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Sample records for in-line uranium immunosensor

  1. Final Technical Report - In-line Uranium Immunosensor

    International Nuclear Information System (INIS)

    Blake, Diane A.

    2006-01-01

    In this project, personnel at Tulane University and Sapidyne Instruments Inc. developed an in-line uranium immunosensor that could be used to determine the efficacy of specific in situ biostimulation approaches. This sensor was designed to operate autonomously over relatively long periods of time (2-10 days) and was able to provide near real-time data about uranium immobilization in the absence of personnel at the site of the biostimulation experiments. An alpha prototype of the in-line immmunosensor was delivered from Sapidyne Instruments to Tulane University in December of 2002 and a beta prototype was delivered in November of 2003. The beta prototype of this instrument (now available commercially from Sapidyne Instruments) was programmed to autonomously dilute standard uranium to final concentrations of 2.5 to 100 nM (0.6 to 24 ppb) in buffer containing a fluorescently labeled anti-uranium antibody and the uranium chelator, 2,9-dicarboxyl-1,10-phenanthroline. The assay limit of detection for hexavalent uranium was 5.8 nM or 1.38 ppb. This limit of detection is well below the drinking water standard of 30 ppb recently promulgated by the EPA. The assay showed excellent precision; the coefficients of variation (CV's) in the linear range of the assay were less than 5% and CV?s never rose above 14%. Analytical recovery in the immunosensors-based assay was assessed by adding variable known quantities of uranium to purified water samples. A quantitative recovery (93.75% - 108.17%) was obtained for sample with concentrations from 7.5 to 20 nM (2-4.75 ppb). In August of 2005 the sensor was transported to Oak Ridge National Laboratory, for testing of water samples at the Criddle test site (see Wu et al., Environ. Sci. Technol. 40:3978-3985 2006 for a description of this site). In this first on-site test, the in-line sensor was able to accurately detect changes in the concentrations of uranium in effluent samples from this site. Although the absolute values for the uranium

  2. Field-portable and automated immunosensors for hexavalent uranium, other heavy metals and chelators. Final Report

    International Nuclear Information System (INIS)

    Blake, Diane A.

    2009-01-01

    This is the final technical report for this 10-year project. A better understanding of in situ bioremediation processes and the development of strategies to enhance bacterial remediation of contaminated sites depend either directly or indirectly upon accurate detection and measurement of organics, metal and other toxic elements prior to, during and following the remediation process. Detection and measurement costs are presently high due to the complex methodologies required for analysis. Remediation costs could be significantly reduced through the use of rapid, simple on-site methods. The cost of laboratory analysis continues to climb and the outlay for the assessment of a single site can frequently reach hundreds of thousands of dollars. One estimate suggests that the use of low cost field methods (defined as less than $100/test) with 5-20% standard laboratory confirmation could reduce analytical costs by greater than 70%. Perhaps as important as the cost of analysis is ability to obtain data about the remediation process in near real-time. The instruments normally used for environmental analysis of uranium (atomic absorption spectrophotometer, inductive coupled plasma emission spectrometer, IC-MS and kinetic phosphorescence analyzer) or can be quite expensive; these instruments are thus usually located only in centralized facilities. Environmental samples must therefore be transported to these facilities and often wait in a queue before they can be analyzed. Both sample transport and time-in-queue lead to long turn-around times (days to weeks). Such long turn-around times are especially worrisome during site remediation, especially when an unexpected finding might dictate a change in the methodologies being employed at the site. The goal of this project was to develop sensors that could yield reliable data in near realtime (< 1 hour) be field-ready (ie, simple, durable and accurate) and present low costs (<< $100/assay and <$5,000 for the initial equipment

  3. Impedimetric biosensors and immunosensors

    International Nuclear Information System (INIS)

    Prodromidis, M.I.

    2007-01-01

    The development of methods targeting the direct monitoring of antibody-antigen interactions is particularly attractive. The design of label-free affinity-based probing concepts is the objective of much current research, at both academic and industrial levels, towards establishing alternative methods to the already existing ELISA-based immunoassays. Among these, Electrochemical Impedance Spectroscopy (EIS) represents one of the most powerful methods, due to the ability of EIS-based sensors to be more easily integrated into multi-array or microprocessor, controlled diagnostic tools. During the last decade, EIS and the concept of biochemical capacitors have been widely used for probing various types of biomolecular interactions (immunosensors, DNA hybridization, protein-protein interactions). So far, impedimetric or capacitive immunosensors have been successfully applied at the academic level. However, no prototypes have been released into the market, since major fundamental issues still exist. Even though this fact has brought the reliability of impedimetric immunosensors into question, features associated with electrochemical approaches, namely the ability to be miniaturized, remote control of implanted sensors, low cost of electrode mass production and cost effective instrumentation (without need of high-energy sources) keep impedimetric sensors particularly attractive as compared to other approaches based on microbalances, surface plasmon resonance or ellipsometry. This lecture outlines the theoretical background of impedimetric immunosensors and presents different types of impedimetric biosensors as well as the instrumental approaches that have been so far proposed in the literature. (author)

  4. Analytical techniques for in-line/on-line monitoring of uranium and plutonium in process solutions : a brief literature survey

    International Nuclear Information System (INIS)

    Marathe, S.G.; Sood, D.D.

    1991-01-01

    In-line/on-line monitoring of various parameters such as uranium-plutonium-fission product concentration, acidity, density etc. plays an important role in quickly understanding the efficiency of processes in a reprocessing plant. Efforts in studying and installation of such analytical instruments are going on since more than three decades with adaptation of newer methods and technologies. A review on the developement of in-line analytical instrumentation was carried out in this laboratory about two decades ago. This report presents a very short literature survey of the work in the last two decades. The report includes an outline of principles of the main techniques employed in the in-line/on-line monitoring. (author). 77 refs., 6 tabs

  5. Automated instruments for in-line accounting of highly enriched uranium at the Oak Ridge Y-12 Plant

    International Nuclear Information System (INIS)

    Russo, P.A.; Strittmatter, R.B.; Sandford, E.L.; Stephens, M.M.; Brumfield, T.L.; Smith, S.E.; McCullough, E.E.; Jeter, I.W.; Bowers, G.L.

    1985-02-01

    Two automated nondestructive assay instruments developed at Los Alamos in support of nuclear materials accounting needs are currently operating in-line at the Oak Ridge Y-12 facility for recovery of highly enriched uranium (HEU). One instrument provides the HEU inventory in the secondary solvent extraction system, and the other monitors HEU concentration in the secondary intermediate evaporator. Both instruments were installed in December 1982. Operational evaluation of these instruments was a joint effort of Y-12 and Los Alamos personnel. This evaluation included comparison of the solvent extraction system inventories with direct measurements performed on the dumped solution components of the solvent extraction system and comparison of concentration assay results with the external assays of samples withdrawn from the process. The function and design of the instruments and detailed results of the operational evaluation are reported

  6. Uranium

    International Nuclear Information System (INIS)

    Hamdoun, N.A.

    2007-01-01

    The article includes a historical preface about uranium, discovery of portability of sequential fission of uranium, uranium existence, basic raw materials, secondary raw materials, uranium's physical and chemical properties, uranium extraction, nuclear fuel cycle, logistics and estimation of the amount of uranium reserves, producing countries of concentrated uranium oxides and percentage of the world's total production, civilian and military uses of uranium. The use of depleted uranium in the Gulf War, the Balkans and Iraq has caused political and environmental effects which are complex, raising problems and questions about the effects that nuclear compounds left on human health and environment.

  7. Uranium

    International Nuclear Information System (INIS)

    Cuney, M.; Pagel, M.; Leroy, J.

    1992-01-01

    First, this book presents the physico-chemical properties of Uranium and the consequences which can be deduced from the study of numerous geological process. The authors describe natural distribution of Uranium at different scales and on different supports, and main Uranium minerals. A great place in the book is assigned to description and classification of uranium deposits. The book gives also notions on prospection and exploitation of uranium deposits. Historical aspects of Uranium economical development (Uranium resources, production, supply and demand, operating costs) are given in the last chapter. 7 refs., 17 figs

  8. Uranium

    International Nuclear Information System (INIS)

    Anon.

    1984-01-01

    The article briefly discusses the Australian government policy and the attitude of political party factions towards the mining and exporting of the uranium resources in Australia. Australia has a third of the Western World's low-cost uranium resources

  9. Uranium

    International Nuclear Information System (INIS)

    Poty, B.; Cuney, M.; Bruneton, P.; Virlogeux, D.; Capus, G.

    2010-01-01

    With the worldwide revival of nuclear energy comes the question of uranium reserves. For more than 20 years, nuclear energy has been neglected and uranium prospecting has been practically abandoned. Therefore, present day production covers only 70% of needs and stocks are decreasing. Production is to double by 2030 which represents a huge industrial challenge. The FBR-type reactors technology, which allows to consume the whole uranium content of the fuel, is developing in several countries and will ensure the long-term development of nuclear fission. However, the implementation of these reactors (the generation 4) will be progressive during the second half of the 21. century. For this reason an active search for uranium ores will be necessary during the whole 21. century to ensure the fueling of light water reactors which are huge uranium consumers. This dossier covers all the aspects of natural uranium production: mineralogy, geochemistry, types of deposits, world distribution of deposits with a particular attention given to French deposits, the exploitation of which is abandoned today. Finally, exploitation, ore processing and the economical aspects are presented. Contents: 1 - the uranium element and its minerals: from uranium discovery to its industrial utilization, the main uranium minerals (minerals with tetravalent uranium, minerals with hexavalent uranium); 2 - uranium in the Earth's crust and its geochemical properties: distribution (in sedimentary rocks, in magmatic rocks, in metamorphic rocks, in soils and vegetation), geochemistry (uranium solubility and valence in magmas, uranium speciation in aqueous solution, solubility of the main uranium minerals in aqueous solution, uranium mobilization and precipitation); 3 - geology of the main types of uranium deposits: economical criteria for a deposit, structural diversity of deposits, classification, world distribution of deposits, distribution of deposits with time, superficial deposits, uranium

  10. Uranium

    International Nuclear Information System (INIS)

    Mackay, G.A.

    1978-01-01

    The author discusses the contribution made by various energy sources in the production of electricity. Estimates are made of the future nuclear contribution, the future demand for uranium and future sales of Australian uranium. Nuclear power growth in the United States, Japan and Western Europe is discussed. The present status of the six major Australian uranium deposits (Ranger, Jabiluka, Nabarlek, Koongarra, Yeelerrie and Beverley) is given. Australian legislation relevant to the uranium mining industry is also outlined

  11. Uranium

    International Nuclear Information System (INIS)

    1982-01-01

    The development, prospecting, research, processing and marketing of South Africa's uranium industry and the national policies surrounding this industry form the headlines of this work. The geology of South Africa's uranium occurences and their positions, the processes used in the extraction of South Africa's uranium and the utilisation of uranium for power production as represented by the Koeberg nuclear power station near Cape Town are included in this publication

  12. Uranium

    International Nuclear Information System (INIS)

    Stewart, E.D.J.

    1974-01-01

    A discussion is given of uranium as an energy source in The Australian economy. Figures and predictions are presented on the world supply-demand position and also figures are given on the added value that can be achieved by the processing of uranium. Conclusions are drawn about Australia's future policy with regard to uranium (R.L.)

  13. Uranium

    International Nuclear Information System (INIS)

    Toens, P.D.

    1981-03-01

    The geological setting of uranium resources in the world can be divided in two basic categories of resources and are defined as reasonably assured resources, estimated additional resources and speculative resources. Tables are given to illustrate these definitions. The increasing world production of uranium despite the cutback in the nuclear industry and the uranium requirements of the future concluded these lecture notes

  14. Field-Portable Immunoassay Instruments and Reagents to Measure Chelators and Mobile Forms of Uranium

    International Nuclear Information System (INIS)

    Blake, Diane A.

    2006-01-01

    Progress Report Date: 01/23/06 (report delayed due to Hurricane Katrina) Report of results to date: The goals of this 3-year project are to: (1) update and successfully deploy our present immunosensors at DOE sites; (2) devise immunosensor-based assays for Pb(II), Hg(II), chelators, and/or Cr(III) in surface and groundwater; and (3) develop new technologies in antibody engineering that will enhance this immunosensor program. Note: Work on this project was temporarily disrupted when Hurricane Katrina shut down the University on August 29, 2005. While most of the reagents stored in our refrigerators and freezers were destroyed, all of our hybridoma cell lines were saved because they had been stored in liquid nitrogen. We set up new tissue culture reactors with the hybridomas that synthesize the anti-uranium antibodies, and are purifying new monoclonal antibodies from these culture supernatants. Both the in-line and the field-portable sensor were rescued from our labs in New Orleans in early October, and we continued experiments with these sensors in the temporary laboratory we set up in Hammond, LA at Southeastern Louisiana University

  15. Uranium

    International Nuclear Information System (INIS)

    Whillans, R.T.

    1981-01-01

    Events in the Canadian uranium industry during 1980 are reviewed. Mine and mill expansions and exploration activity are described, as well as changes in governmental policy. Although demand for uranium is weak at the moment, the industry feels optimistic about the future. (LL)

  16. Uranium

    Energy Technology Data Exchange (ETDEWEB)

    Williams, R M

    1976-01-01

    Evidence of expanding markets, improved prices and the short supply of uranium became abundantly clear in 1975, providing the much needed impetus for widespread activity in all phases of uranium operations. Exploration activity that had been at low levels in recent years in Canada was evident in most provinces as well as the Northwest Territories. All producers were in the process of expanding their uranium-producing facilities. Canada's Atomic Energy Control Board (AECB) by year-end had authorized the export of over 73,000 tons of U/sub 3/0/sub 8/ all since September 1974, when the federal government announced its new uranium export guidelines. World production, which had been in the order of 25,000 tons of U/sub 3/0/sub 8/ annually, was expected to reach about 28,000 tons in 1975, principally from increased output in the United States.

  17. Uranium

    International Nuclear Information System (INIS)

    Perkin, D.J.

    1982-01-01

    Developments in the Australian uranium industry during 1980 are reviewed. Mine production increased markedly to 1841 t U 3 O 8 because of output from the new concentrator at Nabarlek and 1131 t of U 3 O 8 were exported at a nominal value of $37.19/lb. Several new contracts were signed for the sale of yellowcake from Ranger and Nabarlek Mines. Other developments include the decision by the joint venturers in the Olympic Dam Project to sink an exploration shaft and the release of an environmental impact statement for the Honeymoon deposit. Uranium exploration expenditure increased in 1980 and additions were made to Australia's demonstrated economic uranium resources. A world review is included

  18. Uranium

    International Nuclear Information System (INIS)

    Gabelman, J.W.; Chenoweth, W.L.; Ingerson, E.

    1981-01-01

    The uranium production industry is well into its third recession during the nuclear era (since 1945). Exploration is drastically curtailed, and many staffs are being reduced. Historical market price production trends are discussed. A total of 3.07 million acres of land was acquired for exploration; drastic decrease. Surface drilling footage was reduced sharply; an estimated 250 drill rigs were used by the uranium industry during 1980. Land acquisition costs increased 8%. The domestic reserve changes are detailed by cause: exploration, re-evaluation, or production. Two significant discoveries of deposits were made in Mohave County, Arizona. Uranium production during 1980 was 21,850 short tons U 3 O 8 ; an increase of 17% from 1979. Domestic and foreign exploration highlights were given. Major producing areas for the US are San Juan basin, Wyoming basins, Texas coastal plain, Paradox basin, northeastern Washington, Henry Mountains, Utah, central Colorado, and the McDermitt caldera in Nevada and Oregon. 3 figures, 8 tables

  19. Uranium

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    Recent decisions by the Australian Government will ensure a significant expansion of the uranium industry. Development at Roxby Downs may proceed and Ranger may fulfil two new contracts but the decision specifies that apart from Roxby Downs, no new mines should be approved. The ACTU maintains an anti-uranium policy but reaction to the decision from the trade union movement has been muted. The Australian Science and Technology Council (ASTEC) has been asked by the Government to conduct an inquiry into a number of issues relating to Australia's role in the nuclear fuel cycle. The inquiry will examine in particular Australia's nuclear safeguards arrangements and the adequacy of existing waste management technology. In two additional decisions the Government has dissociated itself from a study into the feasibility of establishing an enrichment operation and has abolished the Uranium Advisory Council. Although Australian reserves account for 20% of the total in the Western World, Australia accounts for a relatively minor proportion of the world's uranium production

  20. Uranium

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    The French Government has decided to freeze a substantial part of its nuclear power programme. Work has been halted on 18 reactors. This power programme is discussed, as well as the effect it has on the supply of uranium by South Africa

  1. Recent Advances in Electrochemical Immunosensors

    Directory of Open Access Journals (Sweden)

    Benoît Piro

    2017-04-01

    Full Text Available Immunosensors have experienced a very significant growth in recent years, driven by the need for fast, sensitive, portable and easy-to-use devices to detect biomarkers for clinical diagnosis or to monitor organic pollutants in natural or industrial environments. Advances in the field of signal amplification using enzymatic reactions, nanomaterials such as carbon nanotubes, graphene and graphene derivatives, metallic nanoparticles (gold, silver, various oxides or metal complexes, or magnetic beads show how it is possible to improve collection, binding or transduction performances and reach the requirements for realistic clinical diagnostic or environmental control. This review presents these most recent advances; it focuses first on classical electrode substrates, then moves to carbon-based nanostructured ones including carbon nanotubes, graphene and other carbon materials, metal or metal-oxide nanoparticles, magnetic nanoparticles, dendrimers and, to finish, explore the use of ionic liquids. Analytical performances are systematically covered and compared, depending on the detection principle, but also from a chronological perspective, from 2012 to 2016 and early 2017.

  2. Uranium

    International Nuclear Information System (INIS)

    Battey, G.C.; McKay, A.D.

    1988-01-01

    Production for 1986 was 4899 t U 3 O 8 (4154 t U), 30% greater than in 1985, mainly because of a 39% increase in production at Ranger. Exports for 1986 were 4166 t U 3 O 8 at an average f.o.b. unit value of $40.57/lb U 3 O 8 . Private exploration expenditure for uranium in Australia during the 1985-86 fiscal year was $50.2 million. Plans were announced to increase the nominal capacity of the processing plant at Ranger from 3000 t/year U 3 O 8 to 4500 t and later to 6000 t/year. Construction and initial mine development at Olympic Dam began in March. Production is planned for mid 1988 at an annual rate of 2000 t U 3 O 8 , 30 000 t Cu, and 90 000 oz (2800 kg) Au. The first long-term sales agreement was concluded in September 1986. At the Manyingee deposit, testing of the alkaline solution mining method was completed, and the treatment plant was dismantled. Spot market prices (in US$/lb U 3 O 8 ) quoted by Nuexco were generally stable. From January-October the exchange value fluctuated from US$17.00-US$17.25; for November and December it was US$16.75. Australia's Reasonably Assured Resources of uranium recoverable at less than US$80/kg U at December 1986 were estimated as 462 000 t U, 3000 t U less than in 1985. This represents 30% of the total low-cost RAR in the WOCA (World Outside the Centrally Planned Economy Areas) countries. Australia also has 257 000 t U in the low-cost Estimated Additional Resources Category I, 29% of the WOCA countries' total resources in this category

  3. Optical fiber immunosensor based on polarimetry

    NARCIS (Netherlands)

    Kooyman, R.P.H.; Heideman, Rene; Koster, R.; Greve, Jan

    1991-01-01

    The authors discuss a type of evanescent field fiber immunosensor, based upon a polarimetric detection scheme. In this method the refractive indices of the involved chemical compounds are used as reporters of the binding event; no external label molecules are required. It is demonstrated that a

  4. Development of a contactless capacitive immunosensor

    OpenAIRE

    Perruche, Brice Emmanuel

    2011-01-01

    In the present work, a label-free, contactless and capacitive immunosensor is developed using impedance spectroscopy, in the aim to perform low-cost immunoassays. Chapter 1 puts this work in perspective with some existing techniques, while a presentation of impedance theory used in this work is carried out in chapter 2. In Chapter 3, numerical simulations using a commercial finite element method software is carried out. The response of coplanar and fa...

  5. Ultrasensitive interdigitated capacitance immunosensor using gold nanoparticles

    Science.gov (United States)

    Alizadeh Zeinabad, Hojjat; Ghourchian, Hedayatollah; Falahati, Mojtaba; Fathipour, Morteza; Azizi, Marzieh; Boutorabi, Seyed Mehdi

    2018-06-01

    Immunosensors based on interdigitated electrodes (IDEs), have recently demonstrated significant improvements in the sensitivity of capacitance detection. Herein, a novel type of highly sensitive, compact and portable immunosensor based on a gold interdigital capacitor has been designed and developed for the rapid detection of hepatitis B surface antigen (HBsAg). To improve the efficiency of antibody immobilization and time-saving, a self-assembled monolayer (SAM) of 2-mercaptoethylamine film was coated on IDEs. Afterwards, carboxyl groups on primary antibodies were activated through 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and were immobilized on amino-terminated SAM for better control of the oriented immobilization of antibodies on gold IDEs. In addition, gold nanoparticles conjugated with a secondary antibody were used to enhance the sensitivity. Under optimal conditions, the immunosensor exhibited the sensitivity of 0.22 nF.pg ml–1, the linear range from 5 pg ml‑1 to 1 ng ml–1 and the detection limit of 1.34 pg ml‑1, at a signal-to-noise ratio of 3.

  6. Electrochemical immunosensors - A powerful tool for analytical applications.

    Science.gov (United States)

    Felix, Fabiana S; Angnes, Lúcio

    2018-04-15

    Immunosensors are biosensors based on interactions between an antibody and antigen on a transducer surface. Either antibody or antigen can be the species immobilized on the transducer to detect antigen or antibody, respectively. Because of the strong binding forces between these biomolecules, immunosensors present high selectivity and very high sensitivity, making them very attractive for many applications in different science fields. Electrochemical immunosensors explore measurements of an electrical signal produced on an electrochemical transductor. This signal can be voltammetric, potentiometric, conductometric or impedimetric. Immunosensors utilizing electrochemical detection have been explored in several analyses since they are specific, simple, portable, and generally disposable and can carry out in situ or automated detection. This review addresses the potential of immunosensors destined for application in food and environmental analysis, and cancer biomarker diagnosis. Emphasis is given to the approaches that have been used for construction of electrochemical immunosensors. Additionally, the fundamentals of immunosensors, technology of transducers and nanomaterials and a general overview of the possible applications of electrochemical immunosensors to the food, environmental and diseases analysis fields are described. Copyright © 2017. Published by Elsevier B.V.

  7. Recent advances in immunosensor for narcotic drug detection

    Science.gov (United States)

    Gandhi, Sonu; Suman, Pankaj; Kumar, Ashok; Sharma, Prince; Capalash, Neena; Suri, C. Raman

    2015-01-01

    Introduction: Immunosensor for illicit drugs have gained immense interest and have found several applications for drug abuse monitoring. This technology has offered a low cost detection of narcotics; thereby, providing a confirmatory platform to compliment the existing analytical methods. Methods: In this minireview, we define the basic concept of transducer for immunosensor development that utilizes antibodies and low molecular mass hapten (opiate) molecules. Results: This article emphasizes on recent advances in immunoanalytical techniques for monitoring of opiate drugs. Our results demonstrate that high quality antibodies can be used for immunosensor development against target analyte with greater sensitivity, specificity and precision than other available analytical methods. Conclusion: In this review we highlight the fundamentals of different transducer technologies and its applications for immunosensor development currently being developed in our laboratory using rapid screening via immunochromatographic kit, label free optical detection via enzyme, fluorescence, gold nanoparticles and carbon nanotubes based immunosensing for sensitive and specific monitoring of opiates. PMID:26929925

  8. EIS immunosensor based on magnetic nanoparticles for ochratoxim A determination

    International Nuclear Information System (INIS)

    Biraruti, Irina; Tudorache, Madalina; Rotariu, Lucian; Bala, Camelia; Jaffrezic-Renault, Nicole

    2009-01-01

    Full text: Ochratoxin A (OTA) is a mycotoxin produced by Aspergillus and Penicillium fungi. It occurs in a variety of foodstuff, including cereals, coffee, wine, grape juice and fruits juice. Maximum permitted levels have been established by the EU and several countries. Currently, there are several methods available for OTA monitoring in real samples, e.g. TLC, HPLC, ELISA immunosensors. Liquid chromatography with fluorescence detection (HPLC-FLD), coupled with immunoaffinity column or solid phase extraction as pretreatment method, has been validated and adopted as official standard for OTA determination. Also, an immunosensor based on electrochemical detection has been reported for rapid analysis of OTA in food and beverages. Our work proposes the development of a new sensitive immunosensor combining the use of magnetic nanoparticles and EIS (electrochemical impedance spectroscopy) detection principle. Anti-OTA antibody immobilised on magnetic nanoparticles were deposited on the EIS electrode surface by applying a magnetic field. Then, OTA sample solutions were added in the detection cell. Quantitative determination of OTA content was performed based on EIS detection. Experimental parameters of the immunosensor were set-up at the optimum values. Based on those values, the immunosensor allows to detect OTA in the range 1-10 ng/mL. The future perspective is to validate this immunochemical method using HPLC-FLD. (authors)

  9. Introduction to Biosensors From Electric Circuits to Immunosensors

    CERN Document Server

    Yoon, Jeong-Yeol

    2013-01-01

    Introduction to Biosensors: From Electric Circuits to Immunosensors discusses underlying circuitry of sensors for biomedical and biological engineers as well as biomedical sensing modalities for electrical engineers while providing an applications-based approach to the study of biosensors with over 13 extensive, hands-on labs. The material is presented using a building-block approach, beginning with the fundamentals of sensor design and temperature sensors and ending with more complicated biosensors. This book also: Provides electrical engineers with the specific knowledge they need to understand biological sensing modalities Provides biomedical engineers with a solid background in circuits and systems Includes complete coverage of temperature sensors, electrochemical sensors, DNA and immunosensors, piezoelectric sensors and immunosensing in a micofluidic device Introduction to Biosensors: From Electric Circuits to Immunosensors aims to provide an interdisciplinary approach to biosensors that will be apprecia...

  10. Disposable amperometric immunosensor based on layer-by-layer ...

    Indian Academy of Sciences (India)

    Administrator

    immunosensor displays a broad linear response to AFP, the working range being 0⋅25 to 300⋅0 ng mL. –1 ... pregnant women who have high levels of AFP may indicate infants with ... and factors influencing the performance of the resulting ...

  11. Advancements and application of immunosensors in the analysis of food contaminants

    Directory of Open Access Journals (Sweden)

    MD. SHOFIUL AZAM

    2014-11-01

    Full Text Available Azam MS, Rahman MRT, Lou Z, Tang Y, Raqib SM, Jothi JS. 2014. Advancements and application of immunosensors in the analysis of food contaminants. Nusantara Bioscience 6: 186-195. Immunosensors are affinity ligand-based biosensor solid-state devices in which the immunochemical reaction is coupled to a transducer. The fundamental basis of all immunosensors is the specificity of the molecular recognition of antigens by antibodies to form a stable complex. This is similar to the immunoassay methodology. Immunosensors can be categorized based on the detection principle applied. The main developments are electrochemical, optical, and microgravimetric immunosensors. In contrast to immunoassay, modern transducer technology enables the label-free detection and quantification of the immune complex. The analysis of trace substances in environmental science, pharmaceutical and food industries is a challenge since many of these applications demand a continuous monitoring mode. The use of immunosensors in these applications is most appropriate. Food chemists should take advantage of immunosensors in food and clinical diagnostics. There are many recent developments in the immunosensor field which have potential impacts. The future role of this technique in intra-laboratory, as well as bedside testing, will become even more important as the food laboratory is faced with increasing pressure to contain costs. Objective of this paper is to give a general overview of the possible application of immunosensors to the food analysis field.

  12. An electrochemical immunosensor for quantitative detection of ficolin-3

    Science.gov (United States)

    San, Lili; Zeng, Dongdong; Song, Shiping; Zuo, Xiaolei; Zhang, Huan; Wang, Chenguang; Wu, Jiarui; Mi, Xianqiang

    2016-06-01

    Diabetes mellitus (DM) is one of the most common metabolic disorders in the world, of which more than 90% is type-2 diabetes mellitus (T2DM). There is a rather urgent need for reliable, sensitive and quick detection techniques in clinical application of T2DM. Ficolin-3 is a potential biomarker of T2DM, because serum ficolin-3 levels are associated with insulin resistance and predict the incidence of T2DM. Herein, a sandwich-type electrochemical immunosensor was developed for the detection of ficolin-3 in human serum. Cyclic voltammetry and the amperometric current versus time were used to characterize the performance of the immunosensor. Under optimal conditions, the detection limitation of ficolin-3 was 100 ng ml-1 and the linear dynamic range was between 2 and 50 μg ml-1. The method has ideal accuracy, excellent stability and selectivity and has wide application prospects in clinical research.

  13. Bismuth oxide nanorods based immunosensor for mycotoxin detection

    Energy Technology Data Exchange (ETDEWEB)

    Solanki, Pratima R., E-mail: pratimarsolanki@gmail.com [DST Centre for Biomolecular Electronics, CSIR-National Physical Laboratory, K.S. Krishnan Marg, New Delhi (India); Special Centre for Nano Sciences, Jawaharlal Nehru University, New Delhi 110067 (India); Singh, Jay [DST Centre for Biomolecular Electronics, CSIR-National Physical Laboratory, K.S. Krishnan Marg, New Delhi (India); Department of Applied Chemistry and Polymer Technology, Delhi Technological University, Shahbad Daulatpur, Main Bawana Road, Delhi 110042 (India); Rupavali, Bharti [DST Centre for Biomolecular Electronics, CSIR-National Physical Laboratory, K.S. Krishnan Marg, New Delhi (India); Tiwari, Sachchidanand [Special Centre for Nano Sciences, Jawaharlal Nehru University, New Delhi 110067 (India); Malhotra, Bansi D., E-mail: bansi.malhotra@gmail.com [DST Centre for Biomolecular Electronics, CSIR-National Physical Laboratory, K.S. Krishnan Marg, New Delhi (India); Department of Biotechnology, Delhi Technological University, Shahbad Daulatpur, Main Bawana Road, Delhi 110042 (India)

    2017-01-01

    We report results of the studies relating to fabrication of an efficient immunosensor based on bismuth oxide nanorods (nBi{sub 2}O{sub 3}), electrophoretically deposited onto indium-tin-oxide (ITO) coated glass substrate. This immunosensor was fabricated by immobilization of anti-aflatoxin monoclonal antibodies (Ab-AFB1) and bovine serum albumin (BSA) for aflatoxin B1 detection. The structural and morphological studies of n-Bi{sub 2}O{sub 3} have been carried out by XRD, UV–vis spectrophotometer; SEM, AFM and FTIR. It was found that the nBi{sub 2}O{sub 3} provided improved sensing characteristics to the electrode interface in terms of electroactive surface area, diffusion coefficient, charge transfer rate constant and electron transfer kinetics. The results of electrochemical response studies of this BSA/Ab-AFB1/nBi{sub 2}O{sub 3}/ITO immunosensor revealed good linearity in the range of 1–70 ng dL{sup −1} with low detection limit of 8.715 ng/dL, improved sensitivity of 1.132 μA/(ng/dL cm{sup −2}), regression coefficient R{sup 2} of 0.918 and reproducibility of > 11 times. The association constant for the BSA/Ab-AFB1/nBi{sub 2}O{sub 3}/ITO immunosensor was determined as 7.318 ng/dL. - Highlights: • Use of Bismuth oxide nanorods for aflatoxin B1 detection. • It improved the electrochemical properties. • First report on nBi{sub 2}O{sub 3} for mycotoxin detection.

  14. Nanomaterial-Based Electrochemical Immunosensors for Clinically Significant Biomarkers

    Directory of Open Access Journals (Sweden)

    Niina J. Ronkainen

    2014-06-01

    Full Text Available Nanotechnology has played a crucial role in the development of biosensors over the past decade. The development, testing, optimization, and validation of new biosensors has become a highly interdisciplinary effort involving experts in chemistry, biology, physics, engineering, and medicine. The sensitivity, the specificity and the reproducibility of biosensors have improved tremendously as a result of incorporating nanomaterials in their design. In general, nanomaterials-based electrochemical immunosensors amplify the sensitivity by facilitating greater loading of the larger sensing surface with biorecognition molecules as well as improving the electrochemical properties of the transducer. The most common types of nanomaterials and their properties will be described. In addition, the utilization of nanomaterials in immunosensors for biomarker detection will be discussed since these biosensors have enormous potential for a myriad of clinical uses. Electrochemical immunosensors provide a specific and simple analytical alternative as evidenced by their brief analysis times, inexpensive instrumentation, lower assay cost as well as good portability and amenability to miniaturization. The role nanomaterials play in biosensors, their ability to improve detection capabilities in low concentration analytes yielding clinically useful data and their impact on other biosensor performance properties will be discussed. Finally, the most common types of electroanalytical detection methods will be briefly touched upon.

  15. Development of optical immunosensors for detection of proteins in serum.

    Science.gov (United States)

    Kyprianou, Dimitris; Chianella, Iva; Guerreiro, Antonio; Piletska, Elena V; Piletsky, Sergey A

    2013-01-15

    The detection of proteins in biological samples such as blood, serum or plasma by biosensors is very challenging due to the complex nature of the matrix, which contains a high level of many interfering compounds. Here we show the application of a novel polymeric immobilisation matrix that helps in the detection of specific protein analytes in biological samples by surface plasmon resonance (SPR) immunosensors. This polymer matrix contains thioacetal functional groups included in the network, and these groups do not require any further activation in order to react with proteins, making it attractive for sensor fabrication. The protein prostate specific antigen (PSA) was selected as a model target analyte. A sandwich format with two primary antibodies recognising different parts (epitopes) of the analyte was used for the detection of PSA in serum. The efficiency of the reduction of non-specific binding achieved with novel polymer was compared with those of other techniques such as coating of sensor surface with polyethylene glycol (PEG), use of charged hydrophilic aspartic acid and surfactants such as Tween20. The detection limit of the polymer based immunosensor was 0.1 ng ml(-1) for free form PSA (f-PSA) in buffer and 5 ng ml(-1) in 20% serum. This is an improvement compared with similar devices reported on literature, indicating the potential of the immunosensor developed here for the analysis of real samples. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Impedimetric immunosensor for detection of cardiovascular disorder risk biomarker

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Raju, E-mail: khan.raju@gmail.com [Analytical Chemistry Division, CSIR-North East Institute of Science & Technology, Academy of Scientific and Innovative Research, Jorhat 785006, Assam (India); Pal, Mintu [Biotechnology Division, CSIR-North East Institute of Science & Technology, Academy of Scientific and Innovative Research, Jorhat 785006, Assam (India); Kuzikov, Alexey V.; Bulko, Tanya; Suprun, Elena V.; Shumyantseva, Victoria V. [Institute of Biomedical Chemistry, Pogodinskaya Street, 10, Moscow 119121 (Russian Federation)

    2016-11-01

    We report the construction and characterization of a novel, level free impedimetric immunosensor for rapid, sensitive and selective detection of myoglobin (Mb). Monoclonal anti-myoglobin (anti-Mb-IgG) antibody was immobilized on screen-printed multiwalled carbon nanotubes electrode for signal amplification without the need of natural enzymes. The fabrication of resulting immunosensor was extensively characterized by using scanning electron microscopy (SEM), fourier transform infrared (FT-IR) spectroscopy, cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). Electrochemical impedance spectroscopy (EIS) technique offered a linear detection range (0.1–90 ng mL{sup −1}) of myoglobin with sensitivity of 0.74 kΩ ng mL{sup −1} (correlation coefficient, R{sup 2} = 0.97) and detection limit of 0.08 ng mL{sup −1} (S/N = 3). The mean percentage recovery of Mb in serum samples using this working biosensor is 97.33%. Furthermore, the proposed strategy can be a promising alternative for detection of Mb related cardiovascular disorders. - Highlights: • Fabrication of impedimetric immunosensor based on SPEs-MWCNTs for the detection of myoglobin. • Immobilization of monoclonal myoglobin antibody on the electrode surface was confirmed by EIS and SEM. • The sensitivity of myoglobin is 0.74 kΩ ngmL{sup -1} with detection limit of 0.08 ngmL{sup -1}.

  17. Interferometer immunosensor based on porous silicon for determining alpha-fetoprotein

    Science.gov (United States)

    Lv, Xiaoyi; Jiang, Jing; Lv, Guodong; Mo, Jiaqing; Jia, Zhenhong

    2016-10-01

    An increased level of alpha-fetoprotein ( AFP) in the blood may be a sign of liver cancer. Porous silicon based optical microcavities structure is prepared as a label-free immunosensor platform for detecting AFP. After the antigen-antibody reaction, it is monitored that the red shift of the reflection spectrum of the immunosensor increases

  18. Smartphone-based immunosensor for CA125 detection.

    Science.gov (United States)

    Hosu, Oana; Ravalli, Andrea; Lo Piccolo, Giuseppe Mattia; Cristea, Cecilia; Sandulescu, Robert; Marrazza, Giovanna

    2017-05-01

    In this work, we report the design, the development and the characterization of the analytical performances of a colorimetric smartphone-based immunosensor for the detection of cancer antigen 125 (CA125). The immunosensor was based on a sandwich strategy in which the primary antibody was immobilized by spotting onto the 3D nitrocellulose membrane. The immunospots were subsequently incubated with CA125 solutions, followed by the affinity reaction with a secondary antibody labeled with gold nanoparticles (AuNPs). The antibody-AuNPs captured onto immunospots induced the silver deposition from a silver enhancer solution leading to the formation of gold-silver nanoparticles of different grey color spots depending on CA125 concentration. The 8 megapixels smartphone camera was integrated in a home-made dark box and used as transducer of color image acquisition and data handling. The pixel intensity of the captured images was determined by an image processing algorithm. The experimental parameters involved in each step of the immunosensor design were studied and optimized, obtaining a limit of detection of 30U/mL CA125. The selectivity of the immunoassay was proven against different concentration solutions of Vascular Endothelial Growth Factor (VEGF) antigen as an unspecific protein when a blank signal was obtained for all tested solutions. Finally, preliminary experiments in human serum samples spiked with CA125 protein were also performed. Therefore, the proposed system could represent a powerful point-of-care tool for the next generation technology for detecting and monitoring cancer biomarkers at early stages by taking advantage of nowadays gadgets with enhanced features such as smartphones. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. An electrochemical immunosensor based on pristine graphene for rapid determination of ractopamine

    Science.gov (United States)

    Qi, Shaopeng; Zhao, Bo; Zhou, Bo; Jiang, Xiaoqing

    2017-10-01

    A new electrochemical immunosensor for fast determination of ractopamine (RAC) is fabricated based on pristine graphene (PG). The PG provides a microenvironment beneficial the immobilization of RAC, promotes the electron transfer, and raises the sensitivity of the immunosensor. The free RAC in solution can be effectively measured based on the competitive immunoreaction between RAC-antibody and RAC. The calibration graph shows linearity over the concentration ranges of 0.1-10 and 10-4000 ng mL-1. The proposed immunosensor displays a satisfactory stability, selectivity, and reproducibility and has been applied to the quantificational detection of RAC in real pork samples.

  20. Current Technologies of Electrochemical Immunosensors: Perspective on Signal Amplification

    Directory of Open Access Journals (Sweden)

    Il-Hoon Cho

    2018-01-01

    Full Text Available An electrochemical immunosensor employs antibodies as capture and detection means to produce electrical charges for the quantitative analysis of target molecules. This sensor type can be utilized as a miniaturized device for the detection of point-of-care testing (POCT. Achieving high-performance analysis regarding sensitivity has been one of the key issues with developing this type of biosensor system. Many modern nanotechnology efforts allowed for the development of innovative electrochemical biosensors with high sensitivity by employing various nanomaterials that facilitate the electron transfer and carrying capacity of signal tracers in combination with surface modification and bioconjugation techniques. In this review, we introduce novel nanomaterials (e.g., carbon nanotube, graphene, indium tin oxide, nanowire and metallic nanoparticles in order to construct a high-performance electrode. Also, we describe how to increase the number of signal tracers by employing nanomaterials as carriers and making the polymeric enzyme complex associated with redox cycling for signal amplification. The pros and cons of each method are considered throughout this review. We expect that these reviewed strategies for signal enhancement will be applied to the next versions of lateral-flow paper chromatography and microfluidic immunosensor, which are considered the most practical POCT biosensor platforms.

  1. Copper oxide assisted cysteine hierarchical structures for immunosensor application

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Chandra Mouli [Biomedical Instrumentation Section, CSIR-National Physical Laboratory, New Delhi 110012 (India); Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi 221005 (India); Sumana, Gajjala, E-mail: sumanagajjala@gmail.com [Biomedical Instrumentation Section, CSIR-National Physical Laboratory, New Delhi 110012 (India); Tiwari, Ida [Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi 221005 (India)

    2014-09-08

    The present work describes the promising electrochemical immunosensing strategy based on copper (II) assisted hierarchical cysteine structures (CuCys) varying from star to flower like morphology. The CuCys having average size of 10 μm have been synthesised using L-Cysteine as initial precursor in presence of copper oxide under environmentally friendly conditions in aqueous medium. To delineate the synthesis mechanism, detailed structural investigations have been carried out using characterization techniques such as X-ray diffraction, transmission electron microscopy, and Fourier transform infrared spectroscopy. The electrochemical behaviour of self-assembled CuCys on gold electrode shows surface controlled electrode reaction with an apparent electron transfer rate constant of 3.38 × 10{sup −4 }cm s{sup −1}. This innovative platform has been utilized to fabricate an immunosensor by covalently immobilizing monoclonal antibodies specific for Escherichia coli O157:H7 (E. coli). Under the optimal conditions, the fabricated immunosensor is found to be sensitive and specific for the detection of E. coli with a detection limit of 10 cfu/ml.

  2. Enzyme-less electrochemical displacement heterogeneous immunosensor for diclofenac detection.

    Science.gov (United States)

    Nguyen, T T K; Vu, T T; Anquetin, G; Tran, H V; Reisberg, S; Noël, V; Mattana, G; Nguyen, Q V; Dai Lam, Tran; Pham, M C; Piro, B

    2017-11-15

    We describe an electrochemical immunosensor based on functionalization of a working electrode by electrografting two functional diazonium salts. The first one is a molecular probe, diclofenac, coupled with an arylamine onto which a specific antibody is immobilized by affinity interactions; the second is a redox probe (a quinone) also coupled with an arylamine, able to transduce the hapten-antibody association into a change in electroactivity. The steric hindrance induced by the antibody leads to a current decrease upon binding of the antibody on the grafted molecular probe; conversely, when diclofenac is present in solution, a displacement equilibrium occurs between the target diffusing into the solution and the grafted probe. This leads to dissociation of the antibody from the electrode surface, event which is transduced into a current increase ("signal-on" detection). The detection limit is ca. 20 fM, corresponding to 6pgL -1 diclofenac, which is competitive compared to other label-free immunosensors. We demonstrate that the sensor is selective and is able to quantify diclofenac in tap water. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Label-free impedimetric immunosensor for sensitive detection of atrazine

    Energy Technology Data Exchange (ETDEWEB)

    Ionescu, Rodica E. [Universite de Lyon, Laboratoire de Sciences Analytiques, UMR CNRS 5180, Universite Claude Bernard Lyon 1, Batiment CPE, 43 Boulevard du 11 Novembre 1918, 69622 Villeurbanne Cedex (France); Gondran, Chantal; Bouffier, Laurent [Departement de Chimie Moleculaire, UMR CNRS 5250, ICMG FR CNRS 2607, Universite Joseph Fourier, BP 53, 38041 Grenoble, Cedex 9 (France); Jaffrezic-Renault, Nicole, E-mail: nicole.jaffrezic@univ-lyon1.f [Universite de Lyon, Laboratoire de Sciences Analytiques, UMR CNRS 5180, Universite Claude Bernard Lyon 1, Batiment CPE, 43 Boulevard du 11 Novembre 1918, 69622 Villeurbanne Cedex (France); Martelet, Claude [Universite de Lyon, Laboratoire de Sciences Analytiques, UMR CNRS 5180, Universite Claude Bernard Lyon 1, Batiment CPE, 43 Boulevard du 11 Novembre 1918, 69622 Villeurbanne Cedex (France); Cosnier, Serge, E-mail: serge.cosnier@ujf-grenoble.f [Departement de Chimie Moleculaire, UMR CNRS 5250, ICMG FR CNRS 2607, Universite Joseph Fourier, BP 53, 38041 Grenoble, Cedex 9 (France)

    2010-08-30

    Impedance spectroscopy transduction combined with the immunosensor technology has been used for the determination of atrazine, a herbicide The sensor electrode was based on the immobilization of anti-atrazine antibody by affinity binding onto a polypyrrole film N-substituted by nitrilotriacetic acid NTA electrogenerated on a gold electrode. The poly NTA film was previously modified by the coordination of Cu2 ions by the chelating NTA centers. The anti-atrazine antibody Fab fragment K47 modified with histidine-tag was then anchored by affinity interactions between the histidine-tag and the coordinated Cu2. Cyclic voltammetry experiments confirm that the antibody immobilization and the resulting immunosensor were applied to the impedimetric detection of atrazine without reagent and labelling step. The immunoreaction of atrazine on the attached anti-atrazine antibody directly triggers an increase in the charge transfer resistance proportional to the atrazine concentration, allowing the detection of extremely low atrazine concentration, namely 10 pg mL{sup -1}.

  4. Single-walled carbon nanotube based transparent immunosensor for detection of a prostate cancer biomarker osteopontin

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Abhinav; Hong, Seongkyeol; Singh, Renu [School of Mechanical and Nuclear Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798 (Korea, Republic of); Jang, Jaesung, E-mail: jjang@unist.ac.kr [School of Mechanical and Nuclear Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798 (Korea, Republic of); Department of Biomedical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798 (Korea, Republic of); School of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798 (Korea, Republic of)

    2015-04-15

    Highlights: • A transparent CNT immunosensor is presented for detection of a prostate cancer biomarker osteopontin. • This immunosensor showed a highly linear and reproducible behavior from 1 pg mL{sup −1} to 1 μg mL{sup −1}. • The limit of detection of the immunosensor was 0.3 pg mL{sup −1}. • This immunosensor demonstrated high selectivity against bovine serum albumin and human serum. - Abstract: Osteopontin (OPN) is involved in almost all steps of cancer development, and it is being investigated as a potential biomarker for a diagnosis and prognosis of prostate cancer. Here, we report a label-free, highly sensitive and transparent immunosensor based on single-walled carbon nanotubes (SWCNTs) for detection of OPN. A high density of −COOH functionalized SWCNTs was deposited between two gold/indium tin oxide electrodes on a glass substrate by dielectrophoresis. Monoclonal antibodies specific to OPN were covalently immobilized on the SWCNTs. Relative resistance change of the immunosensors was measured as the concentration of OPN in phosphate buffer saline (PBS) and human serum was varied from 1 pg mL{sup −1} to 1 μg mL{sup −1} for different channel lengths of 2, 5, and 10 μm, showing a highly linear and reproducible behavior (R{sup 2} > 97%). These immunosensors were also specific to OPN against another test protein, bovine serum albumin, PBS and human serum, showing that a limit of detection for OPN was 0.3 pg mL{sup −1}. This highly sensitive and transparent immunosensor has a great potential as a simple point-of-care test kit for various protein biomarkers.

  5. Label-free electrochemical immunosensor based on cerium oxide nanowires for Vibrio cholerae O1 detection

    International Nuclear Information System (INIS)

    Tam, Phuong Dinh; Thang, Cao Xuan

    2016-01-01

    This paper developed a label-free immunosensor based on cerium oxide nanowire for Vibrio cholerae O1 detection application. The CeO 2 nanowires were synthesized by hydrothermal reaction. The immobilization of Anti-V. cholerae O1 onto CeO 2 nanowire-deposited sensor was performed via an amino ester, which was created by using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide, and sulfo-N-hydroxysuccinimide. The electrochemical responses of the immunosensor were studied by electrochemical impedance spectroscopy with [Fe (CN) 6 ] 3−/4− as redox probe. A linear response in electron transfer resistance for cell of V. cholerae O1 concentration was found in the range of 1.0 × 10 2 CFU/mL to 1.0 × 10 4 CFU/mL. The detection limit of the immunosensor was 1.0 × 10 2 CFU/mL. The immunosensor sensitivity was 56.82 Ω/CFU·mL −1 . Furthermore, the parameters affecting immunosensor response were also investigated, as follows: pH value, immunoreaction time, incubation temperature, and anti-V. cholerae O1 concentration. - Highlights: • A label-free immunosensor based on cerium oxide nanowire for Vibrio cholerae O1 detection application was developed. • A linear response was found in the range of 1.0 × 10 2 CFU/mL to 1.0 × 10 4 CFU/mL. • The detection limit of the immunosensor was 1.0 × 10 2 CFU/mL. • The immunosensor sensitivity was 56.82 Ω/CFU.mL −1 .

  6. Label-free electrochemical immunosensor based on cerium oxide nanowires for Vibrio cholerae O1 detection

    Energy Technology Data Exchange (ETDEWEB)

    Tam, Phuong Dinh, E-mail: phuongdinhtam@gmail.com; Thang, Cao Xuan, E-mail: thang.caoxuan@hust.edu.vn

    2016-01-01

    This paper developed a label-free immunosensor based on cerium oxide nanowire for Vibrio cholerae O1 detection application. The CeO{sub 2} nanowires were synthesized by hydrothermal reaction. The immobilization of Anti-V. cholerae O1 onto CeO{sub 2} nanowire-deposited sensor was performed via an amino ester, which was created by using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide, and sulfo-N-hydroxysuccinimide. The electrochemical responses of the immunosensor were studied by electrochemical impedance spectroscopy with [Fe (CN) {sub 6}] {sup 3−/4−} as redox probe. A linear response in electron transfer resistance for cell of V. cholerae O1 concentration was found in the range of 1.0 × 10{sup 2} CFU/mL to 1.0 × 10{sup 4} CFU/mL. The detection limit of the immunosensor was 1.0 × 10{sup 2} CFU/mL. The immunosensor sensitivity was 56.82 Ω/CFU·mL{sup −1}. Furthermore, the parameters affecting immunosensor response were also investigated, as follows: pH value, immunoreaction time, incubation temperature, and anti-V. cholerae O1 concentration. - Highlights: • A label-free immunosensor based on cerium oxide nanowire for Vibrio cholerae O1 detection application was developed. • A linear response was found in the range of 1.0 × 10{sup 2} CFU/mL to 1.0 × 10{sup 4} CFU/mL. • The detection limit of the immunosensor was 1.0 × 10{sup 2} CFU/mL. • The immunosensor sensitivity was 56.82 Ω/CFU.mL{sup −1}.

  7. Immunosensors Based on Single-Walled Carbon Nanotubes (SWCNT for the Detection of Deep Venous Thrombosis

    Directory of Open Access Journals (Sweden)

    Sondes BOURIGUA

    2014-05-01

    Full Text Available Thanks to their properties, Single-Walled carbon nanotubes (SWNT open a new way to the fabrication of Immunosensors with the particularity to amplify the response signal from antibody–antigen interaction and to improve the Immunosensors characteristics. In this context, two new impedimetric immunosensors were developed by immobilizing antibody on Single-Walled carbon, the later was immobilized following two ways the first consist of immobilizing the carbon nanotubes on a polypyrrole layer by adsorption and the second consist of functionalized gold with amino thiol and then immobilizing the carbon nanotubes with covalent binding. The electrical properties and the morphology of the immunosensors have been characterized respectively by Electrochemical Impedance Spectroscopy, cyclic voltammetry and Atomic Force Spectroscopy. A low detection limit for both immunosensors was determined as 1 pg/ml and linear ranges up to 10 ng/ml with polypyrrole and up to 100 ng/ml with amino thiol were obtained. Moreover, the studied Immunosensors exhibited high sensitivity, stability and reproducibility.

  8. Depleted uranium

    International Nuclear Information System (INIS)

    Huffer, E.; Nifenecker, H.

    2001-02-01

    This document deals with the physical, chemical and radiological properties of the depleted uranium. What is the depleted uranium? Why do the military use depleted uranium and what are the risk for the health? (A.L.B.)

  9. Capacitive immunosensor for C-reactive protein quantification

    KAUST Repository

    Sapsanis, Christos

    2015-08-02

    We report an agglutination-based immunosensor for the quantification of C-reactive protein (CRP). The developed immunoassay sensor requires approximately 15 minutes of assay time per sample and provides a sensitivity of 0.5 mg/L. We have measured the capacitance of interdigitated electrodes (IDEs) and quantified the concentration of added analyte. The proposed method is a label free detection method and hence provides rapid measurement preferable in diagnostics. We have so far been able to quantify the concentration to as low as 0.5 mg/L and as high as 10 mg/L. By quantifying CRP in serum, we can assess whether patients are prone to cardiac diseases and monitor the risk associated with such diseases. The sensor is a simple low cost structure and it can be a promising device for rapid and sensitive detection of disease markers at the point-of-care stage.

  10. Introduction to biosensors from electric circuits to immunosensors

    CERN Document Server

    Yoon, Jeong-Yeol

    2016-01-01

    This book equips students with a thorough understanding of various types of sensors and biosensors that can be used for chemical, biological, and biomedical applications, including but not limited to temperature sensors, strain sensor, light sensors, spectrophotometric sensors, pulse oximeter, optical fiber probes, fluorescence sensors, pH sensor, ion-selective electrodes, piezoelectric sensors, glucose sensors, DNA and immunosensors, lab-on-a-chip biosensors, paper-based lab-on-a-chip biosensors, and microcontroller-based sensors. The author treats the study of biosensors with an applications-based approach, including over 15 extensive, hands-on labs given at the end of each chapter. The material is presented using a building-block approach, beginning with the fundamentals of sensor design and temperature sensors, and ending with more complicated biosensors. New to this second edition are sections on op-amp filters, pulse oximetry, meat quality monitoring, advanced fluorescent dyes, autofluorescence, various...

  11. Scalable fabrication of immunosensors based on carbon nanotube polymer composites

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza, Ernest; Gonzalez-Guerrero, Ana B [Institut Catala de Nanotecnologia, Campus Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain); Orozco, Jahir; Jimenez-Jorquera, Cecilia; Fernandez-Sanchez, Cesar [Instituto de Microelectronica de Barcelona, CNM-IMB (CSIC), Campus Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain); Calle, Ana; Lechuga, Laura M [Instituto de Microelectronica de Madrid, CNM-IMM (CSIC), Isaac Newton 8, 28760 Tres Cantos, Madrid (Spain)], E-mail: Ernest.Mendoza.icn@uab.es

    2008-02-20

    In this work we present the fabrication and characterization of immunosensors based on polystyrene (PS)-multiwalled carbon nanotube (MWCNT) composites. The electrochemical properties of the sensors have been investigated and show that the surface area is increased upon addition of the MWCNT-PS layer. Furthermore, a plasma activation process is used to partially remove the PS and expose the MWCNTs. This results in a huge increase in the electrochemical area and opens up the possibility of binding biomolecules to the MWCNT wall. The MWCNTs have been functionalized covalently with a model antibody (rabbit IgG). The biosensors have been tested using amperometric techniques and show detection limits comparable to standard techniques such as ELISA.

  12. A SPR-based immunosensor for the detection of isoproturon.

    Science.gov (United States)

    Gouzy, Marie-Françoise; Kess, Melanie; Krämer, Petra M

    2009-02-15

    The proof of principle of a reusable surface plasmon resonance (SPR)-based immunosensor for the monitoring of isoproturon (IPU), a selective and systemic herbicide, is presented. The detecting rat monoclonal anti-isoproturon antibody (mAb IOC 7E1) was reversibly immobilized through the use of a capture mouse anti-rat (kappa-chain) monoclonal antibody (mAb TIB 172), which was covalently immobilized on the sensor chip surface. Such strategy features a controlled binding of the captured detecting antibody as well as facilitates the surface regeneration. The capture of the anti-IPU mAb by the antibody (TIB 172) coated sensor surface could be carried out up to 120 times (immobilization/regeneration cycles) without any evidence of activity loss. With a high test midpoint and a low associated SPR signal, the direct detection format was shown to be unsuitable for the routine analysis of isoproturon. However, the limit of detection (LOD) could be easily enhanced by using a strategy based on a surface competition assay, which improved all immunosensor parameters. Moreover, the sensitivity and working range of the indirect format were found to be dependent on the surface density of the anti-IPU mAb IOC 7E1. As expected for competitive formats, the lowest surface coverage (0.5 ng/mm(2)) allowed a lower detection of the herbicide isoproturon with a calculated LOD of 0.1 microg/l, an IC(50) (50% inhibition) of 5.3+/-0.6 microg/l, and a working range (20-80% inhibition) of 1.3-16.3 microg/l.

  13. Uranium conversion

    International Nuclear Information System (INIS)

    Oliver, Lena; Peterson, Jenny; Wilhelmsen, Katarina

    2006-03-01

    FOI, has performed a study on uranium conversion processes that are of importance in the production of different uranium compounds in the nuclear industry. The same conversion processes are of interest both when production of nuclear fuel and production of fissile material for nuclear weapons are considered. Countries that have nuclear weapons ambitions, with the intention to produce highly enriched uranium for weapons purposes, need some degree of uranium conversion capability depending on the uranium feed material available. This report describes the processes that are needed from uranium mining and milling to the different conversion processes for converting uranium ore concentrate to uranium hexafluoride. Uranium hexafluoride is the uranium compound used in most enrichment facilities. The processes needed to produce uranium dioxide for use in nuclear fuel and the processes needed to convert different uranium compounds to uranium metal - the form of uranium that is used in a nuclear weapon - are also presented. The production of uranium ore concentrate from uranium ore is included since uranium ore concentrate is the feed material required for a uranium conversion facility. Both the chemistry and principles or the different uranium conversion processes and the equipment needed in the processes are described. Since most of the equipment that is used in a uranium conversion facility is similar to that used in conventional chemical industry, it is difficult to determine if certain equipment is considered for uranium conversion or not. However, the chemical conversion processes where UF 6 and UF 4 are present require equipment that is made of corrosion resistant material

  14. Uranium exploration

    International Nuclear Information System (INIS)

    De Voto, R.H.

    1984-01-01

    This paper is a review of the methodology and technology that are currently being used in varying degrees in uranium exploration activities worldwide. Since uranium is ubiquitous and occurs in trace amounts (0.2 to 5 ppm) in virtually all rocks of the crust of the earth, exploration for uranium is essentially the search of geologic environments in which geologic processes have produced unusual concentrations of uranium. Since the level of concentration of uranium of economic interest is dependent on the present and future price of uranium, it is appropriate here to review briefly the economic realities of uranium-fueled power generation. (author)

  15. Electrochemical Immunosensor Based on Polythionine/Gold Nanoparticles for the Determination of Aflatoxin B1

    Directory of Open Access Journals (Sweden)

    Joseph H.O. Owino

    2008-12-01

    Full Text Available An aflatoxin B1 (AFB1 electrochemical immunosensor was developed by the immobilisation of aflatoxin B1-bovine serum albumin (AFB1-BSA conjugate on a polythionine (PTH/gold nanoparticles (AuNP-modified glassy carbon electrode (GCE. The surface of the AFB1-BSA conjugate was covered with horseradish peroxidase (HRP, in order to prevent non-specific binding of the immunosensors with ions in the test solution. The AFB1 immunosensor exhibited a quasi-reversible electrochemistry as indicated by a cyclic voltammetric (CV peak separation (ΔEp value of 62 mV. The experimental procedure for the detection of AFB1 involved the setting up of a competition between free AFB1 and the immobilised AFB1-BSA conjugate for the binding sites of free anti-aflatoxin B1 (anti-AFB1 antibody. The immunosensor’s differential pulse voltammetry (DPV responses (peak currents decreased as the concentration of free AFB1 increased within a dynamic linear range (DLR of 0.6 - 2.4 ng/mL AFB1 and a limit of detection (LOD of 0.07 ng/mL AFB1. This immunosensing procedure eliminates the need for enzyme-labeled secondary antibodies normally used in conventional ELISA–based immunosensors.

  16. Impedimetric Label-Free Immunosensor on Disposable Modified Screen-Printed Electrodes for Ochratoxin A

    Directory of Open Access Journals (Sweden)

    Francesca Malvano

    2016-06-01

    Full Text Available An impedimetric label-free immunosensor on disposable screen-printed carbon electrodes (SPCE for quantitative determination of Ochratoxin A (OTA has been developed. After modification of the SPCE surface with gold nanoparticles (AuNPs, the anti-OTA was immobilized on the working electrode through a cysteamine layer. After each coating step, the modified surfaces were characterized by cyclic voltammetry (CV and electrochemical impedance spectroscopy (EIS. The capacitance was chosen as the best parameter that describes the reproducible change in electrical properties of the electrode surface at different OTA concentrations and it was used to investigate the analytical parameters of the developed immunosensor. Under optimized conditions, the immunosensor showed a linear relationship between 0.3 and 20 ng/mL with a low detection limit of 0.25 ng/mL, making it suitable to control OTA content in many common food products. Lastly, the immunosensor was used to measure OTA in red wine samples and the results were compared with those registered with a competitive ELISA kit. The immunosensor was sensitive to OTA lower than 2 μg/kg, which represents the lower acceptable limit of OTA established by European legislation for common food products.

  17. Automated-immunosensor with centrifugal fluid valves for salivary cortisol measurement

    Directory of Open Access Journals (Sweden)

    Masaki Yamaguchi

    2014-08-01

    Full Text Available Point-of-care measurement of the stress hormone cortisol will greatly facilitate the timely diagnosis and management of stress-related disorders. We describe an automated salivary cortisol immunosensor, incorporating centrifugal fluid valves and a disposable disc-chip that allows for truncated reporting of cortisol levels (<15 min. The performance characteristics of the immunosensor are optimized through select blocking agents to prevent the non-specific adsorption of proteins; immunoglobulin G (IgG polymer for the pad and milk protein for the reservoirs and the flow channels. Incorporated centrifugal fluid valves allow for rapid and repeat washings to remove impurities from the saliva samples. An optical reader and laptop computer automate the immunoassay processes and provide easily accessible digital readouts of salivary cortisol measurements. Linear regression analysis of the calibration curve for the cortisol immunosensor showed 0.92 of coefficient of multiple determination, R2, and 38.7% of coefficient of variation, CV, for a range of salivary cortisol concentrations between 0.4 and 11.3 ng/mL. The receiver operating characteristic (ROC curve analysis of human saliva samples indicate potential utility for discriminating stress disorders and underscore potential application of the biosensor in stress disorders. The performance of our salivary cortisol immunosensor approaches laboratory based tests and allows noninvasive, quantitative, and automated analysis of human salivary cortisol levels with reporting times compatible with point-of-care applications. Keywords: Immunosensor, Centrifugal fluid valve, Automation, Cortisol, Saliva

  18. Field-Portable Immunoassay Instruments and Reagents to Measure Chelators and Mobile Forms of Uranium

    International Nuclear Information System (INIS)

    Blake, Diane A.

