlove模型的山东省玉米供给反应研究%Supply Response for Maize in Shandong Province Based on Nerlove Model

    Institute of Scientific and Technical Information of China (English)

    范少玲; 史建民

    2013-01-01

    根据1978~ 2010年山东省玉米价格和播种面积的年度数据,运用Nerlove模型,对山东省玉米供给反应进行实证分析.结果表明,山东省玉米供给价格弹性较低,即山东省玉米播种面积不能根据玉米价格的变动做出迅速调整,当价格发生突涨或突跌时,玉米的供给不能迅速适应这种变化,进而加剧玉米供求不平衡.为此,一方面要加快玉米价格信息公开平台建设,另一方面在坚持严格保护耕地的前提下加大包括玉米在内的粮食作物的补贴政策力度,并保持政策的连续性.%According to annual data of maize price and sowing area during 1978 -2010 and adopting Nerlove model, the supply response of maize in Shandong Province was analyzed. The results showed that, price elasticity of maize supply in Shandong Province is low, that is to say, Shandong Province can't adjust maize sowing area rapidly to the price changes of maize. When the price of maize rises or drops suddenly , the supply of maize can' t adapt the changes quickly, then aggravate the imbalance of supply and demand. Therefore, on the one hand, we should speed up the construction of public platform price information; on the other hand, in the premise of insisting protecting farmland strictly , increase subsidies policy of grain crop including maize, and maintain the continuity of policies.

  3. Separation of metabolic supply and demand: aerobic glycolysis as a normal physiological response to fluctuating energetic demands in the membrane.

    Science.gov (United States)

    Epstein, Tamir; Xu, Liping; Gillies, Robert J; Gatenby, Robert A

    2014-01-01

    Cancer cells, and a variety of normal cells, exhibit aerobic glycolysis, high rates of glucose fermentation in the presence of normal oxygen concentrations, also known as the Warburg effect. This metabolism is considered abnormal because it violates the standard model of cellular energy production that assumes glucose metabolism is predominantly governed by oxygen concentrations and, therefore, fermentative glycolysis is an emergency back-up for periods of hypoxia. Though several hypotheses have been proposed for the origin of aerobic glycolysis, its biological basis in cancer and normal cells is still not well understood. We examined changes in glucose metabolism following perturbations in membrane activity in different normal and tumor cell lines and found that inhibition or activation of pumps on the cell membrane led to reduction or increase in glycolysis, respectively, while oxidative phosphorylation remained unchanged. Computational simulations demonstrated that these findings are consistent with a new model of normal physiological cellular metabolism in which efficient mitochondrial oxidative phosphorylation supplies chronic energy demand primarily for macromolecule synthesis and glycolysis is necessary to supply rapid energy demands primarily to support membrane pumps. A specific model prediction was that the spatial distribution of ATP-producing enzymes in the glycolytic pathway must be primarily localized adjacent to the cell membrane, while mitochondria should be predominantly peri-nuclear. The predictions were confirmed experimentally. Our results show that glycolytic metabolism serves a critical physiological function under normoxic conditions by responding to rapid energetic demand, mainly from membrane transport activities, even in the presence of oxygen. This supports a new model for glucose metabolism in which glycolysis and oxidative phosphorylation supply different types of energy demand. Cells use efficient but slow-responding aerobic metabolism

  4. Spirulina-Templated Metal Microcoils with Controlled Helical Structures for THz Electromagnetic Responses

    Science.gov (United States)

    Kamata, Kaori; Piao, Zhenzi; Suzuki, Soichiro; Fujimori, Takahiro; Tajiri, Wataru; Nagai, Keiji; Iyoda, Tomokazu; Yamada, Atsushi; Hayakawa, Toshiaki; Ishiwara, Mitsuteru; Horaguchi, Satoshi; Belay, Amha; Tanaka, Takuo; Takano, Keisuke; Hangyo, Masanori

    2014-05-01

    Microstructures in nature are ultrafine and ordered in biological roles, which have attracted material scientists. Spirulina forms three-dimensional helical microstructure, one of remarkable features in nature beyond our current processing technology such as lithography in terms of mass-productivity and structural multiplicity. Spirulina varies its diameter, helical pitch, and/or length against growing environment. This unique helix is suggestive of a tiny electromagnetic coil, if composed of electro-conductive metal, which brought us main concept of this work. Here, we describe the biotemplating process onto Spirulina surface to fabricate metal microcoils. Structural parameters of the microcoil can be controlled by the cultivation conditions of Spirulina template and also purely one-handed microcoil can be fabricated. A microcoil dispersion sheet exhibited optically active response attributed to structural resonance in terahertz-wave region.

  5. Early human bone response to laser metal sintering surface topography: a histologic report.

    Science.gov (United States)

    Mangano, Carlo; Piattelli, Adriano; d'Avila, Susana; Iezzi, Giovanna; Mangano, Francesco; Onuma, Tatiana; Shibli, Jamil Awad

    2010-01-01

    This histologic report evaluated the early human bone response to a direct laser metal sintering implant surface retrieved after a short period of healing. A selective laser sintering procedure using a Ti-6Al-4V alloy powder with a particle size of 25-45 microm prepared this surface topography. One experimental microimplant was inserted into the anterior mandible of a patient during conventional implant surgery of the jaw. The microimplant and surrounding tissues were removed after 2 months of unloaded healing and were prepared for histomorphometric analysis. Histologically, the peri-implant bone appeared in close contact with the implant surface, whereas marrow spaces could be detected in other areas along with prominently stained cement lines. The mean of bone-to-implant contact was 69.51%. The results of this histologic report suggest that the laser metal sintering surface could be a promising alternative to conventional implant surface topographies.

  6. Polarization field gradient effects in inhomogeneous metal-ferroelectric bilayers: Optical response and band gap tunability

    Science.gov (United States)

    Vivas C., H.; Vargas-Hernández, C.

    2012-06-01

    Optical constants, reflectivity response and direct band gap energy (Egd) were calculated and simulated by developing an electrodynamic-based model for a three medium system, namely vacuum/ferroelectric film/metallic substrate. Depolarization effects due to the contact between the metallic substrate and the FE film, as well as the spatially dependent profile of the dielectric susceptibility ε(z) enter into the formalism by adapting the phenomenological Landau-Ginzburg-Devonshire theory (LGD). Absorption coefficient is obtained from the Lambert-Beer-Bouguer (LBB) approximation and the direct band gap energy as a function of the characteristic length is calculated by using the general Tauc power law. Numerical simulations lead to range of values for tunable Egd from 2.6 to 2.8 eV for characteristic lengths up to 30% the thickness of the film, in concordance with recent reports.

  7. Third-order terahertz response of gapped, nearly-metallic armchair graphene nanoribbons

    Science.gov (United States)

    Wang, Yichao; Andersen, David R.

    2016-11-01

    We use time dependent perturbation theory to study the terahertz nonlinear response of gapped intrinsic and extrinsic nearly-metallic armchair graphene nanoribbons of finite length under an applied electric field. Generally, the nonlinear conductances exhibit contributions due to single-photon, two-photon, and three-photon processes. The interference between each of these processes results in remarkably complex behavior for the third-order conductances, including quantum dot signatures that should be measurable with a relatively simple experimental configuration. Notably, we observe sharp resonances in the isotropic third-order response due to the Van Hove singularities in the density of states at one-, two-, and three-photon resonances. However, these resonances are absent in the anisotropic third-order response; a result of the overall symmetry of the system.

  8. Growth and Chlorophyll Content of Canola Plants Supplied with Urea and Ammonium Nitrate in Response to Various Nickel Levels

    Directory of Open Access Journals (Sweden)

    Ahmad BYBORDI

    2009-12-01

    Full Text Available Both the beneficial and the adverse effects of various nickel level supplements on growth and chlorophyll content of canola plants were evaluated while either urea or ammonium nitrate was supplied as the sole N source in the nutrient solutions. This study was arranged in completely randomized with three replications. Treatments included nutrient solution cultures containing urea and ammonium nitrate at the rate of 84 mg N L-1 separately as nitrogen sources with four nickel levels as NiSO4.6H2O at the rates of 0, 0.01, 0.05 and 0.1 mg Ni L-1. Plants were allowed to grow for 6 weeks then leaves chlorophyll content and shoots and roots fresh and dry weight were determined. Both plant growth and leaves chlorophyll content of the urea-fed plants increased significantly with the increase in nickel content up to 0.1 mg Ni L-1. However, root fresh and dry weight increased up to 0.01 mg Ni L-1 and started to decrease with further increase in solutions nickel content. Nickel did not affect these parameters with plants supplied with ammonium nitrate significantly. In these plants, the optimum nickel level for shoot growth and leaves chlorophyll content was 0.05 mg L-1 and for root fresh and dry weight was 0.01 mg Ni L-1. Further increase in Ni concentration reduced growth. As a whole, plants received urea plus nickel performed better than those received ammonium nitrate plus nickel.

  9. Characterization of leaf apoplastic peroxidases and metabolites in Vigna unguiculata in response to toxic manganese supply and silicon.

    Science.gov (United States)

    Führs, Hendrik; Götze, Stefanie; Specht, André; Erban, Alexander; Gallien, Sébastien; Heintz, Dimitri; Van Dorsselaer, Alain; Kopka, Joachim; Braun, Hans-Peter; Horst, Walter J

    2009-01-01

    Previous work suggested that the apoplastic phenol composition and its interaction with apoplastic class III peroxidases (PODs) are decisive in the development or avoidance of manganese (Mn) toxicity in cowpea (Vigna unguiculata L.). This study characterizes apoplastic PODs with particular emphasis on the activities of specific isoenzymes and their modulation by phenols in the Mn-sensitive cowpea cultivar TVu 91 as affected by Mn and silicon (Si) supply. Si reduced Mn-induced toxicity symptoms without affecting the Mn uptake. Blue Native-PAGE combined with Nano-LC-MS/MS allowed identification of a range of POD isoenzymes in the apoplastic washing fluid (AWF). In Si-treated plants Mn-mediated induction of POD activity was delayed. Four POD isoenzymes eluted from the BN gels catalysed both H(2)O(2)-consuming and H(2)O(2)-producing activity with pH optima at 6.5 and 5.5, respectively. Four phenols enhanced NADH-peroxidase activity of these isoenzymes in the presence of Mn(2+) (p-coumaric=vanillic>benzoic>ferulic acid). p-Coumaric acid-enhanced NADH-peroxidase activity was inhibited by ferulic acid (50%) and five other phenols (50-90%). An independent component analysis (ICA) of the total and apoplastic GC-MS-based metabolome profile showed that Mn, Si supply, and the AWF fraction (AWF(H(2)O), AWF(NaCl)) significantly changed the metabolite composition. Extracting non-polar metabolites from the AWF allowed the identification of phenols. Predominantly NADH-peroxidase activity-inhibiting ferulic acid appeared to be down-regulated in Mn-sensitive (+Mn, -Si) and up-regulated in Mn-tolerant (+Si) leaf tissue. The results presented here support the previously hypothesized role of apoplastic NADH-peroxidase and its activity-modulating phenols in Mn toxicity and Si-enhanced Mn tolerance.

  10. Propensity to metal accumulation and oxidative stress responses of two benthic species (Cerastoderma edule and Nephtys hombergii): are tolerance processes limiting their responsiveness?

    Science.gov (United States)

    Marques, Ana; Piló, David; Araújo, Olinda; Pereira, Fábio; Guilherme, Sofia; Carvalho, Susana; Santos, Maria Ana; Pacheco, Mário; Pereira, Patrícia

    2016-05-01

    The chronic exposure of benthic organisms to metals in sediments can lead to the development of tolerance mechanisms, thus diminishing their responsiveness. This study aims to evaluate the accumulation profiles of V, Cr, Co, Ni, As, Cd, Pb and Hg and antioxidant system responses of two benthic organisms (Cerastoderma edule, Bivalvia; Nephtys hombergii, Polychaeta). This approach will provide clarifications about the ability of each species to signalise metal contamination. Organisms of both species were collected at the Tagus estuary, in two sites with distinct contamination degrees (ALC, slightly contaminated; BAR, highly contaminated). Accordingly, C. edule accumulated higher concentrations of As, Pb and Hg at BAR compared to ALC. However, antioxidant responses of C. edule were almost unaltered at BAR and no peroxidative damage occurred, suggesting adjustment mechanisms to the presence of metals. In contrast, N. hombergii showed a minor propensity to metal accumulation, only signalising spatial differences for As and Pb and accumulating lower concentrations of metals than C. edule. The differences in metal accumulation observed between species might be due to their distinctive foraging behaviour and/or the ability of N. hombergii to minimise the metal uptake. Despite that, the accumulation of As and Pb was on the basis of the polychaete antioxidant defences inhibition at BAR, including CAT, SOD, GR and GPx. The integrated biomarker response index (IBRv2) confirmed that N. hombergii was more affected by metal exposure than C. edule. In the light of current findings, in field-based studies, the information of C. edule as a bioindicator should be complemented by that provided by another benthic species, since tolerance mechanisms to metals can hinder a correct diagnosis of sediment contamination and of the system's health. Overall, the present study contributed to improve the lack of fundamental knowledge of two widespread and common estuarine species, providing

  11. Propensity to metal accumulation and oxidative stress responses of two benthic species (Cerastoderma edule and Nephtys hombergii): are tolerance processes limiting their responsiveness?

    KAUST Repository

    Marques, Ana

    2016-02-24

    The chronic exposure of benthic organisms to metals in sediments can lead to the development of tolerance mechanisms, thus diminishing their responsiveness. This study aims to evaluate the accumulation profiles of V, Cr, Co, Ni, As, Cd, Pb and Hg and antioxidant system responses of two benthic organisms (Cerastoderma edule, Bivalvia; Nephtys hombergii, Polychaeta). This approach will provide clarifications about the ability of each species to signalise metal contamination. Organisms of both species were collected at the Tagus estuary, in two sites with distinct contamination degrees (ALC, slightly contaminated; BAR, highly contaminated). Accordingly, C. edule accumulated higher concentrations of As, Pb and Hg at BAR compared to ALC. However, antioxidant responses of C. edule were almost unaltered at BAR and no peroxidative damage occurred, suggesting adjustment mechanisms to the presence of metals. In contrast, N. hombergii showed a minor propensity to metal accumulation, only signalising spatial differences for As and Pb and accumulating lower concentrations of metals than C. edule. The differences in metal accumulation observed between species might be due to their distinctive foraging behaviour and/or the ability of N. hombergii to minimise the metal uptake. Despite that, the accumulation of As and Pb was on the basis of the polychaete antioxidant defences inhibition at BAR, including CAT, SOD, GR and GPx. The integrated biomarker response index (IBRv2) confirmed that N. hombergii was more affected by metal exposure than C. edule. In the light of current findings, in field-based studies, the information of C. edule as a bioindicator should be complemented by that provided by another benthic species, since tolerance mechanisms to metals can hinder a correct diagnosis of sediment contamination and of the system’s health. Overall, the present study contributed to improve the lack of fundamental knowledge of two widespread and common estuarine species, providing

  12. 基于供应链的企业社会责任研究综述%Reviews of the Research on the Corporate Social Responsibility Based on the Supply Chain

    Institute of Scientific and Technical Information of China (English)

    郭睿华

    2015-01-01

    Research on the corporate social responsibility based on the supply chain has received increasing attention, study abroad is relatively mature. From several aspects, we went over the current studies on the social responsibility of supply chain enterprises, and explored the direction for future research in this ifeld. That is supply chain management of corporate social responsibility, the research of social responsibility risk, supply chain network research and social responsibility of supply chain for the food business . We hope that this paper can expand and innovate the research for both supply chain and corporate social responsibility.%供应链上企业社会责任研究日益受到重视,且国外研究相对成熟,本文通过对国内外研究现状的分析,对于国内研究,主要从供应链上企业社会责任管理、社会责任风险、供应链网络研究和针对食品企业的供应链企业社会责任几方面进行了分析,探索了今后研究的方向,希望通过本文能够对二者的研究思路和方向有所拓展与创新.

  13. Transcriptional response of stress genes to metal exposure in zebra mussel larvae and adults

    Energy Technology Data Exchange (ETDEWEB)

    Navarro, Anna; Faria, Melissa; Barata, Carlos [Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18, 08034 Barcelona (Spain); Pina, Benjamin, E-mail: bpcbmc@cid.csic.e [Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18, 08034 Barcelona (Spain)

    2011-01-15

    Development of stress markers for the invader freshwater zebra mussel (Dreissena polymorpha) is of great interest for both conservation and biomonitoring purposes. Gene expression profiles of several putative or already established gene expression stress markers (Metallothionein, Superoxide dismutase, Catalase, Glutathione S transferase, Glutathione peroxidase, Cytochrome c oxidase, the multixenobiotic resistance P-gp1, and heat shock proteins HSP70 and HSP90) were analyzed by quantitative Real-Time PCR in adults and pediveliger larvae after exposure to metals (Hg, Cu, Cd). A defined pattern of coordinated responses to metal exposure and, presumably, to oxidative stress was observed in gills and digestive gland from adults. A similar, albeit partial response was observed in larvae, indicating an early development of stress-related gene responses in zebra mussel. The tools developed in this study may be useful both for future control strategies and for the use of zebra mussel as sentinel species in water courses with stable populations. - Coordinated expression of stress genes in zebra mussel.

  14. Plant response to heavy metals and organic pollutants in cell culture and at whole plant level

    Energy Technology Data Exchange (ETDEWEB)

    Golan-Goldhirsh, A.; Barazani, O. [Ben-Gurion Univ. of The Negev, The Jacob Blaustein Inst. for Desert Research, Albert Katz Dept. of Dryland Biotechnologies, Desert Plant Biotechnology Lab., Sede Boqer Campus (Israel); Nepovim, A.; Soudek, P.; Vanek, T. [Inst. of Organic Chemistry and Biochemistry (Czech Republic); Smrcek, S.; Dufkova, L.; Krenkova, S. [Faculty of Natural Sciences, Charles Univ. (Czech Republic); Yrjala, K. [Univ. of Helsinki, Dept. of Biosciences, Div. of General Microbiology, Helsinki (Finland); Schroeder, P. [Inst. for Soil Ecology, GSF National Research Center for Environment and Health, Neuherberg, Oberschleissheim (Germany)

    2004-07-01

    Background. Increasing awareness in the last decade concerning environmental quality had prompted research into 'green solutions' for soil and water remediation, progressing from laboratory in vitro experiments to pot and field trials. In vitro cell culture experiments provide a convenient system to study basic biological processes, by which biochemical pathways, enzymatic activity and metabolites can be specifically studied. However, it is difficult to relate cell cultures, calli or even hydroponic experiments to the whole plant response to pollutant stress. In the field, plants are exposed to additional a-biotic and biotic factors, which complicate further plant response. Hence, we often see that in vitro selected species perform poorly under soil and field conditions. Soil physical and chemical properties, plant-mycorrhizal association and soil-microbial activity affect the process of contaminant degradation by plants and/or microorganisms, pointing to the importance of pot and field experiments. Objective. This paper is a joint effort of a group of scientists in COST action 837. It represents experimental work and an overview on plant response to environmental stress from in vitro tissue culture to whole plant experiments in soil. Results. Results obtained from in vitro plant tissue cultures and whole plant hydroponic experiments indicate the phytoremediation potential of different plant species and the biochemical mechanisms involved in plant tolerance. In pot experiments, several selected desert plant species, which accumulated heavy metal in hydroponic systems, succeeded in accumulating the heavy metal in soil conditions as well. Conclusions and recommendations. In vitro plant tissue cultures provide a useful experimental system for the study of the mechanisms involved in the detoxification of organic and heavy metal pollutants. However, whole plant experimental systems, as well as hydroponics followed by pot and field trials, are essential when

  15. A porphyrin-based metal-organic framework as a pH-responsive drug carrier

    Science.gov (United States)

    Lin, Wenxin; Hu, Quan; Jiang, Ke; Yang, Yanyu; Yang, Yu; Cui, Yuanjing; Qian, Guodong

    2016-05-01

    A low cytotoxic porphyrin-based metal-organic framework (MOF) PCN-221, which exhibited high PC12 cell viability via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium (MTT) assay, was selected as an oral drug carrier. Methotrexate (MTX) was chosen as the model drug molecule which was absorbed into inner pores and channels of MOFs by diffusion. PCN-221 showed high drug loading and sustained release behavior under physiological environment without "burst effect". The controlled pH-responsive release of drugs by PCN-221 revealed its promising application in oral drug delivery.

  16. Bulk and surface electromagnetic response of metallic metamaterials to convection electrons

    Science.gov (United States)

    So, Jin-Kyu; Jang, Kyu-Ha; Park, Gun-Sik; Garcia-Vidal, F. J.

    2011-08-01

    The electromagnetic response of three-dimensional metallic metamaterials with isotropic effective index of refraction to fast-moving electrons is studied by numerical simulations. The considered metamaterials can support Cerenkov radiation [P. A. Cherenkov, Dokl. Akad. Nauk SSSR 2, 451 (1934)], and their effective dielectric behavior is confirmed by the detailed angular dependence of the generated radiation cone on the kinetic energy of electrons. Moreover, in addition to the predicted bulk modes, surface electromagnetic excitation is observed in a specific type of metamaterials and its dispersion is sensitive to the thickness of the subwavelength rods.

  17. Trajectories of Microbial Community Function in Response to Accelerated Remediation of Subsurface Metal Contaminants

    Energy Technology Data Exchange (ETDEWEB)

    Firestone, Mary [Regents of the Univ. of Callifornia, Oakland, CA (United States)

    2015-01-14

    Objectives of proposed research were to; Determine if the trajectories of microbial community composition and function following organic carbon amendment can be related to, and predicted by, key environmental determinants; Assess the relative importance of the characteristics of the indigenous microbial community, sediment, groundwater, and concentration of organic carbon amendment as the major determinants of microbial community functional response and bioremediation capacity; and Provide a fundamental understanding of the microbial community ecology underlying subsurface metal remediation requisite to successful application of accelerated remediation and long-term stewardship of DOE-IFC sites.

  18. Defending the leaf surface: intra- and inter-specific differences in silicon deposition in grasses in response to damage and silicon supply

    Directory of Open Access Journals (Sweden)

    Sue Elaine Hartley

    2015-02-01

    Full Text Available Understanding interactions between grasses and their herbivores is central to the conservation of species-rich grasslands and the protection of our most important crops against pests. Grasses employ a range of defenses against their natural enemies; silicon-based defenses have been shown to be one of the most effective. Silicon (Si is laid down on the leaf surface as spines and other sharp bodies, known as phytoliths, making grasses abrasive and their foliage indigestible to herbivores. Previous studies on Si defenses found that closely related species may have similar levels of Si in the leaves but differ markedly in abrasiveness. Here we show how the number, shape and distribution of Si-rich phytoliths and spines differ within and between different grass species and demonstrate that species also differ in their ability to change the deposition and distribution of these defenses in response to damage or increases in Si supply. Specifically, we tested the response of two genotypes of Festuca arundinacea known to differ in their surface texture and 3 different grass species (F. ovina, F. rubra and Deschampsia cespitosa differing in their abrasiveness to combined manipulation of leaf damage and Si supply. F.arundinacea plants with a harsh leaf surface had higher Si content and more spines on their leaf surface than soft varieties. F. ovina and D. cespitosa plants increased their leaf Si concentration and produced an increase in the number of leaf spines and phytoliths on the leaf surface in response to Si addition. F rubra also increased leaf Si content in response to treatments, particularly in damaged leaves, but did not deposit this in the form of spines or increased densities of phytoliths. We discuss how the form in which grasses deposit Si may affect their anti-herbivore characteristics and consider the ecological and agricultural implications of the differences in allocation to Si-based defenses between grass species.

  19. Defending the leaf surface: intra- and inter-specific differences in silicon deposition in grasses in response to damage and silicon supply.

    Science.gov (United States)

    Hartley, Sue E; Fitt, Rob N; McLarnon, Emma L; Wade, Ruth N

    2015-01-01

    Understanding interactions between grasses and their herbivores is central to the conservation of species-rich grasslands and the protection of our most important crops against pests. Grasses employ a range of defenses against their natural enemies; silicon-based defenses have been shown to be one of the most effective. Silicon (Si) is laid down on the leaf surface as spines and other sharp bodies, known as phytoliths, making grasses abrasive and their foliage indigestible to herbivores. Previous studies on Si defenses found that closely related species may have similar levels of Si in the leaves but differ markedly in abrasiveness. Here we show how the number, shape and distribution of Si-rich phytoliths and spines differ within and between different grass species and demonstrate that species also differ in their ability to change the deposition and distribution of these defenses in response to damage or increases in Si supply. Specifically, we tested the response of two genotypes of Festuca arundinacea known to differ in their surface texture and three different grass species (F. ovina, F. rubra, and Deschampsia cespitosa) differing in their abrasiveness to combined manipulation of leaf damage and Si supply. F. arundinacea plants with a harsh leaf surface had higher Si content and more spines on their leaf surface than soft varieties. F. ovina and D. cespitosa plants increased their leaf Si concentration and produced an increase in the number of leaf spines and phytoliths on the leaf surface in response to Si addition. F rubra also increased leaf Si content in response to treatments, particularly in damaged leaves, but did not deposit this in the form of spines or increased densities of phytoliths. We discuss how the form in which grasses deposit Si may affect their anti-herbivore characteristics and consider the ecological and agricultural implications of the differences in allocation to Si-based defenses between grass species.

  20. Optical response of metallic and insulating VO{sub 2} calculated with the LDA approach

    Energy Technology Data Exchange (ETDEWEB)

    Mossanek, R J O; Abbate, M [Departamento de Fisica, Universidade Federal do Parana, Caixa Postal 19081, 81531-990 Curitiba PR (Brazil)

    2007-08-29

    We calculated the optical response of metallic and insulating VO{sub 2} using the local density approximation (LDA) approach. The band structure calculation was based on the full-potential linear-muffin-tin method. The imaginary part of the dielectric function {epsilon}{sub 2}({omega}) is related to the different optical transitions. The Drude tail in the calculation of the metallic phase corresponds to intraband d-d transitions. The calculation in the insulating phase is characterized by the transitions to the d{sub parallel}* band. The low-frequency features, 0.0-5.0 eV, correspond to V 3d-V 3d transitions, whereas the high-frequency structures, 5.0-12 eV, are related to O 2p-V 3d transitions. The calculation helps to explain the imaginary part of the dielectric function {epsilon}{sub 2}({omega}), as well as the electron-energy-loss and reflectance spectra. The results reproduce not only the energy position and relative intensity of the features in the spectra, but also the main changes across the metal-insulator transition and the polarization dependence. The main difference is a shift of about 0.6 eV in the calculation of the insulating phase. This discrepancy arises because the LDA calculation underestimates the value of the band gap.

  1. Novel Power Supply Equipment Used for High-Pressure Metal Halide Discharge Lamp%一种高气压金属卤化物气体放电灯用新型电源的原理研究

    Institute of Scientific and Technical Information of China (English)

    王汝文; 姚晓莉; 姚建军

    2001-01-01

    提出一种用于高气压金属卤化物气体放电灯供电电源的新型主电路拓扑.不需设置专门提供起燃脉冲的高压脉冲发生器,只须改变电路工作频率,即能满足这类灯在起燃、负阻运行、稳态运行各阶段对电源不同输出特性的要求.电路结构简单,装置体积小.在负载稳定运行后,电源输出特性近似电流源,开关器件电流幅值较低,并可实现零电流换相.讨论了这种电源的工作原理和系统结构,并给出了模拟负载的PSPICE仿真和实验室试验结果,表明其完全符合电路的工作原理和设计思想.%A new circuit topology of power supply for high-pressure metal halide discharge lamp is proposed. Without a high voltage pulse generator for firing the lamp, the supply can apply voltage in three different modes for the lamp operation from firing to steady state through modulation of the switch operation frequency. The supply circuit scheme is simplified and its volume can be also reduced. The switches in propsed supply can operate in lower current amplitude, nearly current source and ZCS mode. The principle of the supply and its scheme were described. Some simulation and experiment results for modeling load were given as well.

  2. Evidence of phloem boron transport in response to interrupted boron supply in white lupin (Lupinus albus L. cv. Kiev Mutant) at the reproductive stage.

    Science.gov (United States)

    Huang, Longbin; Bell, Richard W; Dell, Bernard

    2008-01-01

    The present study investigates whether previously acquired boron (B) in mature leaves in white lupin can be retranslocated into the rapidly growing young reproductive organs, in response to short-term (3 d) interrupted B supply. In a preliminary experiment with white lupin in soil culture, B concentrations in phloem exudates remained at 300-500 microM, which were substantially higher than those in the xylem sap (10-30 microM). The high ratios of B concentrations in phloem exudates to those in the xylem sap were close to values published for potassium in lupin plants. To differentiate 'old' B in the shoot from 'new' B in the root, an experiment was carried out in which the plants were first supplied with 20 microM (11)B (99.34% by weight) in nutrient solution for 48 d after germination (DAG) until early flowering and then transferred into either 0.2 microM or 20 microM (10)B (99.47% by weight) for 3 d. Regardless of the (10)B treatments, significant levels of (11)B were found in the phloem exudates (200-300 microM in 20 microM (10)B and 430 microM in 0.2 microM (10)B treatment) and xylem sap over the three days even without (11)B supply to the root. In response to the 0.2 microM (10)B treatment, the translocation of previously acquired (11)B in the young (the uppermost three leaves), matured, and old leaves was enhanced, coinciding with the rise of (11)B in the xylem sap (to >15 microM) and phloem exudates (430 microM). The evidence supports the hypothesis that previously acquired B in the shoot was recirculated to the root via the phloem, transferred into the xylem in the root, and transported in the xylem to the shoot. In addition, some previously acquired (11)B in the leaves may have been translocated into the rapidly growing inflorescence. Phloem B transport resulted in the continued net increment of (11)B in the flowers over 3 d without (11)B supply. However, it is still uncertain whether the amount of B available for recirculation is adequate to support

  3. Byproduct metals and rare-earth elements used in the production of light-emitting diodes—Overview of principal sources of supply and material requirements for selected markets

    Science.gov (United States)

    Wilburn, David R.

    2012-01-01

    The use of light-emitting diodes (LEDs) is expanding because of environmental issues and the efficiency and cost savings achieved compared with use of traditional incandescent lighting. The longer life and reduced power consumption of some LEDs have led to annual energy savings, reduced maintenance costs, and lower emissions of carbon dioxide, sulfur dioxide, and nitrogen oxides from powerplants because of the resulting decrease in energy consumption required for lighting applications when LEDs are used to replace less-energy-efficient sources. Metals such as arsenic, gallium, indium, and the rare-earth elements (REEs) cerium, europium, gadolinium, lanthanum, terbium, and yttrium are important mineral materials used in LED semiconductor technology. Most of the world's supply of these materials is produced as byproducts from the production of aluminum, copper, lead, and zinc. Most of the rare earths required for LED production in 2011 came from China, and most LED production facilities were located in Asia. The LED manufacturing process is complex and is undergoing much change with the growth of the industry and the changes in demand patterns of associated commodities. In many respects, the continued growth of the LED industry, particularly in the general lighting sector, is tied to its ability to increase LED efficiency and color uniformity while decreasing the costs of producing, purchasing, and operating LEDs. Research is supported by governments of China, the European Union, Japan, the Republic of Korea, and the United States. Because of the volume of ongoing research in this sector, it is likely that the material requirements of future LEDs may be quite different than LEDs currently (2011) in use as industry attempts to cut costs by reducing material requirements of expensive heavy rare-earth phosphors and increasing the sizes of wafers for economies of scale. Improved LED performance will allow customers to reduce the number of LEDs in automotive, electronic

  4. Information in the supply chain: measuring supply chain performance

    OpenAIRE

    Bytheway, Andrew

    1995-01-01

    Information is one of many factors in the development of supply chain operations. It is a key factor in a number of new initiatives, such as: business process management. partnership development, efficient customer response, tighter integration of supply chain operations and outsourcing of ancillary operations. Improvement of the supply chain takes place at different levels: simple efficiency (the Improvement of existing processes), improved quality of service (the redesign of ...

  5. Ph responsive capsules containing composite coatings for corrosion inhibition in metal alloys

    Science.gov (United States)

    Kashi, Kiran Bhat

    Hexavalent chromes have been used as effective corrosion inhibitors due to their high inhibitor efficiency and low cost for the protection of several metal alloys. However, owing to their toxicity federal legislations restrict the use and distribution of these highly toxic materials. The need for an environmentally friendly yet effective alternative to the chrome based corrosion inhibitors has led to the investigation of rare earth metals as potential candidates. Cerium is one such rare earth metal that has received considerable attention as an alternative to hexavalent chromes. However, the high water solubility of some of the cerium salts makes it difficult for the incorporation of such salts in coatings. In this work, pH responsive microcapsules containing cerium salts were synthesized using an internally phase separated emulsion polymerization technique. Core shell microcapsule consisting of a water core containing dissolved cerium salts were synthesized. The synthesized capsules were characterized using characterization techniques such as Fourier Transform Infrared (FTIR) spectroscopy, UV-vis spectroscopy, Dynamic Mechanical Analysis (DMA), Thermo-Gravimetric Analysis (TGA), and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). The structure and morphology of the capsules were studied using electron microscopy techniques. The synthesized capsules were dispersed in 2K epoxy coatings and applied on aluminum alloy 2024 T-3 and cold rolled steel substrates. These coatings were exposed to salt spray (ASTM B117) and electrochemically evaluated using electrochemical impedance spectroscopy (EIS), potentio-dynamic(PD) polarization, cyclic voltammetry(CV), open circuit potential(OCP) measurements. Localized corrosion assessment was also performed on the coated metal alloys using Scanning electrochemical microscopy (SECM) to understand the mechanism of corrosion inhibition using cerium encapsulated microcapsules.

