WorldWideScience

Sample records for gold 190

  1. The use of 190Au and 110Ag radioisotopes in the study of gold and silver extraction by some thiophosphates

    International Nuclear Information System (INIS)

    Babaev, B.N.; Dalimov, D.N.; Gafurova, R.N.; Kadyrova, D.M.; Abdullaeva, L.K.; Abdurakhmanova, U.K.; Ganiev, A.G.; Rakhimov, Kh.R.

    1997-01-01

    The method of labelled atoms(silver 110 and gold 190) was used for study of extraction properties of different derivatives of thiophosphoric acids. The study have shown that the extraction effectiveness depends both on matter structure and on ph value of medium and type of acid used. (A.A.D.)

  2. 49 CFR 190.209 - Response options.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Response options. 190.209 Section 190.209 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... PROCEDURES Enforcement § 190.209 Response options. Within 30 days of receipt of a notice of probable...

  3. 46 CFR 190.01-1 - Application.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Application. 190.01-1 Section 190.01-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS CONSTRUCTION AND ARRANGEMENT Hull Structure § 190.01-1 Application. (a) The provisions of this subpart, with the exception of...

  4. 46 CFR 190.05-1 - Application.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Application. 190.05-1 Section 190.05-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS CONSTRUCTION AND ARRANGEMENT General Fire Protection § 190.05-1 Application. (a) The provisions of this subpart shall apply to...

  5. 46 CFR 190.25-1 - Application.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Application. 190.25-1 Section 190.25-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS CONSTRUCTION AND ARRANGEMENT Rails and Guards § 190.25-1 Application. (a) The provisions of this subpart with the exception of...

  6. 46 CFR 190.10-1 - Application.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Application. 190.10-1 Section 190.10-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS CONSTRUCTION AND ARRANGEMENT Means of Escape § 190.10-1 Application. (a) The provisions of this subpart, with the exception of...

  7. 46 CFR 190.15-1 - Application.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Application. 190.15-1 Section 190.15-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS CONSTRUCTION AND ARRANGEMENT Ventilation § 190.15-1 Application. (a) The provisions of this subpart, with the exception of...

  8. 46 CFR 190.20-1 - Application.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Application. 190.20-1 Section 190.20-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS CONSTRUCTION AND ARRANGEMENT Accomodations for Officers, Crew, and Scientific Personnel § 190.20-1 Application. (a) Except as...

  9. 46 CFR 190.07-1 - Application.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Application. 190.07-1 Section 190.07-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS CONSTRUCTION AND ARRANGEMENT Structural Fire Protection § 190.07-1 Application. (a) The provisions of this subpart, with the...

  10. 46 CFR 190.10-10 - Location.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Location. 190.10-10 Section 190.10-10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS CONSTRUCTION AND ARRANGEMENT Means of Escape § 190.10-10 Location. (a) The two means of escape shall be as remote as...

  11. 21 CFR 1271.190 - Facilities.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Facilities. 1271.190 Section 1271.190 Food and... CELLULAR AND TISSUE-BASED PRODUCTS Current Good Tissue Practice § 1271.190 Facilities. (a) General. Any facility used in the manufacture of HCT/Ps must be of suitable size, construction, and location to prevent...

  12. 21 CFR 137.190 - Cracked wheat.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Cracked wheat. 137.190 Section 137.190 Food and... Related Products § 137.190 Cracked wheat. Cracked wheat is the food prepared by so cracking or cutting into angular fragments cleaned wheat other than durum wheat and red durum wheat that, when tested by...

  13. 7 CFR 65.190 - Lamb.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Lamb. 65.190 Section 65.190 Agriculture Regulations of..., PORK, LAMB, CHICKEN, GOAT MEAT, PERISHABLE AGRICULTURAL COMMODITIES, MACADAMIA NUTS, PECANS, PEANUTS, AND GINSENG General Provisions Definitions § 65.190 Lamb. Lamb means meat produced from sheep. ...

  14. 46 CFR 190.07-10 - Construction.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Construction. 190.07-10 Section 190.07-10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS CONSTRUCTION AND ARRANGEMENT Structural Fire Protection § 190.07-10 Construction. (a) The hull, superstructure, structural...

  15. 46 CFR 190.20-15 - Construction.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Construction. 190.20-15 Section 190.20-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS CONSTRUCTION AND ARRANGEMENT Accomodations for Officers, Crew, and Scientific Personnel § 190.20-15 Construction. All crew...

  16. 21 CFR 145.190 - Canned prunes.

    Science.gov (United States)

    2010-04-01

    ... of a mixture of brown sugar and honey, an appropriate statement would be “___ sirup of brown sugar... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Canned prunes. 145.190 Section 145.190 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN...

  17. 40 CFR 190.02 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... materials from -the cycle. (c) General environment means the total terrestrial, atmospheric and aquatic... of the public means any individual that can receive a radiation dose in the general environment... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Definitions. 190.02 Section 190.02...

  18. 38 CFR 52.190 - Infection control.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false Infection control. 52.190... FOR ADULT DAY HEALTH CARE OF VETERANS IN STATE HOMES Standards § 52.190 Infection control. The program management must establish and maintain an infection control program designed to prevent the development and...

  19. 38 CFR 51.190 - Infection control.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false Infection control. 51.190... FOR NURSING HOME CARE OF VETERANS IN STATE HOMES Standards § 51.190 Infection control. The facility management must establish and maintain an infection control program designed to provide a safe, sanitary, and...

  20. 40 CFR 68.190 - Updates.

    Science.gov (United States)

    2010-07-01

    ... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CHEMICAL ACCIDENT PREVENTION PROVISIONS Risk Management Plan § 68.190 Updates. (a) The owner or operator shall... later than the date on which a new regulated substance is first present in an already covered process...

  1. 49 CFR 190.323 - Consideration of comments received.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Consideration of comments received. 190.323 Section 190.323 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND... SAFETY PROGRAMS AND RULEMAKING PROCEDURES Procedures for Adoption of Rules § 190.323 Consideration of...

  2. 46 CFR 190.01-15 - Special consideration.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Special consideration. 190.01-15 Section 190.01-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS CONSTRUCTION AND ARRANGEMENT Hull Structure § 190.01-15 Special consideration. (a) Special consideration will...

  3. 46 CFR 190.10-35 - Public spaces.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Public spaces. 190.10-35 Section 190.10-35 Shipping... ARRANGEMENT Means of Escape § 190.10-35 Public spaces. (a) In all cases, public spaces having a deck area of... different corridors, rooms, or spaces to minimize the possibility of one incident blocking both exits. ...

  4. 21 CFR 160.190 - Frozen egg yolks.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Frozen egg yolks. 160.190 Section 160.190 Food and... CONSUMPTION EGGS AND EGG PRODUCTS Requirements for Specific Standardized Eggs and Egg Products § 160.190 Frozen egg yolks. (a) Frozen egg yolks, frozen yolks is the food prepared by freezing egg yolks that...

  5. 46 CFR 190.20-35 - Hospital space.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Hospital space. 190.20-35 Section 190.20-35 Shipping... ARRANGEMENT Accomodations for Officers, Crew, and Scientific Personnel § 190.20-35 Hospital space. (a) Except... or more, must be provided with a hospital space. This space must be situated with regard to the...

  6. 46 CFR 190.20-50 - Heating and cooling.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Heating and cooling. 190.20-50 Section 190.20-50... CONSTRUCTION AND ARRANGEMENT Accomodations for Officers, Crew, and Scientific Personnel § 190.20-50 Heating and... the space. (b) Radiators and other heating apparatus must be so placed and shielded, where necessary...

  7. 23 CFR 190.3 - Agreement to control advertising.

    Science.gov (United States)

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Agreement to control advertising. 190.3 Section 190.3... FOR CONTROLLING OUTDOOR ADVERTISING ON THE INTERSTATE SYSTEM § 190.3 Agreement to control advertising... control outdoor advertising. It must fulfill, and must continue to fulfill its obligations under such...

  8. 21 CFR 1.90 - Notice of sampling.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Notice of sampling. 1.90 Section 1.90 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL GENERAL ENFORCEMENT REGULATIONS Imports and Exports § 1.90 Notice of sampling. When a sample of an article offered for import has...

  9. 46 CFR 190.25-10 - Storm rails.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Storm rails. 190.25-10 Section 190.25-10 Shipping COAST... ARRANGEMENT Rails and Guards § 190.25-10 Storm rails. (a) On vessels in ocean and coastwise service, suitable storm rails shall be installed in all passageways and at the deckhouse sides where persons on board...

  10. Gold prices

    OpenAIRE

    Joseph G. Haubrich

    1998-01-01

    The price of gold commands attention because it serves as an indicator of general price stability or inflation. But gold is also a commodity, used in jewelry and by industry, so demand and supply affect its pricing and need to be considered when gold is a factor in monetary policy decisions.

  11. Analysis list: Cp190 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Cp190 Cell line,Embryo,Larvae + dm3 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/...target/Cp190.1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/target/Cp190.5.tsv http://dbarchive.bioscience...dbc.jp/kyushu-u/dm3/target/Cp190.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/colo/Cp190.Cell_l...ine.tsv,http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/colo/Cp190.Embryo.tsv,http://dbarchive.bioscience...dbc.jp/kyushu-u/dm3/colo/Cp190.Larvae.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/

  12. Final report for the 190-D complex decontamination and decommissioning

    International Nuclear Information System (INIS)

    Thoren, S.D.

    1996-09-01

    This report documents the decontamination and decommissioning (D ampersand D) of the 190-D complex. (located on the Hanford Site in Richland, Washington). D ampersand D of the 190-D complex included decontaminating and removing hazardous and radiologically contaminated materials; dismantling equipment piping and utility infrastructure; demolishing the structure; and restoring the site. The 100-D Area contains two of the nine inactive plutonium production reactors. The reactor sites are located along the south shore of the Columbia River where the sites cover the northern part of the Hanford Site. The 190-D complex is located in the 100-D Area and is composed of the following seven buildings: 185-D De-aeration Building, 189-D Refrigeration Building, 190-D Tank Room Highbay, 190-D Process Pump Room, 190-DA Process Pump Room Annex, 195-D Vertical Safety Rod Test Tower, 1724-D Underwater Test Facility

  13. Gold Returns

    OpenAIRE

    Robert J. Barro; Sanjay P. Misra

    2013-01-01

    From 1836 to 2011, the average real rate of price change for gold in the United States is 1.1% per year and the standard deviation is 13.1%, implying a one-standard-deviation confidence band for the mean of (0.1%, 2.1%). The covariances of gold's real rate of price change with consumption and GDP growth rates are small and statistically insignificantly different from zero. These negligible covariances suggest that gold's expected real rate of return--which includes an unobserved dividend yiel...