    2003-01-01

    The goals for the 3-year project period are (1) to test and validate the present uranium sensor and develop protocols for its use at the NABIR Field Research Center; (2) to develop new reagents that will provide superior performance for the present hand-held immunosensor; and (3) to develop new antibodies that will permit this sensor to also measure other environmental contaminants (chromium, mercury, and/or DTPA). Sensor design modifications are underway via international collaborations. New reagents that will provide superior performance for the present hand-held immunosensor are being prepared and tested. New methods have been developed, to produce recombinant forms of metal-specific monoclonal antibodies for use with the sensor. Site-directed mutagenesis experiments are underway to determine the mechanisms of binding. Immunization experiments with sheep and rabbits to develop new recombinant forms of antibodies to metal-chelate complexes (chromium, mercury, and/or DTPA) have been initiated

  19. An Amperometric Immunosensor Based on Graphene Composite Film and Protein a for Chlorpyrifos Detection

    Directory of Open Access Journals (Sweden)

    Xiangyou Wang

    2014-09-01

    Full Text Available In this paper, an immunosensor was designed for chlorpyrifos detection, which was based on graphene-multi-walled carbon nanotubes-gold nanoparticle-chitosan (GR-MWCNTs-AuNPs- CHIT nanocomposite film. Protein A (SPA can combine with gold nanoparticles, which made anti- chlorpyrifos antibody immobilized orientedly, eventually the modified immunosensor was developed for the detection of chlorpyrifos residues. Under the optimized conditions, a regression equation: y=9.5676 lgC (ng/mL +18.164 (R2=0.9976 was obtained with a detection limit as low as 0.037 ng/mL. The proposed chlorpyrifos immunosensor exhibited high reproducibility, stability, and good selectivity and regeneration, it has the potential of real sample detection.

  20. Multianalyte detection using a capillary-based flow immunosensor.

    Science.gov (United States)

    Narang, U; Gauger, P R; Kusterbeck, A W; Ligler, F S

    1998-01-01

    A highly sensitive, dual-analyte detection system using capillary-based immunosensors has been designed for explosive detection. This model system consists of two capillaries, one coated with antibodies specific for 2,4,6-trinitrotoluene (TNT) and the other specific for hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) combined into a single device. The fused silica capillaries are prepared by coating anti-TNT and anti-RDX antibodies onto the silanized inner walls using a hetero-bifunctional crosslinker. After immobilization, the antibodies are saturated with a suitable fluorophorelabeled antigen. A "T" connector is used to continuously flow the buffer solution through the individual capillaries. To perform the assay, an aliquot of TNT or RDX or a mixture of the two analytes is injected into the continuous flow stream. In each capillary, the target analyte displaces the fluorophore-labeled antigen from the binding pocket of the antibody. The labeled antigen displaced from either capillary is detected downstream using two portable spectrofluorometers. The limits of detection for TNT and RDX in the multi-analyte formate are 44 fmol (100 microliters of 0.1 ng/ml TNT solution) and 224 fmol (100 microliters of 0.5 ng/ml RDX solution), respectively. The entire assay for both analytes can be performed in less than 3 min.

  1. Development of an Electrochemical Immunosensor for Fumonisins Detection in Foods

    Science.gov (United States)

    Kadir, Mohamad Kamal Abdul; Tothill, Ibtisam E.

    2010-01-01

    An electrochemical affinity sensor for the determination of fumonisins mycotoxins (Fms) using monoclonal antibody modified screen-printed gold electrode with carbon counter and silver-silver chloride pseudo-reference electrode is reported in this work. A direct competitive enzyme-linked immunosorbent assay (ELISA) was initially developed, exhibiting a detection limit of 100 µg·L-1 for fumonisins. This was then transferred to the surface of a bare gold screen-printed electrode (SPGE) and detection was performed by chronoamperometry, monitoring the reaction of 3,3’,5,5’-Tetramethylbenzidine dihydrochloride (TMB) and hydrogen peroxide (H2O2) catalysed by HRP at −100 mV potential vs. onboard Ag-AgCl pseudo-reference electrode. The immunosensor exhibited detection limit of 5 µg·L−1 fumonisins with a dynamic range from 1 µg·L−1–1000 µg·L−1. The sensor also performed well in extracted corn samples. PMID:22069591

  2. In-line analytical instrumentation in nuclear fuel reprocessing plants

    International Nuclear Information System (INIS)

    Rao, V.K.; Bhargava, V.K.; Marathe, S.G.

    1979-01-01

    In nuclear fuel reprocessing plants where uranium and plutonium are separated from highly radioactive fission products, continuous monitoring of these constituents is helpful in many ways. Apart from quick detection of possible process malfunctions, in-line monitoring protects operating personnel from radiation hazards, reduces the cost of laboratory analysis and increases the overall efficiency of the process. A review of a proqramme of work on the design, fabrication and testing of some in-line instruments viz. gamma absorptiometer for uranium, neutron monitor for plutonium, acidity monitor for scrub nitric acid etc., their feasibility studies in the laboratory as well as in the pilot plant is presented. (auth.)

  3. Sensitive electrochemical immunosensor for α-fetoprotein based on graphene/SnO2/Au nanocomposite.

    Science.gov (United States)

    Liu, Junfeng; Lin, Guanhua; Xiao, Can; Xue, Ying; Yang, Ankang; Ren, Hongxuan; Lu, Wensheng; Zhao, Hong; Li, Xiangjun; Yuan, Zhuobin

    2015-09-15

    A label-free electrochemical immunosensor for sensitive detection of α-fetoprotein (AFP) was developed based on graphene/SnO2/Au nanocomposite. The graphene/SnO2/Au nanocomposite modified glassy carbon electrode was used to immobilize α-fetoprotein antibody (anti-AFP) and to construct the immunosensor. Results demonstrated that the peak currents of [Ru(NH3)6](3+) decreased due to the interaction between antibody and antigen on the modified electrode. Thus, a label-free immunosensor for the detection of AFP was realized by monitoring the peak current change of [Ru(NH3)6](3+). The factors influencing the performance of the immunosensor were investigated in details. Under optimal conditions, the peak currents obtained by DPV decreased linearly with the increasing AFP concentrations in the range from 0.02 to 50 ng mL(-1) with a linear coefficient of 0.9959. This electrochemical immunoassay has a low detection limit of 0.01 ng mL(-1) (S/N=3) and was successfully applied to the determination of AFP in serum samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. 3D label-free prostate specific antigen (PSA) immunosensor based on graphene-gold composites.

    Science.gov (United States)

    Jang, Hee Dong; Kim, Sun Kyung; Chang, Hankwon; Choi, Jeong-Woo

    2015-01-15

    Highly sensitive and label-free detection of the prostate specific antigen (PSA) remains a challenge in the diagnosis of prostate cancer. Here, a novel three-dimensional (3D) electrochemical immunosensor capable of sensitive and label-free detection of PSA is reported. This unique immunosensor is equipped with a highly conductive graphene (GR)-based gold (Au) composite modified electrode. The GR-based Au composite is prepared using aerosol spray pyrolysis and the morphology of the composite is the shape of a crumpled GR ball decorated with Au nanoparticles. Unlike the previous research, this novel 3D immunosensor functions very well over a broad linear range of 0-10 ng/mL with a low detection limit of 0.59 ng/mL; furthermore, it exhibits a significantly increased electron transfer and high sensitivity toward PSA. The highest rate of current change with respect to the PSA concentration is 5 μA/(ng/mL). Satisfactory selectivity, reproducibility, and stability of the 3D immunosensor are also exhibited. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Rapid Detection Technology for Pesticides Residues Based on Microelectrodes Impedance Immunosensor

    Directory of Open Access Journals (Sweden)

    Wen Ping Zhao

    2014-09-01

    Full Text Available Compared with conventional methods, electrochemical immunosensors have many advantages, such as low cost, high sensitivity, and rapid detection, and has certain prospects for realizing real-time-monitoring. In this paper, a design of portable pesticide residues detection instrument was presented based on an electrochemical impedance immunosensor. Firstly, we studied on an impedance immunosensor based on interdigitated array microelectrode (IDAM coupled with magnetic nanobeads-antibody conjugates (MNAC for the pesticide detection. Magnetic nanobeads (diameter 150 nm coated with anti-carbofuran antibodies were used for further amplification of the binding reaction between antibody and hapten (carbofuran. Secondly, in order to develop a portable pesticide residue apparatus, we designed the impedance detection electric circuit. Main work included designing and constructing of the system circuit, designing and debugging of the system software and so on. Thirdly, the apparatus was used for the standard pesticides solutions testing combined with immunosensor to test the reliability and stability. The pesticide added standard recovery was more than 70 % and the impedance test error was less than 5 %. The results showed that the proposed instrument had a good consistence compared with the traditional analytical methods. Thus, it would be a promising rapid detection instrument for pesticide residues in agricultural products.

  6. Rapid Determination of Phytophthora infestans sporangia Using a Surface Plasmon Resonance Immunosensor

    DEFF Research Database (Denmark)

    Skottrup, Peter; Nicolaisen, Mogens; Justesen, Annemarie Fejer

    2007-01-01

    Phytophthora infestans is the cause of late blight disease in potato and is an economically important pathogen worldwide. Early disease detection is important to implement disease control measures. In this study a surface plasmon resonance (SPR) immunosensor for detection of P. infestans sporangia...

  7. Feasibility of evanescent wave interferometer immunosensors for pesticide detection: chemical aspects

    NARCIS (Netherlands)

    Lechuga, L.M.; Lechuga, L.M.; Lenferink, Aufrid T.M.; Kooyman, R.P.H.; Greve, Jan

    1995-01-01

    A waveguide Mach-Zehnder Interferometer (MZI) immunosensor has been developed which can detect, in a direct way, a minimum average layer growth thickness of the analyte of 2×10−3 nm (bound mass, I′=1×10−4 δ cm−2). The design and fabrication of the sensor and the experimental set-up are aimed at

  8. Conducting polymer film-based immunosensors using carbon nanotube/antibodies doped polypyrrole

    Energy Technology Data Exchange (ETDEWEB)

    Tam, Phuong Dinh, E-mail: phuongdinhtam@gmail.com [Advanced Institute for Science and Technology (AIST), Hanoi University of Science and Technology (Viet Nam); Hieu, Nguyen Van [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (Viet Nam)

    2011-09-15

    Carbon nanotube/polypyrrole/antibodies polymer films were synthesized successfully on microelectrodes by electrochemical deposition. Electropolymerization was performed at optimal range between -0.8 and +0.8 V at a scan rate of 50 mV s{sup -1} in an electrochemical mini-cell containing monomer pyrroles, carbon nanotubes, and goat IgGs. The conducting polymer films were characterized by Fourier transform infrared spectrometry, Raman spectra, and Field emission scanning electron microscopy. And then, it was prepared for immunosensor application to determine anti-goat IgGs. The results show that a linear range between 0.05 and 0.7 {mu}g ml{sup -1} for anti-goat IgGs detection was observed for immunosensor, a detection limit as low as 0.05 {mu}g ml{sup -1} and a response time of 1 min. The effect parameters of electropolymerization process on immunosensor response are also studied. It found that the immunosensor well active in 1.5 mg ml{sup -1} CNT concentration, 2.5 mM pyrrole, 10 {mu}g ml{sup -1} goat IgGs.

  9. Magnetic beads-based electrochemical immunosensor for monitoring allergenic food proteins

    Czech Academy of Sciences Publication Activity Database

    Čadková, M.; Metelka, R.; Holubová, L.; Horák, Daniel; Dvořáková, V.; Bílková, Z.; Korecká, L.

    2015-01-01

    Roč. 484, 1 September (2015), s. 4-8 ISSN 0003-2697 R&D Projects: GA ČR GAP206/12/0381 Institutional support: RVO:61389013 Keywords : electrochemical immunosensor * magnetic particles * ovalbumin Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.243, year: 2015

  10. Sensitive electrochemical immunosensor based on three-dimensional nanostructure gold electrode

    Directory of Open Access Journals (Sweden)

    Zhong G

    2015-03-01

    Full Text Available Guangxian Zhong,1,2,* Ruilong Lan,3,* Wenxin Zhang,1,4 Feihuan Fu,5 Yiming Sun,1,4 Huaping Peng,1,4 Tianbin Chen,3 Yishan Cai,6 Ailin Liu,1,4 Jianhua Lin,2 Xinhua Lin1,4 1Department of Pharmaceutical Analysis, Faculty of Pharmacy, Fujian Medical University, 2Department of Orthopaedics, 3The Centralab, First Affiliated Hospital of Fujian Medical University, 4Nano Medical Technology Research Institute, Fujian Medical University, Fuzhou, 5Department of Endocrinology, The County Hospital of Anxi, Anxi, 6Fujian International Travel Healthcare Center, Fujian Entry-Exit Inspection and Quarantine Bureau, Fuzhou, People’s Republic of China *These authors contributed equally to this work Abstract: A sensitive electrochemical immunosensor was developed for detection of alpha-fetoprotein (AFP based on a three-dimensional nanostructure gold electrode using a facile, rapid, “green” square-wave oxidation-reduction cycle technique. The resulting three-dimensional gold nanocomposites were characterized by scanning electron microscopy and cyclic voltammetry. A “sandwich-type” detection strategy using an electrochemical immunosensor was employed. Under optimal conditions, a good linear relationship between the current response signal and the AFP concentrations was observed in the range of 10–50 ng/mL with a detection limit of 3 pg/mL. This new immunosensor showed a fast amperometric response and high sensitivity and selectivity. It was successfully used to determine AFP in a human serum sample with a relative standard deviation of <5% (n=5. The proposed immunosensor represents a significant step toward practical application in clinical diagnosis and monitoring of prognosis. Keywords: electrochemical immunosensors, three-dimensional nanostructure gold electrode, square-wave oxidation-reduction cycle, alpha-fetoprotein 

  11. Copper-doped titanium dioxide nanoparticles as dual-functional labels for fabrication of electrochemical immunosensors.

    Science.gov (United States)

    Zhang, Sen; Ma, Hongmin; Yan, Liangguo; Cao, Wei; Yan, Tao; Wei, Qin; Du, Bin

    2014-09-15

    Constructions of versatile electroactive labels are key issues in the development of electrochemical immunosensors. In this study, copper-doped titanium dioxide nanoparticle (Cu@TiO2) was synthesized and used as labels for fabrication of sandwich-type electrochemical immunosensors on glassy carbon electrode (GCE). Due to the presence of copper ions, Cu@TiO2 shows a strong response current when coupled to an electrode. The prepared nanocomposite also shows high electrocatalytic activity towards reduction of hydrogen peroxide (H2O2). The dual functionality of Cu@TiO2 enables the fabrication of immunosensor using different detection modes, that is, square wave voltammetry (SWV) or chronoamperometry (CA). While Cu@TiO2 was used as labels of secondary antibodies (Ab2), carboxyl functionalized graphene oxide (CFGO) was used as electrode materials to immobilize primary antibodies (Ab1). Using human immunoglobulin G (IgG) as a model analyte, the immunosensor shows high sensitivity, acceptable stability and good reproducibility for both detection modes. Under optimal conditions, a linear range from 0.1 pg/mL to 100 ng/mL with a detection limit of 0.052 pg/mL was obtained for SWV analysis. For CA analysis, a wider linear range from 0.01 pg/mL to 100 ng/mL and a lower detection limit of 0.0043 pg/mL were obtained. The proposed metal ion-based enzyme-free and noble metal-free immunosensor may have promising applications in clinical diagnoses and many other fields. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Czechoslovak uranium

    International Nuclear Information System (INIS)

    Pluskal, O.

    1992-01-01

    Data and knowledge related to the prospecting, mining, processing and export of uranium ores in Czechoslovakia are presented. In the years between 1945 and January 1, 1991, 98,461.1 t of uranium were extracted. In the period 1965-1990 the uranium industry was subsidized from the state budget to a total of 38.5 billion CSK. The subsidies were put into extraction, investments and geologic prospecting; the latter was at first, ie. till 1960 financed by the former USSR, later on the two parties shared costs on a 1:1 basis. Since 1981 the prospecting has been entirely financed from the Czechoslovak state budget. On Czechoslovak territory uranium has been extracted from deposits which may be classified as vein-type deposits, deposits in uranium-bearing sandstones and deposits connected with weathering processes. The future of mining, however, is almost exclusively being connected with deposits in uranium-bearing sandstones. A brief description and characteristic is given of all uranium deposits on Czechoslovak territory, and the organization of uranium mining in Czechoslovakia is described as is the approach used in the world to evaluate uranium deposits; uranium prices and actual resources are also given. (Z.S.) 3 figs

  13. Uranium ores

    International Nuclear Information System (INIS)

    Poty, B.; Roux, J.

    1998-01-01

    The processing of uranium ores for uranium extraction and concentration is not much different than the processing of other metallic ores. However, thanks to its radioactive property, the prospecting of uranium ores can be performed using geophysical methods. Surface and sub-surface detection methods are a combination of radioactive measurement methods (radium, radon etc..) and classical mining and petroleum prospecting methods. Worldwide uranium prospecting has been more or less active during the last 50 years, but the rise of raw material and energy prices between 1970 and 1980 has incited several countries to develop their nuclear industry in order to diversify their resources and improve their energy independence. The result is a considerable increase of nuclear fuels demand between 1980 and 1990. This paper describes successively: the uranium prospecting methods (direct, indirect and methodology), the uranium deposits (economical definition, uranium ores, and deposits), the exploitation of uranium ores (use of radioactivity, radioprotection, effluents), the worldwide uranium resources (definition of the different categories and present day state of worldwide resources). (J.S.)

  14. Uranium market

    International Nuclear Information System (INIS)

    Rubini, L.A.; Asem, M.A.D.

    1990-01-01

    The historical development of the uranium market is present in two periods: The initial period 1947-1970 and from 1970 onwards, with the establishment of a commercial market. The world uranium requirements are derived from the corresponding forecast of nuclear generating capacity, with, particular emphasis to the brazilian requirements. The forecast of uranium production until the year 2000 is presented considering existing inventories and the already committed demand. The balance between production and requirements is analysed. Finally the types of contracts currently being used and the development of uranium prices in the world market are considered. (author)

  15. Uranium enrichment

    International Nuclear Information System (INIS)

    1990-01-01

    This report looks at the following issues: How much Soviet uranium ore and enriched uranium are imported into the United States and what is the extent to which utilities flag swap to disguise these purchases? What are the U.S.S.R.'s enriched uranium trading practices? To what extent are utilities required to return used fuel to the Soviet Union as part of the enriched uranium sales agreement? Why have U.S. utilities ended their contracts to buy enrichment services from DOE?

  16. Uranium mining

    International Nuclear Information System (INIS)

    Lange, G.

    1975-01-01

    The winning of uranium ore is the first stage of the fuel cycle. The whole complex of questions to be considered when evaluating the profitability of an ore mine is shortly outlined, and the possible mining techniques are described. Some data on uranium mining in the western world are also given. (RB) [de

  17. Uranium enrichment

    International Nuclear Information System (INIS)

    1989-01-01

    GAO was asked to address several questions concerning a number of proposed uranium enrichment bills introduced during the 100th Congress. The bill would have restructured the Department of Energy's uranium enrichment program as a government corporation to allow it to compete more effectively in the domestic and international markets. Some of GAO's findings discussed are: uranium market experts believe and existing market models show that the proposed DOE purchase of a $750 million of uranium from domestic producers may not significantly increase production because of large producer-held inventories; excess uranium enrichment production capacity exists throughout the world; therefore, foreign producers are expected to compete heavily in the United States throughout the 1990s as utilities' contracts with DOE expire; and according to a 1988 agreement between DOE's Offices of Nuclear Energy and Defense Programs, enrichment decommissioning costs, estimated to total $3.6 billion for planning purposes, will be shared by the commercial enrichment program and the government

  18. Uranium resources

    International Nuclear Information System (INIS)

    1976-01-01

    This is a press release issued by the OECD on 9th March 1976. It is stated that the steep increases in demand for uranium foreseen in and beyond the 1980's, with doubling times of the order of six to seven years, will inevitably create formidable problems for the industry. Further substantial efforts will be needed in prospecting for new uranium reserves. Information is given in tabular or graphical form on the following: reasonably assured resources, country by country; uranium production capacities, country by country; world nuclear power growth; world annual uranium requirements; world annual separative requirements; world annual light water reactor fuel reprocessing requirements; distribution of reactor types (LWR, SGHWR, AGR, HWR, HJR, GG, FBR); and world fuel cycle capital requirements. The information is based on the latest report on Uranium Resources Production and Demand, jointly issued by the OECD's Nuclear Energy Agency (NEA) and the International Atomic Energy Agency. (U.K.)

  19. Uranium supply and demand

    Energy Technology Data Exchange (ETDEWEB)

    Spriggs, M J

    1976-01-01

    Papers were presented on the pattern of uranium production in South Africa; Australian uranium--will it ever become available; North American uranium resources, policies, prospects, and pricing; economic and political environment of the uranium mining industry; alternative sources of uranium supply; whither North American demand for uranium; and uranium demand and security of supply--a consumer's point of view. (LK)

  20. Design, fabrication and characterization of a two-step released silicon dioxide piezoresistive microcantilever immunosensor

    International Nuclear Information System (INIS)

    Zhou, Youzheng; Wang, Zheyao; Wang, Chaonan; Ruan, Wenzhou; Liu, Litian

    2009-01-01

    This paper presents the design, fabrication and characterization of a silicon dioxide piezoresistive microcantilever immunosensor fabricated on silicon-on-insulator (SOI) wafers. The microcantilever consists of two strips of single crystalline silicon piezoresistors sandwiched in between two silicon dioxide layers. A theoretical model for the laminated microcantilever with a discontinuous layer is deduced using classic laminated beam theory. A two-step release method combining anisotropic and isotropic etching is developed to suspend the microcantilever, and the fabrication results show an excellent yield. The residual stress-induced free bending of the microcantilever and the stress caused by self-heating of the piezoresistors are discussed. The microcantilever sensor is characterized as an immunosensor using specific binding of antigen and antibody. These methods and some conclusions are also applicable to the development of other piezoresistive sensors that use laminated structures

  1. A Fumonisins Immunosensor Based on Polyanilino-Carbon Nanotubes Doped with Palladium Telluride Quantum Dots

    Science.gov (United States)

    Masikini, Milua; Mailu, Stephen N.; Tsegaye, Abebaw; Njomo, Njagi; Molapo, Kerileng M.; Ikpo, Chinwe O.; Sunday, Christopher Edozie; Rassie, Candice; Wilson, Lindsay; Baker, Priscilla G. L.; Iwuoha, Emmanuel I.

    2015-01-01

    An impedimetric immunosensor for fumonisins was developed based on poly(2,5-dimethoxyaniline)-multi-wall carbon nanotubes doped with palladium telluride quantum dots onto a glassy carbon surface. The composite was assembled by a layer-by-layer method to form a multilayer film of quantum dots (QDs) and poly(2,5-dimethoxyaniline)-multi-wall carbon nanotubes (PDMA-MWCNT). Preparation of the electrochemical immunosensor for fumonisins involved drop-coating of fumonisins antibody onto the composite modified glassy carbon electrode. The electrochemical impedance spectroscopy response of the FB1 immunosensor (GCE/PT-PDMA-MWCNT/anti-Fms-BSA) gave a linear range of 7 to 49 ng L−1 and the corresponding sensitivity and detection limits were 0.0162 kΩ L ng−1 and 0.46 pg L−1, respectively, hence the limit of detection of the GCE/PT-PDMA-MWCNT immunosensor for fumonisins in corn certified material was calculated to be 0.014 and 0.011 ppm for FB1, and FB2 and FB3, respectively. These results are lower than those obtained by ELISA, a provisional maximum tolerable daily intake (PMTDI) for fumonisins (the sum of FB1, FB2, and FB3) established by the Joint FAO/WHO expert committee on food additives and contaminants of 2 μg kg−1 and the maximum level recommended by the U.S. Food and Drug Administration (FDA) for protection of human consumption (2–4 mg L−1). PMID:25558993

  2. Nanobody-Based Apolipoprotein E Immunosensor for Point-of-Care Testing.

    Science.gov (United States)

    Ren, Xiang; Yan, Junrong; Wu, Dan; Wei, Qin; Wan, Yakun

    2017-09-22

    Alzheimer's disease (AD) biomarkers can reflect the neurochemical indicators used to estimate the risk in clinical nephrology. Apolipoprotein E (ApoE) is an early biomarker for AD in clinical diagnosis. In this research, through bactrian camel immunization, lymphocyte isolation, RNA extraction, and library construction, ApoE-specific Nbs with high affinity were successfully separated from an immune phage display nanobody library. Herein, a colorimetric immunosensor was developed for the point-of-care testing of ApoE by layer-by-layer nanoassembly techniques and novel nanobodies (Nbs). Using highly oriented Nbs as the capture and detection antibodies, an on-site immunosensor was developed by detecting the mean gray value of fade color due to the glutaraldehyde@3-aminopropyltrimethoxysilane oxidation by H 2 O 2 . The detection limit of AopE is 0.42 pg/mL, and the clinical analysis achieves a good performance. The novel easily operated immunosensor may have potential application in the clinical diagnosis and real-time monitoring for AD.

  3. Label-free immunosensor based on Pd nanoplates for amperometric immunoassay of alpha-fetoprotein.

    Science.gov (United States)

    Wang, Huan; Li, He; Zhang, Yihe; Wei, Qin; Ma, Hongmin; Wu, Dan; Li, Yan; Zhang, Yong; Du, Bin

    2014-03-15

    In this paper, Pd nanoplates were used as a kind of electrode materials for fabrication of an electrochemical immunosensor, which was applied for detection of cancer biomarker alpha-fetoprotein (AFP). Thanks to the unique structure and properties of Pd nanoplates, the antibody of AFP (Ab) was effectively immobilized onto the surface of the Pd nanoplates modified glassy carbon electrode (GCE). Moreover, the good electrochemical properties of Pd nanoplates greatly improved the electronic transmission rate and enhanced the electrochemical signal, which led to an increase of the detection sensitivity. Based on the specific antibody-antigen interaction, a label-free immunosensor based on Pd nanoplates was developed for sensing of AFP. The current method allows us to detect AFP over a wide concentration range from 0.01 to 75.0 ng/mL with a detection limit of 4 pg/mL. The proposed immunosensor has been used to determine AFP in human serum with satisfactory results. © 2013 Elsevier B.V. All rights reserved.

  4. A disposable electrochemical immunosensor for prolactin involving affinity reaction on streptavidin-functionalized magnetic particles

    International Nuclear Information System (INIS)

    Moreno-Guzman, Maria; Gonzalez-Cortes, Araceli; Yanez-Sedeno, Paloma; Pingarron, Jose M.

    2011-01-01

    A novel electrochemical immunosensor was developed for the determination of the hormone prolactin. The design involved the use of screen-printed carbon electrodes and streptavidin-functionalized magnetic particles. Biotinylated anti-prolactin antibodies were immobilized onto the functionalized magnetic particles and a sandwich-type immunoassay involving prolactin and anti-prolactin antibody labelled with alkaline phosphatase was employed. The resulting bio-conjugate was trapped on the surface of the screen-printed electrode with a small magnet and prolactin quantification was accomplished by differential pulse voltammetry of 1-naphtol formed in the enzyme reaction using 1-naphtyl phosphate as alkaline phosphatase substrate. All variables involved in the preparation of the immunosensor and in the electrochemical detection step were optimized. The calibration plot for prolactin exhibited a linear range between 10 and 2000 ng mL -1 with a slope value of 7.0 nA mL ng -1 . The limit of detection was 3.74 ng mL -1 . Furthermore, the modified magnetic beads-antiprolactin conjugates showed an excellent stability. The immunosensor exhibited also a high selectivity with respect to other hormones. The analytical usefulness of the immnunosensor was demonstrated by analyzing human sera spiked with prolactin at three different concentration levels.

  5. A disposable electrochemical immunosensor for prolactin involving affinity reaction on streptavidin-functionalized magnetic particles

    Energy Technology Data Exchange (ETDEWEB)

    Moreno-Guzman, Maria; Gonzalez-Cortes, Araceli [Department of Analytical Chemistry, Faculty of Chemistry, University Computense of Madrid, 28040 Madrid (Spain); Yanez-Sedeno, Paloma, E-mail: yseo@quim.ucm.es [Department of Analytical Chemistry, Faculty of Chemistry, University Computense of Madrid, 28040 Madrid (Spain); Pingarron, Jose M. [Department of Analytical Chemistry, Faculty of Chemistry, University Computense of Madrid, 28040 Madrid (Spain)

    2011-04-29

    A novel electrochemical immunosensor was developed for the determination of the hormone prolactin. The design involved the use of screen-printed carbon electrodes and streptavidin-functionalized magnetic particles. Biotinylated anti-prolactin antibodies were immobilized onto the functionalized magnetic particles and a sandwich-type immunoassay involving prolactin and anti-prolactin antibody labelled with alkaline phosphatase was employed. The resulting bio-conjugate was trapped on the surface of the screen-printed electrode with a small magnet and prolactin quantification was accomplished by differential pulse voltammetry of 1-naphtol formed in the enzyme reaction using 1-naphtyl phosphate as alkaline phosphatase substrate. All variables involved in the preparation of the immunosensor and in the electrochemical detection step were optimized. The calibration plot for prolactin exhibited a linear range between 10 and 2000 ng mL{sup -1} with a slope value of 7.0 nA mL ng{sup -1}. The limit of detection was 3.74 ng mL{sup -1}. Furthermore, the modified magnetic beads-antiprolactin conjugates showed an excellent stability. The immunosensor exhibited also a high selectivity with respect to other hormones. The analytical usefulness of the immnunosensor was demonstrated by analyzing human sera spiked with prolactin at three different concentration levels.

  6. Nanoparticle-based immunosensor with apoferritin templated metallic phosphate label for quantification of phosphorylated acetylcholinesterase

    International Nuclear Information System (INIS)

    Du, Dan; Chen, Aiqiong; Xie, Yunying; Zhang, Aidong; Lin, Yuehe

    2011-01-01

    A new sandwich-like electrochemical immunosensor has been developed for quantification of organophosphorylated acetylcholinesterase (OP-AChE), an exposure biomarker of organophosphate pesticides and nerve agents. Zirconia nanoparticles (ZrO2 NPs) were anchored on a screen printed electrode (SPE) to preferably capture OP-AChE adducts by metal chelation with phospho-moieties, which was selectively recognized by lead phosphate-apoferritin labeled anti-AChE antibody (LPA-anti-AChE). The sandwich-like immunoreactions were performed among ZrO2 NPs, OP-AChE and LPA-anti-AChE to form ZrO2/OP-AChE/LPA-anti-AChE complex and the released lead ions were detected on a disposable SPE. The binding affinity was investigated by both square wave voltammetry (SWV) and quartz crystal microbalance (QCM) measurements. The proposed immunosensor yielded a linear response current over a broad OP-AChE concentrations range from 0.05 nM to 10 nM, with detection limit of 0.02 nM, which has enough sensitivity for monitoring of low-dose exposure to OPs. This method avoids the drawback of unavailability of commercial OP-specific antibody as well as amplifies detection signal by using apoferritin encoded metallic phosphate nanoparticle tags. This nanoparticle-based immunosensor offers a new method for rapid, sensitive, selective and inexpensive quantification of phosphorylated adducts for monitoring of OP pesticides and nerve agents exposures.

  7. Detection of Explosives in a Dynamic Marine Environment Using a Moored TNT Immunosensor

    Directory of Open Access Journals (Sweden)

    Paul T. Charles

    2014-02-01

    Full Text Available A field demonstration and longevity assessment for long-term monitoring of the explosive 2,4,6-trinitrotoluene (TNT in a marine environment using an anti-TNT microfluidic immunosensor is described. The TNT immunosensor is comprised of a microfluidic device with 39 parallel microchannels (2.5 cm × 250 µm × 500 µm, L × W × D fabricated in poly(methylmethacrylate (PMMA, then chemically functionalized with antibodies possessing a high affinity for TNT. Synthesized fluorescence reporter complexes used in a displacement-based assay format were used for TNT identification. For field deployment the TNT immunosensor was configured onto a submersible moored steel frame along with frame controller, pumps and TNT plume generator and deployed pier side for intermittent plume sampling of TNT (1h increments. Under varying current and tidal conditions trace levels of TNT in natural seawater were detected over an extended period (>18 h. Overnight operation and data recording was monitored via a web interface.

  8. Screen Printed Carbon Electrode Based Electrochemical Immunosensor for the Detection of Dengue NS1 Antigen

    Directory of Open Access Journals (Sweden)

    Om Parkash

    2014-11-01

    Full Text Available An electrochemical immunosensor modified with the streptavidin/biotin system on screen printed carbon electrodes (SPCEs for the detection of the dengue NS1 antigen was developed in this study. Monoclonal anti-NS1 capture antibody was immobilized on streptavidin-modified SPCEs to increase the sensitivity of the assay. Subsequently, a direct sandwich enzyme linked immunosorbent assay (ELISA format was developed and optimized. An anti-NS1 detection antibody conjugated with horseradish peroxidase enzyme (HRP and 3,3,5,5'-tetramethybezidine dihydrochloride (TMB/H2O2 was used as an enzyme mediator. Electrochemical detection was conducted using the chronoamperometric technique, and electrochemical responses were generated at −200 mV reduction potential. The calibration curve of the immunosensor showed a linear response between 0.5 µg/mL and 2 µg/mL and a detection limit of 0.03 µg/mL. Incorporation of a streptavidin/biotin system resulted in a well-oriented antibody immobilization of the capture antibody and consequently enhanced the sensitivity of the assay. In conclusion, this immunosensor is a promising technology for the rapid and convenient detection of acute dengue infection in real serum samples.

  9. Nanoparticle-based immunosensor with apoferritin templated metallic phosphate label for quantification of phosphorylated acetylcholinesterase

    Energy Technology Data Exchange (ETDEWEB)

    Du, Dan; Chen, Aiqiong; Xie, Yunying; Zhang, Aidong; Lin, Yuehe

    2011-05-15

    A new sandwich-like electrochemical immunosensor has been developed for quantification of organophosphorylated acetylcholinesterase (OP-AChE), an exposure biomarker of organophosphate pesticides and nerve agents. Zirconia nanoparticles (ZrO2 NPs) were anchored on a screen printed electrode (SPE) to preferably capture OP-AChE adducts by metal chelation with phospho-moieties, which was selectively recognized by lead phosphate-apoferritin labeled anti-AChE antibody (LPA-anti-AChE). The sandwich-like immunoreactions were performed among ZrO2 NPs, OP-AChE and LPA-anti-AChE to form ZrO2/OP-AChE/LPA-anti-AChE complex and the released lead ions were detected on a disposable SPE. The binding affinity was investigated by both square wave voltammetry (SWV) and quartz crystal microbalance (QCM) measurements. The proposed immunosensor yielded a linear response current over a broad OP-AChE concentrations range from 0.05 nM to 10 nM, with detection limit of 0.02 nM, which has enough sensitivity for monitoring of low-dose exposure to OPs. This method avoids the drawback of unavailability of commercial OP-specific antibody as well as amplifies detection signal by using apoferritin encoded metallic phosphate nanoparticle tags. This nanoparticle-based immunosensor offers a new method for rapid, sensitive, selective and inexpensive quantification of phosphorylated adducts for monitoring of OP pesticides and nerve agents exposures.

  10. Liver Cancer Detection by a Simple, Inexpensive and Effective Immunosensor with Zinc Oxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    Congo Tak-Shing Ching

    2015-11-01

    Full Text Available Regular monitoring of blood α-fetoprotein (AFP and/or carcino-embryonic antigen (CEA levels is important for the routine screening of liver cancer. However, AFP and CEA have a much lower specificity than des-γ-carboxyprothrombin (DCP to detect liver cancer. Therefore, the study reported here was designed, to develop a screen-printed DCP immunosensor incorporating zinc oxide nanoparticles, for accurate determination of DCP. The designed immunosensor shows low detection limits for the detection of DCP: 0.440 ng/mL (based on impedance measurement, 0.081 ng/mL (based on real part of impedance measurement and 0.078 ng/mL (based on imaginary part of impedance measurement, within the range of 3.125 ng/mL to 2000 ng/mL. In addition, there was little interference to DCP determination by molecules such as Na+, K+, Ca2+, Cl−, glucose, urea, and uric acid. It is therefore concluded that the DCP immunosensor developed and reported here is simple, inexpensive and effective, and shows promise in the rapid screening of early-stage liver cancer at home with a point-of-care approach.

  11. Towards an Electrochemical Immunosensor System with Temperature Control for Cytokine Detection.

    Science.gov (United States)

    Metzner, Julia; Luckert, Katrin; Lemuth, Karin; Hämmerle, Martin; Moos, Ralf

    2018-04-24

    The cytokine interleukin-13 (IL-13) plays a major role in airway inflammation and is a target of new anti-asthmatic drugs. Hence, IL-13 determination could be interesting in assessing therapy success. Thus, in this work an electrochemical immunosensor for IL-13 was developed and integrated into a fluidic system with temperature control for read-out. Therefore, two sets of results are presented. First, the sensor was set up in sandwich format on single-walled carbon nanotube electrodes and was read out by applying the hydrogen peroxide⁻hydroquinone⁻horseradish peroxidase (HRP) system. Second, a fluidic system was built up with an integrated heating function realized by Peltier elements that allowed a temperature-controlled read-out of the immunosensor in order to study the influence of temperature on the amperometric read-out. The sensor was characterized at the temperature optimum of HRP at 30 °C and at 12 °C as a reference for lower performance. These results were compared to a measurement without temperature control. At the optimum operation temperature of 30 °C, the highest sensitivity (slope) was obtained compared to lower temperatures and a limit of detection of 5.4 ng/mL of IL-13 was calculated. Taken together, this approach is a first step towards an automated electrochemical immunosensor platform and shows the potential of a temperature-controlled read-out.

  12. Simple and suitable immunosensor for β-lactam antibiotics analysis in real matrixes: milk, serum, urine.

    Science.gov (United States)

    Merola, Giovanni; Martini, Elisabetta; Tomassetti, Mauro; Campanella, Luigi

    2015-03-15

    The anti-penicillin G was conjugated to avidin-peroxidase and biotin to obtain immunogen and competitor which were then used to develop a competitive immunosensor assay for the detection of penicillin G and other β-lactam antibiotics, with Kaff values of the order of 10(8) M(-1). The new immunosensor appears to afford a number of advantages in terms of sensitivity, possibility of "in situ" analysis, but especially of simplicity and lower costs, compared with other existing devices, or different chemical instrumental methods reported in the literature and used for the analysis of β-lactam compounds. Satisfactory results were found in the analysis of real matrixes and good recoveries were obtained by applying the standard addition method to spiked milk, urine, serum and drug samples. The new device uses an amperometric electrode for hydrogen peroxide as transducer, the BSA-penicillin G immobilized on polymeric membrane overlapping the amperometric transducer and the peroxidase enzyme as marker. It proved to be highly sensitive, inexpensive and easily reproducible; LOD was of the order of 10(-11)M. Lastly, the new immunosensor displayed low selectivity versus the entire class of β-lactam antibiotics and higher selectivity toward other classes of non-β-lactam antibiotics. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Amperometric Immunosensor Based on a Protein A/Deposited Gold Nanocrystals Modified Electrode for Carbofuran Detection

    Directory of Open Access Journals (Sweden)

    Xia Sun

    2011-12-01

    Full Text Available In this paper, an amperometric immunosensor modified with protein A/deposited gold nanocrystals (DpAu was developed for the ultrasensitive detection of carbofuran residues. First, DpAu were electrodeposited onto the Au electrode surface to absorb protein A (PA and improve the electrode conductivity. Then PA was dropped onto the surface of DpAu film, used for binding antibody Fc fragments. Next, anti-carbofuran monoclonal antibody was immobilized on the PA modified electrode. Finally, bovine serum albumin (BSA was employed to block the possible remaining active sites avoiding any nonspecific adsorption. The fabrication procedure of the immunosensor was characterized by electrochemical impedance spectroscopy (EIS and cyclic voltammetry (CV, respectively. With the excellent electroconductivity of DpAu and the PA’s oriented immobilization of antibodies, a highly efficient immuno-reaction and detection sensitivity could be achieved. The influences of the electrodeposition time of DpAu, pH of the detection solution and incubation time on the current response of the fabricated immunosensor were investigated. Under optimized conditions, the current response was proportional to the concentration of carbofuran which ranged from 1 to 100 ng/mL and 100 ng/mL to 100 μg/mL. The detection limit was 0.1924 ng/mL. The proposed carbofuran immnuosensor exhibited high specificity, reproducibility, stability and regeneration performance, which may open a new door for ultrasensitive detection of carbofuran residues in vegetables and fruits.

  14. Temperature dependence of immunoreactions using shear horizontal surface acoustic wave immunosensors

    Science.gov (United States)

    Kogai, Takashi; Yatsuda, Hiromi; Kondoh, Jun

    2017-07-01

    In this paper, the temperature dependence of immunoreactions, which are antibody-antigen reactions, on a shear horizontal surface acoustic wave (SH-SAW) immunosensor is described. The immunosensor is based on a reflection-type delay line on a 36° Y-cut 90° X-propagation quartz substrate, where the delay line is composed of a floating electrode unidirectional transducer (FEUDT), a grating reflector, and a sensing area between them. In order to evaluate the temperature dependence of immunoreactions, human serum albumin (HSA) antigen-antibody reactions are investigated. The SH-SAW immunosensor chip is placed in a thermostatic chamber and the changes in the SH-SAW velocity resulting from the immunoreactions are measured at different temperatures. As a result, it is observed that the HSA immunoreactions are influenced by the ambient temperature and that higher temperatures provide more active reactions. In order to analyze the immunoreactions, an analytical approach using an exponential fitting method for changes in SH-SAW velocity is employed.

  15. Uranium, depleted uranium, biological effects; Uranium, uranium appauvri, effets biologiques

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    Physicists, chemists and biologists at the CEA are developing scientific programs on the properties and uses of ionizing radiation. Since the CEA was created in 1945, a great deal of research has been carried out on the properties of natural, enriched and depleted uranium in cooperation with university laboratories and CNRS. There is a great deal of available data about uranium; thousands of analyses have been published in international reviews over more than 40 years. This presentation on uranium is a very brief summary of all these studies. (author)

  16. Uranium toxicology

    International Nuclear Information System (INIS)

    Ferreyra, Mariana D.; Suarez Mendez, Sebastian

    1997-01-01

    In this paper are presented the methods and procedures optimized by the Nuclear Regulatory Authority (ARN) for the determination of: natural uranium mass, activity of enriched uranium in samples of: urine, mucus, filters, filter heads, rinsing waters and Pu in urine, adopted and in some cases adapted, by the Environmental Monitoring and Internal Dosimetry Laboratory. The analyzed material corresponded to biological and environmental samples belonging to the staff professionally exposed that work in plants of the nuclear fuel cycle. For a better comprehension of the activities of this laboratory, it is included a brief description of the uranium radiochemical toxicity and the limits internationally fixed to preserve the workers health

  17. Comparison between a Direct-Flow SPR Immunosensor for Ampicillin and a Competitive Conventional Amperometric Device: Analytical Features and Possible Applications to Real Samples

    Science.gov (United States)

    Tomassetti, Mauro; Merola, Giovanni; Martini, Elisabetta; Campanella, Luigi; Sanzò, Gabriella; Favero, Gabriele; Mazzei, Franco

    2017-01-01

    In this research, we developed a direct-flow surface plasmon resonance (SPR) immunosensor for ampicillin to perform direct, simple, and fast measurements of this important antibiotic. In order to better evaluate the performance, it was compared with a conventional amperometric immunosensor, working with a competitive format with the aim of finding out experimental real advantages and disadvantages of two respective methods. Results showed that certain analytical features of the new SPR immunodevice, such as the lower limit of detection (LOD) value and the width of the linear range, are poorer than those of a conventional amperometric immunosensor, which adversely affects the application to samples such as natural waters. On the other hand, the SPR immunosensor was more selective to ampicillin, and measurements were more easily and quickly attained compared to those performed with the conventional competitive immunosensor. PMID:28394296

  18. A novel immunosensor for Enterobacter sakazakii based on multiwalled carbon nanotube/ionic liquid/thionine modified electrode

    International Nuclear Information System (INIS)

    Zhang Xiao; Dou Wenchao; Zhan Xuejia; Zhao Guangying

    2012-01-01

    Highlights: ► Constructed a novel immunosensor using MWCNT/[BMIM]PF 6 /thionine for E. sakazakii. ► Optimum conditions for the detection of E. sakazakii were investigated. ► The properties of proposed immunosensor were studied by AFM and CVs. ► The biosensor exhibited good specificity, reproducibility, stability and accuracy. - Abstract: A novel immunosensor for Enterobacter sakazakii (E. sakazakii) based on screen-printed carbon electrode (SPCE) modified by multiwalled carbon nanotube (MWCNT), 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF 6 ) and thionine (Thi) was developed for the first time. The surface morphologies of modified electrodes were characterized by means of atomic force microscope (AFM). The electrochemical performance of the immunosensor was evaluated by cyclic voltammetry. Horseradish peroxidase labeled antibody to E. sakazakii in [BMIM]PF 6 showed high activity and stability. Under optimal conditions, E. sakazakii could be detected in range of 10 3 –10 9 CFU/ml with detection limit of 7.7 × 10 1 CFU/ml. The proposed immunosensor exhibited excellent long-time storage stability and had potential use in clinical immunoassay of E. sakazakii.

  19. An ultrasensitive electrochemical immunosensor for the detection of prostate-specific antigen based on conductivity nanocomposite with halloysite nanotubes.

    Science.gov (United States)

    Li, Yueyuan; Khan, Malik Saddam; Tian, Lihui; Liu, Li; Hu, Lihua; Fan, Dawei; Cao, Wei; Wei, Qin

    2017-05-01

    A sensitive label-free amperometric electrochemical immunosensor for detection of prostate-specific antigen (PSA) was proposed in this work. The nanocomposite of halloysite nanotubes with polypyrrole shell and palladium nanoparticles (HNTs@PPy-Pd) was used as a novel signal label. The HNTs with adequate hydroxyl groups are economically available raw materials. PPy, as an electrically conducting polymer material, can be absorbed to the surface of HNTs by in situ oxidative polymerization of the pyrrole monomer and form a shell on the HNTs. The shell of PPy could not only improve the conductivity of the nanocomposite but also absorb large amounts of Pd nanoparticles (NPs). The Pd NPs with high electrocatalytic activity toward the reduction of H 2 O 2 and the HNTs@PPy-Pd nanocomposite as the analytical signal label could improve the sensitivity of the immunosensor. Under optimal conditions, the immunosensor showed a low detection limit (0.03 pg/mL) and a wide linear range (0.0001 to 25 ng/mL) of PSA. Moreover, its merits such as good selectivity, acceptable reproducibility, and stability indicate that the fabricated immunosensor has a promising application potential in clinical diagnosis. Graphical Abstract A new label-free amperometric electrochemical immunosensor based on HNTs@PPy-Pd nanocomposite for quantitative detection of PSA.

  20. Electrochemical immunosensor with nanocellulose-Au composite assisted multiple signal amplification for detection of avian leukosis virus subgroup J.

    Science.gov (United States)

    Liu, Chao; Dong, Jing; Waterhouse, Geoffrey I N; Cheng, Ziqiang; Ai, Shiyun

    2018-03-15

    A sensitive sandwich-type electrochemical immunosensor was developed for the detection of avian leukosis virus subgroup J (ALV-J), which benefitted from multiple signal amplification involving graphene-perylene-3,4,9,10-tetracarboxylic acid nanocomposites (GR-PTCA), nanocellulose-Au NP composites (NC-Au) and the alkaline phosphatase (ALP) catalytic reaction. GR-PTCA nanocomposites on glassy carbon electrodes served as the immunosensor platform. Due to their excellent electrical conductivity and abundant polycarboxylic sites, the GR-PTCA nanocomposites allowed fast electron transfer and good immobilization of primary antibodies, thereby affording a strong immunosensor signal in the presence of ALV-J. The detected signal could be further amplified by the introduction of NC-Au composites as a carrier of secondary antibodies (Ab 2 ) and by harnessing the catalytic properties of Au and ALP. Under optimized testing conditions, the electrochemical immunosensor displayed excellent analytical performance for the detection of ALV-J, showing a linear current response from 10 2.08 to 10 4.0 TCID 50 /mL (TCID 50 : 50% tissue culture infective dose) with a low detection limit of 10 1.98 TCID 50 /mL (S/N = 3). In addition to high sensitivity, the immunosensor showed very good selectivity, reproducibility and operational stability, demonstrating potential application for the quantitative detection of ALV-J in clinical diagnosis. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Solid-state voltammetry-based electrochemical immunosensor for Escherichia coli using graphene oxide-Ag nanoparticle composites as labels.

    Science.gov (United States)

    Jiang, Xiaochun; Chen, Kun; Wang, Jing; Shao, Kang; Fu, Tao; Shao, Feng; Lu, Donglian; Liang, Jiangong; Foda, M Frahat; Han, Heyou

    2013-06-21

    A new electrochemical immunosensor based on solid-state voltammetry was fabricated for the detection of Escherichia coli (E. coli) by using graphene oxide-Ag nanoparticle composites (P-GO-Ag) as labels. To construct the platform, Au nanoparticles (AuNPs) were first self-assembled on an Au electrode surface through cysteamine and served as an effective matrix for antibody (Ab) attachment. Under a sandwich-type immunoassay format, the analyte and the probe (P-GO-Ag-Ab) were successively captured onto the immunosensor. Finally, the bonded AgNPs were detected through a solid-state redox process in 0.2 M of KCl solution. Combining the advantages of the high-loading capability of graphene oxide with promoted electron-transfer rate of AuNPs, this immunosensor produced a 26.92-fold signal enhancement compared with the unamplified protocol. Under the optimal conditions, the immunosensor exhibited a wide linear dependence on the logarithm of the concentration of E. coli ranging from 50 to 1.0 × 10(6) cfu mL(-1) with a detection limit of 10 cfu mL(-1). Moreover, as a practical application, the proposed immunosensor was used to monitor E. coli in lake water with satisfactory results.

  2. Amperometric Immunosensor for Carbofuran Detection Based on MWCNTs/GS-PEI-Au and AuNPs-Antibody Conjugate

    Directory of Open Access Journals (Sweden)

    Xiangyou Wang

    2013-04-01

    Full Text Available In this paper, an amperometric immunosensor for the detection of carbofuran was developed. Firstly, multiwall carbon nanotubes (MWCNTs and graphene sheets-ethyleneimine polymer-Au (GS-PEI-Au nanocomposites were modified onto the surface of a glass carbon electrode (GCE via self-assembly. The nanocomposites can increase the surface area of the GCE to capture a large amount of antibody, as well as produce a synergistic effect in the electrochemical performance. Then the modified electrode was coated with gold nanoparticles-antibody conjugate (AuNPs-Ab and blocked with BSA. The monoclonal antibody against carbofuran was covalently immobilized on the AuNPs with glutathione as a spacer arm. The morphologies of the GS-PEI-Au nanocomposites and the fabrication process of the immunosensor were characterized by X-ray diffraction (XRD, ultraviolet and visible absorption spectroscopy (UV-vis and scanning electron microscopy (SEM, respectively. Under optimal conditions, the immunosensor showed a wide linear range, from 0.5 to 500 ng/mL, with a detection limit of 0.03 ng/mL (S/N = 3. The as-constructed immunosensor exhibited notable performance features such as high specificity, good reproducibility, acceptable stability and regeneration performance. The results are mainly due to the excellent properties of MWCNTs, GS-PEI-Au nanocomposites and the covalent immobilization of Ab with free hapten binding sites for further immunoreaction. It provides a new avenue for amperometric immunosensor fabrication.

  3. A graphene-based label-free voltammetric immunosensor for sensitive detection of the egg allergen ovalbumin.

    Science.gov (United States)

    Eissa, Shimaa; L'Hocine, Lamia; Siaj, Mohamed; Zourob, Mohammed

    2013-08-07

    A graphene-based label-free voltammetric immunosensor for the sensitive detection of the egg white allergen ovalbumin has been developed. Graphene-modified screen printed carbon electrodes have been covalently functionalized using electrochemical reduction of in situ generated aryl diazonium salt forming a carboxyphenyl film on the graphene surface. The blocking property of the carboxyphenyl film grafted on to the graphene electrodes using different cyclic voltammetry cycles has been characterized using differential pulse voltammetry in [Fe(CN)6](3-/4-) solution. Then, the terminal carboxylic groups on the graphene surface were activated using EDC/NHS and used to immobilize the ovalbumin antibody and construct the immunosensor. The fabrication steps of the immunosensor have also been characterized using differential pulse voltammetry. The decrease in the [Fe(CN)6](3-/4-) reduction peak current after the immunochemical reaction with ovalbumin has been used for the ovalbumin detection. The developed immunosensor has been used for ovalbumin detection in the concentration range of 1 pg mL(-1) to 0.5 μg mL(-1) with a detection limit of 0.83 pg mL(-1) in PBS buffer. The food matrix effect studied with ovalbumin spiked cake extract showed a good percentage of recovery, indicating the possible applicability of the developed immunosensor in real food samples.

  4. Rossing uranium

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    In this article the geology of the deposits of the Rossing uranium mine in Namibia is discussed. The planning of the open-pit mining, the blasting, drilling, handling and the equipment used for these processes are described

  5. Uranium, depleted uranium, biological effects

    International Nuclear Information System (INIS)

    2001-01-01

    Physicists, chemists and biologists at the CEA are developing scientific programs on the properties and uses of ionizing radiation. Since the CEA was created in 1945, a great deal of research has been carried out on the properties of natural, enriched and depleted uranium in cooperation with university laboratories and CNRS. There is a great deal of available data about uranium; thousands of analyses have been published in international reviews over more than 40 years. This presentation on uranium is a very brief summary of all these studies. (author)

  6. Uranium loans

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    When NUEXCO was organized in 1968, its founders conceived of a business based on uranium loans. The concept was relatively straightforward; those who found themselves with excess supplies of uranium would deposit those excesses in NUEXCO's open-quotes bank,close quotes and those who found themselves temporarily short of uranium could borrow from the bank. The borrower would pay interest based on the quantity of uranium borrowed and the duration of the loan, and the bank would collect the interest, deduct its service fee for arranging the loan, and pay the balance to those whose deposits were borrowed. In fact, the original plan was to call the firm Nuclear Bank Corporation, until it was discovered that using the word open-quotes Bankclose quotes in the name would subject the firm to various US banking regulations. Thus, Nuclear Bank Corporation became Nuclear Exchange Corporation, which was later shortened to NUEXCO. Neither the nuclear fuel market nor NUEXCO's business developed quite as its founders had anticipated. From almost the very beginning, the brokerage of uranium purchases and sales became a more significant activity for NUEXCO than arranging uranium loans. Nevertheless, loan transactions have played an important role in the international nuclear fuel market, requiring the development of special knowledge and commercial techniques

  7. Uranium extraction from gold-uranium ores

    Energy Technology Data Exchange (ETDEWEB)

    Laskorin, B.N.; Golynko, Z.Sh.

    1981-01-01

    The process of uranium extraction from gold-uranium ores in the South Africa is considered. Flowsheets of reprocessing gold-uranium conglomerates, pile processing and uranium extraction from the ores are presented. Continuous counter flow ion-exchange process of uranium extraction using strong-active or weak-active resins is noted to be the most perspective and economical one. The ion-exchange uranium separation with the succeeding extraction is also the perspective one.

  8. Optical waveguide lightmode spectroscopy technique-based immunosensor development for aflatoxin B1 determination in spice paprika samples.

    Science.gov (United States)

    Majer-Baranyi, Krisztina; Zalán, Zsolt; Mörtl, Mária; Juracsek, Judit; Szendrő, István; Székács, András; Adányi, Nóra

    2016-11-15

    Optical waveguide lightmode spectroscopy (OWLS) technique has been applied to label-free detection of aflatoxin B1 in a competitive immunoassay format, with the aim to compare the analytical goodness of the developed OWLS immunosenor with HPLC and enzyme-linked immunosorbent assay (ELISA) methods for the detection of aflatoxin in spice paprika matrix. We have also assessed applicability of the QuEChERS method prior to ELISA measurements, and the results were compared to those obtained by traditional solvent extraction followed by immunoaffinity clean-up. The AFB1 content of sixty commercial spice paprika samples from different countries were measured with the developed and optimized OWLS immunosensor. Comparing the results from the indirect immunosensor to that obtained by HPLC or ELISA provided excellent correlation (with regression coefficients above 0.94) indicating that the competitive OWLS immunosensor has a potential for quick determination of aflatoxin B1 in paprika samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Uranium mining

    International Nuclear Information System (INIS)

    2008-01-01

    Full text: The economic and environmental sustainability of uranium mining has been analysed by Monash University researcher Dr Gavin Mudd in a paper that challenges the perception that uranium mining is an 'infinite quality source' that provides solutions to the world's demand for energy. Dr Mudd says information on the uranium industry touted by politicians and mining companies is not necessarily inaccurate, but it does not tell the whole story, being often just an average snapshot of the costs of uranium mining today without reflecting the escalating costs associated with the process in years to come. 'From a sustainability perspective, it is critical to evaluate accurately the true lifecycle costs of all forms of electricity production, especially with respect to greenhouse emissions, ' he says. 'For nuclear power, a significant proportion of greenhouse emissions are derived from the fuel supply, including uranium mining, milling, enrichment and fuel manufacture.' Dr Mudd found that financial and environmental costs escalate dramatically as the uranium ore is used. The deeper the mining process required to extract the ore, the higher the cost for mining companies, the greater the impact on the environment and the more resources needed to obtain the product. I t is clear that there is a strong sensitivity of energy and water consumption and greenhouse emissions to ore grade, and that ore grades are likely to continue to decline gradually in the medium to long term. These issues are critical to the current debate over nuclear power and greenhouse emissions, especially with respect to ascribing sustainability to such activities as uranium mining and milling. For example, mining at Roxby Downs is responsible for the emission of over one million tonnes of greenhouse gases per year and this could increase to four million tonnes if the mine is expanded.'

  10. Double electrochemical covalent coupling method based on click chemistry and diazonium chemistry for the fabrication of sensitive amperometric immunosensor.

    Science.gov (United States)

    Qi, Honglan; Li, Min; Zhang, Rui; Dong, Manman; Ling, Chen

    2013-08-20

    A double electrochemical covalent coupling method based on click chemistry and diazonium chemistry for the fabrication of sensitive amperometric immunosensor was developed. As a proof-of-concept, a designed alkyne functionalized human IgG was used as a capture antibody and a HRP-labeled rabbit anti-goat IgG was used as signal antibody for the determination of the anti-human IgG using the sandwich model. The immunosensor was fabricated by electrochemically grafting a phenylazide on the surface of a glassy carbon electrode, and then, by coupling the alkyne functionalized human IgG with the phenylazide group through an electro-click chemistry in the presence of Cu(II). The amperometric measurement for the determination of the anti-human IgG was performed after the fabricated immunosensor was incubated with the target anti-human IgG and then with the HRP-labeled anti-goat IgG at -0.25V in 0.10M PBS (pH 7.0) containing 0.1mM hydroquinone and 2.0mM H2O2. The results showed that the increased current was linear with the logarithm of the concentration of the anti-human IgG in the range from 1.0×10(-10)g mL(-1) to 1.0×10(-8)g mL(-1) with a detection limit of 3×10(-11)g mL(-1). Furthermore, the feasibility of the double electrochemical covalent coupling method proposed in this work for fabricating the amperometric immunosensor array was explored. This work demonstrates that the double electrochemical covalent coupling method is a promising approach for the fabrication of the immunosensor and immunosensor array. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. The latest figures on uranium

    International Nuclear Information System (INIS)

    Vance, R.

    2010-01-01

    According to the latest figures on uranium, soon to be published by the NEA, uranium resources, production and demand are all on the rise. Exploration efforts have increased recently in line with the expected expansion of nuclear energy in the coming years. Total identified resources have grown and are now sufficient to cover 100 years of supply at 2008 rates of consumption. Costs of production have, however, also increased. This article is based on the latest edition of the 'Red Book', Uranium 2009: Resources, Production and Demand, which presents the results of the most recent biennial review of world uranium market fundamentals and a statistical profile of the world uranium industry as of 1 January 2009. It contains official data provided by OECD Nuclear Energy Agency (NEA) and International Atomic Energy Agency (IAEA) member countries on uranium exploration, resources, production and reactor-related requirements. Projections of nuclear generating capacity and reactor-related uranium requirements through 2035 are also provided as well as a discussion of long-term uranium supply and demand issues. Despite recent declines stemming from the global financial crisis, world demand for electricity is expected to continue to grow significantly over the next several decades to meet the needs of an increasing population and economic growth. The recognition by an increasing number of governments that nuclear power can produce competitively priced, base-load electricity that is essentially free of greenhouse gas emissions, coupled with the role that nuclear can play in enhancing security of energy supply, increases the prospects for growth in nuclear generating capacity, although the magnitude of that growth remains to be determined. Regardless of the role that nuclear energy ultimately plays in meeting rising electricity demand, the uranium resource base is more than adequate to meet projected requirements. Meeting even high-case requirements to 2035 would consume less

  12. Uranium enrichment

    International Nuclear Information System (INIS)

    Rae, H.K.; Melvin, J.G.

    1988-06-01

    Canada is the world's largest producer and exporter of uranium, most of which is enriched elsewhere for use as fuel in LWRs. The feasibility of a Canadian uranium-enrichment enterprise is therefore a perennial question. Recent developments in uranium-enrichment technology, and their likely impacts on separative work supply and demand, suggest an opportunity window for Canadian entry into this international market. The Canadian opportunity results from three particular impacts of the new technologies: 1) the bulk of the world's uranium-enrichment capacity is in gaseous diffusion plants which, because of their large requirements for electricity (more than 2000 kW·h per SWU), are vulnerable to competition from the new processes; 2) the decline in enrichment costs increases the economic incentive for the use of slightly-enriched uranium (SEU) fuel in CANDU reactors, thus creating a potential Canadian market; and 3) the new processes allow economic operation on a much smaller scale, which drastically reduces the investment required for market entry and is comparable with the potential Canadian SEU requirement. The opportunity is not open-ended. By the end of the century the enrichment supply industry will have adapted to the new processes and long-term customer/supplier relationships will have been established. In order to seize the opportunity, Canada must become a credible supplier during this century

  13. Uranium update

    International Nuclear Information System (INIS)

    Steane, R.

    1997-01-01

    This paper is about the current uranium mining situation, especially that in Saskatchewan. Canada has a unique advantage with the Saskatchewan uranium deposits. Making the most of this opportunity is important to Canada. The following is reviewed: project development and the time and capital it takes to bring a new project into production; the supply and demand situation to show where the future production fits into the world market; and our foreign competition and how we have to be careful not to lose our opportunity. (author)

  14. Nanostructured progesterone immunosensor using a tyrosinase-colloidal gold-graphite-Teflon biosensor as amperometric transducer

    Energy Technology Data Exchange (ETDEWEB)

    Carralero, Veronica [Department of Analytical Chemistry, Faculty of Chemistry, University Complutense of Madrid, 28040 Madrid (Spain); Gonzalez-Cortes, Araceli [Department of Analytical Chemistry, Faculty of Chemistry, University Complutense of Madrid, 28040 Madrid (Spain); Yanez-Sedeno, Paloma [Department of Analytical Chemistry, Faculty of Chemistry, University Complutense of Madrid, 28040 Madrid (Spain)]. E-mail: yseo@quim.ucm.es; Pingarron, Jose M. [Department of Analytical Chemistry, Faculty of Chemistry, University Complutense of Madrid, 28040 Madrid (Spain)

    2007-07-16

    A novel progesterone immunosensor using a colloidal gold-graphite-Teflon-tyrosinase composite biosensor as amperometric transducer is reported. A sequential competitive configuration between the analyte and progesterone labelled with alkaline phosphatase (AP) was used. Phenyl phosphate was employed as the AP-substrate and the enzyme reaction product, phenol, was oxidized by tyrosinase to o-quinone, which is subsequently reduced at -0.1 V at the biocomposite electrode. Variables such as the concentration of phenyl phosphate, the amount of antibody attached to the electrode surface, immersion time in a 2% BSA solution, working pH and incubation times in progesterone and AP conjugate were optimized. A linear calibration graph for progesterone was obtained between 0 and 40 ng mL{sup -1} with a slope value of -82.3 nA ng{sup -1} mL, and a detection limit of 0.43 ng mL{sup -1}. The time needed to reach the steady-state current from the addition of phenyl phosphate was 30-40 s. These analytical characteristics improve substantially those reported for other progesterone immunosensors. A lifetime of 14 days with no need to apply any regeneration procedure was also achieved. The usefulness of the immunosensor was evaluated by determining progesterone in milk samples spiked with the analyte at 5.0 and 1.5 ng mL{sup -1} concentration levels. Following a very simple procedure, involving only sample dilution, mean recoveries (n = 7) of 98 {+-} 3% and 99 {+-} 3%, respectively, were obtained.