  6. Ac-conductivity and dielectric response of new zinc-phosphate glass/metal composites

    Energy Technology Data Exchange (ETDEWEB)

    Maaroufi, A., E-mail: maaroufi@fsr.ac.ma [University of Mohammed V, Laboratory of Composite Materials, Polymers and Environment, Department of Chemistry, Faculty of Sciences, P.B. 1014, Rabat-Agdal (Morocco); Oabi, O. [University of Mohammed V, Laboratory of Composite Materials, Polymers and Environment, Department of Chemistry, Faculty of Sciences, P.B. 1014, Rabat-Agdal (Morocco); Lucas, B. [XLIM UMR 7252 – Université de Limoges/CNRS, 123 avenue Albert Thomas, 87060 Limoges Cedex (France)

    2016-07-01

    The ac-conductivity and dielectric response of new composites based on zinc-phosphate glass with composition 45 mol%ZnO–55 mol%P{sub 2}O{sub 5}, filled with metallic powder of nickel (ZP/Ni) were investigated by impedance spectroscopy in the frequency range from 100 Hz to 1 MHz at room temperature. A high percolating jump of seven times has been observed in the conductivity behavior from low volume fraction of filler to the higher fractions, indicating an insulator – semiconductor phase transition. The measured conductivity at higher filler volume fraction is about 10{sup −1} S/cm and is frequency independent, while, the obtained conductivity for low filler volume fraction is around 10{sup −8} S/cm and is frequency dependent. Moreover, the elaborated composites are characterized by high dielectric constants in the range of 10{sup 5} for conductive composites at low frequencies (100 Hz). In addition, the distribution of the relaxation processes was also evaluated. The Debye, Cole-Cole, Davidson–Cole and Havriliak–Negami models in electric modulus formalism were used to model the observed relaxation phenomena in ZP/Ni composites. The observed relaxation phenomena are fairly simulated by Davidson–Cole model, and an account of the interpretation of results is given. - Highlights: • Composites of ZnO-P{sub 2}O{sub 5}/metal were investigated by impedance spectroscopy. • Original ac-conductivity behavior was discovered in ZnO-P{sub 2}O{sub 5}/metal composites. • High dielectric constant is measured in ZnO-P{sub 2}O{sub 5}/metal composites. • Dielectric constant as filler function is well interpreted with percolation theory. • Observed relaxation processes are well described using electric modulus formalism.

  7. The development dynamics of the maize root transcriptome responsive to heavy metal Pb pollution.

    Science.gov (United States)

    Gao, Jian; Zhang, Yongzhong; Lu, Chaolong; Peng, Hua; Luo, Mao; Li, Gaoke; Shen, Yaou; Ding, Haiping; Zhang, Zhiming; Pan, Guangtang; Lin, Haijian

    2015-03-01

    Lead (Pb), as a heavy metal element, has become the most important metal pollutant of the environment. With allocating a relatively higher proportion of its biomass in roots, maize could be a potential important model to study the phytoremediation of Pb-contaminated soil. Here we analyzed the maize root transcriptome of inbred lines 9782 under heavy metal lead (Pb) pollution, which was identified as a non-hyperaccumulator for Pb in roots. In the present study, more than 98 millions reads were mapped to define gene structure and detect polymorphism, thereby to qualify transcript abundance along roots development under Pb treatment. A total of 17,707, 17,440, 16,998 and 16,586 genes were identified in maize roots at four developmental stages (0, 12 h, 24 h and 48 h) respectively and 2,825, 2,626, 2161 and 2260 stage-specifically expressed genes were also identified respectively. In addition, based on our RNA-Seq data, transcriptomic changes during maize root development responsive to Pb were investigated. A total of 384 differentially expressed genes (DEGs) (log2Ratio ≥ 1, FDR ≤ 0.001) were identified, of which, 36 genes with significant alteration in expression were detected in four developmental stages; 12 DEGs were randomly selected and successful validated by qRT-PCR. Additionally, many transcription factor families might act as the important regulators at different developmental stages, such as bZIP, ERF and GARP et al. These results will expand our understanding of the complex molecular and cellular events in maize root development and provide a foundation for future study on root development in maize under heavy metal pollution and other cereal crops.

  8. Chromatic Mechanical Response in 2-D Layered Transition Metal Dichalcogenide (TMDs) based Nanocomposites

    Science.gov (United States)

    Rahneshin, Vahid; Khosravi, Farhad; Ziolkowska, Dominika A.; Jasinski, Jacek B.; Panchapakesan, Balaji

    2016-10-01

    The ability to convert photons of different wavelengths directly into mechanical motion is of significant interest in many energy conversion and reconfigurable technologies. Here, using few layer 2H-MoS2 nanosheets, layer by layer process of nanocomposite fabrication, and strain engineering, we demonstrate a reversible and chromatic mechanical response in MoS2-nanocomposites between 405 nm to 808 nm with large stress release. The chromatic mechanical response originates from the d orbitals and is related to the strength of the direct exciton resonance A and B of the few layer 2H-MoS2 affecting optical absorption and subsequent mechanical response of the nanocomposite. Applying uniaxial tensile strains to the semiconducting few-layer 2H-MoS2 crystals in the nanocomposite resulted in spatially varying energy levels inside the nanocomposite that enhanced the broadband optical absorption up to 2.3 eV and subsequent mechanical response. The unique photomechanical response in 2H-MoS2 based nanocomposites is a result of the rich d electron physics not available to nanocomposites based on sp bonded graphene and carbon nanotubes, as well as nanocomposite based on metallic nanoparticles. The reversible strain dependent optical absorption suggest applications in broad range of energy conversion technologies that is not achievable using conventional thin film semiconductors.

  9. Enhanced electromechanical response of Ionic Polymer-Metal Composite (IPMC) actuators by various Nafion roughening levels

    Science.gov (United States)

    Wang, Yanjie; Liu, Jiayu; Chen, Hualing

    2016-04-01

    Recently, Ionic polymer metal composites (IPMCs), becoming an increasingly popular material, are used as soft actuators for its inherent properties of light weight, flexibility, softness, especial efficient transformation from electrical energy to mechanical energy with large bending strain response to low activation voltage. This paper mainly focuses on the suitable conditions for surface-roughening of Nafion 117 membrane. The surfaces of Nafion membrane were pretreated and optimized by sandblasting, mainly considering the change of sandblasting time and powder size. The modified surfaces are characterized in terms of their topography from the confocal laser scanning microscope (CLSM) and SEM. Then, the detailed change in surface and interfacial electrodes and performances for IPMC actuators prepared by the roughened membranes, were measured and discussed. The results show that an optimized roughening condition with large interface area (capacitance) can effectively increases the electromechanical responses of IPMC.

  10. Application backwards characteristics analysis method to dynamic response of metals under high pressure

    Directory of Open Access Journals (Sweden)

    Pan Hao

    2015-01-01

    Full Text Available Dynamic yield strength of metals/alloys depends on loading pressure and rates sensitively. With the development of laser interferometer measurement system, extracting strength information from window/free surface velocity profiles in shock and ramp loading experiments is becoming an important method to investigate materials’ dynamic response under high pressure and high strain rates. Backwards characteristics analysis method (BCAM can analyze the velocity profiles more reasonable because it accounts for bending of the incoming characteristics due to impedance mismatch between the sample and window. Synthetic analyses of reverse impact experiment and graded-density impactor loading-releasing experiment suggest that BCAM can give more accurate results including sound speed-particle velocity and yield strength at high pressure than incremental impedance matching method. We use BCAM to analyze velocity profiles of Sn in shock-release experiments and obtain its shear modulus and yield strength at different shock pressure and investigate its phase transition and dynamic unloading response.

  11. Nonlinear response of metallic acGNR to an elliptically-polarized terahertz excitation field

    CERN Document Server

    Wang, Yichao

    2016-01-01

    We present a theoretical description of the nonlinear response induced by an elliptically-polarized terahertz beam normally-incident on intrinsic and extrinsic metallic armchair graphene nanorib- bons. Our results show that using a straightforward experimental setup, it should be possible to observe novel polarization-dependent nonlinearities at low excitation field strengths of the or- der of 10 4 V/m. At low temperatures the Kerr nonlinearities in extrinsic nanoribbons persist to significantly higher excitation frequencies than they do for linear polarizations, and at room tem- peratures, the third-harmonic nonlinearities are enhanced by 2-3 orders of magnitude. Finally, the Fermi-level and temperature dependence of the nonlinear response is characterized.

  12. Impact Response of Cantilever Fiber Metal Laminate (FML Plates Using a Coupled Analytical-Numerical Method

    Directory of Open Access Journals (Sweden)

    Faramarz Ashenai Ghasemi

    2013-05-01

    Full Text Available In this study, dynamic response of cantilever Fiber Metal Laminate (FML plates subjected to the impact of a large mass is studied. Aluminum (Al sheets are placed instead of some Fiber Reinforced Plastic (FRP layers. The effect of the Al layers on contact force and deflection of the plates is investigated by considering the interaction between the impactor and the target in the impact analysis. A two degrees-of-freedom system consisting of springs-masses and finite element modeling of the ABAQUS/Explicit software were employed to model the interaction between the impactor and the target. The results indicate that some parameters like the layer sequence, mass and velocity of the impactor, mass of the target are important factors which affect the impact response of the plates.

  13. Optimization of metal working fluids treatment using calcium chloride by response surface methodology

    Directory of Open Access Journals (Sweden)

    HA. Jamali

    2016-11-01

    Full Text Available Background: Extensive use of metal working fluids degrades their chemical composition. They should be treated using a safe method. Chemical coagulation-flocculation process is one the treatment methods. Objective: The aim of this study was to optimize the coagulation-flocculation process using calcium chloride in metal working fluids treatment. Methods: This laboratory based study was performed in School of Health affiliated to Qazvin University of Medical Sciences in 2014. Using calcium chloride and a six-compartment jar, the efficiency of coagulation-flocculation process was assessed for removal of chemical oxygen demand (COD and turbidity and amount of released oil. Central composite design (CCD and response surface methodology (RSM were applied to optimize the treatment operation parameters (pH and dosage of coagulant. Quadratic models were developed for calculation of the three responses (COD, turbidity, and released oil. Findings: The optimum condition for coagulation-flocculation process was seen after treatment with 4.2 g/L calcium chloride at pH 3.71 in which COD and turbidity removal efficiency were 93% and 96.9%, respectively and the amount of released oil was 31.8 ml. The level of desirability was 91.2%. The values of laboratory study were in good agreement with the values predicted by the model. Conclusion: Metal working fluids treatment with calcium chloride was efficient in the removal of pollution parameters. Dosage of calcium chloride was similar to the conventional coagulants such as Alum, but its efficiency was higher.

  14. Structurally Well-Defined Sigmoidal Gold Clusters: Probing the Correlation between Metal Atom Arrangement and Chiroptical Response.

    Science.gov (United States)

    He, Xin; Wang, Yuechao; Jiang, Hong; Zhao, Liang

    2016-05-04

    Asymmetric arrangement of metal atoms is crucial for understanding the chirality origin of chiral metal nanoclusters and facilitating the design and development of new chiral catalysts and chiroptical devices. Here, we describe the construction of four asymmetric gold and gold-silver clusters by chirality transfer from diimido ligands. The acquired metal clusters show strong circular dichroism (CD) response with large anisotropy factors of up to 6 × 10(-3), larger than the values of most reported chiral gold nanoclusters. Regardless of the same absolute configuration of the applied three diimido ligands, sigmoidal and reverse-sigmoidal arrangements of gold atoms both can be achieved, which resultantly produce an opposite Cotton effect within a specific absorption range. On the basis of the detailed structural characterization via X-ray crystallography and contrast experiments, the chirality contribution of the imido ligand, the asymmetrically arranged metal cluster, and the chiral arrangement of aromatic rings of phosphine ligands have been qualitatively evaluated. Time-dependent DFT calculations reveal that the chiroptical property of the acquired metal clusters is mainly influenced by the asymmetrically arranged metal atoms. Correlation of asymmetric arrangements of metal atoms in clusters with their chiroptical response provides a viable means of fabricating a designable chiral surface of metal nanoclusters and opens a broader prospect for chiral cluster application.

  15. Responsive nanoporous metals: recoverable modulations on strength and shape by watering

    Science.gov (United States)

    Ye, Xing-Long; Liu, Ling-Zhi; Jin, Hai-Jun

    2016-08-01

    Many biological materials can readily modulate their mechanical properties and shape by interacting with water in the surrounding environment, which is essential to their high performance in application. In contrast, typical inorganic materials (such as the metals) cannot change their strength and shape without involving thermal/mechanical treatments. By introducing nano-scale porous structure and exploiting a simple physical concept—the water-capillarity in nanopores, here we report that a ‘dead’ metal can be transformed into a ‘smart’ material with water-responsive properties. We demonstrate that the apparent strength, volume and shape of nanoporous Au and Au(Pt) can be modulated in situ, dramatically and recoverably, in response to water-dipping and partial-drying. The amplitude of strength-modulation reaches 20 MPa, which is nearly 50% of the yield strength at initial state. This approach also leads to reversible length change up to 1.3% in nanoporous Au and a large reversible bending motion of a bi-layer strip with tip displacement of ∼20 mm, which may be used for actuation. This method is simple and effective, occurring in situ under ambient conditions and requiring no external power, analogous to biological materials. The findings may open up novel applications in many areas such as micro-robotics and bio-medical devices.

  16. Transcriptomic Analysis of Cadmium Stress Response in the Heavy Metal Hyperaccumulator Sedum alfredii Hance

    Science.gov (United States)

    Yang, Xiaoe; Liu, Jian-Xiang

    2013-01-01

    The Sedum alfredii Hance hyperaccumulating ecotype (HE) has the ability to hyperaccumulate cadmium (Cd), as well as zinc (Zn) and lead (Pb) in above-ground tissues. Although many physiological studies have been conducted with these plants, the molecular mechanisms underlying their hyper-tolerance to heavy metals are largely unknown. Here we report on the generation of 9.4 gigabases of adaptor-trimmed raw sequences and the assembly of 57,162 transcript contigs in S. alfredii Hance (HE) shoots by the combination of Roche 454 and Illumina/Solexa deep sequencing technologies. We also have functionally annotated the transcriptome and analyzed the transcriptome changes upon Cd hyperaccumulation in S. alfredii Hance (HE) shoots. There are 110 contigs and 123 contigs that were up-regulated (Fold Change ≧2.0) and down-regulated (Fold Change ≦0.5) by chronic Cd treatment in S. alfredii Hance (HE) at q-value cutoff of 0.005, respectively. Quantitative RT-PCR was employed to compare gene expression patterns between S. alfredii Hance (HE) and non-hyperaccumulating ecotype (NHE). Our results demonstrated that several genes involved in cell wall modification, metal translocation and remobilization were more induced or constitutively expressed at higher levels in HE shoots than that in NHE shoots in response to Cd exposure. Together, our study provides large-scale expressed sequence information and genome-wide transcriptome profiling of Cd responses in S. alfredii Hance (HE) shoots. PMID:23755133

  17. Transcriptomic analysis of cadmium stress response in the heavy metal hyperaccumulator Sedum alfredii Hance.

    Directory of Open Access Journals (Sweden)

    Jun Gao

    Full Text Available The Sedum alfredii Hance hyperaccumulating ecotype (HE has the ability to hyperaccumulate cadmium (Cd, as well as zinc (Zn and lead (Pb in above-ground tissues. Although many physiological studies have been conducted with these plants, the molecular mechanisms underlying their hyper-tolerance to heavy metals are largely unknown. Here we report on the generation of 9.4 gigabases of adaptor-trimmed raw sequences and the assembly of 57,162 transcript contigs in S. alfredii Hance (HE shoots by the combination of Roche 454 and Illumina/Solexa deep sequencing technologies. We also have functionally annotated the transcriptome and analyzed the transcriptome changes upon Cd hyperaccumulation in S. alfredii Hance (HE shoots. There are 110 contigs and 123 contigs that were up-regulated (Fold Change ≥ 2.0 and down-regulated (Fold Change metal translocation and remobilization were more induced or constitutively expressed at higher levels in HE shoots than that in NHE shoots in response to Cd exposure. Together, our study provides large-scale expressed sequence information and genome-wide transcriptome profiling of Cd responses in S. alfredii Hance (HE shoots.

  18. Influence of methionine supply on the response of lactational performance of dairy cows to supplementary folic acid and vitamin B12.

    Science.gov (United States)

    Preynat, A; Lapierre, H; Thivierge, M C; Palin, M F; Matte, J J; Desrochers, A; Girard, C L

    2009-04-01

    supplement of folic acid and vitamin B(12) on lactational performance of dairy cows were not due to an improvement in methyl groups supply, because RPM supplement, a source of preformed methyl groups, did not alter the cow responsiveness to vitamin supplements.

  19. Heavy metal mediated innate immune responses of the Indian green frog, Euphlyctis hexadactylus (Anura: Ranidae): Cellular profiles and associated Th1 skewed cytokine response

    Energy Technology Data Exchange (ETDEWEB)

    Jayawardena, Uthpala A.; Ratnasooriya, Wanigasekara D.; Wickramasinghe, Deepthi D.; Udagama, Preethi V., E-mail: dappvr@yahoo.com

    2016-10-01

    Immune cell and cytokine profiles in relation to metal exposure though much studied in mammals has not been adequately investigated in amphibians, due mainly to lack of suitable reagents for cytokine profiling in non-model species. However, interspecies cross reactivity of cytokines permitted us to assay levels of IFNγ, TNFα, IL6 and IL10in a common anuran, the Indian green frog (Euphlyctis hexadactylus), exposed to heavy metals (Cd, Cr, Cu, Zn and Pb, at ~ 5 ppm each) under field and laboratory settings in Sri Lanka. Enumeration of immune cells in blood and melanomacrophages in the liver, assay of serum and hepatic cytokines, and Th1/Th2 cytokine polarisation were investigated. Immune cell counts indicated overall immunosuppression with decreasing total WBC and splenocyte counts while neutrophil/lymphocyte ratio increased with metal exposure, indicating metal mediated stress. Serum IL6 levels of metal exposed frogs reported the highest (~ 9360 pg/mL) of all cytokines tested. Significantly elevated IFNγ production (P < 0.05) was evident in heavy metal exposed frogs. Th1/Th2 cytokine ratio in both serum and liver tissue homogenates was Th1 skewed due to significantly higher production of pro-inflammatory cytokines, IFNγ in serum and TNFα in the liver (P < 0.01).Metal mediated aggregations of melanomacrophages in the liver were positively and significantly (P < 0.05) correlated with the hepatic expression of TNFα, IL6 and IL10 activity. Overall, Th1 skewed response may well be due to oxidative stress mediated nuclear factor κ-light chain enhancer of activated B cells (NFκB) which enhances the transcription of pro-inflammatory cytokines. Xenobiotic stress has recently imposed an unprecedented level of threat to wildlife, particularly to sensitive species such as amphibians. Therefore, understanding the interactions between physiological stress and related immune responses is fundamental to conserve these environmental sentinels in the face of emerging eco

  20. Evaluation of Pseudomonas aeruginosa an innovative bioremediation tool in multi metals ions from simulated system using multi response methodology.

    Science.gov (United States)

    Singh, Rajesh; Bishnoi, Narsi R; Kirrolia, Anita

    2013-06-01

    Under certain conditions bacteria can act as a good biosorbent towards heavy metals in simultaneous removal from effluents. The present study explores overlay plots of multi response surface methodology for simulated wastewater treatment potential. Pseudomonas aeruginosa was used for bioremediation of metallic ions, where removal of Cd (80-90%), Mn (85-90%), Fe (50-55%), Cr (70-75%) can be achieved by fixing the pH, oxidation reduction potential (mV) and one of the metallic constituent in the simulated effluent. The metal ions Cd and Cr (T), Fe and ORP (mV) are relatively closely located to each other in the loading plot indicating co-variance between these components. However Cr(VI) transformation and Mn removal are distantly placed in the bi-plot indicating the existed significant difference. Elevated reductase enzyme activity (31.75 μg/minmg) observed in the isolate showing the ability to effectively reduce metals ions.

  1. Shock Wave Response of Iron-based In Situ Metallic Glass Matrix Composites

    Science.gov (United States)

    Khanolkar, Gauri R.; Rauls, Michael B.; Kelly, James P.; Graeve, Olivia A.; Hodge, Andrea M.; Eliasson, Veronica

    2016-03-01

    The response of amorphous steels to shock wave compression has been explored for the first time. Further, the effect of partial devitrification on the shock response of bulk metallic glasses is examined by conducting experiments on two iron-based in situ metallic glass matrix composites, containing varying amounts of crystalline precipitates, both with initial composition Fe49.7Cr17.7Mn1.9Mo7.4W1.6B15.2C3.8Si2.4. The samples, designated SAM2X5-600 and SAM2X5-630, are X-ray amorphous and partially crystalline, respectively, due to differences in sintering parameters during sample preparation. Shock response is determined by making velocity measurements using interferometry techniques at the rear free surface of the samples, which have been subjected to impact from a high-velocity projectile launched from a powder gun. Experiments have yielded results indicating a Hugoniot Elastic Limit (HEL) to be 8.58 ± 0.53 GPa for SAM2X5-600 and 11.76 ± 1.26 GPa for SAM2X5-630. The latter HEL result is higher than elastic limits for any BMG reported in the literature thus far. SAM2X5-600 catastrophically loses post-yield strength whereas SAM2X5-630, while showing some strain-softening, retains strength beyond the HEL. The presence of crystallinity within the amorphous matrix is thus seen to significantly aid in strengthening the material as well as preserving material strength beyond yielding.

  2. Legal aspects of electric power supply. Grid operator obligations between entrepreneurial responsibility and state control; Das Recht der Elektrizitaetsversorgungsnetze. Netzbetreiberpflichten zwischen unternehmerischer Eigenverantwortung und staatlicher Steuerung

    Energy Technology Data Exchange (ETDEWEB)

    Maetzig, Karoline

    2012-07-01

    The publication provides a systematic outline of the legal boundary conditions governing the operation of electric power supply grids. It goes beyond mere regulatory aspects, covering also the projecting and construction of grids, the acquisition or leasing of land for power transmission line construction, operating licenses and utility certification, the organisational structure and purpose of electric utilities, as well as the operating, servicing and enhancement of electricity grids including calculation of electricity rates. In addition to this systematic outline of legal aspects, it is investigated how the balance between entrepreneurial responsibility and state control was defined in the EnWG 2011, and it is discussed if the law provides sufficient room for entrepreneurial decisions.

  3. Essays on sustainable supply management

    NARCIS (Netherlands)

    Koster, H.R.

    2014-01-01

    The growing concern for organizations’ social responsibility and sustainable behavior has been accompanied by considerable awareness of how organizations manage their supply chains. For many organizations, a large proportion of their sustainability impact comes from their inbound supply chain, an ar

  4. The response of the TonB-dependent transport network in Anabaena sp. PCC 7120 to cell density and metal availability.

    Science.gov (United States)

    Stevanovic, Mara; Lehmann, Christina; Schleiff, Enrico

    2013-08-01

    TonB dependent transporters (TBDT) are an essential protein family in bacteria involved in the uptake of a broad variety of molecules such as siderophore-chelated iron, which was the first described substrate. Meanwhile it is known that TBDTs are involved in the uptake of many metals, sugars and polypeptides. The action of TBDTs is regulated and energized by the plasma membrane anchored TonB, which is charged by a proton pump. The number of the genes coding for TBDTs varies in different species, which might reflect environmental adaptations or evolutionary variations of the system. For example, in the cyanobacterium Anabaena sp. PCC 7120 the large number of 22 genes coding for TBDTs has been identified and the expression of these genes has been explored in the absence of iron or copper as well as under nitrogen starvation. We describe the analysis of the expression of the TBDT genes and the according cytoplasmic-membrane localized components; the latter appear to have a lower degree of complexity in Anabaena sp. PCC 7120. This analysis unravels that the response is not sole dependent on the metal supply, but also on cell culture densities. In addition, we present a large group of FhuA-like genes which is expressed highest under standard conditions suggesting a function distinct from iron or copper transport. The genes are clustered according to the expression profile and the consequences for our understanding of the transport systems in Anabaena sp. PCC 7120 are discussed.

  5. The comparisons of lot sizes and costs based on the different bodies responsible for supply -hub operations%不同Supply—hub营运主体下的批量与成本比较研究

    Institute of Scientific and Technical Information of China (English)

    桂华明; 马士华

    2012-01-01

    The supply pattern based on supply -hub under the Just -In -Time (JIT) environment is considered, and the average cost function of manufacturer, supply - huh, and supplier is established. Moreover, the production and order lot - size models of the supply - hub operation and cost, which manufacturer and supplier are responsible for, respectively, are proposed. The results show that under the condition that supply - hub is appropriate,it is more favorable to the supplier than to the manufacturer when the supplier is responsible for supply - hub operation and cost comparing with the manufacturer is responsible for, but the total cost of the supply chain is reduced. It is able to reduce the costs of the manufacturer and the supplier on certain level through negotiations and interest transfer, therefore entire supply chain is achieved Pareto optimization; Moreover, with the distance between the supplier and supply - hub is the further, it is more favorable to the supply chain when the supplier is responsible for supply - hub operation and cost rather than the manufacturer is responsible for that.%本文考虑了JIT环境下基于Supply—hub的供货模式,建立了制造商、Supply—hub和供应商的平均成本函数,并提出了分别由制造商和供应商负责Supply—hub营运及成本的生产与订货批量模型。结果表明,在Supply—hub适用的条件下,相比由制造商负责,供应商负责Supply—hub的运营及成本时,对供应商有利而不利于制造商,但整个供应链的总成本减少,通过供应商与制造商之间的协商和利益转移,可以使制造商和供应商的成本都有所减少,从而实现整个供应链的Pareto优化,此外,供应商距离Supply—hub越远,相比制造商负责,由供应商负责Supply—hub的营运及成本对整个供应链更有利。

  6. Comparative sodium transport patterns provide clues for understanding salinity and metal responses in aquatic insects.

    Science.gov (United States)

    Scheibener, S A; Richardi, V S; Buchwalter, D B

    2016-02-01

    The importance of insects in freshwater ecosystems has led to their extensive use in ecological monitoring programs. As freshwater systems are increasingly challenged by salinization and metal contamination, it is important to understand fundamental aspects of aquatic insect physiology (e.g., osmoregulatory processes) that contribute to insect responses to these stressors. Here we compared the uptake dynamics of Na as NaCl, NaHCO3 and Na2SO4 in the caddisfly Hydropsyche betteni across a range of Na concentrations (0.06-15.22 mM) encompassing the vast majority of North American freshwater ecosystems. Sulfate as the major anion resulted in decreased Na uptake rates relative to the chloride and bicarbonate salts. A comparison of Na (as NaHCO3) turnover rates in the caddisfly Hydropsyche sparna and the mayfly Maccaffertium sp. revealed different patterns in the 2 species. Both species appeared to tightly regulate their whole body sodium concentrations (at ∼47±1.8 μmol/g wet wt) across a range of Na concentrations (0.06-15.22 mM) over 7 days. However, at the highest Na concentration (15.22 mM), Na uptake rates in H. sparna (419.1 μM Na g(-1) hr(-1) wet wt) appeared close to saturation while Na uptake rates in Maccaffertium sp. were considerably faster (715 g μM Na g(-1) hr(-1) wet wt) and appeared to not be close to saturation. Na efflux studies in H. sparna revealed that loss rates are commensurate with uptake rates and are responsive to changes in water Na concentrations. A comparison of Na uptake rates (at 0.57 mM Na) across 9 species representing 4 major orders (Ephemeroptera, Plecoptera, Trichoptera and Diptera) demonstrated profound physiological differences across species after accounting for the influence of body weight. Faster Na uptake rates were associated with species described as being sensitive to salinization in field studies. The metals silver (Ag) and copper (Cu), known to be antagonistic to Na uptake in other aquatic taxa did not generally

  7. Physiological responses of Tillandsia albida (Bromeliaceae) to long-term foliar metal application

    Energy Technology Data Exchange (ETDEWEB)

    Kovacik, Jozef, E-mail: jozkovacik@yahoo.com [Institute of Chemistry and Biochemistry, Faculty of Agronomy, Mendel University in Brno, Zemedelska 1, 613 00 Brno (Czech Republic); CEITEC - Central European Institute of Technology, Mendel University in Brno, Zemedelska 1, 613 00 Brno (Czech Republic); Klejdus, Borivoj [Institute of Chemistry and Biochemistry, Faculty of Agronomy, Mendel University in Brno, Zemedelska 1, 613 00 Brno (Czech Republic); CEITEC - Central European Institute of Technology, Mendel University in Brno, Zemedelska 1, 613 00 Brno (Czech Republic); Stork, Frantisek [Department of Botany, Institute of Biology and Ecology, Faculty of Science, P. J. Safarik University, Manesova 23, 041 67 Kosice (Slovakia); Hedbavny, Josef [Institute of Chemistry and Biochemistry, Faculty of Agronomy, Mendel University in Brno, Zemedelska 1, 613 00 Brno (Czech Republic)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer Impact of foliar Cd, Ni and Cd + Ni application on Tillandsia albida was studied. Black-Right-Pointing-Pointer Cd caused visible damage and enhanced stress parameters in combined treatment. Black-Right-Pointing-Pointer Nitrogenous compounds were slightly affected but phenols were up- and down-regulated. Black-Right-Pointing-Pointer Mineral nutrients (K, Ca, Na, Mg, Fe, and Zn) were not affected by any of treatments. Black-Right-Pointing-Pointer Total Cd or Ni reached ca. 0.04% and Ni was more absorbed than Cd. - Abstract: The impact of 2-month foliar application of cadmium, nickel and their combination (10 {mu}M) on Tillandsia albida was studied. Cadmium caused damage of tissue but assimilation pigments were depressed in Cd + Ni variant only. Stress-related parameters (ROS and peroxidase activities) were elevated by Cd and Cd + Ni while MDA content remained unaffected. Free amino acids accumulated the most in Ni alone but soluble proteins were not influenced. Among phenolic acids, mainly vanillin contributed to increase of their sum in all variants while soluble phenols even decreased in Cd + Ni and flavonols slightly increased in Cd variants. Phenolic enzymes showed negligible responses to almost all treatments. Mineral nutrients (K, Ca, Na, Mg, Fe, and Zn) were not affected by metal application but N content increased. Total Cd or Ni amounts reached over 400 {mu}g g{sup -1} DW and were not affected if metal alone and combined treatment is compared while absorbed content differed (ca. 50% of total Cd was absorbed while almost all Ni was absorbed). These data indicate tolerance of T. albida to foliar metal application and together with strong xerophytic morphology, use for environmental studies is recommended.

  8. Characterization and localization of metal-responsive-element-binding transcription factors from tilapia

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, Andrew Pok-Lap; Au, Candy Yee-Man; Chan, William Wai-Lun [Department of Biochemistry, Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong (Hong Kong); Chan, King Ming, E-mail: kingchan@cuhk.edu.hk [Department of Biochemistry, Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong (Hong Kong)

    2010-08-01

    Two isoforms of MTF-1, MTF-1L (long form) and MTF-1S (short form), were cloned in tilapia (Ti) and characterized in a tilapia liver cell line, Hepa-T1. The cloned tiMTF-1L has the characteristics of all of the tiMTF-1S identified so far with the zinc finger domain having six fingers, the acidic-rich, proline-rich, and serine/threonine-rich domains; however, the short form encodes for the zinc finger domain with five zinc fingers only and no other domains. The transient transfection of tiMTF-1L into human HepG2 cells showed both constitutive and zinc-induced metal-responsive-element (MRE)-driven reporter gene expression. However, the transfection of tiMTF-1S (which lacks all three transactivation domains) into a human cell line showed reduced transcriptional activities compared with an endogenous control in both basal- and Zn{sup 2+}-induced conditions. The tiMTF-1 isoforms were tagged with GFP and transfected into Hepa-T1 cells (tilapia hepatocytes). The nuclear translocation of tiMTF-1L was observed when the cells were exposed to a sufficient concentration of metals for 6 h. However, tiMTF-1S, was localized in the nucleus with or without metal treatment. Electrophoretic mobility shift assay (EMSA) confirmed that both of the isoforms were able to bind to the MRE specifically in vitro. Tissue distribution studies showed that tiMTF-1L was more abundant than tiMTF-1S in all of the tissues tested.

  9. Temperature responsive hydrogel magnetic nanocomposites for hyperthermia and metal extraction applications

    Science.gov (United States)

    Reddy, N. Narayana; Ravindra, S.; Reddy, N. Madhava; Rajinikanth, V.; Raju, K. Mohana; Vallabhapurapu, Vijaya Srinivasu

    2015-11-01

    The present work deals with the development of temperature and magnetic responsive hydrogel networks based on poly (N-isopropylacrylamide)/acrylamido propane sulfonic acid. The hydrogel matrices are synthesized by polymerizing N-isopropylacrylamide (NIPAM) monomer in the presence of acrylamido propane sulphonicacid (AMPS) using a cross-linker (N,N-methylenebisacrylamide, MBA) and redox initiating system [ammonium persulphate (APS)/tetramethylethylenediamine (TMEDA)]. The magnetic nanoparticles are generated throughout the hydrogel networks using in situ method by incorporating iron ions and subsequent treatment with ammonia. A series of hydrogel-magnetic nanocomposites (HGMNC) are developed by varying AMPS composition. The synthesized hydrogel magnetic nanocomposites (HGMNC) are characterized by using Fourier Transform Infrared (FTIR) Spectroscopy, X-ray diffraction (XRD), Thermal Analyses and Electron Microscopy analysis (Scanning and Transmission Electron Microscope). The metal extraction capacities of the prepared hydrogel (HG) and hydrogel magnetic nanocomposites (HGMNC) were studied at different temperatures. The results suggest that HGMNCs have higher extraction capacity compared to HG and HG loaded iron ions. This data also reveals that the extraction of metals by hydrogel magnetic nanocomposites (HGMNCs) is higher at higher temperatures than room temperature. The prepared HGMNCs are also subjected to hyperthermia (cancer therapy) studies.