  14. Gold monetization and gold discipline

    OpenAIRE

    Robert P. Flood; Peter M. Garber

    1981-01-01

    The paper is a study of the price level and relative price effects of a policy to monetize gold and fix its price at a given future time and at the then prevailing nominal price. Price movements are analyzed both during the transition to the gold standard and during the post-monetization period. The paper also explores the adjustments to fiat money which are necessary to ensure that this type of gold monetization is non-inflationary. Finally, some conditions which produce a run on the governm...

  15. Nuclear shape transition in light gold isotopes

    International Nuclear Information System (INIS)

    Wallmeroth, K.; Bollen, G.; Dohn, A.; Egelhof, P.; Kroenert, U.; Heyde, K.; Coster, C. de; Wood, J.L.; Kluge, H.J.; European Organization for Nuclear Research, Geneva; European Organization for Nuclear Research, Geneva

    1989-01-01

    The hyperfine structure and isotope shifts of short-lived gold isotopes with 185≤A≤190 and the 11/2 - isomer of 189 Au have been investigated by application of on-line resonance ionization mass spectroscopy. A detection efficiency of ε=10 -8 for gold atoms was observed at a background of about one event per 1000 laser shots. The deduced charge radii show a drastic change between A=187 and A=186 which is interpreted as an onset of strong deformation (β 2 ≅ 0.25) in 186 Au and 185 Au due to the influence of the π1h 9/2 intruder orbital. (orig.)

  16. 17 CFR 256.190 - Accumulated deferred income taxes.

    Science.gov (United States)

    2010-04-01

    .... proprietary capital ... (CONTINUED) UNIFORM SYSTEM OF ACCOUNTS FOR MUTUAL SERVICE COMPANIES AND SUBSIDIARY SERVICE COMPANIES, PUBLIC UTILITY HOLDING COMPANY ACT OF 1935 4. Deferred Debits § 256.190 Accumulated deferred income taxes. (a...

  17. Gold Museum

    OpenAIRE

    Efraín Sánchez Cabra

    2003-01-01

    On 22 december 1939, the Banco de la República, the Central Bank of Colombia, purchased a 23.5 centimetres high pre-Columbian gold arte fact weighing 777·7 grams that was to become the Gold M useum's foundation stone. Described as a Quimbaya poporo, it is a masterpiece of pre-Hispanic goldwork, an object of beauty whose brightly burnished body and neck, crowned with four sphere-like or naments, rest on an exquisite cast metal tiligree base and which seems to ftoat in a space of its own. The b...

  18. Green Gold

    International Nuclear Information System (INIS)

    Salamandra Martinez, Carlos

    2004-01-01

    The main purpose of this work is to offer a general panoramic of the processes or experiences pilot that are carried out in the Project Green Gold, as strategy of environmental sustainability and organizational invigoration in Choco, especially in the 12 communities of the municipalities of Tado and Condoto. It is also sought to offer a minimum of information on the techniques of handmade production and to show the possibilities to carry out in a rational way the use and use of the natural resources. The Project Green Gold is carried out by the Corporation Green Gold (COV) and co-financed with resources of international and national character, the intervention of the financial resources it achievement mainly for the use of clean processes in the extraction stages and metals benefit. The project is centered primarily in the absence of use of products or toxic substances as the mercury, fair trade, organizational invigoration, execution of 11 approaches and certification of the metals Gold and Platinum. The COV, it has come executing the proposal from the year 2001 with the premise of contributing to the balance between the rational exploitation of the natural resources and the conservation of the environment in the Choco. In the project they are used technical handmade characteristic of the region framed inside the mining activity and production activities are diversified in the productive family units. Those producing with the support of entities of juridical character, specify the necessary game rules for the extraction and products commercialization

  19. Determination of gold in gold ores

    International Nuclear Information System (INIS)

    Keedy, C.R.; Parson, L.; Shen, J.

    1989-01-01

    The gold content of placer gold flakes and gold bearing ores was determined by instrumental and radiochemical neutron activation analysis, respectively. It was discovered that significant errors result in the instrumental method for gold flakes as small as 10 mg due to sample self-absorption of neutrons during irradiation. Reliable results were obtained for both ore samples and gold flakes by dissolving the samples in aqua regia prior to irradiation. (author) 7 refs.; 3 tabs

  20. 27 CFR 9.190 - Red Hill Douglas County, Oregon.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Red Hill Douglas County... Areas § 9.190 Red Hill Douglas County, Oregon. (a) Name. The name of the viticultural area described in this section is “Red Hill Douglas County, Oregon”. For purposes of part 4 of this chapter, “Red Hill...

  1. Phenotype-gene: 190 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available 190 http://metadb.riken.jp/db/SciNetS_ria224i/cria224u3ria224u1188i decreased responsivity under influence...:471-81. http://metadb.riken.jp/db/SciNetS_ria224i/cria224u4ria224u18263776i decreased responsivity under influence

  2. 17 CFR 190.07 - Calculation of allowed net equity.

    Science.gov (United States)

    2010-04-01

    ...; and (iii) The current realizable market value, determined as of the close of the market on the last... 17 Commodity and Securities Exchanges 1 2010-04-01 2010-04-01 false Calculation of allowed net... BANKRUPTCY § 190.07 Calculation of allowed net equity. Allowed net equity shall be computed as follows: (a...

  3. 23 CFR 190.5 - Bonus project claims.

    Science.gov (United States)

    2010-04-01

    ... which advertising controls are in effect. The eligible system mileage reported in subsequent projects on... CONTROLLING OUTDOOR ADVERTISING ON THE INTERSTATE SYSTEM § 190.5 Bonus project claims. (a) The State may claim payment by submitting a form PR-20 voucher, supported by strip maps which identify advertising control...

  4. 49 CFR 190.233 - Corrective action orders.

    Science.gov (United States)

    2010-10-01

    ... effective, the Associate Administrator, OPS may request the Attorney General to bring an action for appropriate relief in accordance with § 190.235. (i) Upon petition by the Attorney General, the District... must notify the Associate Administrator, OPS of that election in writing within 10 days of service of...

  5. 28 CFR 0.190 - Changes within organizational units.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Changes within organizational units. 0... JUSTICE Sections and Subunits § 0.190 Changes within organizational units. (a) The head of each Office... termination of major functions within his organizational unit as he may deem necessary or appropriate. In each...

  6. 190-C Facility <90 Day Storage Pad training plan

    International Nuclear Information System (INIS)

    Little, N.C.

    1996-12-01

    This is the Environmental Restoration Contractor (ERC) team training plan for the 190-C Facility <90 Day Storage Pad of Hazardous Waste. It is intended to meet the requirements of Washington Administrative Code (WAC) 173-303-330 and the Hanford Dangerous Waste Permit. Training unrelated to compliance with WAC 173-303-330 is not addressed in this training plan. WAC 173-303-330(1)(d)(ii, v, vi) requires that personnel be familiarized, where applicable, with waste feed cut-off systems, response to ground-water contamination incidents, and shutdown of operations. These are not applicable to 190-C Facility <90 Day Storage Pad, and are therefore not covered in this training plan

  7. Review of the technical bases of 40 CFR Part 190.

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, John E.; McMahon, Kevin A.; Siegel, Malcolm Dean; Weiner, Ruth F.; Bixler, Nathan E.; Klein, Keith A. (Longenecker and Associates)

    2010-07-01

    The dose limits for emissions from the nuclear fuel cycle were established by the Environmental Protection Agency in 40 CFR Part 190 in 1977. These limits were based on assumptions regarding the growth of nuclear power and the technical capabilities of decontamination systems as well as the then-current knowledge of atmospheric dispersion and the biological effects of ionizing radiation. In the more than thirty years since the adoption of the limits, much has changed with respect to the scale of nuclear energy deployment in the United States and the scientific knowledge associated with modeling health effects from radioactivity release. Sandia National Laboratories conducted a study to examine and understand the methodologies and technical bases of 40 CFR 190 and also to determine if the conclusions of the earlier work would be different today given the current projected growth of nuclear power and the advances in scientific understanding. This report documents the results of that work.

  8. Systematic description of superdeformed bands in the mass-190 region

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yang; Guidry, M. [Oak Ridge National Lab., TN (United States)]|[Univ. of Tennessee, Knoxville, TN (United States); Zhang, Jing-ye [Univ. of Tennessee, Knoxville, TN (United States)

    1996-12-31

    Superdeformed bands for the mass-190 region are described by the Projected Shell Model. Even-even, odd mass and odd-odd nuclei are equally well described. Good agreement with available data for all isotopes studied is obtained. The authors calculation of electromagnetic properties and pairing correlations provides an understanding of the observed gradual increase of dynamical moments of inertia with angular momentum observed in many bands in this mass region.

  9. 42 CFR 415.190 - Conditions of payment: Assistants at surgery in teaching hospitals.

    Science.gov (United States)

    2010-10-01

    ... teaching hospitals. 415.190 Section 415.190 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES... PROVIDERS, SUPERVISING PHYSICIANS IN TEACHING SETTINGS, AND RESIDENTS IN CERTAIN SETTINGS Physician Services in Teaching Settings § 415.190 Conditions of payment: Assistants at surgery in teaching hospitals. (a...

  10. Superdeformation in the A=150 and A=190 regions

    International Nuclear Information System (INIS)

    Carpenter, M. P.; Janssens, R. V. F.

    1999-01-01

    Superdeformation has been established for over a decade in the mass 150 region and nearly as long in the A=190 region. The first measurements directed at nuclei in these regions concentrated on mapping out the superdeformed (SD) islands by identifying SD rotational bands in γ-ray coincidence data. These early studies provided new insights into the physics of superdeformation, but also raised unexpected issues. The new gamma-ray arrays (Gammasphere, Eurogam/Euroball and Gasp) have provided a wealth of new data on properties of SD states in these two mass regions. This paper highlights some of the more recent results from the large arrays which have addressed the outstanding issues in the field, namely, ΔI=4 staggering, identical bands, SD vibrational bands, and questions about the feeding into and the decay out of the SD well. (c) 1999 American Institute of Physics

  11. Superdeformation in the A=150 and A=190 regions

    International Nuclear Information System (INIS)

    Carpenter, M. P.