  15. Nanostructured progesterone immunosensor using a tyrosinase-colloidal gold-graphite-Teflon biosensor as amperometric transducer

    International Nuclear Information System (INIS)

    Carralero, Veronica; Gonzalez-Cortes, Araceli; Yanez-Sedeno, Paloma; Pingarron, Jose M.

    2007-01-01

    A novel progesterone immunosensor using a colloidal gold-graphite-Teflon-tyrosinase composite biosensor as amperometric transducer is reported. A sequential competitive configuration between the analyte and progesterone labelled with alkaline phosphatase (AP) was used. Phenyl phosphate was employed as the AP-substrate and the enzyme reaction product, phenol, was oxidized by tyrosinase to o-quinone, which is subsequently reduced at -0.1 V at the biocomposite electrode. Variables such as the concentration of phenyl phosphate, the amount of antibody attached to the electrode surface, immersion time in a 2% BSA solution, working pH and incubation times in progesterone and AP conjugate were optimized. A linear calibration graph for progesterone was obtained between 0 and 40 ng mL -1 with a slope value of -82.3 nA ng -1 mL, and a detection limit of 0.43 ng mL -1 . The time needed to reach the steady-state current from the addition of phenyl phosphate was 30-40 s. These analytical characteristics improve substantially those reported for other progesterone immunosensors. A lifetime of 14 days with no need to apply any regeneration procedure was also achieved. The usefulness of the immunosensor was evaluated by determining progesterone in milk samples spiked with the analyte at 5.0 and 1.5 ng mL -1 concentration levels. Following a very simple procedure, involving only sample dilution, mean recoveries (n = 7) of 98 ± 3% and 99 ± 3%, respectively, were obtained

  16. Label free sensing of creatinine using a 6 GHz CMOS near-field dielectric immunosensor.

    Science.gov (United States)

    Guha, S; Warsinke, A; Tientcheu, Ch M; Schmalz, K; Meliani, C; Wenger, Ch

    2015-05-07

    In this work we present a CMOS high frequency direct immunosensor operating at 6 GHz (C-band) for label free determination of creatinine. The sensor is fabricated in standard 0.13 μm SiGe:C BiCMOS process. The report also demonstrates the ability to immobilize creatinine molecules on a Si3N4 passivation layer of the standard BiCMOS/CMOS process, therefore, evading any further need of cumbersome post processing of the fabricated sensor chip. The sensor is based on capacitive detection of the amount of non-creatinine bound antibodies binding to an immobilized creatinine layer on the passivated sensor. The chip bound antibody amount in turn corresponds indirectly to the creatinine concentration used in the incubation phase. The determination of creatinine in the concentration range of 0.88-880 μM is successfully demonstrated in this work. A sensitivity of 35 MHz/10 fold increase in creatinine concentration (during incubation) at the centre frequency of 6 GHz is gained by the immunosensor. The results are compared with a standard optical measurement technique and the dynamic range and sensitivity is of the order of the established optical indication technique. The C-band immunosensor chip comprising an area of 0.3 mm(2) reduces the sensing area considerably, therefore, requiring a sample volume as low as 2 μl. The small analyte sample volume and label free approach also reduce the experimental costs in addition to the low fabrication costs offered by the batch fabrication technique of CMOS/BiCMOS process.

  17. Carbon nanotubes-based chemiresistive immunosensor for small molecules: detection of nitroaromatic explosives.

    Science.gov (United States)

    Park, Miso; Cella, Lakshmi N; Chen, Wilfred; Myung, Nosang V; Mulchandani, Ashok

    2010-12-15

    In recent years, there has been a growing focus on use of one-dimensional (1-D) nanostructures, such as carbon nanotubes and nanowires, as transducer elements for label-free chemiresistive/field-effect transistor biosensors as they provide label-free and high sensitivity detection. While research to-date has elucidated the power of carbon nanotubes- and other 1-D nanostructure-based field effect transistors immunosensors for large charged macromolecules such as proteins and viruses, their application to small uncharged or charged molecules has not been demonstrated. In this paper we report a single-walled carbon nanotubes (SWNTs)-based chemiresistive immunosensor for label-free, rapid, sensitive and selective detection of 2,4,6-trinitrotoluene (TNT), a small molecule. The newly developed immunosensor employed a displacement mode/format in which SWNTs network forming conduction channel of the sensor was first modified with trinitrophenyl (TNP), an analog of TNT, and then ligated with the anti-TNP single chain antibody. Upon exposure to TNT or its derivatives the bound antibodies were displaced producing a large change, several folds higher than the noise, in the resistance/conductance of SWNTs giving excellent limit of detection, sensitivity and selectivity. The sensor detected between 0.5 ppb and 5000 ppb TNT with good selectivity to other nitroaromatic explosives and demonstrated good accuracy for monitoring TNT in untreated environmental water matrix. We believe this new displacement format can be easily generalized to other one-dimensional nanostructure-based chemiresistive immuno/affinity-sensors for detecting small and/or uncharged molecules of interest in environmental monitoring and health care. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. Machining of uranium and uranium alloys

    International Nuclear Information System (INIS)

    Morris, T.O.

    1981-01-01

    Uranium and uranium alloys can be readily machined by conventional methods in the standard machine shop when proper safety and operating techniques are used. Material properties that affect machining processes and recommended machining parameters are discussed. Safety procedures and precautions necessary in machining uranium and uranium alloys are also covered. 30 figures

  19. Impedimetric immunosensor for human serum albumin detection on a direct aldehyde-functionalized silicon nitride surface

    Energy Technology Data Exchange (ETDEWEB)

    Caballero, David, E-mail: caballero@unistra.fr [Nanobioengineering group-IBEC, Barcelona Science Park, C/ Baldiri Reixach 10-12, 08028 Barcelona (Spain); University of Barcelona, Department of Electronics, C/ Marti i Franques 1, 08028 Barcelona (Spain); Centro de Investigacion Biomedica en Red en Bioingenieria, Biomateriales y Nanomedicina (CIBER-BBN), 50018 Zaragoza (Spain); Martinez, Elena [Nanobioengineering group-IBEC, Barcelona Science Park, C/ Baldiri Reixach 10-12, 08028 Barcelona (Spain); Centro de Investigacion Biomedica en Red en Bioingenieria, Biomateriales y Nanomedicina (CIBER-BBN), 50018 Zaragoza (Spain); Bausells, Joan [Centre Nacional de Microelectronica (CNM-IMB), CSIC, Campus UAB, 08193 Bellaterra (Spain); Errachid, Abdelhamid, E-mail: abdelhamid.errachid-el-salhi@univ-lyon1.fr [Nanobioengineering group-IBEC, Barcelona Science Park, C/ Baldiri Reixach 10-12, 08028 Barcelona (Spain); Universite Claude Bernard - Lyon 1, LSA - UMR 5180, 43 Bd du 11 novembre 1918, 69622 Villeurbanne Cedex (France); Samitier, Josep [Nanobioengineering group-IBEC, Barcelona Science Park, C/ Baldiri Reixach 10-12, 08028 Barcelona (Spain); University of Barcelona, Department of Electronics, C/ Marti i Franques 1, 08028 Barcelona (Spain); Centro de Investigacion Biomedica en Red en Bioingenieria, Biomateriales y Nanomedicina (CIBER-BBN), 50018 Zaragoza (Spain)

    2012-03-30

    Highlights: Black-Right-Pointing-Pointer An impedimetric label-free immunosensor was developed for the specific detection of human serum albumin proteins. Black-Right-Pointing-Pointer Anti-HSA antibodies were covalently immobilized on silicon nitride surfaces using a direct functionalization methodology. Black-Right-Pointing-Pointer Silicon nitride offers multiple advantages compared to other common materials. Black-Right-Pointing-Pointer The proposed sensor has high sensitivity and good selectivity for the detection of HSA proteins. - Abstract: In this work we report the fabrication and characterization of a label-free impedimetric immunosensor based on a silicon nitride (Si{sub 3}N{sub 4}) surface for the specific detection of human serum albumin (HSA) proteins. Silicon nitride provides several advantages compared with other materials commonly used, such as gold, and in particular in solid-state physics for electronic-based biosensors. However, few Si{sub 3}N{sub 4}-based biosensors have been developed; the lack of an efficient and direct protocol for the integration of biological elements with silicon-based substrates is still one of its the main drawbacks. Here, we use a direct functionalization method for the direct covalent binding of monoclonal anti-HSA antibodies on an aldehyde-functionalized Si-p/SiO{sub 2}/Si{sub 3}N{sub 4} structure. This methodology, in contrast with most of the protocols reported in literature, requires less chemical reagents, it is less time-consuming and it does not need any chemical activation. The detection capability of the immunosensor was tested by performing non-faradaic electrochemical impedance spectroscopy (EIS) measurements for the specific detection of HSA proteins. Protein concentrations within the linear range of 10{sup -13}-10{sup -7} M were detected, showing a sensitivity of 0.128 {Omega} {mu}M{sup -1} and a limit of detection of 10{sup -14} M. The specificity of the sensor was also addressed by studying the

  20. Impedimetric immunosensor for human serum albumin detection on a direct aldehyde-functionalized silicon nitride surface

    International Nuclear Information System (INIS)

    Caballero, David; Martinez, Elena; Bausells, Joan; Errachid, Abdelhamid; Samitier, Josep

    2012-01-01

    Highlights: ► An impedimetric label-free immunosensor was developed for the specific detection of human serum albumin proteins. ► Anti-HSA antibodies were covalently immobilized on silicon nitride surfaces using a direct functionalization methodology. ► Silicon nitride offers multiple advantages compared to other common materials. ► The proposed sensor has high sensitivity and good selectivity for the detection of HSA proteins. - Abstract: In this work we report the fabrication and characterization of a label-free impedimetric immunosensor based on a silicon nitride (Si 3 N 4 ) surface for the specific detection of human serum albumin (HSA) proteins. Silicon nitride provides several advantages compared with other materials commonly used, such as gold, and in particular in solid-state physics for electronic-based biosensors. However, few Si 3 N 4 -based biosensors have been developed; the lack of an efficient and direct protocol for the integration of biological elements with silicon-based substrates is still one of its the main drawbacks. Here, we use a direct functionalization method for the direct covalent binding of monoclonal anti-HSA antibodies on an aldehyde-functionalized Si-p/SiO 2 /Si 3 N 4 structure. This methodology, in contrast with most of the protocols reported in literature, requires less chemical reagents, it is less time-consuming and it does not need any chemical activation. The detection capability of the immunosensor was tested by performing non-faradaic electrochemical impedance spectroscopy (EIS) measurements for the specific detection of HSA proteins. Protein concentrations within the linear range of 10 −13 –10 −7 M were detected, showing a sensitivity of 0.128 Ω μM −1 and a limit of detection of 10 −14 M. The specificity of the sensor was also addressed by studying the interferences with a similar protein, bovine serum albumin. The results obtained show that the antibodies were efficiently immobilized and the proteins

  1. Uranium mining

    International Nuclear Information System (INIS)

    Cheeseman, E.W.

    1980-01-01

    The international uranium market appears to be currently over-supplied with a resultant softening in prices. Buyers on the international market are unhappy about some of the restrictions placed on sales by the government, and Canadian sales may suffer as a result. About 64 percent of Canada's shipments come from five operating Ontario mines, with the balance from Saskatchewan. Several other properties will be producing within the next few years. In spite of the adverse effects of the Three Mile Island incident and the default by the T.V.A. of their contract, some 3 600 tonnes of new uranium sales were completed during the year. The price for uranium had stabilized at US $42 - $44 by mid 1979, but by early 1980 had softened somewhat. The year 1979 saw the completion of major environmental hearings in Ontario and Newfoundland and the start of the B.C. inquiry. Two more hearings are scheduled for Saskatchewan in 1980. The Elliot Lake uranium mining expansion hearings are reviewed, as are other recent hearings. In the production of uranium for nuclear fuel cycle, environmental matters are of major concern to the industry, the public and to governments. Research is being conducted to determine the most effective method for removing radium from tailings area effluents. Very stringent criteria are being drawn up by the regulatory agencies that must be met by the industry in order to obtain an operating licence from the AECB. These criteria cover seepages from the tailings basin and through the tailings retention dam, seismic stability, and both short and long term management of the tailings waste management area. (auth)

  2. Uranium industry annual 1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-04-01

    The Uranium Industry Annual 1996 (UIA 1996) provides current statistical data on the US uranium industry`s activities relating to uranium raw materials and uranium marketing. The UIA 1996 is prepared for use by the Congress, Federal and State agencies, the uranium and nuclear electric utility industries, and the public. Data on uranium raw materials activities for 1987 through 1996 including exploration activities and expenditures, EIA-estimated reserves, mine production of uranium, production of uranium concentrate, and industry employment are presented in Chapter 1. Data on uranium marketing activities for 1994 through 2006, including purchases of uranium and enrichment services, enrichment feed deliveries, uranium fuel assemblies, filled and unfilled market requirements, uranium imports and exports, and uranium inventories are shown in Chapter 2. A feature article, The Role of Thorium in Nuclear Energy, is included. 24 figs., 56 tabs.

  3. Uranium industry annual 1996

    International Nuclear Information System (INIS)

    1997-04-01

    The Uranium Industry Annual 1996 (UIA 1996) provides current statistical data on the US uranium industry's activities relating to uranium raw materials and uranium marketing. The UIA 1996 is prepared for use by the Congress, Federal and State agencies, the uranium and nuclear electric utility industries, and the public. Data on uranium raw materials activities for 1987 through 1996 including exploration activities and expenditures, EIA-estimated reserves, mine production of uranium, production of uranium concentrate, and industry employment are presented in Chapter 1. Data on uranium marketing activities for 1994 through 2006, including purchases of uranium and enrichment services, enrichment feed deliveries, uranium fuel assemblies, filled and unfilled market requirements, uranium imports and exports, and uranium inventories are shown in Chapter 2. A feature article, The Role of Thorium in Nuclear Energy, is included. 24 figs., 56 tabs

  4. Uranium industry annual, 1991

    International Nuclear Information System (INIS)

    1992-10-01

    In the Uranium Industry Annual 1991, data on uranium raw materials activities including exploration activities and expenditures, resources and reserves, mine production of uranium, production of uranium concentrate, and industry employment are presented in Chapter 1. Data on uranium marketing activities including domestic uranium purchases, commitments by utilities, procurement arrangements, uranium imports under purchase contracts and exports, deliveries to enrichment suppliers, inventories, secondary market activities, utility market requirements, and uranium for sale by domestic suppliers are presented in Chapter 2. A feature article entitled ''The Uranium Industry of the Commonwealth of Independent States'' is included in this report

  5. A novel electrochemiluminescent immunosensor based on the quenching effect of aminated graphene on nitrogen-doped carbon quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jing; Han, Tongqian; Ma, Hongmin; Yan, Tao; Pang, Xuehui [Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022 (China); Li, Yueyun [School of Chemical Engineering, Shandong University of Technology, Zibo 255049 (China); Wei, Qin, E-mail: sdjndxwq@163.com [Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022 (China)

    2015-08-19

    Nitrogen-doped carbon quantum dots (N-CQDs) with an average diameter of 2 nm were synthesized by carbonization of diethylene triamine pentacetate acid (DTPA). The simple prepared N-CQDs showed excellent electrochemiluminescence (ECL) property and were used as luminophors to fabricate a sandwich-type ECL immunosensor. Aminated graphene (NH{sub 2}-G) was also synthesized and used as a label of secondary antibody. The labeled NH{sub 2}-G could effectively quench the ECL of N-CQDs modified on electrodes due to ECL resonance energy transfer (ERET). Immunological recognition which induced ECL quenching enabled the quantitative determination of biomarkers. Alpha fetoprotein (AFP) was selected as a model analyte to investigate the analytical performance of the proposed immunosensor. Under optimal conditions, a good linear relationship between ECL intensity and the logarithm of AFP concentration was obtained in the range of 0.01–100 ng mL{sup −1} with the detection limit of 3.3 pg mL{sup −1}. The proposed ECL immunosensor showed good stability, acceptable selectivity and reproducibility. - Highlights: • ECL behavior of N-CQDs was investigated. • NH{sub 2}-G for quenching N-CQDs emission was investigated. • The linearly range of the immunosensor for AFP was 0.01 ng/mL–100 ng/mL.

  6. A label-free electrochemical immunosensor for the detection of cardiac marker using graphene quantum dots (GQDs).

    Science.gov (United States)

    Tuteja, Satish K; Chen, Rui; Kukkar, Manil; Song, Chung Kil; Mutreja, Ruchi; Singh, Suman; Paul, Ashok K; Lee, Haiwon; Kim, Ki-Hyun; Deep, Akash; Suri, C Raman

    2016-12-15

    A label-free immunosensor based on electrochemical impedance spectroscopy has been developed for the sensitive detection of a cardiac biomarker myoglobin (cMyo). Hydrothermally synthesized graphene quantum dots (GQDs) have been used as an immobilized template on screen printed electrodes for the construction of an impedimetric sensor platform. The GQDs-modified electrode was conjugated with highly specific anti-myoglobin antibodies to develop the desired immunosensor. The values of charge transfer resistance (Rct) were monitored as a function of varying antigen concentration. The Rct value of the immunosensor showed a linear increase (from 0.20 to 0.31kΩ) in the range of 0.01-100ng/mL cMyo. The specific detection of cMyo was also made in the presence of other competing proteins. The limit of detection for the proposed immunosensor was estimated as 0.01ng/mL which is comparable to the standard ELISA techniques. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. A disposable electrochemical immunosensor based on carbon screen-printed electrodes for the detection of prostate specific antigen.

    Science.gov (United States)

    Yan, Mei; Zang, Dejin; Ge, Shenguang; Ge, Lei; Yu, Jinghua

    2012-01-01

    A novel screen-printed electrode (SPEs) on sheets of vegetable parchment was prepared. The obtained SPEs were stable, convenient, inexpensive and suitable for large-area screen-printing. With these SPEs, we explored the fabrication of a novel, disposable and highly sensitive electro-analytical immunosensor using graphene nanosheets (GS) and horseradish peroxidase (HRP)-labeled signal antibody functionalized with gold nanoparticles (HRP-Ab(2)/Au NPs). GS was used to increase the conductivity and stability of this immunosensor due to its fast electron transportation and good biocompatibility. Au NPs could not only provide a large surface area for the immobilization of HRP-Ab(2) but also enhance the electroreduction between HRP and H(2)O(2) to amplify the electrochemical signal on the sandwich immuno-complexes modified SPEs. The proposed SPEs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical methods involving cyclic voltammetry (CV), and electrochemical impedence method. Using prostate specific antigen (PSA) as a model analyte, this immunosensor showed a wide linear range over 6 orders of magnitude with the minimum value down to 2 pg mL(-1). In addition, this immunosensor could avoid the need of deoxygenation for the electrochemical immunoassay. Thus, it provided a promising potential in clinical applications. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Amperometric immunosensor based on multiwalled carbon nanotubes/Prussian blue/nanogold-modified electrode for determination of α-fetoprotein.

    Science.gov (United States)

    Jiang, Wen; Yuan, Ruo; Chai, Ya-Qin; Yin, Bing

    2010-12-01

    In this article, a conspicuously simple and highly sensitive amperometric immunosensor based on the sequential electrodeposition of Prussian blue (PB) and gold nanoparticles (GNPs) on multiwalled carbon nanotube (MWCNT)-modified glassy carbon electrode (GCE) surface is proposed for the detection of α-fetoprotein (AFP). By comparison with PB, the MWCNT/PB composite film had been proven to show much better electrochemical stability and a larger response current. The electrodeposited GNP film can be used not only to immobilize biomolecules but also to avoid the leakage of PB and to prevent shedding of MWCNT/PB composite film from the electrode surface. The performance and factors influencing the performance of the immunosensor were investigated. Under optimal experimental conditions, the proposed immunosensor for AFP was observed with an ultralow limit of detection (LOD) equal to 3 pg/ml (at 3δ), and the linear working range spanned the concentrations of AFP from 0.01 to 300 ng/ml. Moreover, the immunosensor, as well as a commercially available kit, was examined for use in the determination of AFP in real human serum specimens. More significant, the assay mentioned here is simpler than the traditional enzyme-linked immunosorbent assay (ELISA), and an excellent correlation of levels of AFP measured was obtained, indicating that the developed immunoassay could be a promising alternative approach for detection of AFP and other tumor markers in the clinical diagnosis. Copyright © 2010 Elsevier Inc. All rights reserved.

  9. Application of a Label-Free Immunosensor for White Spot Syndrome Virus (WSSV) in Shrimp Cultivation Water.

    Science.gov (United States)

    Waiyapoka, Thanyaporn; Deachamag, Panchalika; Chotigeat, Wilaiwan; Bunsanong, Nittaya; Kanatharana, Proespichaya; Thavarungkul, Panote; Loyprasert-Thananimit, Suchera

    2015-10-01

    White spot syndrome virus (WSSV) is a major pathogen affecting the shrimp industry worldwide. In a preliminary study, WSSV binding protein (WBP) was specifically bound to the VP26 protein of WSSV. Therefore, we have developed the label-free affinity immunosensor using the WBP together with anti-GST-VP26 for quantitative detection of WSSV in shrimp pond water. When the biological molecules were immobilized on a gold electrode to form a self-assembled monolayer, it was then used to detect WSSV using a flow injection system with optimized conditions. Binding between the different copies of WSSV and the immobilized biological molecules was detected by an impedance change (ΔZ″) in real time. The sensitivity of the developed immunosensor was in the linear range of 1.6 × 10(1)-1.6 × 10(6) copies/μl. The system was highly sensitive for the analysis of WSSV as shown by the lack of impedance change when using yellow head virus (YHV). The developed immunosensor could be reused up to 37 times (relative standard deviation (RSD), 3.24 %) with a good reproducibility of residual activity (80-110 %). The immunosensor was simple to operate, reliable, reproducible, and could be applied for the detection and quantification of WSSV in water during shrimp cultivation.

  10. Development of electrochemical immunosensors based on different serum antibody immobilization methods for detection of Japanese encephalitis virus

    International Nuclear Information System (INIS)

    Tran, Quang Huy; Hanh Nguyen, Thi Hong; Phan, Thi Nga; Mai, Anh Tuan; Nguyen, Thi Thuy; Vu, Quang Khue

    2012-01-01

    This paper describes the development of electrochemical immunosensors based on human serum antibodies with different immobilization methods for detection of Japanese encephalitis virus (JEV). Human serum containing anti-JEV antibodies was used to immobilize onto the surface of silanized interdigitated electrodes by four methods: direct adsorption (APTES-serum), covalent binding with a cross linker of glutaraldehyde (APTES-GA-serum), covalent binding with a cross linker of glutaraldehyde combined with anti-human IgG (APTES-GA-anti-HIgG-serum) and covalent binding with a cross linker of glutaraldehyde combined with a bioaffinity of protein A (APTES-GA-PrA-serum). Atomic force microscopy was used to verify surface characteristics of the interdigitated electrodes before and after treatment with serum antibodies. The output signal of the immunosensors was measured by the change of conductivity resulting from the specific binding of JEV antigens and serum antibodies immobilized on the electrodes, with the help of horseradish peroxidase (HRP)-labeled secondary antibody against JEV. The results showed that the APTES-GA-PrA-serum method provided the highest signal of the electrochemical immunosensor for detection of JEV antigens, with the linear range from 25 ng ml −1 to 1 μg ml −1 , and the limit of detection was about 10 ng ml −1 . This study shows a potential development of novel electrochemical immunosensors applied for virus detection in clinical samples in case of possible outbreaks

  11. Lichens as biomonitors of uranium in the Balkan area

    International Nuclear Information System (INIS)

    Loppi, S.; Riccobono, F.; Zhang, Z.H.; Savic, S.; Ivanov, D.; Pirintsos, S.A.

    2003-01-01

    Widespread contamination by depleted uranium was not detected in the Balkan area. - The contribution of the conflict of 1999 to the environmental levels of uranium in the Balkan area was evaluated by means of lichens used as biomonitors. The average U concentration found in lichens in the present study was in line with the values reported for lichens from other countries and well below the levels found in lichens collected in areas with natural or anthropogenic sources of U. Measurement of isotopic ratios 235 U/ 238 U allowed to exclude the presence of depleted uranium. According to these results, we could not detect widespread environmental contamination by depleted uranium in the Balkan area

  12. Label-Free QCM Immunosensor for the Detection of Ochratoxin A

    Directory of Open Access Journals (Sweden)

    Şerife Şeyda Pirinçci

    2018-04-01

    Full Text Available Ochratoxin A (OTA is a potent mycotoxin that poses a risk in food and feed moieties and subject to worldwide regulation. Laboratory-based analytical methods are traditionally employed for reliable OTA quantification, but these methods cannot provide rapid and on-site analysis, where biosensors fill this gap. In this study a label-free quartz crystal microbalance (QCM-based immunosensor for the detection of OTA, which is one of the most important small molecule contaminants, was developed by direct immobilization of OTA to amine-bearing sensor surfaces using 1-ethyl-3-(3-dimethylaminopropyl carbodiimide (EDC/N-Hydroxysuccinimide (NHS chemistry. The protein-free sensor surface enabled regeneration of sensor surface with 50 mM NaOH and 1% SDS up to 13 times without loss of performance, which would disrupt a protein-containing sensor surface. We developed a QCM immunosensor using the developed sensor surface with a 17.2–200 ng/mL detection range which can be used for on-site detection of feedstuffs.

  13. Electrochemical immunosensor for ethinylestradiol using diazonium salt grafting onto silver nanoparticles-silica-graphene oxide hybrids.

    Science.gov (United States)

    Cincotto, Fernando H; Martínez-García, Gonzalo; Yáñez-Sedeño, Paloma; Canevari, Thiago C; Machado, S A S; Pingarrón, José M

    2016-01-15

    This work describes the preparation of an electrochemical immunosensor for ethinylestradiol (EE2) based on grafting of diazonium salt of 4-aminobenzoic acid onto a glassy carbon electrode modified with silver nanoparticles/SiO2/graphene oxide hybrid followed by covalent binding of anti-ethinylestradiol (anti-EE2) to activated carboxyl groups. A competitive immunoassay was developed for the determination of the hormone using peroxidase-labeled ethinylestradiol (HRP-EE2) and measurement of the amperometric response at -200mV in the presence of hydroquinone (HQ) as redox mediator. The calibration curve for EE2 exhibited a linear range between 0.1 and 50ng/mL (r(2)=0.996), with a detection limit of 65pg/mL. Interference studies with other hormones related with EE2 revealed the practical specificity of the developed method for the analyte. A good reproducibility, with RSD=4.5% (n=10) was also observed. The operating stability of a single bioelectrode modified with anti-EE2 was maintained at least for 15 days when it was stored at 4°C under humid conditions between measurements. The developed immunosensor was applied to the analysis of spiked urine with good results. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Self-assembled monolayers-based immunosensor for detection of Escherichia coli using electrochemical impedance spectroscopy

    International Nuclear Information System (INIS)

    Geng Ping; Zhang Xinai; Meng Weiwei; Wang Qingjiang; Zhang Wen; Jin Litong; Feng Zhen; Wu Zirong

    2008-01-01

    An electrochemical impedance immunosensor for the detection of Escherichia coli was developed by immobilizing anti-E. coli antibodies at an Au electrode. The immobilization of antibodies at the Au electrode was carried out through a stable acyl amino ester intermediate generated by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydrosuccinimide (NHS), which could condense antibodies reproducibly and densely on the self-assembled monolayer (SAM). The surface characteristics of the immunosensor before and after the binding reaction of antibodies with E. coli were characterized by atomic force microscopy (AFM). The immobilization of antibodies and the binding of E. coli cells to the electrode could increase the electro-transfer resistance, which was directly detected by electrochemical impedance spectroscopy (EIS) in the presence of Fe(CN) 6 3- /Fe(CN) 6 4- as a redox probe. A linear relationship between the electron-transfer resistance and the logarithmic value of E. coli concentration was found in the range of E. coli cells from 3.0 x 10 3 to 3.0 x 10 7 cfu mL -1 with the detection limit of 1.0 x 10 3 cfu mL -1 . With preconcentration and pre-enrichment steps, it was possible to detect E. coli concentration as low as 50 cfu/mL in river water samples

  15. Portable amperometric immunosensor for histamine detection using Prussian blue-chitosan-gold nanoparticle nanocomposite films.

    Science.gov (United States)

    Dong, Xiu-Xiu; Yang, Jin-Yi; Luo, Lin; Zhang, Yi-Feng; Mao, Chuanbin; Sun, Yuan-Ming; Lei, Hong-Tao; Shen, Yu-Dong; Beier, Ross C; Xu, Zhen-Lin

    2017-12-15

    Histamine (HA) is a biogenic amine that can accumulate to high concentration levels in food as a result of microbial activity and can cause toxic effects in consumers. In this work, a portable electrochemical immunosensor capable of detecting HA with high sensitivity and selectivity was developed. Prussian blue-chitosan-gold nanoparticle (PB-CS-AuNP) nanocomposite films with excellent biocompatibility were synthesized and characterized by scanning electron microscopy and energy dispersive X-ray analysis. The PB-CS-AuNP were coated onto a screen-printed electrode by one-step electrodeposition and used to conjugate the HA ovalbumin conjugate (HA-Ag). HA was determined by a competition between the coating HA-Ag and the HRP labeled HA antibody (HRP-HA-Ab). After careful optimization of assay conditions and Box-Behnken analysis, the developed immunosensor showed a linear range from 0.01 to 100μg/mL for HA in fish samples. The average recoveries from spiked samples ranged from 97.25% to 105%. The biosensor also showed good specificity, reproducibility, and stability, indicating its potential application in monitoring HA in a simple and low cost manner. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. A Sandwich HIV p24 Amperometric Immunosensor Based on a Direct Gold Electroplating-Modified Electrode

    Directory of Open Access Journals (Sweden)

    Ning Gan

    2012-05-01

    Full Text Available Acquired immune deficiency syndrome (AIDS is a severe communicable immune deficiency disease caused by the human immune deficiency virus (HIV. The analysis laboratory diagnosis of HIV infection is a crucial aspect of controlling AIDS. The p24 antigen, the HIV-1 capsid protein, is of considerable diagnostic interest because it is detectable several days earlier than host-generated HIV antibodies following HIV exposure. We present herein a new sandwich HIV p24 immunosensor based on directly electroplating an electrode surface with gold nanoparticles using chronoamperometry, which greatly increased the conductivity and reversibility of the electrode. Under optimum conditions, the electrochemical signal showed a linear relationship with the concentration of p24, ranging from 0.01 ng/mL to 100 ng/mL (R > 0.99, and the detection limit was 0.008 ng/mL. Compared with ELISA, this method increased the sensitivity by more than two orders of magnitude (the sensitivity of ELISA for p24 is about 1 ng/mL. This immunosensor may be broadly applied to clinical samples, being distinguished by its ease of use, mild reaction conditions, guaranteed reproducibility, and good anti-interference ability.

  17. A sandwich HIV p24 amperometric immunosensor based on a direct gold electroplating-modified electrode.

    Science.gov (United States)

    Zheng, Lei; Jia, Liyong; Li, Bo; Situ, Bo; Liu, Qinlan; Wang, Qian; Gan, Ning

    2012-05-18

    Acquired immune deficiency syndrome (AIDS) is a severe communicable immune deficiency disease caused by the human immune deficiency virus (HIV). The analysis laboratory diagnosis of HIV infection is a crucial aspect of controlling AIDS. The p24 antigen, the HIV-1 capsid protein, is of considerable diagnostic interest because it is detectable several days earlier than host-generated HIV antibodies following HIV exposure. We present herein a new sandwich HIV p24 immunosensor based on directly electroplating an electrode surface with gold nanoparticles using chronoamperometry, which greatly increased the conductivity and reversibility of the electrode. Under optimum conditions, the electrochemical signal showed a linear relationship with the concentration of p24, ranging from 0.01 ng/mL to 100 ng/mL (R > 0.99), and the detection limit was 0.008 ng/mL. Compared with ELISA, this method increased the sensitivity by more than two orders of magnitude (the sensitivity of ELISA for p24 is about 1 ng/mL). This immunosensor may be broadly applied to clinical samples, being distinguished by its ease of use, mild reaction conditions, guaranteed reproducibility, and good anti-interference ability.

  18. A membrane-based immunosensor for the analysis of the herbicide isoproturon.

    Science.gov (United States)

    Baskeyfield, Damian E H; Davis, Frank; Magan, Naresh; Tothill, Ibtisam E

    2011-08-12

    A membrane based heterogeneous competitive enzyme-linked immunosorbent assay (ELISA) was used in this work to develop an immunosensor for the detection of a common herbicide, isoproturon. A screen-printed carbon working electrode with carbon counter and silver-silver chloride pseudo-reference electrode was utilized incorporating a membrane fixed into intimate contact with the working electrode to facilitate signal transduction. The membrane containing an immobilized isoproturon-ovalbumin conjugate was laminated onto the carbon working electrode and horseradish peroxidase (HRP) labeled polyclonal antibody was then applied for the competitive assay. Two different amperometric systems, hydroquinone and o-phenylenediamine (OPD) mediation reduction were utilised and the properties of the resultant sensors were compared. A flow injection apparatus was also developed utilising the immunosensor. Limits of detection for isoproturon (LLD(90)) were found to be as low as 0.84 ng mL(-1). The senor was also validated using spiked extracted soil samples and also isoproturon contaminated samples. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. A photoelectrochemical immunosensor for detection of α-fetoprotein based on Au-ZnO flower-rod heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Han, Zhizhong, E-mail: zzhan@fjmu.edu.cn; Luo, Min; Chen, Li; Chen, Jinghua; Li, Chunyan, E-mail: cyli65@126.com

    2017-04-30

    Highlights: • Au NPs were deposited onto ZnO FRs by cyclic voltammetry methods. • Au NPs were used to enhance light absorption and photo-induced charge separation. • The PEC immunosensor based on Au-ZnO FRs presented a higher photocurrent. • The detection limit of this novel PEC immunosensor was 0.56 pg mL{sup −1} for AFP. - Abstract: In this work, a novel label free photoelectrochemical (PEC) immunosensor has been developed for the detection of α-fetoprotein (AFP). The immunosensor was based on Au-ZnO flower-rods (FRs) heterostructure, where Au nanoparticles (NPs) were firstly electrodeposited by cyclic voltammetry methods. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Mott-Schottky plot (MS), UV–vis diffuse reflectance spectrum and fluorescence emission spectrum were used for the characterizations of Au-ZnO FRs. The results demonstrated that Au NPs not only obviously enhanced the visible light absorption of ZnO FRs due to surface plasmon resonance (SPR) but also improved the separation of photo-generated electron-hole pairs. Therefore, the photocurrent of Au-ZnO FRs was increased under simulated sunlight. The photocurrent was reduced after the specific antibody-antigen immune reaction. And the photocurrent decrement was linear with the logarithm of AFP antigen concentration in the range from 0.005 ng mL{sup −1} to 50 ng mL{sup −1} with a low detection limit of 0.56 pg mL{sup −1} (S/N = 3). The PEC immunosensor also exhibited high anti-interference property and acceptable stability. This work would provide a promising photoelectrochemical strategy for the detection of other proteins in clinical diagnosis.

  20. Electrochemical immunosensors for the detection of survival motor neuron (SMN) protein using different carbon nanomaterials-modified electrodes.

    Science.gov (United States)

    Eissa, Shimaa; Alshehri, Nawal; Rahman, Anas M Abdel; Dasouki, Majed; Abu-Salah, Khalid M; Zourob, Mohammed

    2018-03-15

    Spinal muscular atrophy is an untreatable potentially fatal hereditary disorder caused by loss-of-function mutations in the survival motor neuron (SMN) 1 gene which encodes the SMN protein. Currently, definitive diagnosis relies on the demonstration of biallelic pathogenic variants in SMN1 gene. Therefore, there is an urgent unmet need to accurately quantify SMN protein levels for screening and therapeutic monitoring of symptomatic newborn and SMA patients, respectively. Here, we developed a voltammetric immunosensor for the sensitive detection of SMN protein based on covalently functionalized carbon nanofiber-modified screen printed electrodes. A comparative study of six different carbon nanomaterial-modified electrodes (carbon, graphene (G), graphene oxide (GO), single wall carbon nanotube (SWCNT), multi-wall carbon nanotube (MWCNT), and carbon nanofiber (CNF)) was performed. 4-carboxyphenyl layers were covalently grafted on the six electrodes by electroreduction of diazonium salt. Then, the terminal carboxylic moieties on the electrodes surfaces were utilized to immobilize the SMN antibody via EDC/NHS chemistry and to fabricate the immunosensors. The electrochemical characterization and analytical performance of the six immunosensors suggest that carbon nanofiber is a better electrode material for the SMN immunosensor. The voltammetric SMN carbon nanofiber-based immunosensor showed high sensitivity (detection limit of 0.75pg/ml) and selectivity against other proteins such as cystic fibrosis transmembrane conductance regulator (CFTR) and dystrophin (DMD). We suggest that this novel biosensor is superior to other developed assays for SMN detection in terms of lower cost, higher sensitivity, simplicity and capability of high throughput screening. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. A photoelectrochemical immunosensor for detection of α-fetoprotein based on Au-ZnO flower-rod heterostructures

    International Nuclear Information System (INIS)

    Han, Zhizhong; Luo, Min; Chen, Li; Chen, Jinghua; Li, Chunyan

    2017-01-01

    Highlights: • Au NPs were deposited onto ZnO FRs by cyclic voltammetry methods. • Au NPs were used to enhance light absorption and photo-induced charge separation. • The PEC immunosensor based on Au-ZnO FRs presented a higher photocurrent. • The detection limit of this novel PEC immunosensor was 0.56 pg mL"−"1 for AFP. - Abstract: In this work, a novel label free photoelectrochemical (PEC) immunosensor has been developed for the detection of α-fetoprotein (AFP). The immunosensor was based on Au-ZnO flower-rods (FRs) heterostructure, where Au nanoparticles (NPs) were firstly electrodeposited by cyclic voltammetry methods. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Mott-Schottky plot (MS), UV–vis diffuse reflectance spectrum and fluorescence emission spectrum were used for the characterizations of Au-ZnO FRs. The results demonstrated that Au NPs not only obviously enhanced the visible light absorption of ZnO FRs due to surface plasmon resonance (SPR) but also improved the separation of photo-generated electron-hole pairs. Therefore, the photocurrent of Au-ZnO FRs was increased under simulated sunlight. The photocurrent was reduced after the specific antibody-antigen immune reaction. And the photocurrent decrement was linear with the logarithm of AFP antigen concentration in the range from 0.005 ng mL"−"1 to 50 ng mL"−"1 with a low detection limit of 0.56 pg mL"−"1 (S/N = 3). The PEC immunosensor also exhibited high anti-interference property and acceptable stability. This work would provide a promising photoelectrochemical strategy for the detection of other proteins in clinical diagnosis.

  2. FET immunosensor for hemoglobin A1c using a gold nanofilm grown by a seed-mediated technique and covered with mixed self-assembled monolayers

    International Nuclear Information System (INIS)

    Xue, Q.; Bian, C.; Tong, J.; Sun, J.; Zhang, H.; Xia, S.

    2012-01-01

    A micro FET-based immunosensor was developed for the determination of hemoglobin-A1c (HbA1c). The HbA1c/hemoglobin ratio is an important index in diabetes control. The sensor was fabricated by Complementary Metal-Oxide-Semiconductor Transistor (CMOS) and Micro Electronic Mechanical System (MEMS) techniques. The antibodies were immobilized via mixed self-assembled monolayers (SAMs) on a gold nanofilm. The nanofilm was deposited on a gold electrode by seed-mediated growth and gave a uniform and well distributed coverage. Nonspecific sites and interferences by noise were eliminated by covering the AuNPs with mixed SAMs. Compared to the immunosensor fabricated via the mixed SAMs method without gold nanofilm, the immunosensor displays a more than 2-fold sensitivity. The immunosensor is capable of detecting HbA1c and hemoglobin in hemolyzed and diluted whole blood, and results showed good agreement with the established clinical method. (author)

  3. Uranium - what role

    International Nuclear Information System (INIS)

    Grey, T.; Gaul, J.; Crooks, P.; Robotham, R.

    1980-01-01

    Opposing viewpoints on the future role of uranium are presented. Topics covered include the Australian Government's uranium policy, the status of nuclear power around the world, Australia's role as a uranium exporter and problems facing the nuclear industry

  4. Brazilian uranium exploration program

    International Nuclear Information System (INIS)

    Marques, J.P.M.

    1981-01-01

    General information on Brazilian Uranium Exploration Program, are presented. The mineralization processes of uranium depoits are described and the economic power of Brazil uranium reserves is evaluated. (M.C.K.) [pt

  5. Uranium enrichment

    International Nuclear Information System (INIS)

    1991-11-01

    This paper analyzes under four different scenarios the adequacy of a $500 million annual deposit into a fund to pay for the cost of cleaning up the Department of Energy's (DOE) three aging uranium enrichment plants. These plants are located in Oak Ridge, Tennessee; Paducah, Kentucky; and Portsmouth, Ohio. In summary the following was found: A fixed annual $500 million deposit made into a cleanup fund would not be adequate to cover total expected cleanup costs, nor would it be adequate to cover expected decontamination and decommissioning (D and D) costs. A $500 million annual deposit indexed to an inflation rate would likely be adequate to pay for all expected cleanup costs, including D and D costs, remedial action, and depleted uranium costs

  6. Uranium production

    International Nuclear Information System (INIS)

    Spriggs, M.

    1980-01-01

    The balance between uranium supply and demand is examined. Should new resources become necessary, some unconventional sources which could be considered include low-grade extensions to conventional deposits, certain types of intrusive rock, tuffs, and lake and sea-bed sediments. In addition there are large but very low grade deposits in carbonaceous shales, granites, and seawater. The possibility of recovery is discussed. Programmes of research into the feasibility of extraction of uranium from seawater, as a by-product from phosphoric acid production, and from copper leach solutions, are briefly discussed. Other possible sources are coal, old mine dumps and tailings, the latter being successfully exploited commercially in South Africa. The greatest constraints on increased development of U from lower grade sources are economics and environmental impact. It is concluded that apart from U as a by-product from phosphate, other sources are unlikely to contribute much to world requirements in the foreseeable future. (U.K.)

  7. Uranium enrichment

    International Nuclear Information System (INIS)

    1991-08-01

    This paper reports that in 1990 the Department of Energy began a two-year project to illustrate the technical and economic feasibility of a new uranium enrichment technology-the atomic vapor laser isotope separation (AVLIS) process. GAO believes that completing the AVLIS demonstration project will provide valuable information about the technical viability and cost of building an AVLIS plant and will keep future plant construction options open. However, Congress should be aware that DOE still needs to adequately demonstrate AVLIS with full-scale equipment and develop convincing cost projects. Program activities, such as the plant-licensing process, that must be completed before a plant is built, could take many years. Further, an updated and expanded uranium enrichment analysis will be needed before any decision is made about building an AVLIS plant. GAO, which has long supported legislation that would restructure DOE's uranium enrichment program as a government corporation, encourages DOE's goal of transferring AVLIS to the corporation. This could reduce the government's financial risk and help ensure that the decision to build an AVLIS plant is based on commercial concerns. DOE, however, has no alternative plans should the government corporation not be formed. Further, by curtailing a planned public access program, which would have given private firms an opportunity to learn about the technology during the demonstration project, DOE may limit its ability to transfer AVLIS to the private sector

  8. An electrochemical immunosensor for brain natriuretic peptide prepared with screen-printed carbon electrodes nanostructured with gold nanoparticles grafted through aryl diazonium salt chemistry.

    Science.gov (United States)

    Serafín, V; Torrente-Rodríguez, R M; González-Cortés, A; García de Frutos, P; Sabaté, M; Campuzano, S; Yáñez-Sedeño, P; Pingarrón, J M

    2018-03-01

    A sensitive amperometric immunosensor has been prepared by immobilization of capture antibodies onto gold nanoparticles (AuNPs) grafted on a screen-printed carbon electrode (SPCE) through aryl diazonium salt chemistry using 4-aminothiophenol (AuNPs-S-Phe-SPCE). The immunosensor was designed for the accurate determination of clinically relevant levels of B-type natriuretic peptide (BNP) in human serum samples. The nanostructured electrochemical platform resulted in an ordered layer of AuNPs onto SPCEs which combined the advantages of high conductivity and improved stability of immobilized biomolecules. The resulting disposable immunosensor used a sandwich type immunoassay involving a peroxidase-labeled detector antibody. The amperometric transduction was carried out at -0.20V (vs the Ag pseudo-reference electrode) upon the addition of hydroquinone (HQ) as electron transfer mediator and H 2 O 2 as the enzyme substrate. The nanostructured immunosensors show a storage stability of at least 25 days, a linear range between 0.014 and 15ngmL -1 , and a LOD of 4pgmL -1 , which is 100 times lower than the established cut-off value for heart failure (HF) diagnosis. The performance of the immunosensor is advantageously compared with that provided with immunosensors prepared by grafting SPCE with p-phenylendiamine (H 2 N-Phe-SPCE) and attaching AuNPs by immersion into an AuNPs suspension or by electrochemical deposition, as well as with immunosensors constructed using commercial AuNPs-modified SPCEs. The developed immunosensor was applied to the successful analysis of human serum from heart failure (HF) patients upon just a 10-times dilution as sample treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Derived enriched uranium market

    International Nuclear Information System (INIS)

    Rutkowski, E.

    1996-01-01

    The potential impact on the uranium market of highly enriched uranium from nuclear weapons dismantling in the Russian Federation and the USA is analyzed. Uranium supply, conversion, and enrichment factors are outlined for each country; inventories are also listed. The enrichment component and conversion components are expected to cause little disruption to uranium markets. The uranium component of Russian derived enriched uranium hexafluoride is unresolved; US legislation places constraints on its introduction into the US market

  10. Uranium industry annual, 1986

    International Nuclear Information System (INIS)

    1987-01-01

    Uranium industry data collected in the EIA-858 survey provide a comprehensive statistical characterization of annual activities of the industry and include some information about industry plans over the next several years. This report consists of two major sections. The first addresses uranium raw materials activities and covers the following topics: exploration activities and expenditures, resources and reserves, mine production of uranium, production of uranium concentrate, and industry employment. The second major section is concerned with the following uranium marketing activities: uranium purchase commitments, uranium prices, procurement arrangements, uranium imports and exports, enrichment services, inventories, secondary market activities utility market requirements and related topics

  11. Uranium Industry. Annual 1984

    International Nuclear Information System (INIS)

    Lawrence, M.S.S.

    1985-01-01

    This report provides a statistical description of activities of the US uranium industry during 1984 and includes a statistical profile of the status of the industry at the end of 1984. It is based on the results of an Energy Information Administration (EIA) survey entitled ''Uranium Industry Annual Survey'' (Form EIA-858). The principal findings of the survey are summarized under two headings - Uranium Raw Materials Activities and Uranium Marketing Activities. The first heading covers exploration and development, uranium resources, mine and mill production, and employment. The second heading covers uranium deliveries and delivery commitments, uranium prices, foreign trade in uranium, inventories, and other marketing activities. 32 figs., 48 tabs

  12. Simultaneous analysis of uranium and nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Bostick, D.T.

    1978-04-01

    A direct spectrophotometric method has been developed for the determination of 20 to 200 g/l of uranium in the presence of 3 to 5 M nitric acid. A dual-wavelength analysis is used to eliminate the enhancing effect of nitrate ion on the uranium visible spectra. The precision and accuracy of the simultaneous analysis of uranium and nitrate were compared using combinations of the four uranium wavelength maxima, occurring at 426, 416, 403 and 359 nm. Calculations based on 426 and 416 nm data yielded the most accurate results. The calculated relative standard deviation of uranium and nitrate concentrations was 5.4 percent and 15.5 percent, respectively. The photometric procedure is slightly affected by temperature; an increase of one degree centigrade results in a 0.2 g/l overestimation of uranium concentration. Because the method is non-destructive, it is directly applicable to the continuous in-line analysis of dissolved uranium in aqueous fuel reprocessing streams.

  13. Multiplexed determination of human growth hormone and prolactin at a label free electrochemical immunosensor using dual carbon nanotube-screen printed electrodes modified with gold and PEDOT nanoparticles.

    Science.gov (United States)

    Serafín, V; Martínez-García, G; Agüí, L; Yáñez-Sedeño, P; Pingarrón, J M

    2014-09-21

    A label-free dual electrochemical immunosensor was constructed for the multiplexed determination of human growth (hGH) and prolactin (PRL) hormones. The immunosensor used an electrochemical platform composed of carbon nanotube-screen printed carbon electrodes (CNT/SPCEs) modified with poly(ethylene-dioxythiophene) (PEDOT) and gold nanoparticles, on which the corresponding hGH and PRL antibodies were immobilized. The affinity reactions were monitored by measuring the decrease in the differential pulse voltammetric oxidation response of the redox probe dopamine. The experimental variables involved in the preparation of both AuNP/PEDOT/CNT/SPC modified electrodes and the dual immunosensor were optimized. The immunosensor exhibited an improved analytical performance for hGH and PRL with respect to other electrochemical immunosensor designs, showing wide ranges of linearity and low detection limits of 4.4 and 0.22 pg mL(-1), respectively. An excellent selectivity against other hormones and in the presence of ascorbic and uric acids was found. The usefulness of the dual immunosensor for the simultaneous analysis of hGH and PRL was demonstrated by analyzing human serum and saliva samples spiked with the hormones at different concentration levels.

  14. Uranium price reporting systems

    International Nuclear Information System (INIS)

    1987-09-01

    This report describes the systems for uranium price reporting currently available to the uranium industry. The report restricts itself to prices for U 3 O 8 natural uranium concentrates. Most purchases of natural uranium by utilities, and sales by producers, are conducted in this form. The bulk of uranium in electricity generation is enriched before use, and is converted to uranium hexafluoride, UF 6 , prior to enrichment. Some uranium is traded as UF 6 or as enriched uranium, particularly in the 'secondary' market. Prices for UF 6 and enriched uranium are not considered directly in this report. However, where transactions in UF 6 influence the reported price of U 3 O 8 this influence is taken into account. Unless otherwise indicated, the terms uranium and natural uranium used here refer exclusively to U 3 O 8 . (author)

  15. Uranium Industry Annual, 1992

    International Nuclear Information System (INIS)

    1993-01-01

    The Uranium Industry Annual provides current statistical data on the US uranium industry for the Congress, Federal and State agencies, the uranium and electric utility industries, and the public. The feature article, ''Decommissioning of US Conventional Uranium Production Centers,'' is included. Data on uranium raw materials activities including exploration activities and expenditures, resources and reserves, mine production of uranium, production of uranium concentrate, and industry employment are presented in Chapter 1. Data on uranium marketing activities including domestic uranium purchases, commitments by utilities, procurement arrangements, uranium imports under purchase contracts and exports, deliveries to enrichment suppliers, inventories, secondary market activities, utility market requirements, and uranium for sale by domestic suppliers are presented in Chapter 2

  16. Uranium Industry Annual, 1992

    Energy Technology Data Exchange (ETDEWEB)

    1993-10-28

    The Uranium Industry Annual provides current statistical data on the US uranium industry for the Congress, Federal and State agencies, the uranium and electric utility industries, and the public. The feature article, ``Decommissioning of US Conventional Uranium Production Centers,`` is included. Data on uranium raw materials activities including exploration activities and expenditures, resources and reserves, mine production of uranium, production of uranium concentrate, and industry employment are presented in Chapter 1. Data on uranium marketing activities including domestic uranium purchases, commitments by utilities, procurement arrangements, uranium imports under purchase contracts and exports, deliveries to enrichment suppliers, inventories, secondary market activities, utility market requirements, and uranium for sale by domestic suppliers are presented in Chapter 2.

  17. Provision by the uranium and uranium products

    International Nuclear Information System (INIS)

    Elagin, Yu.P.

    2005-01-01

    International uranium market is converted from the buyer market into the seller market. The prices of uranium are high and the market attempts to adapt to changing circumstances. The industry of uranium enrichment satisfies the increasing demands but should to increase ots capacities. On the whole the situation is not stable and every year may change the existing position [ru

  18. Uranium recovery from slags of metallic uranium

    International Nuclear Information System (INIS)

    Fornarolo, F.; Frajndlich, E.U.C.; Durazzo, M.

    2006-01-01

    The Center of the Nuclear Fuel of the Institute of Nuclear Energy Research - IPEN finished the program of attainment of fuel development for research reactors the base of Uranium Scilicet (U 3 Si 2 ) from Hexafluoride of Uranium (UF 6 ) with enrichment 20% in weight of 235 U. In the process of attainment of the league of U 3 Si 2 we have as Uranium intermediate product the metallic one whose attainment generates a slag contend Uranium. The present work shows the results gotten in the process of recovery of Uranium in slags of calcined slags of Uranium metallic. Uranium the metallic one is unstable, pyrophoricity and extremely reactive, whereas the U 3 O 8 is a steady oxide of low chemical reactivity, what it justifies the process of calcination of slags of Uranium metallic. The calcination of the Uranium slag of the metallic one in oxygen presence reduces Uranium metallic the U 3 O 8 . Experiments had been developed varying it of acid for Uranium control and excess, nitric molar concentration gram with regard to the stoichiometric leaching reaction of temperature of the leaching process. The 96,0% income proves the viability of the recovery process of slags of Uranium metallic, adopting it previous calcination of these slags in nitric way with low acid concentration and low temperature of leaching. (author)

  19. Uranium enrichment

    International Nuclear Information System (INIS)

    Mohrhauer, H.

    1982-01-01

    The separation of uranium isotopes in order to enrich the fuel for light water reactors with the light isotope U-235 is an important part of the nuclear fuel cycle. After the basic principals of isotope separation the gaseous diffusion and the centrifuge process are explained. Both these techniques are employed on an industrial scale. In addition a short review is given on other enrichment techniques which have been demonstrated at least on a laboratory scale. After some remarks on the present situation on the enrichment market the progress in the development and the industrial exploitation of the gas centrifuge process by the trinational Urenco-Centec organisation is presented. (orig.)

  20. Uranium conversion; Urankonvertering

    Energy Technology Data Exchange (ETDEWEB)

    Oliver, Lena; Peterson, Jenny; Wilhelmsen, Katarina [Swedish Defence Research Agency (FOI), Stockholm (Sweden)

    2006-03-15

    FOI, has performed a study on uranium conversion processes that are of importance in the production of different uranium compounds in the nuclear industry. The same conversion processes are of interest both when production of nuclear fuel and production of fissile material for nuclear weapons are considered. Countries that have nuclear weapons ambitions, with the intention to produce highly enriched uranium for weapons purposes, need some degree of uranium conversion capability depending on the uranium feed material available. This report describes the processes that are needed from uranium mining and milling to the different conversion processes for converting uranium ore concentrate to uranium hexafluoride. Uranium hexafluoride is the uranium compound used in most enrichment facilities. The processes needed to produce uranium dioxide for use in nuclear fuel and the processes needed to convert different uranium compounds to uranium metal - the form of uranium that is used in a nuclear weapon - are also presented. The production of uranium ore concentrate from uranium ore is included since uranium ore concentrate is the feed material required for a uranium conversion facility. Both the chemistry and principles or the different uranium conversion processes and the equipment needed in the processes are described. Since most of the equipment that is used in a uranium conversion facility is similar to that used in conventional chemical industry, it is difficult to determine if certain equipment is considered for uranium conversion or not. However, the chemical conversion processes where UF{sub 6} and UF{sub 4} are present require equipment that is made of corrosion resistant material.

  1. Issues in uranium availability

    International Nuclear Information System (INIS)

    Schanz, J.J. Jr.; Adams, S.S.; Gordon, R.L.

    1982-01-01

    The purpose of this publication is to show the process by which information about uranium reserves and resources is developed, evaluated and used. The following three papers in this volume have been abstracted and indexed for the Energy Data Base: (1) uranium reserve and resource assessment; (2) exploration for uranium in the United States; (3) nuclear power, the uranium industry, and resource development

  2. Australian uranium industry

    Energy Technology Data Exchange (ETDEWEB)

    Warner, R K

    1976-04-01

    Various aspects of the Australian uranium industry are discussed including the prospecting, exploration and mining of uranium ores, world supply and demand, the price of uranium and the nuclear fuel cycle. The market for uranium and the future development of the industry are described.

  3. Irradiated uranium reprocessing

    International Nuclear Information System (INIS)

    Gal, I.

    1961-12-01

    Task concerned with reprocessing of irradiated uranium covered the following activities: implementing the method and constructing the cell for uranium dissolving; implementing the procedure for extraction of uranium, plutonium and fission products from radioactive uranium solutions; studying the possibilities for using inorganic ion exchangers and adsorbers for separation of U, Pu and fission products

  4. Uranium processing and properties

    CERN Document Server

    2013-01-01

    Covers a broad spectrum of topics and applications that deal with uranium processing and the properties of uranium Offers extensive coverage of both new and established practices for dealing with uranium supplies in nuclear engineering Promotes the documentation of the state-of-the-art processing techniques utilized for uranium and other specialty metals

  5. Recovering uranium from phosphates

    Energy Technology Data Exchange (ETDEWEB)

    Bergeret, M [Compagnie de Produits Chimiques et Electrometallurgiques Pechiney-Ugine Kuhlmann, 75 - Paris (France)

    1981-06-01

    Processes for the recovery of the uranium contained in phosphates have today become competitive with traditional methods of working uranium sources. These new possibilities will make it possible to meet more rapidly any increases in the demand for uranium: it takes ten years to start working a new uranium deposit, but only two years to build a recovery plant.

  6. Uranium enrichment plans

    International Nuclear Information System (INIS)

    Gagne, R.W.; Thomas, D.C.

    1977-01-01

    The status of existing uranium enrichment contracts in the US is reviewed and expected natural uranium requirements for existing domestic uranium enrichment contracts are evaluated. Uncertainty in natural uranium requirements associated with requirements-type and fixed-commitment type contracts is discussed along with implementation of variable tails assay

  7. Uranium enrichment plans

    International Nuclear Information System (INIS)

    Thomas, D.C.; Gagne, R.W.

    1978-01-01

    The following topics are covered: the status of the Government's existing uranium enrichment services contracts, natural uranium requirements based on the latest contract information, uncertainty in predicting natural uranium requirements based on uranium enrichment contracts, and domestic and foreign demand assumed in enrichment planning

  8. SPR based immunosensor for detection of Legionella pneumophila in water samples

    Science.gov (United States)

    Enrico, De Lorenzis; Manera, Maria G.; Montagna, Giovanni; Cimaglia, Fabio; Chiesa, Maurizio; Poltronieri, Palmiro; Santino, Angelo; Rella, Roberto

    2013-05-01

    Detection of legionellae by water sampling is an important factor in epidemiological investigations of Legionnaires' disease and its prevention. To avoid labor-intensive problems with conventional methods, an alternative, highly sensitive and simple method is proposed for detecting L. pneumophila in aqueous samples. A compact Surface Plasmon Resonance (SPR) instrumentation prototype, provided with proper microfluidics tools, is built. The developed immunosensor is capable of dynamically following the binding between antigens and the corresponding antibody molecules immobilized on the SPR sensor surface. A proper immobilization strategy is used in this work that makes use of an important efficient step aimed at the orientation of antibodies onto the sensor surface. The feasibility of the integration of SPR-based biosensing setups with microfluidic technologies, resulting in a low-cost and portable biosensor is demonstrated.

  9. Uranium industry annual 1985

    International Nuclear Information System (INIS)

    1986-11-01

    This report consists of two major sections. The first addresses uranium raw materials activities and covers the following topics: exploration activities and expenditures, resources and reserves, mine production of uranium, production of uranium concentrate, and industry employment. The second major section is concerned with the following uranium marketing activities: uranium purchase commitments, uranium prices, procurement arrangements, uranium imports and exports, enrichment services, inventories, secondary market activities, utility market requirements, and related topics. A glossary and appendices are included to assist the reader in interpreting the substantial array of statistical data in this report and to provide background information about the survey

  10. Uranium industry framework

    International Nuclear Information System (INIS)

    Riley, K.

    2008-01-01

    The global uranium market is undergoing a major expansion due to an increase in global demand for uranium, the highest uranium prices in the last 20 years and recognition of the potential greenhouse benefits of nuclear power. Australia holds approximately 27% of the world's uranium resources (recoverable at under US$80/kg U), so is well placed to benefit from the expansion in the global uranium market. Increasing exploration activity due to these factors is resulting in the discovery and delineation of further high grade uranium deposits and extending Australia's strategic position as a reliable and safe supplier of low cost uranium.

  11. Reduction of uranium hexafluoride to uranium tetrafluoride

    International Nuclear Information System (INIS)

    Chang, I.S.; Do, J.B.; Choi, Y.D.; Park, M.H.; Yun, H.H.; Kim, E.H.; Kim, Y.W.

    1982-01-01

    The single step continuous reduction of uranium hexafluoride (UF 6 ) to uranium tetrafluoride (UF 4 ) has been investigated. Heat required to initiate and maintain the reaction in the reactor is supplied by the highly exothermic reaction of hydrogen with a small amount of elemental fluorine which is added to the uranium hexafluoride stream. When gases uranium hexafluoride and hydrogen react in a vertical monel pipe reactor, the green product, UF 4 has 2.5g/cc in bulk density and is partly contaminated by incomplete reduction products (UF 5 ,U 2 F 9 ) and the corrosion product, presumably, of monel pipe of the reactor itself, but its assay (93% of UF 4 ) is acceptable for the preparation of uranium metal with magnesium metal. Remaining problems are the handling of uranium hexafluoride, which is easily clogging the flowmeter and gas feeding lines because of extreme sensitivity toward moisture, and a development of gas nozzel for free flow of uranium hexafluoride gas. (Author)

  12. Uranium - the world picture

    International Nuclear Information System (INIS)

    Silver, J.M.; Wright, W.J.

    1976-01-01

    The world resources of uranium and the future demand for uranium are discussed. The amount of uranium available depends on the price which users are prepared to pay for its recovery. As the price is increased, there is an incentive to recover uranium from lower grade or more difficult deposits. In view of this, attention is drawn to the development of the uranium industry in Australias

  13. Comparison of Electrochemical Immunosensors and Aptasensors for Detection of Small Organic Molecules in Environment, Food Safety, Clinical and Public Security

    Directory of Open Access Journals (Sweden)

    Benoit Piro

    2016-02-01

    Full Text Available We review here the most frequently reported targets among the electrochemical immunosensors and aptasensors: antibiotics, bisphenol A, cocaine, ochratoxin A and estradiol. In each case, the immobilization procedures are described as well as the transduction schemes and the limits of detection. It is shown that limits of detections are generally two to three orders of magnitude lower for immunosensors than for aptasensors, due to the highest affinities of antibodies. No significant progresses have been made to improve these affinities, but transduction schemes were improved instead, which lead to a regular improvement of the limit of detections corresponding to ca. five orders of magnitude over these last 10 years. These progresses depend on the target, however.

  14. A self-amplified transistor immunosensor under dual gate operation: highly sensitive detection of hepatitis B surface antigen

    Science.gov (United States)

    Lee, I.-K.; Jeun, M.; Jang, H.-J.; Cho, W.-J.; Lee, K. H.