  10. Co-sputtered metal and polymer nanocomposite films and their electrical responses for gas sensing application

    Science.gov (United States)

    Rujisamphan, Nopporn; Murray, Roy E.; Deng, Fei; Supasai, Thidarat

    2016-04-01

    Titanium and polytetrafluoroethylene (Ti-PTFE) nanocomposite thin films were successfully fabricated on glass substrates using a combination of dc and rf magnetron sputtering. When the Ti-PTFE composites were prepared at below the percolation threshold i.e. 27% metal volume filling (F), Ti clusters with the average sizes of 7 ± 2 nm were found. As the Ti content was increased above the percolation threshold (F = 62%), the connecting regions of Ti were formed within the polymer matrix and the electrical property changed rapidly from insulator-like to metal-like properties. The Ti-PTFE composites prepared near the percolation threshold showed the electrical response to different volatile organic compounds (VOCs). The sensitivity significantly depended upon the VOCs concentrations. These composites devices showed the presence of distinct chemical bonds of Csbnd C, Csbnd CF, Csbnd F and CF2 and TiF in TiO2 on the surface as investigated by X-ray photoelectron spectroscopy (XPS) while the surface morphology, characterized by atomic force microscopy (AFM) presented the root mean square (RMS) surface roughness of 13.3 nm. Cross-section transmission electron microscopy (TEM) images of the device revealed Ti clusters dispersed in PTFE matrix with particle sizes varied between 10 nm and 30 nm.

  11. A Stimuli-Responsive Zirconium Metal-Organic Framework Based on Supermolecular Design.

    Science.gov (United States)

    Krause, Simon; Bon, Volodymyr; Stoeck, Ulrich; Senkovska, Irena; Többens, Daniel M; Wallacher, Dirk; Kaskel, Stefan

    2017-08-28

    A flexible, yet very stable metal-organic framework (DUT-98, Zr6 O4 (OH)4 (CPCDC)4 (H2 O)4 , CPCDC=9-(4-carboxyphenyl)-9H-carbazole-3,6-dicarboxylate) was synthesized using a rational supermolecular building block approach based on molecular modelling of metal-organic chains and subsequent virtual interlinking into a 3D MOF. Structural characterization via synchrotron single-crystal X-ray diffraction (SCXRD) revealed the one-dimensional pore architecture of DUT-98, envisioned in silico. After supercritical solvent extraction, distinctive responses towards various gases stimulated reversible structural transformations, as detected using coupled synchrotron diffraction and physisorption techniques. DUT-98 shows a surprisingly low water uptake but a high selectivity for pore opening towards specific gases and vapors (N2 , CO2 , n-butane, alcohols) at characteristic pressure resulting in multiple steps in the adsorption isotherm and hysteretic behavior upon desorption. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Characterizing and modeling electrical response to light for metal-based EUV photoresists

    Science.gov (United States)

    Pret, Alessandro V.; Kocsis, Mike; De Simone, Danilo; Vandenberghe, Geert; Stowers, Jason; Giglia, Angelo; de Schepper, Peter; Mani, Antonio; Biafore, John J.

    2016-03-01

    Metal-based photoresists are appealing for use in EUV lithography due to their improved etch resistance and absorption compared with organic resists, and due to their resolving power demonstrated with 13.53 nm exposures using synchrotron light. Recently imec has started a new project to study novel photoresists for EUV lithography, with particular attention to metal containing materials, in order to explore alternative approaches that may offer superior characteristics in photoresist imaging and etching performance compared with more mature chemically amplified resists. In order to model these novel resists it is mandatory to understand both the optical properties and the electronic response to photon absorption. As in previous experiments on organic materials, some of the optical properties can be determined by merging analysis from high-energy electron scattering models (e.g. CXRO website), X-ray absorption spectroscopy, and DUV spectroscopic ellipsometry. Dispersion curves can be used to calculate the electronic inelastic and elastic mean-free paths; convolved with the expected spectrum at wafer level it is possible to estimate the electron yield and the secondary electron blur of the photoresist. These material properties can be used to modify the physical models currently used to simulate organic photoresist performance in computational lithography software.

  13. Developing sustainable food supply chains.

    Science.gov (United States)

    Smith, B Gail

    2008-02-27

    This paper reviews the opportunities available for food businesses to encourage consumers to eat healthier and more nutritious diets, to invest in more sustainable manufacturing and distribution systems and to develop procurement systems based on more sustainable forms of agriculture. The important factors in developing more sustainable supply chains are identified as the type of supply chain involved and the individual business attitude to extending responsibility for product quality into social and environmental performance within their own supply chains. Interpersonal trust and working to standards are both important to build more sustainable local and many conserved food supply chains, but inadequate to transform mainstream agriculture and raw material supplies to the manufactured and commodity food markets. Cooperation among food manufacturers, retailers, NGOs, governmental and farmers' organizations is vital in order to raise standards for some supply chains and to enable farmers to adopt more sustainable agricultural practices.

  14. Photovoltaic Response from Multilayered Transition Metal Dichalcogenides p-n Junctions

    Science.gov (United States)

    Memaran, Shahriar; Pradhan, Nihar; Lu, Zhengguang; Rhodes, Daniel; Ludwig, Jonathan; Zhou, Qiong; Ogunsolu, Omotola; Ajayan, Pulickel; Smirnov, Dmitry; Fernandez-Dominguez, Antonio; Garcia-Vidal, Francisco; Balicas, Luis

    Transition metal dichalcogenides (TMDs) are layered semiconductors with indirect band gaps comparable to Si. These compounds can be grown in large area, while their gap(s) can be tuned by changing their chemical composition or by applying a gate voltage. The experimental evidence collected so far points toward a strong interaction with light, which contrasts with the small photovoltaic efficiencies η stacked onto the dielectric h-BN. In addition to ideal diode-like response, we find that these junctions can yield, under AM-1.5 illumination, photovoltaic efficiencies η exceeding 14%, with fill factors of ~ 70 % . Given the available strategies for increasing η such as gap tuning, improving the quality of the electrical contacts, or the fabrication of tandem cells, our study suggests a remarkable potential for photovoltaic applications based on TMDs.

  15. Stimuli-Responsive Metal-Organic Frameworks with Photoswitchable Azobenzene Side Groups.

    Science.gov (United States)

    Kanj, Anemar Bruno; Müller, Kai; Heinke, Lars

    2017-07-31

    Metal-organic frameworks (MOFs) are nanoporous, crystalline hybrid materials, which enable various functionalities by incorporating functional organic molecules. By using organic linker molecules that possess photoswitchable azobenzene side groups, the remote control over certain properties was introduced to MOFs. Different MOF materials in the form of powders and thin films have been used to demonstrate the photoswitching. The applications of these stimuli-responsive nanoporous solids range from switching the adsorption capacity of various gases over remote-controlled release of guest molecules to continuously tunable membrane separation of molecular mixtures. A particular focus of this review is the effect of the azobenzene photoswitching on the host-guest interaction, enabling smart applications of the material. Steric hindrance, which may suppress the photoswitching in some MOF structures, is also discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Terahertz-induced photothermoelectric response in graphene-metal contact structures

    Science.gov (United States)

    Deng, Xiangquan; Wang, Yingxin; Zhao, Ziran; Chen, Zhiqiang; Sun, Jia-Lin

    2016-10-01

    We report on the photoresponse of a graphene-metal contact device under terahertz (THz) illumination. The device has an extremely simple structure consisting of a large-area monolayer graphene stripe contacted with two gold electrodes. A significant position-dependent photovoltage is observed across the device by THz excitation, exhibiting a linear relationship with the incident beam power. Experimental results show that the graphene channel length and the substrate thermal conductivity have obvious influence on the photovoltage amplitude and response time, which is consistent with the photothermoelectric mechanism. This compact and powerless device is expected to have a promising application in THz detection. Our work provides theoretical and experimental evidence for the development of high-performance graphene-based THz photodetectors.

  17. 中国有色金属矿产对外依存度与资源可供性之辨析%Analysis and discussion on dependency of overseas market and supply of China non-ferrous metals resources

    Institute of Scientific and Technical Information of China (English)

    杨兵

    2013-01-01

    文章分析了我国近年有色金属的生产、消费以及资源可供性等方面情况.中国是世界上最大的有色金属(一般是指铜、铝、铅、锌、镍、锡、锑、汞、镁、钛等10种常用有色金属)生产和消费国,2010年,我国有色金属产量为3136万吨,占世界产量的37%,消费量3406万吨,占世界的41.3%.文章从数据的可获取性、对外依存度的准确界定以及可比性口径要一致等几个方面来确定矿产资源领域的对外依存度,并对有色金属的对外依存度进了行分析.%The author conducts the analysis on China' s production,consumption of the non-ferrous metals and resources supply within recent years.China ranks top of the production and consumption of ten kinds of non-ferrous metals (including copper,alumina,lead,zinc,nickel,tin,antimony,mercury,magnesium,and titanium) in the world.In 2010,China produced a total of 31.36 million tons of above-mentioned non-ferrous metals,which accounts for 37% of the world production,and consumed 34.06 million of tones which accounts for 41.3% of total world' s consumption.It is analyzed the dependency of overseas supply of non-ferrous metal resources from aspects of the data collection,accurate definition of the overseas dependency and comparison,as well as the overseas dependency of the non-ferrous metals.

  18. Temperature responsive hydrogel magnetic nanocomposites for hyperthermia and metal extraction applications

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, N. Narayana, E-mail: nagireddynarayana@gmail.com [Center for Advanced Biomaterials for Healthcare, Istituto Italiano di Tecnologia@CRIB, Largo Barsanti e Matteucci 53, 80125 Napoli (Italy); Ravindra, S. [Department of Physics, College of Science, Engineering and Technology, University of South Africa, Johannesburg 1709 (South Africa); Reddy, N. Madhava [Department of Environmental Science, Gates Institute of Technology, NH-7, Gooty, Anantapuram, Andhra Pradesh (India); Rajinikanth, V. [Department of Physics, College of Science, Engineering and Technology, University of South Africa, Johannesburg 1709 (South Africa); Raju, K. Mohana [Synthetic Polymer Laboratory, Department of Polymer Science & Technology, S.K. University, Anantapuram, Andhra Pradesh (India); Vallabhapurapu, Vijaya Srinivasu [Department of Physics, College of Science, Engineering and Technology, University of South Africa, Johannesburg 1709 (South Africa)

    2015-11-15

    The present work deals with the development of temperature and magnetic responsive hydrogel networks based on poly (N-isopropylacrylamide)/acrylamido propane sulfonic acid. The hydrogel matrices are synthesized by polymerizing N-isopropylacrylamide (NIPAM) monomer in the presence of acrylamido propane sulphonicacid (AMPS) using a cross-linker (N,N-methylenebisacrylamide, MBA) and redox initiating system [ammonium persulphate (APS)/tetramethylethylenediamine (TMEDA)]. The magnetic nanoparticles are generated throughout the hydrogel networks using in situ method by incorporating iron ions and subsequent treatment with ammonia. A series of hydrogel-magnetic nanocomposites (HGMNC) are developed by varying AMPS composition. The synthesized hydrogel magnetic nanocomposites (HGMNC) are characterized by using Fourier Transform Infrared (FTIR) Spectroscopy, X-ray diffraction (XRD), Thermal Analyses and Electron Microscopy analysis (Scanning and Transmission Electron Microscope). The metal extraction capacities of the prepared hydrogel (HG) and hydrogel magnetic nanocomposites (HGMNC) were studied at different temperatures. The results suggest that HGMNCs have higher extraction capacity compared to HG and HG loaded iron ions. This data also reveals that the extraction of metals by hydrogel magnetic nanocomposites (HGMNCs) is higher at higher temperatures than room temperature. The prepared HGMNCs are also subjected to hyperthermia (cancer therapy) studies. - Highlights: • We have developed temperature responsive hydrogel magnetic nanocomposites. • Addition of AMPS monomer to this magnetic hydrogel enhances the temperature sensitivity to 40–43 °C. • Similarly the sulfonic groups present in the AMPS units enhances the swelling ratio of magnetic hydrogels. • AMPS acts as good stabilizing agent for nanoparticles in the magnetic nanogel.

  19. 基于熵模型的供电企业社会责任测评体系初探%Exploration on Power Supply Corporation Social Responsibility Evaluation System Based on Entropy Model

    Institute of Scientific and Technical Information of China (English)

    谭术

    2013-01-01

    Combining the characteristics of the electricity supply industry, as well as social, environmental and other stakeholders, it puts forward new requirements for its environmental protection and energy saving, ecological balance, improved employment, production safety, high-quality power supply and other aspects. The social responsibility of power supply corporation is divided into market responsibility, the management of responsibility, moral responsibility, ethical responsibility, environmental responsibility and design indicators and econometric models, so as to provide a basis for evaluation and realistic guidance for power supply enterprises to fulfill their social responsibility.%  文章结合供电行业的特点,以及社会、环境等利益相关者对其环保节能、生态平衡、促进就业、安全生产、优质供电等方面提出的新要求,将供电企业的社会责任分为市场责任、责任管理、道德责任、伦理责任、环境责任五大类,并设计指标和计量模型,为供电企业履行社会责任提供评价依据和现实指导。

  20. Effect of nitrogen supply and Azospirillum brasilense Sp-248 on the response of wheat to seawater irrigation.

    Science.gov (United States)

    Alamri, Saad A; Mostafa, Yasser S

    2009-10-01

    Response of wheat to Azospirillum brasilense Sp-248 inoculation with different N-fertilizer levels using seawater irrigation was investigated. All inoculated treatments increased plant height, shoot and root dry weight, and tiller number in compared with uninoculated treatments. Yield parameters measured were also increased due to the inoculation. In terms of the effect of saline irrigation, there were no significant differences in growth and yield parameters in plants treated with tap water and others irrigated with 8.0% seawater concentration. This would indicate a relatively high tolerance of A. brasilense to saline irrigation and its ability to reduce the deleterious effects of saline on growth by increasing the plant's adaptation. However, increasing the seawater concentration in the irrigation water to 16.0% significantly decreased all tested parameters. Inoculation treatments generally increased NPKCa contents and decreased sodium ratio of the grains in compared with the uninoculated treatments. Overall results clearly revealed that the Azospirillum inoculation saved about 20 units of N-fertilizer and that saving was made economically feasible by decreasing the chemical fertilizers needed, improving the nitrogen content and counteracting the effects of salinity.

  1. Metal accumulation and oxidative stress responses in Ulva spp. in the presence of nocturnal pulses of metals from sediment: A field transplantation experiment under eutrophic conditions

    KAUST Repository

    Pereira, Patrícia M R

    2014-03-01

    In aquatic systems under eutrophic conditions, remobilization of metals from sediment to the overlying water may occur. Consequently, adaptive responses of local organisms could result from the accumulation of metals intermittently released from the sediment. In summer 2007, a field transplantation experiment was performed in the Óbidos lagoon (Portugal) with Ulva spp. comprising three short-term exposures (between 15:30-23:30; 23:30-07:30; 07:30-15:30) during a 24-h period. In each period, Ulva spp. was collected at a reference site located in the lower lagoon (LL) and transplanted to a eutrophic site located at the Barrosa branch (BB), characterized by moderate metal contamination. For comparison purposes, macroalgae samples were simultaneously exposed at LL under the same conditions. Both sites were surveyed in short-time scales (2-4 h) for the analysis of the variability of physical-chemical parameters in the water and metal levels in suspended particulate matter. The ratios to Al of particulate Mn, Fe, Cu and Pb increased during the period of lower water oxygenation at the eutrophic site, reaching 751 × 10-4, 0.67, 12 × 10-4, 9.9 × 10-4, respectively, confirming the release of metals from the sediment to water during the night. At the reference site, dissolved oxygen oscillated around 100%, Mn/Al ratios were considerably lower (81 × 10-4-301 × 10-4) compared to BB (234 × 10-4-790 × 10-4), and no increases of metal/Al ratios were found during the night. In general, algae uptake of Mn, Cu, Fe, Pb and Cd was significantly higher at the eutrophic site compared to the reference site. The results confirmed the potential of Ulva spp. as bioindicator of metal contamination and its capability to respond within short periods. An induction of SOD, an inhibition of CAT and the increase of LPO were recorded in Ulva spp. exposed at BB (between 23:30 and 7:30) probably as a response to the higher incorporation of Mn, Fe and Pb in combination with the lack of

  2. Heavy Metals Affect Nematocysts Discharge Response and Biological Activity of Crude Venom in the Jellyfish Pelagia noctiluca (Cnidaria, Scyphozoa

    Directory of Open Access Journals (Sweden)

    Rossana Morabito

    2014-07-01

    Full Text Available Background: Pollution of marine ecosystems and, specifically, heavy metals contamination may compromise the physiology of marine animals with events occurring on a cellular and molecular level. The present study focuses on the effect of short-term exposure to heavy metals like Zinc, Cadmium, Cobalt and Lanthanum (2-10 mM on the homeostasis of Pelagia noctiluca (Cnidaria, Scyphozoa, a jellyfish abundant in the Mediterranean sea. This species possesses stinging organoids, termed nematocysts, whose discharge and concomitant delivery of venom underlie the survival of all Cnidaria. Methods: Nematocysts discharge response, elicited by combined chemico-physical stimulation, was verified on excised oral arms exposed to heavy metals for 20 min. In addition, the hemolytic activity of toxins, contained in the crude venom extracted from nematocysts isolated from oral arms, was tested on human erythrocytes, in the presence of heavy metals or their mixture. Results: Treatment with heavy metals significantly inhibited both nematocysts discharge response and hemolytic activity of crude venom, in a dose-dependent manner, not involving oxidative events, that was irreversible in the case of Lanthanum. Conclusion: Our findings show that the homeostasis of Pelagia noctiluca, in terms of nematocysts discharge capability and effectiveness of venom toxins, is dramatically and rapidly compromised by heavy metals and confirm that this jellyfish is eligible as a model for ecotoxicological investigations.

  3. Algal photosynthetic responses to toxic metals and herbicides assessed by chlorophyll a fluorescence.

    Science.gov (United States)

    Kumar, K Suresh; Dahms, Hans-Uwe; Lee, Jae-Seong; Kim, Hyung Chul; Lee, Won Chan; Shin, Kyung-Hoon

    2014-06-01

    Chlorophyll a fluorescence is established as a rapid, non-intrusive technique to monitor photosynthetic performance of plants and algae, as well as to analyze their protective responses. Apart from its utility in determining the physiological status of photosynthesizers in the natural environment, chlorophyll a fluorescence-based methods are applied in ecophysiological and toxicological studies to examine the effect of environmental changes and pollutants on plants and algae (microalgae and seaweeds). Pollutants or environmental changes cause alteration of the photosynthetic capacity which could be evaluated by fluorescence kinetics. Hence, evaluating key fluorescence parameters and assessing photosynthetic performances would provide an insight regarding the probable causes of changes in photosynthetic performances. This technique quintessentially provides non-invasive determination of changes in the photosynthetic apparatus prior to the appearance of visible damage. It is reliable, economically feasible, time-saving, highly sensitive, versatile, accurate, non-invasive and portable; thereby comprising an excellent alternative for detecting pollution. The present review demonstrates the applicability of chlorophyll a fluorescence in determining photochemical responses of algae exposed to environmental toxicants (such as toxic metals and herbicides). Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Machining Performance Study on Metal Matrix Composites-A Response Surface Methodology Approach

    Directory of Open Access Journals (Sweden)

    A. Srinivasan

    2012-01-01

    Full Text Available Problem statement: Metal Matrix Composites (MMC have become a leading material among composite materials and in particular, particle reinforced aluminum MMCs have received considerable attention due to their excellent engineering properties. These materials are known as the difficult-to-machine materials because of the hardness and abrasive nature of reinforcement element-like Alumina (Al2O3. Approach: In this study, an attempt has been made to model the machinability evaluation through the response surface methodology in machining of homogenized 10% micron Al2O3 LM25 Al MMC manufactured through stir casting method. Results: The combined effects of three machining parameters including cutting speed (s, feed rate (f and depth of cut (d on the basis of three performance characteristics of tool wear (VB, surface Roughness (Ra and cutting Force (Fz were investigated. The contour plots were generated to study the effect of process parameters as well as their interactions. Conclusion: The process parameters are optimized using desirability-based approach response surface methodology.

  5. Heavy metal contamination and hepatic toxicological responses in brown trout (Salmo trutta from the Kerguelen Islands

    Directory of Open Access Journals (Sweden)

    Ali Jaffal

    2015-09-01

    Full Text Available The Kerguelen Islands include various species of freshwater fish such as brown trout (Salmo trutta. These trout are among the most isolated from direct anthropogenic impact worldwide. This study was designed to analyse cadmium (Cd and copper (Cu concentrations in the liver of Kerguelen brown trout, and to assess the possible impacts of these metals on hepatic histopathology and oxidative stress parameters (superoxide dismutase and catalase activity and glutathione levels. Trout were caught in the Château River, the Studer Lakes and the Ferme Pond, close to the scientific station of the Kerguelen Islands, corresponding to three morphotypes (river, lake and station. Kerguelen trouts’ hepatic concentrations of Cd and Cur were similar to those reported in previous studies in salmonids populations from areas under anthropological impacts. Clear hepatic disturbances (fibrosis, nuclear alteration, increased immune response, melanomacrophage centres [MMCs] were observed in all tested trout. A similar histo-pathological trend was observed among the trout from the three morphotypes but anti-oxidative responses were higher in the trout from the “station” morphotype. Hepatic alterations and the presence of MMCs in the livers of Kerguelen brown trout may be related to the high levels of Cd and Cu measured in this fish at all sampling sites.

  6. Metal oxide nanoparticles interact with immune cells and activate different cellular responses

    Directory of Open Access Journals (Sweden)

    Simón-Vázquez R

    2016-09-01

    Full Text Available Rosana Simón-Vázquez, Tamara Lozano-Fernández, Angela Dávila-Grana, Africa González-Fernández Immunology Laboratory, Biomedical Research Center (CINBIO and Institute of Biomedical Research of Ourense-Pontevedra-Vigo (IBI, University of Vigo, Campus Lagoas Marcosende, Vigo, Pontevedra, Spain Abstract: Besides cell death, nanoparticles (Nps can induce other cellular responses such as inflammation. The potential immune response mediated by the exposure of human lymphoid cells to metal oxide Nps (moNps was characterized using four different moNps (CeO2, TiO2, Al2O3, and ZnO to study the three most relevant mitogen-activated protein kinase subfamilies and the nuclear factor kappa-light-chain-enhancer of the activated B-cell inhibitor, IκBα, as well as the expression of several genes by immune cells incubated with these Nps. The moNps activated different signaling pathways and altered the gene expression in human lymphocyte cells. The ZnO Nps were the most active and the release of Zn2+ ions was the main mechanism of toxicity. CeO2 Nps induced the smallest changes in gene expression and in the IκBα protein. The effects of the particles were strongly dependent on the type and concentration of the Nps and on the cell activation status prior to Np exposure. Keywords: Jurkat, MAPK, NFκB, qPCR, inflammation, metabolism

  7. Dynamic Response and Optimal Design of Curved Metallic Sandwich Panels under Blast Loading

    Directory of Open Access Journals (Sweden)

    Chang Qi

    2014-01-01

    Full Text Available It is important to understand the effect of curvature on the blast response of curved structures so as to seek the optimal configurations of such structures with improved blast resistance. In this study, the dynamic response and protective performance of a type of curved metallic sandwich panel subjected to air blast loading were examined using LS-DYNA. The numerical methods were validated using experimental data in the literature. The curved panel consisted of an aluminum alloy outer face and a rolled homogeneous armour (RHA steel inner face in addition to a closed-cell aluminum foam core. The results showed that the configuration of a “soft” outer face and a “hard” inner face worked well for the curved sandwich panel against air blast loading in terms of maximum deflection (MaxD and energy absorption. The panel curvature was found to have a monotonic effect on the specific energy absorption (SEA and a nonmonotonic effect on the MaxD of the panel. Based on artificial neural network (ANN metamodels, multiobjective optimization designs of the panel were carried out. The optimization results revealed the trade-off relationships between the blast-resistant and the lightweight objectives and showed the great use of Pareto front in such design circumstances.

  8. Dynamic response and optimal design of curved metallic sandwich panels under blast loading.

    Science.gov (United States)

    Qi, Chang; Yang, Shu; Yang, Li-Jun; Han, Shou-Hong; Lu, Zhen-Hua

    2014-01-01

    It is important to understand the effect of curvature on the blast response of curved structures so as to seek the optimal configurations of such structures with improved blast resistance. In this study, the dynamic response and protective performance of a type of curved metallic sandwich panel subjected to air blast loading were examined using LS-DYNA. The numerical methods were validated using experimental data in the literature. The curved panel consisted of an aluminum alloy outer face and a rolled homogeneous armour (RHA) steel inner face in addition to a closed-cell aluminum foam core. The results showed that the configuration of a "soft" outer face and a "hard" inner face worked well for the curved sandwich panel against air blast loading in terms of maximum deflection (MaxD) and energy absorption. The panel curvature was found to have a monotonic effect on the specific energy absorption (SEA) and a nonmonotonic effect on the MaxD of the panel. Based on artificial neural network (ANN) metamodels, multiobjective optimization designs of the panel were carried out. The optimization results revealed the trade-off relationships between the blast-resistant and the lightweight objectives and showed the great use of Pareto front in such design circumstances.

  9. Process optimization via response surface methodology in the treatment of metal working industry wastewater with electrocoagulation.

    Science.gov (United States)

    Guvenc, Senem Yazici; Okut, Yusuf; Ozak, Mert; Haktanir, Birsu; Bilgili, Mehmet Sinan

    2017-02-01

    In this study, process parameters in chemical oxygen demand (COD) and turbidity removal from metal working industry (MWI) wastewater were optimized by electrocoagulation (EC) using aluminum, iron and steel electrodes. The effects of process variables on COD and turbidity were investigated by developing a mathematical model using central composite design method, which is one of the response surface methodologies. Variance analysis was conducted to identify the interaction between process variables and model responses and the optimum conditions for the COD and turbidity removal. Second-order regression models were developed via the Statgraphics Centurion XVI.I software program to predict COD and turbidity removal efficiencies. Under the optimum conditions, removal efficiencies obtained from aluminum electrodes were found to be 76.72% for COD and 99.97% for turbidity, while the removal efficiencies obtained from iron electrodes were found to be 76.55% for COD and 99.9% for turbidity and the removal efficiencies obtained from steel electrodes were found to be 65.75% for COD and 99.25% for turbidity. Operational costs at optimum conditions were found to be 4.83, 1.91 and 2.91 €/m(3) for aluminum, iron and steel electrodes, respectively. Iron electrode was found to be more suitable for MWI wastewater treatment in terms of operational cost and treatment efficiency.

  10. Atomic Structure and Doping Response of Grain Boundary in Transition Metal Ni

    Institute of Scientific and Technical Information of China (English)

    王崇愚; 于涛

    1994-01-01

    Based on the coincidence site lattice model and by use of the molecular dynamics method, the relaxation calculations on the atomic structures of the grain boundaries of various generating functions (∑3,∑5,…, ∑19,…,∑33) in the transition metal Ni are performed. The features of atomic structures corresponding to the grain boundaries and the effects of the pre-parameter on the interface structures are given. To study the doping response relating to the properties of materials, the 23 tilt grain boundary is selected. Based on the interstice and vacancy mechanisms, the interface responses doping boron, nitrogen and phosphorus for the grain boundary are investigated. According to the criterion of the energy in molecular dynamics simulation, the most probable positions of doping impurities and effect of doping impurities on the interface structure are given, and the dependence of the fine structure on doping type and the order of the impurity amount are obtained. The analysis of the local energy for the

  11. Pronounced Photovoltaic Response from Multilayered Transition-Metal Dichalcogenides PN-Junctions.

    Science.gov (United States)

    Memaran, Shahriar; Pradhan, Nihar R; Lu, Zhengguang; Rhodes, Daniel; Ludwig, Jonathan; Zhou, Qiong; Ogunsolu, Omotola; Ajayan, Pulickel M; Smirnov, Dmitry; Fernández-Domínguez, Antonio I; García-Vidal, Francisco J; Balicas, Luis

    2015-11-11

    Transition metal dichalcogenides (TMDs) are layered semiconductors with indirect band gaps comparable to Si. These compounds can be grown in large area, while their gap(s) can be tuned by changing their chemical composition or by applying a gate voltage. The experimental evidence collected so far points toward a strong interaction with light, which contrasts with the small photovoltaic efficiencies η ≤ 1% extracted from bulk crystals or exfoliated monolayers. Here, we evaluate the potential of these compounds by studying the photovoltaic response of electrostatically generated PN-junctions composed of approximately 10 atomic layers of MoSe2 stacked onto the dielectric h-BN. In addition to ideal diode-like response, we find that these junctions can yield, under AM-1.5 illumination, photovoltaic efficiencies η exceeding 14%, with fill factors of ~70%. Given the available strategies for increasing η such as gap tuning, improving the quality of the electrical contacts, or the fabrication of tandem cells, our study suggests a remarkable potential for photovoltaic applications based on TMDs.

  12. Effect of a metallized chamber upon the field response of a kicker magnet: simulations results and analytical calculations

    CERN Document Server

    Barnes, M J; Atanasov, M G; Kramer, T; Stadlbauer, T

    2012-01-01

    Metallized racetrack vacuum chambers will be used in the pulsed magnets of the Austrian cancer therapy and research facility, MedAustron. It is important that the metallization does not unduly degrade field rise and fall times or the flattop of the field pulse in the kicker magnets. This was of particular concern for a tune kicker magnet, which has a specified rise and fall time of 100 ns. The impact of the metallization, upon the transient field response, has been studied using Finite Element Method (FEM) simulations: the dependency of the field response to the metallization thickness and resistivity are presented in this paper and formulae for the field response, for a ramped transient excitation current, are given. An equivalent circuit for the metallization allows the effect of an arbitrary excitation to be studied, with a circuit simulator, and the circuit optimized. Furthermore, results of simulations of the effect of a magnetic brazing collar, located between the ceramic vacuum chamber and flange, of t...

  13. Study on components of rapid response capabilities of emergency medicine supply%对应急药品供应快速响应能力构成要素的探讨

    Institute of Scientific and Technical Information of China (English)

    梁建军

    2014-01-01

    目的:探讨应急药品供应快速响应能力构成要素的概念框架和构建快速响应能力的建议。方法通过分析应急药品供应存在的问题,找出应急药品供应在时效性、准确性上的需求,以及快速响应能力方面的要求。结果形成应急药材供应快速响应能力的构成要素框架,包括快速决策指挥能力、快速实施能力、快速应变能力三部分。结论构建应急药品供应快速响应能力,需从岗位练兵、信息平台建设、药品抽组方案制定、专业队伍建设多方面着手。%Objective To propose conceptual framework for the components of rapid response capabilities of emergency medi -cine supply and suggestions of rapid response capabilities establishment .Methods The components framework of rapid response capa-bilities of emergency medicine supply was proposed by analyzing the problems of emergency medicine supply and locating the demand on the timeliness and accuracy of emergency medicine supply .Results Rapid response capabilities of emergency medicine supply in-clude rapid decision-making and commanding , rapid implementation and rapid adjusting .Conclusion We should proceed from post training, information platform developing , medicine standards making , professional team building and other aspects to construct rapid response capabilities of emergency medicine supply .

  14. Co-sputtered metal and polymer nanocomposite films and their electrical responses for gas sensing application

    Energy Technology Data Exchange (ETDEWEB)

    Rujisamphan, Nopporn [Department of Physics, Faculty of Science, King Mongkut' s University of Technology Thonburi, Bangkok 10140 (Thailand); Murray, Roy E. [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Deng, Fei [Department of Materials Science and Engineering, University of Delaware, Newark, DE 19716 (United States); Supasai, Thidarat, E-mail: fscitrs@ku.ac.th [Department of Materials Science, Faculty of Science, Kasetsart University, Bangkok 10900 (Thailand)

    2016-04-15

    Graphical abstract: - Highlights: • The well-controlled Ti–PTFE composite films were prepared by co-sputtering. • Ti clusters showed particle sizes varied between 10 and 30 nm in the PTFE matrix. • The swelling of polymer is the driving force to change interparticle distance and therefore a change in resistance. • The sensitivities of the Ti–PTFE devices were found to be in a range of 1.01–1.04. - Abstract: Titanium and polytetrafluoroethylene (Ti–PTFE) nanocomposite thin films were successfully fabricated on glass substrates using a combination of dc and rf magnetron sputtering. When the Ti–PTFE composites were prepared at below the percolation threshold i.e. 27% metal volume filling (F), Ti clusters with the average sizes of 7 ± 2 nm were found. As the Ti content was increased above the percolation threshold (F = 62%), the connecting regions of Ti were formed within the polymer matrix and the electrical property changed rapidly from insulator-like to metal-like properties. The Ti–PTFE composites prepared near the percolation threshold showed the electrical response to different volatile organic compounds (VOCs). The sensitivity significantly depended upon the VOCs concentrations. These composites devices showed the presence of distinct chemical bonds of C−C, C−CF, C−F and CF{sub 2} and TiF in TiO{sub 2} on the surface as investigated by X-ray photoelectron spectroscopy (XPS) while the surface morphology, characterized by atomic force microscopy (AFM) presented the root mean square (RMS) surface roughness of 13.3 nm. Cross-section transmission electron microscopy (TEM) images of the device revealed Ti clusters dispersed in PTFE matrix with particle sizes varied between 10 nm and 30 nm.

  15. Semi-metallic, strong conductive polymer microfiber, method and fast response rate actuators and heating textiles

    KAUST Repository

    Zhou, Jian

    2016-06-09

    A method comprising: providing at least one first composition comprising at least one conjugated polymer and at least one solvent, wet spinning the at least one first composition to form at least one first fiber material, hot-drawing the at least one fiber to form at least one second fiber material. In lead embodiments, high-performance poly(3,4-ethylenedioxy- thiophene)/poly(styrenesulfonate) (PEDOT/PSS) conjugated polymer microfibers were fabricated via wet- spinning followed by hot-drawing. In these lead embodiments, due to the combined effects of the vertical hot-drawing process and doping/de-doping the microfibers with ethylene glycol (EG), a record electrical conductivity of 2804 S · cm-1 was achieved. This is believed to be a six-fold improvement over the best previously reported value for PEDOT/PSS fibers (467 S · cm-1) and a twofold improvement over the best values for conductive polymer films treated by EG de-doping (1418 S · cm-1). Moreover, these lead, highly conductive fibers experience a semiconductor-metal transition at 313 K. They also have superior mechanical properties with a Young\\'s modulus up to 8.3 GPa, a tensile strength reaching 409.8 MPa and a large elongation before failure (21%). The most conductive fiber also demonstrates an extraordinary electrical performance during stretching/unstretching: the conductivity increased by 25% before the fiber rupture point with a maximum strain up to 21%. Simple fabrication of the semi-metallic, strong and stretchable wet-spun PEDOT/PSS microfibers can make them available for conductive smart electronics. A dramatic improvement in electrical conductivity is needed to make conductive polymer fibers viable candidates in applications such as flexible electrodes, conductive textiles, and fast-response sensors and actuators.