    1998-01-01

    Superdeformation has been established for over a decade in the mass 150 region and nearly as long in the A=190 region. The first measurements directed at nuclei in these regions concentrated on mapping out the superdeformed (SD) islands by identifying SD rotational bands in γ-ray coincidence data. These early studies provided new insights into the physics of superdeformation, but also raised unexpected issues. The new gamma-ray arrays (Gammasphere, Eurogam/Euroball and Gasp) have provided a wealth of new data on properties of SD states in these two mass regions. This paper highlights some of the more recent results from the large arrays which have addressed the outstanding issues in the field, namely, ΔI = 4 staggering, identical bands, SD vibrational bands, and questions about the feeding into and the decay out of the SD well

  12. Superdeformation in the A=150 and A=190 regions.

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, M. P.

    1998-12-01

    Superdeformation has been established for over a decade in the mass 150 region and nearly as long in the A=190 region. The first measurements directed at nuclei in these regions concentrated on mapping out the superdeformed (SD) islands by identifying SD rotational bands in {gamma}-ray coincidence data. These early studies provided new insights into the physics of superdeformation, but also raised unexpected issues. The new gamma-ray arrays (Gammasphere, Eurogam/Euroball and Gasp) have provided a wealth of new data on properties of SD states in these two mass regions. This paper highlights some of the more recent results from the large arrays which have addressed the outstanding issues in the field, namely, {Delta}I = 4 staggering, identical bands, SD vibrational bands, and questions about the feeding into and the decay out of the SD well.

  13. Frontiers in Gold Chemistry

    OpenAIRE

    Ahmed A. Mohamed

    2015-01-01

    Basic chemistry of gold tells us that it can bond to sulfur, phosphorous, nitrogen, and oxygen donor ligands. The Frontiers in Gold Chemistry Special Issue covers gold complexes bonded to the different donors and their fascinating applications. This issue covers both basic chemistry studies of gold complexes and their contemporary applications in medicine, materials chemistry, and optical sensors. There is a strong belief that aurophilicity plays a major role in the unending applications of g...

  14. Gold in plants

    International Nuclear Information System (INIS)

    Girling, C.A.; Peterson, P.J.

    1980-01-01

    Many plants have the ability to take up gold from the soil and to accumulate it in their tisssue. Advances have been made in understanding these processes to the point where their exploitation in the field of prospecting for gold appears practically feasible. Neutron activation analysis is used for the determination of the small quantities of gold in plants

  15. P190B RhoGAP Regulates Chromosome Segregation in Cancer Cells

    International Nuclear Information System (INIS)

    Hwang, Melissa; Peddibhotla, Sirisha; McHenry, Peter; Chang, Peggy; Yochum, Zachary; Park, Ko Un; Sears, James Cooper; Vargo-Gogola, Tracy

    2012-01-01

    Rho GTPases are overexpressed and hyperactivated in many cancers, including breast cancer. Rho proteins, as well as their regulators and effectors, have been implicated in mitosis, and their altered expression promotes mitotic defects and aneuploidy. Previously, we demonstrated that p190B Rho GTPase activating protein (RhoGAP) deficiency inhibits ErbB2-induced mammary tumor formation in mice. Here we describe a novel role for p190B as a regulator of mitosis. We found that p190B localized to centrosomes during interphase and mitosis, and that it is differentially phosphorylated during mitosis. Knockdown of p190B expression in MCF-7 and Hela cells increased the incidence of aberrant microtubule-kinetochore attachments at metaphase, lagging chromosomes at anaphase, and micronucleation, all of which are indicative of aneuploidy. Cell cycle analysis of p190B deficient MCF-7 cells revealed a significant increase in apoptotic cells with a concomitant decrease in cells in G1 and S phase, suggesting that p190B deficient cells die at the G1 to S transition. Chemical inhibition of the Rac GTPase during mitosis reduced the incidence of lagging chromosomes in p190B knockdown cells to levels detected in control cells, suggesting that aberrant Rac activity in the absence of p190B promotes chromosome segregation defects. Taken together, these data suggest that p190B regulates chromosome segregation and apoptosis in cancer cells. We propose that disruption of mitosis may be one mechanism by which p190B deficiency inhibits tumorigenesis

  16. P190B RhoGAP Regulates Chromosome Segregation in Cancer Cells

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Melissa [Department of Biochemistry and Molecular Biology and the Indiana University Simon Cancer Center, Indiana University School of Medicine, 1234 Notre Dame Avenue, South Bend, IN 46617 (United States); Peddibhotla, Sirisha [Department of Molecular and Human Genetics, Baylor College of Medicine, John P. McGovern Campus, NABS-0250, Houston, TX 77030 (United States); McHenry, Peter [Department of Biology, Southwestern Adventist University, 100 W. Hillcrest, Keene, TX 76059 (United States); Chang, Peggy; Yochum, Zachary; Park, Ko Un; Sears, James Cooper; Vargo-Gogola, Tracy, E-mail: vargo-gogola.1@nd.edu [Department of Biochemistry and Molecular Biology and the Indiana University Simon Cancer Center, Indiana University School of Medicine, 1234 Notre Dame Avenue, South Bend, IN 46617 (United States)

    2012-04-25

    Rho GTPases are overexpressed and hyperactivated in many cancers, including breast cancer. Rho proteins, as well as their regulators and effectors, have been implicated in mitosis, and their altered expression promotes mitotic defects and aneuploidy. Previously, we demonstrated that p190B Rho GTPase activating protein (RhoGAP) deficiency inhibits ErbB2-induced mammary tumor formation in mice. Here we describe a novel role for p190B as a regulator of mitosis. We found that p190B localized to centrosomes during interphase and mitosis, and that it is differentially phosphorylated during mitosis. Knockdown of p190B expression in MCF-7 and Hela cells increased the incidence of aberrant microtubule-kinetochore attachments at metaphase, lagging chromosomes at anaphase, and micronucleation, all of which are indicative of aneuploidy. Cell cycle analysis of p190B deficient MCF-7 cells revealed a significant increase in apoptotic cells with a concomitant decrease in cells in G1 and S phase, suggesting that p190B deficient cells die at the G1 to S transition. Chemical inhibition of the Rac GTPase during mitosis reduced the incidence of lagging chromosomes in p190B knockdown cells to levels detected in control cells, suggesting that aberrant Rac activity in the absence of p190B promotes chromosome segregation defects. Taken together, these data suggest that p190B regulates chromosome segregation and apoptosis in cancer cells. We propose that disruption of mitosis may be one mechanism by which p190B deficiency inhibits tumorigenesis.

  17. Gold-Mining

    DEFF Research Database (Denmark)

    Raaballe, J.; Grundy, B.D.

    2002-01-01

      Based on standard option pricing arguments and assumptions (including no convenience yield and sustainable property rights), we will not observe operating gold mines. We find that asymmetric information on the reserves in the gold mine is a necessary and sufficient condition for the existence...... of operating gold mines. Asymmetric information on the reserves in the mine implies that, at a high enough price of gold, the manager of high type finds the extraction value of the company to be higher than the current market value of the non-operating gold mine. Due to this under valuation the maxim of market...

  18. Improved synthesis of gold and silver nanoshells.

    Science.gov (United States)

    Brito-Silva, Antonio M; Sobral-Filho, Regivaldo G; Barbosa-Silva, Renato; de Araújo, Cid B; Galembeck, André; Brolo, Alexandre G

    2013-04-02

    Metallic nanoshells have been in evidence as multifunctional particles for optical and biomedical applications. Their surface plasmon resonance can be tuned over the electromagnetic spectrum by simply adjusting the shell thickness. Obtaining these particles, however, is a complex and time-consuming process, which involves the preparation and functionalization of silica nanoparticles, synthesis of very small metallic nanoparticles seeds, attachment of these seeds to the silica core, and, finally, growing of the shells in a solution commonly referred as K-gold. Here we present synthetic modifications that allow metallic nanoshells to be obtained in a faster and highly reproducible manner. The main improved steps include a procedure for quick preparation of 2.3 ± 0.5 nm gold particles and a faster approach to synthesize the silica cores. An investigation on the effect of the stirring speed on the shell growth showed that the optimal stirring speeds for gold and silver shells were 190 and 1500 rpm, respectively. In order to demonstrate the performance of the nanoshells fabricated by our method in a typical plasmonic application, a method to immobilize these particles on a glass slide was implemented. The immobilized nanoshells were used as substrates for the surface-enhanced Raman scattering from Nile Blue A.

  19. Thermionics. A bibliography with abstracts. Search period covered: 1970--Apr 1975. [190 references

    Energy Technology Data Exchange (ETDEWEB)

    Grooms, D.W.

    1975-04-01

    Research on thermionic power generation, power plant design, converter design, and basic research on thermionic materials are cited in the bibliography. Spacecraft applications are included. (Contains 190 abstracts).

  20. Half-life measurements in doubly-odd sup(186,188,190)Au nuclei and the 188Hg -> Au decay

    International Nuclear Information System (INIS)

    Abreu, M.C.; Berg, V.; Fransson, K.; Hoeglund, A.; Oms, J.; Porquet, M.G.

    1985-01-01

    A level scheme has been established for 188 Hg -> Au decay which was studied with the online isotope separator ISOCELE. Precise conversion-electron measurements were performed with a semicircular magnetic spectrograph. The half-lives of the 16.0, 82.7 and 114.8 keV levels in 188 Au were measured with a lens electron spectrometer and reduced transition rates were deduced. Similarly the half-lives of the 36.1, 113.9, 227.7, 251.5, 288.0 and 363.6 keV levels in 186 Au and of the 28.9 and 171.5 keV levels in 190 Au were measured. Comparison of the reduced e.m. transition rates shows that a 1 + and a 2 - state have respectively the same structure in sup(186,) sup(188,) sup(190,) 192 Au, the same conclusion holding for the 1 - sub(g.s.) of sup(188,) sup(190,) 192 Au. Additional measurements in 189 , 191 Hg and 185 , 187 Au together with data from the literature enable us to interpret them as a coupling of certain quasiparticle states of neighbouring odd-A nuclei corresponding to oblate shapes. Indications are given that some other negative- and positive-parity states in 188 Au also belong to an oblate system. The nucleus 188 Au appears as the last of a series of doubly-odd gold nuclei where no shape coexistence has, as yet, been observed. (orig.)

  1. 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

  2. Gold mineralogy and extraction

    Energy Technology Data Exchange (ETDEWEB)

    Cashion, J.D.; Brown, L.J. [Monash University, Physics Department (Australia)

    1998-12-15

    Several examples are examined in which Moessbauer spectroscopic analysis of gold mineral samples, treated concentrates and extracted species has provided information not obtainable by competing techniques. Descriptions are given of current work on bacterial oxidation of pyritic ores and on the adsorbed species from gold extracted from cyanide and chloride solutions onto activated carbon and polyurethane foams. The potential benefits for the gold mining industry from Moessbauer studies and some limitations on the use of the technique are also discussed.