    2015-10-01

    Ion-sensitive field-effect transistors (ISFETs), although they have attracted considerable attention as effective immunosensors, have still not been adopted for practical applications owing to several problems: (1) the poor sensitivity caused by the short Debye screening length in media with high ion concentration, (2) time-consuming preconditioning processes for achieving the highly-diluted media, and (3) the low durability caused by undesirable ions such as sodium chloride in the media. Here, we propose a highly sensitive immunosensor based on a self-amplified transistor under dual gate operation (immuno-DG ISFET) for the detection of hepatitis B surface antigen. To address the challenges in current ISFET-based immunosensors, we have enhanced the sensitivity of an immunosensor by precisely tailoring the nanostructure of the transistor. In the pH sensing test, the immuno-DG ISFET showed superior sensitivity (2085.53 mV per pH) to both standard ISFET under single gate operation (58.88 mV per pH) and DG ISFET with a non-tailored transistor (381.14 mV per pH). Moreover, concerning the detection of hepatitis B surface antigens (HBsAg) using the immuno-DG ISFET, we have successfully detected trace amounts of HBsAg (22.5 fg mL-1) in a non-diluted 1× PBS medium with a high sensitivity of 690 mV. Our results demonstrate that the proposed immuno-DG ISFET can be a biosensor platform for practical use in the diagnosis of various diseases.Ion-sensitive field-effect transistors (ISFETs), although they have attracted considerable attention as effective immunosensors, have still not been adopted for practical applications owing to several problems: (1) the poor sensitivity caused by the short Debye screening length in media with high ion concentration, (2) time-consuming preconditioning processes for achieving the highly-diluted media, and (3) the low durability caused by undesirable ions such as sodium chloride in the media. Here, we propose a highly sensitive immunosensor

  15. A novel photoelectrochemical immunosensor by integration of nanobody and TiO₂ nanotubes for sensitive detection of serum cystatin C.

    Science.gov (United States)

    Mi, Li; Wang, Pingyan; Yan, Junrong; Qian, Jing; Lu, Jusheng; Yu, Jiachao; Wang, Yuzhen; Liu, Hong; Zhu, Min; Wan, Yakun; Liu, Songqin

    2016-01-01

    Cystatin C (CysC) is a sensitive marker for the estimation of the glomerular filtration rate and the clinical diagnosis of different diseases. In this paper, CysC-specific nanobodies (Nbs) were isolated from a phage display nanobody library. A simple and sensitive photoelectrochemical immunosensor based on TiO2 nanotube arrays (TNAs) was proposed for the sensitive detection of CysC. The TiO2 nanotube arrays deposited by electrochemical anodization displayed a high and stable photocurrent response under irradiation. After coupling CysC-specific nanobody to TNA (Nb/TNA), the proposed immunosensor for CysC can be utilized for tracking the photocurrent change of Nb/TNA caused by immunoreactions between CysC and the immobilized CysC-specific Nb. This allowed for the determination of CysC with a calibration range from 0.72 pM to 7.19 nM. The variation of the photocurrent was in a linear relationship with the logarithm of the CysC concentration in the range of 0.72 pM-3.6 nM. The immunosensor had a correlation coefficient of 0.97 and a detection limit of 0.14 pM at a signal-to-noise ratio of 3. The proposed immunosensor showed satisfactory intra- and inter-assay accuracy, high selectivity and good stability. As a result, this proposed strategy would offer a novel and simple approach for the detection of immunoreactions, provide new insights in popularizing the diagnosis of CysC, and extend the application of TiO2 nanotubes. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Coreactant-free and Label-free Eletrochemiluminescence Immunosensor for Copeptin Based on Luminescent Immuno-Gold Nanoassemblys.

    Science.gov (United States)

    Han, Zhili; Shu, Jiangnan; Jiang, Qiaoshi; Cui, Hua

    2018-04-25

    In this work, the eletrochemiluminescence (ECL) behavior of Cu 2+ /cysteine complexes and N-(aminobutyl)-N-(ethylisoluminol) (ABEI) functionalized gold nanoparticles combined with chitosan (Cu 2+ -Cys-ABEI-GNPs-CS) were studied by cyclic voltammetry and a double-step potential, which exhibited excellent ECL properties without any coreactant. It was found that the ECL intensity of Cu 2+ -Cys-ABEI-GNPs-CS could increase at least one order of magnitude compared with that of Cu 2+ -Cys-ABEI-GNPs. Furthermore, a coreactant-free and label-free ECL immunosensor has been established for the determination of early acute myocardial infarction biomarker copeptin based on luminescent immuno-gold nanoassemblys consisting of Cu 2+ -Cys-ABEI-GNPs-CS and immuno-gold nanoparticles prepared by connecting copeptin antibody with trisodium citrate stabilized gold nanoparticles. In the presence of copeptin, an obvious decrease in ECL intensity was observed due to the formation of antibody-antigen immunocomplex, which could be used for the determination of copeptin in the range of 2.0×10 -14 -1.0×10 -11 mol/L with a detection limit of 5.18×10 -15 mol/L. The detection limit of the ECL immunosensor is at least two orders of magnitude lower than that of sandwich immunoassays based on labeling technology. And the ECL immunosensor does not need any coreactant, and avoids complicated labeling and purification procedure. It is ultrasensitive, simple, specific and low-cost. This work reveals that the proposed luminescent immuno-gold nanoassemblys are ideal nanointerfaces for the construction of immunosensors. The proposed strategy may be used for the determination of other antigens if corresponding antibodies are available.

  17. Natural uranium

    International Nuclear Information System (INIS)

    Ammerich, Marc; Frot, Patricia; Gambini, Denis-Jean; Gauron, Christine; Moureaux, Patrick; Herbelet, Gilbert; Lahaye, Thierry; Pihet, Pascal; Rannou, Alain

    2014-08-01

    This sheet belongs to a collection which relates to the use of radionuclides essentially in unsealed sources. Its goal is to gather on a single document the most relevant information as well as the best prevention practices to be implemented. These sheets are made for the persons in charge of radiation protection: users, radioprotection-skill persons, labor physicians. Each sheet treats of: 1 - the radio-physical and biological properties; 2 - the main uses; 3 - the dosimetric parameters; 4 - the measurement; 5 - the protection means; 6 - the areas delimitation and monitoring; 7 - the personnel classification, training and monitoring; 8 - the effluents and wastes; 9 - the authorization and declaration administrative procedures; 10 - the transport; and 11 - the right conduct to adopt in case of incident or accident. This sheet deals specifically with natural uranium

  18. A sensitive label–free amperometric immunosensor for alpha-fetoprotein based on gold nanorods with different aspect ratio

    Science.gov (United States)

    Zhou, Chunyang; Liu, Dali; Xu, Lin; Li, Qingling; Song, Jian; Xu, Sai; Xing, Ruiqing; Song, Hongwei

    2015-01-01

    A simple and accurate label–free amperometric immunosensor for α–fetoprotein (AFP) detection is developed based on gold nanorods (GNRs) with different aspect ratio and compared with gold particles (GNPs). The positively charged GNRs and GNPs due to the surface immobilized cetyltrimethyl ammonium bromide (CTAB) can adsorb the negatively charged AFP antibody (Ab) directly. The presence of the GNRs not only enhanced the immobilized amount of biomolecules, but also improved the electrochemical properties of the immunosensor. With the aid of GNRs, the electrochemical signal was greatly enhanced in comparison with GNPs. Under optimal conditions, the proposed immunosensor could detect AFP in a linear range from 0.1 to 200 ng/mL with a detection limit of 0.04 ng/mL (signal–to–noise ratio = 3), and it also possessed good reproducibility and storage stability. Moreover, the detection of AFP in five human serum samples also showed satisfactory accuracy. The proposed methodology was potentially attractive for clinical immunoassay. PMID:25909588

  19. A novel signal-on photoelectrochemical immunosensor for detection of alpha-fetoprotein by in situ releasing electron donor.

    Science.gov (United States)

    Chen, Jiexia; Zhao, Guang-Chao

    2017-12-15

    A signal-on photoelectrochemical (PEC) immunosensor was constructed for detecting tumor marker in this work. α-fetoprotein (AFP) was chosen as a model analyte to investigate the prepared procedure and the analytical performance of the exploited sensor. In order to construct the sensor, CdSe QDs were used as photoactive material, biotin conjugated AFP antibody (Bio-anti-AFP) as detecting probe, streptavidin (SA) as signal capturing unit, biotin functionalized apoferritin encapsulated ascorbic acid (Bio-APOAA) as amplification unit, which were assembled onto the electrodes. The sensing strategy was based on in situ enzymatic hydrolysis of Bio-APOAA to release ascorbic acid (AA) as sacrificial electron donor to produce photocurrent. The photocurrent from the immunosensor was monitored as a result of AFP concentrations. The constructed sensing platform displayed high selectivity and good sensitivity for detecting AFP. Under optimal conditions, a wide linear range from 0.001 to 1000ng/mL and a low detection limit of 0.31pg/mL were obtained. The developed immunosensor is expected to be used to determine AFP and other tumor markers in human plasma in clinical laboratories either for pre-cancer screening or cancer monitoring. Moreover, this sensing platform further has the potential to use for the detection of trypsin activity and the corresponding inhibitor-screening. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. A novel label-free voltammetric immunosensor for the detection of {alpha}-fetoprotein using functional titanium dioxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Liang Wenbin [Chongqing Key Laboratory of Analytical Chemistry, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Yuan Ruo [Chongqing Key Laboratory of Analytical Chemistry, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China)], E-mail: yuanruo@swu.edu.cn; Chai Yaqin; Li Yan; Zhuo Ying [Chongqing Key Laboratory of Analytical Chemistry, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China)

    2008-01-01

    A highly sensitive label-free voltammetric immunosensor was developed based on the functional titanium dioxide nanoparticles (PV-NTiP), which was prepared by capping 1,1'-bis-(2-phosphonoethyl)-4,4'-bipyridinium dibromide (PV) on the surface of the titanium dioxide nanoparticles (NTiP) with covalent attachment. The PV-NTiP has prominent biocompatibility, good electron transfer ability, primarily excellent adsorption, large specific surface area and positively charged environment. As a result, the negatively charged gold nanoparticles (NGP) could be adsorbed on the PV-NTiP modified electrode surface by electrostatic adsorption, and then to immobilize {alpha}-1-fetoprotein antibody (anti-AFP) for the assay of {alpha}-1-fetoprotein (AFP). The fabricated procedures and electrochemical behaviors of the immunosensor were characterized by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and cyclic voltammetry (CV). The anti-AFP/NGP/PV-NTiP modified electrode was sensitive to AFP in linear relation between 1.25 and 200 ng/mL with the correlation coefficient of 0.9982, and the detection limit (S/N = 3) is 0.6 ng/mL under the optimal conditions. In addition, the proposed immunosensor exhibits good sensitivity, selectivity, stability and long-term maintenance of bioactivity and it may be used to immobilize other biomoleculars to develop biosensor for the detection of other antigens or biocompounds.

  1. Label-free immunosensor for the detection of kanamycin using Ag@Fe₃O₄ nanoparticles and thionine mixed graphene sheet.

    Science.gov (United States)

    Yu, Shujun; Wei, Qin; Du, Bin; Wu, Dan; Li, He; Yan, Liangguo; Ma, Hongmin; Zhang, Yong

    2013-10-15

    A highly sensitive label-free immunosensor for the detection of kanamycin had been developed using silver hybridized mesoporous ferroferric oxide nanoparticles (Ag@Fe₃O₄ NPs) and thionine mixed graphene sheet (TH-GS). TH was used as an electron transfer mediator. The electrical signal was greatly improved in the presence of GS due to its good electron-transfer ability. With the advantages of large specific surface area and excellent electrical conductivity, Ag@Fe₃O₄ NPs could immobilize more antibodies of kanamycin and promote the electron transfer. Cyclic voltammetry and square wave voltammetry were used to characterize the recognition of kanamycin. The proposed immunosensor showed good performances such as low detection limit (15 pg mL⁻¹), wide linear range (from 0.050 to 16 ng mL⁻¹), short analysis time (3 min), high stability, and good selectivity in the detection of kanamycin. The immunosensor was evaluated for pork meat sample, receiving satisfactory results. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Enzyme immunosensor based on gold nanoparticles electroposition and Streptavidin-biotin system for detection of S. pullorum and S. gallinarum

    International Nuclear Information System (INIS)

    Hu, Chunmei; Dou, Wenchao; Zhao, Guangying

    2014-01-01

    A novel electrochemical enzyme immunosensor based on the electrodeposited gold nanoparticles and the multistage amplification of streptavidin-biotin affinity system for detection of Salmonella pullorum and Salmonella gallinarum (S. pullorum and S. gallinarum) was investigated in this study. The electrochemical characteristics of the stepwise modified electrodes were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), whereas the determinations of the targets of S. pullorum and S. gallinarum were carried out by CV. As shown in the results of this study, the electron transfer was promoted by the electrodeposition of gold nanoparticles, thus the communication of electrons was enhanced and the conductivity of the electrode was strengthened too. Moreover, the number of the conjugated bio-molecules was elevated greatly by the electrodeposited gold nanoparticles and the streptavidin-biotin, which contributed to the integration of the following modifications and amplification of the current response signal. Under the optimized working conditions, the sensor showed a good performance with a linear response range from 10 2 CFU/ml to10 9 CFU/ml, the detection limit for S. pullorum and S. gallinarum determination was 1.95 × 10 2 CFU/ml (S/N = 3). The proposed enzyme immunosensor with high sensitivity, good specificity, acceptable accuracy and reproducibility, and low detection limit characteristics could be a promising analytical tool in detection of S. pullorum and S. gallinarum in practical samples and a model for the development of immunosensor of other bacterium of interests

  3. Facile preparation of disposable immunosensor for Shigella flexneri based on multi-wall carbon nanotubes/chitosan composite

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Guangying, E-mail: zhaogy-user@163.co [Food Safety Key Lab of Zhejiang Province, Department of Food Quality and Safety, Zhejiang Gongshang University, 149, Jiaogong Road, Hangzhou 310035, Zhejiang Province (China); Zhan Xuejia [Food Safety Key Lab of Zhejiang Province, Department of Food Quality and Safety, Zhejiang Gongshang University, 149, Jiaogong Road, Hangzhou 310035, Zhejiang Province (China)

    2010-02-28

    Based on multi-wall carbon nanotubes (MWCNT)/chitosan/horseradish peroxidase labeled antibodies to Shigella flexneri (HRP-anti-S. flexneri) biocomposite film on a screen-printed electrode (SPE) surface, a disposable immunosensor has been developed for the rapid detection of S. flexneri. The HRP-anti-S. flexneri can be entrapped into MWCNT/chitosan composite matrix without other cross-linking agent. Thionine and H{sub 2}O{sub 2} were used as the mediator and substrate, respectively. The surface morphologies of modified films were characterized by atomic force microscope (AFM). Cyclic voltammery (CV) was carried out to characterize the electrochemical properties of the immobilization of materials on the electrode surface and quantified S. flexneri. Due to the strong electrocatalytic properties of MWCNT and HRP toward H{sub 2}O{sub 2}, the response signal was significantly amplified. S. flexneri could be detected by the decrease of the reduction peak current before and after immunoreaction. Under optimal conditions, S. flexneri could be detected in the range of 10{sup 4} to 10{sup 10} cfu mL{sup -1}, with a detection limit of 2.3 x 10{sup 3} cfu mL{sup -1} (S/N = 3). Furthermore, the proposed immunosensor exhibited a satisfactory specificity, reproducibility, stability and accuracy, indicating that the proposed immunosensor has potential application for a facile, rapid and harmless immunoassay.

  4. Facile preparation of disposable immunosensor for Shigella flexneri based on multi-wall carbon nanotubes/chitosan composite

    International Nuclear Information System (INIS)

    Zhao Guangying; Zhan Xuejia

    2010-01-01

    Based on multi-wall carbon nanotubes (MWCNT)/chitosan/horseradish peroxidase labeled antibodies to Shigella flexneri (HRP-anti-S. flexneri) biocomposite film on a screen-printed electrode (SPE) surface, a disposable immunosensor has been developed for the rapid detection of S. flexneri. The HRP-anti-S. flexneri can be entrapped into MWCNT/chitosan composite matrix without other cross-linking agent. Thionine and H 2 O 2 were used as the mediator and substrate, respectively. The surface morphologies of modified films were characterized by atomic force microscope (AFM). Cyclic voltammery (CV) was carried out to characterize the electrochemical properties of the immobilization of materials on the electrode surface and quantified S. flexneri. Due to the strong electrocatalytic properties of MWCNT and HRP toward H 2 O 2 , the response signal was significantly amplified. S. flexneri could be detected by the decrease of the reduction peak current before and after immunoreaction. Under optimal conditions, S. flexneri could be detected in the range of 10 4 to 10 10 cfu mL -1 , with a detection limit of 2.3 x 10 3 cfu mL -1 (S/N = 3). Furthermore, the proposed immunosensor exhibited a satisfactory specificity, reproducibility, stability and accuracy, indicating that the proposed immunosensor has potential application for a facile, rapid and harmless immunoassay.

  5. Faraday cage-type electrochemiluminescence immunosensor for ultrasensitive detection of Vibrio vulnificus based on multi-functionalized graphene oxide.

    Science.gov (United States)

    Guo, Zhiyong; Sha, Yuhong; Hu, Yufang; Yu, Zhongqing; Tao, Yingying; Wu, Yanjie; Zeng, Min; Wang, Sui; Li, Xing; Zhou, Jun; Su, Xiurong

    2016-10-01

    A novel Faraday cage-type electrochemiluminescence (ECL) immunosensor devoted to the detection of Vibrio vulnificus (VV) was fabricated. The sensing strategy was presented by a unique Faraday cage-type immunocomplex based on immunomagnetic beads (IMBs) and multi-functionalized graphene oxide (GO) labeled with (2,2'-bipyridine)(5-aminophenanthroline)ruthenium (Ru-NH2). The multi-functionalized GO could sit on the electrode surface directly due to the large surface area, abundant functional groups, and good electronic transport property. It ensures that more Ru-NH2 is entirely caged and become "effective," thus improving sensitivity significantly, which resembles extending the outer Helmholtz plane (OHP) of the electrode. Under optimal conditions, the developed immunosensor achieves a limit of detection as low as 1 CFU/mL. Additionally, the proposed immunosensor with high sensitivity and selectivity can be used for the detection of real samples. The novel Faraday cage-type method has shown potential application for the diagnosis of VV and opens up a new avenue in ECL immunoassay. Graphical abstract Faraday cage-type immunoassay mode for ultrasensitive detection by extending OHP.

  6. Uranium management activities

    International Nuclear Information System (INIS)

    Jackson, D.; Marshall, E.; Sideris, T.; Vasa-Sideris, S.

    2001-01-01

    One of the missions of the Department of Energy's (DOE) Oak Ridge Office (ORO) has been the management of the Department's uranium materials. This mission has been accomplished through successful integration of ORO's uranium activities with the rest of the DOE complex. Beginning in the 1980's, several of the facilities in that complex have been shut down and are in the decommissioning process. With the end of the Cold War, the shutdown of many other facilities is planned. As a result, inventories of uranium need to be removed from the Department facilities. These inventories include highly enriched uranium (HEU), low enriched uranium (LEU), normal uranium (NU), and depleted uranium (DU). The uranium materials exist in different chemical forms, including metals, oxides, solutions, and gases. Much of the uranium in these inventories is not needed to support national priorities and programs. (author)

  7. Uranium industry annual 1998

    International Nuclear Information System (INIS)

    1999-01-01

    The Uranium Industry Annual 1998 (UIA 1998) provides current statistical data on the US uranium industry's activities relating to uranium raw materials and uranium marketing. It contains data for the period 1989 through 2008 as collected on the Form EIA-858, ''Uranium Industry Annual Survey.'' Data provides a comprehensive statistical characterization of the industry's activities for the survey year and also include some information about industry's plans and commitments for the near-term future. Data on uranium raw materials activities for 1989 through 1998, including exploration activities and expenditures, EIA-estimated reserves, mine production of uranium, production of uranium concentrate, and industry employment, are presented in Chapter 1. Data on uranium marketing activities for 1994 through 2008, including purchases of uranium and enrichment services, enrichment feed deliveries, uranium fuel assemblies, filled and unfilled market requirements, and uranium inventories, are shown in Chapter 2. The methodology used in the 1998 survey, including data edit and analysis, is described in Appendix A. The methodologies for estimation of resources and reserves are described in Appendix B. A list of respondents to the ''Uranium Industry Annual Survey'' is provided in Appendix C. The Form EIA-858 ''Uranium Industry Annual Survey'' is shown in Appendix D. For the readers convenience, metric versions of selected tables from Chapters 1 and 2 are presented in Appendix E along with the standard conversion factors used. A glossary of technical terms is at the end of the report. 24 figs., 56 tabs

  8. Uranium industry annual 1994

    International Nuclear Information System (INIS)

    1995-01-01

    The Uranium Industry Annual 1994 (UIA 1994) provides current statistical data on the US uranium industry's activities relating to uranium raw materials and uranium marketing during that survey year. The UIA 1994 is prepared for use by the Congress, Federal and State agencies, the uranium and nuclear electric utility industries, and the public. It contains data for the 10-year period 1985 through 1994 as collected on the Form EIA-858, ''Uranium Industry Annual Survey.'' Data collected on the ''Uranium Industry Annual Survey'' (UIAS) provide a comprehensive statistical characterization of the industry's activities for the survey year and also include some information about industry's plans and commitments for the near-term future. Where aggregate data are presented in the UIA 1994, care has been taken to protect the confidentiality of company-specific information while still conveying accurate and complete statistical data. A feature article, ''Comparison of Uranium Mill Tailings Reclamation in the United States and Canada,'' is included in the UIA 1994. Data on uranium raw materials activities including exploration activities and expenditures, EIA-estimated resources and reserves, mine production of uranium, production of uranium concentrate, and industry employment are presented in Chapter 1. Data on uranium marketing activities, including purchases of uranium and enrichment services, and uranium inventories, enrichment feed deliveries (actual and projected), and unfilled market requirements are shown in Chapter 2

  9. Enzyme-free electrochemical immunosensor configured with Au-Pd nanocrystals and N-doped graphene sheets for sensitive detection of AFP.

    Science.gov (United States)

    Zhao, Lifang; Li, Songjun; He, Jing; Tian, Guihong; Wei, Qin; Li, He

    2013-11-15

    A novel electrochemical immunosensor capable of enzyme-free detection of alpha fetoprotein (AFP) is reported. This immunosensor was fabricated in a sandwich-like format where catalytic Au-Pd nanocrystals and highly conductive N-doped graphene sheets were incorporated. The significant catalysis by Au-Pd nanocrystals toward hydrogen peroxide, along with the increased electron transfer by graphene sheets, caused signal generation and increased sensitivity, which enables the enzyme-free detection of AFP. With a low detection limit at 0.005 ng mL(-1), this novel immunosensor worked well over the broad linear range of 0.05-30 ng mL(-1). Unlike previously reported enzyme-based electrochemical immunosensors, which often involve the complicated steps for enzyme loading and necessary treatments to keep the activity of enzyme, this novel immunosensor is simple in nature and employed catalytic Au-Pd nanoparticles and highly conductive graphene, which thus enables reliable and sensitive detection for clinic usage. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Uranium: a basic evaluation

    International Nuclear Information System (INIS)

    Crull, A.W.

    1978-01-01

    All energy sources and technologies, including uranium and the nuclear industry, are needed to provide power. Public misunderstanding of the nature of uranium and how it works as a fuel may jeopardize nuclear energy as a major option. Basic chemical facts about uranium ore and uranium fuel technology are presented. Some of the major policy decisions that must be made include the enrichment, stockpiling, and pricing of uranium. Investigations and lawsuits pertaining to uranium markets are reviewed, and the point is made that oil companies will probably have to divest their non-oil energy activities. Recommendations for nuclear policies that have been made by the General Accounting Office are discussed briefly

  11. Uranium health physics

    International Nuclear Information System (INIS)

    1980-01-01

    This report contains the papers delivered at the Summer School on Uranium Health Physics held in Pretoria on the 14 and 15 April 1980. The following topics were discussed: uranium producton in South Africa; radiation physics; internal dosimetry and radiotoxicity of long-lived uranium isotopes; uranium monitoring; operational experience on uranium monitoring; dosimetry and radiotoxicity of inhaled radon daughters; occupational limits for inhalation of radon-222, radon-220 and their short-lived daughters; radon monitoring techniques; radon daughter dosimeters; operational experience on radon monitoring; and uranium mill tailings management

  12. Uranium: one utility's outlook

    International Nuclear Information System (INIS)

    Gass, C.B.

    1983-01-01

    The perspective of the Arizona Public Service Company (APS) on the uncertainty of uranium as a fuel supply is discussed. After summarizing the history of nuclear power and the uranium industries, a projection is made for the future uranium market. An uncrtain uranium market is attributed to various determining factors that include international politics, production costs, non-commercial government regulation, production-company stability, and questionable levels of uranium sales. APS offers its solutions regarding type of contract, choice of uranium producers, pricing mechanisms, and aids to the industry as a whole. 5 references, 10 figures, 1 table

  13. Recovery of uranium from crude uranium tetrafluoride

    International Nuclear Information System (INIS)

    Ghosh, S.K.; Bellary, M.P.; Keni, V.S.

    1994-01-01

    An innovative process has been developed for recovery of uranium from crude uranium tetrafluoride cake. The process is based on direct dissolution of uranium tetrafluoride in nitric acid in presence of aluminium hydroxide and use of solvent extraction for removal of fluorides and other bulk impurities to make uranium amenable for refining. It is a simple process requiring minimum process step and has advantage of lesser plant corrosion. This process can be applied for processing of uranium tetrafluoride generated from various sources like uranium by-product during thorium recovery from thorium concentrate, first stage product of uranium recovery from phosphoric acid by OPPA process and off grade uranium tetrafluoride material. The paper describes the details of the process developed and demonstrated on bench and pilot scale and its subsequent modification arising out of bulky solid waste generation. The modified process uses a lower quantity of aluminium hydroxide by allowing a lower dissolution of uranium per cycle and recycles the undissolved material to the next cycle, maintaining the overall recovery at high level. This innovation has reduced the solid waste generated by a factor of four at the cost of a slightly larger dissolution vessel and its increased corrosion rate. (author)

  14. Recovery of uranium from crude uranium tetrafluoride

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, S K; Bellary, M P; Keni, V S [Chemical Engineering Division, Bhabha Atomic Research Centre, Mumbai (India)

    1994-06-01

    An innovative process has been developed for recovery of uranium from crude uranium tetrafluoride cake. The process is based on direct dissolution of uranium tetrafluoride in nitric acid in presence of aluminium hydroxide and use of solvent extraction for removal of fluorides and other bulk impurities to make uranium amenable for refining. It is a simple process requiring minimum process step and has advantage of lesser plant corrosion. This process can be applied for processing of uranium tetrafluoride generated from various sources like uranium by-product during thorium recovery from thorium concentrate, first stage product of uranium recovery from phosphoric acid by OPPA process and off grade uranium tetrafluoride material. The paper describes the details of the process developed and demonstrated on bench and pilot scale and its subsequent modification arising out of bulky solid waste generation. The modified process uses a lower quantity of aluminium hydroxide by allowing a lower dissolution of uranium per cycle and recycles the undissolved material to the next cycle, maintaining the overall recovery at high level. This innovation has reduced the solid waste generated by a factor of four at the cost of a slightly larger dissolution vessel and its increased corrosion rate. (author). 4 refs., 1 fig., 3 tabs.

  15. Uranium production

    International Nuclear Information System (INIS)

    Jones, J.Q.

    1981-01-01

    The domestic uranium industry is in a state of stagflation. Costs continue to rise while the market for the product remains stagnant. During the last 12 months, curtailments and closures of mines and mills have eliminated over 5000 jobs in the industry, plus many more in those industries that furnish supplies and services. By January 1982, operations at four mills and the mines that furnish them ore will have been terminated. Other closures may follow, depending on cost trends, duration of current contracts, the degree to which mills have been amortized, the feasibility of placing mines on standby, the grade of the ore, and many other factors. Open-pit mines can be placed on standby without much difficulty, other than the possible cost of restoration before all the ore has been removed. There are a few small, dry, underground mines that could be mothballed; however, the major underground producers are wet sandstone mines that in most cases could not be reopened after a prolonged shutdown; mills can be mothballed for several years. Figure 8 shows the location of all the production centers in operation, as well as those that have operated or are on standby. Table 1 lists the same production centers plus those that have been deferred, showing nominal capacity of conventional mills in tons of ore per calendar day, and the industry production rate for those mills as of October 1, 1981

  16. Uranium mining in Australia

    International Nuclear Information System (INIS)

    Anon.

    1980-01-01

    Known uranium deposits and the companies involved in uranium mining and exploration in Australia are listed. The status of the development of the deposits is outlined and reasons for delays to mining are given

  17. Uranium Processing Facility

    Data.gov (United States)

    Federal Laboratory Consortium — An integral part of Y‑12's transformation efforts and a key component of the National Nuclear Security Administration's Uranium Center of Excellence, the Uranium...

  18. Uranium in Niger

    International Nuclear Information System (INIS)

    Gabelmann, E.

    1978-03-01

    This document presents government policy in the enhancement of uranium resources, existing mining companies and their productions, exploitation projects and economical outcome related to the uranium mining and auxiliary activities [fr

  19. Price of military uranium

    International Nuclear Information System (INIS)

    Klimenko, A.V.

    1998-01-01

    The theoretical results about optimum strategy of use of military uranium confirmed by systems approach accounts are received. The numerical value of the system approach price of the highly enriched military uranium also is given

  20. Uranium market and resources

    International Nuclear Information System (INIS)

    Capus, G.; Arnold, Th.

    2004-01-01

    The controversy about the extend of the uranium resources worldwide is still important, this article sheds some light on this topic. Every 2 years IAEA and NEA (nuclear energy agency) edit an inventory of uranium resources as reported by contributing countries. It appears that about 4.6 millions tons of uranium are available at a recovery cost less than 130 dollars per kg of uranium and a total of 14 millions tons of uranium can be assessed when including all existing or supposed resources. In fact there is enough uranium to sustain a moderate growth of the park of nuclear reactors during next decades and it is highly likely that the volume of uranium resources can allow a more aggressive development of nuclear energy. It is recalled that a broad use of the validated breeder technology can stretch the durability of uranium resources by a factor 50. (A.C.)

  1. Uranium from phosphate ores

    International Nuclear Information System (INIS)

    Hurst, F.J.

    1983-01-01

    The following topics are described briefly: the way phosphate fertilizers are made; how uranium is recovered in the phosphate industry; and how to detect covert uranium recovery operations in a phsophate plant

  2. Industrial realities: Uranium

    International Nuclear Information System (INIS)

    Thiron, H.

    1990-01-01

    In this special issue are examined ores and metals in France and in the world for 1988. The chapter on uranium gives statistical data on the uranium market: Demand, production, prices and reserves [fr

  3. Brazilian uranium deposits

    International Nuclear Information System (INIS)

    Santos, L.C.S. dos.

    1985-01-01

    Estimatives of uranium reserves carried out in Figueira, Itataia, Lagoa Real and Espinharas, in Brazil are presented. The samples testing allowed to know geological structures, and the characteristics of uranium mineralization. (M.C.F.) [pt

  4. Uranium mining in Australia

    International Nuclear Information System (INIS)

    Anon.

    1984-01-01

    The mining of uranium in Australia is criticised in relation to it's environmental impact, economics and effects on mine workers and Aborigines. A brief report is given on each of the operating and proposed uranium mines in Australia

  5. Uranium mining in Australia

    International Nuclear Information System (INIS)

    Mackay, G.A.

    1978-01-01

    Western world requirements for uranium based on increasing energy consumption and a changing energy mix, will warrant the development of Australia's resources. By 1985 Australian mines could be producing 9500 tonnes of uranium oxide yearly and by 1995 the export value from uranium could reach that from wool. In terms of benefit to the community the economic rewards are considerable but, in terms of providing energy to the world, Australias uranium is vital

  6. Radiation damage of uranium

    International Nuclear Information System (INIS)

    Lazarevic, Dj.

    1966-11-01

    Study of radiation damage covered the following: Kinetics of electric resistance of uranium and uranium alloy with 1% of molybdenum dependent on the second phase and burnup rate; Study of gas precipitation and diffusion of bubbles by transmission electron microscopy; Numerical analysis of the influence of defects distribution and concentration on the rare gas precipitation in uranium; study of thermal sedimentation of uranium alloy with molybdenum; diffusion of rare gas in metal by gas chromatography method

  7. Bicarbonate leaching of uranium

    International Nuclear Information System (INIS)

    Mason, C.

    1998-01-01

    The alkaline leach process for extracting uranium from uranium ores is reviewed. This process is dependent on the chemistry of uranium and so is independent on the type of mining system (conventional, heap or in-situ) used. Particular reference is made to the geochemical conditions at Crownpoint. Some supporting data from studies using alkaline leach for remediation of uranium-contaminated sites is presented

  8. Bicarbonate leaching of uranium

    Energy Technology Data Exchange (ETDEWEB)

    Mason, C.

    1998-12-31

    The alkaline leach process for extracting uranium from uranium ores is reviewed. This process is dependent on the chemistry of uranium and so is independent on the type of mining system (conventional, heap or in-situ) used. Particular reference is made to the geochemical conditions at Crownpoint. Some supporting data from studies using alkaline leach for remediation of uranium-contaminated sites is presented.

  9. Uranium in fossil bones

    International Nuclear Information System (INIS)

    Koul, S.L.

    1978-01-01

    An attempt has been made to determine the uranium content and thus the age of certain fossil bones Haritalyangarh (Himachal Pradesh), India. The results indicate that bones rich in apatite are also rich in uranium, and that the radioactivity is due to radionuclides in the uranium series. The larger animals apparently have a higher concentration of uranium than the small. The dating of a fossil jaw (elephant) places it in the Pleistocene. (Auth.)

  10. Electrochemical Immunosensor for the Detection of Aflatoxin B1 in Palm Kernel Cake and Feed Samples

    Directory of Open Access Journals (Sweden)

    Farah Asilah Azri

    2017-11-01

    Full Text Available Palm kernel cake (PKC is the solid residue following oil extraction of palm kernels and useful to fatten animals either as a single feed with only minerals and vitamins supplementation, or mixed with other feedstuffs such as corn kernels or soy beans. The occurrence of mycotoxins (aflatoxins, ochratoxins, zearalenone, and fumonisins in feed samples affects the animal’s health and also serves as a secondary contamination to humans via consumption of eggs, milk and meats. Of these, aflatoxin B1 (AFB1 is the most toxically potent and a confirmed carcinogen to both humans and animals. Methods such as High Performance Liquid Chromatography (HPLC and Liquid Chromatography–Mass Spectrometry (LC-MS/MS are common in the determination of mycotoxins. However, these methods usually require sample pre-treatment, extensive cleanup and skilled operator. Therefore, in the present work, a rapid method of electrochemical immunosensor for the detection of AFB1 was developed based on an indirect competitive enzyme-linked immunosorbent assay (ELISA. Multi-walled carbon nanotubes (MWCNT and chitosan (CS were used as the electrode modifier for signal enhancement. N-ethyl-N′-(3-dimethylaminopropyl-carbodiimide (EDC and N-hydroxysuccinimide (NHS activated the carboxyl groups at the surface of nanocomposite for the attachment of AFB1-BSA antigen by covalent bonding. An indirect competitive reaction occurred between AFB1-BSA and free AFB1 for the binding site of a fixed amount of anti-AFB1 antibody. A catalytic signal based on horseradish peroxidase (HRP in the presence of hydrogen peroxide (H2O2 and 3,3′,5,5′-tetramethylbenzidine (TMB mediator was observed as a result of attachment of the secondary antibody to the immunoassay system. As a result, the reduction peak of TMB(Ox was measured by using differential pulse voltammetry (DPV analysis. Based on the results, the electrochemical surface area was increased from 0.396 cm2 to 1.298 cm2 due to the electrode

  11. Electrochemical Immunosensor for the Detection of Aflatoxin B₁ in Palm Kernel Cake and Feed Samples.

    Science.gov (United States)

    Azri, Farah Asilah; Selamat, Jinap; Sukor, Rashidah

    2017-11-30

    Palm kernel cake (PKC) is the solid residue following oil extraction of palm kernels and useful to fatten animals either as a single feed with only minerals and vitamins supplementation, or mixed with other feedstuffs such as corn kernels or soy beans. The occurrence of mycotoxins (aflatoxins, ochratoxins, zearalenone, and fumonisins) in feed samples affects the animal's health and also serves as a secondary contamination to humans via consumption of eggs, milk and meats. Of these, aflatoxin B₁ (AFB₁) is the most toxically potent and a confirmed carcinogen to both humans and animals. Methods such as High Performance Liquid Chromatography (HPLC) and Liquid Chromatography-Mass Spectrometry (LC-MS/MS) are common in the determination of mycotoxins. However, these methods usually require sample pre-treatment, extensive cleanup and skilled operator. Therefore, in the present work, a rapid method of electrochemical immunosensor for the detection of AFB₁ was developed based on an indirect competitive enzyme-linked immunosorbent assay (ELISA). Multi-walled carbon nanotubes (MWCNT) and chitosan (CS) were used as the electrode modifier for signal enhancement. N -ethyl- N '-(3-dimethylaminopropyl)-carbodiimide (EDC) and N -hydroxysuccinimide (NHS) activated the carboxyl groups at the surface of nanocomposite for the attachment of AFB₁-BSA antigen by covalent bonding. An indirect competitive reaction occurred between AFB₁-BSA and free AFB₁ for the binding site of a fixed amount of anti-AFB₁ antibody. A catalytic signal based on horseradish peroxidase (HRP) in the presence of hydrogen peroxide (H₂O₂) and 3,3',5,5'-tetramethylbenzidine (TMB) mediator was observed as a result of attachment of the secondary antibody to the immunoassay system. As a result, the reduction peak of TMB (Ox) was measured by using differential pulse voltammetry (DPV) analysis. Based on the results, the electrochemical surface area was increased from 0.396 cm² to 1.298 cm² due to the

  12. Method for converting uranium oxides to uranium metal

    International Nuclear Information System (INIS)

    Duerksen, W.K.

    1988-01-01

    A method for converting uranium oxide to uranium metal is described comprising the steps of heating uranium oxide in the presence of a reducing agent to a temperature sufficient to reduce the uranium oxide to uranium metal and form a heterogeneous mixture of a uranium metal product and oxide by-products, heating the mixture in a hydrogen atmosphere at a temperature sufficient to convert uranium metal in the mixture to uranium hydride, cooling the resulting uranium hydride-containing mixture to a temperature sufficient to produce a ferromagnetic transition in the uranium hydride, magnetically separating the cooled uranium hydride from the mixture, and thereafter heating the separated uranium hydride in an inert atmosphere to a temperature sufficient to convert the uranium hydride to uranium metal

  13. Microbial accumulation of uranium

    International Nuclear Information System (INIS)

    Zhang Wei; Dong Faqin; Dai Qunwei

    2005-01-01

    The mechanism of microbial accumulation of uranium and the effects of some factors (including pH, initial uranium concentration, pretreatment of bacteria, and so on) on microbial accumulation of uranium are discussed briefly. The research direction and application prospect are presented. (authors)

  14. Uranium energy dependence

    International Nuclear Information System (INIS)

    Erkes, P.

    1981-06-01

    Uranium supply and demand as projected by the Uranium Institute is discussed. It is concluded that for the industrialized countries, maximum energy independence is a necessity. Hence it is necessary to achieve assurance of supply for uranium used in thermal power reactors in current programs and eventually to move towards breeders

  15. Australian uranium today

    International Nuclear Information System (INIS)

    Fisk, B.

    1978-01-01

    The subject is covered in sections, entitled: Australia's resources; Northern Territory uranium in perspective; the government's decision [on August 25, 1977, that there should be further development of uranium under strictly controlled conditions]; Government legislation; outlook [for the Australian uranium mining industry]. (U.K.)

  16. Uranium resources, 1983

    International Nuclear Information System (INIS)

    1983-01-01

    The specific character of uranium as energy resources, the history of development of uranium resources, the production and reserve of uranium in the world, the prospect regarding the demand and supply of uranium, Japanese activity of exploring uranium resources in foreign countries and the state of development of uranium resources in various countries are reported. The formation of uranium deposits, the classification of uranium deposits and the reserve quantity of each type are described. As the geological environment of uranium deposits, there are six types, that is, quartz medium gravel conglomerate deposit, the deposit related to the unconformity in Proterozoic era, the dissemination type magma deposit, pegmatite deposit and contact deposit in igneaus rocks and metamorphic rocks, vein deposit, sandstone type deposit and the other types of deposit. The main features of respective types are explained. The most important uranium resources in Japan are those in the Tertiary formations, and most of the found reserve belongs to this type. The geological features, the state of yield and the scale of the deposits in Ningyotoge, Tono and Kanmon Mesozoic formation are reported. Uranium minerals, the promising districts in the world, and the matters related to the exploration and mining of uranium are described. (Kako, I.)

  17. Recycling of reprocessed uranium

    International Nuclear Information System (INIS)

    Randl, R.P.

    1987-01-01

    Since nuclear power was first exploited in the Federal Republic of Germany, the philosophy underlying the strategy of the nuclear fuel cycle has been to make optimum use of the resource potential of recovered uranium and plutonium within a closed fuel cycle. Apart from the weighty argument of reprocessing being an important step in the treatment and disposal of radioactive wastes, permitting their optimum ecological conditioning after the reprocessing step and subsequent storage underground, another argument that, no doubt, carried weight was the possibility of reducing the demand of power plants for natural uranium. In recent years, strategies of recycling have emerged for reprocessed uranium. If that energy potential, too, is to be exploited by thermal recycling, it is appropriate to choose a slightly different method of recycling from the one for plutonium. While the first generation of reprocessed uranium fuel recycled in the reactor cuts down natural uranium requirement by some 15%, the recycling of a second generation of reprocessed, once more enriched uranium fuel helps only to save a further three per cent of natural uranium. Uranium of the second generation already carries uranium-232 isotope, causing production disturbances, and uranium-236 isotope, causing disturbances of the neutron balance in the reactor, in such amounts as to make further fabrication of uranium fuel elements inexpedient, even after mixing with natural uranium feed. (orig./UA) [de

  18. High loading uranium plate

    International Nuclear Information System (INIS)

    Wiencek, T.C.; Domagala, R.F.; Thresh, H.R.

    1990-01-01

    Two embodiments of a high uranium fuel plate are disclosed which contain a meat comprising structured uranium compound confined between a pari of diffusion bonded ductile metal cladding plates uniformly covering the meat, the meat hiving a uniform high fuel loading comprising a content of uranium compound greater than about 45 Vol. % at a porosity not greater than about 10 Vol. %. In a first embodiment, the meat is a plurality of parallel wires of uranium compound. In a second embodiment, the meat is a dispersion compact containing uranium compound. The fuel plates are fabricated by a hot isostatic pressing process

  19. PROCESS OF RECOVERING URANIUM

    Science.gov (United States)

    Carter, J.M.; Larson, C.E.

    1958-10-01

    A process is presented for recovering uranium values from calutron deposits. The process consists in treating such deposits to produce an oxidlzed acidic solution containing uranium together with the following imparities: Cu, Fe, Cr, Ni, Mn, Zn. The uranium is recovered from such an impurity-bearing solution by adjusting the pH of the solution to the range 1.5 to 3.0 and then treating the solution with hydrogen peroxide. This results in the precipitation of uranium peroxide which is substantially free of the metal impurities in the solution. The peroxide precipitate is then separated from the solution, washed, and calcined to produce uranium trioxide.

  20. Sensitivity Improvement of an Impedimetric Immunosensor Using Functionalized Iron Oxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    Imen Hafaid

    2009-01-01

    Full Text Available This work has explored the development of impedimetric immunosensors based on magnetic iron nanoparticles (IrNP functionalized with streptavidin to which a biotinylated FAB part of the antibody has been bound using a biotin-streptavidin interaction. SPR analysis shows a deviation on the measured (angle during antigen-antibody recognition whereas label free detection using by EIS allows us to monitor variation of polarization resistance. Before detection, layers were analyzed by FTIR and AFM. Compared to immobilization of antibody on bare gold surface using aminodecanethiol SAM, antibody immobilization on nanoparticles permitted to reach lower detection limit: 500 pg/ml instead of 1 ng/ml to in the case of EIS and 300 ng/ml instead of 4.5 μg/ml in the case of SPR. Thus, it permitted to improve the sensitivity: from 257.3  Ω⋅cm2⋅μg−1⋅ml to 1871 Ω⋅cm2⋅μg−1⋅ml in the case of EIS and from 0.003°μg−1⋅ml to 0.094°μg−1⋅ml in the case of SPR.

  1. An automatic enzyme immunoassay based on a chemiluminescent lateral flow immunosensor.

    Science.gov (United States)

    Joung, Hyou-Arm; Oh, Young Kyoung; Kim, Min-Gon

    2014-03-15

    Microfluidic integrated enzyme immunosorbent assay (EIA) sensors are efficient systems for point-of-care testing (POCT). However, such systems are not only relatively expensive but also require a complicated manufacturing process. Therefore, additional fluidic control systems are required for the implementation of EIAs in a lateral flow immunosensor (LFI) strip sensor. In this study, we describe a novel LFI for EIA, the use of which does not require additional steps such as mechanical fluidic control, washing, or injecting. The key concept relies on a delayed-release effect of chemiluminescence substrates (luminol enhancer and hydrogen peroxide generator) by an asymmetric polysulfone membrane (ASPM). When the ASPM was placed between the nitrocellulose (NC) membrane and the substrate pad, substrates encapsulated in the substrate pad were released after 5.3 ± 0.3 min. Using this delayed-release effect, we designed and implemented the chemiluminescent LFI-based automatic EIA system, which sequentially performed the immunoreaction, pH change, substrate release, hydrogen peroxide generation, and chemiluminescent reaction with only 1 sample injection. In a model study, implementation of the sensor was validated by measuring the high sensitivity C-reactive protein (hs-CRP) level in human serum. © 2013 Elsevier B.V. All rights reserved.

  2. Polymeric Flexible Immunosensor Based on Piezoresistive Micro-Cantilever with PEDOT/PSS Conductive Layer

    Directory of Open Access Journals (Sweden)

    Rui Zhao

    2018-02-01

    Full Text Available In this paper, a fully polymeric micro-cantilever with the surface passivation layer of parylene-C and the strain resistor of poly(3,4-ethylenedioxythiophene/poly (styrene sulfonate (PEDOT/PSS was proposed and demonstrated for immunoassays. By optimizing the design and fabrication of the polymeric micro-cantilever, a square resistance of 220 Ω/□ for PEDOT/PSS conductive layer have been obtained. The experimental spring constant and the deflection sensitivity were measured to be 0.017 N/m and 8.59 × 10−7 nm−1, respectively. The biological sensing performances of polymeric micro-cantilever were investigated by the immunoassay for human immunoglobulin G (IgG. The immunosensor was experimentally demonstrated to have a linear behavior for the detection of IgG within the concentrations of 10~100 ng/mL with a limit of detection (LOD of 10 ng/mL. The experimental results indicate that the proposed polymeric flexible conductive layer-based sensors are capable of detecting trace biological substances.

  3. Study of immunoglobulin G thin layers obtained by the Langmuir-Blodgett method: application to immunosensors.

    Science.gov (United States)

    Barraud, A; Perrot, H; Billard, V; Martelet, C; Therasse, J

    1993-01-01

    Nowadays, immunosensors play a leading part in the field of bioanalytical chemistry research. As with any biosensor, they need appropriate transducers and a suitable technique to immobilize the active biocomponents. In this study, two transduction modes were chosen: mass effects (quartz microbalance measurements) and geometric and dielectric effects (capacitance measurements). The Langmuir-Blodgett (LB) method appears to be quite suitable for generating biospecific surfaces. This work has focused on the detection of staphylococcal enterotoxin B, the corresponding antibody being immobilized at the surface of fatty acids by a variant of the LB method. The composition of the film and the nature of antibody-fatty acid interactions were studied by means of the two transducers mentioned above. FTIR (Fourier transform infra-red) spectroscopy and protein diagnostic assay. Influence of several parameters (pH, ionic strength, transfer pressure, antibody concentration in the subphase) was investigated. The immobilization rate reached its maximum when experimental conditions allowed optimal electrostatic interactions. In this case, the quartz crystal microbalance response, in air, reached 55 Hz per monolayer of immobilized immunoglobulin G and the equivalent capacitance variation, measured in liquid media, was around 300 pF cm-2. Activity of the biospecific LB films, when binding enterotoxin, was checked by the classical ELISA (enzyme immuno-linked assay) technique.

  4. Diagnosis of schistosomiasis japonica with interfacial co-assembly-based multi-channel electrochemical immunosensor arrays

    Science.gov (United States)

    Deng, Wangping; Xu, Bin; Hu, Haiyan; Li, Jianyong; Hu, Wei; Song, Shiping; Feng, Zheng; Fan, Chunhai

    2013-05-01

    Schistosomiasis control remains to be an important and challenging task in the world. However, lack of quick, simple, sensitive and specific sero-diagnostic test is still a hurdle in the control practice. The commonly employed enzyme-linked immuno-sorbent assay (ELISA) relies on the native soluble egg antigen (SEA) that is limited in supply. Here we developed an electrochemical immunosensor array (ECISA) assay with an interfacial co-assembly strategy. A recombinant Schistosoma japonicum (Sj) calcium-binding protein (SjE16) was used as a principal antigen, while the SEA as a minor, co-assembling agent, with a ratio of 8:1 (SjE16: SEA, Sj16EA), which was co-immobilized on a disposable 16-channel screen-printed carbon electrode array. A portable electrochemical detector was employed to detect antibodies in serum samples. The sensitivity of ECISA reached 100% with minimal cross-reactions. Therefore, we have demonstrated that this rapid, sensitive and specific ECISA technique has the potential to perform large-scale on-site screening of Sj infection.

  5. Cost-effective disposable thiourea film modified copper electrode for capacitive immunosensor

    International Nuclear Information System (INIS)

    Limbut, Warakorn; Thavarungkul, Panote; Kanatharana, Proespichaya; Wongkittisuksa, Booncharoen; Asawatreratanakul, Punnee; Limsakul, Chusak

    2010-01-01

    Cost-effective disposable electrodes were fabricated from copper clad laminate, usually used for printed circuit board (PCB) in electronic industries, by using dry film photoresist. Electro-oxidation (anodisation) was employed to obtain a good formation of thiourea film on the electrode surface. The affinity binding pair of carcinoembryonic antigen (CEA) and anti-carcinoembryonic antigen (anti-CEA) was used as a model system. Anti-CEA was immobilized on thiourea film via covalent coupling. This modified electrode was incorporated with a capacitive system for CEA analysis. This capacitive immunosensor provided a linear range between 0.01 and 10 ng ml -1 with a detection limit of 10 pg ml -1 . When applied to analyze CEA in serum samples, the results agreed well with the enzyme linked fluorescent assay (ELFA) technique (P > 0.05). The proposed strategy for the preparation of disposable modified copper electrode is very cost effective and simple. Moreover, it provides good reproducibility. This technique can easily be applied to immobilize other biological sensing elements for biosensors development.

  6. A Miniaturized Impedimetric Immunosensor for the Competitive Detection of Adrenocorticotropic Hormone

    Directory of Open Access Journals (Sweden)

    Nan Li

    2017-12-01

    Full Text Available Adrenocorticotropic hormone (ACTH plays an essential role in regulating corticosteroid hormone production, which has important functions in a myriad of critical physiological functions. In this proof-of-concept study, a miniaturized immunosensor was developed for the highly sensitive detection of ACTH using electrochemical impedance spectroscopy (EIS in connection with disposable screen-printed gold electrodes (SPGEs. A film of 3,3′-dithiobis[sulfosuccinimidylpropionate] (DTSSP was prepared to immobilize anti-ACTH antibodies covalently on the nanostructured SPGE surface. The surface-immobilized anti-ACTH antibodies captured the biotinylated ACTH (biotin-ACTH and non-labelled ACTH for the competitive immunoassay. After coupling of a streptavidin-alkaline phosphatase conjugate (Streptavidin-ALP, the bio-catalysed precipitation of an insoluble and insulating product onto the sensing interface changed the charge transfer resistance (Rct characteristics significantly. The detection limit of 100 fg/mL was determined for ACTH in a 5 μL sample volume, which indicated that this versatile platform can be easily adapted for miniaturized electrochemical immunosensing of cancer marker biomolecules. High selectivity and sensitivity of our immunoassay to detect ACTH in real samples demonstrated its promising potential for future development and applications using clinical samples.

  7. Development of an enrofloxacin immunosensor based on label-free electrochemical impedance spectroscopy.

    Science.gov (United States)

    Wu, Ching-Chou; Lin, Chia-Hung; Wang, Way-Shyan

    2009-06-30

    Enrofloxacin is the most widespread antibiotic in the fluoroquinolone family. As such, the development of a rapid and sensitive method for the determination of trace amounts of enrofloxacin is an important issue in the health field. The interaction of the enrofloxacin antigen to a specific antibody (Ab) immobilized on an 11-mercapto-undecanoic acid-coated gold electrode was quantified by electrochemical impedance spectroscopy. Two equivalent circuits were separately used to interpret the obtained impedance spectra. These circuits included one resistor in series with one parallel circuit comprised of a resistor and a capacitor (1R//C), and one resistor in series with two parallel RC circuits (2R//C). The results indicate that the antigen-antibody reaction analyzed using the 1R//C circuit provided a more sensitive resistance increment against the enrofloxacin concentration than that of the 2R//C circuit. However, the 2R//C circuit provided a better fitting for impedance spectra, and therefore supplies more detailed results of the enrofloxacin-antibody interaction, causing the increase of electron transfer resistance selectively to the modified layer, and not the electrical double layer. The antibody-modified electrode allowed for analysis of the dynamic linear range of 1-1000 ng/ml enrofloxacin with a detection limit of 1 ng/ml. The reagentless and label-free impedimetric immunosensors provide a simple and sensitive detection method for the specific determination of enrofloxacin.

  8. Analytical Application of Flow Immunosensor in Detection of Thyroxine and Triiodothyronine in Serum.

    Science.gov (United States)

    Wani, Tanveer A; Zargar, Seema; Majid, Salma; Darwish, Ibrahim A

    2016-11-01

    In this study, an immunosensor based on kinetic exclusion analysis (KinExA) was used for thyroxine (T4) and triiodothyronine (T3) estimation. A KinExA™ 3200 instrument was used for this analysis, which is an automated flow fluorimeter designed to separate free unbound antibody binding sites in reaction mixtures of antibody, antigen, and antibody-antigen complex. A T3-BSA- and T4-BSA-coated polymethyl methacrylate (PMMA) bead microcolumn is generated inside the flow cell of the instrument. A sample mixture containing T3 and T4 with their respective monoclonal antibodies and their complexes are drawn past the microbead column. The unbound T3 or T4 monoclonal antibody binding sites are captured by their respective T3 and T4 antigens coated on the PMMA beads as bovine serum albumin conjugates. Fluorescently labeled secondary antibodies bind to the T3 or T4 antigen-antibody complex to generate fluorescence intensity for analysis. The limit of detection for the T3 and T4 assays was found to be 0.06 and 1.9 ng mL -1 with acceptable precision values. The convenience of the automated KinExA format may be valuable in medical diagnostic laboratories.

  9. Quantitative differentiation of multiple virus in blood using nanoporous silicon oxide immunosensor and artificial neural network.

    Science.gov (United States)

    Chakraborty, W; Ray, R; Samanta, N; RoyChaudhuri, C

    2017-12-15

    In spite of the rapid developments in various nanosensor technologies, it still remains challenging to realize a reliable ultrasensitive electrical biosensing platform which will be able to detect multiple viruses in blood simultaneously with a fairly high reproducibility without using secondary labels. In this paper, we have reported quantitative differentiation of Hep-B and Hep-C viruses in blood using nanoporous silicon oxide immunosensor array and artificial neural network (ANN). The peak frequency output (f p ) from the steady state sensitivity characteristics and the first cut off frequency (f c ) from the transient characteristics have been considered as inputs to the multilayer ANN. Implementation of several classifier blocks in the ANN architecture and coupling them with both the sensor chips, functionalized with Hep-B and Hep-C antibodies have enabled the quantification of the viruses with an accuracy of around 95% in the range of 0.04fM-1pM and with an accuracy of around 90% beyond 1pM and within 25nM in blood serum. This is the most sensitive report on multiple virus quantification using label free method. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Multielement surface plasmon resonance immunosensor for monitoring of blood circulation system

    Science.gov (United States)

    Kostyukevych, Sergey A.; Kostyukevych, Kateryna V.; Khristosenko, Roman V.; Lysiuk, Viktor O.; Koptyukh, Anastasiya A.; Moscalenko, Nadiya L.

    2017-12-01

    The problems related to the development of a multielement immunosensor device with the prism type of excitation of a surface plasmon resonance in the Kretschmann configuration and with the scanning of the incidence angle of monochromatic light aimed at the reliable determination of the levels of three molecular markers of the system of hemostasis (fibrinogen, soluble fibrin, and D-dimer) are considered. We have analyzed the influence of a technology for the production of a gold coating, modification of its surface, and noise effects on the enhancement of sensitivity and stability of the operation of devices. A means of oriented immobilization of monoclonal antibodies on the surface of gold using a multilayer film of copper aminopentacyanoferrate is developed. For the model proteins of studied markers, the calibrating curves (maximum sensitivity of 0.5 μg/ml) are obtained, and the level of fibrinogen in blood plasma of donors is determined. A four-channel modification of the device with an application of a reference channel for comparing the elimination of the noise of temperature fluctuations has been constructed. This device allows one to execute the express-diagnostics of prethrombotic states and the monitoring of the therapy of diseases of the blood circulation system.

  11. Polymeric Flexible Immunosensor Based on Piezoresistive Micro-Cantilever with PEDOT/PSS Conductive Layer.

    Science.gov (United States)

    Zhao, Rui; Sun, Ying

    2018-02-03

    In this paper, a fully polymeric micro-cantilever with the surface passivation layer of parylene-C and the strain resistor of poly(3,4-ethylenedioxythiophene)/poly (styrene sulfonate) (PEDOT/PSS) was proposed and demonstrated for immunoassays. By optimizing the design and fabrication of the polymeric micro-cantilever, a square resistance of 220 Ω/□ for PEDOT/PSS conductive layer have been obtained. The experimental spring constant and the deflection sensitivity were measured to be 0.017 N/m and 8.59 × 10 -7 nm -1 , respectively. The biological sensing performances of polymeric micro-cantilever were investigated by the immunoassay for human immunoglobulin G (IgG). The immunosensor was experimentally demonstrated to have a linear behavior for the detection of IgG within the concentrations of 10~100 ng/mL with a limit of detection (LOD) of 10 ng/mL. The experimental results indicate that the proposed polymeric flexible conductive layer-based sensors are capable of detecting trace biological substances.

  12. Method for converting uranium oxides to uranium metal

    Science.gov (United States)

    Duerksen, Walter K.

    1988-01-01

    A process is described for converting scrap and waste uranium oxide to uranium metal. The uranium oxide is sequentially reduced with a suitable reducing agent to a mixture of uranium metal and oxide products. The uranium metal is then converted to uranium hydride and the uranium hydride-containing mixture is then cooled to a temperature less than -100.degree. C. in an inert liquid which renders the uranium hydride ferromagnetic. The uranium hydride is then magnetically separated from the cooled mixture. The separated uranium hydride is readily converted to uranium metal by heating in an inert atmosphere. This process is environmentally acceptable and eliminates the use of hydrogen fluoride as well as the explosive conditions encountered in the previously employed bomb-reduction processes utilized for converting uranium oxides to uranium metal.

  13. Uranium speciation in plants

    International Nuclear Information System (INIS)

    Guenther, A.; Bernhard, G.; Geipel, G.; Reich, T.; Rossberg, A.; Nitsche, H.

    2003-01-01

    Detailed knowledge of the nature of uranium complexes formed after the uptake by plants is an essential prerequisite to describe the migration behavior of uranium in the environment. This study focuses on the determination of uranium speciation after uptake of uranium by lupine plants. For the first time, time-resolved laser-induced fluorescence spectroscopy and X-ray absorption spectroscopy were used to determine the chemical speciation of uranium in plants. Differences were detected between the uranium speciation in the initial solution (hydroponic solution and pore water of soil) and inside the lupine plants. The oxidation state of uranium did not change and remained hexavalent after it was taken up by the lupine plants. The chemical speciation of uranium was identical in the roots, shoot axis, and leaves and was independent of the uranium speciation in the uptake solution. The results indicate that the uranium is predominantly bound as uranyl(VI) phosphate to the phosphoryl groups. Dandelions and lamb's lettuce showed uranium speciation identical to lupine plants. (orig.)

  14. 31 CFR 540.317 - Uranium feed; natural uranium feed.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Uranium feed; natural uranium feed... (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.317 Uranium feed; natural uranium feed. The...

  15. Signal-enhanced electrochemiluminescence immunosensor based on synergistic catalysis of nicotinamide adenine dinucleotide hydride and silver nanoparticles.

    Science.gov (United States)

    Wang, Guangjie; Jin, Feng; Dai, Nan; Zhong, Zhaoyang; Qing, Yi; Li, Mengxia; Yuan, Ruo; Wang, Dong

    2012-03-01

    A new metal-organic nanocomposite with synergistic catalysis function was prepared and developed to construct an electrochemiluminescence (ECL) immunosensor for ultrasensitive detection of tumor biomarker CA125. Silver nanoparticles (AgNPs) and nicotinamide adenine dinucleotide hydride (NADH) that can participate and catalyze the ECL reaction of Ru(bpy)(3)(2+) were employed as the metal component and the organic component to synthesize the metal-organic nanocomposite of NADH-AgNPs (NA). The novel ECL immunosensor was assembled via Ru(bpy)(3)(2+)-doped silica nanoparticles (Ru-SiO(2)) modified electrode with the NA as immune labels. First, the chitosan-suspended Ru-SiO(2) nanoparticles were cast on the gold electrode surface to immobilize the ECL probes of Ru(bpy)(3)(2+) and link gold nanoparticles. Then, the primary antibodies were loaded onto the modified electrode via the gold sulfhydryl covalent binding. After immunobinding the analytes of antigen, NA-attached secondary antibodies could be captured as a sandwich type on the electrode. Finally, based on the circularly synergistic catalysis by the silver and NADH for the solid-phase ECL of Ru(bpy)(3)(2+), the proposed immunosensor sensed the concentration of antigen. The synergistic ECL catalysis of metal-organic nanocomposite amplified response signal and pushed the detection limit down to 0.03 U ml(-1), which initiated a new ECL labeling field and has great significance for ECL immunoassays. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. Washing-free heterogeneous immunosensor using proximity-dependent electron mediation between an enzyme label and an electrode.

    Science.gov (United States)

    Dutta, Gorachand; Kim, Sinyoung; Park, Seonhwa; Yang, Haesik

    2014-05-06

    Washing processes, essential in most heterogeneous labeled assays, have been a big hurdle in simplifying the detection procedure and reducing assay time. Nevertheless, less attention has been paid to washing-free heterogeneous labeled assays. We report a purely washing-free immunosensor that allows fast, sensitive, and single-step detection of prostate-specific antigen in serum with low interference. Proximity-dependent electron mediation of ferrocenemethanol (Fc) between an indium-tin oxide (ITO) electrode and a glucose-oxidase (GOx) label allows us to discriminate between a bound and an unbound label: a bound label offers faster electron mediation than an unbound one. The electrooxidation of Fc at a low applied potential (0.13 V vs Ag/AgCl) and a low electrocatalytic ITO electrode and the oxidation of l-ascorbic acid by l-ascorbate oxidase minimize the effect of the interfering species. With a high concentration of glucose (200 mM), the signal and background levels are hardly dependent on the glucose-concentration variation in the sample. The washing-free immunosensor can detect a concentration of ca. 1 pg/mL for mouse IgG in phosphate-buffered saline and a concentration of ca. 10 pg/mL for prostate-specific antigen spiked in female serum after an incubation period of 10 min. The concentrations measured with actual clinical serum samples are in good agreement with the concentrations measured with a commercial instrument, which renders the washing-free heterogeneous immunosensor appealing for practical use.