  16. Tuning the magnetocaloric response of Er-based metallic glasses by varying structural order in disorder

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Qiang [School of Materials Science and Engineering, Tongji University, Shanghai 201804 (China); Tang, Meibo [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Shen, Jun, E-mail: junshen@tongji.edu.cn [School of Materials Science and Engineering, Tongji University, Shanghai 201804 (China)

    2016-03-01

    The effects of structural order on magnetocaloric response have been explored in Er{sub 60}Al{sub 16}Co{sub 20}Ni{sub 4} metallic glass (MG). Compared with the fully amorphous structure of the as-spun ribbon (cooling rate ∼10{sup 6} K/s), the rod sample fabricated with a lower cooling rate (∼10{sup 3} K/s) contains a few crystalline phases embedded in the amorphous matrix. Annealing the ribbon in the supercooled liquid region results in formation of a large amount of nanocrystalline phase. Both the as-spun ribbon and rod samples show a single spin-glass-like transition behavior, while the annealed sample exhibits double-freezing processes. It is found that the sparsely distributed micro-sized crystalline phases (content fraction of 13%) exert a slight effect on the magnetic entropy change (MEC). However, densely distributed nanocrystallization phase (∼50%) in amorphous matrix leads to an obvious reduction of the MEC and refrigerant capacity (RC). The exponent n of field dependence of MEC is found to related to exchange frustration, random anisotropy, and structure ordering degrees. - Highlights: • We determined the significant role of the size and distribution of the crystalline phases on the magnetic structure and magnetic performance of metallic glass composite. • It is found that the sparsely distributed micro-sized crystalline phases (content fraction of 13%) exert a slight effect on the MEC. • Densely distributed nanocrystalline phase (~50%) leads to an obvious reduction of the MEC.

  17. Fracture response of several metals to fast heating of samples by intensive X-ray radiation

    Science.gov (United States)

    Golubev, Vladimir

    2015-06-01

    Results on studying the fracture response of metals samples in the form of thin disks to fast heating by the intensive pulse of X-ray radiation of a complete spectrum are presented in the paper. The samples of such metals as iron, copper, AMg6 aluminum, VT14 titanium, molybdenum, tungsten, cadmium, lead and zinc were tested. The samples were fixed in the special cartridges that were placed at such distances from the X-ray irradiator where the energy fluxes were 1.38, 0.90 and 0.29 kJ/cm2. The irradiating X-ray pulse was about 2 ns in duration. After testing, the depth of material ablation from a sample front surface and the degree and character of its spall damage were determined. The method of metallographic analysis was used for these purposes. The spectrum data were used for the calculations of samples heating. Numerical calculations of thermomechanical and shock wave loading conditions were made with the use of the equation of state taking into account the process of evaporation. The calculated value of maximum negative pressure in the sample at the coordinate corresponding to the depth of ablation and formation of spallation zones or spall cracks was conventionally accepted as the material resistance to spall fracture in such conditions. The comparison of obtained results with the data on the fracture of examined materials in the conditions of fast heating by the X-ray pulse with a hard spectrum and by the high-current electron beam of an electron pulse generator was conducted.

  18. Fibroblast response to metallic debris in vitro. Enzyme induction cell proliferation, and toxicity.

    Science.gov (United States)

    Maloney, W J; Smith, R L; Castro, F; Schurman, D J

    1993-06-01

    Bovine synovial fibroblasts in primary monolayer culture were exposed to particulate metallic debris. The effects of the metallic particles on the synthesis and secretion of proteolytic enzymes and on cell proliferation and viability were examined. Uniform suspensions of titanium, titanium-aluminum, cobalt, and chromium particles, ranging in size from approximately 0.1 to ten micrometers (average, one to three micrometers), were prepared; the particle concentrations (the volume of particles divided by the total volume of the suspension) ranged from 0.0005 to 5 per cent. Aliquots of the particle suspensions were added to the synovial fibroblast cultures. The final particle concentrations in the media ranged from 0.0000083 to 0.83 per cent. After seventy-two hours of exposure, each medium was harvested and was assayed for proteolytic and collagenolytic activity and for hexosaminidase levels. Neutral metalloproteases, quantified by collagenolytic and caseinolytic (proteolytic) activity, represent enzymes, secreted by cells, that are capable of degrading extracellular matrix. Hexosaminidase is a marker for lysosomal enzyme activity that can include more than thirty enzymes, such as proteases, lipases, nucleases, and phosphatases. Cell proliferation was quantified by uptake of 3H-thymidine. Cell morphology was examined by scanning electron microscopy. Titanium, titanium-aluminum, and chromium significantly stimulated 3H-thymidine uptake at low particle concentrations (p < 0.01, p < 0.002, and p < 0.002, respectively). Exposure to cobalt, even at the lowest particle concentration, resulted in a significant decrease in thymidine uptake (p = 0.027). At the highest particle concentrations, all particles were toxic, as evidenced by the absence of thymidine uptake. At high particle concentrations, all of the metals caused a decrease in caseinolytic (proteolytic) and collagenolytic activity in the culture media. Titanium elevated the lysosomal enzyme marker, hexosaminidase

  19. Response of soil microflora to impact of heavy metals in zones of influence of railway transport

    Directory of Open Access Journals (Sweden)

    N. Bobryk

    2016-03-01

    microorganisms of ecological trophic groups and the content of acid-soluble lead forms at the levels of 0.72–1.72 maximum permissible concentrations. It was the nitrogen-fixing microorganisms and microscopic fungi that showed a fast response to heavy metals, which was an indication of their possible use as indicators of the ecological state of technogenically transformed soils.

  20. Impact of trace metal concentrations on coccolithophore growth and morphology: species-specific responses in past and present ocean

    Science.gov (United States)

    Faucher, Giulia; Hoffmann, Linn; Bach, Lennart Thomas; Bottini, Cinzia; Erba, Elisabetta; Riebesell, Ulf

    2017-04-01

    The Cretaceous witnessed intervals of profound perturbation named "Oceanic Anoxic Events (OAEs)" characterized by volcanic injection of large amounts of CO2, ocean anoxia, eutrophication, and introduction of biologically relevant metals. Some of these extreme events were characterized by size reduction and/or morphological changes of a number of nannofossil species. To detect the cause/s of such changes in the fossil record is challenging. Evidence of a correspondence between intervals of high trace metals concentrations and nannofossil dwarfism may be suggestive for a negative effect of these elements on nannoplankton biocalcification process. In order to verify the hypothesis that anomalously high quantities of essential and/or toxic metals were the cause of coccolith dwarfism, we explored the toxicities of a mixture of trace metals on four living coccolithophores species, namely Emiliania huxleyi, Gephyrocapsa oceanica, Pleurochrysis carterae and Coccolithus pelagicus. The trace metals tested were chosen based upon concentration peaks identified in the geological record and upon known trace metal interaction with living coccolithophores algae. Our results demonstrate a species-specific response to trace metal enrichment in living coccolithophores: E. huxleyi, G. oceanica and C. pelagicus showed a decrease in their growth rate with progressively and exponentially increased trace metal concentrations, while P. carterae is unresponsive to trace metal content. Furthermore, E. huxleyi, G. oceanica and C. pelagicus evidenced a decrease in the cell diameter. Smaller coccoliths were detected in E. huxleyi and C. pelagicus, while coccolith of G. oceanica showed a decrease in size only at the highest trace metal concentrations tested. P. carterae size was unresponsive for changing trace metal concentration. Our results on living coccolithophore algae, demonstrate that elevated trace metal concentrations not only affect growth but also coccolith size and/or weight and that

  1. Deduction and Analysis of the Interacting Stress Response Pathways of Metal/Radionuclide-reducing Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jizhong [University of Oklahoma; He, Zhili [University of Oklahoma

    2010-02-28

    Project Title: Deduction and Analysis of the Interacting Stress Response Pathways of Metal/Radionuclide-reducing Bacteria DOE Grant Number: DE-FG02-06ER64205 Principal Investigator: Jizhong (Joe) Zhou (University of Oklahoma) Key members: Zhili He, Aifen Zhou, Christopher Hemme, Joy Van Nostrand, Ye Deng, and Qichao Tu Collaborators: Terry Hazen, Judy Wall, Adam Arkin, Matthew Fields, Aindrila Mukhopadhyay, and David Stahl Summary Three major objectives have been conducted in the Zhou group at the University of Oklahoma (OU): (i) understanding of gene function, regulation, network and evolution of Desulfovibrio vugaris Hildenborough in response to environmental stresses, (ii) development of metagenomics technologies for microbial community analysis, and (iii) functional characterization of microbial communities with metagenomic approaches. In the past a few years, we characterized four CRP/FNR regulators, sequenced ancestor and evolved D. vulgaris strains, and functionally analyzed those mutated genes identified in salt-adapted strains. Also, a new version of GeoChip 4.0 has been developed, which also includes stress response genes (StressChip), and a random matrix theory-based conceptual framework for identifying functional molecular ecological networks has been developed with the high throughput functional gene array hybridization data as well as pyrosequencing data from 16S rRNA genes. In addition, GeoChip and sequencing technologies as well as network analysis approaches have been used to analyze microbial communities from different habitats. Those studies provide a comprehensive understanding of gene function, regulation, network, and evolution in D. vulgaris, and microbial community diversity, composition and structure as well as their linkages with environmental factors and ecosystem functioning, which has resulted in more than 60 publications.

  2. Magnetic response from a composite of metal-dielectric particles in the visible range: T-matrix simulation

    Directory of Open Access Journals (Sweden)

    O. Zhuromskyy

    2011-09-01

    Full Text Available The optical response of a particle composed of a dielectric core surrounded by a densely packed shell of small metal spheres is simulated with the superposition Tmatrix method for realistic material parameters. In order to compute the electric and magnetic particle polarizabilities a single expansion T-matrix is derived from a particle centered T-matrix. Finally the permeability of a medium comprising such particles is found to deviate considerable from unity resulting in a noticeable optical response.

  3. Instabilities in the optical response of a semiconductor quantum dot-metal nanoparticle heterodimer : self-oscillations and chaos

    NARCIS (Netherlands)

    Nugroho, Bintoro S.; Iskandar, Alexander A.; Malyshev, Victor A.; Knoester, Jasper

    We theoretically investigate the nonlinear optical response of a heterodimer comprising a semiconductor quantum dot strongly coupled to a metal nanoparticle. The quantum dot is considered as a three-level ladder system with ground, one-exciton, and bi-exction states. As compared to the case of a

  4. Defect-Induced Optoelectronic Response in Single-layer Group-VI Transition-Metal Dichalcogenides

    Science.gov (United States)

    Chow, Philippe K.

    The ever-evolving symbiosis between mankind and nanoelectronics-driven technology pushes the limits of its constituent materials, largely due to the dominance of undesirable hetero-interfacial physiochemical behavior at the few-nanometer length scale, which dominates over bulk material characteristics. Driven by such instabilities, research into two-dimensional (2D) van der Waals-layered materials (e.g. graphene, transition metal dichalcogenides (TMDCs), boron nitride), which have characteristically inert surface chemistry, has virtually exploded over the past few years. The discovery of an indirect- to direct-gap conversion in semiconducting group-VI TMDCs (e.g. MoS2) upon thinning to a single atomic layer provided the critical link between metallic and insulating 2D materials. While proof-of-concept demonstrations of single-layer TMDC-based devices for visible-range photodetection, light-emission and solar energy conversion have showed promising results, the exciting qualities are downplayed by poorly-understood defectinduced photocarrier traps, limiting the best-achieved external quantum efficiencies to approximately ~1%. This thesis explores the behavior of defects in atomically-thin TMDC layers in response to optical stimuli using a combination of steady-state photoluminescence, reflectance and Raman spectroscopy at room-temperature. By systematically varying the defect density using plasma-irradiation techniques, an unprecedented room-temperature defect-induced monolayer PL feature was discovered. High-resolution transmission electron microscopy correlated the defect-induced PL with plasma-generation of sulfur vacancy defects while reflectance measurements indicate defect-induced sub-bandgap light absorption. Excitation intensity-dependent PL measurements and exciton rate modeling further help elucidate the origin of the defect-induced PL response and highlights the role of non-radiative recombination on exciton conversion processes. The results in this

  5. Secure Supply Chains: Design Restrictions & Organizational Boundaries

    NARCIS (Netherlands)

    Ludema, M.W.

    2009-01-01

    An important issue in the design of secure supply chains is the understanding of the relation between supply chains and the organizational responsibility of specific parts of these supply chains. Organizational boundaries change over time by means of vertical and/or horizontal (des)-integration and

  6. Early transcriptomic response of Arabidopsis thaliana to polymetallic contamination: implications for the identification of potential biomarkers of metal exposure.

    Science.gov (United States)

    Gómez-Sagasti, María T; Barrutia, Oihana; Ribas, Griselda; Garbisu, Carlos; Becerril, José M

    2016-05-01

    Heavy metal contaminated sites are frequently characterized by the simultaneous presence of several heavy metals. However, many studies report metal-induced plant responses after long-term exposure to just one metal. By contrast, whole genome expression microarrays were employed here to investigate the early (3 h) transcriptional responses of Arabidopsis thaliana plants exposed to polymetallic treatment (Pb, Hg, Cu, Cd, Co, Ni, Zn, and Mn) at low (L) and high (H) concentrations. After 3 h of exposure to polymetallic treatment, a total of 1315 noticeably (≥2-fold) and significantly (P < 0.05) differentially expressed genes were identified: 656 and 351 upregulated and 314 and 200 downregulated genes in L and H treatments, respectively. Functional analysis revealed that many genes involved in oxidative stress and perception/signalling/regulation systems were activated. Genes encoding proteins involved in hormone regulation (jasmonic acid, abscisic acid, ethylene, and auxins), glucosinolate metabolism and sulphur and nitrogen transport were also modulated. RT-qPCR analysis of four downregulated (AOP2, SAUR16, BBX31, and MTPC3) and upregulated genes (ASN1, DIN2, BT2, and EXL5), markedly responsive to both L and H treatments, validated our microarray data and suggested the potential of some of these genes (AOP2, SAUR16, ASN1, and DIN2) as early biomarkers of metal exposure. Relevant changes in gene expression occur as early as 3 h after exposure to polymetallic treatment. Four genes deserve further studies as novel putative biomarkers of early metal exposure and also owing to their potential implications in stress-related mechanisms: sulphur balance (AOP2), phytohormone regulation of plant growth and development (SAUR16), ammonium detoxification (ASN1) and senescence (DIN2).

  7. Correlation of Bandgap Reduction with Inversion Response in (Si)GeSn/High-k/Metal Stacks.

    Science.gov (United States)

    Schulte-Braucks, C; Narimani, K; Glass, S; von den Driesch, N; Hartmann, J M; Ikonic, Z; Afanas'ev, V V; Zhao, Q T; Mantl, S; Buca, D

    2017-03-15

    The bandgap tunability of (Si)GeSn group IV semiconductors opens a new era in Si-technology. Depending on the Si/Sn contents, direct and indirect bandgaps in the range of 0.4-0.8 eV can be obtained, offering a broad spectrum of both photonic and low power electronic applications. In this work, we systematically studied capacitance-voltage characteristics of high-k/metal gate stacks formed on GeSn and SiGeSn alloys with Sn-contents ranging from 0 to 14 at. % and Si-contents from 0 to 10 at. % particularly focusing on the minority carrier inversion response. A clear correlation between the Sn-induced shrinkage of the bandgap energy and enhanced minority carrier response was confirmed using temperature and frequency dependent capacitance voltage-measurements, in good agreement with k.p theory predictions and photoluminescence measurements of the analyzed epilayers as reported earlier. The enhanced minority generation rate for higher Sn-contents can be firmly linked to the bandgap reduction in the GeSn epilayer without significant influence of substrate/interface effects. It thus offers a unique possibility to analyze intrinsic defects in (Si)GeSn epilayers. The extracted dominant defect level for minority carrier inversion lies approximately 0.4 eV above the valence band edge in the studied Sn-content range (0-12.5 at. %). This finding is of critical importance since it shows that the presence of Sn by itself does not impair the minority carrier lifetime. Therefore, the continuous improvement of (Si)GeSn material quality should yield longer nonradiative recombination times which are required for the fabrication of efficient light detectors and to obtain room temperature lasing action.

  8. Crystal Dynamics in Multi-stimuli-Responsive Entangled Metal-Organic Frameworks.

    Science.gov (United States)

    Kanoo, Prakash; Haldar, Ritesh; Reddy, Sandeep K; Hazra, Arpan; Bonakala, Satyanarayana; Matsuda, Ryotaro; Kitagawa, Susumu; Balasubramanian, Sundaram; Maji, Tapas Kumar

    2016-10-24

    An understanding of solid-state crystal dynamics or flexibility in metal-organic frameworks (MOFs) showing multiple structural changes is highly demanding for the design of materials with potential applications in sensing and recognition. However, entangled MOFs showing such flexible behavior pose a great challenge in terms of extracting information on their dynamics because of their poor single-crystallinity. In this article, detailed experimental studies on a twofold entangled MOF (f-MOF-1) are reported, which unveil its structural response toward external stimuli such as temperature, pressure, and guest molecules. The crystallographic study shows multiple structural changes in f-MOF-1, by which the 3 D net deforms and slides upon guest removal. Two distinct desolvated phases, that is, f-MOF-1 a and f-MOF-1 b, could be isolated; the former is a metastable one and transformable to the latter phase upon heating. The two phases show different gated CO2 adsorption profiles. DFT-based calculations provide an insight into the selective and gated adsorption behavior with CO2 of f-MOF-1 b. The gate-opening threshold pressure of CO2 adsorption can be tuned strategically by changing the chemical functionality of the linker from ethanylene (-CH2 -CH2 -) in f-MOF-1 to an azo (-N=N-) functionality in an analogous MOF, f-MOF-2. The modulation of functionality has an indirect influence on the gate-opening pressure owing to the difference in inter-net interaction. The framework of f-MOF-1 is highly responsive toward CO2 gas molecules, and these results are supported by DFT calculations. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Ac-conductivity and dielectric response of new zinc-phosphate glass/metal composites

    Science.gov (United States)

    Maaroufi, A.; Oabi, O.; Lucas, B.

    2016-07-01

    The ac-conductivity and dielectric response of new composites based on zinc-phosphate glass with composition 45 mol%ZnO-55 mol%P2O5, filled with metallic powder of nickel (ZP/Ni) were investigated by impedance spectroscopy in the frequency range from 100 Hz to 1 MHz at room temperature. A high percolating jump of seven times has been observed in the conductivity behavior from low volume fraction of filler to the higher fractions, indicating an insulator - semiconductor phase transition. The measured conductivity at higher filler volume fraction is about 10-1 S/cm and is frequency independent, while, the obtained conductivity for low filler volume fraction is around 10-8 S/cm and is frequency dependent. Moreover, the elaborated composites are characterized by high dielectric constants in the range of 105 for conductive composites at low frequencies (100 Hz). In addition, the distribution of the relaxation processes was also evaluated. The Debye, Cole-Cole, Davidson-Cole and Havriliak-Negami models in electric modulus formalism were used to model the observed relaxation phenomena in ZP/Ni composites. The observed relaxation phenomena are fairly simulated by Davidson-Cole model, and an account of the interpretation of results is given.

  10. Revisiting the extended producer responsibility program for metal packaging in South Korea.

    Science.gov (United States)

    Kim, Soyoung; Mori, Akihisa

    2015-05-01

    Recently, developed and emerging countries have increasingly adopted the principle of extended producer responsibility (EPR) to reduce waste. In 2003, South Korea replaced the waste deposit recycling (WDR) program with the EPR program. Previous comparative analyses between the WDR and EPR programs have been qualitative evaluations and have not yet quantitatively shown whether the change has increased benefits. The aim of this paper is to explore which program brings larger net benefits. Because of limited data availability, here we focus on metal packaging exclusively. We find that the recycling rate dropped from 59% in 2000 to 40% in 2011 and recycling volume dropped accordingly. Cost-benefit incidence analysis shows that net social benefits decreased by 2.8 billion won (2.5 million US dollars), while the net benefits to producers increased by 1.9 billion won (1.7 million US dollars) under the EPR program compared with the WDR program. The government of South Korea should set an ambitious recycling target and narrow the scope of the exemption from the mandatory recycling requirement.

  11. THERMO-ELASTIC-PLASTIC RESPONSE AND OPTIMUM DESIGN OF CERAMIC-METAL FGMS-CYCLIC THERML LOADING PROBLEM

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The materials are made with a graded composition and microstructure in the thick ness direction from the ceramic side to the metal side. The cyclic thermal loadi ng and hig h temperasure gradient environment are simulated by heating the ceramic surface w ith a cyclic heat flux input and cooling the metal surface with a flowing liquid niterogen. The thermal and thermo-elastic-plastic response of the materials i s calculated using the isotropic hardening model and kinetic hardening model. Emp hasis is placed on the response analysis under the different graded compositiona l distributions. Through the response analysis, the optimum design process of th e graded composition under the dynamic case is established, which is based on a unified viewpoint of the heat insulation property, thermal stress relaxation pro perty and stress history feature.

  12. Heavy metal mediated innate immune responses of the Indian green frog, Euphlyctis hexadactylus (Anura: Ranidae): Cellular profiles and associated Th1 skewed cytokine response.

    Science.gov (United States)

    Jayawardena, Uthpala A; Ratnasooriya, Wanigasekara D; Wickramasinghe, Deepthi D; Udagama, Preethi V

    2016-10-01

    Immune cell and cytokine profiles in relation to metal exposure though much studied in mammals has not been adequately investigated in amphibians, due mainly to lack of suitable reagents for cytokine profiling in non-model species. However, interspecies cross reactivity of cytokines permitted us to assay levels of IFNγ, TNFα, IL6 and IL10in a common anuran, the Indian green frog (Euphlyctis hexadactylus), exposed to heavy metals (Cd, Cr, Cu, Zn and Pb, at ~5ppm each) under field and laboratory settings in Sri Lanka. Enumeration of immune cells in blood and melanomacrophages in the liver, assay of serum and hepatic cytokines, and Th1/Th2 cytokine polarisation were investigated. Immune cell counts indicated overall immunosuppression with decreasing total WBC and splenocyte counts while neutrophil/lymphocyte ratio increased with metal exposure, indicating metal mediated stress. Serum IL6 levels of metal exposed frogs reported the highest (~9360pg/mL) of all cytokines tested. Significantly elevated IFNγ production (Pfrogs. Th1/Th2 cytokine ratio in both serum and liver tissue homogenates was Th1 skewed due to significantly higher production of pro-inflammatory cytokines, IFNγ in serum and TNFα in the liver (P<0.01).Metal mediated aggregations of melanomacrophages in the liver were positively and significantly (P<0.05) correlated with the hepatic expression of TNFα, IL6 and IL10 activity. Overall, Th1 skewed response may well be due to oxidative stress mediated nuclear factor κ-light chain enhancer of activated B cells (NFκB) which enhances the transcription of pro-inflammatory cytokines. Xenobiotic stress has recently imposed an unprecedented level of threat to wildlife, particularly to sensitive species such as amphibians. Therefore, understanding the interactions between physiological stress and related immune responses is fundamental to conserve these environmental sentinels in the face of emerging eco-challenges.

  13. Assessing colloid-bound metal export in response to short term changes in runoff from a forested catchment

    Science.gov (United States)

    Neubauer, E.; Kammer, F. v. d.; Knorr, K.-H.; Pfeiffer, S.; Reichert, M.; Hofmann, T.

    2012-04-01

    Soils can act as a source of metals and natural organic matter (NOM) in runoff from catchments. Amounts and intensity of rainfall may influence NOM export from catchments. The presence of NOM and other colloids in water may not only enhance metal export, but also significantly change metal speciation. In this study, we investigated the response of metal-colloid associations to short-term discharge variations in the runoff from a small forested catchment (Lehstenbach, Bavaria, Germany). Here, the discharge from the catchment outlet responds within hours to rain events. Near-surface flow in organic-rich layers and peat soils has been identified to increase dissolved organic carbon (DOC) concentrations during stormwater runoff. Flow Field-Flow Fractionation coupled to ICP-MS (FlowFFF-ICPMS) is a high-resolution size separation technique which was used for the detection and quantification of colloids and associated metals. Colloid-associated metals, dissolved metals and metals associated with low-molecular weight organic ligands were also separated by filtration (0.2 µm) and ultrafiltration (1000 g/mol MWCO). During baseflow DOC concentration was complexation during all hydrological conditions. A clear temporal pattern in the association with the NOM was observed for most of the metals under study: During baseflow, 70-100% (Fe), 90% (Al), 60-100% (REE) and 80-85% (U) were associated with the NOM. During stormwater runoff, the dissolved species concentration and those associated with small organic ligands (<1000 g/mol) increased. The pH drop during the stormwater runoff (pH <4) is most likely the main factor for weaker metal-NOM binding. However, only 25 to 50% of the arsenic was associated with NOM, but no relation to discharge, or pH was exhibited. The results show that fluxes of most trace metals from the catchment are governed by NOM-colloids, even though substantial concentrations are dissolved or associated to low-molecular weight organic substances during

  14. Adhesion analysis between metal supplies and composites materials reinforce with glass fiber; Analise de adesao antre materiais metalicos e materiais compositos reforcados com fibra e vidro

    Energy Technology Data Exchange (ETDEWEB)

    Oushiro, Karol B.; Costa, Anahi P. da; Botelho, Edson C. [UNESP, Guaratingueta, SP (Brazil). Faculdade de Engenharia. Dept. de Materiais e Tecnologia], e-mail: kaoushiro@hotmail.com; Costa, Michelle L. [UNESP, Guaratingueta, SP (Brazil). Faculdade de Engenharia. Dept. de Materiais e Tecnologia; Instituto de Aeronautica e Espaco (AMR/IAE/DCTA), Sao Jose dos Campos, SP (Brazil). Div. de Materiais

    2011-07-01

    The appearance of defects, mainly thinning caused by corrosion, is unavoidable in pipeline transport of fluids. Many repair techniques have been developed, among them, has been highlighting the pipeline repair with composite that is to involve the passage of the corroded pipeline with composite material. The study of these techniques is of great interest for the branch industry, since the efficiency of repair will depend on good adhesion between the repair composite and steel pipe. In this work, the bond strength between fiber glass/epoxy composite bonded to a steel tubing used in petrochemical plants was evaluated by mechanical testing of lap shear (ASTM D1002). These samples were conditioned using 2000 thermal shock cycles, and the mechanical results of the conditioned and non-conditioned samples were compared. With this, we observed that the polymer composites can be successfully used for repair of metallic pipes with petrochemical application, because when exposed to sudden temperature changes their mechanical properties (shear) remained practically unchanged. (author)

  15. Metabolic and clinical response to Escherichia coli lipopolysaccharide in layer pullets of different genetic backgrounds supplied with graded dietary L-arginine.

    Science.gov (United States)

    Lieboldt, M A; Frahm, J; Halle, I; Görs, S; Schrader, L; Weigend, S; Preisinger, R; Metges, C C; Breves, G; Dänicke, S

    2016-03-01

    L-arginine (Arg) is an essential amino acid in birds that plays a decisive role in avian protein synthesis and immune response. Effects of graded dietary Arg supply on metabolic and clinical response to Escherichia coli lipopolysaccharide (LPS) were studied over 48 hours after a single intramuscular LPS injection in 18-week-old genetically diverse purebred pullets. LPS induced a genotype-specific fever response within 4 hours post injectionem. Whereas brown genotypes showed an initial hypothermia followed by longer-lasting moderate hyperthermia, white genotypes exhibited a biphasic hyperthermia without initial hypothermia. Furthermore, within 2 hours after LPS injection, sickness behavior characterized by lethargy, anorexia, intensified respiration, and ruffled feathers appeared, persisted for 3 to 5 hours and recovered 12 hours post injectionem. The varying grades of Arg did not alter the examined traits named above, whereas insufficient Arg reduced body growth and increased relative weights of liver and pancreas significantly. At 48 hours post injectionem, increased relative weights of liver and spleen were also found in LPS treated pullets, whereas LPS decreased those of pancreas, bursa, thymus, and cecal tonsils. Moreover, LPS lowered the sum of plasma amino acids and decreased plasma concentrations of Arg, citrulline, glutamate, methionine, ornithine, phenylalanine, proline, tryptophan, and tyrosine, and increased those of aspartate, glutamine, lysine, 1- and 3-methyl-histidine. Elevating concentrations of dietary Arg led to increasing plasma concentrations of Arg, citrulline, ornithine, and 3-methyl-histidine subsequently. As quantitative expression of LPS-induced anorexia, proteolysis, and the following changes in plasma amino acids, pullets showed a significant decrease of feed and nitrogen intake and catabolic metabolism characterized by negative nitrogen balance and body weight loss in the first 24 hours post injectionem. Pullets recovered from the

  16. Beneficial role of plant growth promoting bacteria and arbuscular mycorrhizal fungi on plant responses to heavy metal stress.

    Science.gov (United States)

    Gamalero, Elisa; Lingua, Guido; Berta, Graziella; Glick, Bernard R

    2009-05-01

    Heavy metal pollution is a major worldwide environmental concern that has recently motivated researchers to develop a variety of novel approaches towards its cleanup. As an alternative to traditional physical and chemical methods of environmental cleanup, scientists have developed phytoremediation approaches that include the use of plants to remove or render harmless a range of compounds. Both plant growth promoting bacteria (PGPB) and arbuscular mycorrhizal fungi (AMF) can be used to facilitate the process of phytoremediation and the growth of plants in metal-contaminated soils. This review focuses on the recent literature dealing with the effects of plant growth-promoting bacteria and AM fungi on the response of plants to heavy metal stress and points the way to strategies that may facilitate the practical realization of this technology.

  17. Virtual Institute of Microbial Stress and Survival: Deduction of Stress Response Pathways in Metal and Radionuclide Reducing Microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    None

    2004-04-17

    The projects application goals are to: (1) To understand bacterial stress-response to the unique stressors in metal/radionuclide contamination sites; (2) To turn this understanding into a quantitative, data-driven model for exploring policies for natural and biostimulatory bioremediation; (3) To implement proposed policies in the field and compare results to model predictions; and (4) Close the experimental/computation cycle by using discrepancies between models and predictions to drive new measurements and construction of new models. The projects science goals are to: (1) Compare physiological and molecular response of three target microorganisms to environmental perturbation; (2) Deduce the underlying regulatory pathways that control these responses through analysis of phenotype, functional genomic, and molecular interaction data; (3) Use differences in the cellular responses among the target organisms to understand niche specific adaptations of the stress and metal reduction pathways; (4) From this analysis derive an understanding of the mechanisms of pathway evolution in the environment; and (5) Ultimately, derive dynamical models for the control of these pathways to predict how natural stimulation can optimize growth and metal reduction efficiency at field sites.

  18. A combined NDE/FEA approach to evaluate the structural response of a metal foam

    Science.gov (United States)

    Ghosn, Louis J.; Abdul-Aziz, Ali; Raj, Sai V.; Rauser, Richard W.

    2007-04-01

    Metal foams are expected to find use in structural applications where weight is of particular concern, such as space vehicles, rotorcraft blades, car bodies or portable electronic devices. The obvious structural application of metal foam is for light weight sandwich panels, made up of thin solid face sheets and a metallic foam core. The stiffness of the sandwich structure is increased by separating the two face sheets by a light weight metal foam core. The resulting high-stiffness structure is lighter than that constructed only out of the solid metal material. Since the face sheets carry the applied in-plane and bending loads, the sandwich architecture is a viable engineering concept. However, the metal foam core must resist transverse shear loads and compressive loads while remaining integral with the face sheets. Challenges relating to the fabrication and testing of these metal foam panels remain due to some mechanical properties falling short of their theoretical potential. Theoretical mechanical properties are based on an idealized foam microstructure and assumed cell geometry. But the actual testing is performed on as fabricated foam microstructure. Hence in this study, a detailed three dimensional foam structure is generated using series of 2D Computer Tomography (CT) scans. The series of the 2D images are assembled to construct a high precision solid model capturing all the fine details within the metal foam as detected by the CT scanning technique. Moreover, a finite element analysis is then performed on as fabricated metal foam microstructures, to calculate the foam mechanical properties with the idealized theory. The metal foam material is an aerospace grade precipitation hardened 17-4 PH stainless steel with high strength and high toughness. Tensile and compressive mechanical properties are deduced from the FEA model and compared with the theoretical values for three different foam densities. The combined NDE/FEA provided insight in the variability of

  19. Antioxidative responses of the tissues of two wild populations of Pelophylax kl. esculentus frogs to heavy metal pollution.

    Science.gov (United States)

    Prokić, Marko D; Borković-Mitić, Slavica S; Krizmanić, Imre I; Mutić, Jelena J; Vukojević, Vesna; Nasia, Mohammed; Gavrić, Jelena P; Despotović, Svetlana G; Gavrilović, Branka R; Radovanović, Tijana B; Pavlović, Slađan Z; Saičić, Zorica S

    2016-06-01

    on the results in this study, we concluded that increased concentrations of heavy metals in frog tissues can alter the AOS, which leads to higher concentrations of GSH and SH groups and lower activities of antioxidative enzymes. The response of the AOS to metal pollutants allowed us to make a distinction between different frog tissues, and to conclude that the liver and skin are more suitable for assessing metal-induced oxidative stress in frogs than muscle.

  20. Assessment of antioxidant responses and trace metal accumulation by digestive gland of ribbed mussel Aulacomya atra atra from Northern Patagonia.

    Science.gov (United States)

    Giarratano, Erica; Gil, Mónica N; Malanga, Gabriela

    2013-06-01

    Seasonal and spatial variability of trace metal concentrations and of a battery of antioxidant parameters were evaluated in digestive gland of the ribbed mussel Aulacomya atra atra. Fe, Al and Cu accumulated in tissue exhibited maximum values in winter, coinciding partially with the highest labile concentrations of Fe and Cu in sediment. Metals, as other pollutants, are known to influence the oxidative status of organisms and antioxidant enzymes have been often proposed as biomarkers of contaminant effects. Seasonal variations of trace metals did not appear to influence those of biochemical parameters, which generally showed an opposite trend with higher enzymatic activities in summer when trace metal concentrations were lower. Organisms from Punta Cuevas (control site) showed higher induction of reactive oxygen species production than those from both considered impacted sites, suggesting the possibility of some biochemical adaptation in organisms or a higher modulation of environmental and physiological factors on antioxidant responses than levels of trace metals. This study, which is the first in the area in this matter, showed that seasonal variations of potential biomarkers should be incorporated into interpretation of long-term biomonitoring studies in this marine coastal ecosystem. Copyright © 2013 Elsevier Inc. All rights reserved.