  3. Gold mineralogy and extraction

    International Nuclear Information System (INIS)

    Cashion, J.D.; Brown, L.J.

    1998-01-01

    Several examples are examined in which Moessbauer spectroscopic analysis of gold mineral samples, treated concentrates and extracted species has provided information not obtainable by competing techniques. Descriptions are given of current work on bacterial oxidation of pyritic ores and on the adsorbed species from gold extracted from cyanide and chloride solutions onto activated carbon and polyurethane foams. The potential benefits for the gold mining industry from Moessbauer studies and some limitations on the use of the technique are also discussed

  4. 46 CFR 190.15-15 - Ventilation for living spaces and quarters.

    Science.gov (United States)

    2010-10-01

    ... mechanical system unless it can be shown that a natural system will provide adequate ventilation. By a... 46 Shipping 7 2010-10-01 2010-10-01 false Ventilation for living spaces and quarters. 190.15-15... VESSELS CONSTRUCTION AND ARRANGEMENT Ventilation § 190.15-15 Ventilation for living spaces and quarters...

  5. 33 CFR 110.190 - Tortugas Harbor, in vicinity of Garden Key, Dry Tortugas, Fla.

    Science.gov (United States)

    2010-07-01

    ... Garden Key, Dry Tortugas, Fla. 110.190 Section 110.190 Navigation and Navigable Waters COAST GUARD..., in vicinity of Garden Key, Dry Tortugas, Fla. (a) The anchorage grounds. All of Bird Key Harbor, southwest of Garden Key, bounded by the surrounding reefs and shoals and, on the northeast, by a line...

  6. 9 CFR 381.190 - Transactions in slaughtered poultry and other poultry products restricted; vehicle sanitation...

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Transactions in slaughtered poultry and other poultry products restricted; vehicle sanitation requirements. 381.190 Section 381.190... sanitation requirements. (a) No person shall sell, transport, offer for sale or transportation, or receive...

  7. 21 CFR 58.190 - Storage and retrieval of records and data.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Storage and retrieval of records and data. 58.190 Section 58.190 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES..., protocols, specimens, and interim and final reports. Conditions of storage shall minimize deterioration of...

  8. Superdeformation in the A = 190 region. The lead nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Henry, E A; Becker, J A; Brinkman, M J; Kuhnert, A; Stoyer, M A; Wang, T F; Yates, S W [Lawrence Livermore National Lab., CA (United States); Azaiez, F A; Beausang, C W; Burde, J; Deleplanque, M A; Diamond, R M; Draper, J E; Kelly, W H; Korton, W; Macchiavelli, A O; Oliveira, J; Rubel, E; Stephens, F S [Lawrence Berkeley Lab., CA (United States); Cizewski, J A [Rutgers--the State Univ., New Brunswick, NJ (United States)

    1992-08-01

    Superdeformed (SD) bands have been identified in the four even-even lead nuclei {sup 192}Pb, {sup 194}Pb, {sup 196}Pb, and {sup 198}Pb. The discovery of SD bands in these nuclei extended the region of superdeformation in the A = 190 region to Z = 82, and to neutron numbers up to N = 116. All of the SD bands in these nuclei are observed with transition energies ranging from about 250 keV to about 600 keV, with the lowest energy SD band transition for the entire region of 169 keV in {sup 194}Pb. The spins deduced for the lowest levels in the SD bands are 6, 8, and 12 for {sup 192,194,196,198}Pb, respectively. The dynamic moments of inertia of {sup 192}Pb and {sup 194}Pb are similar to each other, and to those of many other SD bands in this mass region. The dynamic moments of inertia of {sup 1}`9{sup 6}Pb and {sup 198}Pb are somewhat lower than those of {sup 192,194}Pb at a given frequency. The experimental lifetimes in {sup 194}Pb and the deduced transition quadrupole moments (Qt {approx} 20 eb) are equal to those of other nuclei in the region within errors. While SD bands have been observed in the odd-neutron Hg and Tl nuclei, SD bands have not been reported for the odd-neutron Pb nuclei. In this contribution we discuss briefly three topics on superdeformation in the lead nuclei. First, we have recent experimental data on {sup 196}Pb that extends our knowledge of the SD band in that nucleus. Next we review briefly the population of low-lying yrast levels from the decay of the SD bands in {sup 192,194,196}Pb. Finally, we summarize our efforts to identify superdeformation in the odd-A Pb nuclei. All of the experiments described here were performed using the HERA spectrometer at the 88-Inch Cyclotron facility located at Lawrence Berkeley Laboratory. (author) 9 refs., 4 figs.

  9. BROOKHAVEN: High energy gold

    International Nuclear Information System (INIS)

    Bleser, Ed

    1992-01-01

    On April 24, Brookhaven's Alternating Gradient Synchrotron (AGS) started to deliver gold ions at 11.4 GeV per nucleon (2,000 GeV per ion) to experimenters who were delighted not only to receive the world's highest energy gold beam but also to receive it on schedule

  10. Gold recovery from low concentrations using nanoporous silica adsorbent

    Science.gov (United States)

    Aledresse, Adil

    gold adsorption shows the high affinity of the mesoporous material to the gold-thiosulphate ([Au (S2O3)2]3- ) ions. A high adsorption saturation level for these materials was found, up to 0.25 mmol (5 mg) Au/g of HMS from gold-thiosulphate solutions. When ammonia was added to the thiosulphate solutions, with or without added copper, the mesoporous material (HMS) achieved the maximum adsorption, 0.24 mmol (47 mg) Au/g of HMS at pH = 7, where as 0.14 mmol (28 mg) Au/g was adsorbed from ammonia-thiosulphate solution at pH > 6. For the fist time, a promising adsorbent system has been found that is capable of effectively concentrating gold thiosulphate complexes, whereas conventional carbon-in-pulp (CIP) and carbon-in-leach (CIL) systems fail. For process design of gold adsorption by HMS particles, certain engineering conditions and practical limitations have to be considered, including particle size of the MP-HMS. Therefore, several experiments have been conducted to enlarge the size of the very fine MP-HMS particles to a size (1--2mm) satisfying the engineering requirements for process design in a real practical and industrial process. The agglomerated mesoporous materials, using sodium metasilicate (Na 2SiO3) binder, adsorbed gold ions in the range of 51%--63% of what the parent HMS powder adsorb. That means the agglomerates can adsorb 19--23% of their own weight (or 190--230 mg Au per one gram of the agglomerated HMS) from [AuCL4]- which is still very satisfactory and acceptable comparing to the current used adsorbents.

  11. Medicinal gold compounds

    International Nuclear Information System (INIS)

    Parish, R.V.; Cottrill, S.M.

    1987-01-01

    A major use of gold compounds in the pharmaceutical industry is for anti-arthritic agents. The disease itself is not understood and little is known about the way in which the drugs act, but detailed pictures of the distribution of gold in the body are available, and some of the relevant biochemistry is beginning to emerge. The purpose of this article is to give a survey of the types of compounds presently employed in medicine, of the distribution of gold in the body which results from their use, and of some relevant chemistry. Emphasis is placed on results obtained in the last few years

  12. The Gold Standard Programme

    DEFF Research Database (Denmark)

    Neumann, Tim; Rasmussen, Mette; Ghith, Nermin

    2013-01-01

    To evaluate the real-life effect of an evidence-based Gold Standard Programme (GSP) for smoking cessation interventions in disadvantaged patients and to identify modifiable factors that consistently produce the highest abstinence rates.......To evaluate the real-life effect of an evidence-based Gold Standard Programme (GSP) for smoking cessation interventions in disadvantaged patients and to identify modifiable factors that consistently produce the highest abstinence rates....

  13. Gold nanoprobes for theranostics

    Science.gov (United States)

    Panchapakesan, Balaji; Book-Newell, Brittany; Sethu, Palaniappan; Rao, Madhusudhana; Irudayaraj, Joseph

    2011-01-01

    Gold nanoprobes have become attractive diagnostic and therapeutic agents in medicine and life sciences research owing to their reproducible synthesis with atomic level precision, unique physical and chemical properties, versatility of their morphologies, flexibility in functionalization, ease of targeting, efficiency in drug delivery and opportunities for multimodal therapy. This review highlights some of the recent advances and the potential for gold nanoprobes in theranostics. PMID:22122586

  14. Facts and Fantasies about Gold

    OpenAIRE

    Klement, Joachim

    2015-01-01

    Due to the increasing popularity of gold as an investment the demand for effective risk management techniques for gold investments has increased as well. In this paper we analyze several drivers of the price of gold that have been proposed in the past. Our analysis indicates that short-term volatility of the price of gold remains rather unpredictable with many of the explanations like the fund flows in physical gold ETF either unreliable or unstable over time. Our analysis suggests that there...

  15. Comparing the Floating Point Systems, Inc. AP-190L to representative scientific computers: some benchmark results

    International Nuclear Information System (INIS)

    Brengle, T.A.; Maron, N.

    1980-01-01

    Results are presented of comparative timing tests made by running a typical FORTRAN physics simulation code on the following machines: DEC PDP-10 with KI processor; DEC PDP-10, KI processor, and FPS AP-190L; CDC 7600; and CRAY-1. Factors such as DMA overhead, code size for the AP-190L, and the relative utilization of floating point functional units for the different machines are discussed. 1 table

  16. Crosstalk between the p190-B RhoGAP and IGF signaling pathways is required for embryonic mammary bud development

    Science.gov (United States)

    P190-B RhoGAP (p190-B, also known as ARHGAP5) has been shown to play an essential role in invasion of the terminal end buds (TEBs) into the surrounding fat pad during mammary gland ductal morphogenesis. Here we report that embryos with a homozygous p190-B gene deletion exhibit major defects in embry...

  17. 41 CFR 102-74.190 - Are portable heaters, fans and other such devices allowed in Government-controlled facilities?

    Science.gov (United States)

    2010-07-01

    ..., fans and other such devices allowed in Government-controlled facilities? 102-74.190 Section 102-74.190... § 102-74.190 Are portable heaters, fans and other such devices allowed in Government-controlled facilities? Federal agencies are prohibited from operating portable heaters, fans, and other such devices in...

  18. 41 CFR 102-33.190 - What are the aircraft operations and ownership costs for which we must account?

    Science.gov (United States)

    2010-07-01

    ... operations and ownership costs for which we must account? 102-33.190 Section 102-33.190 Public Contracts and... Parts Accounting for the Cost of Government Aircraft § 102-33.190 What are the aircraft operations and ownership costs for which we must account? You must account for the operations and ownership costs of your...