  17. Quinone-Based Polymers for Label-Free and Reagentless Electrochemical Immunosensors: Application to Proteins, Antibodies and Pesticides Detection

    Directory of Open Access Journals (Sweden)

    Minh-Chau Pham

    2013-01-01

    Full Text Available Polyquinone derivatives are widely recognized in the literature for their remarkable properties, their biocompatibility, simple synthesis, and easy bio-functionalization. We have shown that polyquinones present very stable electroactivity in neutral aqueous medium within the cathodic potential domain avoiding side oxidation of interfering species. Besides, they can act as immobilized redox transducers for probing biomolecular interactions in sensors. Our group has been working on devices based on such modified electrodes with a view to applications for proteins, antibodies and organic pollutants using a reagentless label-free electrochemical immunosensor format. Herein, these developments are briefly reviewed and put into perspective.

  18. A regenerable piezoelectric immunosensor on the basis of electropolymerized polypyrrole for highly selective detection of Staphylococcal Enterotoxin A in foodstuffs

    International Nuclear Information System (INIS)

    Karaseva, Nadezhda; Ermolaeva, Tatyana

    2015-01-01

    Piezoelectric immunosensors have been developed for the determination of trace concentrations of Staphylococcal enterotoxin A (SEA) in foodstuff. Antibodies against SEA were covalently immobilized on an electropolymerized polypyrrole substrate on a gold electrode which warrants increased stability of the biolayer and sensitive detection. The calibration plot is linear in the 1–80 ng∙mL -1 SEA concentration range, the limit of detection is 0.4 ng∙mL -1 , and the time of analysis is <30 min. The sensor was successfully applied to quantify SEA in chicken meat and milk. (author)

  19. Uranium of Kazakhstan

    International Nuclear Information System (INIS)

    Tsalyuk, Yu.; Gurevich, D.

    2000-01-01

    Over 25 % of the world's uranium reserves are concentrated in Kazakhstan. So, the world's largest Shu-Sarysu uranium province is situated on southern Kazakhstan, with resources exceeding 1 billion tonnes of uranium. No less, than 3 unique deposits with resources exceeding 100,000 tonnes are situated here. From the economic point of view the most important thing is that these deposits are suitable for in-situ leaching, which is the cheapest, environmentally friendly and most efficient method available for uranium extracting. In 1997 the Kazatomprom National Joint-Stock Company united all Kazakhstan's uranium enterprises (3 mine and concentrating plants, Volkovgeologiya Joint-Stock Company and the Ulbinskij Metallurgical plant). In 1998 uranium production came to 1,500 tonnes (860 kg in 1997). In 1999 investment to the industry were about $ 30 million. Plans for development of Kazakhstan's uranium industry provide a significant role for foreign partners. At present, 2 large companies (Comeco (Canada), Cogema (France) working in Kazakhstan. Kazakatomprom continues to attract foreign investors. The company's administration announced that in that in next year they have plan to make a radical step: to sell 67 % of stocks to strategic investors (at present 100 % of stocks belongs to state). Authors of the article regard, that the Kazakhstan's uranium industry still has significant reserves to develop. Even if the scenario for the uranium industry could be unfavorable, uranium production in Kazakhstan may triple within the next three to four years. The processing of uranium by the Ulbinskij Metallurgical Plant and the production of some by-products, such as rhenium, vanadium and rare-earth elements, may provide more profits. Obviously, the sale of uranium (as well as of any other reserves) cannot make Kazakhstan a prosperous country. However, country's uranium industry has a god chance to become one of the most important and advanced sectors of national economy

  20. Amperometric immunosensor for {alpha}-fetoprotein antigen in human serum based on co-immobilizing dinuclear copper complex and gold nanoparticle doped chitosan film

    Energy Technology Data Exchange (ETDEWEB)

    Gan Ning; Meng Linghua; Wang Feng [State Key Laboratory Base of Novel Functional Materials and Preparation science, Faculty of Material Science and Chemical Engineering of Ninbo University, Ningbo, 315211 (China)], E-mail: ganning@nbu.edu.cn

    2009-09-01

    A sensitive amperometric immunosensor for {alpha}-fetoprotein (AFP), a tumor marker for the diagnosis of hepatocellular carcinoma (HCC), was constructed, The immunosensor is prepared by co-immobilizing [Cu{sub 2}(phen){sub 2}Cl{sub 2}] ({mu}-Cl){sub 2} (CuL), nano-Au/Chitosan(Chit) composite, horseradish peroxidase (HRP) and AFP antibody(anti-AFP) on a glassy carbon electrode (GCE). Firstly, CuL was irreversibly absorb on GCE electrode through {pi}-{pi} stacking interaction; then nano-Au/Chit composite was immobilized onto the electrode because of its excellent membrane-forming ability, finally HRP and anti-AFP was adsorbed onto the surface of the gold nanoparticles to construct GCE | CuL/nanoAu-chit/HRP/anti-AFP immunosensor. The preparation procedure of the electrode was characterized by electrochemical and spectroscopy method. The results showed that this immunosensor exhibited an excellent electrocatalytic response to the reduction of hydrogen peroxide (H{sub 2}O{sub 2}) without the aid of an electron mediator, offers a high-sensitivity (1710 nA {center_dot} ng{sup -1} {center_dot} ml{sup -1}) for the detection of AFP and has good correlation for detection of AFP in the range of 0.2 to 120.0 ng/ml with a detection limit of 0.05 ng/ml. The biosensor showed high selectivity as well as good stability and reproductivity.

  1. Large-scale synthesis of ultrathin Au-Pt nanowires assembled on thionine/graphene with high conductivity and sensitivity for electrochemical immunosensor

    International Nuclear Information System (INIS)

    Lu, Wenbo; Ge, Juan; Tao, Lin; Cao, Xiaowei; Dong, Jian; Qian, Weiping

    2014-01-01

    In this article, for the first time, a novel, label-free and inherent electroactive redox biosensor based on ultrathin Au-Pt nanowire-decorated thionine/reduced graphene oxide (AuPtNWs/THI/rGO) is developed for carcinoembryonic antigen (CEA) detection. Ultrathin AuPtNWs are prepared by a one-pot synthesis method without the use of any stabilizer or template. The AuPtNWs/THI/rGO composites are obtained by the THI/rGO composites surface functionalized with -NH 2 group employed as a support for loading ultrathin AuPtNWs by coordination. The AuPtNWs/THI/rGO composites not only favor the immobilization of antibody but also facilitate the electron transfer. It is found that the resultant AuPtNWs/THI/rGO composites can be designed to act as a sensitive label-free electrochemical immunosensor for CEA determination. Under the optimized conditions, the linear range of the proposed immunosensor is estimated to be from 50 fg·mL −1 to 100 ng·mL −1 (R= 0.998) and the detection limit is estimated to be 6 fg·mL −1 at a signal-to-noise ratio of 3, respectively. The prepared immunosensor for detection of CEA shows high sensitivity, reproducibility and stability. Our study demonstrates that the proposed immunosensor has also been used to determine CEA successfully in diluted blood samples

  2. Electrochemical impedance spectroscopy for analytical determination of paraquat in meconium samples using an immunosensor modified with fullerene, ferrocene and ionic liquid

    Energy Technology Data Exchange (ETDEWEB)

    Sun Xiulan [State Key Laboratory of Food Science and Technology, Wuxi 214122 (China); Li Zaijun, E-mail: zaijunli@263.ne [School of Chemical and Materials Engineering, Jiangnan University, Lihu Road 1800, Wuxi 214122 (China); Cai, Yan; Wei, Zhilei [School of Chemical and Materials Engineering, Jiangnan University, Lihu Road 1800, Wuxi 214122 (China); Fang Yinjun; Ren Guoxiao; Huang Yaru [Zhejiang Zanyu Technology Limited Corporation, Hangzhou 311215 (China)

    2011-01-01

    The paper reports a highly sensitive electrochemical immunosensor for the detection of paraquat. The immunosensor bases on glassy carbon electrode modified with a composite made from fullerene, ferrocene and the ionic liquid. The components were immobilized on the electrode surface by chitosan. The antibody of paraquat was covalently conjugated to the surface which was then blocked with bovine serum albumin. Analytical characteristics of the immunosensor were investigated by electrochemical impedance spectroscopy. It offers good repeatability (RSD = 1.5%), a stability of more than 150 days, an impedimetric response to paraquat in the range from 3.89 x 10{sup -11} to 4.0 x 10{sup -8} mol L{sup -1}, and a detection limit (S/N = 3) of 9.0 x 10{sup -12} mol L{sup -1}. The effects of omitting fullerene and the ionic liquid were well tested. The results indicated that sensitivity of the immunosensor is 3.7-fold better if fullerene and ionic liquid are used. This demonstrates that fullerene facilitates electron transfer on surface of the electrode due to unique electrochemical properties, while the ionic liquid provides biocompatible microenvironment for the antibody, which results in the enhanced sensitivity and stability. Moreover, surface morphology feature and electrochemical properties of the electrode were also examined. The method was satisfactorily applied to the determination of paraquat in meconium.

  3. Titrimetric determination of uranium

    International Nuclear Information System (INIS)

    Florence, T.M.

    1989-01-01

    Titrimetric methods are almost invariably used for the high precision assay of uranium compounds, because gravimetric methods are nonselective, and not as reliable. Although precipitation titrations have been used, for example with cupferron and ferrocyanide, and chelate titrations with EDTA and oxine give reasonable results, in practice only redox titrations find routine use. With all redox titration methods for uranium a precision of 01 to 02 percent can be achieved, and precisions as high as 0.003 percent have been claimed for the more refined techniques. There are two types of redox titrations for uranium in common use. The first involves the direct titration of uranium (VI) to uranium (IV) with a standard solution of a strong reductant, such as chromous chloride or titanous chloride, and the second requires a preliminary reduction of uranium to the (IV) or (III) state, followed by titration back to the (VI) state with a standard oxidant. Both types of redox titrations are discussed. 4 figs

  4. Politics of Uranium

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    Uranium is the most political of all the elements, the material for the production of both the large amounts of electricity and the most destructive weapons in the world. The problems that its dual potential creates are only now beginning to become evident. Author Norman Moss looks at this situation and sheds light on many of the questions that emerge. The nuclear issue always comes back to how much uranium there is, what can be done with it, and which countries have it. Starting with a concise history of uranium and explaining its technology in terms the nonspecialist can understand, The Politics of Uranium considers the political issues that technical arguments obscure. It tells the little-known story of the international uranium cartel, explains the entanglements of governments with the uranium trade, and describes the consequences of wrong decisions and blunders-especially the problems of nuclear waste. It also examines the intellectual and emotional roots of the anti-nuclear movement

  5. Uranium resources and supply

    International Nuclear Information System (INIS)

    Cameron, J.

    1973-01-01

    The future supply of uranium has to be considered against a background of forecasts of uranium demand over the next decades which show increases of a spectacular nature. It is not necessary to detail these forecasts, they are well known. A world survey by the Joint NEA/IAEA Working Party on 'Uranium Resources, Production and Demand', completed this summer, indicates that from a present production level of just over 19,000 tonnes uranium per year, the demand will rise to the equivalent of an annual production requirement of 50,000 tonnes uranium by 1980, 100,000 by 1985 and 180,000 by 1990. Few, if any, mineral production industries have been called upon to plan for a near tenfold increase in production in a space of about 15 years as these forecasts imply. This might possibly mean that, perhaps, ten times the present number of uranium mines will have to be planned and engineered by 1990

  6. How much uranium

    International Nuclear Information System (INIS)

    Kenward, M.

    1976-01-01

    Comment is made on the latest of a series of reports on world uranium resources from the OECD's Nuclear Energy Agency and the UN's International Atomic Energy Agency (Uranium resources, production and demand (including other nuclear fuel cycle data), published by the Organisation for Economic Cooperation and Development, Paris). The report categories uranium reserves by their recovery cost and looks at power demand and the whole of the nuclear fuel cycle, including uranium enrichment and spent fuel reprocessing. The effect that fluctuations in uranium prices have had on exploration for new uranium resources is considered. It is stated that increased exploration is essential considering the long lead times involved but that thanks to today's higher prices there are distinct signs that prospecting activities are increasing again. (U.K.)

  7. Uranium Mill Tailings Management

    International Nuclear Information System (INIS)

    Nelson, J.D.

    1982-01-01

    This book presents the papers given at the Fifth Symposium on Uranium Mill Tailings Management. Advances made with regard to uranium mill tailings management, environmental effects, regulations, and reclamation are reviewed. Topics considered include tailings management and design (e.g., the Uranium Mill Tailings Remedial Action Project, environmental standards for uranium mill tailings disposal), surface stabilization (e.g., the long-term stability of tailings, long-term rock durability), radiological aspects (e.g. the radioactive composition of airborne particulates), contaminant migration (e.g., chemical transport beneath a uranium mill tailings pile, the interaction of acidic leachate with soils), radon control and covers (e.g., radon emanation characteristics, designing surface covers for inactive uranium mill tailings), and seepage and liners (e.g., hydrologic observations, liner requirements)

  8. Geochemical exploration for uranium

    International Nuclear Information System (INIS)

    1988-01-01

    This Technical Report is designed mainly to introduce the methods and techniques of uranium geochemical exploration to exploration geologists who may not have had experience with geochemical exploration methods in their uranium programmes. The methods presented have been widely used in the uranium exploration industry for more than two decades. The intention has not been to produce an exhaustive, detailed manual, although detailed instructions are given for a field and laboratory data recording scheme and a satisfactory analytical method for the geochemical determination of uranium. Rather, the intention has been to introduce the concepts and methods of uranium exploration geochemistry in sufficient detail to guide the user in their effective use. Readers are advised to consult general references on geochemical exploration to increase their understanding of geochemical techniques for uranium

  9. Classification of Uranium deposits

    International Nuclear Information System (INIS)

    Dahlkamp, F.J.

    1978-01-01

    A listing of the recognized types of uranium mineralization shows nineteen determinable types out of which only six can be classified as of economic significance at present: Oligomiitic quartz pebble conglomerates, sandstone types, calcretes, intra-intrusive types, hydrothermal veins, veinlike types. The different types can be genetically related to prevalent geological environments, i.e. 1. the primary uranium occurrences formed by endogenic processes, 2. the secondary derived from the primary by subsequent exogenic processes, 3. the tertiary occurrences are assumed to be formed by endogenic metamorphic processes, although little is known about the behaviour of the uranium during the metamorphosis and therefore the metallogenesis of this tertiary uranium generation is still vague. A metallotectonic-geochronologic correlation of the uranium deposits shows a distinct affinity of the uranium to certain geological epochs: The Upper Archean, Lower Proterozoic, the Hercynian and, in a less established stage, the Upper Proterozoic. (orig.) 891 HP/orig. 892 MKO [de

  10. Uranium Newsletter. No. 1

    International Nuclear Information System (INIS)

    1987-03-01

    The new Uranium Newsletter is presented as an IAEA annual newsletter. The organization of the IAEA and its involvement with uranium since its founding in 1957 is described. The ''Red Book'' (Uranium Resources, Production and Demand) is mentioned. The Technical Assistance Programme of the IAEA in this field is also briefly mentioned. The contents also include information on the following meetings: The Technical Committee Meeting on Uranium Deposits in Magmatic and Metamorphic Rocks, Advisory Group Meeting on the Use of Airborne Radiometric Data, and the Technical Committee Meeting on Metallogenesis. Recent publications are listed. Current research contracts in uranium exploration are mentioned. IAEA publications on uranium (in press) are listed also. Country reports from the following countries are included: Australia, Brazil, Canada, China (People's Republic of), Denmark, Finland, Germany (Federal Republic of), Malaysia, Philippines, Portugal, South Africa (Republic of), Spain, Syrian Arab Republic, United Kingdom, United States of America, Zambia, and Greece. There is also a report from the Commission of European Communities

  11. Uranium purchases report 1992

    International Nuclear Information System (INIS)

    1993-01-01

    Data reported by domestic nuclear utility companies in their responses to the 1991 and 1992 ''Uranium Industry Annual Survey,'' Form EIA-858, Schedule B ''Uranium Marketing Activities,are provided in response to the requirements in the Energy Policy Act 1992. Data on utility uranium purchases and imports are shown on Table 1. Utility enrichment feed deliveries and secondary market acquisitions of uranium equivalent of US DOE separative work units are shown on Table 2. Appendix A contains a listing of firms that sold uranium to US utilities during 1992 under new domestic purchase contracts. Appendix B contains a similar listing of firms that sold uranium to US utilities during 1992 under new import purchase contracts. Appendix C contains an explanation of Form EIA-858 survey methodologies with emphasis on the processing of Schedule B data

  12. A dual amplified electrochemical immunosensor for ofloxacin: Polypyrrole film-Au nanocluster as the matrix and multi-enzyme-antibody functionalized gold nanorod as the label

    International Nuclear Information System (INIS)

    Zang, Shuai; Liu, Yingju; Lin, Mouhong; Kang, Jianli; Sun, Yuanming; Lei, Hongtao

    2013-01-01

    Graphical abstract: Schematic representation of the OFL electrochemical immunosensor using Au nanoclusters/PPy/GCE as the substrate and multi-HRP-GNR-Ab2 bioconjugates as the label. Highlights: ► Gold nanorod was used to load HRP and Ab 2 to form multi-HRP-GNR-Ab 2 . ► A sensitive immunosensor for ofloxacin was constructed using the homemade antibody. ► A dual signal amplified strategy was based on the PPy-Au and multi-HRP-GNR-Ab 2 . -- Abstract: In this work, an electrochemical immunosensor, basing on a dual signal amplified strategy by employing a biocompatible polypyrrole film-Au nanocluster matrix as a sensor platform and multi-enzyme-antibody functionalized gold nanorod as an electrochemical detection label, is established for sensitive detection of ofloxacin (OFL). Firstly, polypyrrole film and Au nanoclusters were progressively fabricated onto the surface of a glassy carbon electrode via electropolymerization and electrochemical deposition, respectively. Such PPy-Au nanocomposite modified electrode was used to immobilize OFL-OVA, blocked with the blocking reagent, and then associated with the corresponding antibody. Secondly, gold nanorod (GNR) was synthesized to load horseradish peroxidase (HRP) and horseradish peroxidase-secondary antibody (HRP-Ab 2 ), and the resulting nanostructure (multi-HRP-GNR-Ab 2 ) was applied as the detection label. The fabrication process of the ordered multilayer structure and immunosensor were characterized by scanning electron microscopy (SEM) and electrochemical measurements, respectively. Finally, based on a competitive immunoassay, i.e., the association ability with the corresponding antibody between the captured antigen and free OFL in the solution, the fabricated immunosensor exhibited a sensitive response to OFL in the range from 0.08 to 410 ng/mL with a detection limit of 0.03 ng/mL. The current immunosensor exhibited good sensitivity, selectivity and long-term stability. This amplification strategy shows excellent

  13. Process for continuous production of metallic uranium and uranium alloys

    Science.gov (United States)

    Hayden, Jr., Howard W.; Horton, James A.; Elliott, Guy R. B.

    1995-01-01

    A method is described for forming metallic uranium, or a uranium alloy, from uranium oxide in a manner which substantially eliminates the formation of uranium-containing wastes. A source of uranium dioxide is first provided, for example, by reducing uranium trioxide (UO.sub.3), or any other substantially stable uranium oxide, to form the uranium dioxide (UO.sub.2). This uranium dioxide is then chlorinated to form uranium tetrachloride (UCl.sub.4), and the uranium tetrachloride is then reduced to metallic uranium by reacting the uranium chloride with a metal which will form the chloride of the metal. This last step may be carried out in the presence of another metal capable of forming one or more alloys with metallic uranium to thereby lower the melting point of the reduced uranium product. The metal chloride formed during the uranium tetrachloride reduction step may then be reduced in an electrolysis cell to recover and recycle the metal back to the uranium tetrachloride reduction operation and the chlorine gas back to the uranium dioxide chlorination operation.

  14. Process for continuous production of metallic uranium and uranium alloys

    Science.gov (United States)

    Hayden, H.W. Jr.; Horton, J.A.; Elliott, G.R.B.

    1995-06-06

    A method is described for forming metallic uranium, or a uranium alloy, from uranium oxide in a manner which substantially eliminates the formation of uranium-containing wastes. A source of uranium dioxide is first provided, for example, by reducing uranium trioxide (UO{sub 3}), or any other substantially stable uranium oxide, to form the uranium dioxide (UO{sub 2}). This uranium dioxide is then chlorinated to form uranium tetrachloride (UCl{sub 4}), and the uranium tetrachloride is then reduced to metallic uranium by reacting the uranium chloride with a metal which will form the chloride of the metal. This last step may be carried out in the presence of another metal capable of forming one or more alloys with metallic uranium to thereby lower the melting point of the reduced uranium product. The metal chloride formed during the uranium tetrachloride reduction step may then be reduced in an electrolysis cell to recover and recycle the metal back to the uranium tetrachloride reduction operation and the chlorine gas back to the uranium dioxide chlorination operation. 4 figs.

  15. New french uranium mineral species

    International Nuclear Information System (INIS)

    Branche, G.; Chervet, J.; Guillemin, C.

    1952-01-01

    In this work, the authors study the french new uranium minerals: parsonsite and renardite, hydrated phosphates of lead and uranium; kasolite: silicate hydrated of uranium and lead uranopilite: sulphate of uranium hydrated; bayleyite: carbonate of uranium and of hydrated magnesium; β uranolite: silicate of uranium and of calcium hydrated. For all these minerals, the authors give the crystallographic, optic characters, and the quantitative chemical analyses. On the other hand, the following species, very rare in the french lodgings, didn't permit to do quantitative analyses. These are: the lanthinite: hydrated uranate oxide; the α uranotile: silicate of uranium and of calcium hydrated; the bassetite: uranium phosphate and of hydrated iron; the hosphuranylite: hydrated uranium phosphate; the becquerelite: hydrated uranium oxide; the curite: oxide of uranium and lead hydrated. Finally, the authors present at the end of this survey a primary mineral: the brannerite, complex of uranium titanate. (author) [fr

  16. Uranium demand. An exploration challenge

    Energy Technology Data Exchange (ETDEWEB)

    Roux, A J.A.

    1976-10-01

    The estimated world resources of uranium as well as the estimated consumption of uranium over the next 25 years are briefly discussed. Attention is also given to the prospecting for uranium in South Africa and elsewhere in the world.

  17. Lichens as biomonitors of uranium in the Balkan area

    Energy Technology Data Exchange (ETDEWEB)

    Loppi, S.; Riccobono, F.; Zhang, Z.H.; Savic, S.; Ivanov, D.; Pirintsos, S.A

    2003-09-01

    Widespread contamination by depleted uranium was not detected in the Balkan area. - The contribution of the conflict of 1999 to the environmental levels of uranium in the Balkan area was evaluated by means of lichens used as biomonitors. The average U concentration found in lichens in the present study was in line with the values reported for lichens from other countries and well below the levels found in lichens collected in areas with natural or anthropogenic sources of U. Measurement of isotopic ratios {sup 235}U/{sup 238}U allowed to exclude the presence of depleted uranium. According to these results, we could not detect widespread environmental contamination by depleted uranium in the Balkan area.

  18. Uranium industry annual, 1988

    International Nuclear Information System (INIS)

    1989-01-01

    This report presents data on US uranium raw materials and marketing activities of the domestic uranium industry. It contains aggregated data reported by US companies on the ''Uranium Industry Annual Survey'' (1988), Form EIA-858, and historical data from prior data collections and other pertinent sources. The report was prepared by the Energy Information Administration (EIA), the independent agency for data collection and analysis with the US Department of Energy

  19. Gold and uranium extraction

    International Nuclear Information System (INIS)

    James, G.S.; Davidson, R.J.

    1977-01-01

    A process for extracting gold and uranium from an ore containing them both comprising the steps of pulping the finely comminuted ore with a suitable cyanide solution at an alkaline pH, acidifying the pulp for uranium dissolution, adding carbon activated for gold recovery to the pulp at a suitable stage, separating the loaded activated carbon from the pulp, and recovering gold from the activated carbon and uranium from solution

  20. Uranium mine ventilation

    International Nuclear Information System (INIS)

    Katam, K.; Sudarsono

    1982-01-01

    Uranium mine ventilation system aimed basically to control and decreasing the air radioactivity in mine caused by the radon emanating from uranium ore. The control and decreasing the air ''age'' in mine, with adding the air consumption volume, increasing the air rate consumption, closing the mine-out area; using closed drainage system. Air consumption should be 60m 3 /minute for each 9m 2 uranium ore surfaces with ventilation rate of 15m/minute. (author)

  1. Pine Creek uranium province

    International Nuclear Information System (INIS)

    Bower, M.B.; Needham, R.S.; Page, R.W.; Stuart-Smith, P.G.; Wyborn, L.A.I.

    1985-01-01

    The objective of this project is to help establish a sound geological framework of the Pine Creek region through regional geological, geochemical and geophysical studies. Uranium ore at the Coronation Hill U-Au mine is confined to a wedge of conglomerate in faulted contact with altered volcanics. The uranium, which is classified as epigenetic sandstone type, is derived from a uranium-enriched felsic volcanic source

  2. Chemical thermodynamics of uranium

    International Nuclear Information System (INIS)

    Grenthe, I.; Fuger, J.; Lemire, R.J.; Muller, A.B.; Nguyen-Trung Cregu, C.; Wanner, H.

    1992-01-01

    A comprehensive overview on the chemical thermodynamics of those elements that are of particular importance in the safety assessment of radioactive waste disposal systems is provided. This is the first volume in a series of critical reviews to be published on this subject. The book provides an extensive compilation of chemical thermodynamic data for uranium. A description of procedures for activity corrections and uncertainty estimates is given. A critical discussion of data needed for nuclear waste management assessments, including areas where significant gaps of knowledge exist is presented. A detailed inventory of chemical thermodynamic data for inorganic compounds and complexes of uranium is listed. Data and their uncertainty limits are recommended for 74 aqueous complexes and 199 solid and 31 gaseous compounds containing uranium, and on 52 aqueous and 17 solid auxiliary species containing no uranium. The data are internally consistent and compatible with the CODATA Key Values. The book contains a detailed discussion of procedures used for activity factor corrections in aqueous solution, as well as including methods for making uncertainty estimates. The recommended data have been prepared for use in environmental geochemistry. Containing contributions written by experts the chapters cover various subject areas such a s: oxide and hydroxide compounds and complexes, the uranium nitrides, the solid uranium nitrates and the arsenic-containing uranium compounds, uranates, procedures for consistent estimation of entropies, gaseous and solid uranium halides, gaseous uranium oxides, solid phosphorous-containing uranium compounds, alkali metal uranates, uncertainties, standards and conventions, aqueous complexes, uranium minerals dealing with solubility products and ionic strength corrections. The book is intended for nuclear research establishments and consulting firms dealing with uranium mining and nuclear waste disposal, as well as academic and research institutes

  3. Uranium in Canada

    International Nuclear Information System (INIS)

    1985-09-01

    In 1974 the Minister of Energy, Mines and Resources (EMR) established a Uranium Resource Appraisal Group (URAG) within EMR to audit annually Canada's uranium resources for the purpose of implementing the federal government's uranium export policy. A major objective of this policy was to ensure that Canadian uranium supplies would be sufficient to meet the needs of Canada's nuclear power program. As projections of installed nuclear power growth in Canada over the long term have been successively revised downwards (the concern about domestic security of supply is less relevant now than it was 10 years ago) and as Canadian uranium supply capabilities have expanded significantly. Canada has maintained its status as the western world's leading exporter of uranium and has become the world's leading producer. Domestic uranium resource estimates have increased to 551 000 tonnes U recoverable from mineable ore since URAG completed its last formal assessment (1982). In 1984, Canada's five primary uranium producers employed some 5800 people at their mining and milling operations, and produced concentrates containing some 11 170 tU. It is evident from URAG's 1984 assessment that Canada's known uranium resources, recoverable at uranium prices of $150/kg U or less, are more than sufficient to meet the 30-year fuelling requirements of those reactors that are either in opertaion now or committed or expected to be in-service by 1995. A substantial portion of Canada's identified uranium resources, recoverable within the same price range, is thus surplus to Canadian needs and available for export. Sales worth close to $1 billion annually are assured. Uranium exploration expenditures in Canada in 1983 and 1984 were an estimated $41 million and $35 million, respectively, down markedly from the $128 million reported for 1980. Exploration drilling and surface development drilling in 1983 and 1984 were reported to be 153 000 m and 197 000 m, respectively, some 85% of which was in

  4. Disposable Electrochemical Immunosensor Diagnosis Device Based on Nanoparticle Probe and Immunochromatographic Strip

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Guodong; Lin, Ying-Ying; Wang, Jun; Wu, Hong; Wai, Chien M.; Lin, Yuehe

    2007-10-15

    We describe a disposable electrochemical immunosensor diagnosis device that is based on the immunochromatographic strip technique and an electrochemical immunoassay based on quantum dot (QD, CdS@ZnS) labels. The device takes advantage of the speed and low-cost of the conventional immunochromatographic strip test and the high-sensitivity of the nanoparticle-based electrochemical immunoassay. A sandwich immunoreaction was performed on the immunochromatographic strip, and the captured QD labels in the test zone were determined by highly sensitive stripping voltammetric measurement of the dissolved metallic component (cadmium) with a disposable-screen-printed electrode, which is embedded underneath the membrane on the test zone. The new device coupled with a portable electrochemical analyzer shows great promise for in-field and point-of-care quantitative testing of disease-related protein biomarkers. The parameters (e.g., voltammetric measurement of QD labels, antibody immobilization, the loading amount of QD-antibody, and the immunoreaction time) that govern the sensitivity and reproducibility of the device were optimized with IgG model analyte. The voltammetric response of the optimized device is highly linear over the range of 0.1 to 10 ng mL-1 IgG, and the limit of detection is estimated to be 30 pg mL-1 in association with a 7-min immunoreaction time. The detection limit was improved to 10 pg mL-1 using a 20-min immunoreaction time. The new disposable electrochemical diagnosis device thus provides a more user-friendly, rapid, clinically accurate, less expensive, and quantitative tool for protein detection.

  5. An Amperometric Immunosensor Based on Multi-Walled Carbon Nanotubes-Thionine-Chitosan Nanocomposite Film for Chlorpyrifos Detection

    Science.gov (United States)

    Sun, Xia; Cao, Yaoyao; Gong, Zhili; Wang, Xiangyou; Zhang, Yan; Gao, Jinmei

    2012-01-01

    In this work, a novel amperometric immunosensor based on multi-walled carbon nanotubes-thionine-chitosan (MWCNTs-THI-CHIT) nanocomposite film as electrode modified material was developed for the detection of chlorpyrifos residues. The nanocomposite film was dropped onto a glassy carbon electrode (GCE), and then the anti-chlorpyrifos monoclonal antibody was covalently immobilized onto the surface of MWCNTs-THI-CHIT/GCE using the crosslinking agent glutaraldehyde (GA). The modification procedure was characterized by using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under the optimized conditions, a linear relationship between the relative change in peak current of different pulse voltammetry (DPV) and the logarithm of chlorpyrifos solution concentration was obtained in the range from 0.1 to 1.0 × 105 ng/mL with a detection limit of 0.046 ng/mL. The proposed chlorpyrifos immunosensor exhibited high reproducibility, stability, and good selectivity and regeneration, making it a potential alternative tool for ultrasensitive detection of chlorpyrifos residues in vegetables and fruits. PMID:23443396

  6. Improvement of Accuracy in Flow Immunosensor System by Introduction of Poly-2-[3-(methacryloylaminopropylammonio]ethyl 3-aminopropyl Phosphate

    Directory of Open Access Journals (Sweden)

    Yusuke Fuchiwaki

    2011-01-01

    Full Text Available In order to improve the accuracy of immunosensor systems, poly-2-[3-(methacryloylaminopropylammonio]ethyl 3-aminopropyl phosphate (poly-3MAm3AP, which includes both phosphorylcholine and amino groups, was synthesized and applied to the preparation of antibody-immobilized beads. Acting as an antibody-immobilizing material, poly-3MAm3AP is expected to significantly lower nonspecific adsorption due to the presence of the phosphorylcholine group and recognize large numbers of analytes due to the increase in antibody-immobilizing sites. The elimination of nonspecific adsorption was compared between the formation of a blocking layer on antibody-immobilized beads and the introduction of a material to combine antibody with beads. Determination with specific and nonspecific antibodies was then investigated for the estimation of signal-to-noise ratio. Signal intensities with superior signal-to-noise ratios were obtained when poly-3MAm3AP was introduced. This may be due to the increase in antibody-immobilizing sites and the extended space for antigen-antibody interaction resulting from the electrostatic repulsion of poly-3MAm3AP. Thus, the application of poly-3MAm3AP coatings to immunoassay beads was able to improve the accuracy of flow immunosensor systems.

  7. Facile synthesis of cuprous oxide nanowires decorated graphene oxide nanosheets nanocomposites and its application in label-free electrochemical immunosensor.

    Science.gov (United States)

    Wang, Huan; Zhang, Yong; Wang, Yulan; Ma, Hongmin; Du, Bin; Wei, Qin

    2017-01-15

    In this work, the assembly between one-dimensional (1D) nanomaterials and two-dimensional (2D) nanomaterials was achieved by a simple method. Cuprous oxide nanowires decorated graphene oxide nanosheets (Cu 2 O@GO) nanocomposites were synthesized for the first time by a simple electrostatic self-assembly process. The nanostructure was well confirmed by scanning electron microscope (SEM) and transmission electron microscope (TEM) images. Taking advantages of good electrocatalytic activity and high specific surface area of Cu 2 O@GO nanocomposites, a label-free electrochemical immunosensor was developed by employing Cu 2 O@GO as signal amplification platform for the quantitative detection of alpha fetoprotein (AFP). In addition, toluidine blue (TB) was used as the electron transfer mediator to provide the electrochemical signal, which was adsorbed on graphene oxide nanosheets (GO NSs) by electrostatic attraction. The detection mechanism was based on the monitoring of the electrochemical current response change of TB by the square wave voltammetry (SWV) when immunoreaction occurred on the surface of electrode. Under optimal conditions, the proposed immunosensor displayed a high sensitivity and a low detection limit. This designed method may provide an effective method in the clinical diagnosis of AFP and other tumor markers. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Towards the use of protein A-tagged gold nanoparticles for signal amplification of electrochemical immunosensors in virus detection

    International Nuclear Information System (INIS)

    Huy Tran, Quang; Thuy Nguyen, Thanh; Chung Pham, Van; Hong Hanh Nguyen, Thi; Tuan Mai, Anh

    2012-01-01

    In this paper we represent a study on the potential use of protein A-tagged gold nanoparticles applied for signal amplification of electrochemical immunosensors. Gold nanoparticles (GNPs) were synthesized by the chemical reduction of tetrachloroauric (III) acid trihydrate using sodium ascorbate, and then tagged with protein A (PrA) via ultracentrifugation. UV-Vis spectroscopy and transmission electron microscopy were used to verify the characteristics of formed GNPs/PrA complex. The analyzed results indicate that GNPs were found spherically, homogeneously, and with an average diameter of about 10 nm. Immunoelectron microscopy was then used to investigate the bioactivity of the GNPs/PrA complex in solution by the effective binding of GNPs to viral particles. Scanning electron and fluorescence microscopies were also used to investigate the distribution and the bioactivity of the GNPs/PrA complex on the surface of the interdigitated sensor. Consequently, this study provided some assumptions of the potential application of protein A-tagged gold nanoparticles for signal amplification of electrochemical immunosensors in virus detection from clinical samples

  9. Sensitivity Analysis of Different Shapes of a Plastic Optical Fiber-Based Immunosensor for Escherichia coli: Simulation and Experimental Results

    Directory of Open Access Journals (Sweden)

    Domingos M. C. Rodrigues

    2017-12-01

    Full Text Available Conventional pathogen detection methods require trained personnel, specialized laboratories and can take days to provide a result. Thus, portable biosensors with rapid detection response are vital for the current needs for in-loco quality assays. In this work the authors analyze the characteristics of an immunosensor based on the evanescent field in plastic optical fibers with macro curvature by comparing experimental with simulated results. The work studies different shapes of evanescent-wave based fiber optic sensors, adopting a computational modeling to evaluate the probes with the best sensitivity. The simulation showed that for a U-Shaped sensor, the best results can be achieved with a sensor of 980 µm diameter by 5.0 mm in curvature for refractive index sensing, whereas the meander-shaped sensor with 250 μm in diameter with radius of curvature of 1.5 mm, showed better sensitivity for either bacteria and refractive index (RI sensing. Then, an immunosensor was developed, firstly to measure refractive index and after that, functionalized to detect Escherichia coli. Based on the results with the simulation, we conducted studies with a real sensor for RI measurements and for Escherichia coli detection aiming to establish the best diameter and curvature radius in order to obtain an optimized sensor. On comparing the experimental results with predictions made from the modelling, good agreements were obtained. The simulations performed allowed the evaluation of new geometric configurations of biosensors that can be easily constructed and that promise improved sensitivity.

  10. An ultrasensitive sandwich type electrochemiluminescence immunosensor for triiodothyronine detection using silver nanoparticle-decorated graphene oxide as a nanocarrier.

    Science.gov (United States)

    Chou, Hung-Tao; Fu, Chien-Yu; Lee, Chi-Young; Tai, Nyan-Hwa; Chang, Hwan-You

    2015-09-15

    An ultrasensitive electrochemiluminescence (ECL) immunosensor was constructed to detect 3,3',5-triiodothyronine (T3). The system employed T3-conjugated, silver nanoparticle-decorated carboxylic graphene oxide (Ag@fGO-T3) as a carrier and anti-T3 antibody-tris(2,2'-bipyridyl) ruthenium(II) (Ru(bpy)3(2+)) as a probe. The Ag@fGO-T3 and Ru(bpy)3(2+) complex could be mobilized rapidly to the anode in the reaction chamber through electrophoresis. The fGO is reduced electrochemically at the electrode, and the electrons could transfer from an anode to the Ru(bpy)3(2+). The complex is excited at the electrode and an ECL signal is produced upon reacting with tripropylamine (TPrA). Because of its large surface area and excellent conductivity, Ag@fGO could enhance ECL signal significantly in the system. Quantitative measurement of T3 could be achieved in the range from 0.1 pg/mL to 0.8 ng/mL with a detection limit of 0.05 pg/mL. In addition, the novel immunosensor showed good specificity in the presence of serum, indicating its high potential in clinical use. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Sensitivity Analysis of Different Shapes of a Plastic Optical Fiber-Based Immunosensor for Escherichia coli: Simulation and Experimental Results.

    Science.gov (United States)

    Rodrigues, Domingos M C; Lopes, Rafaela N; Franco, Marcos A R; Werneck, Marcelo M; Allil, Regina C S B

    2017-12-19

    Conventional pathogen detection methods require trained personnel, specialized laboratories and can take days to provide a result. Thus, portable biosensors with rapid detection response are vital for the current needs for in-loco quality assays. In this work the authors analyze the characteristics of an immunosensor based on the evanescent field in plastic optical fibers with macro curvature by comparing experimental with simulated results. The work studies different shapes of evanescent-wave based fiber optic sensors, adopting a computational modeling to evaluate the probes with the best sensitivity. The simulation showed that for a U-Shaped sensor, the best results can be achieved with a sensor of 980 µm diameter by 5.0 mm in curvature for refractive index sensing, whereas the meander-shaped sensor with 250 μm in diameter with radius of curvature of 1.5 mm, showed better sensitivity for either bacteria and refractive index (RI) sensing. Then, an immunosensor was developed, firstly to measure refractive index and after that, functionalized to detect Escherichia coli . Based on the results with the simulation, we conducted studies with a real sensor for RI measurements and for Escherichia coli detection aiming to establish the best diameter and curvature radius in order to obtain an optimized sensor. On comparing the experimental results with predictions made from the modelling, good agreements were obtained. The simulations performed allowed the evaluation of new geometric configurations of biosensors that can be easily constructed and that promise improved sensitivity.

  12. An Elegant Analysis of White Spot Syndrome Virus Using a Graphene Oxide/Methylene Blue based Electrochemical Immunosensor Platform

    Science.gov (United States)

    Natarajan, Anusha; Devi, K. S. Shalini; Raja, Sudhakaran; Senthil Kumar, Annamalai

    2017-04-01

    White spot syndrome virus (WSSV) is a major devastating virus in aquaculture industry. A sensitive and selective diagnostic method for WSSV is a pressing need for the early detection and protection of the aquaculture farms. Herein, we first report, a simple electrochemical immunosensor based on methylene blue dye (MB) immobilized graphene oxide modified glassy carbon electrode (GCE/GO@MB) for selective, quick (35 ± 5 mins) and raw sample analysis of WSSV. The immunosensor was prepared by sequential modification of primary antibody, blocking agent (bovine serum album), antigen (as vp28 protein), secondary antibody coupled with horseradish peroxidase (Ab2-HRP) on the GCE/GO@MB. The modified electrode showed a well-defined redox peak at an equilibrium potential (E1/2), -0.4 V vs Ag/AgCl and mediated H2O2 reduction reaction without any false positive result and dissolved oxygen interferences in pH 7 phosphate buffer solution. Under an optimal condition, constructed calibration plot was linear in a range of 1.36 × 10-3 to 1.36 × 107 copies μL-1 of vp28. It is about four orders higher sensitive than that of the values observed with polymerase chain reaction (PCR) and western blot based WSSV detection techniques. Direct electrochemical immunosensing of WSSV in raw tissue samples were successfully demonstrated as a real sample system.

  13. Uranium production from phosphates

    International Nuclear Information System (INIS)

    Ketzinel, Z.; Folkman, Y.

    1979-05-01

    According to estimates of the world's uranium consumption, exploitation of most rich sources is expected by the 1980's. Forecasts show that the rate of uranium consumption will increase towards the end of the century. It is therefore desirable to exploit poor sources not yet in use. In the near future, the most reasonable source for developing uranium is phosphate rock. Uranium reserves in phosphates are estimated at a few million tons. Production of uranium from phosphates is as a by-product of phosphate rock processing and phosphoric acid production; it will then be possible to save the costs incurred in crushing and dissolving the rock when calculating uranium production costs. Estimates show that the U.S. wastes about 3,000 tons of uranium per annum in phosphoric acid based fertilisers. Studies have also been carried out in France, Yugoslavia and India. In Israel, during the 1950's, a small plant was operated in Haifa by 'Chemical and Phosphates'. Uranium processes have also been developed by linking with the extraction processes at Arad. Currently there is almost no activity on this subject because there are no large phosphoric acid plants which would enable production to take place on a reasonable scale. Discussions are taking place about the installation of a plant for phosphoric acid production utilising the 'wet process', producing 200 to 250,000 tons P 2 O 5 per annum. It is necessary to combine these facilities with uranium production plant. (author)

  14. Phospholyl-uranium complexes

    International Nuclear Information System (INIS)

    Gradoz, Philippe

    1993-01-01

    After having reported a bibliographical study on penta-methylcyclopentadienyl uranium complexes, and a description of the synthesis and radioactivity of uranium (III) and (IV) boron hydrides compounds, this research thesis reports the study of mono and bis-tetramethyl-phospholyl uranium complexes comprising chloride, boron hydride, alkyl and alkoxide ligands. The third part reports the comparison of structures, stabilities and reactions of homologue complexes in penta-methylcyclopentadienyl and tetramethyl-phospholyl series. The last part addresses the synthesis of tris-phospholyl uranium (III) and (IV) complexes. [fr

  15. International trade in uranium

    International Nuclear Information System (INIS)

    Two reports are presented; one has been prepared by the Uranium Institute and is submitted by the United Kingdom delegation, the other by the United States delegation. The report of the Uranium Institute deals with the influence of the government on international trade in uranium. This influence becomes apparent predominantly by export and import restrictions, as well as by price controls. The contribution submitted by the United States is a uranium market trend analysis, with pricing methods and contracting modes as well as the effect of government policies being investigated in the light of recent developments

  16. Uranium concentration in fossils

    International Nuclear Information System (INIS)

    Okano, J.; Uyeda, C.

    1988-01-01

    Recently it is known that fossil bones tend to accumulate uranium. The uranium concentration, C u in fossils has been measured so far by γ ray spectroscopy or by fission track method. The authors applied secondary ion mass spectrometry, SIMS, to detect the uranium in fossil samples. The purpose of this work is to investigate the possibility of semi-quantitative analyses of uranium in fossils, and to study the correlation between C u and the age of fossil bones. The further purpose of this work is to apply SIMS to measure the distribution of C u in fossil teeth

  17. METHOD OF ROLLING URANIUM

    Science.gov (United States)

    Smith, C.S.

    1959-08-01

    A method is described for rolling uranium metal at relatively low temperatures and under non-oxidizing conditions. The method involves the steps of heating the uranium to 200 deg C in an oil bath, withdrawing the uranium and permitting the oil to drain so that only a thin protective coating remains and rolling the oil coated uranium at a temperature of 200 deg C to give about a 15% reduction in thickness at each pass. The operation may be repeated to accomplish about a 90% reduction without edge cracking, checking or any appreciable increase in brittleness.

  18. A novel photoelectrochemical immunosensor by integration of nanobody and TiO2 nanotubes for sensitive detection of serum cystatin C

    International Nuclear Information System (INIS)

    Mi, Li; Wang, Pingyan; Yan, Junrong; Qian, Jing; Lu, Jusheng; Yu, Jiachao; Wang, Yuzhen; Liu, Hong; Zhu, Min; Wan, Yakun; Liu, Songqin

    2016-01-01

    Cystatin C (CysC) is a sensitive marker for the estimation of the glomerular filtration rate and the clinical diagnosis of different diseases. In this paper, CysC-specific nanobodies (Nbs) were isolated from a phage display nanobody library. A simple and sensitive photoelectrochemical immunosensor based on TiO 2 nanotube arrays (TNAs) was proposed for the sensitive detection of CysC. The TiO 2 nanotube arrays deposited by electrochemical anodization displayed a high and stable photocurrent response under irradiation. After coupling CysC-specific nanobody to TNA (Nb/TNA), the proposed immunosensor for CysC can be utilized for tracking the photocurrent change of Nb/TNA caused by immunoreactions between CysC and the immobilized CysC-specific Nb. This allowed for the determination of CysC with a calibration range from 0.72 pM to 7.19 nM. The variation of the photocurrent was in a linear relationship with the logarithm of the CysC concentration in the range of 0.72 pM–3.6 nM. The immunosensor had a correlation coefficient of 0.97 and a detection limit of 0.14 pM at a signal-to-noise ratio of 3. The proposed immunosensor showed satisfactory intra- and inter-assay accuracy, high selectivity and good stability. As a result, this proposed strategy would offer a novel and simple approach for the detection of immunoreactions, provide new insights in popularizing the diagnosis of CysC, and extend the application of TiO 2 nanotubes. - Highlights: • CysC-specific nanobody to CysC is isolated from phage display nanobody library. • A photoelectrochemical immunosensor for CysC develops by Nb modified TNA. • An excellent sensitivity and good selectivity of CysC sensing was obtained.

  19. A novel photoelectrochemical immunosensor by integration of nanobody and TiO{sub 2} nanotubes for sensitive detection of serum cystatin C

    Energy Technology Data Exchange (ETDEWEB)

    Mi, Li [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); Wang, Pingyan; Yan, Junrong [Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203 (China); Qian, Jing; Lu, Jusheng; Yu, Jiachao [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); Wang, Yuzhen; Liu, Hong [Plexera LLC, WA 98072 (United States); Zhu, Min [Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203 (China); Wan, Yakun, E-mail: ywansystemsbiology@gmail.com [Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203 (China); Jiangsu Nanobody Engineering and Research Center, Nantong 226010 (China); Liu, Songqin, E-mail: liusq@seu.edu.cn [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China)

    2016-01-01

    Cystatin C (CysC) is a sensitive marker for the estimation of the glomerular filtration rate and the clinical diagnosis of different diseases. In this paper, CysC-specific nanobodies (Nbs) were isolated from a phage display nanobody library. A simple and sensitive photoelectrochemical immunosensor based on TiO{sub 2} nanotube arrays (TNAs) was proposed for the sensitive detection of CysC. The TiO{sub 2} nanotube arrays deposited by electrochemical anodization displayed a high and stable photocurrent response under irradiation. After coupling CysC-specific nanobody to TNA (Nb/TNA), the proposed immunosensor for CysC can be utilized for tracking the photocurrent change of Nb/TNA caused by immunoreactions between CysC and the immobilized CysC-specific Nb. This allowed for the determination of CysC with a calibration range from 0.72 pM to 7.19 nM. The variation of the photocurrent was in a linear relationship with the logarithm of the CysC concentration in the range of 0.72 pM–3.6 nM. The immunosensor had a correlation coefficient of 0.97 and a detection limit of 0.14 pM at a signal-to-noise ratio of 3. The proposed immunosensor showed satisfactory intra- and inter-assay accuracy, high selectivity and good stability. As a result, this proposed strategy would offer a novel and simple approach for the detection of immunoreactions, provide new insights in popularizing the diagnosis of CysC, and extend the application of TiO{sub 2} nanotubes. - Highlights: • CysC-specific nanobody to CysC is isolated from phage display nanobody library. • A photoelectrochemical immunosensor for CysC develops by Nb modified TNA. • An excellent sensitivity and good selectivity of CysC sensing was obtained.

  20. Core–shell Fe3O4–Au magnetic nanoparticles based nonenzymatic ultrasensitive electrochemiluminescence immunosensor using quantum dots functionalized graphene sheet as labels

    International Nuclear Information System (INIS)

    Liu, Weiyan; Zhang, Yan; Ge, Shenguang; Song, Xianrang; Huang, Jiadong; Yan, Mei; Yu, Jinghua

    2013-01-01

    Graphical abstract: Core–shell Fe 3 O 4 –Au magnetic nanoparticles and P-GS@QDs were prepared to immobilize Ab 1 and Ab 2 respectively and combined to fabricate a novel sandwich-type ECL immunosensor for detecting CA125 at low concentration. Highlights: ► ECL immunosensor for CA125 based on a microfluidic strategy with a homemade ECL cell was proposed. ► Core–shell Fe 3 O 4 –Au magnetic nanoparticles were employed as the carriers of the primary antibodies. ► CdTe quantum dots functionalized graphene sheet were used for signal amplification. -- Abstract: In this paper, a novel, low-cost electrochemiluminescence (ECL) immunosensor using core–shell Fe 3 O 4 –Au magnetic nanoparticles (AuMNPs) as the carriers of the primary antibody of carbohydrate antigen 125 (CA125) was designed. Graphene sheet (GS) with property of good conductivity and large surface area was a captivating candidate to amplify ECL signal. We successively synthesized functionalized GS by loading large amounts of quantum dots (QDs) onto the poly (diallyldimethyl-ammonium chloride) (PDDA) coated graphene sheet (P-GS@QDs) via self-assembly electrostatic reactions, which were used to label secondary antibodies. The ECL immunosensors coupled with a microfluidic strategy exhibited a wide detection range (0.005–50 U mL −1 ) and a low detection limit (1.2 mU mL −1 ) with the help of an external magnetic field to gather immunosensors. The method was evaluated with clinical serum sample, receiving good correlation with results from commercially available analytical procedure

  1. A sensitive label-free electrochemical immunosensor for detection of cytokeratin 19 fragment antigen 21-1 based on 3D graphene with gold nanopaticle modified electrode.

    Science.gov (United States)

    Zeng, Yan; Bao, Jing; Zhao, Yanan; Huo, Danqun; Chen, Mei; Yang, Mei; Fa, Huanbao; Hou, Changjun

    2018-02-01

    Previous studies have confirmed that cytokeratin 19 fragment antigen 21-1 (CYFRA 21-1) serves as a powerful biomarker in non-small cell lung cancer (NSCLC). Herein, we report for the first time a label-free electrochemical immunosensor for sensitive and selective detection of tumor marker CYFRA21-1. In this work, three-dimensional graphene @ gold nanoparticles (3D-G@Au) nanocomposite was modified on the glassy carbon electrode (GCE) surface to enhance the conductivity of immunosensor. The anti-CYFRA21-1 captured and fixed on the modified GCE through the cross-linking of chitosan (CS), glutaraldehyde (GA) and anti-CYFRA21-1. The differential pulse voltammetry (DPV) peak current change due to the specific interaction between anti-CYFRA21-1 and CYFRA21-1 on the modified electrode surface was utilized to detect CYFRA21-1. Under optimized conditions, the proposed electrochemical immunosensor was employed to detect CYFRA21-1 and exhibited a wide linear range of 0.25-800ngmL -1 and low detection limit of 100pgmL -1 (S/N = 3). Moreover, the recovery rates of serum samples were in the range from 95.2% to 108.7% and the developed immunosensor also shows a good correlation (less than 6.6%) with enzyme-linked immunosorbent assay (ELISA) in the detection of clinical serum samples. Therefore, it is expected that the proposed immunosensor based on a 3D-G@Au has great potential in clinical medical diagnosis of CYFRA21-1. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. URANIUM LEACHING AND RECOVERY PROCESS

    Science.gov (United States)

    McClaine, L.A.

    1959-08-18

    A process is described for recovering uranium from carbonate leach solutions by precipitating uranium as a mixed oxidation state compound. Uranium is recovered by adding a quadrivalent uranium carbon;te solution to the carbonate solution, adjusting the pH to 13 or greater, and precipitating the uranium as a filterable mixed oxidation state compound. In the event vanadium occurs with the uranium, the vanadium is unaffected by the uranium precipitation step and remains in the carbonate solution. The uranium-free solution is electrolyzed in the cathode compartment of a mercury cathode diaphragm cell to reduce and precipitate the vanadium.

  3. Trends in uranium supply

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, M [International Atomic Energy Agency, Division of Nuclear Power and Reactors, Nuclear Materials and Fuel Cycle Section, Vienna (Austria)

    1976-07-01

    Prior to the development of nuclear power, uranium ores were used to a very limited extent as a ceramic colouring agent, as a source of radium and in some places as a source of vanadium. Perhaps before that, because of the bright orange and yellow colours of its secondary ores, it was probably used as ceremonial paint by primitive man. After the discovery of nuclear fission a whole new industry emerged, complete with its problems of demand, resources and supply. Spurred by special incentives in the early years of this new nuclear industry, prospectors discovered over 20 000 occurrences of uranium in North America alone, and by 1959 total world production reached a peak of 34 000 tonnes uranium from mines in South Africa, Canada and United States. This rapid growth also led to new problems. As purchases for military purposes ended, government procurement contracts were not renewed, and the large reserves developed as a result of government purchase incentives, in combination with lack of substantial commercial market, resulted in an over-supply of uranium. Typically, an over-supply of uranium together with national stockpiling at low prices resulted in depression of prices to less than $5 per pound by 1971. Although forecasts made in the early 1970's increased confidence in the future of nuclear power, and consequently the demand for uranium, prices remained low until the end of 1973 when OPEC announced a very large increase in oil prices and quite naturally, prices for coal also rose substantially. The economics of nuclear fuel immediately improved and prices for uranium began to climb in 1974. But the world-wide impact of the OPEC decision also produced negative effects on the uranium industry. Uranium production costs rose dramatically, as did capital costs, and money for investment in new uranium ventures became more scarce and more expensive. However, the uranium supply picture today offers hope of satisfactory development in spite of the many problems to be

  4. Uranium industry annual 1993

    International Nuclear Information System (INIS)

    1994-09-01

    Uranium production in the United States has declined dramatically from a peak of 43.7 million pounds U 3 O 8 (16.8 thousand metric tons uranium (U)) in 1980 to 3.1 million pounds U 3 O 8 (1.2 thousand metric tons U) in 1993. This decline is attributed to the world uranium market experiencing oversupply and intense competition. Large inventories of uranium accumulated when optimistic forecasts for growth in nuclear power generation were not realized. The other factor which is affecting U.S. uranium production is that some other countries, notably Australia and Canada, possess higher quality uranium reserves that can be mined at lower costs than those of the United States. Realizing its competitive advantage, Canada was the world's largest producer in 1993 with an output of 23.9 million pounds U 3 O 8 (9.2 thousand metric tons U). The U.S. uranium industry, responding to over a decade of declining market prices, has downsized and adopted less costly and more efficient production methods. The main result has been a suspension of production from conventional mines and mills. Since mid-1992, only nonconventional production facilities, chiefly in situ leach (ISL) mining and byproduct recovery, have operated in the United States. In contrast, nonconventional sources provided only 13 percent of the uranium produced in 1980. ISL mining has developed into the most cost efficient and environmentally acceptable method for producing uranium in the United States. The process, also known as solution mining, differs from conventional mining in that solutions are used to recover uranium from the ground without excavating the ore and generating associated solid waste. This article describes the current ISL Yang technology and its regulatory approval process, and provides an analysis of the factors favoring ISL mining over conventional methods in a declining uranium market

  5. Trends in uranium supply

    International Nuclear Information System (INIS)

    Hansen, M.

    1976-01-01

    Prior to the development of nuclear power, uranium ores were used to a very limited extent as a ceramic colouring agent, as a source of radium and in some places as a source of vanadium. Perhaps before that, because of the bright orange and yellow colours of its secondary ores, it was probably used as ceremonial paint by primitive man. After the discovery of nuclear fission a whole new industry emerged, complete with its problems of demand, resources and supply. Spurred by special incentives in the early years of this new nuclear industry, prospectors discovered over 20 000 occurrences of uranium in North America alone, and by 1959 total world production reached a peak of 34 000 tonnes uranium from mines in South Africa, Canada and United States. This rapid growth also led to new problems. As purchases for military purposes ended, government procurement contracts were not renewed, and the large reserves developed as a result of government purchase incentives, in combination with lack of substantial commercial market, resulted in an over-supply of uranium. Typically, an over-supply of uranium together with national stockpiling at low prices resulted in depression of prices to less than $5 per pound by 1971. Although forecasts made in the early 1970's increased confidence in the future of nuclear power, and consequently the demand for uranium, prices remained low until the end of 1973 when OPEC announced a very large increase in oil prices and quite naturally, prices for coal also rose substantially. The economics of nuclear fuel immediately improved and prices for uranium began to climb in 1974. But the world-wide impact of the OPEC decision also produced negative effects on the uranium industry. Uranium production costs rose dramatically, as did capital costs, and money for investment in new uranium ventures became more scarce and more expensive. However, the uranium supply picture today offers hope of satisfactory development in spite of the many problems to be

  6. Uranium industry annual 1993

    Energy Technology Data Exchange (ETDEWEB)

    1994-09-01

    Uranium production in the United States has declined dramatically from a peak of 43.7 million pounds U{sub 3}O{sub 8} (16.8 thousand metric tons uranium (U)) in 1980 to 3.1 million pounds U{sub 3}O{sub 8} (1.2 thousand metric tons U) in 1993. This decline is attributed to the world uranium market experiencing oversupply and intense competition. Large inventories of uranium accumulated when optimistic forecasts for growth in nuclear power generation were not realized. The other factor which is affecting U.S. uranium production is that some other countries, notably Australia and Canada, possess higher quality uranium reserves that can be mined at lower costs than those of the United States. Realizing its competitive advantage, Canada was the world`s largest producer in 1993 with an output of 23.9 million pounds U{sub 3}O{sub 8} (9.2 thousand metric tons U). The U.S. uranium industry, responding to over a decade of declining market prices, has downsized and adopted less costly and more efficient production methods. The main result has been a suspension of production from conventional mines and mills. Since mid-1992, only nonconventional production facilities, chiefly in situ leach (ISL) mining and byproduct recovery, have operated in the United States. In contrast, nonconventional sources provided only 13 percent of the uranium produced in 1980. ISL mining has developed into the most cost efficient and environmentally acceptable method for producing uranium in the United States. The process, also known as solution mining, differs from conventional mining in that solutions are used to recover uranium from the ground without excavating the ore and generating associated solid waste. This article describes the current ISL Yang technology and its regulatory approval process, and provides an analysis of the factors favoring ISL mining over conventional methods in a declining uranium market.

  7. Uranium geochemistry, mineralogy, geology, exploration and resources

    International Nuclear Information System (INIS)

    De Vivo, B.

    1984-01-01

    This book comprises papers on the following topics: history of radioactivity; uranium in mantle processes; transport and deposition of uranium in hydrothermal systems at temperatures up to 300 0 C: Geological implications; geochemical behaviour of uranium in the supergene environment; uranium exploration techniques; uranium mineralogy; time, crustal evolution and generation of uranium deposits; uranium exploration; geochemistry of uranium in the hydrographic network; uranium deposits of the world, excluding Europe; uranium deposits in Europe; uranium in the economics of energy; role of high heat production granites in uranium province formation; and uranium deposits

  8. Uranium enrichment techniques

    International Nuclear Information System (INIS)

    Hamdoun, N.A.

    2007-01-01

    This article includes an introduction about the isotopes of natural uranium, their existence and the difficulty of the separation between them. Then it goes to the details of a number of methods used to enrich uranium: Gaseous Diffusion method, Electromagnetic method, Jet method, Centrifugal method, Chemical method, Laser method and Plasma method.

  9. Uranium dioxide pellets

    International Nuclear Information System (INIS)

    Zawidzki, T.W.

    1979-01-01

    Sintered uranium dioxide pellets composed of particles of size > 50 microns suitable for power reactor use are made by incorporating a small amount of sulphur into the uranium dioxide before sintering. The increase in grain size achieved results in an improvement in overall efficiency when such pellets are used in a power reactor. (author)

  10. Uranium's scientific history

    International Nuclear Information System (INIS)

    Goldschmidt, B.

    1990-01-01

    The bicentenary of the discovery of uranium coincides with the fiftieth anniversary of the discovery of fission, an event of worldwide significance and the last episode in the uranium -radium saga which is the main theme of this paper. Uranium was first identified by the German chemist Martin Klaproth in 1789. He extracted uranium oxide from the ore pitchblende which was a by-product of the silver mines at Joachimsthal in Bohemia. For over a century after its discovery, the main application for uranium derived from the vivid colours of its oxides and salts which are used in glazes for ceramics, and porcelain. In 1896, however, Becquerel discovered that uranium emitted ionizing radiation. The extraction by Pierre and Marie Curie of the more radioactive radium from uranium in the early years of the twentieth century and its application to the treatment of cancer shifted the chief interest to radium production. In the 1930s the discovery of the neutron and of artificial radioactivity stimulated research in a number of European laboratories which culminated in the demonstration of fission by Otto Frisch in January 1939. The new found use of uranium for the production of recoverable energy, and the creation of artificial radioelements in nuclear reactors, eliminated the radium industry. (author)

  11. Uranium: biokinetics and toxicity

    International Nuclear Information System (INIS)

    Menetrier, F.; Renaud-Salis, V.; Flury-Herard, A.

    2000-01-01

    This report was achieved as a part of a collaboration with the Fuel Cycle Direction. Its aim was to give the state of the art about: the behaviour of uranium in the human organism (biokinetics) after ingestion, its toxicity (mainly renal) and the current regulation about its incorporation. Both in the upstream and in the downstream of the fuel cycle, uranium remains, quantitatively, the first element in the cycle which is, at the present time, temporarily disposed or recycled. Such a considerable quantity of uranium sets the problem of its risk on the health. In the long term, the biosphere may be affected and consequently the public may ingest water or food contaminated with uranium. In this way, radiological and chemical toxicity risk may be activated. This report emphasizes: the necessity of confirming some experimental and epidemiological biokinetic data used or not in the ICRP models. Unsolved questions remain about the gastrointestinal absorption according to chemical form (valency state, mixtures...), mass and individual variations (age, disease) further a chronic ingestion of uranium. It is well established that uranium is mainly deposited in the skeleton and the kidney. But the skeleton kinetics following a chronic ingestion and especially in some diseases has to be more elucidated; the necessity of taking into account uranium at first as a chemical toxic, essentially in the kidney and determining the threshold of functional lesion. In this way, it is important to look for some specific markers; the problem of not considering chemical toxicity of uranium in the texts regulating its incorporation

  12. Rheinbraun's Australian uranium business

    International Nuclear Information System (INIS)

    Kirschbaum, S.