  1. Suspended sediment transport response to upstream wash-load supply in the sand-bed reach of the Upper Yellow River, China

    Science.gov (United States)

    Ta, Wanquan; Wang, Haibin; Jia, Xiaopeng

    2015-09-01

    Wash load is a major component of suspended sediment transport in the sand-bed reach of the Upper Yellow River, China. This wash load sediment originates from the Loess region, with the high runoff mainly originating from the rock mountains of its upstream basin. These characteristics result in a mismatch between water and sediment sources and a low probability of high runoffs meeting high suspended sediment concentration (SSC) flows. As a result, higher runoff with lower SSC levels (HR-LS) and lower runoff with higher SSC values (HS) occur, whose SSCs do not follow the typical power form for flow discharges, Ci = αQβ, where Ci and Q are SSC and flow discharge, respectively. Here, we modify the traditional power form with an upstream wash-load supply function C1-β to satisfy the relation between the water and wash load sediment concentrations in water-sediment mismatched cases, Ci = αQβC1-β, where C is an input flow's SSC. Using the daily flow discharges and SSCs of nine typical HR-LS flows and 18 HS flows in our study reach from 1960 to 2012, we find that β changes in response to input flow conditions and downstream transport distances. When the downstream transport distance is between 360 and 663.5 km, β varies between 0.3 and 0.6 in a HS input flow condition, while in the HR-LS input flow case, β tends to be greater than 0.6 (between 0.74 and 0.65). The entrainment rate of an HR-LS flow and the deposition rate of an HS flow appear to be asymmetrically balanced, establishing a primary mechanism for channel aggradation and upward fining of floodplains in our study reach.

  2. Functional gene pyrosequencing and network analysis: an approach to examine the response of denitrifying bacteria to increased nitrogen supply in salt marsh sediments

    Directory of Open Access Journals (Sweden)

    Jennifer L. Bowen

    2013-11-01

    Full Text Available Functional gene pyrosequencing is emerging as a useful tool to examine the diversity and abundance of microbes that facilitate key biogeochemical processes. One such process, denitrification, is of particular importance because it converts fixed nitrate (NO3- to N2 gas, which returns to the atmosphere. In N limited salt marshes, removal of NO3- prior to entering adjacent waters helps prevent eutrophication. Understanding the dynamics of salt marsh microbial denitrification is thus imperative for the maintenance of healthy coastal ecosystems. We used pyrosequencing of the nirS gene to examine the denitrifying community response to fertilization in experimentally enriched marsh plots. A key challenge in the analysis of sequence data derived from pyrosequencing is understanding whether small differences in gene sequences are ecologically meaningful. We apply a novel approach from information theory that determined that the optimal similarity level for clustering DNA sequences into OTUs, while still capturing the ecological complexity of the system, was 88% similarity. With this clustering, phylogenetic analysis yielded 6 dominant clades of denitrifiers, the largest of which, accounting for more than half of all the sequences collected, had no close cultured representatives. Of the 638 OTUs identified, only 11 were present in all plots and no single OTU was dominant. We did, however, find a large number of specialist OTUs that were present only in a single plot. The high degree of endemic OTUs, while accounting for a large proportion of the nirS diversity in the plots, were found in lower abundance than the generalist taxa. The proportion of specialist taxa increased with increasing supply of nutrients, suggesting that addition of fertilizer may create conditions that expand the niche space for denitrifying organisms and may enhance the genetic capacity for denitrification.

  3. Responsivity drop due to conductance modulation in GaN metal-semiconductor-metal Schottky based UV photodetectors on Si(111)

    Science.gov (United States)

    Ravikiran, L.; Radhakrishnan, K.; Dharmarasu, N.; Agrawal, M.; Wang, Zilong; Bruno, Annalisa; Soci, Cesare; Lihuang, Tng; Kian Siong, Ang

    2016-09-01

    GaN Schottky metal-semiconductor-metal (MSM) UV photodetectors were fabricated on a 600 nm thick GaN layer, grown on 100 mm Si (111) substrate using an ammonia-MBE growth technique. In this report, the effect of device dimensions, applied bias and input power on the linearity of the GaN Schottky-based MSM photodetectors on Si substrate were investigated. Devices with larger interdigitated spacing, ‘S’ of 9.0 μm between the fingers resulted in good linearity and flat responsivity characteristics as a function of input power with an external quantum efficiency (EQE) of ˜33% at an applied bias of 15 V and an input power of 0.8 W m-2. With the decrease of ‘S’ to 3.0 μm, the EQE was found to increase to ˜97%. However, devices showed non linearity and drop in responsivity from flatness at higher input power. Moreover, the position of dropping from flatter responsivity was found to shift to lower powers with increased bias. The drop in the responsivity was attributed to the modulation of conductance in the MSM due to the trapping of electrons at the dislocations, resulting in the formation of depletion regions around them. In devices with lower ‘S’, both the image force reduction and the enhanced collection efficiency increased the photocurrent as well as the charging of the dislocations. This resulted in the increased depletion regions around the dislocations leading to the modulation of conductance and non-linearity.

  4. Changes in plasma and erythrocyte omega-6 and omega-3 fatty acids in response to intravenous supply of omega-3 fatty acids in patients with hepatic colorectal metastases

    OpenAIRE

    Al-Taan, Omer; Stephenson, James A.; Spencer, Laura; Pollard, Cristina; West, Annette L; Philip C. Calder; Metcalfe, Matthew; Dennison, Ashley R.

    2013-01-01

    Background Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are functionally the most important omega-3 polyunsaturated fatty acids (PUFAs). Oral supply of these fatty acids increases their levels in plasma and cell membranes, often at the expense of the omega-6 PUFAs arachidonic acid (ARA) and linoleic acid. This results in an altered pattern of lipid mediator production to one which is less pro-inflammatory. We investigated whether short term intravenous supply of omega-3 PUFAs co...

  5. Assessment of Non-Revenue Water Situation in Mandalay City: Response to the Management of Sustainable Water Supply System in Mandalay City

    OpenAIRE

    Ser Moe Yi; Kampanad Bhaktikul; Kobkaew Manomaipiboon; Thongplew Kongjun

    2017-01-01

    Mandalay city is experiencing inefficient use of groundwater resources and inadequate water supply system to residents. The study focused on the issue of non-revenue water (NRW) and stakeholders’ perception on its management in order to design the remediation measures for the water lost controls and the sustainable water supply system. A total of 134 samples of water employees, and 383 households were assessed through structured questionnaires. It has been found that more than 50% of the wate...

  6. The analysis of the management of corporate social responsibility in food supply chain%食品供应链企业社会责任管理分析

    Institute of Scientific and Technical Information of China (English)

    姜启军

    2012-01-01

    This paper analyzes the management of corporate social responsibility(CSR) from the perspective of the food supply chain.We first analyzed the features about CSR of food enterprise and connotation of food supply chain CSR.In the performance of CSR of the food supply chain,the CSR benefit and the risk sharing,but food supply chain CSR is not clear definition,the enterprises in food supply chain lack thinking CSR at the whole supply chain level,the enterprise status and CSR level are different in food supply chain.In the food supply chain environment,we should be proactive to manage food supply chain CSR,take cooperative,symbiosis strategy,risk avoidance strategy,the core enterprise driving strategies and information sharing strategies.All members of the food supply chain should be active to fulfill their supply chain CSR standard,and constantly improve the whole supply chain CSR level.The leading enterprise in food supply chain should plan the sustainable development strategy about CSR for the whole industry chain,and constantly regulate,guide and help the food supply chain members to perform CSR,and drive supply chain CSR management and development.%从食品供应链的角度探讨企业社会责任管理问题。分析了食品企业社会责任的特征和食品供应链企业社会责任的内涵。在食品供应链社会责任表现上,供应链社会责任利益共享,风险共担,但食品供应链企业社会责任界定不清,各主体缺少从整体角度考虑供应链企业社会责任问题,供应链下企业的地位和社会责任水平不同。在食品供应链环境下,企业应积极主动管理供应链社会责任,采取协同、共生的策略、风险规避策略、核心企业驱动策略和信息共享策略。食品供应链的所有成员应积极主动履行各自的供应链企业社会责任规范,不断提高整条供应链的企业社会责任水平。食品供应链中的主导企业应该从全产业链可持续发展的战略

  7. Growth and characterization of rutile TiO2 nanorods on various substrates with fabricated fast-response metal-semiconductor-metal UV detector based on Si substrate

    Science.gov (United States)

    Selman, Abbas M.; Hassan, Z.

    2015-07-01

    Rutile-phase titanium dioxide nanorods (NRs) were synthesized successfully on p-type silicon (Si) (1 1 1), c-plane sapphire (Al2O3), glass coated with fluorine-doped tin oxide (FTO), glass, and quartz substrates via chemical bath deposition method. All substrates were seeded with a TiO2 seed layer synthesized with a radio frequency reactive magnetron sputtering system prior to NRs growth. The effect of substrate type on structural, morphological, and optical properties of rutile TiO2 NRs was studied. X-ray diffraction, Raman spectroscopy, and field-emission scanning electron microscopy analyses showed the tetragonal rutile structure of the synthesized TiO2 NRs. Optical properties were examined with photoluminescence (PL) spectroscopy of the grown rutile NRs on all substrates, with the spectra exhibiting one strong ultraviolet emission peak intensity compared with broad visible peak. The optimal sample of rutile NRs was grown on Si substrate. Thus, a fast-response metal-semiconductor-metal ultraviolet (UV) detector was fabricated. Upon exposure to 365 nm light (2.3 mW/cm2) at 5 V bias, the device displays 2.62 × 10-5 A photocurrent, and the response and recovery times are calculated as 18.5 and 19.1 ms, respectively. These results demonstrate that the fabricated high-quality photodiode is a promising candidate as a low-cost UV photodetector for commercially integrated photoelectronic applications.

  8. Ultralong Persistent Room Temperature Phosphorescence of Metal Coordination Polymers Exhibiting Reversible pH-Responsive Emission.

    Science.gov (United States)

    Yang, Yongsheng; Wang, Ke-Zhi; Yan, Dongpeng

    2016-06-22

    Ultra-long-persistent room temperature phosphorescence (RTP) materials have attracted much attention and present various applications in illumination, displays, and the bioimaging field; however, the persistent RTP is generally from the inorganic phosphor materials to date. Herein, we show that the metal coordination polymers (CPs) could be new types of emerging long-lived RTP materials for potential sensor applications. First, two kinds of Cd-based CPs, Cd(m-BDC)(H2O) (1) and Cd(m-BDC)(BIM) (2) (m-BDC = 1,3-benzenedicarboxylic acid; BIM = benzimidazole), were obtained through a hydrothermal process, and the samples were found to exhibit two-dimensional layered structures, which are stabilized by interlayer C-H···π interaction and π···π interaction, respectively. The CPs show unexpected second-time-scale ultra-long-persistent RTP after the removal of UV excitation, and this persistent emission can be detected easily on a time scale of 0-10 s. The CPs also feature a tunable luminescence decay lifetime by adjusting their coordination situation and packing fashion of ligands. Theoretical calculation further indicates that the introduction of the second ligand could highly influence the electronic structure and intermolecular electron transfer toward tailoring the RTP of the CP materials. Moreover, CP 2 exhibits well-defined pH- and temperature-dependent phosphorescence responses. Therefore, this work provides a facile way to develop new type of CPs with steady-state and dynamic tuning of the RTP properties from both experimental and theoretical perspectives, which have potential applications in the areas of displays, pH/temperature sensors, and phosphorescence logic gates. On account of suitable incorporation of inorganic and organic building blocks, it can be expected that the ultra-long-persistent RTP CPs can be extended to other similar systems due to the highly tunable structures and facile synthesis routes.

  9. Metal accumulation and oxidative stress responses in, cultured and wild, white seabream from Northwest Atlantic.

    Science.gov (United States)

    Ferreira, Marta; Caetano, Miguel; Costa, Joana; Pousão-Ferreira, Pedro; Vale, Carlos; Reis-Henriques, Maria Armanda

    2008-12-15

    Metals are environmentally ubiquitous and can be found at high concentrations in seawater and subsequently in marine organisms. Metals with high redox potential can trigger oxidative stress mechanisms with damaging effects in biological tissues. In aquatic species, oxidative stress has been evaluated by assessing antioxidant enzymes activities and oxidative damages in tissues. The purpose of this study was to evaluate oxidative stress biomarkers and metal residues in white seabream (Diplodus sargus), a species entering aquaculture production in Portugal. Metal residues (Cu, Cd, As and Pb), in liver and muscle, as well as oxidative stress biomarkers were assessed at different stages in the life cycle of white seabream under culture conditions and in wild specimens, of a marketable size. Metal concentrations in tissues were low, and below the established limits. However, wild white seabream showed higher accumulation than cultured ones. Antioxidant enzymes, namely catalase (CAT) and superoxide dismutase (SOD), were correlated with metal accumulation. Oxidative damages to tissues were low, with wild white seabream showing lower levels than cultured fish. This study showed that white seabream has a good antioxidant defense system, capable of reducing oxidative damages in tissues resulting from the presence of metals.

  10. AtNRAMP3, a multispecific vacuolar metal transporter involved in plant responses to iron deficiency.

    Science.gov (United States)

    Thomine, Sébastien; Lelièvre, Françoise; Debarbieux, Elise; Schroeder, Julian I; Barbier-Brygoo, Hélène

    2003-06-01

    Metal homeostasis is critical for the survival of living organisms, and metal transporters play central roles in maintaining metal homeostasis in the living cells. We have investigated the function of a metal transporter of the NRAMP family, AtNRAMP3, in Arabidopsis thaliana. A previous study showed that AtNRAMP3 expression is upregulated by iron (Fe) starvation and that AtNRAMP3 protein can transport Fe. In the present study, we used AtNRAMP3 promoter beta-glucoronidase (GUS) fusions to show that AtNRAMP3 is expressed in the vascular bundles of roots, stems, and leaves under Fe-sufficient conditions. This suggests a function in long-distance metal transport within the plant. Under Fe-starvation conditions, the GUS activity driven by the AtNRAMP3 promoter is upregulated without any change in the expression pattern. We analyze the impact of AtNRAMP3 disruption and overexpression on metal accumulation in plants. Under Fe-sufficient conditions, AtNRAMP3 overexpression or disruption does not lead to any change in the plant metal content. Upon Fe starvation, AtNRAMP3 disruption leads to increased accumulation of manganese (Mn) and zinc (Zn) in the roots, whereas AtNRAMP3 overexpression downregulates Mn accumulation. In addition, overexpression of AtNRAMP3 downregulates the expression of the primary Fe uptake transporter IRT1 and of the root ferric chelate reductase FRO2. Expression of AtNRAMP3::GFP fusion protein in onion cells or Arabidopsis protoplasts shows that AtNRAMP3 protein localizes to the vacuolar membrane. To account for the results presented, we propose that AtNRAMP3 influences metal accumulation and IRT1 and FRO2 gene expression by mobilizing vacuolar metal pools to the cytosol.

  11. Multistimuli-Responsive, Moldable Supramolecular Hydrogels Cross-Linked by Ultrafast Complexation of Metal Ions and Biopolymers.

    Science.gov (United States)

    Sun, Zhifang; Lv, Fucong; Cao, Lujie; Liu, Lin; Zhang, Yi; Lu, Zhouguang

    2015-06-26

    A new type of multistimuli-responsive hydrogels cross-linked by metal ions and biopolymers is reported. By mixing the biopolymer chitosan (CS) with a variety of metal ions at the appropriate pH values, we obtained a series of transparent and stable hydrogels within a few seconds through supramolecular complexation. In particular, the CS-Ag hydrogel was chosen as the model and the gelation mechanism was revealed by various measurements. It was found that the facile association of Ag(+) ions with amino and hydroxy groups in CS chains promoted rapid gel-network formation. Interestingly, the CS-Ag hydrogel exhibits sharp phase transitions in response to multiple external stimuli, including pH value, chemical redox reactions, cations, anions, and neutral species. Furthermore, this soft matter showed a remarkable moldability to form shape-persistent, free-standing objects by a fast in situ gelation procedure.

  12. Modulating effects of orally supplied Euglena gracilis on the physiological responses of the freshwater mussel Diplodon chilensis, exposed to sewage water pollution in a Patagonian river (Argentina).

    Science.gov (United States)

    Bianchi, Virginia A; Castro, Juan M; Rocchetta, Iara; Conforti, Visitación; Pascual, Mariano; Luquet, Carlos M

    2016-04-01

    In order to test if orally supplied Euglena sp. cells modulate the physiological status of bivalves during bioremediation procedures, we evaluated the effect of Euglena gracilis diet on the immune response, oxidative balance and metabolic condition of Diplodon chilensis exposed to sewage water pollution. Mussels were fed for 90 days with E. gracilis (EG) or Scenedesmus vacuolatus (SV, control diet), and then exposed for 10 days at three sites along the Pocahullo river basin: 1) an unpolluted site, upstream of the city (control, C); 2) upstream (UpS) and 3) downstream (DoS) from the main tertiary-treated sewage discharge, in the city of San Martín de los Andes, Northwest Patagonia, Argentina. Our results show that the total hemocyte number decreases while pollution load increases along the river course for both, EG and SV mussels. Phagocytic activity is higher in EG mussels than in SV ones under all conditions. Reactive oxygen species (ROS) production in hemocytes increases with the increase in the pollution load, being significantly higher for EG mussels than for SV ones at DoS; no changes are observed for total oxyradical scavenging capacity (TOSC). Hemocytes' viability is increased for E. gracilis diet at C and remains unchanged in this group of mussels when exposed at the polluted sites. Lysosomal membrane stability is higher in EG mussels than in SV ones for all conditions, although it is decreased at polluted sites compared with that at C. Antioxidant (catalase) and detoxifying (gluthatione S-transferase) defenses are generally lower in gills and digestive gland of EG mussels than in SV ones. Lipid peroxidation (TBARS) is evident in gills of EG mussels at C, and in digestive gland of the same group, at all the sites. Gill mass factor (GF) is affected by the E. gracilis diet; it is increased at C and decreased at polluted sites when compared with that of SV ones. Digestive gland mass factor (DGF) is higher in EG mussels than in SV ones. In D

  13. Palmitic acid feeding increases ceramide supply in association with increased milk yield, circulating nonesterified fatty acids, and adipose tissue responsiveness to a glucose challenge.

    Science.gov (United States)

    Rico, J E; Mathews, A T; Lovett, J; Haughey, N J; McFadden, J W

    2016-11-01

    Reduced insulin action is a key adaptation that facilitates glucose partitioning to the mammary gland for milk synthesis and enhances adipose tissue lipolysis during early lactation. The progressive recovery of insulin sensitivity as cows advance toward late lactation is accompanied by reductions in circulating nonesterified fatty acids (NEFA) and milk yield. Because palmitic acid can promote insulin resistance in monogastrics through sphingolipid ceramide-dependent mechanisms, palmitic acid (C16:0) feeding may enhance milk production by restoring homeorhetic responses. We hypothesized that feeding C16:0 to mid-lactation cows would enhance ceramide supply and ceramide would be positively associated with milk yield. Twenty multiparous mid-lactation Holstein cows were enrolled in a study consisting of a 5-d covariate, 49-d treatment, and 14-d posttreatment period. All cows were randomly assigned to a sorghum silage-based diet containing no supplemental fat (control; n=10; 138±45 d in milk) or C16:0 at 4% of ration dry matter (PALM; 98% C16:0; n=10; 136±44 d in milk). Blood and milk were collected at routine intervals. Liver and skeletal muscle tissue were biopsied at d 47 of treatment. Intravenous glucose tolerance tests (300mg/kg of body weight) were performed at d -1, 24, and 49 relative to start of treatment. The plasma and tissue concentrations of ceramide and glycosylated ceramide were determined using liquid chromatography coupled with tandem mass spectrometry. Data were analyzed as repeated measures using a mixed model with fixed effects of treatment and time, and milk yield served as a covariate. The PALM treatment increased milk yield, energy-corrected milk, and milk fat yield. The most abundant plasma and tissue sphingolipids detected were C24:0-ceramide, C24:0-monohexosylceramide (GlcCer), and C16:0-lactosylceramide. Plasma concentrations of total ceramide and GlcCer decreased as lactation advanced, and ceramide and GlcCer were elevated in cows fed PALM

  14. Water supply and demand in an energy supply model

    Energy Technology Data Exchange (ETDEWEB)

    Abbey, D; Loose, V

    1980-12-01

    This report describes a tool for water and energy-related policy analysis, the development of a water supply and demand sector in a linear programming model of energy supply in the United States. The model allows adjustments in the input mix and plant siting in response to water scarcity. Thus, on the demand side energy conversion facilities can substitute more costly dry cooling systems for conventional evaporative systems. On the supply side groundwater and water purchased from irrigators are available as more costly alternatives to unappropriated surface water. Water supply data is developed for 30 regions in 10 Western states. Preliminary results for a 1990 energy demand scenario suggest that, at this level of spatial analysis, water availability plays a minor role in plant siting. Future policy applications of the modeling system are discussed including the evaluation of alternative patterns of synthetic fuels development.

  15. Supply chain finance

    Directory of Open Access Journals (Sweden)

    Kasavica Petar

    2014-01-01

    Full Text Available The concept of supply chain finance is a response to global illiquidity, intensified through the global economic crisis and globalization of commercial and financial flows. The growing illiquidity undermines credit ratings of economic entities, thereby reducing the potential for achieving the projected goals (profitability and portfolio quality. In order to overcome this, banks have introduced certain products flexible to the requirements of specific transactions. The concerned products redirect the focus from a client's credit rating and risk to the credit rating and risk of a business partner (buyer, resulting in benefits for all transaction participants ('win-win-win'. Moreover, the activities are targeted at transaction analysis, i.e. the isolation and protection of the cash flow as the source of financial instrument's repayment. On the other hand, there has been an increasing number of transactions based on the risk of the commercial bank of the client's business partner, or on the risk of collateral (inventory. The focus is actually placed on the financing of adequate supply chain stages, given that counterparty relationship management has been proven to be crucial for efficient management of one's own business. The tensions existing in the relations between partners (increasingly long payment deadlines are in the basis of the supply chain finance concept. Decisions made by banks are based on the entire supply chain (wide information basis, thereby shifting the focus from the product (as was the case before the crisis to the client's needs. Thus, decisions become increasingly comprehensive, quicker, and more precise, and portfolios less risky. Through the individual portfolio of banks, the market of national economies also becomes safer and more liquid. These are rather profitable transactions, because, due to the risk transfer, financing is enabled to companies to whom classic crediting in most cases is not available.

  16. Transcriptional impact of organophosphate and metal mixtures on olfaction: Copper dominates the chlorpyrifos-induced response in adult zebrafish

    OpenAIRE

    Tilton, Fred A.; Tilton, Susan C.; Bammler, Theo K.; Beyer, Richard P; Stapleton, Patricia L.; Nathaniel L Scholz; Gallagher, Evan P.

    2011-01-01

    Chemical exposures in fish have been linked to loss of olfaction leading to an inability to detect predators and prey and decreased survival. However, the mechanisms underlying olfactory neurotoxicity are not well characterized, especially in environmental exposures which involve chemical mixtures. We used zebrafish to characterize olfactory transcriptional responses by two model olfactory inhibitors, the pesticide chlorpyrifos (CPF) and mixtures of CPF with the neurotoxic metal copper (Cu). ...

  17. Guest-responsive function of a dynamic metal-organic framework with a π Lewis acidic pore surface.

    Science.gov (United States)

    Joarder, Biplab; Mukherjee, Soumya; Chaudhari, Abhijeet K; Desai, Aamod V; Manna, Biplab; Ghosh, Sujit K

    2014-11-17

    A 3D dynamic coordination framework with an electron-deficient pore surface has been synthesized by using Zn(II) (having a variable coordination number) and a predesigned flexible π-electron-deficient core-based ligand, exhibiting chemical separations based on pore surface functionalization (π Lewis acidic pore surfaces and open metal sites) and framework flexibility, giving rise to a unique smart guest-responsive material.

  18. Cross-species transcriptional network analysis reveals conservation and variation in response to metal stress in cyanobacteria

    Science.gov (United States)

    2013-01-01

    Background As one of the most dominant bacterial groups on Earth, cyanobacteria play a pivotal role in the global carbon cycling and the Earth atmosphere composition. Understanding their molecular responses to environmental perturbations has important scientific and environmental values. Since important biological processes or networks are often evolutionarily conserved, the cross-species transcriptional network analysis offers a useful strategy to decipher conserved and species-specific transcriptional mechanisms that cells utilize to deal with various biotic and abiotic disturbances, and it will eventually lead to a better understanding of associated adaptation and regulatory networks. Results In this study, the Weighted Gene Co-expression Network Analysis (WGCNA) approach was used to establish transcriptional networks for four important cyanobacteria species under metal stress, including iron depletion and high copper conditions. Cross-species network comparison led to discovery of several core response modules and genes possibly essential to metal stress, as well as species-specific hub genes for metal stresses in different cyanobacteria species, shedding light on survival strategies of cyanobacteria responding to different environmental perturbations. Conclusions The WGCNA analysis demonstrated that the application of cross-species transcriptional network analysis will lead to novel insights to molecular response to environmental changes which will otherwise not be achieved by analyzing data from a single species. PMID:23421563

  19. Multiple stressor effects on marine infauna: responses of estuarine taxa and functional traits to sedimentation, nutrient and metal loading

    KAUST Repository

    Ellis, Joanne

    2017-09-14

    Sedimentation, nutrients and metal loading to coastal environments are increasing, associated with urbanization and global warming, hence there is a growing need to predict ecological responses to such change. Using a regression technique we predicted how maximum abundance of 20 macrobenthic taxa and 22 functional traits separately and interactively responded to these key stressors. The abundance of most taxa declined in response to sedimentation and metal loading while a unimodal response was often associated with nutrient loading. Optimum abundances for both taxa and traits occurred at relatively low stressor levels, highlighting the vulnerability of estuaries to increasing stressor loads. Individual taxa were more susceptible to stress than traits, suggesting that functional traits may be less sensitive for detecting changes in ecosystem health. Multiplicative effects were more common than additive interactions. The observed sensitivity of most taxa to increasing sedimentation and metal loading and the documented interaction effects between multiple stressors have important implications for understanding and managing the ecological consequences of eutrophication, sedimentation and contaminants on coastal ecosystems.

  20. 社会责任思想在供应链质量控制中的应用%The application of the idea of social responsibility in the quality control of supply chain

    Institute of Scientific and Technical Information of China (English)

    常广庶

    2013-01-01

    国际标准化组织新近发布了社会责任指南标准ISO26000,强调组织要实现可持续发展,就必须履行其社会责任.论文阐述了ISO26000社会责任思想的七个核心主题在供应链质量控制中的应用,以帮助企业按照ISO26000的社会责任思想来影响和规范供应链质量控制体系,使所有供应链成员企业都能够主动参与质量工作,并对整个供应链体系进行有效的质量监督与控制.%Recently, ISO published ISO26000 which emphasizes that the organization must perform its social responsibility to realize sustainable development. This paper analyzed the application of the seven core subiects of ISO26000 in quality control of supply chain so as to perfect the quality control system of supply chain according to the social responsibility idea of ISO26000, promote all the supply chain members participating into the quality control actively, and implement effective quality supervision and control over the whole supply chain system.

  1. Research on the Construction Strategy of Quick Response Apparel Supply Chain%快速响应型服装供应链的构建策略研究

    Institute of Scientific and Technical Information of China (English)

    马兰花

    2016-01-01

    服装业是一个供需具有双重不确定性的行业,“快时尚”、“多品种小批量”发展趋势,要求企业具有快速响应型供应链与之匹配。文中从我国服装企业供应链的现状出发,分析其存在的不足,就如何能够对顾客需求做出快速响应、实现供需平衡提出了的具体措施。%Garment industry is an industry with double uncertainty of supply and demand,the development trend of“fast fashion”,“multi variety and small batch”,requires the enterprise to have a quick response supply chain.This article from the current situation of China's clothing enterprises supply chain,analysis of its shortcomings,on how to make a rapid response to customer demand,to achieve the balance between supply and demand of the specific measures.

  2. Responses to reduced industrial metal emissions : An ecotoxicological study on Pied Flycatcher (Ficedula hypoleuca, Aves)

    OpenAIRE

    Berglund, Åsa

    2010-01-01

    Metals have been used by humans for thousands of years, and this has resulted in increased concentrations in the biosphere. The environment around point-sources, such as mines and smelters, are of particular concern, as metals may accumulate to high concentrations, and potentially reach levels toxic to the local flora and fauna. This thesis focuses on the effects on pied flycatcher populations of two such point-sources, a lead mine and enrichment plant, and a sulfide ore smelter. Mining activ...

  3. Is metal contamination responsible for increasing aneuploidy levels in the Manila clam Ruditapes philippinarum?

    KAUST Repository

    Piló, D.

    2016-11-03

    The present study assessed the metal genotoxicity potential at chromosome-level in the bivalve Ruditapes philippinarum collected along different areas of the Tagus estuary. Higher levels of aneuploidy on gill cells were detected at the most sediment contaminated area both in May (31.7%) and October (36.0%) when compared to a less contaminated area over the same periods (20.3% and 29.0% respectively). Interestingly, metal bioaccumulation in gills was higher in the specimens collected at the least contaminated area with the exception of Pb. Indeed, the multivariate analysis revealed a stronger relation between aneuploidy and sediment contamination than between aneuploidy and the bioaccumulation of the metals. The temporal and spatial inconsistency found for the bioaccumulation of metals in R. philippinarum and the positive correlation between sediment contamination and aneuploidy at the most contaminated area suggest that these chromosome-level effects might be due to chronic metal contamination occurring in the Tagus estuary, rather than a direct result of the temporal variation of bioavailable contaminants. The vertical transmission phenomenon of bivalve aneuploidy levels may then be perpetuating those levels on clams from the most contaminated area. The present results shed light about the effect of metal toxicity at the chromosome-level in species inhabiting chronic contaminated areas and highlight the use of aneuploidy as an effective tool to identify persistent contamination in worldwide transitional waters.

  4. Development of a fast thermal response microfluidic system using liquid metal

    Science.gov (United States)

    Gao, Meng; Gui, Lin

    2016-07-01

    Room temperature liquid metal gallium alloy has been widely used in many micro-electromechanical systems applications, such as on-chip electrical microheaters, micro temperature sensors, micro pumps and so on. Injecting liquid metal into microchannels can provide a simple, rapid, low-cost but efficient way to integrate these elements in microfluidic chips with high accuracy. The liquid metal-filled microstructures can be designed in any shape and easily integrated into microfluidic chips. In this paper, an on-chip liquid metal-based thermal microfluidic system is proposed for quick temperature control at the microscale. The micro system utilizes just one microfluidic chip as a basic working platform, which has liquid metal-based on-chip heaters, temperature sensors and electroosmotic flow pumps. Under the comprehensive control of these elements, the micro system can quickly change the temperature of a target fluid in the microfluidic chip. These liquid metal-based on-chip elements are very helpful for the fabrication and miniaturization of the microfluidic chip. In this paper, deionized water is used to test the temperature control performance of the thermal microfluidic system. According to the experimental results, the micro system can efficiently control the temperature of water ranging from 28 °C to 90 °C. The thermal microfluidic system has great potential for use in many microfluidic applications, such as on-chip polymerase chain reaction, temperature gradient focusing, protein crystallization and chemical synthesis.

  5. Response and Bioaccumulation Potential of Boerhavia diffusa L. Towards Different Heavy Metals

    Directory of Open Access Journals (Sweden)

    Abdussalam A.K.

    2013-08-01

    Full Text Available Effect of different concentrations of heavy metals such as Cadmium, Chromium, Mercury and Leadwas studied by cultivating rooted propagules of Boerhavia diffusafor a period of twenty days in Hoagland nutrient medium artificially contaminated with known concentration of those heavy metal ions. Concentrations of the metals selected to impart visible symptoms of growth retardation and to permit survival for prolonged period are 30µM cadmium chloride (CdCl2, 400 µM potassium dichromate (K2Cr2O7, 10 µM mercuric chloride (HgCl2, and 600 µM lead acetate (CH3-COO2Pb. More or less uniform growth performance was shown by the plants irrespective of the differences of concentration of the heavy metals. However, parameters such as root - and stem length, stomatal - and tolerance index varied among the treatments. Significant differences were observed in the heavy metal accumulation potential among metals and between plant parts such as root, stem and leaf and the pattern was dependent on growth period.