  19. Biosynthesis of gold nanoparticles using diatoms-silica-gold and EPS-gold bionanocomposite formation

    OpenAIRE

    Schröfel, Adam; Kratošová, Gabriela; Bohunická, Markéta; Dobročka, Edmund; Vávra, Ivo

    2011-01-01

    Novel synthesis of gold nanoparticles, EPS-gold, and silica-gold bionanocomposites by biologically driven processes employing two diatom strains (Navicula atomus, Diadesmis gallica) is described. Transmission electron microscopy (TEM) and electron diffraction analysis (SAED) revealed a presence of gold nanoparticles in the experimental solutions of the diatom culture mixed with tetrachloroaureate. Nature of the gold nanoparticles was confirmed by X-ray diffraction studies. Scanning electron m...

  20. GOLD IS EARNED FROM THE PRODUCTION OF THAI GOLD LEAF

    Directory of Open Access Journals (Sweden)

    Dirk Bax

    2010-06-01

    Full Text Available Thai people like to cover sacred objects or things dear to them with gold leaf.. Statues of Buddha are sometimes covered with so many layers of gold leaf that they become formless figures, that can hardly be recognized. Portraits of beloved ancestors, statues of elephants and grave tombs are often covered with gold leaf. If one considers the number of Thai people and the popularity of the habit, the amount of gold involved could be considerable.

  1. Gold film with gold nitride - A conductor but harder than gold

    International Nuclear Information System (INIS)

    Siller, L.; Peltekis, N.; Krishnamurthy, S.; Chao, Y.; Bull, S.J.; Hunt, M.R.C.

    2005-01-01

    The formation of surface nitrides on gold films is a particularly attractive proposition, addressing the need to produce harder, but still conductive, gold coatings which reduce wear but avoid the pollution associated with conventional additives. Here we report production of large area gold nitride films on silicon substrates, using reactive ion sputtering and plasma etching, without the need for ultrahigh vacuum. Nanoindentation data show that gold nitride films have a hardness ∼50% greater than that of pure gold. These results are important for large-scale applications of gold nitride in coatings and electronics

  2. Activated carbons and gold

    International Nuclear Information System (INIS)

    McDougall, G.J.; Hancock, R.D.

    1980-01-01

    The literature on activated carbon is reviewed so as to provide a general background with respect to the effect of source material and activation procedure on carbon properties, the structure and chemical nature of the surface of the activated carbon, and the nature of absorption processes on carbon. The various theories on the absorption of gold and silver from cyanide solutions are then reviewed, followed by a discussion of processes for the recovery of gold and silver from cyanide solutions using activated carbon, including a comparison with zinc precipitation

  3. Using the DP-190 glue for adhesive attachment of a large space mirror and its rim

    Science.gov (United States)

    Vlasenko, Oleg; Zverev, Alexey; Sachkov, Mikhail

    2014-07-01

    The glue DP-190 is widely used for adhesive attachment of astrositall (zerodur) lightweight large-size space astronomical mirrors (diameter of 1.7 m and more) with elements of their frames of invar. Peculiarities of physicalmechanical behavior of the glue DP-190 when exposed to the environment during the ground operation and in orbit cause instability of the reflective surface quality of mirrors. In this report we show that even a small (around 1%-5%) volumetric deformation of a cylindrical adhesive layer with a thickness of 0.8 mm between the mirror and the rim element causes significant mirrors deformation. We propose to use adhesive layer of special form that allows to reduce volumetric deformations of the glue DP-190 up to three times. Here we present results based on primary mirror tests of the WSO-UV project.

  4. ['Gold standard', not 'golden standard'

    NARCIS (Netherlands)

    Claassen, J.A.H.R.

    2005-01-01

    In medical literature, both 'gold standard' and 'golden standard' are employed to describe a reference test used for comparison with a novel method. The term 'gold standard' in its current sense in medical research was coined by Rudd in 1979, in reference to the monetary gold standard. In the same

  5. Spectroscopic diagnostic of gold plasma

    International Nuclear Information System (INIS)

    Busquet, M.

    1986-01-01

    Results of a simulation of a gold-aluminium alloy target irradiated by laser are presented. FCI code has been used with a processing out of LTE of atomic physics of gold and of multigroup photonics. Emission and reabsorption of gold and aluminium lines are included [fr

  6. Spectroscopic diagnostic of gold plasma

    Energy Technology Data Exchange (ETDEWEB)

    Busquet, M.

    1986-06-01

    Results of a simulation of a gold-aluminium alloy target irradiated by laser are presented. FCI code has been used with a processing out of LTE of atomic physics of gold and of multigroup photonics. Emission and reabsorption of gold and aluminium lines are included.

  7. Gold Nanoparticle Microwave Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Krantz, Kelsie E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Christian, Jonathan H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Coopersmith, Kaitlin [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Washington, II, Aaron L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Murph, Simona H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-07-27

    At the nanometer scale, numerous compounds display different properties than those found in bulk material that can prove useful in areas such as medicinal chemistry. Gold nanoparticles, for example, display promise in newly developed hyperthermia therapies for cancer treatment. Currently, gold nanoparticle synthesis is performed via the hot injection technique which has large variability in final particle size and a longer reaction time. One underdeveloped area by which these particles could be produced is through microwave synthesis. To initiate heating, microwaves agitate polar molecules creating a vibration that gives off the heat energy needed. Previous studies have used microwaves for gold nanoparticle synthesis; however, polar solvents were used that partially absorbed incident microwaves, leading to partial thermal heating of the sample rather than taking full advantage of the microwave to solely heat the gold nanoparticle precursors in a non-polar solution. Through this project, microwaves were utilized as the sole heat source, and non-polar solvents were used to explore the effects of microwave heating only as pertains to the precursor material. Our findings show that the use of non-polar solvents allows for more rapid heating as compared to polar solvents, and a reduction in reaction time from 10 minutes to 1 minute; this maximizes the efficiency of the reaction, and allows for reproducibility in the size/shape of the fabricated nanoparticles.

  8. Bioassisted Phytomining of Gold

    Science.gov (United States)

    Maluckov, Biljana S.

    2015-05-01

    Bioassisted phytomining implies targeted use of microorganisms and plants for the selective recovery of the metal. Metals from undissolved compounds are dissolved by applying specially chosen microorganisms and therefore become available to the hyperaccumulating plants. In the article, the selective extraction method of base metals and the precious metal gold by using microorganisms and plants is discussed.

  9. Digging for Gold

    Science.gov (United States)

    Waters, John K.

    2012-01-01

    In the case of higher education, the hills are more like mountains of data that "we're accumulating at a ferocious rate," according to Gerry McCartney, CIO of Purdue University (Indiana). "Every higher education institution has this data, but it just sits there like gold in the ground," complains McCartney. Big Data and the new tools people are…

  10. GOLD PRESSURE VESSEL SEAL

    Science.gov (United States)

    Smith, A.E.

    1963-11-26

    An improved seal between the piston and die member of a piston-cylinder type pressure vessel is presented. A layer of gold, of sufficient thickness to provide an interference fit between the piston and die member, is plated on the contacting surface of at least one of the members. (AEC)

  11. Gold Nanoparticle Microwave Synthesis

    International Nuclear Information System (INIS)

    Krantz, Kelsie E.; Christian, Jonathan H.; Coopersmith, Kaitlin; Washington II, Aaron L.; Murph, Simona H.

    2016-01-01

    At the nanometer scale, numerous compounds display different properties than those found in bulk material that can prove useful in areas such as medicinal chemistry. Gold nanoparticles, for example, display promise in newly developed hyperthermia therapies for cancer treatment. Currently, gold nanoparticle synthesis is performed via the hot injection technique which has large variability in final particle size and a longer reaction time. One underdeveloped area by which these particles could be produced is through microwave synthesis. To initiate heating, microwaves agitate polar molecules creating a vibration that gives off the heat energy needed. Previous studies have used microwaves for gold nanoparticle synthesis; however, polar solvents were used that partially absorbed incident microwaves, leading to partial thermal heating of the sample rather than taking full advantage of the microwave to solely heat the gold nanoparticle precursors in a non-polar solution. Through this project, microwaves were utilized as the sole heat source, and non-polar solvents were used to explore the effects of microwave heating only as pertains to the precursor material. Our findings show that the use of non-polar solvents allows for more rapid heating as compared to polar solvents, and a reduction in reaction time from 10 minutes to 1 minute; this maximizes the efficiency of the reaction, and allows for reproducibility in the size/shape of the fabricated nanoparticles.

  12. Quadrupole moments of the 12+ isomers in 188Hg and 190Hg

    International Nuclear Information System (INIS)

    Dracoulis, G.D.; Lonnroth, T.; Vajda, S.; Dafni, E.; Schatz, G.

    1984-01-01

    The electric quadrupole interaction of the 12 + isomers in 188 Hg and 190 Hg has been measured in solid Hg. The quadrupole moments deduced, vertical strokeQ[ 188 Hg(12 + )]vertical stroke = 91(11) e fm 2 and vertical strokeQ[ 190 Hg(12 + )]vertical stroke = 117(14) e fm 2 suggest a possible change in γ-deformation due to the rotation alignment of the isub(13/2) quasi-neutrons. The temperature dependence of the electric field gradient tensor in Hg was also determined. (orig.)

  13. Inter-band coincidences in the superdeformed well of {sup 190}Hg from gammasphere

    Energy Technology Data Exchange (ETDEWEB)

    Crowell, B.; Carpenter, M.P.; Janssens, R.V.F. [and others

    1995-08-01

    Very few experimental observables are ordinarily accessible for superdeformed (SD) states in the A {approximately} 150 and A {approximately} 190 regions. The gamma-decay out of the superdeformed bands usually proceeds directly to the normally deformed states, through highly fragmented pathways, making it difficult to determine the spins, parities and excitation energies of the SD states. The in-band E2 transitions are so collective (2 x 10{sup 3} single-particle units in the A {approximately} 190 region) that it is typically impossible to detect any of the competing M1 and E1 transitions between states in the SD well.

  14. Alpha activity of 190 Pt isotope measured with CR-39 track detector

    International Nuclear Information System (INIS)

    Tavares, O.A.P.; Terranova, M.L.