    1989-01-01

    The leaflet argues against the mining activities of the Rheinische Braunkohlenwerke AG in Germany and especially against uranium mining in Australia. The ethno-ecological impact on flora and fauna, aborigines and miners are pointed out. Uranium mining and lignite mining are compared. (HSCH) [de

  13. Australia and uranium

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    A brief justification of the Australian Government's decision to mine and export Australian Uranium is presented along with a description of the Alligator River Region in the Northern Territory where the major mines are to be located. Aboriginal interests and welfare in the region, the proposed Kakadu National Park and the economic benefits resulting from uranium development are also briefly covered. (J.R.)

  14. Nuclear and uranium policies

    International Nuclear Information System (INIS)

    MacNabb, G.M.; Uranium Canada Ltd., Ottawa, Ontario)

    The background of the uranium industry in Canada is described. Government policies with respect to ownership of the uranium mining industry, price stabilization, and especially reservation of sufficient supplies of nuclear fuels for domestic utilities, are explained. Canadian policy re nuclear exports and safeguards is outlined. (E.C.B.)

  15. Uranium and transuranium analysis

    International Nuclear Information System (INIS)

    Regnaud, F.

    1989-01-01

    Analytical chemistry of uranium, neptunium, plutonium, americium and curium is reviewed. Uranium and neptunium are mainly treated and curium is only briefly evoked. Analysis methods include coulometry, titration, mass spectrometry, absorption spectrometry, spectrofluorometry, X-ray spectrometry, nuclear methods and radiation spectrometry [fr

  16. Preparation of uranium tetrafluoride

    International Nuclear Information System (INIS)

    Wirths, G.

    1981-01-01

    Uranium dioxide is converted to uranium tetrafluoride under stoichiometric excess of hydrogen fluoride. The water formed in the process and the unreacted hydrogen fluoride are cooled and the condensate fractionally distilled into water and approx. 40% hydrofluoric acid. The hydrofluoric acid and water-free hydrogen fluoride are fed back into the process. (WI) [de

  17. Rossing uranium 1979

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    This report describes the activities and organization of the Rossing uranium mine in South West Africa. The development of the mine during the last six years is described as well as the geology of the uranium deposits and aspects of the mining operations. The manpower structure and training possibilities for personnel are described

  18. Management of depleted uranium

    International Nuclear Information System (INIS)

    2001-01-01

    Large stocks of depleted uranium have arisen as a result of enrichment operations, especially in the United States and the Russian Federation. Countries with depleted uranium stocks are interested in assessing strategies for the use and management of depleted uranium. The choice of strategy depends on several factors, including government and business policy, alternative uses available, the economic value of the material, regulatory aspects and disposal options, and international market developments in the nuclear fuel cycle. This report presents the results of a depleted uranium study conducted by an expert group organised jointly by the OECD Nuclear Energy Agency and the International Atomic Energy Agency. It contains information on current inventories of depleted uranium, potential future arisings, long term management alternatives, peaceful use options and country programmes. In addition, it explores ideas for international collaboration and identifies key issues for governments and policy makers to consider. (authors)

  19. Uranium dioxide electrolysis

    Science.gov (United States)

    Willit, James L [Batavia, IL; Ackerman, John P [Prescott, AZ; Williamson, Mark A [Naperville, IL

    2009-12-29

    This is a single stage process for treating spent nuclear fuel from light water reactors. The spent nuclear fuel, uranium oxide, UO.sub.2, is added to a solution of UCl.sub.4 dissolved in molten LiCl. A carbon anode and a metallic cathode is positioned in the molten salt bath. A power source is connected to the electrodes and a voltage greater than or equal to 1.3 volts is applied to the bath. At the anode, the carbon is oxidized to form carbon dioxide and uranium chloride. At the cathode, uranium is electroplated. The uranium chloride at the cathode reacts with more uranium oxide to continue the reaction. The process may also be used with other transuranic oxides and rare earth metal oxides.

  20. Uranium deposit research, 1983

    International Nuclear Information System (INIS)

    Ruzicka, V.; LeCheminant, G.M.

    1984-01-01

    Research on uranium deposits in Canada, conducted as a prerequisite for assessment of the Estimated Additional Resources of uranium, revealed that (a) the uranium-gold association in rudites of the Huronian Supergroup preferably occurs in the carbon layers; (b) chloritized ore at the Panel mine, Elliot Lake, Ontario, occurs locally in tectonically disturbed areas in the vicinity of diabase dykes; (c) mineralization in the Black Sturgeon Lake area, Ontario, formed from solutions in structural and lithological traps; (d) the Cigar Lake deposit, Saskatchewan, has two phases of mineralization: monomineralic and polymetallic; (e) mineralization of the JEB (Canoxy Ltd.) deposit is similar to that at McClean Lake; (f) the uranium-carbon assemblage was identified in the Claude deposit, Carswell Structure; and (g) the Otish Mountains area, Quebec, should be considered as a significant uranium-polymetallic metallogenic province

  1. Uranium oxide recovering method

    International Nuclear Information System (INIS)

    Ota, Kazuaki; Takazawa, Hiroshi; Teramae, Naoki; Onoue, Takeshi.

    1997-01-01

    Nitrates containing uranium nitrate are charged in a molten salt electrolytic vessel, and a heat treatment is applied to prepare molten salts. An anode and a cathode each made of a graphite rod are disposed in the molten salts. AC voltage is applied between the anode and the cathode to conduct electrolysis of the molten salts. Uranium oxides are deposited as a recovered product of uranium, on the surface of the anode. The nitrates containing uranium nitrate are preferably a mixture of one or more nitrates selected from sodium nitrate, potassium nitrate, calcium nitrate and magnesium nitrate with uranium nitrate. The nitrates may be liquid wastes of nitrates. The temperature for the electrolysis of the molten salts is preferably from 150 to 300degC. The voltage for the electrolysis of the molten salts is preferably an AC voltage of from 2 to 6V, more preferably from 4 to 6V. (I.N.)

  2. Uranium mines of Tajikistan

    International Nuclear Information System (INIS)

    Razykov, Z.A; Gusakov, E.G.; Marushenko, A.A.; Botov, A.Yu.; Yunusov, M.M.

    2002-12-01

    The book describes location laws, the main properties of geological structure and industrial perspectives for known uranium mines of the Republic of Tajikistan. Used methods of industrial processing of uranium mines are described. The results of investigations of technological properties of main types of uranium ores and methods of industrial processing of some of them are shown. Main properties of uranium are shortly described as well as problems, connected with it, which arise during exploitation, mining and processing of uranium ores. The main methods of solution of these problems are shown. The book has interest for specialists of mining, geological, chemical, and technological fields as well as for students of appropriate universities. This book will be interested for usual reader, too, if they are interested in mineral resources of their country [ru

  3. Uranium chemistry research unit

    International Nuclear Information System (INIS)

    Anon.

    1978-01-01

    The initial field of research of this Unit, established in 1973, was the basic co-ordination chemistry of uranium, thorium, copper, cobalt and nickel. Subsequently the interest of the Unit extended to extractive metallurgy relating to these metals. Under the term 'co-ordination chemistry' is understood the interaction of the central transition metal ion with surrounding atoms in its immediate vicinity (within bonding distance) and the influence they have on each other - for example, structural studies for determining the number and arrangement of co-ordinated atoms and spectrophotometric studies to establish how the f electron energy levels of uranium are influenced by the environment. New types of uranium compounds have been synthesized and studied, and the behaviour of uranium ions in non-aqueous systems has also received attention. This work can be applied to the development and study of extractants and new extractive processes for uranium

  4. Jabiluka uranium project

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    The Jabiluka uranium and gold deposit located in the Northern Territory of Australia is the world's largest known primary uranium deposits and as such has the potential to become one of the most important uranium projects in the world. Despite the financial and structural challenges facing the major owner Pancontinental Mining Limited and the changing political policies in Australia, Jabiluka is well situated for development during the 1990's. With the availability of numerous financial and development alternatives, Jabiluka could, by the turn of the century, take its rightful place among the first rank of world uranium producers. The paper discusses ownership, location, property rights, licensing, environmental concerns, marketing and development, capital costs, royalties, uranium policy considerations, geologic exploration history, regional and site geology, and mining and milling operations

  5. EPR of uranium ions

    International Nuclear Information System (INIS)

    Ursu, I.; Lupei, V.

    1984-02-01

    A review of the electron paramagnetic resonance data on the uranium ions is given. After a general account of the electronic structure of the uranium free atoms and ions, the influence of the external fields (magnetic field, crystal fields) is discussed. The main information obtained from EPR studies on the uranium ions in crystals are emphasized: identification of the valence and of the ground electronic state, determination of the structure of the centers, crystal field effects, role of the intermediate coupling and of the J-mixing, role of the covalency, determination of the nuclear spin, maqnetic dipole moment and electric quadrupole moment of the odd isotopes of uranium. These data emphasize the fact that the actinide group has its own identity and this is accutely manifested at the beginning of the 5fsup(n) series encompassed by the uranium ions. (authors)

  6. Uranium in Canada

    International Nuclear Information System (INIS)

    1987-09-01

    Canadian uranium exploration and development efforts in 1985 and 1986 resulted in a significant increase in estimates of measured uranium resources. New discoveries have more than made up for production during 1985 and 1986, and for the elimination of some resources from the overall estimates, due to the sustained upward pressure on production costs and the stagnation of uranium prices in real terms. Canada possesses a large portion of the world's uranium resources that are of current economic interest and remains the major focus of inter-national uranium exploration activity. Expenditures for uranium exploration in Canada in 1985 and 1986 were $32 million and $33 million, respectively. Although much lower than the $130 million total reported for 1979, expenditures for 1987 are forecast to increase. Exploration and surface development drilling in 1985 and 1986 were reported to be 183 000 m and 165σ2 000 m, respectively, 85 per cent of which was in Saskatchewan. Canada has maintained its position as the world's leading producer and exporter of uranium. By the year 2000, Canada's annual uranium requirements will be about 2 100 tU. Canada's known uranium resources are more than sufficient to meet the 30-year fuel requirements of those reactors in Canada that are either in operation now or expected to be in service by the late 1990s. A substantial portion of Canada's identified uranium resources is thus surplus to Canadian needs and available for export. Annual sales currently approach $1 billion, of which exports account for 85 per cent. Forward domestic and export contract commitments totalled 73 000 tU and 62 000 tU, respectively, as of early 1987

  7. Uranium rich granite and uranium productive granite in south China

    Energy Technology Data Exchange (ETDEWEB)

    Mingyue, Feng; Debao, He [CNNC Key Laboratory of Uranium Resource Exploration and Evaluation Technology, Beijing Research Institute of Uranium Geology (China)

    2012-07-15

    The paper briefly introduces the differences between uranium rich granite and uranium productive granite in the 5 provinces of South China, and discusses their main characteristics in 4 aspects, the uranium productive granite is highly developed in fracture, very strong in alteration, often occurred as two-mica granite and regularly developed with intermediate-basic and acid dikes. The above characteristics distinguish the uranium productive granite from the uranium rich granite. (authors)

  8. Uranium rich granite and uranium productive granite in south China

    International Nuclear Information System (INIS)

    Feng Mingyue; He Debao

    2012-01-01

    The paper briefly introduces the differences between uranium rich granite and uranium productive granite in the 5 provinces of South China, and discusses their main characteristics in 4 aspects, the uranium productive granite is highly developed in fracture, very strong in alteration, often occurred as two-mica granite and regularly developed with intermediate-basic and acid dikes. The above characteristics distinguish the uranium productive granite from the uranium rich granite. (authors)

  9. Pengaruh Kandungan Uranium Dalam Umpan Terhadap Efisiensi Pengendapan Uranium

    OpenAIRE

    Torowati

    2010-01-01

    PENGARUH KANDUNGAN URANIUM DALAM UMPAN TERHADAP EFISIENSI PENGENDAPAN URANIUM. Setiap aktivitas analisis di Laboratorium Kendali Kualitas, Bidang Bahan Bakar Nuklir selalu dihasilkan limbah radioaktif cair. Limbah radioaktif cair di laboratorium masih mengandung uranium yang cukup besar ± 0,600 g U/l dengan keasamaan yang cukup besar pula. Karena uranium mempunyai nilai ekonomis yang cukup tinggi maka perlu USAha untuk mengambil kembali uranium tersebut. Pada kegiatan ini telah dilak...

  10. Uranium and the fast reactor

    International Nuclear Information System (INIS)

    Price, T.

    1982-01-01

    The influence of uranium availability upon the future of the fast reactor is reviewed. The important issues considered are uranium reserves and resources, uranium market prices, fast reactor economics and the political availability of uranium to customers in other countries. (U.K.)

  11. Uranium producers foresee new boom

    International Nuclear Information System (INIS)

    McIntyre, H.

    1979-01-01

    The status of uranium production in Canada is reviewed. Uranium resources in Saskatchewan and Ontario are described and the role of the Cluff Lake inquiry in securing a government decision in favour of further uranium development is mentioned. There have been other uranium strikes near Kelowna, British Columbia and in the Northwest Territories. Increasing uranium demand and favourable prices are making the development of northern resources economically attractive. In fact, all uranium currently produced has been committed to domestic and export contracts so that there is considerable room for expanding the production of uranium in Canada. (T.I.)

  12. Uranium tipped ammunition

    International Nuclear Information System (INIS)

    Roche, P.

    1993-01-01

    During the uranium enrichment process required to make nuclear weapons or fuel, the concentration of the 'fissile' U-235 isotope has to be increased. What is left, depleted uranium, is about half as radioactive as natural uranium, but very dense and extremely hard. It is used in armour piercing shells. External radiation levels from depleted uranium (DU) are low. However DU is about as toxic as lead and could be harmful to the kidneys if eaten or inhaled. It is estimated that between 40 and 300 tonnes of depleted uranium were left behind by the Allied armies after the Gulf war. The biggest hazard would be from depleted uranium shells which have hit Iraqui armoured vehicles and the resulting dust inhaled. There is a possible link between depleted uranium shells and an illness known as 'Desert Storm Syndrome' occurring in some Gulf war veterans. As these shells are a toxic and radioactive hazard to health and the environment their use and testing should be stopped because of the risks to troops and those living near test firing ranges. (UK)

  13. US uranium market developments

    International Nuclear Information System (INIS)

    Krusiewski, S.V.; Patterson, J.A.

    1980-01-01

    Domestic uranium delivery commitments have risen significantly since January 1979, with the bulk of deliveries scheduled after 1990. Much of the long-term procurement will be obtained from captive production. However, buyers have adjusted their delivery schedules in the near term, deferring some procurement to later years, including a portion of planned captive production. Under current commitments, US imports of foreign uranium in the 1981 to 1985 period will be greater than our exports of domestic uranium. The anticipated supply of domestic uranium through 1985 is clearly more than adequate to fill the probable US demand in the meantime, uranium producers are continuing their efforts to increase future domestic supply by their considerable investments in new or expanded mine and mill facilities. Since January 1980, average contract prices including market-price settlements, for 1980 uranium deliveries have increased slightly, but average market-price settlements made this year have decreased by several dollars. While the general trend of US uranium prices has been upward since we began reporting price data in 1973, some reductions in average prices for future deliveries appeared in 1980. The softening of prices for new procurement can be expected to be increasingly apparent in future surveys

  14. Uranium deposits in Africa

    International Nuclear Information System (INIS)

    Wilpolt, R.H.; Simov, S.D.

    1979-01-01

    Africa is not only known for its spectacular diamond, gold, copper, chromium, platinum and phosphorus deposits but also for its uranium deposits. At least two uranium provinces can be distinguished - the southern, with the equatorial sub-province; and the south Saharan province. Uranium deposits are distributed either in cratons or in mobile belts, the first of sandstone and quartz-pebble conglomerate type, while those located in mobile belts are predominantly of vein and similar (disseminated) type. Uranium deposits occur within Precambrian rocks or in younger platform sediments, but close to the exposed Precambrian basement. The Proterozoic host rocks consist of sediments, metamorphics or granitoids. In contrast to Phanerozoic continental uranium-bearing sediments, those in the Precambrian are in marginal marine facies but they do contain organic material. The geology of Africa is briefly reviewed with the emphasis on those features which might control the distribution of uranium. The evolution of the African Platform is considered as a progressive reduction of its craton area which has been affected by three major Precambrian tectonic events. A short survey on the geology of known uranium deposits is made. However, some deposits and occurrences for which little published material is available are treated in more detail. (author)

  15. Uranium chemistry: significant advances

    International Nuclear Information System (INIS)

    Mazzanti, M.

    2011-01-01

    The author reviews recent progress in uranium chemistry achieved in CEA laboratories. Like its neighbors in the Mendeleev chart uranium undergoes hydrolysis, oxidation and disproportionation reactions which make the chemistry of these species in water highly complex. The study of the chemistry of uranium in an anhydrous medium has led to correlate the structural and electronic differences observed in the interaction of uranium(III) and the lanthanides(III) with nitrogen or sulfur molecules and the effectiveness of these molecules in An(III)/Ln(III) separation via liquid-liquid extraction. Recent work on the redox reactivity of trivalent uranium U(III) in an organic medium with molecules such as water or an azide ion (N 3 - ) in stoichiometric quantities, led to extremely interesting uranium aggregates particular those involved in actinide migration in the environment or in aggregation problems in the fuel processing cycle. Another significant advance was the discovery of a compound containing the uranyl ion with a degree of oxidation (V) UO 2 + , obtained by oxidation of uranium(III). Recently chemists have succeeded in blocking the disproportionation reaction of uranyl(V) and in stabilizing polymetallic complexes of uranyl(V), opening the way to to a systematic study of the reactivity and the electronic and magnetic properties of uranyl(V) compounds. (A.C.)

  16. Production of uranium dioxide

    International Nuclear Information System (INIS)

    Hart, J.E.; Shuck, D.L.; Lyon, W.L.

    1977-01-01

    A continuous, four stage fluidized bed process for converting uranium hexafluoride (UF 6 ) to ceramic-grade uranium dioxide (UO 2 ) powder suitable for use in the manufacture of fuel pellets for nuclear reactors is disclosed. The process comprises the steps of first reacting UF 6 with steam in a first fluidized bed, preferably at about 550 0 C, to form solid intermediate reaction products UO 2 F 2 , U 3 O 8 and an off-gas including hydrogen fluoride (HF). The solid intermediate reaction products are conveyed to a second fluidized bed reactor at which the mol fraction of HF is controlled at low levels in order to prevent the formation of uranium tetrafluoride (UF 4 ). The first intermediate reaction products are reacted in the second fluidized bed with steam and hydrogen at a temperature of about 630 0 C. The second intermediate reaction product including uranium dioxide (UO 2 ) is conveyed to a third fluidized bed reactor and reacted with additional steam and hydrogen at a temperature of about 650 0 C producing a reaction product consisting essentially of uranium dioxide having an oxygen-uranium ratio of about 2 and a low residual fluoride content. This product is then conveyed to a fourth fluidized bed wherein a mixture of air and preheated nitrogen is introduced in order to further reduce the fluoride content of the UO 2 and increase the oxygen-uranium ratio to about 2.25

  17. Purification of uranium metal

    International Nuclear Information System (INIS)

    Suzuki, Kenji; Shikama, Tatsuo; Ochiai, Akira.

    1993-01-01

    We developed the system for purifying uranium metal and its metallic compounds and for growing highly pure uranium compounds to study their intrinsic physical properties. Uranium metal was zone refined under low contamination conditions as far as possible. The degree of the purity of uranium metal was examined by the conventional electrical resistivity measurement and by the chemical analysis using the inductive coupled plasma emission spectrometry (ICP). The results show that some metallic impurities evaporated by the r.f. heating and other usual metallic impurities moved to the end of a rod with a molten zone. Therefore, we conclude that the zone refining technique is much effective to the removal of metallic impurities and we obtained high purified uranium metal of 99.99% up with regarding to metallic impurities. The maximum residual resistivity ratio, the r.r.r., so far obtained was about 17-20. Using the purified uranium, we are attempting to grow a highly pure uranium-titanium single crystals. (author)

  18. Strong demand for natural uranium

    International Nuclear Information System (INIS)

    Kalinowski, P.

    1975-01-01

    The Deutsches Atomforum and the task group 'fuel elements' of the Kerntechnische Gesellschaft had organized an international two-day symposium in Mainz on natural uranium supply which was attended by 250 experts from 20 countries. The four main themes were: Demand for natural uranium, uranium deposits and uranium production, attitude of the uranium producing countries, and energy policy of the industrial nations. (orig./AK) [de

  19. The uranium equation in 1982

    International Nuclear Information System (INIS)

    Bonny, J.; Fulton, M.

    1983-01-01

    The subject is discussed under the headings: comparison of world nuclear generating capacity forecasts; world uranium requirements; comparison of uranium production capability forecasts; supply and demand situation in 1990 and 1995; a perspective on the uranium equation (economic factors; development lead times as a factor affecting market stability; the influence of uncertainty; the uranium market in perspective; the uranium market in 1995). (U.K.)

  20. Uranium resource assessments

    International Nuclear Information System (INIS)

    1981-01-01

    The objective of this investigation is to examine what is generally known about uranium resources, what is subject to conjecture, how well do the explorers themselves understand the occurrence of uranium, and who are the various participants in the exploration process. From this we hope to reach a better understanding of the quality of uranium resource estimates as well as the nature of the exploration process. The underlying questions will remain unanswered. But given an inability to estimate precisely our uranium resources, how much do we really need to know. To answer this latter question, the various Department of Energy needs for uranium resource estimates are examined. This allows consideration of whether or not given the absence of more complete long-term supply data and the associated problems of uranium deliverability for the electric utility industry, we are now threatened with nuclear power plants eventually standing idle due to an unanticipated lack of fuel for their reactors. Obviously this is of some consequence to the government and energy consuming public. The report is organized into four parts. Section I evaluates the uranium resource data base and the various methodologies of resource assessment. Part II describes the manner in which a private company goes about exploring for uranium and the nature of its internal need for resource information. Part III examines the structure of the industry for the purpose of determining the character of the industry with respect to resource development. Part IV arrives at conclusions about the emerging pattern of industrial behavior with respect to uranium supply and the implications this has for coping with national energy issues

  1. Vacuum fusion of uranium

    International Nuclear Information System (INIS)

    Stohr, J.A.

    1957-01-01

    After having outlined that vacuum fusion and moulding of uranium and of its alloys have some technical and economic benefits (vacuum operations avoid uranium oxidation and result in some purification; precision moulding avoids machining, chip production and chemical reprocessing of these chips; direct production of the desired shape is possible by precision moulding), this report presents the uranium fusion unit (its low pressure enclosure and pumping device, the crucible-mould assembly, and the MF supply device). The author describes the different steps of cast production, and briefly comments the obtained results

  2. Depleted uranium management alternatives

    Energy Technology Data Exchange (ETDEWEB)

    Hertzler, T.J.; Nishimoto, D.D.

    1994-08-01

    This report evaluates two management alternatives for Department of Energy depleted uranium: continued storage as uranium hexafluoride, and conversion to uranium metal and fabrication to shielding for spent nuclear fuel containers. The results will be used to compare the costs with other alternatives, such as disposal. Cost estimates for the continued storage alternative are based on a life-cycle of 27 years through the year 2020. Cost estimates for the recycle alternative are based on existing conversion process costs and Capital costs for fabricating the containers. Additionally, the recycle alternative accounts for costs associated with intermediate product resale and secondary waste disposal for materials generated during the conversion process.

  3. Uranium absorption study pile

    International Nuclear Information System (INIS)

    Raievski, V.; Sautiez, B.

    1959-01-01

    The report describes a pile designed to measure the absorption of fuel slugs. The pile is of graphite and comprises a central section composed of uranium rods in a regular lattice. RaBe sources and BF 3 counters are situated on either side of the center. A given uranium charge is compared with a specimen charge of about 560 kg, and the difference in absorption between the two noted. The sensitivity of the equipment will detect absorption variations of about a few ppm boron (10 -6 boron per gr. of uranium) or better. (author) [fr

  4. The politics of uranium

    International Nuclear Information System (INIS)

    Moss, N.

    1981-01-01

    The subject is covered in chapters, entitled: what God hath joined (historical and technical summary of the atomic bomb project and the post-war attempt at international control of atomic energy); finding uranium and using it; atoms for peace; nuclear optimists (development of nuclear power); the Treaty brake (Non-Proliferation Treaty); bending the rules; plowshares and swords; the club and the gambler (uranium production industry); turnabout (government policies); the uranium cycle; nuclear conflict; tiger in the nursery (radiation hazards; nuclear controversy); breaking the rules (proliferation); new answers, old questions. (U.K.)

  5. Uranium thiolate complexes

    International Nuclear Information System (INIS)

    Leverd, Pascal C.

    1994-01-01

    This research thesis proposes a new approach to the chemistry of uranium thiolate complexes as these compounds are very promising for various uses (in bio-inorganic chemistry, in some industrial processes like oil desulphurization). It more particularly addresses the U-S bond or more generally bonds between polarizable materials and hard metals. The author thus reports the study of uranium organometallic thiolates (tricyclo-penta-dienic and mono-cyclo-octa-tetraenylic complexes), and of uranium homoleptic thiolates (tetra-thiolate complexes, hexa-thiolate complexes, reactivity of homoleptic thiolate complexes) [fr

  6. Uranium mining and milling

    International Nuclear Information System (INIS)

    Floeter, W.

    1976-01-01

    In this report uranium mining and milling are reviewed. The fuel cycle, different types of uranium geological deposits, blending of ores, open cast and underground mining, the mining cost and radiation protection in mines are treated in the first part of this report. In the second part, the milling of uranium ores is treated, including process technology, acid and alkaline leaching, process design for physical and chemical treatment of the ores, and the cost. Each chapter is clarified by added figures, diagrams, tables, and flowsheets. (HK) [de

  7. Depleted uranium management alternatives

    International Nuclear Information System (INIS)

    Hertzler, T.J.; Nishimoto, D.D.

    1994-08-01

    This report evaluates two management alternatives for Department of Energy depleted uranium: continued storage as uranium hexafluoride, and conversion to uranium metal and fabrication to shielding for spent nuclear fuel containers. The results will be used to compare the costs with other alternatives, such as disposal. Cost estimates for the continued storage alternative are based on a life-cycle of 27 years through the year 2020. Cost estimates for the recycle alternative are based on existing conversion process costs and Capital costs for fabricating the containers. Additionally, the recycle alternative accounts for costs associated with intermediate product resale and secondary waste disposal for materials generated during the conversion process

  8. Fabrication of an electrically conductive mixed self-assembled monolayer and its application in an electrochemical immunosensor

    International Nuclear Information System (INIS)

    Lee, Jung Bae; Namgung, Miok; Lee, Sang-Baek; Oh, Se Young

    2008-01-01

    Oligophenylethynylene thiol containing carboxylic acid in the tail group as a conducting wire bioreceptor was synthesized, and then its electrical property was investigated from the measurement of scanning tunneling microscopy (STM). Mixed self-assembled monolayer (SAM) consisting of 4-(2-(4-acetylthio)phenyl)ethynyl) benzoic acid (APBA) and butanethiol was fabricated in order to improve the electrical conductivity owing to the molecular orientation. We have examined the molecular orientation and the electrochemical activity of mixed SAM via X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV). Especially, the prepared mixed SAM used as a bioreceptor in electrochemical prostate specific antigen (PSA) immunosensor showed higher electrochemical activity than that of the other SAMs

  9. A Label-Free and Ultrasensitive Immunosensor for Detection of Human Chorionic Gonadotrophin Based on Graphene FETs.

    Science.gov (United States)

    Islam, Kamrul; Suhail, Ahmed; Pan, Genhua

    2017-07-12

    We report on a label-free immunosensor based on graphene field effect transistors (G-FETs) for the ultrasensitive detection of Human Chorionic Gonadotrophin (hCG), as an indicator of pregnancy and related disorders, such as actopic pregnancy, choriocarcinoma and orchic teratoma. Pyrene based bioactive ester was non-covalently anchored onto the graphene channel in order to retain the sp² lattice. The G-FET transfer characteristics showed repeatable and reliable responses in all surface modifying steps using a direct current (DC) readout system. The hCG concentration gradient showed a detection limit of ~1 pg·mL -1 . The proposed method facilitates the cost-effective and viable production of graphene point-of-care devices for clinical diagnosis.

  10. A Novel Method for Preparation of Gold NanoBipyramids Using Microwave Irradiation and Its Application in Immunosensors

    Science.gov (United States)

    Huynh, Trong Phat; Ngo, Vo Ke Thanh; Nguyen, Dang Giang; Nguyen, Hoang Phuong Uyen; Nghiem, Quoc Dat; Lam, Quang Vinh; Huynh, Thanh Dat

    2016-05-01

    Gold nanobipyramids (NBPs) have attracted attention for producing smart sensing devices as diagnostic tools in biotechnological and medical applications, because they show more advantageous plasmonic properties than comparable gold nanorods. Normally, NBPs were synthesized using seed-mediated growth process at room temperature. In this report, our group describes a method for synthesising of NBPs using microwave irradiation with ascorbic acid reduction and cetyltrimethylammonium bromide + silver nitrate (AgNO3) as capping agents. The advantages of this method are a highly effective approach to fast and uniform NBPs. The product was characterized by ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, and x-ray powder diffraction. As an application in quartz crystal microbalance immunosensors, NBPs is conjugated with the chloramphenicol antibodies for signal amplification to detect chloramphenicol residuals in the QCM system.

  11. A Label-Free and Ultrasensitive Immunosensor for Detection of Human Chorionic Gonadotrophin Based on Graphene FETs

    Directory of Open Access Journals (Sweden)

    Kamrul Islam

    2017-07-01

    Full Text Available We report on a label-free immunosensor based on graphene field effect transistors (G-FETs for the ultrasensitive detection of Human Chorionic Gonadotrophin (hCG, as an indicator of pregnancy and related disorders, such as actopic pregnancy, choriocarcinoma and orchic teratoma. Pyrene based bioactive ester was non-covalently anchored onto the graphene channel in order to retain the sp2 lattice. The G-FET transfer characteristics showed repeatable and reliable responses in all surface modifying steps using a direct current (DC readout system. The hCG concentration gradient showed a detection limit of ~1 pg·mL−1. The proposed method facilitates the cost-effective and viable production of graphene point-of-care devices for clinical diagnosis.

  12. Visual and efficient immunosensor technique for advancing biomedical applications of quantum dots on Salmonella detection and isolation

    Science.gov (United States)

    Tang, Feng; Pang, Dai-Wen; Chen, Zhi; Shao, Jian-Bo; Xiong, Ling-Hong; Xiang, Yan-Ping; Xiong, Yan; Wu, Kai; Ai, Hong-Wu; Zhang, Hui; Zheng, Xiao-Li; Lv, Jing-Rui; Liu, Wei-Yong; Hu, Hong-Bing; Mei, Hong; Zhang, Zhen; Sun, Hong; Xiang, Yun; Sun, Zi-Yong

    2016-02-01

    It is a great challenge in nanotechnology for fluorescent nanobioprobes to be applied to visually detect and directly isolate pathogens in situ. A novel and visual immunosensor technique for efficient detection and isolation of Salmonella was established here by applying fluorescent nanobioprobes on a specially-designed cellulose-based swab (a solid-phase enrichment system). The selective and chromogenic medium used on this swab can achieve the ultrasensitive amplification of target bacteria and form chromogenic colonies in situ based on a simple biochemical reaction. More importantly, because this swab can serve as an attachment site for the targeted pathogens to immobilize and immunologically capture nanobioprobes, our mAb-conjugated QD bioprobes were successfully applied on the solid-phase enrichment system to capture the fluorescence of targeted colonies under a designed excitation light instrument based on blue light-emitting diodes combined with stereomicroscopy or laser scanning confocal microscopy. Compared with the traditional methods using 4-7 days to isolate Salmonella from the bacterial mixture, this method took only 2 days to do this, and the process of initial screening and preliminary diagnosis can be completed in only one and a half days. Furthermore, the limit of detection can reach as low as 101 cells per mL Salmonella on the background of 105 cells per mL non-Salmonella (Escherichia coli, Proteus mirabilis or Citrobacter freundii, respectively) in experimental samples, and even in human anal ones. The visual and efficient immunosensor technique may be proved to be a favorable alternative for screening and isolating Salmonella in a large number of samples related to public health surveillance.It is a great challenge in nanotechnology for fluorescent nanobioprobes to be applied to visually detect and directly isolate pathogens in situ. A novel and visual immunosensor technique for efficient detection and isolation of Salmonella was established here

  13. Possible uranium sources of Streltsovsky uranium ore field

    International Nuclear Information System (INIS)

    Zhang Lisheng

    2005-01-01

    The uranium deposit of the Late Jurassic Streltsovaky caldera in Transbaikalia of Russia is the largest uranium field associated with volcanics in the world, its uranium reserves are 280 000 t U, and it is the largest uranium resources in Russia. About one third of the caldera stratigraphic pile consists of strongly-altered rhyolites. Uranium resources of the Streltsovsky caldera are much larger than any other volcanic-related uranium districts in the world. Besides, the efficiency of hydrothermal alteration, uranium resources appear to result from the juxtaposition of two major uranium sources; highly fractionated peralkaline rhyolites of Jurassic age in the caldera, and U-rich subalkaline granites of Variscan age in the basement in which the major uranium-bearing accessory minerals were metamict at the time of the hydrothermal ore formation. (authors)

  14. Effective antibodies immobilization and functionalized nanoparticles in a quartz-crystal microbalance-based immunosensor for the detection of parathion.

    Directory of Open Access Journals (Sweden)

    Bartolomeo Della Ventura

    Full Text Available Biosensor-based detection provides a rapid and low-cost alternative to conventional analytical methods for revealing the presence of the contaminants in water as well as solid matrices. Although important to be detected, small analytes (few hundreds of Daltons are an issue in biosensing since the signal they induce in the transducer, and specifically in a Quartz-Crystal Microbalance, is undetectable. A pesticide like parathion (M = 292 Da is a typical example of contaminant for which a signal amplification procedure is desirable.The ballasting of the analyte by gold nanoparticles has been already applied to heavy target as proteins or bacteria to improve the limit of detection. In this paper, we extend the application of such a method to small analytes by showing that once the working surface of a Quartz-Crystal Microbalance (QCM has been properly functionalized, a limit of detection lower than 1 ppb is reached for parathion. The effective surface functionalization is achieved by immobilizing antibodies upright oriented on the QCM gold surface by a simple photochemical technique (Photonic Immobilization Technique, PIT based on the UV irradiation of the antibodies, whereas a simple protocol provided by the manufacturer is applied to functionalize the gold nanoparticles. Thus, in a non-competitive approach, the small analyte is made detectable by weighing it down through a "sandwich protocol" with a second antibody tethered to heavy gold nanoparticles. The immunosensor has been proved to be effective against the parathion while showing no cross reaction when a mixture of compounds very similar to parathion is analyzed.The immunosensor described in this paper can be easily applied to any small molecule for which polyclonal antibodies are available since both the functionalization procedure of the QCM probe surface and gold nanoparticle can be applied to any IgG, thereby making our device of general application in terms of target analyte.

  15. An Ultrasensitive Electrochemical Immunosensor for Alpha-Fetoprotein Using an Envision Complex-Antibody Copolymer as a Sensitive Label

    Science.gov (United States)

    Xiong, Ping; Gan, Ning; Cao, Yuting; Hu, Futao; Li, Tianhua; Zheng, Lei

    2012-01-01

    A novel strategy is presented for sensitive detection of alfa-fetoprotein (AFP), using a horseradish peroxidase (HRP)-functionalized Envision antibody complex (EVC) as the label. The Envision-AFP signal antibody copolymer (EVC-AFP Ab2) was composed of a dextran amine skeleton anchoring more than 100 molecules of HRP and 15 molecules of secondary antibody, and acted as a signal tag in the immunosensor. The sensor was constructed using the following steps: First, gold electrode (GE) was modified with nano-gold (AuNPs) by electro-deposition in HAuCl4 solution. The high affinity of the AuNPs surface facilitates direct formation of a self-assembled thiolated protein G layer. Next, the coated GE was incubated in a solution of AFP capture antibody (AFP Ab1); these antibodies attach to the thiolated protein G layer through their non-antigenic regions, leaving the antigen binding sites for binding of target analyte. Following a sandwich immunoreaction, an EVC-AFP Ab2-AFP-AFP Ab1 immunocomplex was formed on the electrode surface, allowing large amounts of HRP on the complex to produce an amplified electrocatalytic current of hydroquinone (HQ) in the presence of hydrogen peroxide (H2O2). Highly amplified detection was achieved, with a detection limit of 2 pg/mL and a linear range of 0.005–0.2 ng/mL for AFP in 10 μL undiluted serum; this is near or below the normal levels of most cancer biomarker proteins in human serum. Measurements of AFP in the serum of cancer patients correlated strongly with standard enzyme-linked immunosorbent assays. These easily fabricated EVC-modified immunosensors show excellent promise for future fabrication of bioelectronic arrays. By varying the target biomolecules, this technique may be easily extended for use with other immunoassays, and thus represents a versatile design route.

  16. An ultrasensitive label-free electrochemiluminescent immunosensor for measuring Cry1Ab level and genetically modified crops content.

    Science.gov (United States)

    Gao, Hongfei; Wen, Luke; Wu, Yuhua; Fu, Zhifeng; Wu, Gang

    2017-11-15

    The development of genetically modified (GM) insect-resistant crops has aroused great public concern about the risks on the eco-environment resulting from a release of toxic Cry proteins (such as Cry1Ab) to the soil. Therefore, it is of crucial importance to measure the Cry proteins level and the GM crops content. Here, we have tested for the first time a method that uses novel carbon nanospheres (CNPs) label-free electrochemiluminescent (ECL) immunosensor for the ultrasensitive quantification of Cry1Ab and GM crops. In this work, novel CNPs were prepared from printer toner with a very facile approach, and linked with anti-Cry1Ab antibodies to modify a golden working electrode. The immunoreaction between Cry1Ab and its antibody formed an immunocomplex on the bioreceptor region of the sensor, which inhibited electron transfer between the electrode surface and the ECL substance, leading to a decrease of ECL response. Under the optimal conditions, the fabricated label-free ECL immunosensor determined Cry1Ab down to 3.0pgmL -1 within a linear range of 0.010-1.0ngmL -1 , showing significant improvement of sensitivity than that of most previous reports. Meanwhile, the proposed method was successfully applied for GM rice BT63 and GM maize MON810 detections down to 0.010% and 0.020%, respectively. Due to its outstanding advantages such as high sensitivity, ideal selectivity, simple fabrication, rapid detection, and low cost, the developed method can be considered as a powerful and pioneering tool for GM crops detection. Its use can also be extended to other toxin protein sensing in foods. Copyright © 2017. Published by Elsevier B.V.

  17. Rayleigh SAW-Assisted SH-SAW Immunosensor on X-Cut 148-Y LiTaO3.

    Science.gov (United States)

    Kogai, Takashi; Yatsuda, Hiromi; Kondoh, Jun

    2017-09-01

    In this paper, we describe a shear horizontal surface acoustic wave (SH-SAW) immunosensor that utilizes induce agitation by a Rayleigh SAW (R-SAW) on an X-cut 148-Y LiTaO 3 substrate. On this substrate, SH-SAWs and R-SAWs with different frequencies can be effectively generated at an interdigital transducer (IDT). First, to consider the power flow angles of SH-SAWs and R-SAWs on this substrate, the 360-MHz delay lines with six different tilt angles were designed and fabricated. From the experiments, an optimal power flow angle of 9° for the SH-SAW on this substrate is obtained. Second, in order to consider the immunoreactions of the SH-SAW immunosensors, a delay line with a tilt angle of 9° was designed and fabricated on this substrate. The delay line, which can generate two SAWs, namely, a 100-MHz SH-SAW and an 88.8-MHz R-SAW, has a propagation area covered with antigens of human serum albumin between transmitting and receiving IDTs. The immunoreactions caused by antigen-antibody binding events on the surface of the delay line were investigated on the basis of the velocity changes of the SH-SAWs for sensing with and without the assistance of an R-SAW. As a result, it was confirmed that the SH-SAW velocity changes due to antigen-antibody reactions can be markedly increased by the assistance of R-SAW agitation.

  18. Penetrate-leach dissolution of zirconium-clad uranium and uranium dioxide fuels

    International Nuclear Information System (INIS)

    Harmon, H.D.

    1975-01-01

    A new decladding-dissolution process was developed for zirconium-clad uranium metal and UO 2 fuels. The proposed penetrate-leach process consists of penetrating the zirconium cladding with Alniflex solution (2M HF--1M HNO 3 --1M Al(NO 3 ) 3 --0.1M K 2 Cr 2 O 7 ) and of leaching the exposed core with 10M HNO 3 . Undissolved cladding pieces are discarded as solid waste. Periodic HF and HNO 3 additions, efficient agitation, and in-line zirconium analyses are required for successful control of ZrF 4 and/or AlF 3 precipitation during the cladding-penetration step. Preliminary solvent extraction studies indicated complete recovery of uranium with 30 vol. percent tributyl phosphate (TBP) from both Alniflex solution and blended Alniflex-HNO 3 leach solutions. With 7.5 vol. percent TBP, high extractant/feed flow ratios and low scrub flows are required for satisfactory uranium recovery from Alniflex solution. Modified waste-handling procedures may be required for Alniflex waste, because it cannot be evaporated before neutralization and large quantities of solids are generated on neutralization. The effect of unstable UZr 3 (epsilon phase of uranium-zirconium system) on the safety of penetrate-leach dissolution was investigated

  19. Uranium and nuclear power

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    Basic principles and definitions of reactor technology, biological radiation effects in man, and radioactive wastes are outlined. An argument is presented against Australia exploiting its uranium resources. (R.L.)

  20. Uranium hexafluoride purification

    International Nuclear Information System (INIS)

    Araujo, Eneas F. de

    1986-01-01

    Uranium hexafluoride might contain a large amount of impurities after manufacturing or handling. Three usual methods of purification of uranium hexafluoride were presented: selective sorption, sublimation, and distillation. Since uranium hexafluoride usually is contaminated with hydrogen fluoride, a theoretical study of the phase equilibrium properties was performed for the binary system UF 6 -HF. A large deviation from the ideal solution behaviour was observed. A purification unity based on a constant reflux batch distillation process was developed. A procedure was established in order to design the re boiler, condenser and packed columns for the UF 6 -HF mixture separation. A bench scale facility for fractional distillation of uranium hexafluoride was described. Basic operations for that facility and results extracted from several batches were discussed. (author)

  1. Uranium dioxide pellets

    International Nuclear Information System (INIS)

    Zawidzki, T.W.

    1982-01-01

    A process for the preparation of a sintered, high density, large crystal grain size uranium dioxide pellet is described which involves: (i) reacting a uranyl nitrate of formula UO 2 (NO 3 ) 2 .6H 2 O with a sulphur source, at a temperature of from about 300 deg. C to provide a sulphur-containing uranium trioxide; (ii) reacting the thus-obtained modified uranium trioxide with ammonium nitrate to form an insoluble sulphur-containing ammonium uranate; (iii) neutralizing the thus-formed slurry with ammonium hydroxide to precipitate out as an insoluble ammonium uranate the remaining dissolved uranium; (iv) recovering the thus-formed precipitates in a dry state; (v) reducing the dry precipitate to UO 2 , and forming it into 'green' pellets; and (vi) sintering the pellets in a hydrogen atmosphere at an elevated temperature

  2. Uranium market activities

    International Nuclear Information System (INIS)

    Patterson, J.A.

    1975-01-01

    Results are summarized from the 1974 ERDA annual survey of buyers and sellers and from a survey of uranium price data which provided information on additional domestic buying activity during the first half of 1975 through 1982

  3. Heap leaching for uranium

    International Nuclear Information System (INIS)

    1988-01-01

    Denison Mines Ltd. is using two bacterial leaching processes to combat the high cost of extracting uranium from low grade ore in thin reefs. Both processes use thiobacillus ferro-oxidans, a bacterium that employs the oxidation of ferrous iron and sulphur as its source of energy for growth. The first method is flood leaching, in which ore is subjected to successive flood, drain and rest cycles. The second, trickle leaching, uses sprinklers to douse the broken muck continuously with leaching solution. In areas where grades are too low to justify the expense of hauling the ore to the surface, the company is using this biological process underground to recover uranium. In 1987 Denison recovered 840 000 lb of uranium through bacterial heap leaching. It plans to have biological in-place leaching contribute 25% of the total uranium production by 1990. (fig.)

  4. Uranium purchases report 1993

    International Nuclear Information System (INIS)

    1994-01-01

    Data reported by domestic nuclear utility companies in their responses to the 1991 through 1993 ''Uranium Industry Annual Survey,'' Form EIA-858, Schedule B,'' Uranium Marketing Activities,'' are provided in response to the requirements in the Energy Policy Act 1992. Appendix A contains an explanation of Form EIA-858 survey methodologies with emphasis on the processing of Schedule B data. Additional information published in this report not included in Uranium Purchases Report 1992, includes a new data table. Presented in Table 1 are US utility purchases of uranium and enrichment services by origin country. Also, this report contains additional purchase information covering average price and contract duration. Table 2 is an update of Table 1 and Table 3 is an update of Table 2 from the previous year's report. The report contains a glossary of terms

  5. Uranium in alkaline rocks

    International Nuclear Information System (INIS)

    Murphy, M.; Wollenberg, H.; Strisower, B.; Bowman, H.; Flexser, S.; Carmichael, I.

    1978-04-01

    Geologic and geochemical criteria were developed for the occurrence of economic uranium deposits in alkaline igneous rocks. A literature search, a limited chemical analytical program, and visits to three prominent alkaline-rock localities (Ilimaussaq, Greenland; Pocos de Caldas, Brazil; and Powderhorn, Colorado) were made to establish criteria to determine if a site had some uranium resource potential. From the literature, four alkaline-intrusive occurrences of differing character were identified as type-localities for uranium mineralization, and the important aspects of these localities were described. These characteristics were used to categorize and evaluate U.S. occurrences. The literature search disclosed 69 U.S. sites, encompassing nepheline syenite, alkaline granite, and carbonatite. It was possible to compare two-thirds of these sites to the type localities. A ranking system identified ten of the sites as most likely to have uranium resource potential

  6. Uranium in granites

    International Nuclear Information System (INIS)

    Maurice, Y.T.

    1982-01-01

    Recent research activities of the Canadian Uranium in Granites Study are presented in 18 papers and 3 abstracts. 'Granites' is used as a generic term for granitoids, granitic rocks, and plutonic rocks

  7. Uranium Research in Senegal

    International Nuclear Information System (INIS)

    Kanouté, Mamadou

    2015-01-01

    The work of mining companies have so far not proved economic uranium resources, but they have nevertheless contributed greatly to a better understanding of the geology, particularly in Eastern Senegal, on the upper Precambrian basin including which equivalents exist throughout West Africa (the uranium belt of Zaire) prospected by CEA-COGEMA teams. The researches carried out in Senegal, but also in Guinea and Mali helped establish a detailed map and understand the course of geological history. With new exploration techniques and data of airborne geophysical (radiometric) provided by the Mining Sector Support Programme (PASMI 9th EDF 9 ACP SE 09), AREVA, at the end of the first period validity of the exploration permit increased significantly, the resources. Prospects are favorable to a doubling of resources; objective of a uranium mine in Senegal. Synergies are possible and desirable with joint exploitation of uranium deposits located in Mali, near the border with Senegal.

  8. Uranium industry seminar

    International Nuclear Information System (INIS)

    1980-01-01

    The tenth annual Uranium Industry Seminar, sponsored by the US Department of Energy's (DOE) Grand Junction Office, was held in Grand Junction, Colorado, on October 22 and 23, 1980. There were 700 registered attendees as compared to 833 attending the previous year. The attendees were drawn largely from uranium and other energy resource companies, electric utility firms, energy consultants and service companies, and governmental agencies. In addition, there were representatives present from Indian tribes, universities, the media, DOE laboratories, and foreign countries and organizations. There were 14 papers presented at the seminar by speakers from the Department of Energy, US Geological Survey, and Bendix Field Engineering Corporation which is the on-site prime contractor for DOE's Grand Junction Office. The topics the papers dealt with were uranium policies, exploration, respources, supply, enrichment, and market conditions. There also were papers describing the National Uranium Resource Evaluation program and international activities. All 14 papers in this Proceedings have been abstracted and indexed

  9. Uranium in South Africa

    International Nuclear Information System (INIS)

    Ford, M.A.

    1993-01-01

    The history, sources, mineralogy, extraction metallurgy, conversion, and enrichment of uranium in South Africa is reviewed. Over the past 40 years extraction plants were built at 27 sites, and over 140 kt of uranium have been produced. Older plants have had to adapt to changing market conditions, no single technology has had the opportunity to become entrenched, and the costs have been reduced to a third of those of the original flowsheet. The research efforts aimed at developing the country's nuclear raw materials have been particularly rewarding, as they have enabled South Africa to become a world leader in the extraction of uranium from low-grade ores and to develop methods for uranium enrichment and the production of nuclear fuels. 43 refs., 7 figs., 4 tabs

  10. Ontario's uranium mining industry

    International Nuclear Information System (INIS)

    Runnalls, O.J.C.

    1981-01-01

    This report traces the Ontario uranium mining industry from the first discovery of uranium north of Sault Ste. Marie through the uranium boom of the 1950's when Elliot Lake and Bancroft were developed, the cutbacks of the 1960s, the renewed enthusiasm in exploration and development of the 1970s to the current position when continued production for the domestic market is assured. Ontario, with developed mines and operational expertise, will be in a position to compete for export markets as they reopen. The low level of expenditures for uranium exploration and the lack of new discoveries are noted. The report also reviews and places in perspective the development of policies and regulations governing the industry and the jurisdictional relationships of the Federal and Provincial governments

  11. Uranium dioxide. Sintering test

    International Nuclear Information System (INIS)

    Anon.

    Description of a sintering method and of the equipment devoted to uranium dioxide powder caracterization and comparison between different samples. Determination of the curve giving specific volume versus pressure and micrographic examination of a pellet at medium pressure [fr

  12. Uranium in alkaline rocks

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, M.; Wollenberg, H.; Strisower, B.; Bowman, H.; Flexser, S.; Carmichael, I.

    1978-04-01

    Geologic and geochemical criteria were developed for the occurrence of economic uranium deposits in alkaline igneous rocks. A literature search, a limited chemical analytical program, and visits to three prominent alkaline-rock localities (Ilimaussaq, Greenland; Pocos de Caldas, Brazil; and Powderhorn, Colorado) were made to establish criteria to determine if a site had some uranium resource potential. From the literature, four alkaline-intrusive occurrences of differing character were identified as type-localities for uranium mineralization, and the important aspects of these localities were described. These characteristics were used to categorize and evaluate U.S. occurrences. The literature search disclosed 69 U.S. sites, encompassing nepheline syenite, alkaline granite, and carbonatite. It was possible to compare two-thirds of these sites to the type localities. A ranking system identified ten of the sites as most likely to have uranium resource potential.

  13. The uranium market prospects

    International Nuclear Information System (INIS)

    Lloyd, R.

    1981-01-01

    A historical analysis of the uranium market points out the cyclical nature of the market and suggests that the spot price, exploration levels, and mill capacity utilization rate are dependent on economic factors. An examination of the current uranium market suggests that the effects of the forecasted surplus supply, the diminishing returns in exploration and the long lead times and high costs of development may mean that future production levels are uncertain. The general prospects for the uranium industry are also uncertain because of barriers to trade, environmental regulations and public opinion. The paper concludes that by the use of long term contracts, appropriate inventory policy and greater discussion between producers and consumers the prospects for the uranium market can be made more certain and further imbalances in demand and supply can be avoided. (author)

  14. Uranium industry seminar: proceedings

    International Nuclear Information System (INIS)

    1981-01-01

    The eleventh annual Uranium Industry Seminar, sponsored by the Grand Junction Area Office of the US Department of Energy (DOE), was held in Grand Junction, Colorado, on October 21 and 22, 1981. There were 491 registered attendees as compared to 700 attending the previous year. The attendees were largely from uranium and other energy resource companies, electric utility firms, energy consultants and service companies, and governmental agencies. In addition, there were representatives present from Indian tribes, universities, the media, DOE laboratories, and foreign countries and organizations. Papers presented at the seminar dealt with uranium policies, exploration, resources, supply, enrichment, and market conditions. There also were papers on the National Uranium Resource Evaluation Program and international activities. Thirteen papers included in this report have been abstracted and indexed

  15. Internal friction in uranium

    International Nuclear Information System (INIS)

    Selle, J.E.

    1975-01-01

    Results are presented of studies conducted to relate internal friction measurements in U to allotropic transformations. It was found that several internal friction peaks occur in α-uranium whose magnitude changed drastically after annealing in the β phase. All of the allotropic transformations in uranium are diffusional in nature under slow heating and cooling conditions. Creep at regions of high stress concentration appears to be responsible for high temperature internal friction in α-uranium. The activation energy for grain boundary relaxation in α-uranium was found to be 65.1 +- 4 kcal/mole. Impurity atoms interfere with the basic mechanism for grain boundary relaxation resulting in a distribution in activation energies. A considerable distribution in ln tau 0 was also found which is a measure of the distribution in local order and in the Debye frequency around a grain boundary

  16. Uranium Location Database

    Data.gov (United States)

    U.S. Environmental Protection Agency — A GIS compiled locational database in Microsoft Access of ~15,000 mines with uranium occurrence or production, primarily in the western United States. The metadata...

  17. Uranium - the plain facts

    International Nuclear Information System (INIS)

    Technical, political, environmental and sociological aspects are discussed under the headings: mining; milling; dangers (particularly, radiation hazards); human sacrifice; Namibia; future of uranium; what you can do. (U.K.)

  18. Uranium in Canada

    International Nuclear Information System (INIS)

    1989-01-01

    In 1988 Canada's five uranium producers reported output of concentrate containing a record 12,470 metric tons of uranium (tU), or about one third of total Western world production. Shipments exceeded 13,200 tU, valued at $Cdn 1.1 billion. Most of Canada's uranium output is available for export for peaceful purposes, as domestic requirements represent about 15 percent of production. The six uranium marketers signed new sales contracts for over 11,000 tU, mostly destined for the United States. Annual exports peaked in 1987 at 12,790 tU, falling back to 10,430 tU in 1988. Forward domestic and export contract commitments were more than 70,000 tU and 60,000 tU, respectively, as of early 1989. The uranium industry in Canada was restructured and consolidated by merger and acquisition, including the formation of Cameco. Three uranium projects were also advanced. The Athabasca Basin is the primary target for the discovery of high-grade low-cost uranium deposits. Discovery of new reserves in 1987 and 1988 did not fully replace the record output over the two-year period. The estimate of overall resources as of January 1989 was down by 4 percent from January 1987 to a total (measured, indicated and inferred) of 544,000 tU. Exploration expenditures reached $Cdn 37 million in 1987 and $59 million in 1988, due largely to the test mining programs at the Cigar Lake and Midwest projects in Saskatchewan. Spot market prices fell to all-time lows from 1987 to mid-1989, and there is little sign of relief. Canadian uranium production capability could fall below 12,000 tU before the late 1990s; however, should market conditions warrant output could be increased beyond 15,000 tU. Canada's known uranium resources are more than sufficient to meet the 30-year fuel requirements of those reactors in Canada that are now or are expected to be in service by the late 1990s. There is significant potential for discovering additional uranium resources. Canada's uranium production is equivalent, in

  19. U for uranium

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    The Beisa Mine is unique in South Africa - it is the only underground mine with uranium as its main product and gold as a by-product. At the rate of 1,2 Mt/a, the life of Beisa is estimated on 26 years. Beisa's metallurgical plant is designed to handle initially a monthly throughput of 100 000t of ore, from which uranium, gold and silver will be extracted

  20. Uranium leads political stakes

    International Nuclear Information System (INIS)

    James, D.

    2009-01-01

    Until the announcement by the federal Environment Minister Peter Garrett that the government would permit uranium mining at Beverly Four Mile, South Australia, there had been little news flow from the sector over the past year. Uranium was the first to turn down, even before the United States sub-prime mortgage crisis began to cause shock waves through the global economy, a report by BGF Equities analyst Warwick Grigor shows.

  1. Uranium purchases report 1994

    International Nuclear Information System (INIS)

    1995-07-01

    US utilities are required to report to the Secretary of Energy annually the country of origin and the seller of any uranium or enriched uranium purchased or imported into the US, as well as the country of origin and seller of any enrichment services purchased by the utility. This report compiles these data and also contains a glossary of terms and additional purchase information covering average price and contract duration. 3 tabs

  2. Gases in uranium exploration

    International Nuclear Information System (INIS)

    Wright, R.J.; Pacer, J.C.

    1981-01-01

    Interest continues to grow in the use of helium and radon detection as a uranium exploration tool because, in many instances, these radiogenic gases are the only indicators of deeply buried mineralization. The origin of these gases, their migration in the ground, the type of samples and measurement techniques are discussed. Case histories of comparative tests conducted on known uranium deposits at three geologically diverse sites in the United States of America are also presented. (author)

  3. Argentinian uranium production

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    A profit-making process for the exploitation of low grade uranium is presented. The process of lixiviation will be used, which will make it possible to obtain a final product whose humidity level will not exceed 10% and whose uranium oxide content will be no less than 68%. The operations of the plant are described. The plant can produce between 100 and 150 t of U 3 O 8 /yr in the form of yellow cake

  4. World uranium resources

    International Nuclear Information System (INIS)

    Deffeyes, K.S.; MacGregor, I.D.

    1980-01-01

    To estimate the total resource availability of uranium, the authors' approach has been to ask whether the distribution of uranium in the earth's crust can be reasonably approximated by a bell-shaped log-normal curve. In addition they have asked whether the uranium deposits actually mined appear to be a portion of the high-grade tail, or ascending slope, of the distribution. This approach preserves what they feel are the two most important guiding principles of Hubbert's work, for petroleum, namely recognizing the geological framework that contains the deposits of interest and examining the industry's historical record of discovering those deposits. Their findings, published recently in the form of a book-length report prepared for the US Department of Energy, suggest that for uranium the crustal-distribution model and the mining-history model can be brought together in a consistent picture. In brief, they conclude that both sets of data can be described by a single log-normal curve, the smoothly ascending slope of which indicates approximately a 300-fold increase in the amount of uranium recoverable for each tenfold decrease in ore grade. This conclusion has important implications for the future availability of uranium. They hasten to add, however, that this is only an approximative argument; no rigorous statistical basis exists for expecting a log-normal distribution. They continue, pointing out the enormously complex range of geochemical behavior of uranium - and its wide variety of different binds of economic deposit. Their case study, supported by US mining records, indicates that the supply of uranium will not be a limiting factor in the development of nuclear power

  5. Recovery of uranium values

    International Nuclear Information System (INIS)

    Rowden, G.A.

    1982-01-01

    A process is provided for the recovery of uranium from an organic extractant phase containing an amine. The extractant phase is contacted in a number of mixing stages with an acidic aqueous stripping phase containing sulphate ions, and the phases are passed together through a series of mixing stages while maintaining a dispersion of droplets of one phase in the other. Uranium is precipitated from the final stage by raising the pH. An apparatus having several mixing chambers is described

  6. Uranium - the nuclear fuel

    International Nuclear Information System (INIS)

    Smith, E.E.N.

    1976-01-01

    A brief history is presented of Canadian uranium exploration, production, and sales. Statistics show that Canada is a good customer for its own uranium due to a rapidly expanding nuclear power program. Due to an average 10 year lag between commencement of exploration and production, and with current producers sold out through 1985, it is imperative that exploration efforts be increased. (E.C.B.)

  7. Uranium project. Geochemistry prospection

    International Nuclear Information System (INIS)

    Lambert, J.

    1983-01-01

    Geochemistry studies the distribution of the chemicals elements in the terrestrial crust and its ways to migrate. The terminology used in this report is the following one: 1) Principles of the prospection geochemistry 2) Stages of the prospection geochemistry 3)utility of the prospection geochemistry 4) geochemistry of uranium 5) procedures used within the framework of uranium project 6) Average available 7) Selection of the zones of prospection geochemistry 8) Stages of the prospection, Sample preparation and analisis 9) Presentation of the results

  8. Worldwide developments in uranium

    International Nuclear Information System (INIS)

    Hoellen, E.E.

    1987-01-01

    World uranium production will continue to change in most major producing nations. Canadian production will increase and will be increasingly dominated by western producers as eastern Canadian high-cost production declines. Australian production will increase as major projects come into operation before 2000. US production will stabilize through the end of the century. South African production will be dependent upon the worldwide support for economic sanctions. China's entry into the world market injects yet another variable into the already cloudy supply picture. Many risks and uncertainties will face uranium producers through the 1980s. Recognizing that the uranium industry is not a fast-growing market, many existing and potential producers are seeking alternate investment courses, causing a restructuring of the world uranium production industry in ways not anticipated even a few years ago. During the restructuring process, world uranium production will most likely continue to exceed uranium consumption, resulting in a further buildup of world uranium inventories. Inventory sales will continue to redistribute this material. As inventory selling runs its course, users will turn to normal sources of supply, stimulating additional production to meet needs. Stimulation in the form of higher prices will be determined by how fast producers are willing and able to return to the market. Production costs are expected to have an increasing impact as it has become apparent that uranium resources are large in comparison to projected consumption. Conversely, security-of-supply issues have seemed to be of decreasing magnitude as Canada, Australia, and other non-US producers continue to meet delivery commitments

  9. Uranium tailings bibliography

    International Nuclear Information System (INIS)

    Holoway, C.F.; Goldsmith, W.A.; Eldridge, V.M.

    1975-12-01

    A bibliography containing 1,212 references is presented with its focus on the general problem of reducing human exposure to the radionuclides contained in the tailings from the milling of uranium ore. The references are divided into seven broad categories: uranium tailings pile (problems and perspectives), standards and philosophy, etiology of radiation effects, internal dosimetry and metabolism, environmental transport, background sources of tailings radionuclides, and large-area decontamination

  10. Saskatchewan resources. [including uranium

    Energy Technology Data Exchange (ETDEWEB)

    1979-09-01

    The production of chemicals and minerals for the chemical industry in Saskatchewan are featured, with some discussion of resource taxation. The commodities mentioned include potash, fatty amines, uranium, heavy oil, sodium sulfate, chlorine, sodium hydroxide, sodium chlorate and bentonite. Following the successful outcome of the Cluff Lake inquiry, the uranium industry is booming. Some developments and production figures for Gulf Minerals, Amok, Cenex and Eldorado are mentioned.

  11. Ranger uranium environmental enquiry

    International Nuclear Information System (INIS)

    1976-07-01

    The submission is divided into three sections. Section A considers the international implications of the development of uranium resources including economic and resource aspects and environmental and social aspects. Section B outlines the government's position on export controls over uranium and its effect on the introduction of nuclear power in Australia. Section C describes the licensing and regulatory functions that would be needed to monitor the environmental and health aspects of the Ranger project. (R.L.)

  12. Uranium determination in water

    International Nuclear Information System (INIS)

    Prudenzo, E.J.; Puga, Maria J.; Cerchietti, Maria L.R.; Arguelles, Maria G.