  6. Is metal contamination responsible for increasing aneuploidy levels in the Manila clam Ruditapes philippinarum?

    Science.gov (United States)

    Piló, D; Carvalho, S; Pereira, P; Gaspar, M B; Leitão, A

    2017-01-15

    The present study assessed the metal genotoxicity potential at chromosome-level in the bivalve Ruditapes philippinarum collected along different areas of the Tagus estuary. Higher levels of aneuploidy on gill cells were detected at the most sediment contaminated area both in May (31.7%) and October (36.0%) when compared to a less contaminated area over the same periods (20.3% and 29.0% respectively). Interestingly, metal bioaccumulation in gills was higher in the specimens collected at the least contaminated area with the exception of Pb. Indeed, the multivariate analysis revealed a stronger relation between aneuploidy and sediment contamination than between aneuploidy and the bioaccumulation of the metals. The temporal and spatial inconsistency found for the bioaccumulation of metals in R. philippinarum and the positive correlation between sediment contamination and aneuploidy at the most contaminated area suggest that these chromosome-level effects might be due to chronic metal contamination occurring in the Tagus estuary, rather than a direct result of the temporal variation of bioavailable contaminants. The vertical transmission phenomenon of bivalve aneuploidy levels may then be perpetuating those levels on clams from the most contaminated area. The present results shed light about the effect of metal toxicity at the chromosome-level in species inhabiting chronic contaminated areas and highlight the use of aneuploidy as an effective tool to identify persistent contamination in worldwide transitional waters. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. 供应链企业间知识共享的合作响应博弈分析%Game analysis of knowledge sharing among enterprises in supply chain based on cooperation response

    Institute of Scientific and Technical Information of China (English)

    孔祥西; 程钧谟; 张金山

    2016-01-01

    针对供应链企业间知识共享博弈存在的问题,引入了合作响应的概念,通过构建供应链企业间知识共享的合作响应博弈模型,分别对主动响应和被动响应两种状态下供应链企业间的知识共享进行了博弈分析,得到了供应链企业在知识共享过程中采取主动、被动响应策略的条件以及子博弈的纳什均衡解,并通过算例验证了结论的合理性。%For the game problem of knowledge sharing among supply chain enterprises,the con-cept of cooperative response was introduced.Through building the cooperation response game model of knowledge sharing among supply chain enterprises,the knowledge sharing game among supply chain enterprises were analyzed under the conditions of initiative response and passive re-sponse.Finally,the conditions which enterprise takes initiative response strategy or passive re-sponse strategy in the process of knowledge sharing among supply chain enterprises were ob-tained,and the two solutions of sub-game Nash equilibrium were found out.And through the ex-ample,the rationality of the conclusion is proved.

  8. Changes in fruit sugar concentrations in response to assimilate supply, metabolism and dilution: a modeling approach applied to peach fruit (Prunus persica).

    Science.gov (United States)

    Génard, M; Lescourret, F; Gomez, L; Habib, R

    2003-04-01

    The influence of assimilate supply, metabolism and dilution on sugar concentrations in the mesocarp of peach (Prunus persica (L.) Batsch) fruit during the main stage of fruit enlargement was analyzed with the SUGAR model of Génard and Souty (1996). The model predicts the partitioning of carbon into sucrose, sorbitol, glucose and fructose in the mesocarp of peach fruit. Based on measured data and the model, we determined values for the relative rates of sugar transformation. These rates were constant, varied with time or varied with relative fruit growth rate, depending on the type of sugar. Equations were derived to describe these rates and incorporated into the SUGAR model. The model simulated the effects of changing assimilate supply and fruit volume on sugar concentrations. The set of equations for the SUGAR model was rewritten to include the three components influencing sugar concentrations: assimilate supply, metabolism and dilution. The sugar types differed in sensitivity to these components. Sucrose was highly sensitive to changes in assimilate supply and to the dilution effect; it was not subject to intense metabolic transformation. Sorbitol was the most important carbohydrate in fruit metabolism, which explains why the sorbitol concentration was always low despite the strong positive effect of assimilate supply. The reducing sugars constituted a transitory storage pool and their concentrations were closely related to metabolism.

  9. The effects of Aphis fabae infestation on the antioxidant response and heavy metal content in field grown Philadelphus coronarius plants

    Energy Technology Data Exchange (ETDEWEB)

    Kafel, Alina, E-mail: akafel@us.edu.pl [University of Silesia, Department of Animal Physiology and Ecotoxicology, Bankowa 9, PL 40-007, Katowice (Poland); Nadgorska-Socha, Aleksandra [University of Silesia, Department of Ecology, Bankowa 9, PL 40-007, Katowice (Poland); Gospodarek, Janina [Agricultural University of Krakow, Department of Agricultural Environment Protection, Mickiewicza 21, PL 31-120, Krakow (Poland); Babczynska, Agnieszka; Skowronek, Magda [University of Silesia, Department of Animal Physiology and Ecotoxicology, Bankowa 9, PL 40-007, Katowice (Poland); Kandziora, Marta [University of Silesia, Department of Ecology, Bankowa 9, PL 40-007, Katowice (Poland); Rozpedek, Katarzyna [University of Silesia, Department of Animal Physiology and Ecotoxicology, Bankowa 9, PL 40-007, Katowice (Poland)

    2010-02-01

    The purpose of this study was to explore a possible relationship between the soil availability of metals and their concentrations in various parts of Philadelphuscoronarius plants. Moreover, the possible impact of an aphid infestation on the contamination and antioxidant response of plants from the urban environment of Krakow and the reference rural area of Zagaje Stradowskie (southern Poland) was analyzed. The contents of the glutathione, proline, non-protein - SH groups, antioxidants, and phosphorous and the levels of guaiacol peroxidase and catalase activity in leaves and shoots either infested or not by the aphid Aphis fabae Scop., were measured. The potential bioavailability of metals (Cd; Cu; Ni; Pb; Zn) in the soil and their concentrations in P. coronarius plants originating from both sites were compared. The antioxidant responses were generally elevated in the plants in the polluted area. Such reactions were additionally changed by aphid infestation. Generally, the concentrations of metals in the HNO{sub 3} and CaCl{sub 2} extractants of the soils from two layers at the 0-20 and 20-40 cm depths from the polluted area were higher than in those from the reference area. Such differences were found for nickel and lead (in all examined extractants), zinc (in soil extractants from the layer at 20-40 cm) and cadmium (in HNO{sub 3} extractants). Significant positive relationships between the lead concentrations in the soil and in the plants were found. In the parts of plants from the polluted area, higher concentrations of Pb and Zn (leaves and shoots) and Cd (shoots) were recorded. The shoots and leaves of plants infested with aphids had higher concentrations of Zn but lower Pb. Moreover, their leaves had higher contaminations of Cu and Ni. In conclusion, aphids affected not only the antioxidant response of the plants but also their contamination with metals, especially contamination of the leaves.

  10. Virginia Household Water Quality Program: Heavy Metals in Household Water

    OpenAIRE

    Ling, Erin; Benham, Brian Leslie, 1960-; Forrester, Scott

    2011-01-01

    Federal law requires public water utilities to provide biologically safe water. However, the safety of privately owned, individual water supplies such as wells, springs, and cisterns is the sole responsibility of the owner. This publication discusses the sources, testing, and treatment of heavy metals.

  11. Data on the histological and immune cell response in the popliteal lymph node in mice following exposure to metal particles and ions.

    Science.gov (United States)

    Winans, Bethany; Tvermoes, Brooke E; Unice, Kenneth M; Kovochich, Michael; Fung, Ernest S; Christian, Whitney V; Donovan, Ellen; Finley, Brent L; Kimber, Ian; Paustenbach, Dennis J

    2016-12-01

    Hip implants containing cobalt-chromium (CoCr) have been used for over 80 years. In patients with metal-on-metal (MoM) hip implants, it has been suggested that wear debris particles may contribute to metal sensitization in some individuals, leading to adverse reactions. This article presents data from a study in which the popliteal lymph node assay (PLNA) was used to assess immune responses in mice treated with chromium-oxide (Cr2O3) particles, metal salts (CoCl2, CrCl3, and NiCl2) or Cr2O3 particles with metal salts ("A preliminary evaluation of immune stimulation following exposure to metal particles and ions using the mouse popliteal lymph node assay" (B.E. Tvermoes, K.M. Unice, B. Winans, M. Kovochich, E.S. Fung, W.V. Christian, E. Donovan, B.L. Finley, B.L. Kimber, I. Kimber, D.J. Paustenbach, 2016) [1]). Data are presented on (1) the chemical characterization of TiO2 particles (used as a particle control), (2) clinical observations in mice treated with Cr2O3 particles, metal salts or Cr2O3 particles with metal salts, (3) PLN weight and weight index (WI) in mice treated with Cr2O3 particles, metal salts or Cr2O3 particles with metal salts, (4) histological changes in PLNs of mice treated with Cr2O3 particles, metal salts or Cr2O3 particles with metal salts, (5) percentages of immune cells in the PLNs of mice treated with Cr2O3 particles, metal salts or Cr2O3 particles with metal salts, and (6) percentages of proliferating cells in the PLNs of mice treated with Cr2O3 particles, metal salts or Cr2O3 particles with metal salts.

  12. Mineral supply for sustainable development requires resource governance

    Science.gov (United States)

    Ali, Saleem H.; Giurco, Damien; Arndt, Nicholas; Nickless, Edmund; Brown, Graham; Demetriades, Alecos; Durrheim, Ray; Enriquez, Maria Amélia; Kinnaird, Judith; Littleboy, Anna; Meinert, Lawrence D.; Oberhänsli, Roland; Salem, Janet; Schodde, Richard; Schneider, Gabi; Vidal, Olivier; Yakovleva, Natalia

    2017-03-01

    Successful delivery of the United Nations sustainable development goals and implementation of the Paris Agreement requires technologies that utilize a wide range of minerals in vast quantities. Metal recycling and technological change will contribute to sustaining supply, but mining must continue and grow for the foreseeable future to ensure that such minerals remain available to industry. New links are needed between existing institutional frameworks to oversee responsible sourcing of minerals, trajectories for mineral exploration, environmental practices, and consumer awareness of the effects of consumption. Here we present, through analysis of a comprehensive set of data and demand forecasts, an interdisciplinary perspective on how best to ensure ecologically viable continuity of global mineral supply over the coming decades.

  13. Response of geomorphic and geological processes to insufficient and ample sediment supply along the upper continental slope in the north-western South China Sea

    Indian Academy of Sciences (India)

    Hongjun Chen; Wenhuan Zhan; Shiguo Wu

    2016-12-01

    We document upper slope sedimentary process and strata on the passive margin of the north-western South China Sea (SCS) using multibeam bathymetry and high-resolution seismic data. The upper slope can be divided into two segments based on geomorphology, strata, and sediment supply. (1) The east segment is characterised by deep incised canyons and gullies, and slope failure. Submarine canyons with both U- and V-shaped morphology (13−28 km long × 2−4 km wide) are oriented NNE−SSW or NNW−SSE and are approximately perpendicular to the slope. Erosion is dominant, with escarpments, slumps, and several mass transport deposits (MTDs). Shelf-margin clinoforms show strongly upward vertical aggradation with time and are strongly aggradational in style. Since 5.5 Ma, the shelf break line migrated southwards and then retreated to its present position. The segment is classified as erosion-dominated due to insufficient sediment supply. (2) The west segment has a smooth surface, gentle gradient, and a strongly progradational style, with MTDs triggered by high sedimentation rates. Shelf-margin clinoforms display a combination of progradational and aggradational stacking patterns. The shelf break line migrated southwards with time. The segment is classified as deposition-dominated, resulting from plentiful sediment supply. Depositional models have been constructed for each segment: a constant shelf break model with insufficient sediment supply in the east, and a migration shelf break model with plenty sediment supply in the west. This case study contributes to the understanding of the upper slope sedimentary process and stratigraphic style under different sediment supply conditions.

  14. Response of geomorphic and geological processes to insufficient and ample sediment supply along the upper continental slope in the north-western South China Sea

    Science.gov (United States)

    Chen, Hongjun; Zhan, Wenhuan; Wu, Shiguo

    2016-12-01

    We document upper slope sedimentary process and strata on the passive margin of the north-western South China Sea (SCS) using multibeam bathymetry and high-resolution seismic data. The upper slope can be divided into two segments based on geomorphology, strata, and sediment supply. (1) The east segment is characterised by deep incised canyons and gullies, and slope failure. Submarine canyons with both U- and V-shaped morphology (13-28 km long × 2-4 km wide) are oriented NNE-SSW or NNW-SSE and are approximately perpendicular to the slope. Erosion is dominant, with escarpments, slumps, and several mass transport deposits (MTDs). Shelf-margin clinoforms show strongly upward vertical aggradation with time and are strongly aggradational in style. Since 5.5 Ma, the shelf break line migrated southwards and then retreated to its present position. The segment is classified as erosion-dominated due to insufficient sediment supply. (2) The west segment has a smooth surface, gentle gradient, and a strongly progradational style, with MTDs triggered by high sedimentation rates. Shelf-margin clinoforms display a combination of progradational and aggradational stacking patterns. The shelf break line migrated southwards with time. The segment is classified as deposition-dominated, resulting from plentiful sediment supply. Depositional models have been constructed for each segment: a constant shelf break model with insufficient sediment supply in the east, and a migration shelf break model with plenty sediment supply in the west. This case study contributes to the understanding of the upper slope sedimentary process and stratigraphic style under different sediment supply conditions.

  15. Health supply chain management.

    Science.gov (United States)

    Zimmerman, Rolf; Gallagher, Pat

    2010-01-01

    This chapter gives an educational overview of: * The actual application of supply chain practice and disciplines required for service delivery improvement within the current health environment. * A rationale for the application of Supply Chain Management (SCM) approaches to the Health sector. * The tools and methods available for supply chain analysis and benchmarking. * Key supply chain success factors.

  16. Multi-metal contamination with uranium trend impact on aquatic environment and consequences for fish immune system and adaptive responses

    Energy Technology Data Exchange (ETDEWEB)

    Le Guernic, A.; Gagnaire, B. [IRSN/PRP-ENV/SERIS/LECO (France); Sanchez, W. [Institut national de l' environnement industriel et des risques - INERIS (France); Betoulle, S. [Champagne Ardenne University (France)

    2014-07-01

    Human activities have conducted to an increase of concentrations of various metals in aquatic ecosystems, including uranium. Its extraction and use have been rapidly magnified because of its role in the nuclear fuel cycle. These activities have led to high concentrations of uranium in the aquatic environment and thus a potential risk to exposed organisms, including fish. Consequences can be observed through metabolic and physiological responses, called biomarkers. Some biomarkers are interesting in order to evaluate the effects of metal contamination, among other immunotoxicity markers, antioxidant defenses and genotoxicity. The aims of this study are: i) to investigate the effects of a multi-metal contamination on a fish, the three-spined stickleback, Gasterosteus aculeatus, and ii) to observe the adaptive capacity of fish due to a combination of stress (chemical stress and biological stress). To meet the first objective, six water bodies (ponds and lakes) located in two departments (Cantal and Haute-Vienne, France) were chosen according to their proximity to old uranium mines and to their levels of metal contamination related to chemical processes appeared during extraction. 240 three-spined sticklebacks were caged for 28 days in the six selected sites. A battery of biomarkers was measured in fish sampled after 14 and 28 of caging. The results for the Haute-Vienne department showed that caged fish in the pond with the highest uranium concentration (20 μg.L{sup -1}) presented the most DNA damage after 14 days of caging. Leukocyte phagocytosis (marker of immunotoxicity) of caged fish in this pond was lower at 14 days and greater at 28 days compared to other ponds without uranium. The multi-metal contamination negatively affected other parameters such as the condition index, oxidative activity, viability of lysosomal membrane and leukocytes distribution. In order to study the response of fish to a combined stress (chemical + biological) (objective ii), a second

  17. Spatial and temporal variability of heavy metals in streams of the Flint Creek and Flint River Watersheds from non-point sources

    OpenAIRE

    I. Abdi; T. Tsegaye; Silitonga, M.; Tadesse, W

    2009-01-01

    Throughout the United States, non-point pollution is responsible for large quantities of heavy metals entering bodies of water. Pollution as a result of heavy metals can impact drinking water supplies, recreation, fisheries, and aquatic species. Presence of heavy metals such as lead (Pb), cadmium (Cd), and chromium (Cr), in surface water may pose great risks to human health as well as to aquatic animals. In order to understand water quality changes due to heavy metal element...

  18. Influence of Mining Pollution on Metal Bioaccumulation and Biomarker Responses in Cave Dwelling Fish, Clarias gariepinus.

    Science.gov (United States)

    du Preez, Gerhard; Wepener, Victor

    2016-07-01

    Cave ecosystems remain largely unstudied and risk being severely degraded as a result of anthropogenic activities. The Wonderfontein Cave, situated in the extensive gold mining region of the Witwatersrand Basin, is one such system that hosts a population of Clarias gariepinus, which is exposed to the influx of polluted mine water from the Wonderfontein Spruit River. The aim of this study was to investigate the bioaccumulation of metals, as well as relevant biomarkers, in C. gariepinus specimens sampled from the Wonderfontein Cave during high (April 2013) and low (September 2013) flow surveys. Results were also compared to a surface population associated with the Wonderfontein Spruit River. There were temporal differences in metal bioaccumulation patterns and this was attributed to the lack of dilution during the low flow period. Metals associated with acid mine drainage, i.e. Co, Mn and Zn were significantly higher in the Wonderfontein Cave population and were reflected in an increase in oxidative stress biomarkers (catalase, protein carbonyls and superoxide dismutase) and the induction of metallothionein, a biomarker of metal exposure. The surface population was exposed to metals associated with geological weathering processes, i.e. Fe and Al.

  19. MOLECULAR DYNAMICS INVESTIGATION OF DEFORMATION RESPONSE OF THIN-FILM METALLIC NANOSTRUCTURES UNDER HEATING

    OpenAIRE

    KONOVALENKO IVAN; ZOLNIKOV KONSTANTIN; PSAKHIE SERGEY

    2011-01-01

    Molecular dynamics simulation of nanostructure behavior under impulse heating is carried out. These structures are formed by self-rolling of nano-thickness bilayer crystal films. The interatomic interactions are described by potentials obtained by the embedded atom method. The calculation data are shown that simulated nanostructures can transform the supplied thermal energy into the mechanical oscillations of its free edges. The influence of heating rate and its duration, medium viscosity pro...

  20. Physiological and proteomic responses of different willow clones (Salix fragilis x alba) exposed to dredged sediment contaminated by heavy metals.

    Science.gov (United States)

    Evlard, Aricia; Sergeant, Kjell; Ferrandis, Salvador; Printz, Bruno; Renaut, Jenny; Guignard, Cedric; Paul, Roger; Hausman, Jean-Francois; Campanella, Bruno

    2014-01-01

    High biomass producing species are considered as tools for remediation of contaminated soils. Willows (Salix spp.) are prominent study subjects in this regard. In this study, different willow clones (Salix fragilis x alba) were planted on heavy-metal polluted dredging sludge. A first objective was assessment of the biomass production for these clones. Using a Gupta statistic, four clones were identified as high biomass producers (HBP). For comparison, a group of four clones with lowest biomass production were selected (LBP). A second objective was to compare metal uptake as well as the physiological and proteomic responses of these two groups. All these complementary data's allow us to have a better picture of the health of the clones that would be used in phytoremediation programs. Cd, Zn, and Ni total uptake was higher in the HBPs but Pb total uptake was higher in LBPs. Our proteomic and physiological results showed that the LBPs were able to maintain cellular activity as much as the HBPs although the oxidative stress response was more pronounced in the LBPs. This could be due to the high Pb content found in this group although a combined effect of the other metals cannot be excluded.

  1. Antioxidant response to metal pollution in Phragmites australis from Anzali wetland.

    Science.gov (United States)

    Esmaeilzadeh, Marjan; Karbassi, Abdolreza; Bastami, Kazem Darvish

    2017-03-21

    This research was conducted to examine variations of antioxidant enzyme activity in Phragmites australis as a biomarker for metals such as As, Pb, Cu, and Cd. Samples of sediment and plants were collected from 7 stations located in Anzali wetland. Biochemical parameters including Catalase, Peroxidase and Ascorbate Peroxidase activity were analyzed in the roots, stems and leaves of P. australis. The obtained results indicated that there were significant differences among activities of antioxidant enzymes in three organs (p<0.05). Antioxidant enzyme activities in the organs for all studied stations were as the following order: stemmetals in sediments and activities of antioxidant enzymes in P. australis. As a result, it can be concluded from this study that antioxidant enzymes are good biomarkers reflecting metal contamination in sediments of Anzali wetland.

  2. Photosynthesis and growth responses of pea Pisum sativum L. under heavy metals stress

    Institute of Scientific and Technical Information of China (English)

    Sabrine Hattab; Boutheina Dridi; Lassad Chouba; Mohamed Ben Kheder; Hamadi Bousetta

    2009-01-01

    The present work aims to study the physiological effects of cadmium (Cd) and copper (Cu) in pea (Pisum sativum).Pea plants were exposed to increasing doses of cadmium chloride (CdCl_2) and copper chloride (CuCl_2) for 20 d.The examined parameters,namely root and shoot lengths,the concentration of photosynthetic pigments and the rate of photosynthesis were affected by the treatments especially with high metals concentrations.The analysis of heavy metals accumulation shows that leaves significantly accumulate cadmium for all the tested concentrations.However,copper was significantly accumulated only with the highest tested dose.This may explain the higher inhibitory effects of cadmium on photosynthesis and growth in pea plants.These results are valuable for understanding the biological consequences of heavy metals contamination particularly in soils devoted to organic agriculture.

  3. Determination of heavy metals contamination using a silicon sensor with extended responsive to the UV

    Science.gov (United States)

    Aceves-Mijares, M.; Ramírez, J. M.; Pedraza, J.; Román-López, S.; Chávez, C.

    2013-03-01

    Due to its potential risk to human health and ecology, the presence of heavy metals in water demands of techniques to determine them in a simple and economical way. Currently, new developments of light emitters and detectors open a window of opportunities to use optical properties to analyze contaminated water. In this paper, a silicon sensor developed to extend its sensitivity up to the UV range is used to determine heavy metals in water. Cadmium, Zinc, Lead, Copper and Manganese mixed in pure water at different concentrations were used as test samples. The photocurrent obtained by the light that passes through the samples was used to determine the optical transmittance of pure and contaminated water. Preliminary results show a good separability between samples, which can be used for qualitative and quantitative detection of such heavy metals in water.

  4. Cardiopulmonary responses of intratracheally instilled tire particles and constituent metal components

    Science.gov (United States)

    Gottipolu, R.R.; Landa, E.R.; Schladweiler, M.C.; McGee, J.K.; Ledbetter, A.D.; Richards, J.H.; Wallenborn, G.J.; Kodavanti, U.P.

    2008-01-01

    Tire and brake wear particles contain transition metals, and contribute to near-road PM. We hypothesized that acute cardiopulmonary injury from respirable tire particles (TP) will depend on the amount of soluble metals. Respirable fractions of two types of TP (TP1 and TP2) were analyzed for water and acid-leachable metals using ICP-AES. Both TP types contained a variety of transition metals, including zinc (Zn), copper (Cu), aluminum, and iron. Zn and Cu were detected at high levels in water-soluble fractions (TP2 > TP1). Male Wistar Kyoto rats (12-14 wk) were intratracheally instilled, in the first study, with saline, TP1 or TP2 (5 mg/kg), and in the second study, with soluble Zn, Cu (0.5 ??mol/kg), or both. Pulmonary toxicity and cardiac mitochondrial enzymes were analyzed 1 d, 1 wk, or 4 wk later for TP and 4 or 24 h later for metals. Increases in lavage fluid markers of inflammation and injury were observed at d 1 (TP2 > TP1), but these changes reversed by wk 1. No effects on cardiac enzymes were noted with either TP. Exposure of rats to soluble Zn and Cu caused marked pulmonary inflammation and injury but temporal differences were apparent (Cu effects peaked at 4 h and Zn at 24 h). Instillation of Zn, Cu, and Zn+ Cu decreased the activity of cardiac aconitase, isocitrate dehydrogenase, succinate dehydrogenase, cytochrome-c-oxidase and superoxide dismutase suggesting mitochondrial oxidative stress. The observed acute pulmonary toxicity of TP could be due to the presence of water soluble Zn and Cu. At high concentrations these metals may induce cardiac oxidative stress. Copyright ?? Informa Healthcare USA, Inc.

  5. Responses of the alga Pseudokirchneriella subcapitata to long-term exposure to metal stress

    Energy Technology Data Exchange (ETDEWEB)

    Machado, Manuela D. [Bioengineering Laboratory, Chemical Engineering Department, ISEP-School of Engineering of Polytechnic Institute of Porto, Porto (Portugal); CEB-Centre of Biological Engineering, University of Minho, Braga (Portugal); Lopes, Ana R. [LEPABE, Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Porto (Portugal); Soares, Eduardo V., E-mail: evs@isep.ipp.pt [Bioengineering Laboratory, Chemical Engineering Department, ISEP-School of Engineering of Polytechnic Institute of Porto, Porto (Portugal); CEB-Centre of Biological Engineering, University of Minho, Braga (Portugal)

    2015-10-15

    Highlights: • Heavy metals provoke a perturbation of the physiological status of Pseudokirchneriella subcapitata. • Cd(II), Cr(VI) and Cu(II), at high concentrations, cause the loss of membrane integrity. • Cd(II), Cr(VI), Cu(II) and Zn(II) inhibit esterase activity in a dose dependent manner. • Heavy metals affect mitochondrial function and photosynthetic activity. • Fluorescent probes are a useful tool in the identification of toxicity targets of the heavy metals. - Abstract: The green alga Pseudokirchneriella subcapitata has been widely used in ecological risk assessment, usually based on the impact of the toxicants in the alga growth. However, the physiological causes that lead algal growth inhibition are not completely understood. This work aimed to evaluate the biochemical and structural modifications in P. subcapitata after exposure, for 72 h, to three nominal concentrations of Cd(II), Cr(VI), Cu(II) and Zn(II), corresponding approximately to 72 h-EC{sub 10} and 72 h-EC{sub 50} values and a high concentration (above 72 h-EC{sub 90} values). The incubation of algal cells with the highest concentration of Cd(II), Cr(VI) or Cu(II) resulted in a loss of membrane integrity of ~16, 38 and 55%, respectively. For all metals tested, an inhibition of esterase activity, in a dose-dependent manner, was observed. Reduction of chlorophyll a content, decrease of maximum quantum yield of photosystem II and modification of mitochondrial membrane potential was also verified. In conclusion, the exposure of P. subcapitata to metals resulted in a perturbation of the cell physiological status. Principal component analysis revealed that the impairment of esterase activity combined with the reduction of chlorophyll a content were related with the inhibition of growth caused by a prolonged exposure to the heavy metals.

  6. Research on Clothing Supply Chain Integrated Models Based on Quick Response%浅析信息化时代基于时间竞争的快速物流服务

    Institute of Scientific and Technical Information of China (English)

    顾燕菁

    2016-01-01

    能否提供快速的物流服务已经成为衡量物流企业竞争力的一项重要指标。现代意义上的竞争不是企业间的竞争而是供应链之间的竞争,供应链整体优化,以及信息共享是快速物流服务发展的基础。文中以服装行业为例,阐述了提供快速物流服务对提升供应链竞争力的意义。%Now whether a logistics company can provide its service just in time and respond to the various markets and customer demand shows the company’s core competitiveness.The integration of information,processes,organization of supply chain provides the basis for fast response.This paper will take clothes industry as an example to elaborate the significance importance of integrated supply chain based on quick response to promote the supply chain competitiveness.Finally the paper will give some suggestions to improve its quick response capability.

  7. Implications of end-user behaviour in response to deficiencies in water supply for electricity consumption - A case study of Delhi

    Science.gov (United States)

    Ghosh, Ruchira; Kansal, Arun; Aghi, Sakshi

    2016-05-01

    Over the past two decades, urban lifestyles have changed phenomenally. One aspect of this change is the increasing use of household appliances, which, in turn, influences water and electricity consumption in urban households. It is therefore necessary to revisit water supply norms in view of these behavioural changes. Increasing use of water-related appliances by the surveyed households in Delhi, India has lowered their water consumption but increased their electricity consumption (10-16 kW h a month). Also, longer working hours away from homes have shifted water demand from homes to commercial establishments and institutions. The per-capita water requirement to meet the basic needs for health and hygiene is approximately 76-78 L a day, of which bathing claims the largest share (32%). Nearly 70% of electricity consumption of a household is spent in coping with deficiencies in water supply. Strategies adopted by end users to save water were negatively correlated with those to save electricity. Household incomes have no influence on water consumption except in the case of those living in slums, who are forced to curtail their use of water even at the cost of health and hygiene; for the rest, coping with poor water supply amounts to spending nearly 50% more on electricity, defeating the purpose of subsidised water supply.

  8. The delayed lung responses to single and repeated intratracheal administration of pure cobalt and hard metal powder in the rat

    Energy Technology Data Exchange (ETDEWEB)

    Lasfargues, G.; Lardot, C.; Lauwerys, R.; Lison, D. [Catholic Univ. of Louvain (Belgium)] [and others

    1995-05-01

    Epidemiological and clinical studies suggest that inhalation of cobalt metal dust (Co) mixed with tungsten carbide particles (WC), but not of cobalt dust alone, may cause interstitial pulmonary lesions (hard metal disease). In previous studies in the rat, we have demonstrated the greater acute pulmonary toxicity of a WC-Co mixture was greater compared to Co or WC alone. The present study compares the delayed lung response after intratracheal administration of Co or WC-Co particles. The responses were also compared with those obtained after treatment with arsenic trioxide and crystalline silica used as reference materials producing an acute toxic insult and progressive fibrogenic response, respectively. Cellular and biochemical parameters were measured in bronchoalveolar lavage fluid following single and repeated intratracheal instillations. The results indicate the delayed lung response observed after WC-Co is different from that after cobalt metal alone. A single intratracheal dose of WC-Co (1, 5, or 10 mg/100 g body wt) induced an acute alveolitis which persisted for at least 1 month. Four months after a single instillation of WC-Co, no clear histological lung fibrosis could however be evidenced, indicating a reversibility of the lesions. The effects of cobalt (0.06, 0.3, or 0.6 mg/100 g body wt) were very modest, if any. Following repeated intratracheal instillations, increased lung hydroxyproline content and histopathological evidence of interstitial fibrosis were observed after WC-Co (4x1 mg/100 g body wt), but not after administration of each component separately, i.e., Co (4x0.06 mg/100 g body wt) or WC (4x1 mg/100 g body wt). The mechanism of the fibrotic reaction induced by WC-Co seems different from the progressive inflammatory reaction induced by crystalline silica. We suggest that it might result from a scarring reaction elicited by repeated acute insults as observed after repeated administration of arsenic trioxide. 34 refs., 10 figs., 3 tabs.

  9. CLONING AND CHARACTERIZATION OF A METAL RESPONSIVE ELEMENT-CONTAINING FRAGMENT FROM THE WILSON DISEASE GENE LOCUS BY JUNCTION TRAPPING

    Institute of Scientific and Technical Information of China (English)

    谢久永; 刘国仰; 王梅; 黄尚志; 罗会元

    1998-01-01

    All mammalian metallothionaln genes studied to dare have several metal responsive elements (MRE) with consensus sequences of TGCRCNC (R, purlne) in their regulatory region. MRE-11ke sequeaees were also found in many other metal-related genes. To see whether there is also such a sequence at the genetic locus (13q14. 3) d Wilstm disease, which is a genetic disorder d copper metabolisa''n, junction-trapping method baaed on the MRE sequence was used. A fragment containing MRE and MRE-like sequences from YAC 27D8 at the WND locus was successfully cloned and mapped back to the YAC by PC, R, Presence of such a sequence in the copper transporter gene at the W''D locus might imply that it has a possible interesting role in the regulation of WD gene expression.

  10. Identification and response to metals of metallothionein in two ancient fishes: white sturgeon (Acipenser transmontanus) and lake sturgeon (Acipenser fulvescens).

    Science.gov (United States)

    Doering, Jon A; Beitel, Shawn C; Eisner, Bryanna K; Heide, Timon; Hollert, Henner; Giesy, John P; Hecker, Markus; Wiseman, Steve B

    2015-05-01

    White sturgeon (Acipenser transmontanus) are among the most sensitive species of fishes to Cu, Cd, and Zn, but there is no information about sensitivity of lake sturgeon (Acipenser fulvescens). To begin to elucidate molecular mechanism(s) of sensitivity of sturgeons to metals a cDNA encoding metallothionein (MT) was amplified from livers of white sturgeon (WS-MT) and lake sturgeon (LS-MT), and expression in response to Cu, Cd, or Zn was characterized in liver explants from each species. The primary structure of WS-MT and LS-MT contained 20 cysteine residues, which is the same as MTs of teleost fishes. However, the primary structure of WS-MT and LS-MT contained 63 amino acids, which is longer than any MT identified in teleost fishes. Abundance of transcripts of WS-MT in explants exposed to 0.3, 3, 30, or 100 μg/L of Cu was 1.7-, 1.7-, 2.1-, and 2.6-fold less than in controls, respectively. In contrast, abundances of transcripts of WS-MT were 3.3- and 2.4-fold greater in explants exposed to 30 μg/L of Cd and 1000 μg/L of Zn, respectively. Abundance of transcripts of LS-MT was not significantly different at any concentration of Cu, Cd, or Zn. MT is hypothesized to represent a critical mechanism for detoxification of metals. Therefore, results of this study suggest that sensitivity of sturgeons to exposure to Cu, Cd, or Zn might be a result of the relatively lesser maximal response of MT to metals. The study also suggestslake sturgeon might be more sensitive than white sturgeon to metals.

  11. Sustainability Analysis for Gayo Coffee Supply Chain

    Directory of Open Access Journals (Sweden)

    Rachman Jaya

    2013-01-01

    Full Text Available Sustainable supply chain is a development of the conventional supply chains that discuses trade-off among economic, social and environmental dimensions in order to achieve better responsiveness in terms of quality, quantity and time-delivery in the supply chain structure. The objective of this research was to determine the Gayo coffee supply chain sustainability. The research was conducted at Bener Meriah and Aceh Tengah Districts, Aceh Province, Indonesia. Key actors in the supply chain considered were farmers, collectors, agro-industry and exporter. Sustainability dimensions considered in this research were the economic, social, environmental and material resources. The performance of each aspect was analyzed by using Multi-dimensional scaling and leverage analysis. The result of the research showed that the composite of Gayo coffee supply chain sustainability index was 33.53 which mean less sustainable level. Therefore it is recommended to reengineering the Gayo coffee supply chain by considering all of the four sustainability dimensions above.

  12. Analysis of the Dynamic Response in Blast-Loaded CFRP-Strengthened Metallic Beams

    Directory of Open Access Journals (Sweden)

    Zhenyu Wang

    2013-01-01

    Full Text Available Carbon fiber-reinforced polymer composites (CFRPs are good candidates in enhancing the blast resistant performance of vulnerable public buildings and in reinforcing old buildings. The use of CFRP in retrofitting and strengthening applications is traditionally associated with concrete structures. Nevertheless, more recently, there has been a remarkable aspiration in strengthening metallic structures and components using CFRP. This paper presents a relatively simple analytical solution for the deformation and ultimate strength calculation of hybrid metal-CFRP beams when subjected to pulse loading, with a particular focus on blast loading. The analytical model is based on a full interaction between the metal and the FRP and is capable of producing reasonable results in a dynamic loading scenario. A nonlinear finite element (FE model is also developed to reveal the full dynamic behavior of the CFRP-epoxy-steel hybrid beam, considering the detailed effects, that is, large strains, high strain rates in metal, and different failure modes of the hybrid beam. Experimental results confirm the analytical and the FE results and show a strong correlation.