    1996-11-01

    A new method to measure alpha activity of long-lived radioisotopes is reported. The method consists basically in using CR-39 track detectors in close contact with thick samples of the radioelement to be investigated. Accordingly, a long-term exposure experiment has been performed using metallic sheets of natural platinum to measure alpha activity of platinum 190 isotope. The half-life of platinum 190 has been obtained in good agreement with two recent theoretical half-life predictions. (author). 21 refs., 3 figs., 2 tabs

  15. Gold and gold working in Late Bronze Age Northern Greece

    Science.gov (United States)

    Vavelidis, M.; Andreou, S.

    2008-04-01

    Numerous objects of gold displaying an impressive variety of types and manufacturing techniques are known from the Late Bronze Age (LBA) contexts of Mycenaean Greece, but very little is known about the origin and processing of gold during the second millennium b.c. Ancient literature and recent research indicate that northern Greece is probably the richest gold-bearing region in Greece, and yet, very little evidence exists regarding the exploitation of its deposits and the production as well as use of gold in the area during prehistory. The unusual find of a group of small stone crucibles at the prehistoric settlement of Thessaloniki Toumba, one with visible traces of gold melting, proves local production and offers a rare opportunity to examine the process of on-site gold working. Furthermore, the comparison of the chemical composition of prehistoric artefacts from two settlements with those of gold deposits in their immediate areas supports the local extraction of gold and opens up the prospect for some of the Mycenaean gold to have originated in northern Greece. The scarcity of gold items in northern Greek LBA contexts may not represent the actual amount of gold produced and consumed, but could be a result of the local social attitudes towards the circulation and deposition of artefacts from precious metals.

  16. Moessbauerspectroscopy on Gold Ruby Glass

    International Nuclear Information System (INIS)

    Haslbeck, S.

    2005-01-01

    In this thesis, the chemical states of gold and the physical mechanisms of the growing process of the particles under the influence of additional ingredients like tin, lead, antimony and selenium before, during and after the colouring process are investigated by using the Moessbauer spectroscopy on 197 Au, 119 Sn and 121 Sb, optical spectroscopy and X-ray-diffraction. Gold in an unnealed, colourless state of the glasses consists of monovalent forming linear bonds to two neighbouring oxygen atoms. The Lamb-Moessbauer factor of these gold oxide bondings is observed as 0.095 at 4.2 K. The gold in it's oxide state transforms to gold particles with a diameter of 3 nm to 60 nm. The size of the gold particles is quite definable within the optical spectra and certain sizes are also discernable within the Moessbauer spectra. One component of the Moessbauer spectra is assigned to the surface layer of the gold particles. By comparing this surface component with the amount of the bulk metallic core, one can calculate the size of the gold particles. In the Moessbauer spectra of the colourless glass one also can find parts of bulk metallic gold. Investigations with X-ray diffraction show that these are gold particles with a diameter of 100 nm to 300 nm and therefore have no additional colouring effect within the visible spectrum. The Moessbauer spectra on gold of the remelt glasses are similar to those which have been measured on the initial colourless glasses

  17. Large area nano-patterning /writing on gold substrate using dip - pen nanolithography (DPN)

    Science.gov (United States)

    Saini, Sudhir Kumar; Vishwakarma, Amit; Agarwal, Pankaj B.; Pesala, Bala; Agarwal, Ajay

    2014-10-01

    Dip Pen Nanolithography (DPN) is utilized to pattern large area (50μmX50μm) gold substrate for application in fabricating Nano-gratings. For Nano-writing 16-MHA ink coated AFM tip was prepared using double dipping procedure. Gold substrate is fabricated on thermally grown SiO2 substrate by depositing ˜5 nm titanium layer followed by ˜30nm gold using DC pulse sputtering. The gratings were designed using period of 800nm and 25% duty cycle. Acquired AFM images indicate that as the AFM tip proceeds for nano-writing, line width decreases from 190nm to 100nm. This occurs probably due to depreciation of 16-MHA molecules in AFM tip as writing proceeds.

  18. For the love of gold

    International Nuclear Information System (INIS)

    Young, J.E.

    1993-01-01

    Gold is found in minute quantities and gold mining generates enormous amounts of waste materials and long history of environmental destruction: mercury in tailing, eroded land, and acid mine drainage are legacies of the past. The problem has become worse in recent years in North America, Australia, the Amazon basin, Philippines. This paper describes the economics of gold and the changes in the world economy which has precipitated the new gold rushes. Current technology uses a cyanide solution for leaching small amounts of gold from tons of waste, and mercury remains a toxic waste of gold mining. Both short and long term results of gold mining, on the environment and on indiginous populations are described

  19. High density plasma gun generates plasmas at 190 kilometers per second

    Science.gov (United States)

    Espy, P. N.

    1971-01-01

    Gun has thin metal foil disc which positions or localizes gas to be ionized during electrical discharge cycle, overcoming major limiting factor in obtaining such plasmas. Expanding plasma front travels at 190 km/sec, compared to plasmas of 50 to 60 km/sec previously achieved.

  20. 49 CFR 190.319 - Petitions for extension of time to comment.

    Science.gov (United States)

    2010-10-01

    ... the time for petitioner's comments. A petition is granted only if the petitioner shows good cause for... 49 Transportation 3 2010-10-01 2010-10-01 false Petitions for extension of time to comment. 190... AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE...

  1. 46 CFR 190.07-90 - Vessels contracted for prior to March 1, 1968.

    Science.gov (United States)

    2010-10-01

    ... considered satisfactory so long as they are maintained in good condition to the satisfaction of the Officer in Charge, Marine Inspection. Minor repairs and alterations may be made to the same standards as the... VESSELS CONSTRUCTION AND ARRANGEMENT Structural Fire Protection § 190.07-90 Vessels contracted for prior...

  2. Predicting superdeformed rotational band-head spin in A ∼ 190 ...

    Indian Academy of Sciences (India)

    PACS No. 21.60.−n. 1. Introduction. Superdeformed (SD) nuclei are one of the most challenging and ... like A ∼ 60, 80, 130, 150 and 190 [2,3]. ..... work and the research is progressing to give systematic features of rotational bands of SD.

  3. Evidence for octupole vibration in the superdeformed well of {sup 190}Hg from eurogam

    Energy Technology Data Exchange (ETDEWEB)

    Crowell, B.; Carpenter, M.P.; Janssens, R.V.F. [and others

    1995-08-01

    Gammasphere experiments in 1993-94 brought to light the existence of an excited superdeformed (SD) band in {sup 190}Hg with the unusual property of decaying entirely to the lowest (yrast) SD band over 3-4 transitions, rather than to the normally deformed states as is usually the case in the A {approximately} 150 and A {approximately} 190 regions of superdeformation. Although M1 transitions between signature-partner SD bands were previously observed in {sup 193}Hg, no such mechanism was available to explain the situation in the even-even nucleus {sup 190}Hg, whose yrast SD band has no signature partner. The best explanation appears to lie in long-standing theoretical predictions that the SD minimum in the potential energy surface would be quite soft with respect to octupole vibrations. This would lead to enhanced E1 transitions connecting the one-phonon and zero-phonon states. The data and this interpretation were published. A shortcoming of the Gammasphere experiments was that they did not allow the definitive measurement of the energies of the gamma-ray transitions connecting the two bands, due to the very weak population of the excited band ({approximately}0.05% of the {sup 190}Hg channel) and also partly, we believed, to the angular distributions of the transitions, which were peaked near 90 degrees, where Gammasphere had few detectors.

  4. 40 CFR 725.190 - Notice of commencement of manufacture or import.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Notice of commencement of manufacture... Microbial Commercial Activities Notification Requirements § 725.190 Notice of commencement of manufacture or import. (a) Applicability. Any person who commences the manufacture or import of a new microorganism for...

  5. Rushing for gold

    DEFF Research Database (Denmark)

    Jønsson, Jesper Bosse; Bryceson, Deborah Fahy

    2009-01-01

    African rural dwellers have faced depressed economic prospects for several decades. Now, in a number of mineral-rich countries, multiple discoveries of gold and precious stones have attracted large numbers of prospective small-scale miners. While their 'rush' to, and activities within, mining sit...... affluent than the others, suggesting that movement can be rewarding for those willing to 'try their luck' with the hard work and social networking demands of mining another site.......African rural dwellers have faced depressed economic prospects for several decades. Now, in a number of mineral-rich countries, multiple discoveries of gold and precious stones have attracted large numbers of prospective small-scale miners. While their 'rush' to, and activities within, mining sites...

  6. Gold' 82 - technical sessions

    International Nuclear Information System (INIS)

    Viewing, K.

    1983-01-01

    Sulphur-isotope studies had been applied by Dr. I. Lambert to a number of deposits in Western Australia and also to certain samples from Vubachickwe and other deposits in Zimbabwe. A study of the sulphur isotopes at the Dickenson Mine, revealed a wide spread of values in the mineralised zones. Metamorphic processes were likely to be significant in the concentration of gold. The iron formations at the Old Jardine Mine had been unfolded by Dr. W.S. Hallager and the pattern of sedimentation was unraveled. A gold-rich zone was separated by a barren gap from the other part of the mineralised zone. Research was also done on the effects of the metamorphic processes, and the ages of mineralisation

  7. Spitzer Observations of a 24 μm Shadow: Bok Globule CB 190

    Science.gov (United States)

    Stutz, Amelia M.; Bieging, John H.; Rieke, George H.; Shirley, Yancy L.; Balog, Zoltan; Gordon, Karl D.; Green, Elizabeth M.; Keene, Jocelyn; Kelly, Brandon C.; Rubin, Mark; Werner, Michael W.

    2007-08-01

    We present Spitzer observations of the dark globule CB 190 (LDN 771). We observe a roughly circular 24 μm shadow with a 70" radius. The extinction profile of this shadow matches the profile derived from 2MASS photometry at the outer edges of the globule and reaches a maximum of ~32 visual magnitudes at the center. The corresponding mass of CB 190 is ~10 Msolar. Our 12CO and 13CO J=2-1 data over a 10'×10' region centered on the shadow show a temperature ~10 K. The thermal continuum indicates a similar temperature for the dust. The molecular data also show evidence of freezeout onto dust grains. We estimate a distance to CB 190 of 400 pc using the spectroscopic parallax of a star associated with the globule. Bonnor-Ebert fits to the density profile, in conjunction with this distance, yield ξmax=7.2, indicating that CB 190 may be unstable. The high temperature (56 K) of the best-fit Bonnor-Ebert model is in contradiction with the CO and thermal continuum data, leading to the conclusion that the thermal pressure is not enough to prevent free-fall collapse. We also find that the turbulence in the cloud is inadequate to support it. However, the cloud may be supported by the magnetic field, if this field is at the average level for dark globules. Since the magnetic field will eventually leak out through ambipolar diffusion, it is likely that CB 190 is collapsing or in a late precollapse stage. This work is based in part on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under NASA contract 1407.