    2005-01-01

    In our laboratory, a procedure has been assessed to determine uranium content of water in normal situations. The method proposed without sample pre-treatment, is simple and rapid. Uranium mass is measured by fluorimetry. For calculation of detection limit (Ld) and quantification level (Lq) we used blank samples and the results were analyzed for different statistical test. The calculation of total propagated uncertainty and sources contribution on real samples are presented. (author)

  13. US uranium market developments

    International Nuclear Information System (INIS)

    Krusiewski, S.V.; Thomas, D.C.

    1981-01-01

    Domestic uranium delivery commitments for the 1981 to 1990 period reached a peak in the July 1980 survey and then declined in the January 1981 survey and again in the July 1981 survey. However, there are sizable sales contracts through the mid-1980s. In the latter part of this decade, unfilled requirements increase which can provide a needed market for domestic producers. Older contracts are helping to keep the average contract prices, including market price settlements, rather stable. However, average market price settlements decreased from data reported in January 1981, but some of these deliveries represent settlement of litigation. Foreign uranium procurement is scheduled to exceed deliveries of US uranium to foreign buyers in the 1981 to 1990 period. However, the actual use of foreign uranium has been quite low as US enrichment services customers have preferred to buy US uranium. Based on over four and one-half years of data, only about 7% foreign uranium has been brought to the Department of Energy for enrichment. Inventories of natural and enriched uranium in buyers' hands continue to increase. This is a concern to the uranium-producing industry. However, the industry should not be concerned about DOE-owned inventories, which are needed to supply Government requirements. There is absolutely no plan to dispose of DOE inventories on the commercial market. Capital expenditures reached a peak of $800 million in 1979. This decreased to $780 million in 1980, although higher expenditures were planned for the year. A very sharp reduction in plans for 1981, from $830 to $450 million, has been reported. A further reduction to $350 million is planned for 1982. However, it is interesting to note that the planned expenditures for 1982 are above the expenditures for 1975, a period of industury expansion

  14. URANIUM SEPARATION PROCESS

    Science.gov (United States)

    Lyon, W.L.

    1962-04-17

    A method of separating uranium oxides from PuO/sub 2/, ThO/sub 2/, and other actinide oxides is described. The oxide mixture is suspended in a fused salt melt and a chlorinating agent such as chlorine gas or phosgene is sparged through the suspension. Uranium oxides are selectively chlorinated and dissolve in the melt, which may then be filtered to remove the unchlorinated oxides of the other actinides. (AEC)

  15. A novel photoelectrochemical immunosensor by integration of nanobody and ZnO nanorods for sensitive detection of nucleoside diphosphatase kinase-A

    International Nuclear Information System (INIS)

    Liu, Anran; Yin, Kaifei; Mi, Li; Ma, Mengyao; Liu, Yuanjian; Li, Ying; Wei, Wei; Zhang, Yuanjian; Liu, Songqin

    2017-01-01

    Nucleoside diphosphatase kinase A (NDPK-A) is a metastasis-suppressor protein and a biomarker that act on a wide range cancer cells to inhibit the potential metastasis. Herein, we present a simple photoelectrochemical immunosensor based on ZnO nanorod arrays for the sensitive detection of NDPK-A. The ZnO nanorod arrays cosensitized with CdS nanoparticles and Mn 2+ displayed a high and stable photocurrent response under irradiation. After anti-NPDK-A nanobodies were immobilized to the ZnO nanorod arrays, the proposed immunosensor can be utilized for detecting NPDK-A by monitoring the changes in the photocurrent signals of the electrode resulting from immunoreaction. Accordingly, the well-designed immunosensor exhibited a low limit of detection (LOD) of 0.3 pg mL −1 and a wide linear range from 0.5 pg mL −1 to 10 μg mL −1 . The R 2 of the regression curve is 0.99782. Meanwhile, the good stability, reproducibility and specificity of the resulting photoelectrochemical biosensor are demonstrated. In addition, the presented work would offer a novel and simple approach for the detection of immunoreactions and provide new insights in popularizing the diagnosis of NPDK-A. - Highlights: • A photoelectrochemical immunosensor based on ZnO NAs and NBs was fabricated. • Cosensitized structure of ZnO NAs, CdS and Mn improved the photocurrent response. • An excellent sensitivity and selectivity of NDPK-A detection was obtained.

  16. A label-free electrochemical immunosensor based on the novel signal amplification system of AuPdCu ternary nanoparticles functionalized polymer nanospheres.

    Science.gov (United States)

    Yan, Qin; Yang, Yuying; Tan, Zhaoling; Liu, Qing; Liu, Hui; Wang, Ping; Chen, Lei; Zhang, Daopeng; Li, Yueyun; Dong, Yunhui

    2018-04-30

    A sensitive label-free electrochemical immunosensor was designed using a novel signal amplification system for quantitative detecting hepatitis B surface antigen (HBsAg). Nitrogen-doped graphene quantum dots (N-GQDs) supported surfactant-free AuPdCu ternary nanoparticles (AuPdCu/N-GQDs), which featured with good conductivity and excellent catalytic properties for the reduction of hydrogen peroxide (H 2 O 2 ), was synthesized by a simple and benign hydrothermal procedure. At the same time, the electroactive polymer nanospheres (PS) was synthesized by infinite coordination polymers of ferrocenedicarboxylic acid, which could play as carrier and electronic mediator to load AuPdCu/N-GQDs. The PS not only improved the ability to load antibodies because of the good biocompatibility, but also accelerated electron transport of the electrode interface attribute to plentiful ferrocene unit. Thus, the prepared AuPdCu/N-GQDs@PS has abilities of good biocompatibility, catalytic activity and electrical conductivity to be applied as transducing materials to amplify electrochemical signal in detection of HBsAg. Under optimal conditions, the fabricated immunosensor exhibited high sensitivity and stability in the detection of HBsAg. A linear relationship between current signals and the concentrations of HBsAg was obtained in the range from 10fg/mL to 50ng/mL and the detection limit of HBsAg was 3.3fg/mL (signal-to-noise ratio of 3). Moreover, the designed immunosensor with excellent selectivity, reproducibility and stability shows excellent performance in detection of human serum samples. Furthermore, this label-free electrochemical immunosensor has promising application in clinical diagnosis of HBsAg. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. A novel photoelectrochemical immunosensor by integration of nanobody and ZnO nanorods for sensitive detection of nucleoside diphosphatase kinase-A

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Anran, E-mail: liuar@seu.edu.cn; Yin, Kaifei; Mi, Li; Ma, Mengyao; Liu, Yuanjian; Li, Ying; Wei, Wei; Zhang, Yuanjian; Liu, Songqin

    2017-06-22

    Nucleoside diphosphatase kinase A (NDPK-A) is a metastasis-suppressor protein and a biomarker that act on a wide range cancer cells to inhibit the potential metastasis. Herein, we present a simple photoelectrochemical immunosensor based on ZnO nanorod arrays for the sensitive detection of NDPK-A. The ZnO nanorod arrays cosensitized with CdS nanoparticles and Mn{sup 2+} displayed a high and stable photocurrent response under irradiation. After anti-NPDK-A nanobodies were immobilized to the ZnO nanorod arrays, the proposed immunosensor can be utilized for detecting NPDK-A by monitoring the changes in the photocurrent signals of the electrode resulting from immunoreaction. Accordingly, the well-designed immunosensor exhibited a low limit of detection (LOD) of 0.3 pg mL{sup −1} and a wide linear range from 0.5 pg mL{sup −1} to 10 μg mL{sup −1}. The R{sup 2} of the regression curve is 0.99782. Meanwhile, the good stability, reproducibility and specificity of the resulting photoelectrochemical biosensor are demonstrated. In addition, the presented work would offer a novel and simple approach for the detection of immunoreactions and provide new insights in popularizing the diagnosis of NPDK-A. - Highlights: • A photoelectrochemical immunosensor based on ZnO NAs and NBs was fabricated. • Cosensitized structure of ZnO NAs, CdS and Mn improved the photocurrent response. • An excellent sensitivity and selectivity of NDPK-A detection was obtained.

  18. Electrochemical immunosensor for the milk allergen β-lactoglobulin based on electrografting of organic film on graphene modified screen-printed carbon electrodes.

    Science.gov (United States)

    Eissa, Shimaa; Tlili, Chaker; L'Hocine, Lamia; Zourob, Mohammed

    2012-01-01

    A novel label-free voltammetric immunosensor for sensitive detection of β-lactoglobulin using graphene modified screen printed electrodes has been developed. The derivatization of the graphene electrode surface was achieved by electrochemical reduction of in situ generated 4-nitrophenyl diazonium cations in aqueous acidic solution, followed by electrochemical reduction of the terminal nitro groups to amines. The electrochemical modification protocol was optimized in order to generate monolayer of nitrophenyl groups on the graphene surface without complete passivation of the electrode. Unlike the reported method for graphene functionalization, we demonstrated here the ability of the electrografting of aryl diazonium salt to attach an organic film to the graphene surface in a controlled manner by choosing the suitable grafting protocol. Next, the amine groups on the graphene surface were activated using glutaraldehyde and used for the covalent immobilization of β-lactoglobulin antibodies. Cyclic and differential pulse voltammetry carried out in an aqueous solution containing [Fe(CN)(6)](3-/4-) redox pair have been used for the immunosensor characterization. The results demonstrated that the DPV reduction peak current of [Fe(CN)(6)](3-/4-) decreased linearly with increasing the concentration of β-lactoglobulin due to the formation of antibody-antigen complex on the modified electrode surface. The immunosensor obtained using this novel approach enabled a detection limit of 0.85 pg mL(-1) and a dynamic range from 1 pg mL(-1) to 100 ng mL(-1) of β-lactoglobulin in PBS buffer. In addition, the immunosensor evaluated in different samples including cake, cheese snacks, a sweet biscuit, showing excellent correlation with the results obtained from commercially enzyme-linked immunosorbent assay (ELISA) method. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Nanoparticle-Based Electrochemical Immunosensor for the Detection of Phosphorylated Acetylcholinesterase: An Exposure Biomarker of Organophosphate Pesticides and Nerve AgentsOrganophosphate Pesticides and Nerve Agents

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Guodong; Wang, Jun; Barry, Richard C.; Petersen, Catherine E.; Timchalk, Charles; Gassman, Paul L.; Lin, Yuehe

    2008-11-01

    A nanoparticle-based electrochemical immunosensor has been developed for the detection of phosphorylated acetylcholinesterase (AChE) adducts, which is a potential exposure biomarker for organophosphate pesticides (OP) and chemical warfare nerve agent exposures. Zirconia nanoparticles (ZrO2 NPs) were used as selective sorbents to capture the phosphorylated AChE adduct, and quantum dots (ZnS@CdS, QDs) were used as tags to label monoclonal anti-AChE antibody to track the immunorecognition events. The sandwich-like immunoreactions were performed among the ZrO2 NPs, which were pre-coated on a screen printed electrode (SPE) by electrodeposition, phosphorylated AChE and QD-anti-AChE. The captured QD tags were determined on the SPE by electrochemical stripping analysis of its metallic component (cadmium) after an acid-dissolution step. Paraoxon was used as a model OP insecticide to prepare the phosphorylated AChE adduct to demonstrate the proof of principle for this sensor technology. The paraoxon-AChE adduct was characterized by Fourier Transform Infrared Spectrum, and the binding affinity of anti-AChE to the paraoxon-AChE was validated with an enzyme-linked immunosorbent assay. The parameters (e.g., amount of ZrO2 NP, QD-anti-AChE concentration,) that govern the electrochemical response of immunosensors were optimized. The voltammetric response of the immunosensor is highly linear over the range of 10 pM to 4 nM paraoxon-AChE, and the limit of detection is estimated to be 8 pM. This new nanoparticle-based electrochemical immunosensor thus provides a sensitive and quantitative tool for biomonitoring exposure to OP pesticides and nerve agents.

  20. Uranium production in Sweden

    International Nuclear Information System (INIS)

    Bergh, S.

    1994-01-01

    The history of uranium production in Sweden is reviewed in the article. The World War II led to an exploitation of the Swedish alum shale on a large scale. In the last phase of the war it also became obvious that the shale might be used for energy production of quite another kind than oil. In 1947 AB Atom energy was founded, an enterprise with one of its purposes to extract uranium for peaceful use. A plant with a yearly capacity of 120 tons of uranium was erected at Ranstad and ready for production by 1965. From the start in Ranstad and for many years to come there was hardly any interest in an immediate large uranium production. It was decided to use the plant for studies on its more effective exploitation in case of an expansion in the future, bearing in mind the reactor programme. In the course of time economical reasons began to speak against the project. The shale seemed to have a future neither as oil nor as uranium resource. The complete termination of the work on uranium production from shale occurred in 1989

  1. Uranium control in phosphogypsum

    International Nuclear Information System (INIS)

    Hurst, F.J.; Arnold, W.D.

    1980-01-01

    In wet-process phosphoric acid plants, both previous and recent test results show that uranium dissolution from phosphate rock is significantly higher when the rock is acidulated under oxidizing conditions than under reducing conditions. Excess sulfate and excess fluoride further enhance the distribution of uranium to the cake. Apparently the U(IV) present in the crystal lattice of the apatite plus that formed by reduction of U(IV) by FE(II) during acidulation is trapped or carried into the crystal lattice of the calcium sulfate crystals as they form and grow. The amount of uranium that distributes to hemihydrate filter cake is up to seven times higher than the amount that distributes to the dihydrate cake. About 60% of the uranium in hemihydrate cakes can be readily leached after hydration of the cake, but the residual uranium (20 to 30%) is very difficult to remove economically. Much additional research is needed to develop methods for minimizing uranium losses to calcium filter cakes

  2. Automated uranium titration system

    International Nuclear Information System (INIS)

    Takahashi, M.; Kato, Y.

    1983-01-01

    An automated titration system based on the Davies-Gray method has been developed for accurate determination of uranium. The system consists of a potentiometric titrator with precise burettes, a sample changer, an electronic balance and a desk-top computer with a printer. Fifty-five titration vessels are loaded in the sample changer. The first three contain the standard solution for standardizing potassium dichromate titrant, and the next two and the last two contain the control samples for data quality assurance. The other forty-eight measurements are carried out for sixteen unknown samples. Sample solution containing about 100 mg uranium is taken in a titration vessel. At the pretreatment position, uranium (VI) is reduced to uranium (IV) by iron (II). After the valency adjustment, the vessel is transferred to the titration position. The rate of titrant addition is automatically controlled to be slower near the end-point. The last figure (0.01 mL) of the equivalent titrant volume for uranium is calculated from the potential change. The results obtained with this system on 100 mg uranium gave a precision of 0.2% (RSD,n=3) and an accuracy of better than 0.1%. Fifty-five titrations are accomplished in 10 hours. (author)

  3. Analytical method of uranium (IV) and uranium (VI) in uranium ores and uranium-bearing rocks

    International Nuclear Information System (INIS)

    Shen Zhuqin; Zheng Yongfeng; Li Qingzhen; Zhong Miaolan; Gu Dingxiang

    1995-11-01

    The best conditions for keeping the original valences of uranium during the dissolution and separation procedure of geological samples (especially those micro uranium-bearing rock) were studied. With the exist of high concentration protectants, the sample was decomposed with concentration HF at 40 +- 5 degree C. The U(VI) was dissolved completely and formed stable complex UO 2 F 2 , the U(IV) was precipitated rapidly and carried by carrier. Quantitative separation was carried out immediately with suction. The decomposition of sample and separation of solid/liquid phases was completed within two minutes. After separation, the U(IV) and U(VI) were determined quantitatively with laser fluorescence or voltametry respectively according to the uranium content. The limit of detection for this method is 0.7 μg/g, RSD is 10.5%, the determinate range of uranium is 2 x 10 -6 ∼10 -1 g/g. The uranium contents and their valence state ratio were measured for more than one hundred samples of sand stone and granite, the accuracy and precision of these results are satisfactory for uranium geological research. (12 tabs.; 11 refs.)

  4. Production of uranium peroxide

    International Nuclear Information System (INIS)

    Caropreso, F.E.; Kreuz, D.F.

    1977-01-01

    A process is claimed of recovering uranium values as uranium peroxide from an aqueous uranyl solution containing dissolved vanadium and sodium impurities by treating the uranyl solution with hydrogen peroxide in an amount sufficient to have an excess of at least 0.5 parts H 2 O 2 per part of vanadium (V 2 O 5 ) above the stoichiometric amount required to form the uranium peroxide, the hydrogen peroxide treatment is carried out in three sequential phases consisting of I, a precipitation phase in which the hydrogen peroxide is added to the uranyl solution to precipitate the uranium peroxide and the pH of the reaction medium maintained in the range of 2.5 to 5.5 for a period of from about 1 to 60 minutes after the hydrogen peroxide addition; II, a digestion phase in which the pH of the reaction medium is maintained in the range of 3.0 to 7.0 for a period of about 5 to 180 minutes and III, a final phase in which the pH of the reaction medium is maintained in the range of 4.0 to 7.0 for a period of about 1 to 60 minutes during which time the uranium peroxide is separated from the reaction solution containing the dissolved vanadium and sodium impurities. The excess hydrogen peroxide is maintained during the entire treatment up until the uranium peroxide is separated from the reaction medium

  5. The Streltsovskoye uranium district

    International Nuclear Information System (INIS)

    Ischukova, L.P.

    1997-01-01

    This paper describes the geology of the Streltsovskoye uranium district located in south-eastern Zabaikalie region, Chita Province, Siberia, Russia. This district hosts Russia's only currently active uranium production centre. The uranium ore was discovered from 1963 to 1967 by drilling below fluorite veins which had minor associated uranium mineralization and radioactive anomalies. The uranium occurs as large scale vein stockwork deposits of hydrothermal origin within a volcano-tectonic caldera formed by continental volcanism of Late Mesozoic age. Rocks occurring in the caldera include basalt and trachydacite, overlain by rhyolite, and with associated interbedded sediments. The ore bodies occur in steeply dipping faults, with the greatest concentrations located where faults along the margins of the caldera intersect steeply dipping, cross cutting, northeasterly and northwesterly striking faults. The Streltsovskoye caldera extends over an area of 150 km 2 and is underlain by a large batholith. The 19 identified uranium deposits occurred in structural features that cut through the caldera sequence and extend into the basement rocks. The caldera has a maximum thickness of 1400 metres. Details of several deposits are given, including descriptions of mineralization and associated alteration. (author). 10 figs

  6. Uranium-scintillator device

    International Nuclear Information System (INIS)

    Smith, S.D.

    1979-01-01

    The calorimeter subgroup of the 1977 ISABELLE Summer Workshop strongly recommended investigation of the uranium-scintillator device because of its several attractive features: (1) increased resolution for hadronic energy, (2) fast time response, (3) high density (i.e., 16 cm of calorimeter per interaction length), and, in comparison with uranium--liquid argon detectors, (4) ease of construction, (5) simple electronics, and (6) lower cost. The AFM group at the CERN ISR became interested in such a calorimeter for substantially the same reasons, and in the fall of 1977 carried out tests on a uranium-scintillator (U-Sc) calorimeter with the same uranium plates used in their 1974 studies of the uranium--liquid argon (U-LA) calorimeter. The chief disadvantage of the scintillator test was that the uranium plates were too small to fully contain the hadronic showers. However, since the scintillator and liquid argon tests were made with the plates, direct comparison of the two types of devices could be made

  7. A novel electrochemical immunosensor using β-cyclodextrins functionalized silver supported adamantine-modified glucose oxidase as labels for ultrasensitive detection of alpha-fetoprotein.

    Science.gov (United States)

    Gao, Jian; Ma, Hongmin; Lv, Xiaohui; Yan, Tao; Li, Na; Cao, Wei; Wei, Qin

    2015-09-17

    In this work, a novel sandwich-type electrochemical immunosensor based on host-guest interaction was fabricated for the detection of alpha-fetoprotein (AFP). Due to the large specific surface area of multiwalled carbon nanotubes and the unique supramolecular recognition ability of β-cyclodextrins, ferrocenecarboxylic acid (Fc) was incorporated into this sensor platform by host-guest interaction to generate an electrochemical signal. And β-cyclodextrins functionalized silver supported adamantine-modified glucose oxidase (GOD-CD-Ag), was used as a label to improve the analytical performance of the immunosensor by the dual amplification strategy. The obtained GOD-CD-Ag conjugates could convert glucose into gluconic acid with the formation of hydrogen peroxide (H2O2). And then silver nanoparticles could in situ catalyze the reduction of the generated H2O2, dramatically improving the oxidation reaction of Fc. The developed immunosensor shows a wide linear calibration range from 0.001 to 5.0 ng/mL with a low detection limit (0.2 pg/mL) for the detection of AFP. The method, with ideal reproducibility and selectivity, has a wide application prospect in clinical research. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. A sensitive electrochemical immunosensor based on poly(2-aminobenzylamine) film modified screen-printed carbon electrode for label-free detection of human immunoglobulin G.

    Science.gov (United States)

    Putnin, Thitirat; Jumpathong, Watthanachai; Laocharoensuk, Rawiwan; Jakmunee, Jaroon; Ounnunkad, Kontad

    2018-08-01

    This work focuses on fabricating poly(2-aminobenzylamine)-modified screen-printed carbon electrode as an electrochemical immunosensor for the label-free detection of human immunoglobulin G. To selectively detect immunoglobulin G, the anti-immunoglobulin G antibody with high affinity to immunoglobulin G was covalently linked with the amine group of poly(2-aminobenzylamine) film-deposited screen-printed carbon electrode. The selectivity for immunoglobulin G was subsequently assured by being challenged with redox-active interferences and adventitious adsorption did not significantly interfere the analyte signal. To obviate the use of costly secondary antibody, the [Fe(CN) 6 ] 4-/3- redox probe was instead applied to measure the number of human immunoglobulin G through the immunocomplex formation that is quantitatively related to the level of the differential pulse voltammetric current. The resulting immunosensor exhibited good sensitivity with the detection limit of 0.15 ng mL -1 , limit of quantitation of 0.50 ng mL -1 and the linear range from 1.0 to 50 ng mL -1 . Given those striking analytical performances and the affordability arising from using cheap screen-printed carbon electrode with label-free detection, the immunosensor serves as a promising model for the next-step development of a diagnostic tool.

  9. An Electrochemical Immunosensor for Detection of Staphylococcus aureus Bacteria Based on Immobilization of Antibodies on Self-Assembled Monolayers-Functionalized Gold Electrode

    Directory of Open Access Journals (Sweden)

    Abderrazak Maaref

    2012-10-01

    Full Text Available The detection of pathogenic bacteria remains a challenge for the struggle against biological weapons, nosocomial diseases, and for food safety. In this research, our aim was to develop an easy-to-use electrochemical immunosensor for the detection of pathogenic Staphylococcus aureus ATCC25923. The biosensor was elaborated by the immobilization of anti-S. aureus antibodies using a self-assembled monolayer (SAMs of 3-Mercaptopropionic acid (MPA. These molecular assemblies were spontaneously formed by the immersion of the substrate in an organic solvent containing the SAMs that can covalently bond to the gold surface. The functionalization of the immunosensor was characterized using two electrochemical techniques: cyclic voltammetry (CV and electrochemical impedance spectroscopy (EIS. Here, the analysis was performed in phosphate buffer with ferro/ferricyanide as the redox probe. The EIS technique was used for affinity assays: antibody-cell binding. A linear relationship between the increment in the electron transfer resistance (RCT and the logarithmic value of S. aureus concentration was observed between 10 and 106 CFU/mL. The limit of detection (LOD was observed at 10 CFU/mL, and the reproducibility was calculated to 8%. Finally, a good selectivity versus E. coli and S. epidermidis was obtained for our developed immunosensor demonstrating its specificity towards only S. aureus.

  10. Electrochemical immunosensor for the determination of insulin-like growth factor-1 using electrodes modified with carbon nanotubes-poly(pyrrole propionic acid) hybrids.

    Science.gov (United States)

    Serafín, V; Agüí, L; Yáñez-Sedeño, P; Pingarrón, J M

    2014-02-15

    An amperometric immunosensor for the determination of the hormone insulin-like growth factor 1 (IGF1) is reported for the first time in this work. As electrochemical transducer, a multiwalled carbon nanotubes-modified glassy carbon electrode on which poly(pyrrole propionic acid) was electropolymerized was prepared. This approach provided a high content of surface confined carboxyl groups suitable for direct covalent binding of anti-IGF1 monoclonal antibody. A sandwich-type immunoassay using a polyclonal antibody labeled with peroxidase, hydrogen peroxide as the enzyme substrate and catechol as redox mediator was employed to monitor the affinity reaction. All the variables involved in the preparation of the modified electrode were optimized and the electrodes were characterized by electrochemical impedance spectroscopy and cyclic voltammetry. Moreover, the different experimental variables affecting the amperometric response of the immunosensor were also optimized. The calibration graph for IGF1 showed a range of linearity extending from 0.5 to 1000 pg/mL, with a detection limit, 0.25 pg/mL, more than 100 times lower than the lowest values reported for the ELISA immunoassays available for IGF1 (30 pg/mL, approximately). Excellent reproducibility for the measurements carried out with different immunosensors and selectivity against other hormones were also evidenced. A commercial human serum spiked with IGF1 at different levels between 0.01 and 10.0 ng/mL was analyzed with good results. © 2013 Elsevier B.V. All rights reserved.

  11. Fabrication of a Novel Highly Sensitive and Selective Immunosensor for Botulinum Neurotoxin Serotype A Based on an Effective Platform of Electrosynthesized Gold Nanodendrites/Chitosan Nanoparticles

    Directory of Open Access Journals (Sweden)

    Rahim Sorouri

    2017-05-01

    Full Text Available In this work, a novel nanocomposite consisting of electrosynthesized gold nanodendrites and chitosan nanoparticles (AuNDs/CSNPs has been prepared to fabricate an impedimetric immunosensor based on a screen printed carbon electrode (SPCE for the rapid and sensitive immunoassay of botulinum neurotoxin A (BoNT/A. BoNT/A polyclonal antibody was immobilized on the nanocomposite-modified SPCE for the signal amplification. The structure of the prepared nanocomposite was investigated by transmission electron microscopy (TEM, scanning electron microscopy (SEM, X-ray diffraction (XRD, Fourier transform infrared (FTIR spectroscopy, cyclic voltammetry (CV, and electrochemical impedance spectroscopy (EIS. The charge transfer resistance (RCT changes were used to detect BoNT/A as the specific immuno-interactions at the immunosensor surface that efficiently limited the electron transfer of Fe(CN63−/4− as a redox probe at pH = 7.4. A linear relationship was observed between the %∆RCT and the concentration logarithm of BoNT/A within the range of 0.2 to 230 pg·mL−1 with a detection limit (S/N = 3 of 0.15 pg·mL−1. The practical applicability of the proposed sensor was examined by evaluating the detection of BoNT/A in milk and serum samples with satisfactory recoveries. Therefore, the prepared immunosensor holds great promise for the fast, simple and sensitive detection of BoNT/A in various real samples.

  12. Implementation of a SPR immunosensor for the simultaneous detection of the 22K and 20K hGH isoforms in human serum samples.

    Science.gov (United States)

    de Juan-Franco, Elena; Rodríguez-Frade, J M; Mellado, M; Lechuga, Laura M

    2013-09-30

    We have implemented a Surface Plasmon Resonance (SPR) immunosensor based on a sandwich assay for the simultaneous detection of the two main hGH isoforms, of 22 kDa (22K) and 20 kDa (20K). An oriented-antibody sensor surface specific for both hormone isoforms was assembled by using the biotin-streptavidin system. The immunosensor functionality was checked for the direct detection of the 22K hGH isoform in buffer, which gave high specificity and reproducibility (intra and inter-assay mean coefficients of variation of 8.23% and 9% respectively). The selective determination of the 22K and 20K hGH isoforms in human serum samples in a single assay was possible by using two specific anti-hGH monoclonal antibodies. The detection limit for both hormone isoforms was 0.9 ng mL(-1) and the mean coefficient of variation was below 7.2%. The excellent reproducibility and sensitivity obtained indicate the high performance of this immunosensor for implementing an anti-doping test. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Electrochemical immunosensor with NiAl-layered double hydroxide/graphene nanocomposites and hollow gold nanospheres double-assisted signal amplification.

    Science.gov (United States)

    Qiao, Lu; Guo, Yemin; Sun, Xia; Jiao, Yancui; Wang, Xiangyou

    2015-08-01

    A sensitive electrochemical immunosensor based on NiAl-layered double hydroxide/graphene nanocomposites (NiAl-LDH/G) and hollow gold nanospheres (HGNs) was proposed for chlorpyrifos detection. The NiAl-LDH/G was prepared using a conventional coprecipitation process and reduction of the supporting graphene oxide. Subsequently, the nanocomposites were dispersed with chitosan (CS). The NiAl-LDH/G possessed good electrochemical behavior and high binding affinity to the electrode. The high surface areas of HGNs and the vast aminos and hydroxyls of CS provided a platform for the covalently crosslinking of antibody. Under optimal conditions, the immunosensor exhibited a wide linear range from 5 to 150 μg/mL and from 150 to 2 μg/mL, with a detection limit of 0.052 ng/mL. The detection results showed good agreement with standard gas chromatography method. The constructed immunosensor exhibited good reproducibility, high specificity, acceptable stability and regeneration performance, which provided a new promising tool for chlorpyrifos detection in real samples.

  14. Study of uranium plating measurement

    International Nuclear Information System (INIS)

    Lin Jufang; Wen Zhongwei; Wang Mei; Wang Dalun; Liu Rong; Jiang Li; Lu Xinxin

    2007-06-01

    In neutron physics experiments, the measurement for plate-thickness of uranium can directly affect uncertainties of experiment results. To measure the plate-thickness of transform target (enriched uranium plating and depleted uranium plating), the back to back ionization chamber, small solid angle device and Au-Si surface barrier semi-conductor, were used in the experiment study. Also, the uncertainties in the experiment were analyzed. Because the inhomo-geneous of uranium lay of plate can quantitively affect the result, the homogeneity of uranium lay is checked, the experiment result reflects the homogeneity of uranium lay is good. (authors)

  15. Recovery of uranium by chlorination

    International Nuclear Information System (INIS)

    Komoto, Shigetoshi; Taki, Tomihiro

    1988-01-01

    The recovery of uranium from uraniferous phosphate by conventional process is generally uneconomic, except that uranium is recovered as a by-product. If an economical process by which uranium is recovered efficiently as a chief product is discovered, uraniferous phosphate will be used effectively as uranium ore. By using chiorination which will be expected to be favorable in comparison with conventional process, the recovery of uranium from uraniferous phosphate has been carried out. The paper describes the reaction machanism and general characteristics of the uranium chiorination, and the research done so for. (author)

  16. Anticorrosion protection of uranium

    Energy Technology Data Exchange (ETDEWEB)

    Goncharov, Ivan D.; Kazakovskaya, Tatiana; Tukmakov, Victor; Shapovalov, Vyacheslav [Russian Federal Nuclear Center-VNIIEF, 37, Mira Ave., RU-607190 Sarov (Nizhnii Gorod), 010450 (Russian Federation)

    2004-07-01

    Uranium in atmospheric conditions is non-stable. Sloughing products are being generated on its surface during storage or use. These corrosion products make many difficulties because of necessity to provide personnel safety. Besides, uranium corrosion may cause damage in parts. The first works devoted to uranium corrosion were performed in the framework of the USA Manhattan Project in the early forties of last century. Various methods of uranium protection were investigated, among them the galvanic one was the most studied. Later on the galvanic technology was patented. The works on this problem remains urgent up to the present time. In Russia, many methods of uranium corrosion protection, mainly against atmospheric corrosion, were tried on. In particular, such methods as diffusion zinc and paint coating were investigated. In the first case, a complex intermetallic U-Zn compound was formed but its protection was not reliable enough, this protection system was inconvenient and uncertain and that is why an additional paint coating was necessary. In the case of paint coatings another problem appeared. It was necessary to find such a coating where gas-permeability would prevail over water-permeability. Otherwise significant uranium corrosion occurs. This circumstance together with low mechanical resistance of paint coatings does not allow to use paint coating for long-term protection of uranium. Currently, there are following methods of uranium protection: ion-plasma, galvanic and thermo-vacuum annealing. These are described in this paper. In the end the issue of corrosion protection in reactor core zones is addressed. Here the greatest difficulties are caused when enriched uranium heated up to 500 deg. C needs anticorrosion protection. In this case various metal coatings are not reliable because of brittle inter-metallide formation. The reliable protection may be provided only up to the temperature plus 400 - 500 deg. C with the help of galvanic copper coating since

  17. Anticorrosion protection of uranium

    International Nuclear Information System (INIS)

    Goncharov, Ivan D.; Kazakovskaya, Tatiana; Tukmakov, Victor; Shapovalov, Vyacheslav

    2004-01-01

    Uranium in atmospheric conditions is non-stable. Sloughing products are being generated on its surface during storage or use. These corrosion products make many difficulties because of necessity to provide personnel safety. Besides, uranium corrosion may cause damage in parts. The first works devoted to uranium corrosion were performed in the framework of the USA Manhattan Project in the early forties of last century. Various methods of uranium protection were investigated, among them the galvanic one was the most studied. Later on the galvanic technology was patented. The works on this problem remains urgent up to the present time. In Russia, many methods of uranium corrosion protection, mainly against atmospheric corrosion, were tried on. In particular, such methods as diffusion zinc and paint coating were investigated. In the first case, a complex intermetallic U-Zn compound was formed but its protection was not reliable enough, this protection system was inconvenient and uncertain and that is why an additional paint coating was necessary. In the case of paint coatings another problem appeared. It was necessary to find such a coating where gas-permeability would prevail over water-permeability. Otherwise significant uranium corrosion occurs. This circumstance together with low mechanical resistance of paint coatings does not allow to use paint coating for long-term protection of uranium. Currently, there are following methods of uranium protection: ion-plasma, galvanic and thermo-vacuum annealing. These are described in this paper. In the end the issue of corrosion protection in reactor core zones is addressed. Here the greatest difficulties are caused when enriched uranium heated up to 500 deg. C needs anticorrosion protection. In this case various metal coatings are not reliable because of brittle inter-metallide formation. The reliable protection may be provided only up to the temperature plus 400 - 500 deg. C with the help of galvanic copper coating since

  18. Radiological impact assessment in Bagjata uranium deposit: a case study

    International Nuclear Information System (INIS)

    Sarangi, A.K.; Bhowmik, S.C.; Jha, V.N.

    2007-01-01

    The uranium ore mining facility, in addition to the desirable product, produces wastes in the form of environmental releases or effluents to air, water and soil. The toxicological and other (non-radiological) effects are generally addressed in EIA/EMP studies as per MOEF guidelines. Since the uranium ore is radioactive, it is desirable to conduct a study on radiological effects considering the impacts of radiological releases to the environment. Before undertaking the commercial mining operations at Bagjata uranium deposit in the Singhbhum east district of Jharkhand, pre-operational radiological base line data were generated and a separate study on radiological impact on various environmental matrices was conducted in line with the International Atomic Energy Agency's laid out guidelines. The paper describes the philosophy of such studies and the findings that helped in formulating a separate environmental management plan. (author)

  19. Oxidation of uranium and uranium alloys

    International Nuclear Information System (INIS)

    Orman, S.

    1976-01-01

    The corrosion behaviour of uranium in oxygen, water and water + oxygen mixtures is compared and contrasted. A considerable amount of work, much of it conflicting, has been published on the U + H 2 O and U + H 2 O + O 2 systems. An attempt has been made to summarise this data and to explain the reasons for the lack of agreement between the experimental results. The evidence for the mechanism involving OH - ion diffusion as the reacting entity in both the U + H 2 O and U + O 2 + H 2 O reactions is advanced. The more limited corrosion data on some lean uranium alloys and on some higher addition alloys referred to as stainless materials is summarised together with some previously unreported results obtained with these materials at AWRE. The data indicates that in the absence of oxygen the lean alloys behave in a similar manner to uranium and evolve hydrogen in approximately theoretical quantities. But the stainless alloys absorb most of the product hydrogen and assessments of reactivity based on hydrogen evolution would be very inaccurate. The direction that future corrosion work on these materials should take is recommended

  20. Process for electrolytically preparing uranium metal

    Science.gov (United States)

    Haas, Paul A.

    1989-01-01

    A process for making uranium metal from uranium oxide by first fluorinating uranium oxide to form uranium tetrafluoride and next electrolytically reducing the uranium tetrafluoride with a carbon anode to form uranium metal and CF.sub.4. The CF.sub.4 is reused in the fluorination reaction rather than being disposed of as a hazardous waste.

  1. Uranium exploration in Australia

    International Nuclear Information System (INIS)

    Battey, G.C.; Hawkins, B.W.

    1977-01-01

    As a result of exploration which recommenced in 1966 Australia's uranium reserves increased from 6,200 tonnes in 1967 to 227,000 tonnes uranium by June 1976. Most discoveries in the early 1950's were made by prospectors. The increase in reserves during the past decade is the result of exploration by companies utilising improved technology in areas selected as geologically favourable. These reserves were established at relatively low cost. In the Alligator Rivers Uranium Province the ''vein'' type deposits at Jabiluka, Ranger, Koongarra and Nabarlek contain 17% of the world's reserves. Most of these discoveries resulted from the investigation of airborne radiometric anomalies but cover over the prospective host rocks will necessitate the future use of costlier and more indirect exploration techniques. There was exploration for sandstone type uranium deposits in most of Australia's sedimentary basins. The greatest success was achieved in the Lake Frome Basin in South Australia. Other deposits were found in the Ngalia and Amadeus Basins in Central Australia and in the Westmoreland area, N.W. Queensland. A major uranium deposit was found in an unusual environment at Yeelirrie, Western Australia where carnotite occurs in a caliche and clay host which fills a shallow, ancient drainage channel. Although caliche occurrences are relatively widespread on the Precambrian shield no other economic deposit has been found. Recent discoveries in the Georgetown area of Queensland indicate the presence of another uranium province but it is too early to assess its potential. The ore occurs in clastic sediments at the base of a volcanic sequence overlying a Precambrian basement. Several companies which have established large uranium reserves have a number of additional attractive prospects. Exploration activity in Australia in 1975 was at a lower level than in previous years, but the potential for discovering further deposits is considered to be high

  2. Australia's uranium export potential

    International Nuclear Information System (INIS)

    Mosher, D.V.

    1981-01-01

    During the period 1954-71 in Australia approximately 9000 MT of U 3 O 8 was produced from five separate localities. Of this, 7000 MT was exported to the United Kingdom and United States and the balance stockpiled by the Australian Atomic Energy Commission (AAEC). Australia's uranium ore reserves occur in eight deposits in three states and the Northern Territory. However, 83% of Australia's reserves are contained in four deposits in lower Proterozoic rocks in the East Alligator River region of the Northern Territory. The AAEC has calculated Australia's recoverable uranium reserves by eliminating estimated losses during the mining and milling of the ores. AAEC has estimated reasonably assured resources of 289,000 MT of uranium at a recovery cost of less than US$80 per kilogram uranium. The companies have collectively announced a larger ore reserve than the Australian Atomic Energy Commission. This difference is a result of the companies adopting different ore reserve categories. On August 25, 1977, the federal government announced that Australia would develop its uranium resources subject to stringent environmental controls, recognition of Aboriginal Land Rights, and international safeguards. Australian uranium production should gradually increase from 1981 onward, growing to 10,000 to 15,000 MT by 1985-86. Further increases in capacity may emerge during the second half of the 1980s when expansion plans are implemented. Exploration for uranium has not been intensive due to delays in developing the existing deposits. It is likely that present reserves can be substantially upgraded if more exploration is carried out. 6 figures, 3 tables

  3. Influence of uranium hydride oxidation on uranium metal behaviour

    International Nuclear Information System (INIS)

    Patel, N.; Hambley, D.; Clarke, S.A.; Simpson, K.

    2013-01-01

    This work addresses concerns that the rapid, exothermic oxidation of active uranium hydride in air could stimulate an exothermic reaction (burning) involving any adjacent uranium metal, so as to increase the potential hazard arising from a hydride reaction. The effect of the thermal reaction of active uranium hydride, especially in contact with uranium metal, does not increase in proportion with hydride mass, particularly when considering large quantities of hydride. Whether uranium metal continues to burn in the long term is a function of the uranium metal and its surroundings. The source of the initial heat input to the uranium, if sufficient to cause ignition, is not important. Sustained burning of uranium requires the rate of heat generation to be sufficient to offset the total rate of heat loss so as to maintain an elevated temperature. For dense uranium, this is very difficult to achieve in naturally occurring circumstances. Areas of the uranium surface can lose heat but not generate heat. Heat can be lost by conduction, through contact with other materials, and by convection and radiation, e.g. from areas where the uranium surface is covered with a layer of oxidised material, such as burned-out hydride or from fuel cladding. These rates of heat loss are highly significant in relation to the rate of heat generation by sustained oxidation of uranium in air. Finite volume modelling has been used to examine the behaviour of a magnesium-clad uranium metal fuel element within a bottle surrounded by other un-bottled fuel elements. In the event that the bottle is breached, suddenly, in air, it can be concluded that the bulk uranium metal oxidation reaction will not reach a self-sustaining level and the mass of uranium oxidised will likely to be small in relation to mass of uranium hydride oxidised. (authors)

  4. Influence of uranium hydride oxidation on uranium metal behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Patel, N.; Hambley, D. [National Nuclear Laboratory (United Kingdom); Clarke, S.A. [Sellafield Ltd (United Kingdom); Simpson, K.

    2013-07-01

    This work addresses concerns that the rapid, exothermic oxidation of active uranium hydride in air could stimulate an exothermic reaction (burning) involving any adjacent uranium metal, so as to increase the potential hazard arising from a hydride reaction. The effect of the thermal reaction of active uranium hydride, especially in contact with uranium metal, does not increase in proportion with hydride mass, particularly when considering large quantities of hydride. Whether uranium metal continues to burn in the long term is a function of the uranium metal and its surroundings. The source of the initial heat input to the uranium, if sufficient to cause ignition, is not important. Sustained burning of uranium requires the rate of heat generation to be sufficient to offset the total rate of heat loss so as to maintain an elevated temperature. For dense uranium, this is very difficult to achieve in naturally occurring circumstances. Areas of the uranium surface can lose heat but not generate heat. Heat can be lost by conduction, through contact with other materials, and by convection and radiation, e.g. from areas where the uranium surface is covered with a layer of oxidised material, such as burned-out hydride or from fuel cladding. These rates of heat loss are highly significant in relation to the rate of heat generation by sustained oxidation of uranium in air. Finite volume modelling has been used to examine the behaviour of a magnesium-clad uranium metal fuel element within a bottle surrounded by other un-bottled fuel elements. In the event that the bottle is breached, suddenly, in air, it can be concluded that the bulk uranium metal oxidation reaction will not reach a self-sustaining level and the mass of uranium oxidised will likely to be small in relation to mass of uranium hydride oxidised. (authors)

  5. Uranium in Niger; L'uranium au Niger

    Energy Technology Data Exchange (ETDEWEB)

    Gabelmann, E

    1978-03-15

    This document presents government policy in the enhancement of uranium resources, existing mining companies and their productions, exploitation projects and economical outcome related to the uranium mining and auxiliary activities. [French] Le document presente la politique de l'Etat dans le cadre de la mise en valeur des ressources d'uranium, les societes minieres existantes et leurs productions, les projets d'exploitation d'uranium et les retombees economiques liees aux activites uraniferes et connexes.

  6. Pyrophoric behaviour of uranium hydride and uranium powders

    Science.gov (United States)

    Le Guyadec, F.; Génin, X.; Bayle, J. P.; Dugne, O.; Duhart-Barone, A.; Ablitzer, C.

    2010-01-01

    Thermal stability and spontaneous ignition conditions of uranium hydride and uranium metal fine powders have been studied and observed in an original and dedicated experimental device placed inside a glove box under flowing pure argon. Pure uranium hydride powder with low amount of oxide (Oxidation mechanisms are proposed.

  7. Uranium in phosphate rocks and future nuclear power fleets

    International Nuclear Information System (INIS)

    Gabriel, S.; Baschwitz, A.; Mathonniere, G.

    2014-01-01

    phosphoric acid. Uranium recovery as a by-product of phosphate rocks could be competitive for the moment, but limited at the most to 10 kt U per year, i.e. less than 20% of current world demand. The only way to lift the constraint of capacity production is to produce uranium as a primary product of phosphates. Unfortunately, this solution is very unlikely due to its high unit cost. In line with these considerations, the correspondence between the estimated resources and the forecast energy scenarios is examined, first with the current type of light water reactors which burn uranium, and secondly with a mixed fleet with both light water reactors and fast reactors which use plutonium. (author)

  8. Uranium Supply Strategy of China

    International Nuclear Information System (INIS)

    Gao Shangxiong; Zhang Decun; Zhang Yi

    2014-01-01

    Conclusion: With the rapid development of nuclear power in the next few years, uranium demand will increase accordingly. Overseas uranium development will be the major channel to meet the future requirement of NPP demand in China.

  9. Collect method of uranium hexafluoride

    International Nuclear Information System (INIS)

    Moura, S.C.; Bustillos, O.W.V.

    1991-01-01

    A collect method of uranium hexafluoride was designed, constructed and assembled in Analytical Laboratory from Instituto de Energia Atomica, Sao Paulo, Brazil. This method of collect is main for quality control of uranium hexafluoride. (author)

  10. METHOD OF RECOVERING URANIUM COMPOUNDS

    Science.gov (United States)

    Poirier, R.H.

    1957-10-29

    S>The recovery of uranium compounds which have been adsorbed on anion exchange resins is discussed. The uranium and thorium-containing residues from monazite processed by alkali hydroxide are separated from solution, and leached with an alkali metal carbonate solution, whereby the uranium and thorium hydrorides are dissolved. The carbonate solution is then passed over an anion exchange resin causing the uranium to be adsorbed while the thorium remains in solution. The uranium may be recovered by contacting the uranium-holding resin with an aqueous ammonium carbonate solution whereby the uranium values are eluted from the resin and then heating the eluate whereby carbon dioxide and ammonia are given off, the pH value of the solution is lowered, and the uranium is precipitated.

  11. The case against uranium mining

    International Nuclear Information System (INIS)

    Robotham, F.P.

    1980-01-01

    Australia is a potential uranium supplier. The case against uranium mining is presented. Biological effects of radiation, risks involved in reactor operation and the problems of waste disposal are discussed

  12. Uranium development in Nigeria

    International Nuclear Information System (INIS)

    Karniliyus, J.; Egieya, J.

    2014-01-01

    Nigeria uranium exploration started in 1973. Uranium was found in seven states of the country; Cross River, Adamawa, Taraba, Plateau, Bauchi, Kogi and Kano. Three government agencies were involved. At the end of the various exploration campaigns in 2001, the uranium reserve was estimated at about 200 t U. The Grade ranges from 0.63% - 0-9% at a vertical depth between 130 – 200 m. Currently, the Nigeria Atomic Energy Commission activated in 2006 is charged with the responsibility among others to prospect for and mine radioactive minerals. The main aim of this poster presentation is to review the development of uranium in Nigeria with a view to encourage local and international investors to develop and exploit these deposits. Nigeria is located on latitude 100 N and longitude 80 E surrounded in the north by Niger and Chad, in the east by Cameroun and in the west by the Benin Republic. Available data indicated the viability of mineral investment in the Nigerian uranium resources. With the current economic reforms and investment incentives in Nigeria, interested investors are highly welcome to take advantage of developing these mineral resources. (author)

  13. Uranium tailings sampling manual

    International Nuclear Information System (INIS)

    Feenstra, S.; Reades, D.W.; Cherry, J.A.; Chambers, D.B.; Case, G.G.; Ibbotson, B.G.

    1985-01-01

    The purpose of this manual is to describe the requisite sampling procedures for the application of uniform high-quality standards to detailed geotechnical, hydrogeological, geochemical and air quality measurements at Canadian uranium tailings disposal sites. The selection and implementation of applicable sampling procedures for such measurements at uranium tailings disposal sites are complicated by two primary factors. Firstly, the physical and chemical nature of uranium mine tailings and effluent is considerably different from natural soil materials and natural waters. Consequently, many conventional methods for the collection and analysis of natural soils and waters are not directly applicable to tailings. Secondly, there is a wide range in the physical and chemical nature of uranium tailings. The composition of the ore, the milling process, the nature of tailings depositon, and effluent treatment vary considerably and are highly site-specific. Therefore, the definition and implementation of sampling programs for uranium tailings disposal sites require considerable evaluation, and often innovation, to ensure that appropriate sampling and analysis methods are used which provide the flexibility to take into account site-specific considerations. The following chapters describe the objective and scope of a sampling program, preliminary data collection, and the procedures for sampling of tailings solids, surface water and seepage, tailings pore-water, and wind-blown dust and radon

  14. Uranium hexafluoride handling

    International Nuclear Information System (INIS)

    1991-01-01

    The United States Department of Energy, Oak Ridge Field Office, and Martin Marietta Energy Systems, Inc., are co-sponsoring this Second International Conference on Uranium Hexafluoride Handling. The conference is offered as a forum for the exchange of information and concepts regarding the technical and regulatory issues and the safety aspects which relate to the handling of uranium hexafluoride. Through the papers presented here, we attempt not only to share technological advances and lessons learned, but also to demonstrate that we are concerned about the health and safety of our workers and the public, and are good stewards of the environment in which we all work and live. These proceedings are a compilation of the work of many experts in that phase of world-wide industry which comprises the nuclear fuel cycle. Their experience spans the entire range over which uranium hexafluoride is involved in the fuel cycle, from the production of UF 6 from the naturally-occurring oxide to its re-conversion to oxide for reactor fuels. The papers furnish insights into the chemical, physical, and nuclear properties of uranium hexafluoride as they influence its transport, storage, and the design and operation of plant-scale facilities for production, processing, and conversion to oxide. The papers demonstrate, in an industry often cited for its excellent safety record, continuing efforts to further improve safety in all areas of handling uranium hexafluoride

  15. Uranium hexafluoride handling. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-31

    The United States Department of Energy, Oak Ridge Field Office, and Martin Marietta Energy Systems, Inc., are co-sponsoring this Second International Conference on Uranium Hexafluoride Handling. The conference is offered as a forum for the exchange of information and concepts regarding the technical and regulatory issues and the safety aspects which relate to the handling of uranium hexafluoride. Through the papers presented here, we attempt not only to share technological advances and lessons learned, but also to demonstrate that we are concerned about the health and safety of our workers and the public, and are good stewards of the environment in which we all work and live. These proceedings are a compilation of the work of many experts in that phase of world-wide industry which comprises the nuclear fuel cycle. Their experience spans the entire range over which uranium hexafluoride is involved in the fuel cycle, from the production of UF{sub 6} from the naturally-occurring oxide to its re-conversion to oxide for reactor fuels. The papers furnish insights into the chemical, physical, and nuclear properties of uranium hexafluoride as they influence its transport, storage, and the design and operation of plant-scale facilities for production, processing, and conversion to oxide. The papers demonstrate, in an industry often cited for its excellent safety record, continuing efforts to further improve safety in all areas of handling uranium hexafluoride. Selected papers were processed separately for inclusion in the Energy Science and Technology Database.

  16. International uranium market

    International Nuclear Information System (INIS)

    Neff, T.L.; Jacoby, H.D.

    1980-12-01

    Discussed in this report are 1) how one might think about uranium demand, resources and supply, 2) how producers and consumers see the market and are likely to behave, including specifics about export and import commitments, and 3) how these actors are brought together in the international market. The general conclusion is that much of current anxiety about future uranium supply results primarily from a brief but difficult period in the mid- to late-1970's; and that current conditions and trends are favorable (at least to consumers) that there is now little basis for concern. Inventories contractual positions and producer commitments--when compared with realistic (or even unrealistic) demand estimates--imply a buyer's market for at least the next decade. The result will be considerable increases in market flexibility and resilience to shock, and real prices that are low relative to those of the past few years. There is a need to reconsider assumptions about desired directions of technological development, for many current programs were planned in an era of pessimism about uranium supply and process. Similar questions must be raided about nonproliferation policies that depend on some level of control of fuel supplies by the industrial nations. With a soft and more diversified uranium market, leverage that may have existed in the past is rapidly being eroded. Finally, as world prices turn soft, there may be significant problems created for U.S. uranium producers, who have relatively high costs in relation to several large-scale foreign suppliers

  17. Domestic uranium exploration activities

    International Nuclear Information System (INIS)

    Chenoweth, W.L.

    1980-01-01

    Uranium exploration in the United States reached its alltime high in 1978 when the chief exploration indicator, surface drilling, totaled 47 million feet. In 1979, however, total drilling declined to 41 million feet, and during the first 8 months of 1980 the trend continued, as surface drilling was 27% less than for the same period in 1979. The total drilling for 1980 now is expected to be below 30 million feet, far less than the 39.4 million feet planned by industry at the beginning of the year. Falling uranium prices, the uncertainties of future uranium demand, rising costs, and the possibility of stiff foreign competition are the prime causes for the current reduction in domestic uranium exploration. Uranium exploration in the United States continues to be concentrated in the vicinity of major producing areas such as the San Juan Basin, Wyoming Basins, Texas Coastal Plain, Paradox Basin, and northeastern Washington, and in areas of recent discoveries including the Henry Mountains, Utah, the McDermitt caldera in Nevada and Oregon, and central Colorado. The distributions, by location, of total surface drilling for 1979 and the first half of 1980 are presented

  18. Radiation damage of metal uranium

    International Nuclear Information System (INIS)

    Mihajlovic, A.

    1965-01-01

    This report is concerned with the role of dispersion second phase in uranium and burnup rate. The role of dispersion phases in radiation stability of metal uranium was studies by three methods: variation of electric conductivity dependent on the neutron flux and temperature of pure uranium for different states of dispersion second phase; influence of dispersion phase on the radiation creep; transmission electron microscopy of fresh and irradiated uranium

  19. Uranium market 1986-2000

    Energy Technology Data Exchange (ETDEWEB)

    1986-01-01

    The report on the uranium market describes the technical and economic factors influencing the nuclear fuel industry in mid-1986. The contents of the report includes a discussion of: the nuclear generating capacity, the demand for uranium (requirements and procurements), supplies of uranium, and the interaction between supply and demand. The report does not study in depth the effects of the Chernobyl accident on the uranium market.

  20. Uranium resources, production and demand

    International Nuclear Information System (INIS)

    1988-01-01

    Nuclear power-generating capacity will continue to expand, albeit at a slower pace than during the past fifteen years. This expansion must be matched by an adequately increasing supply of uranium. This report compares uranium supply and demand data in free market countries with the nuclear industry's natural uranium requirements up to the year 2000. It also reviews the status of uranium exploration, resources and production in 46 countries

  1. The economics of uranium demand

    International Nuclear Information System (INIS)

    Owen, A.D.

    1983-01-01

    The major characteristics of the demand for uranium are identified, and a number of factors which determine the actual level of uranium requirements of the nuclear power industry are discussed. Since the role of inventories is central to the process of short-term price formation, by comparing projections of uranium production and apparent consumption, the relative level of total inventories is calculated and an assessment is made of its likely impact on the uranium market during the 1980s. (author)

  2. The Toxicity of Depleted Uranium

    OpenAIRE

    Briner, Wayne

    2010-01-01

    Depleted uranium (DU) is an emerging environmental pollutant that is introduced into the environment primarily by military activity. While depleted uranium is less radioactive than natural uranium, it still retains all the chemical toxicity associated with the original element. In large doses the kidney is the target organ for the acute chemical toxicity of this metal, producing potentially lethal tubular necrosis. In contrast, chronic low dose exposure to depleted uranium may not produce a c...

  3. Uranium occurrences and exploration experience in India

    International Nuclear Information System (INIS)

    Chaki, A.

    2010-01-01

    As per the Indian Government laws, minerals containing uranium are classified as strategic and uranium exploration and mining is an exclusive subject of the Central Government. Exploration for atomic minerals began in India in the year 1949 and, over a period of sixty years, India has created a large pool of uranium scientists and, at present, more than 500 scientists are employed by the Government of India for exploration of atomic minerals in India. In line with other countries, India's efforts in the 1960s, 1970s and 1980s were focused in the exploration for vein-type mineralization and succeeded in the discovery in three provinces, viz. Singhbhum Shear Zone (SSZ), Jharkhand; Umra, Rajasthan and Lesser Himalayas of Uttarakhand and Himachal Pradesh. Of these, the SSZ has emerged as a major uranium province with 17 low-grade, low- to medium-tonnage deposits. Presently, the only uranium producing mines are situated in this province. Simultaneously, many uranium occurrences and deposits of QPC, vein and metasomatite types, essentially of low grade, low tonnage, were located all over the country. In the early eighties, the Cretaceous Mahadek basin in the northeastern state of Meghalaya was recognized as a potential province for sandstone-type uranium mineralization and, within a span of fifteen years, five low- to medium-grade, low-tonnage deposits were established. The 180-km long belt of Cretaceous fluviatile felspathic sandstones along the southern fringe of Shillong plateau below a moderate cover of tertiary sediments holds potential for more resources. Ground and airborne geophysical techniques are being looked at to provide vital clues on depositional controls for future sub-surface exploration. In the mean time, a major uranium province in the southern part of Proterozoic Cuddapah basin was discovered, where uranium mineralization is hosted in dolomitic limestone. The mineralization is stratabound and occurs intermittently over a strike length of nearly 160 km

  4. Uranium extraction from underground deposits

    International Nuclear Information System (INIS)

    Wolfe, C.R.

    1982-01-01

    Uranium is extracted from underground deposits by passing an aqueous oxidizing solution of carbon dioxide over the ore in the presence of calcium ions. Complex uranium carbonate or bicarbonate ions are formed which enter the solution. The solution is forced to the surface and the uranium removed from it

  5. Uranium resources, demand and production

    International Nuclear Information System (INIS)

    Stipanicic, P.N.

    1985-05-01

    Estimations of the demand and production of principal uranium resource categories are presented. The estimations based on data analysis made by a joint 'NEA/IAEA Working Party on Uranium Resources' and the corresponding results are published by the OECD (Organization for Economic Co-operation and Development) in the 'Uranium Resources, Production and Demand' Known as 'Red Book'. (M.C.K.) [pt

  6. Uranium. Resources, production and demand

    International Nuclear Information System (INIS)

    1997-01-01

    The events characterising the world uranium market in the last several years illustrate the persistent uncertainly faced by uranium producers and consumers worldwide. With world nuclear capacity expanding and uranium production satisfying only about 60 per cent of demand, uranium stockpiles continue to be depleted at a high rate. The uncertainty related to the remaining levels of world uranium stockpiles and to the amount of surplus defence material that will be entering the market makes it difficult to determine when a closer balance between uranium supply and demand will be reached. Information in this report provides insights into changes expected in uranium supply and demand until well into the next century. The 'Red Book', jointly prepared by the OECD Nuclear Energy Agency and the International Atomic Energy Agency, is the foremost reference on uranium. This world report is based on official information from 59 countries and includes compilations of statistics on resources, exploration, production and demand as of 1 January 1997. It provides substantial new information from all of the major uranium producing centres in Africa, Australia, Eastern Europe, North America and the New Independent States, including the first-ever official reports on uranium production in Estonia, Mongolia, the Russian Federation and Uzbekistan. It also contains an international expert analysis of industry statistics and worldwide projections of nuclear energy growth, uranium requirements and uranium supply

  7. Uranium industry in the USSR

    International Nuclear Information System (INIS)

    Nikipelov, B.V.; Chernov, A.G.

    1990-01-01

    A brief historical account of the Soviet production of natural and enriched uranium is given. The geological and geographical location of major uranium deposits are mentioned. The processing of natural ores including in-situ leaching (ISL) is also briefly described. Gas centrifuges play a large part in uranium enrichment. The role of Techsnabexport for the export of nuclear materials is explained

  8. Uranium content of Philippine coals

    International Nuclear Information System (INIS)

    De la Rosa, A.M.; Sombrito, E.Z.; Nuguid, Z.S.; Bulos, A.M.; Bucoy, B.M.; De la Cruz, M.

    1984-01-01

    Uranium content of coal samples from seven areas in the Philippines, i.e. Cebu, Semirara, Bislig, Albay, Samar, Malangas and Polilio Is. was found to contain trace quantities of uranium. The mean value of 0.401 ppm U is lower than reported mean uranium contents for coal from other countries. (ELC)

  9. Sandstone-type uranium deposits

    International Nuclear Information System (INIS)

    Finch, W.I.; Davis, J.F.

    1985-01-01

    World-class sandstone-type uranium deposits are defined as epigenetic concentrations of uranium minerals occurring as uneven impregnations and minor massive replacements primarily in fluvial, lacustrine, and deltaic sandstone formations. The main purpose of this introductory paper is to define, classify, and introduce to the general geologic setting for sandstone-type uranium deposits

  10. EXTRACTION OF URANIUM

    Science.gov (United States)

    Kesler, R.D.; Rabb, D.D.

    1959-07-28

    An improved process is presented for recovering uranium from a carnotite ore. In the improved process U/sub 2/O/sub 5/ is added to the comminuted ore along with the usual amount of NaCl prior to roasting. The amount of U/sub 2/O/ sub 5/ is dependent on the amount of free calcium oxide and the uranium in the ore. Specifically, the desirable amount of U/sub 2/O/sub 5/ is 3.2% for each 1% of CaO, and 5 to 6% for each 1% of uranium. The mixture is roasted at about 1560 deg C for about 30 min and then leached with a 3 to 9% aqueous solution of sodium carbonate.

  11. Uranium extraction technology

    International Nuclear Information System (INIS)

    1993-01-01

    In 1983 the Nuclear Energy Agency of the Organisation for Economic Co-operation and Development (OECD/NEA) and the IAEA jointly published a book on Uranium Extraction Technology. A primary objective of this report was to document the significant technological developments that took place during the 1970s. The purpose of this present publication is to update and expand the original book. It includes background information about the principle of the unit operations used in uranium ore processing and summarizes the current state of the art. The publication also seeks to preserve the technology and the operating 'know-how' developed over the past ten years. This publication is one of a series of Technical Reports on uranium ore processing that have been prepared by the Division of Nuclear Fuel Cycle and Waste Management at the IAEA. A complete list of these reports is included as an addendum. Refs, figs and tabs

  12. Uranium exploration in Ecuador

    International Nuclear Information System (INIS)

    Severne, B.; Penaherrera, P.F.; Fiallos, V.S.

    1981-01-01

    The 600-km segment of the Andean Cordillera in Ecuador includes zones that can be correlated, geologically, with uranium districts elsewhere in the Andes. It is believed that these essentially unexplored zones have the potential for economic uranium mineralization. Exploration activity to date has been limited, although it has involved both geochemical and radiometric techniques to evaluate geological concepts. Minor uranium occurrences (with chemical analyses up to 100 ppm) have been encountered, which provide further incentive to commence large-scale systematic exploration. It is recognized that a very large exploration budget and considerable technical expertise will be required to ensure exploration success. Consequently, participation by groups of proven capability from other countries will be sought for Ecuador's national exploration programme. (author)

  13. Uranium Enrichment, an overview

    International Nuclear Information System (INIS)

    Coates, J.H.

    1994-01-01

    This general presentation on uranium enrichment will be followed by lectures on more specific topics including descriptions of enrichment processes and assessments of the prevailing commercial and industrial situations. I shall therefore avoid as much as possible duplications with these other lectures, and rather dwell on: some theoretical aspects of enrichment in general, underlying the differences between statistical and selective processes, a review and comparison between enrichment processes, remarks of general order regarding applications, the proliferation potential of enrichment. It is noteworthy that enrichment: may occur twice in the LWR fuel cycle: first by enriching natural uranium, second by reenriching uranium recovered from reprocessing, must meet LWR requirements, and in particular higher assays required by high burn up fuel elements, bears on the structure of the entire front part of the fuel cycle, namely in the conversion/reconversion steps only involving UF 6 for the moment. (author). tabs., figs., 4 refs

  14. The Kintyre uranium project

    International Nuclear Information System (INIS)

    Larson, B.