  13. Responses to Oxidative and Heavy Metal Stresses in Cyanobacteria: Recent Advances

    Directory of Open Access Journals (Sweden)

    Corinne Cassier-Chauvat

    2014-12-01

    Full Text Available Cyanobacteria, the only known prokaryotes that perform oxygen-evolving photosynthesis, are receiving strong attention in basic and applied research. In using solar energy, water, CO2 and mineral salts to produce a large amount of biomass for the food chain, cyanobacteria constitute the first biological barrier against the entry of toxics into the food chain. In addition, cyanobacteria have the potential for the solar-driven carbon-neutral production of biofuels. However, cyanobacteria are often challenged by toxic reactive oxygen species generated under intense illumination, i.e., when their production of photosynthetic electrons exceeds what they need for the assimilation of inorganic nutrients. Furthermore, in requiring high amounts of various metals for growth, cyanobacteria are also frequently affected by drastic changes in metal availabilities. They are often challenged by heavy metals, which are increasingly spread out in the environment through human activities, and constitute persistent pollutants because they cannot be degraded. Consequently, it is important to analyze the protection against oxidative and metal stresses in cyanobacteria because these ancient organisms have developed most of these processes, a large number of which have been conserved during evolution. This review summarizes what is known regarding these mechanisms, emphasizing on their crosstalk.

  14. Optical response of a quantum dot-metal nanoparticle hybrid interacting with a weak probe field.

    Science.gov (United States)

    Kosionis, Spyridon G; Terzis, Andreas F; Sadeghi, Seyed M; Paspalakis, Emmanuel

    2013-01-30

    We study optical effects in a hybrid system composed of a semiconductor quantum dot and a spherical metal nanoparticle that interacts with a weak probe electromagnetic field. We use modified nonlinear density matrix equations for the description of the optical properties of the system and obtain a closed-form expression for the linear susceptibilities of the quantum dot, the metal nanoparticle, and the total system. We then investigate the dependence of the susceptibility on the interparticle distance as well as on the material parameters of the hybrid system. We find that the susceptibility of the quantum dot exhibits optical transparency for specific frequencies. In addition, we show that there is a range of frequencies of the applied field for which the susceptibility of the semiconductor quantum dot leads to gain. This suggests that in such a hybrid system quantum coherence can reverse the course of energy transfer, allowing flow of energy from the metallic nanoparticle to the quantum dot. We also explore the susceptibility of the metal nanoparticle and show that it is strongly influenced by the presence of the quantum dot.

  15. Transcriptional and physiological responses of nitrifying bacteria to heavy metal inhibition

    Science.gov (United States)

    Heavy metals have been shown to inhibit nitrification, a key process in the removal of nitrogen in wastewater treatment plants. In the present study, the effects of nickel, zinc, lead and cadmium on nitrifying enrichment cultures were studied in batch reactors. The transcriptiona...

  16. Responses to oxidative and heavy metal stresses in cyanobacteria: recent advances.

    Science.gov (United States)

    Cassier-Chauvat, Corinne; Chauvat, Franck

    2014-12-31

    Cyanobacteria, the only known prokaryotes that perform oxygen-evolving photosynthesis, are receiving strong attention in basic and applied research. In using solar energy, water, CO2 and mineral salts to produce a large amount of biomass for the food chain, cyanobacteria constitute the first biological barrier against the entry of toxics into the food chain. In addition, cyanobacteria have the potential for the solar-driven carbon-neutral production of biofuels. However, cyanobacteria are often challenged by toxic reactive oxygen species generated under intense illumination, i.e., when their production of photosynthetic electrons exceeds what they need for the assimilation of inorganic nutrients. Furthermore, in requiring high amounts of various metals for growth, cyanobacteria are also frequently affected by drastic changes in metal availabilities. They are often challenged by heavy metals, which are increasingly spread out in the environment through human activities, and constitute persistent pollutants because they cannot be degraded. Consequently, it is important to analyze the protection against oxidative and metal stresses in cyanobacteria because these ancient organisms have developed most of these processes, a large number of which have been conserved during evolution. This review summarizes what is known regarding these mechanisms, emphasizing on their crosstalk.

  17. Transcriptional and physiological responses of nitrifying bacteria to heavy metal inhibition

    Science.gov (United States)

    Heavy metals have been shown to inhibit nitrification, a key process in the removal of nitrogen in wastewater treatment plants. In the present study, the effects of nickel, zinc, lead and cadmium on nitrifying enrichment cultures were studied in batch reactors. The transcriptiona...

  18. Biogeochemical Cycling of Nutrients and Trace Metals in the Sediment of Haringvliet Lake: Response to Salinization

    NARCIS (Netherlands)

    Canavan, R.W.

    2006-01-01

    This thesis examines sediment redox processes associated with organic matter degradation and their impact on the cycling of nutrients (N, P) and trace metals (Cd, Co, Ni, Pb, Zn). Our study site, Haringvliet Lake, is located in the Rhine-Meuse River Delta in the southwest of The Netherlands. This wa

  19. Multimodality Imaging of the Long-term Vascular Responses Following Implantation of Metallic and Bioresorbable Devices

    NARCIS (Netherlands)

    V.D. Gkogkas (Vasileios)

    2014-01-01

    markdownabstract__Abstract__ The pattern of vascular responses following stent/scaffold implantation in conventional interventional practice has been assessed by coronary angiography, intravascular ultrasound or optical coherence tomography and manifests as in-stent vascular response (focal or dif

  20. Collaborative Supply Chain Planning and Coordination

    DEFF Research Database (Denmark)

    Wong, Chee Yew

    This thesis contains main results from an industrial PhD research in the areas of supply chain strategy, planning, and coordination. It applies the concepts of responsiveness and coordination to reduce mismatch of supply and demand, especially for a volatile and seasonal supply chain. It involves...... products, differentiating retailers, accurate response (with forecast adjustment and premature replenishment), quick response (order-penetration-point relocation and lead-time reduction). These analyses extend the Fisher Model of responsiveness and refine six propositions or principles of responsiveness....... The thesis further explains the multi-characteristics of seasonal products in their life cycles and concludes an integrated framework of responsiveness. For coordination issue, the thesis develops a new bullwhip measure, and then quantifies and explains bullwhip effects in the toy supply chain. It also...

  1. The Effectors and Sensory Sites of Formaldehyde-responsive Regulator FrmR and Metal-sensing Variant *

    Science.gov (United States)

    Osman, Deenah; Piergentili, Cecilia; Chen, Junjun; Sayer, Lucy N.; Usón, Isabel; Huggins, Thomas G.; Robinson, Nigel J.; Pohl, Ehmke

    2016-01-01

    The DUF156 family of DNA-binding transcriptional regulators includes metal sensors that respond to cobalt and/or nickel (RcnR, InrS) or copper (CsoR) plus CstR, which responds to persulfide, and formaldehyde-responsive FrmR. Unexpectedly, the allosteric mechanism of FrmR from Salmonella enterica serovar Typhimurium is triggered by metals in vitro, and variant FrmRE64H gains responsiveness to Zn(II) and cobalt in vivo. Here we establish that the allosteric mechanism of FrmR is triggered directly by formaldehyde in vitro. Sensitivity to formaldehyde requires a cysteine (Cys35 in FrmR) conserved in all DUF156 proteins. A crystal structure of metal- and formaldehyde-sensing FrmRE64H reveals that an FrmR-specific amino-terminal Pro2 is proximal to Cys35, and these residues form the deduced formaldehyde-sensing site. Evidence is presented that implies that residues spatially close to the conserved cysteine tune the sensitivities of DUF156 proteins above or below critical thresholds for different effectors, generating the semblance of specificity within cells. Relative to FrmR, RcnR is less responsive to formaldehyde in vitro, and RcnR does not sense formaldehyde in vivo, but reciprocal mutations FrmRP2S and RcnRS2P, respectively, impair and enhance formaldehyde reactivity in vitro. Formaldehyde detoxification by FrmA requires S-(hydroxymethyl)glutathione, yet glutathione inhibits formaldehyde detection by FrmR in vivo and in vitro. Quantifying the number of FrmR molecules per cell and modeling formaldehyde modification as a function of [formaldehyde] demonstrates that FrmR reactivity is optimized such that FrmR is modified and frmRA is derepressed at lower [formaldehyde] than required to generate S-(hydroxymethyl)glutathione. Expression of FrmA is thereby coordinated with the accumulation of its substrate. PMID:27474740

  2. Expression and purification of full length mouse metal response element binding transcription factor-1 using Pichia pastoris.

    Science.gov (United States)

    Huyck, Ryan W; Keightley, Andrew; Laity, John H

    2012-09-01

    The metal response element binding transcription factor-1 (MTF-1) is an important stress response, heavy metal detoxification, and zinc homeostasis factor in eukaryotic organisms from Drosophila to humans. MTF-1 transcriptional regulation is primarily mediated by elevated levels of labile zinc, which direct MTF-1 to bind the metal response element (MRE). This process involves direct zinc binding to the MTF-1 zinc fingers, and zinc dependent interaction of the MTF-1 acidic region with the p300 coactivator protein. Here, the first recombinant expression system for mutant and wild type (WT) mouse MTF-1 (mMTF-1) suitable for biochemical and biophysical studies in vitro is reported. Using the methyltropic yeast Pichia pastoris, nearly half-milligram recombinant WT and mutant mMTF-1 were produced per liter of P. pastoris cell culture, and purified by a FLAG-tag epitope. Using a first pass ammonium sulfate purification, followed by anti-FLAG affinity resin, mMTF-1 was purified to >95% purity. This recombinant mMTF-1 was then assayed for direct protein-protein interactions with p300 by co-immunoprecipitation. Surface plasmon resonance studies on mMTF-1 provided the first quantitative DNA binding affinity measurements to the MRE promotor element (K(d)=5±3 nM). Both assays demonstrated the functional activity of the recombinant mMTF-1, while elucidating the molecular basis for mMTF-1-p300 functional synergy, and provided new insights into the mMTF-1 domain specific roles in DNA binding. Overall, this production system provides accessibility for the first time to a multitude of in vitro studies using recombinant mutant and WT mMTF-1, which greatly facilitates new approaches to understanding the complex and varied functions of this protein.

  3. PRINCIPLES OF THE SUPPLY CHAIN PERFORMANCE MEASUREMENT

    OpenAIRE

    BEATA ŒLUSARCZYK; SEBASTIAN KOT

    2012-01-01

    Measurement of performance in every business management is a crucial activity allowing for effectiveness increase. The lack of suitable performance measurement is especially noticed in complex systems as supply chains. Responsible persons cannot manage effectively without suitable set of measures those are base for comparison to previous data or effects of other supply chain functioning. The analysis shows that it is very hard to find balanced set of supply chain performance measures those sh...

  4. 基于网络治理视角的供应链企业社会责任研究%Research on Enterprise Social Responsibility Construction in Supply Chain Based on the Perspectives of Network Governance

    Institute of Scientific and Technical Information of China (English)

    周翼翔

    2015-01-01

    企业社会责任的范围已不再局限于某个企业,已扩展到供应链的不同环节。在供应链中,由于各企业的地位、利益分配以及企业社会责任表现各不相同,使得无论核心企业还是非核心企业都缺乏履行责任的动力。针对这种“囚徒困境”的局面,构建供应链企业社会责任推进模式,在经济刺激、协议约束、相互竞争的基础上结合外部治理,由点到链,再由链到网络治理逐步推进来解决我国目前企业社会责任缺失的现状。%At present, corporate social responsibility is no longer confined to the scope of an enterprise , but extended to different links of supply chain.In supply chain, the position, profit distribution, and corporate social responsibility performance of each enterprise are not identical, which makes both core and non-core enterprises lack of responsibility.According to the situation of"prisoner's dilemma", we construct the model to pro-mote corporate social responsibility in supply chain .Only from point to chain and then to network governance can we gradually change the current situation of deficient corporate social responsibility on the basis of stimulus , contract constraint, mutual competition combined with external govern-ance in our country.

  5. Alternating brittle and ductile response of coherent twin boundaries in nanotwinned metals

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, Tanushree; Kulkarni, Yashashree, E-mail: ykulkarni@uh.edu [Department of Mechanical Engineering, University of Houston, Houston, Texas 77204 (United States)

    2014-11-14

    Nanotwinned metals have opened exciting avenues for the design of high strength and high ductility materials. In this work, we investigate crack propagation along coherent twin boundaries in nanotwinned metals using molecular dynamics. Our simulations reveal that alternating twin boundaries exhibit intrinsic brittleness and ductility owing to the opposite crystallographic orientations of the adjoining twins. This is a startling consequence of the directional anisotropy of an atomically sharp crack along a twin boundary that favors cleavage in one direction and dislocation emission from the crack tip in the opposite direction. We further find that a blunt crack exhibits ductility in all cases albeit with very distinct deformation mechanisms and yield strength associated with intrinsically brittle and ductile coherent twin boundaries.

  6. Local and polycrystalline textures in BCC metals; their evolution and effect on mechanical response.

    Energy Technology Data Exchange (ETDEWEB)

    Bingert, J. F. (John F.); Henrie, B. L. (Benjamin Lyman); Cady, C. M. (Carl McElhinney); Gray, G. T. (George T.), III; Maudlin, P. J. (Paul J.)

    2004-01-01

    Texture development in BCC metals follows from the active deformation mechanisms and imposed strain path. Tensile, compressive, plane strain, and shear deformation induce different crystal rotations and thus resultant textures at both the macroscale and mesoscale. This work investigates the interaction of texture and bulk plasticity with regards to constitutive behavior, strain localization, and damage initiation in BCC metals. Tantalum and low-carbon steel were analyzed by electron backscatter diffraction to determine the crystallographic mesostructure, while mechanical testing was performed over a range of strain rates and temperatures. Polycrystal plasticity modeling was used to predict texture evolution for a suite of strain paths and to calculate multi-dimensional yield surfaces. The calculated yield surfaces were then applied to estimate texture effects on mechanical properties. Measuring the plastic anisotropy associated with experimental compression samples enabled validation of these simulations. The impact of relative slip system activity on anisotropic plasticity will also be explored.

  7. Assessment of Non-Revenue Water Situation in Mandalay City: Response to the Management of Sustainable Water Supply System in Mandalay City

    Directory of Open Access Journals (Sweden)

    Ser Moe Yi

    2017-07-01

    Full Text Available Mandalay city is experiencing inefficient use of groundwater resources and inadequate water supply system to residents. The study focused on the issue of non-revenue water (NRW and stakeholders’ perception on its management in order to design the remediation measures for the water lost controls and the sustainable water supply system. A total of 134 samples of water employees, and 383 households were assessed through structured questionnaires. It has been found that more than 50% of the water employees are not aware of the NRW concept. Furthermore, over 90% of the water users are not willing to participate in water management. The WB­EasyCalc software version 4.09 was used to determine NRW and the result of NRW is 46% of the total system input volume. The main causes of water losses in Mandalay city are: 1 a very low pressure system; 2 poor-quality repairs; 3 lack of regular maintenance; 4 water employees’ insufficient knowledge; 5 lack of awareness about the NRW concept; 6 poor customer relationships; and 7 water users’ lack of willingness to participate in the water losses management. Therefore, it is recommended that water utility service efficiency be optimized by giving capacity building to the water employees. It is also recommended that district metering areas (DMA be introduced and good customer relationship be established. This is to improve the water users’ willingness to participate in the water losses management for the efficient use under scarcity groundwater resources and for the sustainable water supply system.

  8. The response of metal clusters to q- and L-dependent external fields

    Energy Technology Data Exchange (ETDEWEB)

    Serra, Ll.; Garcias, F. (Universidad de las Islas Baleares, Palma de Mallorca (Spain). Dept. de Fisica); Barberan, N.; Barranco, M. (Barcelona Univ. (Spain). Dept. de Estructura y Constituyentes de la Materia); Navarro, J. (Valencia Univ. (Spain). Dept. de Fisica Atomica, Molecular y Nuclear Consejo Superior de Investigaciones Cientificas, Valencia (Spain). Inst. de Fisica Corpuscular); Rubio, A. (Valladolid Univ. (Spain). Dept. de Fisica Teorica, Atomica, Molecular y Nuclear)

    1991-01-01

    We have calculated the static polarizability and mean excitation energy of metal clusters submitted to q-and L-dependent external fields of j{sub L} (qr) Y{sub LO}({Omega}) type. Use has been made of an Extended Random-Phase Approximation which includes exchange and correlation effects within a local model, and of the spherical jellium model to describe the neutralizing positive background. (orig.).

  9. Supply Chain Management Practices in Toy Supply Chains

    DEFF Research Database (Denmark)

    Wong, Chee Yew; Arlbjørn, Jan Stentoft; Johansen, John

    2005-01-01

    Purpose - Innovative products usually experience highly unpredictable and variable demand. This is especially valid for the volatile and seasonal toy industry, which produces high obsolete inventory, lost sales and markdown. In such a volatile industry, what supply chain management (SCM) practices...... (traditional mass-production or push-models). These low-responsive practices in the toy supply chain are not caused only by slow knowledge diffusion. SCM know-how is not yet capable of managing such levels of volatility and seasonality. Therefore, explanations of these theoretical gaps and what new theories...... are applicable and effective? This study seeks to explore SCM practices, and identify practical and theoretical gaps in toy supply chains. Design/methodology/approach - This article includes a longitudinal and in-depth case study during the past year in an international toy manufacturer, which includes...

  10. Soil quality changes in response to their pollution by heavy metals, Georgia.

    Science.gov (United States)

    Matchavariani, Lia; Kalandadze, Besik; Lagidze, Lamzira; Gokhelashvili, Nino; Sulkhanishvili, Nino; Paichadze, Nino; Dvalashvili, Giorgi

    2015-01-01

    The present study deals with the composition, migration and accumulation of heavy metals in irrigated soils, plants and partially natural waters; and also, establishing the possible sources of pollution and their impact on environmental situation. The content of toxic elements in the irrigated soils adjacent to ore mining and processing enterprise were studied. Content of toxic elements in the irrigated soils adjacent to ore mining, showed that more than half of territory was seriously polluted by copper and zinc. Some part of the area were considered catastrophically polluted. Expressed technogenesis taking place influenced irrigation. Heavy metals like copper, zinc and manganese negative by effected the properties of soil, thus composition and soil-forming processes taking place in the soil. It was especially well represented in the deterioration of hydro-physical potential of the soil. Irrigation of agricultural land plots by water, polluted with heavy metals changed the pH. Balanced correlation among solid, liquid and gas phases was disrupted. In highly polluted soil, the cementing processes took place that sharply increased the bulk density of the soil, deteriorated the porosity of soil and reduced water permeability critically.

  11. Microbial ecological response of the intestinal flora of Peromyscus maniculatus and P. leucopus to heavy metal contamination.

    Science.gov (United States)

    Coolon, Joseph D; Jones, Kenneth L; Narayanan, Sanjeev; Wisely, Samantha M

    2010-03-01

    Heavy metal contamination negatively affects natural systems including plants, birds, fish and bacteria by reducing biodiversity at contaminated sites. At the Tri-State Mining District, efforts have been made to remediate sites to mitigate the detrimental effects that contamination has caused on human health. While the remediation effort has returned the site to within federal safety standards, it is unclear if this effort is sufficient to restore floral and faunal communities. Intrinsic to ecosystem and organism health is the biodiversity and composition of microbial communities. We have taken advantage of recent advances in sequencing technology and surveyed the bacterial community of remediated and reference soils as well as the intestinal microbial community of two ubiquitous rodent species to provide insight on the impacts of residual heavy metal contamination on the ecosystem. Rodents found on the remediated site had reduced body mass, smaller body size and lower body fat than animals on reference sites. Using bar-coded, massively parallel sequencing, we found that bacterial communities in both the soil and Peromyscus spp. gastrointestinal tracts had no difference in diversity between reference and remediated sites but assemblages differed in response to contamination. These results suggest that niche voids left by microbial taxa that were unable to deal with the remnant levels of heavy metals on remediated sites were replaced by taxa that could persist in this environment. Whether this replacement provided similar ecosystem services as ancestral bacterial communities is unknown.

  12. How Will Textile and Apparel Enterprises Construct a Quick-response Supply Chain%纺织服装业如何构建快速响应供应链

    Institute of Scientific and Technical Information of China (English)

    贺显伟

    2015-01-01

    纺织服装业"多品种""快时尚"发展趋势,要求企业具有快速响应型供应链与之匹配.本文从产品流、信息流及供应商分类、评估、选择、管理、集成等多角度阐述了纺织服装业如何构建快速响应供应链.%The textile and apparel industry is developing towards "diversified products" and "fast fashion", which requires enterprises to set up compatible quick-response supply chain. The paper discusses how to construct such supply chain from various perspectives including product flow and information flow as well as classification, evaluation, selection and integration of suppliers.

  13. Security of supply

    OpenAIRE

    2007-01-01

    Paul Isbell revisits the energy security debate; John Gault considers European security and natural gas supplies; William C. Ramsay discusses security of energy supplies in a global market; Hasan M. Qabazard outlines OPEC’s abiding commitment to energy security.

  14. Development Strategy on Supply Chain Promoted by Social Responsibility of Modern Enterprises%现代企业社会责任驱动的供应链发展策略研究

    Institute of Scientific and Technical Information of China (English)

    张凤荣; 张建平

    2011-01-01

    企业社会责任涵化和政策激励是驱动企业不断完善社会责任的动力。企业社会责任在供应链中的压力是不均匀的,可将供应链上的企业社会责任发展策略分为供应链前端的风险规避策略、供应链中端的核心优势策略和供应链后端的信息共享策略三种形式。现代企业的竞争是供应链的竞争,国际社会对中国企业社会责任关注的主要焦点是供应链。跨国企业主要受国际性标准影响,常常是购买方(国外大品牌)而不是政府管理者要求企业遵守劳动法,但从中长期来看,自愿性将逐步成为中国企业社会责任的发展趋势。%The acculturation and policy motivation of enterprise social responsibility is a force to drive the enterprise to improve its social responsibility. The pressure of enterprise social responsibility is uneven in supply chain. The strategies to develop enterprise social responsibility are that of risk avoidance in the front end of supply chain, core advantage in the middle end, and information sharing in the rear end. The competition of modem enterprise is supply chain, and foreign enterprises' focus on China's enterprise social responsibility is also the supply chain. Influenced by international standards, the multinational enterprises, usually the purchasers-some big foreign brands-not the administrators ask the enterprises to obey Labor Law. From a medium and long term development, initiative will become a trend of China's enterprise social responsibility.

  15. Response of dandelion (Taraxacum officinale Web) to heavy metals from mine sites: micromorphology of leaves and roots.

    Science.gov (United States)

    Bini, Claudio; Maleci, Laura; Buffa, Gabriella; Wahsha, Mohammad; Fontana, Silvia

    2013-04-01

    Response of dandelion (Taraxacum officinale Web) to heavy metals from mine sites: micromorphology of leaves and roots. Maleci L.1 , Bini C.2, Buffa G. 2, Fontana S2., Wahsha M.3 1 - Dept of Biology, University of Florence, Italy. 2 - Dept of Environmental Sciences, Informatics and Statistics. Ca'Foscari University, Venice - Italy. 3 - Marine Science Centre - University of Jordan, Aqaba section, Jordan. Heavy metal accumulation is known to produce significant physiological and biochemical responses in vascular plants. Yet, metabolic and physiological responses of plants to heavy metal concentration can be viewed as potentially adaptive changes of the plants during stress. From this point of view, plants growing on abandoned mine sites are of particular interest, since they are genetically tolerant to high metal concentrations, and can be utilized in soil restoration. Among wild plants, the common dandelion (Taraxacum officinale Web) has received attention as bioindicator plant, and has been also suggested in remediation projects. Wild specimens of Taraxacum officinale Web, with their soil clod, were gathered from three sites with different contamination levels by heavy metals (Cd, Cr, Cu, Fe, Pb, Zn) in the abandoned Imperina Valley mine (Northeast Italy). A control plant was also gathered from a not contaminated site nearby. Plants were cultivated in pots for one year at HBF, and appeared macroscopically not affected by toxic signals (reduced growth, leaf necrosis) possibly induced by soil HM concentration. Leaves and roots taken at the same growing season were observed by LM and TEM. Light microscopy observations carried out on the leaf lamina show a clear difference in the cellular organization of not-contaminated and contaminated samples. The unpolluted samples present a well organized palisade tissue and spongy photosynthetic parenchyma. Samples from contaminated sites, instead, present a palisade parenchyma less organized, and a reduction of leaf thickness

  16. Proposal for the Development of an Economic Operator's Socially Responsible Management, by Manufacturing Metallic Objects for the Children's Play, both Outdoors and Indoors

    Directory of Open Access Journals (Sweden)

    Potincu L.

    2014-12-01

    Full Text Available This scientific paper intends to practically approach aspects related to socially responsible management by relating it to the activity of an economic operator manufacturing metal objects. The development of the socially responsible management is approached in relation to the responsibilities which are part of the corporate social responsibility concept (CSR. Thus, in our research, we have especially used juridical analysis methods and juridical proposals (de lege ferenda proposals, but also several elements belonging to other research fields.

  17. Expression and characterization analysis of type 2 metallothionein from grey mangrove species (Avicennia marina) in response to metal stress

    Energy Technology Data Exchange (ETDEWEB)

    Huang Guoyong, E-mail: huang_gyh@sina.com [Key Laboratory of Tropical Marine Environmental Dynamics, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301 (China); State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Wang Youshao [Key Laboratory of Tropical Marine Environmental Dynamics, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301 (China)

    2010-08-01

    Metallothioneins (MTs) are a family of low-molecular-weight cysteine-rich proteins and are thought to play possible roles in metal metabolism or detoxification. To evaluate the roles of metallothioneins in metal homeostasis or tolerance in Avicennia marina, a real-time quantitative PCR protocol was developed to directly evaluate the expression of AmMT2 mRNA, when A. marina seedlings were exposed to different concentrations of zinc (Zn), copper (Cu) or lead (Pb) for 3 and 7 d. Real-time quantitative PCR results indicated that the regulation of AmMT2 mRNA expression by Zn, Cu and Pb was strongly dependent on concentration and time of exposure. A significant increase in the transcripts of AmMT2 gene was also found in response to Zn, Cu and Pb, at least under some experimental conditions. When AmMT2 was overexpressed in Escherichia coli BL21 as a carboxy-terminal extension of glutathione-S-transferase (GST), the transgenic bacteria showed an increased tolerance to Zn, Cu, Pb and Cd exposure as compared to control strains. Moreover, GST-AmMT2 was purified from E. coli cells grown in the presence of 400 {mu}M Zn, Cu, Pb or Cd. The purified GST-AmMT2 fusion protein could bind higher levels of all four metals than GST alone. Taken together, these data support the hypothesis that AmMT2 may be involved in processes of metal homeostasis or tolerance in A. marina.

  18. Extracytoplasmic function (ECF sigma factor σF is involved in Caulobacter crescentus response to heavy metal stress

    Directory of Open Access Journals (Sweden)

    Kohler Christian

    2012-09-01

    Full Text Available Abstract Background The α-proteobacterium Caulobacter crescentus inhabits low-nutrient environments and can tolerate certain levels of heavy metals in these sites. It has been reported that C. crescentus responds to exposure to various heavy metals by altering the expression of a large number of genes. Results In this work, we show that the ECF sigma factor σF is one of the regulatory proteins involved in the control of the transcriptional response to chromium and cadmium. Microarray experiments indicate that σF controls eight genes during chromium stress, most of which were previously described as induced by heavy metals. Surprisingly, σF itself is not strongly auto-regulated under metal stress conditions. Interestingly, σF-dependent genes are not induced in the presence of agents that generate reactive oxygen species. Promoter analyses revealed that a conserved σF-dependent sequence is located upstream of all genes of the σF regulon. In addition, we show that the second gene in the sigF operon acts as a negative regulator of σF function, and the encoded protein has been named NrsF (Negative regulator of sigma F. Substitution of two conserved cysteine residues (C131 and C181 in NrsF affects its ability to maintain the expression of σF-dependent genes at basal levels. Furthermore, we show that σF is released into the cytoplasm during chromium stress and in cells carrying point mutations in both conserved cysteines of the protein NrsF. Conclusion A possible mechanism for induction of the σF-dependent genes by chromium and cadmium is the inactivation of the putative anti-sigma factor NrsF, leading to the release of σF to bind RNA polymerase core and drive transcription of its regulon.

  19. Generating magnetic response and half-metallicity in GaP via dilute Ti-doping for spintronic applications

    Energy Technology Data Exchange (ETDEWEB)

    Saini, Hardev S. [Department of Physics, Panjab University, Chandigarh 160014 (India); Kashyap, Manish K., E-mail: manishdft@gmail.com [Department of Physics, Kurukshetra University, Kurukshetra 136119, Haryana (India); Kumar, Manoj [Department of Physics, Panjab University, Chandigarh 160014 (India); Kendriya Vidyalya No. 1, Kanchrapara, 743193 West Bengal (India); Thakur, Jyoti [Department of Physics, Kurukshetra University, Kurukshetra 136119, Haryana (India); Singh, Mukhtiyar [Department of Physics, Dyanand Postgraduate College, Hisar, 125001 Haryana (India); Reshak, Ali H. [New Technologies – Research Centre, University of West Bohemia, Univerzitni 8, 306 14 Pilsen (Czech Republic); Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis (Malaysia); Saini, G.S.S. [Department of Physics, Panjab University, Chandigarh 160014 (India)

    2015-11-15

    Existence of band gap in one spin channel and metallic character in other leads to interesting magnetic and optical properties of any material. These materials are capable to generate fully spin polarized current and are responsible for maximizing the efficiency of spintronic devices. The present work explores the electronic and magnetic properties of Ti-doped GaP compound with dopant concentrations; x = 0.02, 0.03 and 0.06 in order to search new Diluted Magnetic Semiconductor (DMS) compounds as spintronic materials using full potential linearized augmented plane wave plus local orbitals (FPLAPW + lo) method. The generalized gradient approximation (GGA) is used to decide exact exchange-correlation (XC) potentials. The calculated results showed that the total magnetic moment of ∼1.00 μ{sub B} gets induced after Ti-doping in GaP at all dopant concentrations, irrespective of any magnetic element present. Further, this doping also generates half-metallicity in GaP with a half-metallic (HM) gap at Fermi level (E{sub F}) in minority spin channel. The half metallicity is originated by the hybridization of Ti-d states with P–p states. This induced magnetism appeared in the systems is the result of exchange interactions between host (GaP) and Ti-atom. - Highlights: • Dilute doping of Ti in Gap is addressed to produce authenticate theoretical data. • Ti-doping generates band gap at Fermi level in minority spin channel. • Magnetism appeared is the result of exchange interactions between host (GaP) and Ti. • Magnetic moment remains constant within studied dopant concentrations.

  20. On robustness in food supply chain networks

    NARCIS (Netherlands)

    Vlajic, J.V.; Vorst, van der J.G.A.J.; Hendrix, E.M.T.

    2010-01-01

    Purpose: Today's business environment is characterized by challenges of strong global competition where companies tend to achieve leanness and maximum responsiveness to customer demand. Lean supply chain networks are vulnerable to all kind of disruptions. For food supply chain networks (FSCNs), due

  1. On robustness in food supply chain networks

    NARCIS (Netherlands)

    Vlajic, J.V.; Vorst, van der J.G.A.J.; Hendrix, E.M.T.

    2010-01-01

    Purpose: Today's business environment is characterized by challenges of strong global competition where companies tend to achieve leanness and maximum responsiveness to customer demand. Lean supply chain networks are vulnerable to all kind of disruptions. For food supply chain networks (FSCNs), due

  2. Transient Response of Organo-Metal-Halide Solar Cells Analyzed by Time-Resolved Current-Voltage Measurements

    Directory of Open Access Journals (Sweden)

    M. Greyson Christoforo

    2015-11-01

    Full Text Available The determination of the power conversion efficiency of solar cells based on organo-metal-halides is subject to an ongoing debate. As solar cell devices may exhibit very slow transient response, current-voltage scans in different directions may not be congruent, which is an effect often referred to as hysteresis. We here discuss time-resolved current-voltage measurements as a means to evaluate appropriate delay times (voltage settling times to be used in current-voltage measurements of solar cells. Furthermore, this method allows the analysis of transient current response to extract time constants that can be used to compare characteristic differences between devices of varying architecture types, selective contacts and changes in devices due to storage or degradation conditions.

  3. Evidence that bio-metallic mineral precipitation enhances the complex conductivity response at a hydrocarbon contaminated site

    Science.gov (United States)

    Mewafy, Farag M.; Werkema, D. Dale; Atekwana, Estella A.; Slater, Lee D.; Abdel Aal, Gamal; Revil, André; Ntarlagiannis, Dimitrios

    2013-11-01

    The complex conductivity signatures of a hydrocarbon contaminated site, undergoing biodegradation, near Bemidji, Minnesota were investigated. This site is characterized by a biogeochemical process where iron reduction is coupled with the oxidation of hydrocarbon contaminants. The biogeochemical transformations have resulted in precipitation of different bio-metallic iron mineral precipitates such as magnetite, ferroan calcite, and siderite. Our main objective was to elucidate the major factors controlling the complex conductivity response at the site. We acquired laboratory complex conductivity measurements along four cores retrieved from the site in the frequency range between 0.001 and 1000 Hz. Our results show the following: (1) in general higher imaginary conductivity was observed for samples from contaminated locations compared to samples from the uncontaminated location, (2) the imaginary conductivity for samples contaminated with residual and free phase hydrocarbon (smear zone) was higher compared to samples with dissolved phase hydrocarbon, (3) vadose zone samples located above locations with free phase hydrocarbon show higher imaginary conductivity magnitude compared to vadose zone samples from the dissolved phase and uncontaminated locations, (4) the real conductivity was generally elevated for samples from the contaminated locations, but not as diagnostic to the presence of contamination as the imaginary conductivity; (5) for most of the contaminated samples the imaginary conductivity data show a well-defined peak between 0.001 and 0.01 Hz, and (6) sample locations exhibiting higher imaginary conductivity are concomitant with locations having higher magnetic susceptibility. Controlled experiments indicate that variations in electrolytic conductivity and water content across the site are unlikely to fully account for the higher imaginary conductivity observed within the smear zone of contaminated locations. Instead, using magnetite as an example of the

  4. Who Manages Our Supply Chains?

    DEFF Research Database (Denmark)

    Flöthmann, Christoph

    to manage the manifold tasks they face on a daily basis. Unfortunately, as globalization has simultaneously increased the complexity of supply chains and the demand for highly qualified personnel, companies are facing a significant undersupply of talent (Cottrill, 2010). Moreover, organizations appear......While managers in traditional management functions focus on developing strong expertise to become “specialists” in their own discipline, supply chain managers are a different species: They have to combine a cross-functional understanding of various business fields and multi-faceted competencies...... to lack understanding of supply chain personnel and how to support their recruitment, succession planning, and training and development (John, 2015). Surprisingly, at the same time, scientific research on that topic is relatively scarce. In response, the overarching purpose of this paper...