  8. Radioactive gold ring dermatitis

    International Nuclear Information System (INIS)

    Miller, R.A.; Aldrich, J.E.

    1990-01-01

    A superficial squamous cell carcinoma developed in a woman who wore a radioactive gold ring for more than 30 years. Only part of the ring was radioactive. Radiation dose measurements indicated that the dose to basal skin layer was 2.4 Gy (240 rad) per week. If it is assumed that the woman continually wore her wedding ring for 37 years since purchase, she would have received a maximum dose of approximately 4600 Gy

  9. Immunological properties of gold nanoparticles.

    Science.gov (United States)

    Dykman, Lev A; Khlebtsov, Nikolai G

    2017-03-01

    In the past decade, gold nanoparticles have attracted strong interest from the nanobiotechnological community owing to the significant progress made in robust and easy-to-make synthesis technologies, in surface functionalization, and in promising biomedical applications. These include bioimaging, gene diagnostics, analytical sensing, photothermal treatment of tumors, and targeted delivery of various biomolecular and chemical cargos. For the last-named application, gold nanoparticles should be properly fabricated to deliver the cargo into the targeted cells through effective endocytosis. In this review, we discuss recent progress in understanding the selective penetration of gold nanoparticles into immune cells. The interaction of gold nanoparticles with immune cell receptors is discussed. As distinct from other published reviews, we present a summary of the immunological properties of gold nanoparticles. This review also summarizes what is known about the application of gold nanoparticles as an antigen carrier and adjuvant in immunization for the preparation of antibodies in vivo . For each of the above topics, the basic principles, recent advances, and current challenges are discussed. Thus, this review presents a detailed analysis of data on interaction of gold nanoparticles with immune cells. Emphasis is placed on the systematization of data over production of antibodies by using gold nanoparticles and adjuvant properties of gold nanoparticles. Specifically, we start our discussion with current data on interaction of various gold nanoparticles with immune cells. The next section describes existing technologies to improve production of antibodies in vivo by using gold nanoparticles conjugated with specific ligands. Finally, we describe what is known about adjuvant properties of bare gold or functionalized nanoparticles. In the Conclusion section, we present a short summary of reported data and some challenges and perspectives.

  10. 27 CFR 19.742 - Tank record of wine or spirits of less than 190 degrees of proof.

    Science.gov (United States)

    2010-04-01

    ... Records and Reports Storage Account § 19.742 Tank record of wine or spirits of less than 190 degrees of... wine or spirits of less than 190 degrees of proof to show deposits into, withdrawals from, and the...; (3) Identification of the tank; (4) Kind of wine or spirits; (5) Number and average proof gallon...

  11. The extractive metallurgy of gold

    Energy Technology Data Exchange (ETDEWEB)

    Kongolo, K.; Mwema, M.D. [University of Lubumbashi, Zaire, Gecamines Metallurgical Research Centre, Likasi, Zaire, c/o Gecamines Brussels (Belgium)

    1998-12-15

    Moessbauer spectroscopy has been successfully used in investigation of the gold compounds present in ores and the gold species which occur during the process metallurgy of this metal. This paper is a survey of the basic recovery methods and techniques used in extractive metallurgy of gold. Process fundamentals on mineral processing, ore leaching, zinc dust cementation, adsorption on activated carbon, electrowinning and refining are examined. The recovery of gold as a by-product of the copper industry is also described. Alternative processing methods are indicated in order to shed light on new interesting research topics where Moessbauer spectroscopy could be applied.

  12. The extractive metallurgy of gold

    Science.gov (United States)

    Kongolo, K.; Mwema, M. D.

    1998-12-01

    Mössbauer spectroscopy has been successfully used in investigation of the gold compounds present in ores and the gold species which occur during the process metallurgy of this metal. This paper is a survey of the basic recovery methods and techniques used in extractive metallurgy of gold. Process fundamentals on mineral processing, ore leaching, zinc dust cementation, adsorption on activated carbon, electrowinning and refining are examined. The recovery of gold as a by-product of the copper industry is also described. Alternative processing methods are indicated in order to shed light on new interesting research topics where Mössbauer spectroscopy could be applied.

  13. The extractive metallurgy of gold

    International Nuclear Information System (INIS)

    Kongolo, K.; Mwema, M.D.

    1998-01-01

    Moessbauer spectroscopy has been successfully used in investigation of the gold compounds present in ores and the gold species which occur during the process metallurgy of this metal. This paper is a survey of the basic recovery methods and techniques used in extractive metallurgy of gold. Process fundamentals on mineral processing, ore leaching, zinc dust cementation, adsorption on activated carbon, electrowinning and refining are examined. The recovery of gold as a by-product of the copper industry is also described. Alternative processing methods are indicated in order to shed light on new interesting research topics where Moessbauer spectroscopy could be applied

  14. Surface-stabilized gold nanocatalysts

    Science.gov (United States)

    Dai, Sheng [Knoxville, TN; Yan, Wenfu [Oak Ridge, TN

    2009-12-08

    A surface-stabilized gold nanocatalyst includes a solid support having stabilizing surfaces for supporting gold nanoparticles, and a plurality of gold nanoparticles having an average particle size of less than 8 nm disposed on the stabilizing surfaces. The surface-stabilized gold nanocatalyst provides enhanced stability, such as at high temperature under oxygen containing environments. In one embodiment, the solid support is a multi-layer support comprising at least a first layer having a second layer providing the stabilizing surfaces disposed thereon, the first and second layer being chemically distinct.

  15. Compliance determination procedures for environmental radiation protection standards for uranium recovery facilities 40 CFR part 190

    International Nuclear Information System (INIS)

    1982-03-01

    Uranium Milling operations are licensed by the Nuclear Regulatory Commission and by some States in agreement with the Commission. The radiation dose to any individual from the operation of facilities within the uranium fuel cycle is limited to levels set by the Environmental Protection Agency. These levels are contained in the EPA Environmental Radiation Protection Standards for Nuclear Power Operations, in Part 190 of Title 40 of the Code of Federal Regulations (40 CFR Part 190). This report describes the procedures used within NRC's Uranium Recovery Licensing Branch for evaluating compliance with these regulations for uranium milling operations. The report contains descriptions of these procedures, dose factors for evaluating environmental measurement data, and guidance to the NRC staff reviewer

  16. Microscopic structure of high-spin vibrational states in superdeformed A=190 nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Nakatsukasa, Takashi [Chalk River Labs., Ontario (Canada); Matsuyanagi, Kenichi [Kyoto Univ. (Japan); Mizutori, Shoujirou [Oak Ridge National Lab., TN (United States)] [and others

    1996-12-31

    Microscopic RPA calculations based on the cranked shell model are performed to investigate the quadrupole and octupole correlations for excited superdeformed (SD) bands in even-even A=190 nuclei. The K = 2 octupole vibrations are predicted to be the lowest excitation modes at zero rotational frequency. The Coriolis coupling at finite frequency produces different effects depending on the neutron and proton number of nucleus. The calculations also indicate that some collective excitations may produce moments of inertia almost identical to those of the yrast SD band. An interpretation of the observed excited bands invoking the octupole vibrations is proposed, which suggests those octupole vibrations may be prevalent in even-even SD A=190 nuclei.

  17. 31 CFR 100.4 - Gold coin and gold certificates in general.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Gold coin and gold certificates in... EXCHANGE OF PAPER CURRENCY AND COIN In General § 100.4 Gold coin and gold certificates in general. Gold coins, and gold certificates of the type issued before January 30, 1934, are exchangeable, as provided...

  18. Determining gold content

    International Nuclear Information System (INIS)

    Clayton, C.G.; Wormald, M.R.

    1981-01-01

    A method for determining the gold content of a material, comprises irradiating a body of the material with neutrons and determining the intensity of γ-rays having an energy of 279 keV arising from the reaction 179 Au(nn') 179 Au → 279 keV. The apparatus has means for conveying the materials past an assembly, which has a neutron source, which does not produce neutrons having sufficient energy to excite fast neutron reactions in non-auriferous constituents. (author)

  19. Turning lead into gold

    DEFF Research Database (Denmark)

    Jensen, Steffen Moltrup Ernø

    For years the field of entrepreneurship has been blinded by the alchemical promise of turning lead into gold, of finding the ones most likely to become the next Branson, Zuckerberg or Gates. The promise has been created in the midst of political and scientific agendas where certain individuals...... is not to accumulate state or market wealth, but for entrepreneurial skills to become tools towards the liberation of the individual from oppressive systems of control – essentially to add public value rather than economic value. In this presentation I will sketch an anarchist perspective on entrepreneurship, looking...

  20. Three-dimensional structure and stoichiometry of Helmintosporium victoriae190S totivirus

    International Nuclear Information System (INIS)

    Caston, Jose R.; Luque, Daniel; Trus, Benes L.; Rivas, German; Alfonso, Carlos; Gonzalez, Jose M.; Carrascosa, Jose L.; Annamalai, Padmanaban; Ghabrial, Said A.

    2006-01-01

    Most double-stranded RNA viruses have a characteristic capsid consisting of 60 asymmetric coat protein dimers in a so-called T = 2 organization, a feature probably related to their unique life cycle. These capsids organize the replicative complex(es) that is actively involved in genome transcription and replication. Available structural data indicate that their RNA-dependent RNA polymerase (RDRP) is packaged as an integral capsid component, either as a replicative complex at the pentameric vertex (as in reovirus capsids) or as a fusion protein with the coat protein (as in some totivirus). In contrast with members of the family Reoviridae, there are two well-established capsid arrangements for dsRNA fungal viruses, exemplified by the totiviruses L-A and UmV and the chrysovirus PcV. Whereas L-A and UmV have a canonical T = 2 capsid, the PcV capsid is based on a T = 1 lattice composed of 60 capsid proteins. We used cryo-electron microscopy combined with three-dimensional reconstruction techniques and hydrodynamic analysis to determine the structure at 13.8 A resolution of Helminthosporium victoriae 190S virus (Hv190SV), a totivirus isolated from a filamentous fungus. The Hv190SV capsid has a smooth surface and is based on a T = 2 lattice with 60 equivalent dimers. Unlike the RDRP of some other totiviruses, which are expressed as a capsid protein-RDRP fusion protein, the Hv190SV RDRP is incorporated into the capsid as a separate, nonfused protein, free or non-covalently associated to the capsid interior

  1. Determination of Gold from Gold Matrix of North Western Nigeria ...

    African Journals Online (AJOL)

    The research paper presents analytical results of Au, Mn and V concentrations of some Nigerian gold ores using two techniques: epithermal neutron activation analysis (ENAA) and proton induced X-ray emission (PIXE). Fourteen samples were collected from gold fields of North Western Nigeria, prepared separately to a ...