    1997-01-01

    The Kintyre Uranium Project is being developed by Canning Resources Pty Ltd, a subsidiary of Rio Tinto (formerly CRA). The work on the project includes the planning and management of a number of background environmental studies. The company has also commissioned studies by external consultants into process technologies, mining strategies and techniques for extracting the uranium ore from the waste rock. In addition, Canning Resources has made a detailed assessment of the worldwide market potential for Australian uranium in the late 1990s and into the 21st century. The most significant factor affecting the future of this project is the current product price. This price is insufficient to justify the necessary investment to bring this project into production

  15. Uranium market and resources

    International Nuclear Information System (INIS)

    Capus, G.; Arnold, T.

    2005-01-01

    Under the combined effect of various factors, such as interrogations related to facing the climatic changes, the increasing prices of oil versus announced decrease of its resources, the major geopolitical evolution and the remarkable development of Asia, we live nowadays a revival of nuclear power in the very front of stage. In tis context, the following question is posed: could the nuclear fission be a sustainable source of energy when taking into consideration the availability of uranium resources? The article aims at pinpointing the knowledge we have about the world uranium resources, their limits of uncertainty and the relation between knowledge resources and market evolution. To conclude, some susceptible tracks are proposed to improve the using process of uranium resources particularly in softening the impact of high prices

  16. Uranium ore processing

    International Nuclear Information System (INIS)

    Ritcey, G.M.; Haque, K.E.; Lucas, B.H.; Skeaff, J.M.

    1983-01-01

    The authors have developed a complete method of recovering separately uranium, thorium and radium from impure solids such as ores, concentrates, calcines or tailings containing these metals. The technique involves leaching, in at least one stage. The impure solids in finely divided form with an aqueous leachant containing HCl and/or Cl 2 until acceptable amounts of uranium, thorium and radium are dissolved. Uranium is recovered from the solution by solvent extraction and precipitation. Thorium may also be recovered in the same manner. Radium may be recovered by at least one ion exchange, absorption and precipitation. This amount of iron in the solution must be controlled before the acid solution may be recycled for the leaching process. The calcine leached in the first step is prepared in a two stage roast in the presence of both Cl 2 and a metal sulfide. The first stage is at 350-450 0 and the second at 550-700 0

  17. Process for recovering uranium

    Science.gov (United States)

    MacWood, G. E.; Wilder, C. D.; Altman, D.

    1959-03-24

    A process useful in recovering uranium from deposits on stainless steel liner surfaces of calutrons is presented. The deposit is removed from the stainless steel surface by washing with aqueous nitric acid. The solution obtained containing uranium, chromium, nickel, copper, and iron is treated with an excess of ammonium hydroxide to precipitnte the uranium, iron, and chromium and convert the nickel and copper to soluble ammonio complexions. The precipitated material is removed, dried and treated with carbon tetrachloride at an elevated temperature of about 500 to 600 deg C to form a vapor mixture of UCl/ sub 4/, UCl/sub 5/, FeCl/sub 3/, and CrCl/sub 4/. The UCl/sub 4/ is separated from this vapor mixture by selective fractional condensation at a temperature of about 500 to 400 deg C.

  18. Australian uranium resources

    International Nuclear Information System (INIS)

    Battey, G.C.; Miezitis, Y.; McKay, A.D.

    1987-01-01

    Australia's uranium resources amount to 29% of the WOCA countries (world outside centrally-planned-economies areas) low-cost Reasonably Assured Resources and 28% of the WOCA countries low-cost Estimated Additional Resources. As at 1 January 1986, the Bureau of Mineral Resources estimated Australia's uranium resources as: (1) Cost range to US$80/kg U -Reasonably Assured Resources, 465 000 t U; Estimated Additional Resources, 256 000 t U; (2) Cost range US$80-130/kg U -Reasonably Assured Resources, 56 000 t U; Estimated Additional Resources, 127 000 t U. Most resources are contained in Proterozoic unconformity-related deposits in the Alligator Rivers uranium field in the Northern Territory (Jabiluka, Ranger, Koongarra, Nabarlek deposits) and the Proterozoic stratabound deposit at Olympic Dam on the Stuart Shelf in South Australia

  19. Uranium deposits of Zaire

    International Nuclear Information System (INIS)

    Kitmut, D.; Malu wa Kalenga

    1979-01-01

    Since April 1960, following the closing of the Shinkolobwe mine, the Republic of Zaire has ceased to be a producer of uranium. Nevertheless, Gecamines (Generale des carrieres et mines du Zaire), a wholly state-owned company, is continuing its research on uranium occurrences which have been discovered in its concession in the course of aerial radiometric prospecting. The most recent campaign was the one carried out in 1969 and 1972 by Hunting Company. On-the-ground verification of these shows has not yet resulted in the discovery of a workable deposit. There are other sectors cutting across Zaire which might well contain uranium deposits: this is true of the sedimentary phosphates of the region of Lower Zaire as well as of the frontier region between Zaire and the Central African Empire. However, no detailed exploration work has yet been carried out. (author)

  20. Uranium extraction from seawater

    International Nuclear Information System (INIS)

    Bals, H.G.

    1976-03-01

    After an introduction to the physics and chemistry of the sea and an estimation of the chances for the absorption of uranium from rivers, the material-sepecific characteristics of the adsorber technology are decribed in detail. Then, the methods used for gaining uranium form seawater are described with special regard to the tidal and the so-called serial (sequency) method. Whether all methods described can be realised is an economic problem since very high quantitics of water are necessary because of the low contents of uranium. A positive energy balance (gained energy/lost energy) is not definitely ensured yet for the production methods used. The development measures to be taken to obtain a positive energy balance are briefly described, and the research programme of the UEBG is mentioned. (UA) [de

  1. Uranium dioxide calcining apparatus

    International Nuclear Information System (INIS)

    Cole, E.A.; Peterson, R.S.

    1978-01-01

    This invention relates to an improved continuous calcining apparatus for consistently and controllably producing from calcinable reactive solid compounds of uranium, such as ammonium diuranate, uranium dioxide (UO 2 ) having an oxygen to uranium ratio of less than 2.2. The apparatus comprises means at the outlet end of a calciner kiln for receiving hot UO 2 , means for cooling the UO 2 to a temperature of below 100 deg C and conveying the cooled UO 2 to storage or to subsequent UO 2 processing apparatus where it finally comes into contact with air, the means for receiving cooling and conveying being sealed to the outlet end of the calciner and being maintained full of UO 2 and so operable as to exclude atmospheric oxygen from coming into contact with any UO 2 which is at elevated temperatures where it would readily oxidize, without the use of extra hydrogen gas in said means. (author)

  2. The uranium International trade

    International Nuclear Information System (INIS)

    Gonzalez U, L.A.

    1993-01-01

    The aim of this thesis is the understanding of how the present dynamic of uranium International trade is developed, the variables which fall into, the factors that are affecting and conditioning it, in order to clarify which are going to be the outlook in the future of this important resource in front of the present ecological situation and the energetic panorama of XXI Century. For this purpose, as starting point, the uranium is considered as a strategic material which importance take root in its energetic potential as alternate energy source, and for this reason in Chapter I, the general problem of raw materials, its classification and present situation in the global market is presented. In Chapter II, by means of a historical review, is explain what uranium is, how it was discovered, and how since the end of the past Century and during the last three decades of present, uranium pass of practically unknown element, to the position of a strategic raw material, which by degrees, generate an International market, owing to its utilization as a basic resource in the generation of energy. Chapter III, introduce us in the roll played by uranium, since its warlike applications until its utilization in nuclear reactors for the generation of electricity. Also is explain the reason for this change in the perception at global level. Finally, in Chapter IV we enter upon specifically in the present conditions of the International market of this mineral throughout the trends of supply and demand, the main producers, users, price dynamics, and the correlation among these economical variables and other factors of political, social and ecological nature. All of these with the purpose to found out, if there exist, a meaning of the puzzle that seems to be the uranium International trade

  3. US uranium reserves

    International Nuclear Information System (INIS)

    Hansen, M.V.

    1981-01-01

    The current low level of demand, compounded by rapidly rising costs and low prices, has caused a significant reduction in drilling for uranium in the United States, and the trend is likely to continue for a few more years. The effect on uranium reserves will be fewer additions to reserves because less exploration is being done. Further reductions will occur, especially in low-cost reserves, because of increasing costs, continuing depletion through production, and erosion through the high grading of deposits to fulfill previous contractual commitments. During the past several years, it has been necessary to increase the upper reserve cost level twice to compensate for rising costs. Rising costs are reducing the $15 reserves, the cost category corresponding most closely to the present market price, to an insignificant level. An encouraging factor related to US uranium reserves is that the US position internationally, as far as quantity is concerned, is not bad for the longer term. Also, there is a general opinion that US consumers would rather contract for domestic uranium than for foreign because of greater assurance of supply. Still another factor, nearly impossible to assess, is what effect rising costs in other countries will have on their uranium reserves. The annual conferences between the Grand Junction Area Office staff and major uranium companies provide a broad overview of the industry's perception of the future. It is not optimistic for the short term. Many companies are reducing their exploration and mining programs; some are switching to other more marketable mineral commodities, and a few are investing more heavily in foreign ventures. However, there is general optimism for the long term, and many predict a growth in demand in the mid-1980s. If the industry can survive the few lean years ahead, rising prices may restore its viability to former levels

  4. Brazilian uranium reserves

    International Nuclear Information System (INIS)

    Marques, J.P.M.

    1981-01-01

    Due to a growing demand of electric power to support Brasil's development, the use of nuclear energy will be indispensable. The nuclear fuel cycle for the production of energy, starts with the uranium exploration. The work performed in this field led to the discovery of several deposits in the country, which to-date totalize a reserve of 236,300t of U 308 , ranking Brazil in the 6th place among the nations of the western world holding uranium reserves. (Author) [pt

  5. METHOD OF ELECTROPOLISHING URANIUM

    Science.gov (United States)

    Walker, D.E.; Noland, R.A.

    1959-07-14

    A method of electropolishing the surface of uranium articles is presented. The process of this invention is carried out by immersing the uranium anticle into an electrolyte which contains from 35 to 65% by volume sulfuric acid, 1 to 20% by volume glycerine and 25 to 50% by volume of water. The article is made the anode in the cell and polished by electrolyzing at a voltage of from 10 to 15 volts. Discontinuing the electrolysis by intermittently withdrawing the anode from the electrolyte and removing any polarized film formed therein results in an especially bright surface.

  6. Uranium ore deposits

    International Nuclear Information System (INIS)

    Angelelli, Victorio.

    1984-01-01

    The main uranium deposits and occurrences in the Argentine Republic are described, considering, in principle, their geologic setting, the kind of 'model' of the mineralization and its possible origin, and describing the ore species present in each case. The main uraniferous accumulations of the country include the models of 'sandstong type', veintype and impregnation type. There are also other kinds of accumulations, as in calcrete, etc. The main uranium production has been registered in the provinces of Mendoza, Salta, La Rioja, Chubut, Cordoba and San Luis. In each case, the minerals present are mentioned, having been recognized 37 different species all over the country (M.E.L.) [es

  7. PRODUCTION OF URANIUM TUBING

    Science.gov (United States)

    Creutz, E.C.

    1958-04-15

    The manufacture of thin-walled uranium tubing by the hot-piercing techique is described. Uranium billets are preheated to a temperature above 780 d C. The heated billet is fed to a station where it is engaged on its external surface by three convex-surfaced rotating rollers which are set at an angle to the axis of the billet to produce a surface friction force in one direction to force the billet over a piercing mandrel. While being formed around the mandrel and before losing the desired shape, the tube thus formed is cooled by a water spray.

  8. Joining uranium to steel

    International Nuclear Information System (INIS)

    Perkins, M.A.

    1976-05-01

    A method has been devised which will allow the joining of uranium to steel by fusion welding through the use of an intermediate material. Uranium-0.5 titanium was joined to AISI 304L stainless steel by using a vanadium insert. Also, a method is now available for selecting possible filler metals when two entirely dissimilar metals need to be joined. This method allows a quantitative ranking to be made of the possible filler metals and thus the most likely candidate can be selected

  9. Uranium mill tailings management

    International Nuclear Information System (INIS)

    1982-01-01

    Facilities for the disposal of uranium mill tailings will invariably be subjected to geomorphological and climatological influences in the long-term. Proceedings of a workshop discuss how the principles of geomorphology can be applied to the siting, design, construction, decommissioning and rehabilitation of disposal facilities in order to provide for long-term containment and stability of tailings. The characteristics of tailings and their behaviour after disposal influence the potential impacts which might occur in the long-term. Proceedings of another workshop examine the technologies for uranium ore processing and tailings conditioning with a view to identifying improvements that could be made in such characteristics

  10. Uranium exploration techniques

    International Nuclear Information System (INIS)

    Nichols, C.E.

    1984-01-01

    The subject is discussed under the headings: introduction (genetic description of some uranium deposits; typical concentrations of uranium in the natural environment); sedimentary host rocks (sandstones; tabular deposits; roll-front deposits; black shales); metamorphic host rocks (exploration techniques); geologic techniques (alteration features in sandstones; favourable features in metamorphic rocks); geophysical techniques (radiometric surveys; surface vehicle methods; airborne methods; input surveys); geochemical techniques (hydrogeochemistry; petrogeochemistry; stream sediment geochemistry; pedogeochemistry; emanometry; biogeochemistry); geochemical model for roll-front deposits; geologic model for vein-like deposits. (U.K.)

  11. Uranium Conversion & Enrichment

    Energy Technology Data Exchange (ETDEWEB)

    Karpius, Peter Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-06

    The isotopes of uranium that are found in nature, and hence in ‘fresh’ Yellowcake’, are not in relative proportions that are suitable for power or weapons applications. The goal of conversion then is to transform the U3O8 yellowcake into UF6. Conversion and enrichment of uranium is usually required to obtain material with enough 235U to be usable as fuel in a reactor or weapon. The cost, size, and complexity of practical conversion and enrichment facilities aid in nonproliferation by design.

  12. Uranium extraction at Rossing

    International Nuclear Information System (INIS)

    Kesler, S.B.; Fahrbach, D.O.E.

    1982-01-01

    Rossing Uranium Ltd. operates a large open pit uranium mine and extraction plant at a remote site in the Namib desert. Production started at the plant in 1978. A ferric leach process was introduced later, and the new leach plant began commissioning in October 1981. The process has proved to be reliable and easily controlled. Ferric iron is supplied through recovery from the acid plant calcine, and levels can be maintained above the design levels. Leach extractions were increased more than expected when this process was adopted, and the throughput has been considerably reduced, allowing cost savings in mining and milling

  13. Uranium conversion wastes

    International Nuclear Information System (INIS)

    Vicente, R.; Dellamano, J.C.

    1989-12-01

    A set of mathematical equations was developed and used to estimate the radiological significance of each radionuclide potentially present in the uranium refining industry effluents. The equations described the evolution in time of the radionuclides activities in the uranium fuel cycle, from mining and milling, through the yellowcake, till the conversion effluents. Some radionuclides that are not usually monitored in conversion effluents (e.g. Pa-231 and Ac-227) were found to be potentially relevant from the radiological point of view in conversion facilities, and are certainly relevant in mining and milling industry, at least in a few waste streams. (author) [pt

  14. Production of sized particles of uranium oxides and uranium oxyfluorides

    International Nuclear Information System (INIS)

    Knudsen, I.E.; Randall, C.C.

    1976-01-01

    A process is claimed for converting uranium hexafluoride (UF 6 ) to uranium dioxide (UO 2 ) of a relatively large particle size in a fluidized bed reactor by mixing uranium hexafluoride with a mixture of steam and hydrogen and by preliminary reacting in an ejector gaseous uranium hexafluoride with steam and hydrogen to form a mixture of uranium and oxide and uranium oxyfluoride seed particles of varying sizes, separating the larger particles from the smaller particles in a cyclone separator, recycling the smaller seed particles through the ejector to increase their size, and introducing the larger seed particles from the cyclone separator into a fluidized bed reactor where the seed particles serve as nuclei on which coarser particles of uranium dioxide are formed. 9 claims, 2 drawing figures

  15. Uranium 2000 : International symposium on the process metallurgy of uranium

    International Nuclear Information System (INIS)

    Ozberk, E.; Oliver, A.J.

    2000-01-01

    The International Symposium on the Process Metallurgy of Uranium has been organized as the thirtieth annual meeting of the Hydrometallurgy Section of the Metallurgical Society of the Canadian Institute of Mining, Metallurgy and Petroleum (CIM). This meeting is jointly organized with the Canadian Mineral Processors Division of CIM. The proceedings are a collection of papers from fifteen countries covering the latest research, development, industrial practices and regulatory issues in uranium processing, providing a concise description of the state of this industry. Topics include: uranium industry overview; current milling operations; in-situ uranium mines and processing plants; uranium recovery and further processing; uranium leaching; uranium operations effluent water treatment; tailings disposal, water treatment and decommissioning; mine decommissioning; and international regulations and decommissioning. (author)

  16. Uranium material removing and recovering device

    International Nuclear Information System (INIS)

    Takita, Shin-ichi.

    1997-01-01

    A uranium material removing and recovering device for use in removing surplus uranium heavy metal (UO 2 ) generated in a uranium handling facility comprises a uranium material removing device and a uranium material recovering device. The uranium material removing device comprises an adsorbing portion filled with a uranium adsorbent, a control portion for controlling the uranium adsorbent of the uranium adsorbing portion by a controlling agent, a uranium adsorbing device connected thereto and a jetting device for jetting the adsorbing liquid to equipments deposited with uranium. The recovering device comprises a recovering apparatus for recovering uranium materials deposited with the adsorbent liquid removed by the jetting device and a recovering tank for storing the recovered uranium materials. The device of the present invention can remove surplus uranium simply and safely, mitigate body's load upon removing and recovering operations, facilitate the processing for the exchange of the adsorbent and reduces the radioactive wastes. (T.M.)

  17. Uranium enriched granites in Sweden

    International Nuclear Information System (INIS)

    Wilson, M.R.; Aakerblom, G.

    1980-01-01

    Granites with uranium contents higher than normal occur in a variety of geological settings in the Swedish Precambrian, and represent a variety of granite types and ages. They may have been generated by (1) the anatexis of continental crust (2) processes occurring at a much greater depth. They commonly show enrichement in F, Sn, W and/or Mo. Only in one case is an important uranium mineralization thought to be directly related to a uranium-enriched granite, while the majority of epigenetic uranium mineralizations with economic potential are related to hydrothermal processes in areas where the bedrock is regionally uranium-enhanced. (Authors)

  18. The uranium market 1980 - 1990

    International Nuclear Information System (INIS)

    Darmayan, Philippe

    1980-01-01

    The Supply and Demand Committee of the Uranium Institute was established to monitor continuously information and developments bearing on the uranium market and to publish from time to time reports giving its views on the supply and demand outlook. The last Uranium institute supply and demand report was published in July 1979 and a summary was given by Mr. Erkes at the last Uranium Institute symposium. Its main conclusions were that from 1979 to 1990 the flexibilities of the market were such as to offer adequate scope to producers and consumers of uranium to ensure a balance between supply and demand. Is that conclusion still valid one and a half years later [fr

  19. Fault rocks and uranium mineralization

    International Nuclear Information System (INIS)

    Tong Hangshou.

    1991-01-01

    The types of fault rocks, microstructural characteristics of fault tectonite and their relationship with uranium mineralization in the uranium-productive granite area are discussed. According to the synthetic analysis on nature of stress, extent of crack and microstructural characteristics of fault rocks, they can be classified into five groups and sixteen subgroups. The author especially emphasizes the control of cataclasite group and fault breccia group over uranium mineralization in the uranium-productive granite area. It is considered that more effective study should be made on the macrostructure and microstructure of fault rocks. It is of an important practical significance in uranium exploration

  20. Recovery of uranium from seawater

    International Nuclear Information System (INIS)

    Hirotsu, Takahiro; Takagi, Norio; Katoh, Shunsaku

    1995-01-01

    Present status of the development of chelating adsorbents for the recovery of uranium from seawater is outlined with emphasis on the research by the author. Uranium is estimated to exist as stable tri (carbonate) uranylate (6) ion in seawater in a very low concentration. The adsorbent for uranium from seawater in a very low concentration. The adsorbent for uranium from seawater should have high selectivity and affinity for uranium around pH 8. The required characteristics for uranium adsorbent are examined. Various chelating adsorbents have been proposed for the uranium adsorbent and their structures are discussed. Amidoxime type adsorbents have the highest adsorbing power for uranium among the adsorbents hitherto developed and fibrous amidoxime adsorbents are most promising for the practical application. Synthesis, structure and suitable shape of the amidoxime adsorbents are discussed. Uranium adsorption behavior and the amount of saturated adsorption are examined theoretically based on the complexation of an amidoxime monomer and the formula for the adsorption equiliburium is derived. The adsorption and recovery process for uranium from seawater is composed of adsorption, desorption, separation and concentration and finally, uranium is recovered as the yellow cake. A floating body mooring system is proposed by Nobukawa. (T.H.)

  1. Sandstone-type uranium deposits

    International Nuclear Information System (INIS)

    Austin, S.R.; D'Andrea, R.F. Jr.

    1978-01-01

    Three overall factors are necessary for formation of uranium deposits in sandstone: a source of uranium, host rocks capable of transmitting uranium-bearing solutions, and a precipitant. Possible sources of uranium in sandstone-type deposits include groundwaters emanating from granitic highlands, arkosic sediments, tuffaceous material within or overlying the host rocks, connate fluids, and overlying black shales. The first three sources are considered the most likely. Host rocks are generally immature sandstones deposited in alluvial-fan, intermontane-basin or marginal-marine environments, but uranium deposits do occur in well-winnowed barrier-bar or eolian sands. Host rocks for uranium deposits generally show coefficients of permeability on the order of 1 to 100 gal/day/ft 2 . Precipitants are normally agents capable of reducing uranium from the uranyl to the uranous state. The association of uranium with organic matter is unequivocal; H 2 S, a powerful reductant, may have been present at the time of formation of some deposits but may go unnoticed today. Vanadium can serve to preserve the tabular characteristics of some deposits in the near-surface environment, but is considered an unlikely primary precipitant for uranium. Uranium deposits in sandstone are divided into two overall types: peneconcordant deposits, which occur in locally reducing environments in otherwise oxidized sandstones; and roll-type deposits, which occur at the margin of an area where an oxidized groundwater has permeated an otherwise reduced sandstone. Uranium deposits are further broken down into four subclasses; these are described

  2. Vaal Reefs South uranium plant

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    The Vaal Reefs mining complex, part of the Anglo American Corporation, is the largest gold and uranium producing complex in the world, being South Africa's principal producer, accounting for about a quarter of the country's uranium production. Vaal Reefs South uranium plant in the Orkney district was recently officially opened by Dr AJA Roux, the retiring president of the Atomic Energy Board and chairman of the Uranium Enrichment Corporation and will increase the country's uranium production. In the field of technology, and particularly processing technology, South Africa has shown the world unprecedented technology achievement in the field of uranium extraction from low grade ores and the development of the unique uranium enrichment process. New technical innovations that have been incorporated in this new plant are discussed

  3. Uranium recovery from AVLIS slag

    International Nuclear Information System (INIS)

    D'Agostino, A.E.; Mycroft, J.R.; Oliver, A.J.; Schneider, P.G.; Richardson, K.L.

    2000-01-01

    Uranium metal for the Atomic Vapor Laser Isotope Separation (AVLIS) project was to have been produced by the magnesiothermic reduction of uranium tetrafluoride. The other product from this reaction is a magnesium fluoride slag, which contains fine and entrained natural uranium as metal and oxide. Recovery of the uranium through conventional mill leaching would not give a magnesium residue free of uranium but to achieve more complete uranium recovery requires the destruction of the magnesium fluoride matrix and liberation of the entrapped uranium. Alternate methods of carrying out such treatments and the potential for recovery of other valuable byproducts were examined. Based on the process flowsheets, a number of economic assessments were performed, conclusions were drawn and the preferred processing alternatives were identified. (author)

  4. Geophysics in uranium exploration

    International Nuclear Information System (INIS)

    Darnley, A.G.

    1975-01-01

    There are no revolutionary new methods of uranium exploration on the horizon. Continuing improvements in existing methods and types of instrumentation are to be expected, but the main scope of improvement will hinge upon using the best of the available methods more meticulously and systematically, and paying more attention to the analysis of data. (author)

  5. The neurotoxicology of uranium

    International Nuclear Information System (INIS)

    Dinocourt, Céline; Legrand, Marie; Dublineau, Isabelle; Lestaevel, Philippe

    2015-01-01

    The brain is a target of environmental toxic pollutants that impair cerebral functions. Uranium is present in the environment as a result of natural deposits and release by human applications. The first part of this review describes the passage of uranium into the brain, and its effects on neurological functions and cognitive abilities. Very few human studies have looked at its cognitive effects. Experimental studies show that after exposure, uranium can reach the brain and lead to neurobehavioral impairments, including increased locomotor activity, perturbation of the sleep-wake cycle, decreased memory, and increased anxiety. The mechanisms underlying these neurobehavioral disturbances are not clearly understood. It is evident that there must be more than one toxic mechanism and that it might include different targets in the brain. In the second part, we therefore review the principal mechanisms that have been investigated in experimental models: imbalance of the anti/pro-oxidant system and neurochemical and neurophysiological pathways. Uranium effects are clearly specific according to brain area, dose, and time. Nonetheless, this review demonstrates the paucity of data about its effects on developmental processes and the need for more attention to the consequences of exposure during development.

  6. Separation of uranium isotopes

    International Nuclear Information System (INIS)

    Porter, J.T.

    1980-01-01

    Methods and apparatus are disclosed for separation of uranium isotopes by selective isotopic excitation of photochemically reactive uranyl salt source material at cryogenic temperatures, followed by chemical separation of selectively photochemically reduced U+4 thereby produced from remaining uranyl source material

  7. Ranger uranium project

    International Nuclear Information System (INIS)

    1979-01-01

    This agreement between the Commonwealth of Australia, Peko-Wallsend Operations Ltd., Electrolytic Zinc Company of Australasia Limited, and the Australian Atomic Energy Commission sets out articles under which the Ranger uranium project in the Northern Territory of Australia is to be operated

  8. Uranium tailings reference materials

    International Nuclear Information System (INIS)

    Smith, C.W.; Steger, H.F.; Bowman, W.S.

    1984-01-01

    Samples of uranium tailings from Bancroft and Elliot Lake, Ontario, and from Beaverlodge and Rabbit Lake, Saskatchewan, have been prepared as compositional reference materials at the request of the National Uranium Tailings Research Program. The four samples, UTS-1 to UTS-4, were ground to minus 104 μm, each mixed in one lot and bottled in 200-g units for UTS-1 to UTS-3 and in 100-g units for UTS-4. The materials were tested for homogeneity with respect to uranium by neutron activation analysis and to iron by an acid-decomposition atomic absorption procedure. In a free choice analytical program, 18 laboratories contributed results for one or more of total iron, titanium, aluminum, calcium, barium, uranium, thorium, total sulphur, and sulphate for all four samples, and for nickel and arsenic in UTS-4 only. Based on a statistical analysis of the data, recommended values were assigned to all elements/constituents, except for sulphate in UTS-3 and nickel in UTS-4. The radioactivity of thorium-230, radium-226, lead-210, and polonium-210 in UTS-1 to UTS-4 and of thorium-232, radium-228, and thorium-228 in UTS-1 and UTS-2 was determined in a radioanalytical program composed of eight laboratories. Recommended values for the radioactivities and associated parameters were calculated by a statistical treatment of the results

  9. Uranium and nuclear issues

    International Nuclear Information System (INIS)

    1983-01-01

    This seminar focussed on the major issues affecting the future of the entire nuclear fuel cycle. In particular it covered issues bearing on the formation of public policy in relation to the use of uranium as an energy source: economic risk, industrial risks, health effects, site selection, environmental issues, and public acceptance

  10. Canada's uranium policies

    International Nuclear Information System (INIS)

    Smith, K.L.; Williams, R.M.

    1991-01-01

    The purpose of this paper is to provide an update on the Canadian Government policies which affect the uranium industry and, where appropriate, to provide some background on the development of these policies. This review is timely because of two recent announcements by the Minister of Energy, Mines and Resources - one concerning the Canadian Government's renewed commitment to maintain the nuclear power option for Canada, and the other concerning some adjustments to Canada's uranium export policy. The future of Canada's nuclear industry was subject to a thorough review by the Canadian Government during 1989. This review occurred at a time when environmental issues were attracting increasing attention around the world, and the environmental advantages of nuclear power were becoming increasingly recognised. The strong support for the nuclear industry in Canada is consistent with the government's long-standing efforts to maintain Canada's position as a reliable and competitive supplier of uranium. This paper is particularly devoted to an outline of the results of the uranium export policy review. (author)

  11. Uranium (IV) carboxylates - I

    Energy Technology Data Exchange (ETDEWEB)

    Satpathy, K C; Patnaik, A K [Sambalpur Univ. (India). Dept. of Chemistry

    1975-11-01

    A few uranium(IV) carboxylates with monochloro and trichloro acetic acid, glycine, malic, citric, adipic, o-toluic, anthranilic and salicylic acids have been prepared by photolytic methods. The I.R. spectra of these compounds are recorded and basing on the spectral data, structure of the compounds have been suggested.

  12. Uranium market remains steady

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    Little change in the world uranium market is reported in the new edition of the NEA/IAEA Red Book published in March. However, the agencies still expect new production capacity to be required by the mid-1990s. Topics covered include: resources, exploration, production and demand. (author)

  13. Uranium distribution and availability

    International Nuclear Information System (INIS)

    Bowie, S.H.U.

    1977-01-01

    Uranium deposits are not uniformly distributed in the earth's crust but occur in well-defined provinces, mainly in Precambrian terrain and in association with acid igneous rocks. Deposits can conveniently be classified into four main groups; uranium in sandstones; uranium in conglomerates; vein-and similar-type deposits; and other uranium deposits. Most of the presently known reserves occur in sandstones; vein-type deposits are now second in importance; conglomerates are third and other deposits, excluding shales, fourth. The shales of southern Sweden constitute a special case; although recoverable reserves are large (300 000 t U), annual production from them is not likely to exceed 1000 to 2000 t U. The estimation of reserves has been complicated by rapid price rises since 1973 and by uncertainty as to what cost or price levels should be adopted in distinguishing between reserves and resources. Also there has been a tendency for requirements to be revised downwards, and this, together with the apparent acceptance of cost levels of around $30/lb U 3 O 8 , has relieved the medium-term prospects so far as supply is concerned. In the longer term, however, there is clearly a need for increased prospecting effort on a world scale and for the introduction of new search methods, particularly those aimed at the detection of hidden orebodies. this requirement will be greatly enhanced if there is any retardation in the introduction of fast reactors. (author)

  14. Uranium reserves fall: AAEC

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    Figures released by the AAEC show that Australia's reasonably assured resources of uranium recoverable at US$80 a kg fell by 5,000 tonnes during 1980-81. Reserves at 30 June 1981 totalled 294,000 tonnes. This represented 17 per cent of the Western World's low cost reasonably assured resources

  15. Uranium resources in New Mexico

    International Nuclear Information System (INIS)

    McLemore, V.T.; Chenoweth, W.L.

    1989-01-01

    For nearly three decades (1951-1980), the Grants uranium district in northwestern New Mexico produced more uranium than any other district in the world. The most important host rocks containing economic uranium deposits in New Mexico are sandstones within the Jurassic Morrison Formation. Approximately 334,506,000 lb of U 3 O 8 were produced from this unit from 1948 through 1987, accounting for 38% of the total uranium production from the US. All of the economic reserves and most of the resources in New Mexico occur in the Morrison Formation. Uranium deposits also occur in sandstones of Paleozoic, Triassic, Cretaceous, Tertiary, and Quaternary formations; however, only 468,680 lb of U 3 O 8 or 0.14% of the total production from New Mexico have been produced from these deposits. Some of these deposits may have a high resource potential. In contrast, almost 6.7 million lb of U 3 O 8 have been produced from uranium deposits in the Todilto Limestone of the Wanakah Formation (Jurassic), but potential for finding additional economic uranium deposits in the near future is low. Other uranium deposits in New Mexico include those in other sedimentary rocks, vein-type uranium deposits, and disseminated magmatic, pegmatitic, and contact metasomatic uranium deposits in igneous and metamorphic rocks. Production from these deposits have been insignificant (less than 0.08% of the total production from New Mexico), but there could be potential for medium to high-grade, medium-sized uranium deposits in some areas. Total uranium production from New Mexico from 1948 to 1987 amounts to approximately 341,808,000 lb of U 3 O 8 . New Mexico has significant uranium reserves and resources. Future development of these deposits will depend upon an increase in price for uranium and lowering of production costs, perhaps by in-situ leaching techniques

  16. Uranium deposits in granitic rocks

    International Nuclear Information System (INIS)

    Nishimori, R.K.; Ragland, P.C.; Rogers, J.J.W.; Greenberg, J.K.

    1977-01-01

    This report is a review of published data bearing on the geology and origin of uranium deposits in granitic, pegmatitic and migmatitic rocks with the aim of assisting in the development of predictive criteria for the search for similar deposits in the U.S. Efforts were concentrated on the so-called ''porphyry'' uranium deposits. Two types of uranium deposits are primarily considered: deposits in pegmatites and alaskites in gneiss terrains, and disseminations of uranium in high-level granites. In Chapter 1 of this report, the general data on the distribution of uranium in igneous and metamorphic rocks are reviewed. Chapter 2 contains some comments on the classification of uranium deposits associated with igneous rocks and a summary of the main features of the geology of uranium deposits in granites. General concepts of the behavior of uranium in granites during crustal evolution are reviewed in Chapter 3. Also included is a discussion of the relationship of uranium mineralization in granites to the general evolution of mobile belts, plus the influence of magmatic and post-magmatic processes on the distribution of uranium in igneous rocks and related ore deposits. Chapter 4 relates the results of experimental studies on the crystallization of granites to some of the geologic features of uranium deposits in pegmatites and alaskites in high-grade metamorphic terrains. Potential or favorable areas for igneous uranium deposits in the U.S.A. are delineated in Chapter 5. Data on the geology of specific uranium deposits in granitic rocks are contained in Appendix 1. A compilation of igneous rock formations containing greater than 10 ppM uranium is included in Appendix 2. Appendix 3 is a report on the results of a visit to the Roessing area. Appendix 4 is a report on a field excursion to eastern Canada

  17. Disposable Amperometric Immunosensor for the Determination of Human P53 Protein in Cell Lysates Using Magnetic Micro-Carriers

    Directory of Open Access Journals (Sweden)

    María Pedrero

    2016-11-01

    Full Text Available An amperometric magnetoimmunosensor for the determination of human p53 protein is described in this work using a sandwich configuration involving the covalent immobilization of a specific capture antibody onto activated carboxylic-modified magnetic beads (HOOC-MBs and incubation of the modified MBs with a mixture of the target protein and horseradish peroxidase-labeled antibody (HRP-anti-p53. The resulting modified MBs are captured by a magnet placed under the surface of a disposable carbon screen-printed electrode (SPCE and the amperometric responses are measured at −0.20 V (vs. an Ag pseudo-reference electrode, upon addition of hydroquinone (HQ as a redox mediator and H2O2 as the enzyme substrate. The magnetoimmunosensing platform was successfully applied for the detection of p53 protein in different cell lysates without any matrix effect after a simple sample dilution. The results correlated accurately with those provided by a commercial ELISA kit, thus confirming the immunosensor as an attractive alternative for rapid and simple determination of this protein using portable and affordable instrumentation.

  18. Piezoelectric immunosensors for the detection of individual antibiotics and the total content of penicillin antibiotics in foodstuffs.

    Science.gov (United States)

    Karaseva, N A; Ermolaeva, T N

    2014-03-01

    Piezoelectric immunosensors on the basis of homologous and group-specificantibodies have been developed for detecting penicillin G, ampicillin, and the total content of penicillin antibiotics. The receptor coating of the sensor was obtained by the immobilization of penicillin G or ampicillin hapten-protein conjugates on the polypyrrole film obtained by electropolymerization and activated by glutaraldehyde. The affinity constants and the cross reactivity coefficients have been calculated. This made it possible to estimate the affinity and specificity of the polyclonal and monoclonal antibodies used. The calibration curves are linear in the range of concentrations 2.5-250.0 ng ml(-1) (penicillin G), 2.5-500.0 ng ml(-1) (ampicillin), and 1-500 ng ml(-1) (group of penicillin). The limits of detection are 0.8 ng ml(-1), 3.9 ng ml(-1), which are lower than MRL, established for penicillin antibiotics. The sensors were tested in detecting penicillins in milk, pork, beef, liver. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Application on Gold Nanoparticles-Dotted 4-Nitrophenylazo Graphene in a Label-Free Impedimetric Deoxynivalenol Immunosensor

    Directory of Open Access Journals (Sweden)

    Christopher Edozie Sunday

    2015-02-01

    Full Text Available In this paper, we report a new concept to construct a label-free electrochemical inhibition-based immunosensor for the detection of the mycotoxin deoxynivalenol (DON in cereal samples. The electrochemical impedance spectroscopy of tris(bipyridine ruthenium (II chloride was used as a marker enhanced with gold nanoparticles-dotted 4-nitrophenylazo functionalized graphene (AuNp/G/PhNO2 nanocatalyst mediated in Nafion on a glassy carbon electrode. Under the optimized conditions, the formation of immunocomplexes inhibited electron flow and increased the charge transfer resistance of the sensing interface linearly. The change in impedance was proportional to DON concentrations in the range of 6–30 ng/mL with a sensitivity and detection limit of 32.14 ΩL/ng and 0.3 µg/mL, respectively, which compares favorably with the ELISA result. The proposed sensor had a stability of 80.3%, good precision and selectivity in DON standard solution containing different interfering agents, indicating promising application prospect for this strategy in designing impedimetric, electrochemiluminescent, voltammetric or amperometric sensors.

  20. Giant Gold Nanowire Vesicle-Based Colorimetric and SERS Dual-Mode Immunosensor for Ultrasensitive Detection of Vibrio parahemolyticus.

    Science.gov (United States)

    Guo, Zhiyong; Jia, Yaru; Song, Xinxin; Lu, Jing; Lu, Xuefei; Liu, Baoqing; Han, Jiaojiao; Huang, Youju; Zhang, Jiawei; Chen, Tao

    2018-05-15

    Conventional methods for the detection of Vibrio parahemolyticus (VP) usually need tedious, labor-intensive processes, and have low sensitivity, which further limits their practical applications. Herein, we developed a simple and efficient colorimetry and surface-enhanced Raman scattering (SERS) dual-mode immunosensor for sensitive detection of VP, by employing giant Au vesicles with anchored tiny gold nanowires (AuNW) as a smart probe. Due to the larger specific surface and special hollow structure of giant Au vesicles, silver staining would easily lead to vivid color change for colorimetric analysis and further amplify SERS signals. The t-test was further used to determine if two sets of data from colorimetry and SERS were significantly different from each other. The result shows that there was no significant difference between data from the two methods. Two sets of data can mutually validate each other and avoid false positive and negative detection. The designed colorimetry-SERS dual-mode sensor would be very promising in various applications such as food safety inspection, personal healthcare, and on-site environmental monitoring.

  1. Sustainability of uranium sources

    International Nuclear Information System (INIS)

    Prasser, Horst-Michael; Bayard, Andre-Samuel; Dones, Roberto

    2008-01-01

    Smith and Storm van Leeuwen (SSL, 2005) point out that the growth of the energy requirements for uranium mining and milling at decreasing ore grades will cause the output of the nuclear energy chain to become negative at uranium contents in the ore below 100 - 200 ppm. They conclude that an expiration of uranium will occur by 2076 in a business-as-usual scenario and by about 2050 when a 2.5 % annual growth of the consumption is assumed. The high relevance of this issue is the motivation for a detailed review of these results. The concept of a limiting ore grade was introduced by Chapman already in 1975. His model has been fitted to the performance data of the Roessing mine in Namibia operating at low grade, which makes further extrapolations more reliable. The performance data published in open literature allows quantifying the energy requirements for the removal of the waste rock separately from those for the mining of the ore, which is one of the concepts of Chapman. It is shown that the amount of waste rock to be removed per unit ore has a strong effect on the energy consumed in the mine. The limiting ore grade is much lower than the one predicted by SSL and much higher amounts of uranium are predicted for a continuation of the utilization of nuclear power. Despite of the fact that SSL cite the paper of Chapman (1975), they decide to develop an own oversimplified model based on a reciprocal proportionality of the energy requirements to the ore grade alone, which is a significant step back. SSL even cite a statement of Chapman directly, saying that the stripping ratio can influence the energy requirements of uranium mining 'by a factor of five', without drawing the right conclusions. Furthermore, neither a comparison to more recent mine data, nor any kind of an uncertainty analysis is presented. The approach of SSL must therefore be disqualified as unscientific and their results discarded. (authors)

  2. Uranium from seawater

    International Nuclear Information System (INIS)

    Gregg, D.; Folkendt, M.

    1982-01-01

    A novel process for recovering uranium from seawater is proposed and some of the critical technical parameters are evaluated. The process, in summary, consists of two different options for contacting adsorbant pellets with seawater without pumping the seawater. It is expected that this will reduce the mass handling requirements, compared to pumped seawater systems, by a factor of approximately 10 5 , which should also result in a large reduction in initial capital investment. Activated carbon, possibly in combination with a small amount of dissolved titanium hydroxide, is expected to be the preferred adsorbant material instead of the commonly assumed titanium hydroxide alone. The activated carbon, after exposure to seawater, can be stripped of uranium with an appropriate eluant (probably an acid) or can be burned for its heating value (possible in a power plant) leaving the uranium further enriched in its ash. The uranium, representing about 1% of the ash, is then a rich ore and would be recovered in a conventional manner. Experimental results have indicated that activated carbon, acting alone, is not adequately effective in adsorbing the uranium from seawater. We measured partition coefficients (concentration ratios) of approximately 10 3 in seawater instead of the reported values of 10 5 . However, preliminary tests carried out in fresh water show considerable promise for an extraction system that uses a combination of dissolved titanium hydroxide (in minute amounts) which forms an insoluble compound with the uranyl ion, and the insoluble compound then being sorbed out on activated carbon. Such a system showed partition coefficients in excess of 10 5 in fresh water. However, the system was not tested in seawater

  3. Kvanefjeld uranium project

    International Nuclear Information System (INIS)

    Erlendsson, G.; Jensen, J.; Kofoed, S.; Paulsen, J.L.

    1983-11-01

    The draft uranium project ''Kvanefjeld'' describes the establishment and operation of an industrial plant for exploiting the uranium deposit at Kvanefjeld. The draft project is part of the overall pre-feasibility project and is based on its results. The draft project includes two alternative locations for the processing plant and the tailings deposit plant. The ore reserve is estimated at 56 million tons with an average content of 365 PPM. The mine will be established as an open pit, with a slope angle of 55deg. Conventional techniques are used in drilling, blasting and handling the ore. Waste rock with no uranium content will be disposed of in two ponds near the mine. The waste rock volume is estimated at 80 million tons. A processing plant for extracting uranium from the ore will be established. The technical layout of the plant is based on the extraction experiments performed at Risoe from 1981-83. Yearly capacity is 4.2 million tons of ore. Electrical energy will be supplied from a hydroelectric station to be built at Johan Dahl Land. Thermal energy (steam/heat) will be supplied from a coal-fired district heating plant to be built in connection with the processing plant. Expected power consumption is estimated at 225 GWh/year. Heat consumption is of the same order. In the third year the plant is expected to operate at full capacity. Operating costs will be Dkr. 121/ton of ore from years 1 through 7. Consumption of chemicals will be reduced from the 7th year, and operating costs will consequently drop to Dkr. 115/ton of ore. Calculations show that industrial extraction of the uranium deposit in Kvanefjeld is economically advantageous. In addition, the economy of the project is expected to improve by extracting byproducts from the ore. (EG)

  4. Radioactivity and the French uranium bearing minerals

    International Nuclear Information System (INIS)

    Guiollard, P.Ch.; Boisson, J.M.; Leydet, J.C.; Meisser, N.

    1998-01-01

    This special issue of Regne Mineral journal is entirely devoted to the French uranium mining industry. It comprises 4 parts dealing with: the uranium mining industry in France (history, uranium rush, deposits, geologic setting, prosperity and recession, situation in 1998, ore processing); radioactivity and the uranium and its descendants (discovery, first French uranium bearing ores, discovery of radioactivity, radium and other uranium descendants, radium mines, uranium mines, atoms, elements and isotopes, uranium genesis, uranium decay, isotopes in an uranium ore, spontaneous fission, selective migration of radionuclides, radon in mines and houses, radioactivity units, radioprotection standards, new standards and controversies, natural and artificial radioactivity, hazards linked with the handling and collecting of uranium ores, conformability with radioprotection standards, radioactivity of natural uranium minerals); the French uranium bearing minerals (composition, crystal structure, reference, etymology, fluorescence). (J.S.)

  5. Precise coulometric titration of uranium in a high-purity uranium metal and in uranium compounds

    International Nuclear Information System (INIS)

    Tanaka, Tatsuhiko; Yoshimori, Takayoshi

    1975-01-01

    Uranium in uranyl nitrate, uranium trioxide and a high-purity uranium metal was assayed by the coulometric titration with biamperometric end-point detection. Uranium (VI) was reduced to uranium (IV) by solid bismuth amalgam in 5M sulfuric acid solution. The reduced uranium was reoxidized to uranium (VI) with a large excess of ferric ion at a room temperature, and the ferrous ion produced was titrated with the electrogenerated manganese(III) fluoride. In the analyses of uranium nitrate and uranium trioxide, the results were precise enough when the error from uncertainty in water content in the samples was considered. The standard sample of pure uranium metal (JAERI-U4) was assayed by the proposed method. The sample was cut into small chips of about 0.2g. Oxides on the metal surface were removed by the procedure shown by National Bureau of Standards just before weighing. The mean assay value of eleven determinations corrected for 3ppm of iron was (99.998+-0.012) % (the 95% confidence interval for the mean), with a standard deviation of 0.018%. The proposed coulometric method is simple and permits accurate and precise determination of uranium which is matrix constituent in a sample. (auth.)

  6. PRODUCTION OF URANIUM METAL BY CARBON REDUCTION

    Science.gov (United States)

    Holden, R.B.; Powers, R.M.; Blaber, O.J.

    1959-09-22

    The preparation of uranium metal by the carbon reduction of an oxide of uranium is described. In a preferred embodiment of the invention a charge composed of carbon and uranium oxide is heated to a solid mass after which it is further heated under vacuum to a temperature of about 2000 deg C to produce a fused uranium metal. Slowly ccoling the fused mass produces a dendritic structure of uranium carbide in uranium metal. Reacting the solidified charge with deionized water hydrolyzes the uranium carbide to finely divide uranium dioxide which can be separated from the coarser uranium metal by ordinary filtration methods.

  7. Uranium resource technology, Seminar 3, 1980

    International Nuclear Information System (INIS)

    Morse, J.G.

    1980-01-01

    This conference proceedings contains 20 papers and 1 panel discussion on uranium mining and ore treatment, taking into account the environmental issues surrounding uranium supply. Topics discussed include: the US uranium resource base, the technology and economics of uranium recovery from phosphate resources, trends in preleash materials handling of sandstone uranium ores, groundwater restoration after in-situ uranium leaching, mitigation of the environmental impacts of open pit and underground uranium mining, remedial actions at inactive uranium mill tailings sites, environmental laws governing in-situ solution mining of uranium, and the economics of in-situ solution mining. 16 papers are indexed separately

  8. Interpreting faecal analysis results for monitoring exposure to uranium

    International Nuclear Information System (INIS)

    Berard, P.; Rongier, E.; Faure, M.L.; Auriol, B.; Estrabaud, M.; Mazeyrat, C.

    1996-01-01

    Radiotoxicological monitoring of workers exposed to non-transferable forms of uranium requires six-monthly examinations. These examinations are prescribed according to the kind of product manipulated and tO the industrial risk attached to the workplace. The range of examinations that are useful for this kind of monitoring includes whole body counting examinations, urine analyses and in-line faecal sampling: whole body examinations, which are fundamental to monitoring, provide a lung retention value. However, the detection limit of lung examinations is not low enough for chronic operational monitoring; urine examinations are extremely sensitive to alpha activity (1 mBq per isotope) but the fraction detected in the urine after incorporation by inhalation is very small; in-line 24-hour faecal sampling allows avoiding any workplace exclusion. The authors intend to present their experience acquired over a six year period in the field of systematic faecal examinations after chronic inhalation of the different uranium compounds. They also present results of a study carried out to determine normal uranium concentrations in the faeces of a non-exposed population, the uranium content in drinking waters and the consequences on faecal excretion. Establishing the isotopic content of uranium in the faeces makes it possible to determine practical investigation levels for occupational monitoring. Even if faecal sampling may be critically perceived by the personnel, the authors' experience highlights the value of this kind of analysis which allows to track down the industrial reality of the exposure. Internal dosimetry calculations cannot, however, be carried out, because the physical parameters of the inhaled aerosols are not always known. (author)

  9. 31 CFR 540.309 - Natural uranium.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Natural uranium. 540.309 Section 540... FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.309 Natural uranium. The term natural uranium means uranium found in...

  10. Method of preparation of uranium nitride

    Science.gov (United States)

    Kiplinger, Jaqueline Loetsch; Thomson, Robert Kenneth James

    2013-07-09

    Method for producing terminal uranium nitride complexes comprising providing a suitable starting material comprising uranium; oxidizing the starting material with a suitable oxidant to produce one or more uranium(IV)-azide complexes; and, sufficiently irradiating the uranium(IV)-azide complexes to produce the terminal uranium nitride complexes.

  11. The French natural uranium industry in 1986

    International Nuclear Information System (INIS)

    Baron, Marcel

    1987-01-01

    France has relatively large uranium deposits. This led to the creation of an internationally significant uranium mining industry. The structure of this industry is explained. In 1985 world supply of uranium was greater than world demand leading to an increase in uranium stocks. However, as demand is expected to increase, the industry is undertaking extensive uranium exploration, mainly abroad. (UK)

  12. Resolution in in-line digital holography

    International Nuclear Information System (INIS)

    Fournier, C; Denis, L; Fournel, T

    2010-01-01

    Digital in-line holography is a 3D imaging technique which has been widely developed during the last two decades. This technique achieves the 3D reconstruction of volume objects from a 2D image-hologram. It is a metrological tool and therefore the improvement of resolution is one of the current challenges. However the resolution depends on several experimental parameters and the experimenters have to choose the parameters which will lead to the best resolution. This paper presents the study of resolution in in-line digital holography from the asymptotical bounds of the covariance of estimators used in hologram reconstruction.

  13. A disposable electrochemical immunosensor arrays using 4-channel screen-printed carbon electrode for simultaneous detection of Escherichia coli O157:H7 and Enterobacter sakazakii

    International Nuclear Information System (INIS)

    Dou, Wenchao; Tang, Weilu; Zhao, Guangying

    2013-01-01

    An electrochemical immunosensor for Escherichia coli O157:H7 (E. coli O157:H7) and Enterobacter sakazakii (E. sakazakii) detection using carbon screen-printed low-density arrays is reported. The sensors were fabricated based on screen-printed carbon arrays containing four carbon working electrode, an integrated carbon counter electrodes and an integrated Ag/AgCl reference electrode. Multi-walled carbon nanotubes (MWCNTs)/sodium alginate (SA)/carboxymethyl chitosan (CMC) composite films were coated on all the working electrodes to enhance the sensitization of the electrode. Horseradish peroxidases (HRP) labeled antibodies of two bacteria were immobilize on different working electrode of the same screen-printed electrode respectively. The immobilization of MWCNTs, HRP labeled antibodies onto the screen-printed carbon electrodes was examined using atom force microscopy (AFM) and cyclic voltammetry (CV). The analytical performance of proposed immunosensor arrays toward E. sakazakii and E. coli O157:H7 was investigated by AFM and CV. Under optimal conditions, the linear range of E. sakazakii and E. coli O157:H7 were from 10 4 to 10 10 cfu/ml, with a detection limit of 4.57 × 10 3 cfu/ml (S/N = 3) and 3.27 × 10 3 cfu/ml (S/N = 3), respectively. The specificity, reproducibility, stability and accuracy of the proposed immunosensor arrays were also evaluated. Two antibodies modified work electrodes were tested and compared in terms of sensitivity and ability to recognize different pathogenic biological species

  14. Amperometric carbohydrate antigen 19-9 immunosensor based on three dimensional ordered macroporous magnetic Au film coupling direct electrochemistry of horseradish peroxidase

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Qi [College of Sciences, Nanjing Tech University, Nanjing 211816 (China); Chen, Xiaojun, E-mail: chenxj_njut@126.com [College of Sciences, Nanjing Tech University, Nanjing 211816 (China); State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 210009 (China); Tang, Yin [Zhangjiagang Hospital of Traditional Chinese Medicine, Zhangjiagang 215600 (China); Ge, Lingna; Guo, Buhua [College of Sciences, Nanjing Tech University, Nanjing 211816 (China); Yao, Cheng, E-mail: yaochengnjut@163.com [College of Sciences, Nanjing Tech University, Nanjing 211816 (China)

    2014-03-01

    Highlights: • Three dimensional ordered macroporous magnetic electrode was newly used in electrochemical immunosensor. • The large surface area of macroporous magnetic electrode could improve the immobilized amount of antibody. • Au nanoparticles functionalized SBA-15 was used to immobilize enzyme labeled Ab₂ and enzyme. • Macroporous magnetic electrode and Au nanoparticles composite facilitated the direct electron transfer of enzyme. • The immunoassay avoided adding electron transfer mediator, simplifying the procedure. Abstract: A sandwich-type electrochemical immunosensor for the detection of carbohydrate antigen 19-9 (CA 19-9) antigen based on the immobilization of primary antibody (Ab₁) on three dimensional ordered macroporous magnetic (3DOMM) electrode, and the direct electrochemistry of horseradish peroxidase (HRP) that was used as both the label of secondary antibody (Ab₂) and the blocking reagent. The 3DOMM electrode was fabricated by introducing core–shell Au–SiO₂@Fe₃O₄ nanospheres onto the surface of three dimensional ordered macroporous (3DOM) Au electrode via the application of an external magnet. Au nanoparticles functionalized SBA-15 (Au@SBA-15) was conjugated to the HRP labeled secondary antibody (HRP-Ab₂) through the Au–SH or Au–NH₃⁺ interaction, and HRP was also used as the block reagent. The formation of antigen–antibody complex made the combination of Au@SBA-15 and 3DOMM exhibit remarkable synergistic effects for accelerating direct electron transfer (DET) between HRP and the electrode. Under the optimal conditions, the DET current signal increased proportionally to CA 19-9 concentration in the range of 0.05 to 15.65 U mL⁻¹ with a detection limit of 0.01 U mL⁻¹. Moreover, the immunosensor showed high selectivity, good stability, satisfactory reproducibility and regeneration. Importantly, the developed method was used to assay clinical serum specimens, achieving a good relation with those obtained from

  15. Electrochemical immunosensor assay (EIA) for sensitive detection of E. coli O157:H7 with signal amplification on a SG-PEDOT-AuNPs electrode interface.

    Science.gov (United States)

    Guo, Yuna; Wang, Yu; Liu, Su; Yu, Jinghua; Wang, Hongzhi; Cui, Min; Huang, Jiadong

    2015-01-21

    A novel electrochemical immunosensor assay (EIA) for highly sensitive and specific detection of Escherichia coli O157:H7 has been developed. This immunosensor is constructed by the assembly of capture antibody on SG-PEDOT-AuNPs composites modified glass carbon electrode. In the presence of target E. coli O157:H7, horseradish peroxidase (HRP)-labeled antibody is captured on the electrode surface to form a sandwich-type system via the specific identification. As a result, E. coli O157:H7 detection is realized by outputting a redox current from electro-reduction of hydrogen peroxide reaction catalyzed by HRP. In our assay, the combination of the unique properties of sulfonated graphene (SG) and gold nanoparticles (AuNPs) can not only accelerate electron transfer on electrode interface, but also provide an excellent scaffold for the conjugation of capture antibody that significantly improves the target capture efficiency and enhances the sensitivity of the biosensor. The results reveal the calibration plot obtained for E. coli O157:H7 is approximately linear from 7.8 × 10-7.8 × 10(6) colony-forming unit (cfu) mL(-1) with the limit of detection of 3.4 × 10 cfu mL(-1). In addition, the biosensor has been successfully applied to the quantitative assay of E. coli O157:H7 in synthetic samples (spring water and milk). Hence, the developed electrochemical-based immunosensor might provide a useful and practical tool for E. coli O157:H7 determination and related food safety analysis and clinical diagnosis.

  16. A sandwich-type electrochemical immunosensor based on in situ silver deposition for determination of serum level of HER2 in breast cancer patients.

    Science.gov (United States)

    Shamsipur, Mojtaba; Emami, Mahdi; Farzin, Leila; Saber, Reza

    2018-04-30

    The sensitive quantification of Human Epidermal growth factor Receptor 2 (HER2), as a key prognostic tumor marker, plays a critical role in screening, early diagnosis and management of breast cancer. This paper describes a sandwich-type immunoassay with silver signal enhancement strategy for highly sensitive detection of HER2. For this purpose, the target capturing step was designed by functionalization of 3-aminopropyltrimethoxysilane coated magnetite nanoparticles with antibody (antiHER2/APTMS-Fe 3 O 4 ), as a platform bioconjugate (PB), and immobilized at a bare GCE. Then, in the presence of label-free immunosensor, the PB was covered by magnetic gold nanoparticles self-assembled with thiolated antibodies (antiHER2/Hyd@AuNPs-APTMS-Fe 3 O 4 ) containing chemically reduced silver ions, as a label bioconjugate (LB). Under optimum conditions, a linear relationship between the differential pulse voltammetric (DPV) stripping signal of silver and the logarithm of HER2 concentrations was obtained in the range of 5.0 × 10 -4 -50.0ngmL -1 (R 2 = 0.9906) with a detection limit of 2.0 × 10 -5 ngmL -1 . The effectiveness of this protocol was evaluated experimentally through employing of designed immunosensor for detection of the serum level of tumor marker. The good consistency of the results with those obtained by the enzyme-linked immunosorbent assay (ELISA) conventional method (p-value of < 0.05) showed that this immunosensor can be applied for the testing of HER2 in clinical samples of breast cancer patients. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. New approach for monitoring fish stress: A novel enzyme-functionalized label-free immunosensor system for detecting cortisol levels in fish.

    Science.gov (United States)

    Wu, Haiyun; Ohnuki, Hitoshi; Ota, Shirei; Murata, Masataka; Yoshiura, Yasutoshi; Endo, Hideaki

    2017-07-15

    Fishes display a wide variation in their physiological responses to stress, which is clearly evident in the plasma corticosteroid changes, chiefly cortisol levels in fish. As a well-known indicator of fish stress, a simple and rapid method for detecting cortisol changes especially sudden increases is desired. In this study, we describe an enzyme-functionalized label-free immunosensor system for detecting fish cortisol levels. Detection of cortisol using amperometry was achieved by immobilizing both anti-cortisol antibody (selective detection of cortisol) and glucose oxidase (signal amplification and non-toxic measurement) on an Au electrode surface with a self-assembled monolayer. This system is based on the maximum glucose oxidation output current change induced by the generation of a non-conductive antigen-antibody complex, which depends on the levels of cortisol in the sample. The immunosensor responded to cortisol levels with a linear decrease in the current in the range of 1.25-200ngml -1 (R=0.964). Since the dynamic range of the sensor can cover the normal range of plasma cortisol in fish, the samples obtained from the fish did not need to be diluted. Further, electrochemical measurement of one sample required only ~30min. The sensor system was applied to determine the cortisol levels in plasma sampled from Nile tilapia (Oreochromis niloticus), which were then compared with levels of the same samples determined using the conventional method (ELISA). Values determined using both methods were well correlated. These findings suggest that the proposed label-free immunosensor could be useful for rapid and convenient analysis of cortisol levels in fish without sample dilution. We also believe that the proposed system could be integrated in a miniaturized potentiostat for point-of-care cortisol detection and useful as a portable diagnostic in fish farms in the future. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Uranium and environment in Kazakstan

    International Nuclear Information System (INIS)

    Fyodorov, G.; Bayadilov, E.; Zhelnov, V.; Akhmetov, M.; Abakumov, A.

    1997-01-01

    Kazakstan's data on uranium as a state report has been included for the first time in the Red Book. Therefore the report contains two large themes presented in Suggested Topics for Papers: Country report, based on the 1995 NEA/IAEA Red Book Questionnaire and environmental impact regulations. Kazakstan is considered as one of the world leaders on uranium supply. In Kazakstan there are many well known types of deposits but the main one is the sandstone-rollfront type. That type is represented by the group of deposits of the Syr-Darya uranium ore province. Deposits of that type include that main part of uranium ore of the Republic of Kazakstan and supply almost all of its uranium mining. At the large three enterprises the uranium is extracted by underground leaching. The mining method of uranium extraction is stopped. Because of the poor development of nuclear energy, Kazakstan's need for uranium is not very high. Presence of a large amount of cheap and technological uranium ores allow the Republic to export uranium. There are plans to increase uranium mining and perhaps to establish new mining facilities including joint-ventures. More than 50 uranium deposits are known in Kazakstan. During prospecting and exploitation of these deposits a large amount of rad wastes in the form of ore dumps and tailings were generated. They have a substantial influence on the environment. Moreover, near the sandstone-rollfront type uranium deposits the large amount of underground water has been contaminated by radionuclides. Special investigation of this phenomenon is necessary. In Kazakstan there are the rad waste disposal conception and contaminated earth recultivation regulations. At present ''The Rad Wastes Management Law'' is submitted for approval. (author). 2 figs

  19. Recovery of uranium from uranium bearing black shale

    International Nuclear Information System (INIS)

    Das, Amrita; Yadav, Manoj; Singh, Ajay K.

    2016-01-01

    Black shale is the unconventional resource of uranium. Recovery of uranium from black shale has been carried out by the following steps: i) size reduction, ii) leaching of uranium in the aqueous medium, iii) fluoride ion removal, iv) solvent extraction of uranium from the aqueous leach solution, v) scrubbing of the loaded solvent after extraction to remove impurities as much as possible and vi) stripping of uranium from the loaded organic into the aqueous phase. Leaching of black shale has been carried out in hydrochloric acid. Free acidity of the leach solution has been determined by potentiometric titration method. Removal of fluoride ions has been done using sodium chloride. Solvent extraction has been carried out by both tributyl phosphate and alamine-336 as extractants. Scrubbing has been tried with oxalic acid and sulphuric acid. Stripping with sodium carbonate solution has been carried out. Overall recovery of uranium is 95%. (author)

  20. Uranium complex recycling method of purifying uranium liquors

    International Nuclear Information System (INIS)

    Elikan, L.; Lyon, W.L.; Sundar, P.S.

    1976-01-01

    Uranium is separated from contaminating cations in an aqueous liquor containing uranyl ions. The liquor is mixed with sufficient recycled uranium complex to raise the weight ratio of uranium to said cations preferably to at least about three. The liquor is then extracted with at least enough non-interfering, water-immiscible, organic solvent to theoretically extract about all of the uranium in the liquor. The organic solvent contains a reagent which reacts with the uranyl ions to form a complex soluble in the solvent. If the aqueous liquor is acidic, the organic solvent is then scrubbed with water. The organic solvent is stripped with a solution containing at least enough ammonium carbonate to precipitate the uranium complex. A portion of the uranium complex is recycled and the remainder can be collected and calcined to produce U 3 O 8 or UO 2