  5. Who Manages Our Supply Chains?

    DEFF Research Database (Denmark)

    Flöthmann, Christoph

    to manage the manifold tasks they face on a daily basis. Unfortunately, as globalization has simultaneously increased the complexity of supply chains and the demand for highly qualified personnel, companies are facing a significant undersupply of talent (Cottrill, 2010). Moreover, organizations appear......While managers in traditional management functions focus on developing strong expertise to become “specialists” in their own discipline, supply chain managers are a different species: They have to combine a cross-functional understanding of various business fields and multi-faceted competencies...... to lack understanding of supply chain personnel and how to support their recruitment, succession planning, and training and development (John, 2015). Surprisingly, at the same time, scientific research on that topic is relatively scarce. In response, the overarching purpose of this paper...

  6. Transcriptional impact of organophosphate and metal mixtures on olfaction: copper dominates the chlorpyrifos-induced response in adult zebrafish.

    Science.gov (United States)

    Tilton, Fred A; Tilton, Susan C; Bammler, Theo K; Beyer, Richard P; Stapleton, Patricia L; Scholz, Nathaniel L; Gallagher, Evan P

    2011-04-01

    Chemical exposures in fish have been linked to loss of olfaction leading to an inability to detect predators and prey and decreased survival. However, the mechanisms underlying olfactory neurotoxicity are not well characterized, especially in environmental exposures which involve chemical mixtures. We used zebrafish to characterize olfactory transcriptional responses by two model olfactory inhibitors, the pesticide chlorpyrifos (CPF) and mixtures of CPF with the neurotoxic metal copper (Cu). Microarray analysis was performed on RNA from olfactory tissues of zebrafish exposed to CPF alone or to a mixture of CPF and Cu. Gene expression profiles were analyzed using principal component analysis and hierarchical clustering, whereas gene set analysis was used to identify biological themes in the microarray data. Microarray results were confirmed by real-time PCR on genes serving as potential biomarkers of olfactory injury. In addition, we mined our previously published Cu-induced zebrafish olfactory transcriptional response database (Tilton et al., 2008) for the purposes of discriminating pathways of olfaction impacted by either the individual agents or the CPF-Cu mixture transcriptional signatures. CPF exposure altered the expression of gene pathways associated with cellular morphogenesis and odorant binding, but not olfactory signal transduction, a known olfactory pathway for Cu. The mixture profiles shared genes from the Cu and CPF datasets, whereas some genes were altered only by the mixtures. The transcriptional signature of the mixtures was more similar to that in zebrafish exposed to Cu alone than for CPF. In conclusion, exposure to a mixture containing a common environmental metal and pesticide causes a unique transcriptional signature that is heavily influenced by the metal, even when organophosphate predominates.

  7. Effect of fly ash application on soil microbial response and heavy metal accumulation in soil and rice plant.

    Science.gov (United States)

    Nayak, A K; Raja, R; Rao, K S; Shukla, A K; Mohanty, Sangita; Shahid, Mohammad; Tripathi, R; Panda, B B; Bhattacharyya, P; Kumar, Anjani; Lal, B; Sethi, S K; Puri, C; Nayak, D; Swain, C K

    2015-04-01

    Fly ash (FA), a byproduct of coal combustion in thermal power plants, has been considered as a problematic solid waste and its safe disposal is a cause of concern. Several studies proposed that FA can be used as a soil additive; however its effect on microbial response, soil enzymatic activities and heavy metal accumulation in soil and grain of rice (cv. Naveen) to fly ash (FA) application was studied in a pot experiment during dry season 2011 in an Inceptisol. Fly ash was applied at a rate of zero per cent (FS), five per cent (FA5), ten per cent (FA10), twenty per cent (FA20), 40 per cent (FA40) and 100 per cent (FA100) on soil volume basis with nitrogen (N), phosphorus (P) and potassium (K) (40:20:20mg N:P:Kkg(-1) soil) with six replications. Heavy metals contents in soil and plant parts were analysed after harvest of crop. On the other hand, microbial population and soil enzymatic activities were analysed at panicle initiation stage (PI, 65 days after transplanting) of rice. There was no significant change in the concentration of zinc (Zn), iron (Fe), copper (Cu), manganese (Mn), cadmium (Cd) and chromium (Cr) with application of fly ash up to FA10. However, at FA100 there was significant increase of all metals concentration in soil than other treatments. Microorganisms differed in their response to the rate of FA application. Population of both fungi and actinomycetes decreased with the application of fly ash, while aerobic heterotrophic bacterial population did not change significantly up to FA40. On the other hand, total microbial activity measured in terms of Fluorescein diacetate (FDA) assay, and denitrifiers showed an increased trend up to FA40. However, activities of both alkaline and acid phosphatase were decreased with the application of FA. Application of FA at lower levels (ten to twenty per cent on soil volume basis) in soil enhanced micronutrients content, microbial activities and crop yield.

  8. Coordination polymer nanocapsules prepared using metal-organic framework templates for pH-responsive drug delivery

    Science.gov (United States)

    Tang, Lei; Shi, Jiafu; Wang, Xiaoli; Zhang, Shaohua; Wu, Hong; Sun, Hongfan; Jiang, Zhongyi

    2017-07-01

    A facile, efficient, and versatile approach is presented to synthesize pH-responsive nanocapsules (˜120 nm) by combining the advantages of metal-organic frameworks (MOFs) and metal-organic thin films. ZIF-8 nanoparticles are used as templates on which a thin film coating of iron(III)-catechol complexes is derived from the coordination between dopamine-modified alginate (AlgDA) and iron(III) ions. After the template removal, nanocapsules with a pH-responsive wall are obtained. Doxorubicin (Dox), a typical anticancer drug, is first immobilized in ZIF-8 frameworks through coprecipitation and then encapsulated in nanocapsules after the removal of ZIF-8. The structure of the iron(III)-catechol complex varies with pH value, thus conferring the Dox@Nanocapsules with tailored release behavior in vitro. Cytotoxicity tests illustrate the highly effective cytotoxicity of Dox@Nanocapsules towards cancer cells. This study provides a new method for preparing smart nanocapsules and offers more opportunities for the controlled delivery of drugs.

  9. Instabilities in the optical response of a semiconductor quantum dot—metal nanoparticle heterodimer: self-oscillations and chaos

    Science.gov (United States)

    Nugroho, Bintoro S.; Iskandar, Alexander A.; Malyshev, Victor A.; Knoester, Jasper

    2017-01-01

    We theoretically investigate the nonlinear optical response of a heterodimer comprising a semiconductor quantum dot strongly coupled to a metal nanoparticle. The quantum dot is considered as a three-level ladder system with ground, one-exciton, and bi-exction states. As compared to the case of a two-level quantum dot model, adding the third (bi-exciton) state produces fascinating effects in the optical response of the hybrid system. Specifically, we demonstrate that the system may exhibit picosecond and sub-picosecond self-oscillations and quasi-chaotic behaviour under single-frequency continuous wave excitation. An isolated semiconductor quantum dot does not show such features. The effects originate from competing one-exciton and bi-exciton transitions in the semiconductor quantum dot, triggered by the self-action of the quantum dot via the metal nanoparticle. The key parameter that governs the phenomena mentioned is the ratio of the self-action strength and the bi-exciton shift. The self-oscillation regime can be achieved in practice, in particular, in a heterodimer comprised of a closely spaced ZnS/ZnSe core-shell quantum dot and a spherical silver nanoparticle. The results may have applications in nanodevices for generating trains of ultrashort optical pulses.

  10. Driving Forces and Equilibrium Analysis of Social Responsibility in Marine Aquatic Products Supply Chain%海洋水产品供应链社会责任驱动力和平衡分析

    Institute of Scientific and Technical Information of China (English)

    姜启军; 胡珂

    2016-01-01

    Food safety,food information transparency,environmental pollution,ecological destruc-tion,climate change and other issues are the crucial problems of corporate social responsibility in marine aquatic products supply chain,but have been ignored for a long time.Aquaculture is pros-perous in China.In recent years,the safety issues of China’ s marine aquaculture emerge all the time,such as excessive drug residues in breeding section,unstandardized operation in processing stages and the abuse of preservatives in the transport and storage process,etc..These have caused serious damage to consumers’ health.It is precisely because of the lack of the driving force in per-forming the social responsibility of member enterprises in marine aquatic products supply chain, which has led to frequent safety problems of aquatic products.This paper argued that the driving force of CSR (corporate social responsibility)came from the core enterprise in the food supply chain,and the pressure about CSR was different between large enterprises and small and medium-sized enterprise in the whole supply chain.The imbalance of market power in supply chain would have an adverse effect on CSR’ s performance for small and medium-sized food enterprises,and in-duced CSR clashes between supply chain members.A relative balance situation about CSR of the enterprises in the supply chain was needed to be achieved to obtain stability in the supply chain.%食品安全、食品信息透明度、海洋环境污染、生态破坏、气候变化等是海洋水产品供应链社会责任的主要问题,但长期被我们忽视。中国是水产养殖大国,近年来我国海洋水产品供应链中食品安全问题层出不穷,如养殖环节药残超标、加工环节操作不规范、仓储与运输过程中滥用防腐剂等,严重损害消费者的身心健康。正是由于水产品供应链中的成员企业缺少履行社会责任的驱动力,才导致水产品安全问题频发。文章

  11. Enhanced magnetic response and metallicity in AB stacked bilayer graphene via Cr-doping

    Energy Technology Data Exchange (ETDEWEB)

    Thakur, Jyoti [Department of Physics, Kurukshetra University, Kurukshetra 136119, Haryana (India); Kashyap, Manish K., E-mail: manishdft@gmail.com [Department of Physics, Kurukshetra University, Kurukshetra 136119, Haryana (India); Saini, Hardev S. [Department of Physics, Panjab University, Chandigarh 160014 (India); Reshak, Ali H. [New Technologies – Research Centre, University of West Bohemia, Univerzitni 8, 306 14 Pilsen (Czech Republic); Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis (Malaysia)

    2015-11-15

    First-principles study for the electronic and magnetic properties of Cr atom doping in lower layer of AB bernal stacked bilayer graphene (BLG) is presented. This doping is analysed in three different configurations; (i) Hollow type (above the centre of C hexagon), (ii) Top-type (directly on the top of any C atom) and (iii) Bridge type (mid point of any C–C bond). It has been observed that the doping of Cr atom enlarges the interlayer spacing in BLG as compared to pure one. The Top-type (T-type) doping is found to be most stable energetically. The doping of Cr atom in all configurations generates the large spin polarization and induces the appreciable magnetic moment. Half metallicity has been obtained in Hollow type (H-type) doping with a suitable band gap of 0.28 eV in minority spin channel. The origin of magnetism has been identified via interactions of 3d-states of doped Cr atom with p-states of inequivalent C atoms present in the vicinity of doping site. The electron densities plots also confirm the metallic nature of Cr-doped BLG. Our results reveal that the resultant BLG has potential for futuristic applications such as high frequency transistors, spintronics, photodetectors and energy resources. - Highlights: • Cr-doping in bilayer graphene induces magnetic channel. • Half metallicity is observed only in H-type Cr-doping in graphene. • T-type doping is most energetically stable among all types (H-type, B-type and T-type). • The strong hybridization of Cr-3d states with C-p states governs the magnetism in BLG.

  12. GROWTH RESPONSE OF THE DUCKWEED LEMNA MINOR TO HEAVY METAL POLLUTION

    OpenAIRE

    2009-01-01

    To assess the tolerance and effect of heavy metals pollution on the duckweed Lemna minor, the aquatic plants were exposed to different concentrations of copper (Cu), nickel (Ni), cadmium (Cd) and zinc (Zn) in a quarter Coïc and Lessaint solution at pH = 6.1 (± 0.1) and under a daily regime of 16 h light (101 μmol/m2.s1). Copper at 0.2 mg/L and nickel at 0.5 mg/L promoted the growth of Lemna fronds. At higher concentrations, Cu and Ni inhibited the growth of duckweed; the EC50 (concentration c...

  13. Enhancement and Inhibition of Transmission from metal gratings: Engineering the Spectral Response

    CERN Document Server

    de Ceglia, D; Scalora, M; Akozbek, N; Bloemer, M J

    2010-01-01

    We present a systematic analysis of the optical properties of slit arrays in metal films. An exhaustive investigation of geometrical and dispersive properties reveals the resonance features of these structures, including the role of surface waves and their relationship with features in the transmission spectrum. Although enhanced transmission windows are significantly dominated by the longitudinal resonances localized inside the slits, the periodicity introduces transverse resonances that can either enhance or inhibit light transmission. We thus illustrate the intriguing interaction regime between longitudinal and transverse resonances, where the two modes hybridize leading to the formation of a photonic band gap spectrum.

  14. Supply chain optimization for pediatric perioperative departments.

    Science.gov (United States)

    Davis, Janice L; Doyle, Robert

    2011-09-01

    Economic challenges compel pediatric perioperative departments to reduce nonlabor supply costs while maintaining the quality of patient care. Optimization of the supply chain introduces a framework for decision making that drives fiscally responsible decisions. The cost-effective supply chain is driven by implementing a value analysis process for product selection, being mindful of product sourcing decisions to reduce supply expense, creating logistical efficiency that will eliminate redundant processes, and managing inventory to ensure product availability. The value analysis approach is an analytical methodology for product selection that involves product evaluation and recommendation based on consideration of clinical benefit, overall financial impact, and revenue implications.

  15. GROWTH RESPONSE OF THE DUCKWEED LEMNA MINOR TO HEAVY METAL POLLUTION

    Directory of Open Access Journals (Sweden)

    N. Khellaf ، M. Zerdaoui

    2009-07-01

    Full Text Available To assess the tolerance and effect of heavy metals pollution on the duckweed Lemna minor, the aquatic plants were exposed to different concentrations of copper (Cu, nickel (Ni, cadmium (Cd and zinc (Zn in a quarter Coïc and Lessaint solution at pH = 6.1 (± 0.1 and under a daily regime of 16 h light (101 μmol/m2.s1. Copper at 0.2 mg/L and nickel at 0.5 mg/L promoted the growth of Lemna fronds. At higher concentrations, Cu and Ni inhibited the growth of duckweed; the EC50 (concentration causing 50% inhibition were 0.47 mg/L for Cu and 1.29 mg/L for Ni. Cadmium and zinc decreased by 50% the growth of fronds when the medium contained respectively 0.64 and 5.64 mg/L (EC50. Duckweed tolerated Cu, Ni, Cd and Zn at concentrations of 0.4, 3.0, 0.4 and 15.0 mg/L respectively without showing any visible signs of toxicity (chlorosis, frond disconnection and necrosis. On the basis of visible symptoms and the EC50 values, the toxicity of the metals on Lemna. minor was in decreasing order of damage: Cu > Cd > Ni > Zn. It was concluded that the duckweed Lemna. minor is very sensitive to copper and cadmium pollution.

  16. Giant anisotropic nonlinear optical response in transition metal monopnictide Weyl semimetals

    CERN Document Server

    Wu, Liang; Morimoto, Takahiro; Nair, Nityan L; Thewalt, Eric; Little, Arielle; Analytis, James G; Moore, Joel E; Orenstein, J

    2016-01-01

    Although Weyl fermions have proven elusive in high-energy physics, their existence as emergent quasiparticles was recently predicted in certain crystalline solids in which either inversion or time-reversal symmetry is broken\\cite{WanPRB2011,BurkovPRL2011, WengPRX2015,HuangNatComm2015}. The subsequent search for Weyl fermions in condensed matter soon led to their detection\\cite{XuScience2015, LvPRX2015, YangNatPhys2015} in transition metal monopnictides (TMMPs) such as TaAs, a class of noncentrosymmetric materials that heretofore received only limited attention. Now that the Weyl semimetal state in TMMPs is confirmed, the question arises as to whether these materials will exhibit novel, enhanced, or technologically applicable electronic properties. The TMMPs are polar metals, a rare subset of inversion-breaking crystals that would allow spontaneous polarization, were it not screened by conduction electrons\\cite{anderson1965symmetry,shi2013ferroelectric,kim2016polar}. Despite the absence of spontaneous polariza...

  17. Effect of temperature and season on reproduction, neutral red retention and metallothionein responses of earthworms exposed to metals in field soils

    Energy Technology Data Exchange (ETDEWEB)

    Svendsen, Claus [Centre for Ecology and Hydrology, Monks Wood, Abbots Ripton, Huntingdon, Cambridgeshire PE28 2LS (United Kingdom)]. E-mail: csv@ceh.ac.uk; Hankard, Peter K. [Centre for Ecology and Hydrology, Monks Wood, Abbots Ripton, Huntingdon, Cambridgeshire PE28 2LS (United Kingdom)]. E-mail: pkh@ceh.ac.uk; Lister, Lindsay J. [Centre for Ecology and Hydrology, Monks Wood, Abbots Ripton, Huntingdon, Cambridgeshire PE28 2LS (United Kingdom)]. E-mail: llist@ceh.ac.uk; Fishwick, Samantha K. [Environment Agency, Block 1 Government Buildings, Burghill Road, Westbury-on-Trym, Bristol BS10 6BF (United Kingdom)]. E-mail: samantha.fishwick@environment-agency.gov.uk; Jonker, Martijs J. [Centre for Ecology and Hydrology, Monks Wood, Abbots Ripton, Huntingdon, Cambridgeshire PE28 2LS (United Kingdom)]. E-mail: mjonker@science.uva.nl; Spurgeon, David J. [Centre for Ecology and Hydrology, Monks Wood, Abbots Ripton, Huntingdon, Cambridgeshire PE28 2LS (United Kingdom)]. E-mail: dasp@ceh.ac.uk

    2007-05-15

    This study investigated the short-term survival, reproduction and physiological (lysosomal membrane stability, metallothionein transcript copy number, body tissue metal concentrations) responses of Lumbricus rubellus exposed to metal contaminated field soils under different laboratory temperatures (10, 15 and 20 {sup o}C) and physiological responses of earthworms collected from the field in three different seasons (spring, autumn, winter). In the laboratory, metal contaminated soils had significant effects on reproduction (p < 0.001), metallothionein-2 (MT-2) expression (p = 0.033) and earthworm As (p = 0.003), Cd (p = 0.001), Pb (p < 0.001) and Zn (p < 0.001) concentration, but not lysosomal membrane stability and tissue Hg and Cu. No effect of temperature was found for any parameter. Principal component analysis of extractable and tissue metal concentrations indicated PC1 as a measure of metal stress. Both cocoon production (r = - 0.75) and MT-2 induction (r = 0.41) were correlated with PC1. A correlation was also found between cocoon production and MT-2 expression (r = - 0.41). Neutral red retention and MT-2 measurements in worms collected from the field sites in three seasons confirmed the absence of a temperature effect on these responses. - Laboratory and field studies demonstrate metal effects on earthworm life-cycle and biochemical responses are not influenced by temperature regime.

  18. The Concept Connotation of Supply Chain Social Responsibility and its Dynamic Mechanism%供应链社会责任的概念内涵与动力机制

    Institute of Scientific and Technical Information of China (English)

    陈远高

    2015-01-01

    Based on the related literature reviews and typical case studies, the possible reasons of the principal transition of the social responsibility from enterprise to supply chain are summarized, which consist of external environment, internal cooperation and systematic sustainable development. The new concept of Supply Chain Social Responsibility(SCSR)and analysis of connotation is presented. The characteristics of SCSR are also indicated as domination of core members, externality among members and asymmetry between responsibility and revenue. Furthermore, following the system analysis on cooperate social responsibility, sustainable supply chain and green supply chain, the dynamic mechanism of SCSR depicted by five forces integration of policy enforcement, public pressure, competition direction, demand-pull and supply chain restriction is developed. Finally, the conclusion and future direction of this research is discussed. This research extends the scope of cooperate social responsibility and provides the feasible suggestions for supply chain sustainable development and systematic promotion of social responsibility.%文章基于文献研究和典型案例分析,从供应链外部环境、内部合作与系统可持续发展三个方面总结了社会责任主体发生变迁的原因,进而提出了供应链社会责任这一概念,并阐释了供应链社会责任的内涵,指出了供应链社会责任的核心企业主导、链间外部性以及责任收益不对称的三大特点,通过系统分析企业社会责任、可持续供应链和绿色供应链等相关理论对企业承担社会责任动力机制的研究,提出了公共政策强制力、社会公众压力、市场竞争驱动力、需求拉动力以及供应链内部约束力等五力集成的供应链社会责任动力机制模型,最后进行了研究总结并指出了未来研究的方向。文章的研究拓展了企业社会责任研究的范畴,对供应链系统的可持续发

  19. Supply regimes in fisheries

    DEFF Research Database (Denmark)

    Nielsen, Max

    2006-01-01

    Supply in fisheries is traditionally known for its backward bending nature, owing to externalities in production. Such a supply regime, however, exist only for pure open access fisheries. Since most fisheries worldwide are neither pure open access, nor optimally managed, rather between the extremes......-economic supply model with mesh sizes is developed. It is found that in the presence of realistic management schemes, the supply curves are close to vertical in the relevant range. Also, the supply curve under open access with mesh size limitations is almost vertical in the relevant range, owing to constant...... recruitment. The implications are that the effects on supply following from e.g. trade liberalisation and reductions of subsidies are small in several and probably most fisheries worldwide. Keywords: backward-bending supply, regulated open access, regulated restricted access, mesh size regulation, Beverton...

  20. 组长负责制在消毒供应中心环节质量控制中的作用%Role of Group Leader Responsibility System in Link Quality Control of Central Sterile Supply Department

    Institute of Scientific and Technical Information of China (English)

    江楠; 李璟; 张帆

    2016-01-01

    Objective to analyze the leader responsibility system in disinfection supply center (CSSD) in the role of quality control. Methods the implementation of team leader responsibility system in disinfection supply center in our hospital, according to the division of the District, compared before and after the implementation of department satisfaction. Results after the implementation of the implementation of the satisfaction was significantly higher than before the implementation, the significant difference between the groups was statistically significant (P< 0.05). Conclusion the leader responsibility system should be used in the quality control of the central sterile supply center, which can significantly improve the quality of work, it is worthy of clinical choice and further promotion.%目的:分析组长负责制在消毒供应中心(CSSD)环节质量控制中的作用。方法在我院消毒供应中心实施组长责任制,进行按区划分,比较实施前后科室满意度情况。结果实施后科室满意度明显高于实施前,组间显著性差异具有统计学意义(P<0.05)。结论组长负责制应用于消毒供应中心环节质量控制工作中,可显著提高工作质量,值得临床选择和进一步推广。

  1. Effect of Water Vapor and Surface Morphology on the Low Temperature Response of Metal Oxide Semiconductor Gas Sensors

    Directory of Open Access Journals (Sweden)

    Konrad Maier

    2015-09-01

    Full Text Available In this work the low temperature response of metal oxide semiconductor gas sensors is analyzed. Important characteristics of this low-temperature response are a pronounced selectivity to acid- and base-forming gases and a large disparity of response and recovery time constants which often leads to an integrator-type of gas response. We show that this kind of sensor performance is related to the trend of semiconductor gas sensors to adsorb water vapor in multi-layer form and that this ability is sensitively influenced by the surface morphology. In particular we show that surface roughness in the nanometer range enhances desorption of water from multi-layer adsorbates, enabling them to respond more swiftly to changes in the ambient humidity. Further experiments reveal that reactive gases, such as NO2 and NH3, which are easily absorbed in the water adsorbate layers, are more easily exchanged across the liquid/air interface when the humidity in the ambient air is high.

  2. Thermo-responsive PNIPAM-metal hybrids: An efficient nanocatalyst for the reduction of 4-nitrophenol

    Science.gov (United States)

    Satapathy, Smith Sagar; Bhol, Prachi; Chakkarambath, Aswathy; Mohanta, Jagdeep; Samantaray, Kunal; Bhat, Suresh K.; Panda, Subhendu K.; Mohanty, Priti S.; Si, Satyabrata

    2017-10-01

    Micron size thermoresponsive cross-linked polymeric microgels of poly(N-isopropylacrylamide) (PNIPAM) are used as ;microreactor; for embedding metal nanoparticles of different shapes. Using a simple and robust method, we have synthesized various polymer-metal hybrid nanostructures incorporated with Au nanorods (AuNR), Au nanospheres (AuNS) and Ag nanospheres (AgNS). These hybrid nanostructures have been characterized by transmission electron microscope (TEM), UV-vis spectroscopy, dynamic light scattering (DLS) and static light scattering (SLS) followed by their catalytic activity. TEM studies directly confirmed the mondispersity of synthesized hybrid microgels and stability of the embedded metal nanoparticles within the microgels. Optical studies confirmed the presence of respective absorption bands that correspond to AuNS, AgNS and AuNR respectively. Extensive DLS studies demonstrated that although these hybrid microgels preserve their thermoresponsive properties, i.e their hydrodynamic radius decreased with increasing temperature, their thermosensitivity were comparatively lesser than pure PNIPAM microgels. Combining with studies using static light scattering, we further found that AuNS and AgNS were inhomogeneously distributed within microgels where the majority of the nanoparticles present within the loosely cross-linked shell. On the other hand AuNR were distributed more homogeneously within the microgels. Catalytic performance of various nanostructures loaded onto PNIPAM microgel beads were evaluated by studying the catalytic reduction of 4-nitrophenol. Complete catalytic conversion using AgNS occurred in ∼30 min with a first-order rate constant of 0.159 min-1 having a 7 min induction period. On the other hand no induction period was observed for AuNS and AuNR and the reaction completed in 3-4 min with a first-order rate constant of 1.607 min-1 and 1.627 min-1 respectively. Further, PNIPAM-AuNS and PNIPAM-AuNR possess better catalytic activity as well as

  3. Hybrid metal-dielectric ring resonators for homogenizable optical metamaterials with strong magnetic response at short wavelengths down to the ultraviolet range.

    Science.gov (United States)

    Tang, Jianwei; He, Sailing

    2013-10-07

    We derive an analytical LC model from Maxwell's equations for the magnetic resonance of subwavelength ring resonators. Using the LC model, we revisit the scaling of split-ring resonators. Inspired by the LC model, we propose a hybrid metal-dielectric ring resonator mainly composed of high index dielectric material (e.g., TiO₂) with some gaps filled with metal (e.g., Ag). The saturation frequency of magnetic response for the hybrid metal-dielectric ring resonator is much higher (up to the ultraviolet range) than that for split-ring resonators, and can be controlled by the metal fraction in the ring. The hybrid metal-dielectric ring resonator can also overcome the homogenization problem of all-dielectric magnetic resonators, and therefore can form homogenizable magnetic metamaterials at short wavelengths down to the ultraviolet range.

  4. Gold ions bio-released from metallic gold particles reduce inflammation and apoptosis and increase the regenerative responses in focal brain injury

    DEFF Research Database (Denmark)

    Larsen, Agnete; Kolind, Kristian; Pedersen, Dan Sonne

    2008-01-01

    neural stem cell response. We conclude that bio-liberated gold ions possess pronounced anti-inflammatory and neuron-protective capacities in the brain and suggest that metallic gold has clinical potentials. Intra-cerebral application of metallic gold as a pharmaceutical source of gold ions represents......Traumatic brain injury results in loss of neurons caused as much by the resulting neuroinflammation as by the injury. Gold salts are known to be immunosuppressive, but their use are limited by nephrotoxicity. However, as we have proven that implants of pure metallic gold release gold ions which do...... not spread in the body, but are taken up by cells near the implant, we hypothesize that metallic gold could reduce local neuroinflammation in a safe way. Bio-liberation, or dissolucytosis, of gold ions from metallic gold surfaces requires the presence of disolycytes i.e. macrophages and the process...

  5. Optics Supply Planning System

    Energy Technology Data Exchange (ETDEWEB)

    Gaylord, J

    2009-04-30

    The purpose of this study is to specify the design for an initial optics supply planning system for NIF, and to present quality assurance and test plans for the construction of the system as specified. The National Ignition Facility (NIF) is a large laser facility that is just starting operations. Thousands of specialized optics are required to operate the laser, and must be exchanged over time based on the laser shot plan and predictions of damage. Careful planning and tracking of optic exchanges is necessary because of the tight inventory of spare optics, and the long lead times for optics procurements and production changes. Automated inventory forecasting and production planning tools are required to replace existing manual processes. The optics groups members who are expected to use the supply planning system are the stakeholders for this project, and are divided into three groups. Each of these groups participated in a requirements specification that was used to develop this design. (1) Optics Management--These are the top level stakeholdersk, and the final decision makers. This group is the interface to shot operations, is ultimately responsible for optics supply, and decides which exchanges will be made. (2) Work Center Managers--This group manages the on site optics processing work centers. They schedule the daily work center operations, and are responsible for developing long term processing, equipment, and staffing plans. (3) Component Engineers--This group manages the vendor contracts for the manufacture of new optics and the off site rework of existing optics. They are responsible for sourcing vendors, negotiating contracts, and managing vendor processes. The scope of this analysis is to describe the structure and design details of a system that will meet all requirements that were described by stakeholders and documented in the analysis model for this project. The design specifies the architecture, components, interfaces, and data stores of the system

  6. Debugging on High-voltage Power Supply,Focusing Power Supply and Magnetic Field Power Supply

    Institute of Scientific and Technical Information of China (English)

    TU; Rui

    2015-01-01

    High-voltage power supply,focusing power supply and magnetic field power supply are the main parts of the power supply system of the EMIS(Electro-Magnetic Isotope Separator)supplying the ion source.In 2015,a high-voltage power supply,power supply for focusing and

  7. Nematode response to metal, PAHs and organic enrichment in tourist marinas of the Mediterranean Sea.

    Science.gov (United States)

    Moreno, M; Albertelli, G; Fabiano, M

    2009-08-01

    The structure of nematode assemblages was investigated in the sediments of two different tourist marinas in the Mediterranean Sea and related to pollution variables. Nematode densities and generic compositions were determined, as were concentrations of heavy metals, PAHs and organic matter. Results showed different assemblages at the two marinas, with a dominance of the genera Paralongicyatholaimus and Daptonema. Significant correlations between nematodes and concentrations of environmental contaminants were found. In particular, Paralongicyatholaimus showed a significant negative correlation with Cu concentrations and was almost absent at the stations where higher Cu concentrations were found. The presence of sensitive/tolerant nematode genera represents a promising tool to identify areas subjected to a higher level of disturbance and to define the correct environmental management strategy for harbors.

  8. Theoretical and experimental investigations on linear and nonlinear optical response of metal complexes doped PMMA films

    Science.gov (United States)

    Praveen, P. A.; Babu, R. Ramesh; Ramamurthi, K.

    2017-02-01

    Metal organic complexes, diaceto bis benzimidazole cobalt(II) and diaceto bis benzimidazole copper(II), are synthesized by a simple chemical route. The synthesized powders are doped in PMMA with 1, 3, 5 wt% and deposited as free standing films of thickness  ∼1 μm. For theoretical simulation, metal organic complex (MOC) embedded into the PMMA matrix is subjected to polarizability and hyperpolarizability calculations using the PM6 algorithm in MOPAC2012 package. It is found that the minimum interaction distance between PMMA and MOC is about 34 nm and does not vary with respect to the dopant. The copper complex shows higher interaction energy with the polymer matrix than the cobalt complex. Time dependent Hartree Fock approach is used to calculate the α, β and γ values for static, 0.25 and 0.5 eV energies; the cobalt complex shows higher polarizability and hyperpolarizability than the copper complex. Experimentally, the optical absorption, thermo-optic coefficient, nonlinear absorption coefficient and nonlinear refractive index of the samples are determined. The thermo-optic coefficients of the samples are seen to increase with increasing dopant concentration. From open aperture Z-scan studies the films are found to exhibit reverse saturable absorption behaviour, and from the closed aperture Z-scan all samples are found to exhibit self-focusing effects. The calculated third order susceptibility is in the order of 10‑5 esu. The optical limiting properties are studied at 650 nm using a 20 mW laser and all the samples are found to exhibit good optical limiting in the operating wavelength.

  9. Supply chain reliability modelling

    Directory of Open Access Journals (Sweden)

    Eugen Zaitsev

    2012-03-01

    Full Text Available Background: Today it is virtually impossible to operate alone on the international level in the logistics business. This promotes the establishment and development of new integrated business entities - logistic operators. However, such cooperation within a supply chain creates also many problems related to the supply chain reliability as well as the optimization of the supplies planning. The aim of this paper was to develop and formulate the mathematical model and algorithms to find the optimum plan of supplies by using economic criterion and the model for the probability evaluating of non-failure operation of supply chain. Methods: The mathematical model and algorithms to find the optimum plan of supplies were developed and formulated by using economic criterion and the model for the probability evaluating of non-failure operation of supply chain. Results and conclusions: The problem of ensuring failure-free performance of goods supply channel analyzed in the paper is characteristic of distributed network systems that make active use of business process outsourcing technologies. The complex planning problem occurring in such systems that requires taking into account the consumer's requirements for failure-free performance in terms of supply volumes and correctness can be reduced to a relatively simple linear programming problem through logical analysis of the structures. The sequence of the operations, which should be taken into account during the process of the supply planning with the supplier's functional reliability, was presented.

  10. Cobalt-alloy implant debris induce HIF-1α hypoxia associated responses: a mechanism for