  2. Utilities for developing HITAC 10-2 program with U-400 and M-190 systems

    International Nuclear Information System (INIS)

    Tsuda, Kenzo.

    1979-06-01

    At the time of developing ''On-line experimental data processing system for JIPP (Japan Institute of Plasma Physics) T-2'', a number of utilities have been developed, which can develop the programs on the HITAC 10-2 side through the PANAFACOM U-400 and the FACOM M-190 computer systems. The HITAC 10-2 is a computer mainly composed of core memories, whose performances of processing speed, peripherals and softwares are considerably different from large and medium size computers. For this reason, it requires tremendous time and labor to develop large scale programs or systems by utilizing only the HITAC 10-2. Accordingly, some utilities have been developed with the U-400 and M-190 systems in order to shorten the developing time and improve the developing efficiency. In the example of above ''On-line experimental data processing system for JIPP T-2'', the time required for one debugging can be reduced to 20 minutes from former 5 to 6 hours. In this report, first, the program development by the HITAC 10-2, and next, the bind processing with U-400 and the cross-assembling with M-190 are described. Then the functions and the method for use of the utilities are explained. (Wakatsuki, Y.)

  3. Activation analysis in gold industry

    International Nuclear Information System (INIS)

    Kist, A. A.

    2003-01-01

    Nuclear techniques and methods were, are, and will be very important for many fields of science, agriculture, industry, etc. Among other examples one can remember role of the nuclear medicine (radiotherapy and radiodiagnostic methods) or semiconductors (communication, computing, information, etc.) which industrial production has been on initial stage based on activation analysis. One of very illustrative examples is application of nuclear methods in gold industry. This is given by favorable nuclear properties of gold. Uzbekistan is one of the main producers of gold. Open-cast mining and hydro metallurgic extraction (using leaching by cyanide and sorption by ion-exchange resin) is the mostly used technology. The typical gold ores are sulfide and contain elevated concentration of As and Sb. That needs special technology of gold extraction. Importance of gold for Uzbekistan economy is a reason why for many years there are carried out studies concerning to gold production. These studies include also nuclear methods and their results are successfully used in gold industry. The present paper gives a brief overview for period of 25 years. For many reasons most of these studies were not published before completely. Despite some results are obtained decades ago we decided to present the overview as an example how nuclear methods can cover requirements of the whole process. We are trying to sort these studies according to methods and applications

  4. Stealing the Gold

    International Nuclear Information System (INIS)

    Whittington, S G

    2005-01-01

    Stealing the Gold presents a survey of some of the most exciting topics in condensed matter physics today, from the perspective of the pioneering work of Sam Edwards. Original articles from leaders in the field, including several Nobel laureates, highlight the historical development as well as new and emerging areas. This book would be of interest to graduate students and researchers in condensed matter physics, statistical physics and theoretical physics. Over the course of nearly half a century, Sam Edwards has led the field of condensed matter physics in new directions, ranging from the electronic and statistical properties of disordered materials to the mechanical properties of granular materials. Along the way he has provided seminal contributions to fluid mechanics, polymer science, surface science and statistical mechanics. This volume celebrates the immense scope of his influence by presenting a collection of original articles by recognized leaders in theoretical physics, including two Nobel laureates and a Fields medalist, which describe the genesis, evolution and future prospects of the various sub-fields of condensed matter theory, along with reprints of a selection of Edwards' seminal papers that helped give birth to the subject. Stealing the Gold, Edwards' favourite caricature of the relationship between theoretical physicists and nature, will be of singular interest to graduate students looking for an overview of some of the most exciting areas of theoretical physics, as well as to researchers in condensed matter physics looking for a comprehensive, broad and uniquely incisive snapshot of their subject at the dawn of the 21st century. (book review)

  5. Cosmogenic 3He in detrital gold

    Science.gov (United States)

    Stuart, Finlay; Yakubovich, Olga; Caracedo, Ana; Nesterenok, Alexander

    2017-04-01

    Since the measurement of cosmogenic He in an alluvial diamond by McConville and Reynolds (1996) the application of cosmogenic noble gases to individual detrital grains to quantify surface processes has not been vigorously pursued. The likely low rate of diffusion of cosmogenic He in native metals, and their resistance to weathering and disintegration during erosion and transport, makes them a potential record of long-term Earth surface processes. In an effort to assess the extent that detrital refractory metals record the exposure history during transport and storage we have undertaken a reconnaissance study of the He isotope composition in 18 grains (2-200 mg) of native gold, copper, silver, and PtPd, Pt3Fe and OsIr alloys from alluvial placer deposits from around the world. 4He is dominantly the result of U and Th decay within the grains, or decay of 190Pt in the Pt-rich alloys. 3He is measurable in 13 grains, concentrations range up to 2.7E+6 atoms/g. 3He/4He are always in excess of the crustal radiogenic ratio, up to 306 Ra. Although nucleogenic 3He produced by (n,α) reactions on 6Li, and 3He from trapped hydrothermal fluids, are present, the majority of the 3He is cosmogenic in origin. Using newly calculated cosmogenic 3He production rates in heavy metals, and a determination of the effect of implantation based on the stopping distances of spallogenic 3He and 3H, the grains have 3Hecos concentrations that are equivalent to 0.35 to 1.5 Ma exposure at Earth's surface. In a study of detrital gold grains from several sites in Scotland we have found that 10 % have 3He concentrations that are significantly in excess of that generated since the Last Glacial Maximum. These studies demonstrate that, with refinement, cosmogenic 3He in refractory detrital minerals can be used to quantify sediment transport and storage on the 1-10 Ma timescale. P. McConville & J.H. Reynolds (1989). Geochim. Cosmochim. Acta, 53, 2365-75.

  6. Shape transition in Pt-nuclei with mass A ∼190

    International Nuclear Information System (INIS)

    Chamoli, S.K.

    2017-01-01

    The nuclei in mass region A ∼190 are well known for the prolate-oblate shape co-existence/transition phenomena. The shape coexistence phenomena has been observed in nuclei like Hg and Tl of this mass region. The calculations done for Pt nuclei in indicate a smooth shape change from prolate deformed "1"8"6Pt to nearly spherical "2"0"2"-"2"0"4 Pt through the region of triaxially deformed "1"8"8"-"1"9"8Pt and slightly oblate "2"0"0Pt. In these calculations, a change of shape from prolate to oblate is expected at A = 188. In recent high spin spectroscopic investigations, significant amount of reduced prolate collectivity has been observed in "1"8"8Pt. The level lifetimes provide valuable information about the nuclear shape and also the shape change with increase in spin along a band. So, to get clear signature of prolate to oblate shape inversion in Pt nuclei near A = 190, it is required to perform lifetime measurements. With this objective, the RDM lifetime measurements of high spin states have been done for various even-even Pt isotopes with masss A ≤ 186 over the years. The results obtained in these measurements are very encouraging and do indicate changing nuclear structure for Pt-isotopes with increasing mass at low spins. A gradual increase in B(E2) values upto 4"+ state and near constant nature there after in "1"8"8Pt, contrary to the other light neighboring Pt nuclei tends to indicate the volatile nature of deformation in Pt nuclei near A ∼ 190 which needs further theoretical investigations. (author)

  7. A Study of the 190 keV Transition in {sup 141}La

    Energy Technology Data Exchange (ETDEWEB)

    Berg, V; Hoeglund, Aa [Inst. of Physics, Univ. of Stockholm (Sweden); [AB Atome nergi, Nykoping (Sweden); Fogelberg, B [Inst. of Physics, Uppsala Univ. (Sweden)

    1970-05-15

    The gamma-ray spectrum from the decay of 18 min 141 Ba has been studied. Seventeen transitions were found below 900 keV, with energies and (intensities) as follows: 112.9{+-}0.2(3.0), 163.1{+-}0.3 (1.0), 165.7{+-}0.4(0.7), 180.5{+-}0.2(0.9), 190.3{+-}0.1(100), 276.9{+-}0.1 (52.2), 304.2{+-}0.1(55.8), 343.6{+-}0.1(30.8), 364.4{+-}0.6(1.6), 389.7{+-}0.2(2.8), 457.7{+-}0.2(10.4), 462.3{+-}0.2(10.5), 467.3{+-}0.1(11.4), 625.1{+-}0.2(6.1), 647.9{+-}0.2(10.7), 739.1{+-}0.3(8.7), 876.5{+-}0.3(6.7). K- and L-shell conversion coefficients have been measured for the 190. 3 keV transition, yielding a multipolarity of M1 + < 8 % E2. Half-life measurements using delayed coincidence technique have given the following results: T{sub 1/2} (190 keV level) = 1.27 {sup +0.06}{sub -0.10} ns, T{sub 1/2} (304 keV level) < 200 ps, T{sub 1/2} (467 keV level) < 120 ps. A level scheme of {sup 141}La has been constructed, and the spin-parity assignments of the ground state and first excited state are discussed in terms of the shell model.

  8. Investigations of fast neutron production by 190 GeV/c muon interactions on graphite target

    CERN Document Server

    Chazal, V; Cook, B; Henrikson, H; Jonkmans, G; Paic, A; Mascarenhas, N; Vogel, P; Vuilleumier, J L

    2002-01-01

    The production of fast neutrons (1 MeV - 1 GeV) in high energy muon-nucleus interactions is poorly understood, yet it is fundamental to the understanding of the background in many underground experiments. The aim of the present experiment (CERN NA55) was to measure spallation neutrons produced by 190 GeV/c muons scattering on carbon target. We have investigated the energy spectrum and angular distribution of spallation neutrons, and we report the result of our measurement of the neutron production differential cross section.

  9. Investigations of fast neutron production by 190 GeV/c muon interactions on different targets

    International Nuclear Information System (INIS)

    Chazal, V.; Boehm, F.; Cook, B.; Henrikson, H.; Jonkmans, G.; Paic, A.; Mascarenhas, N.; Vogel, P.; Vuilleumier, J.-L.

    2002-01-01

    The production of fast neutrons (1 MeV-1 GeV) in high-energy muon-nucleus interactions is poorly understood, yet it is fundamental to the understanding of the background in many underground experiments. The aim of the present experiment (CERN NA55) was to measure spallation neutrons produced by 190 GeV/c muons scattering on carbon, copper and lead targets. We have investigated the energy spectrum and angular distribution of spallation neutrons, and we report the result of our measurement of the neutron production differential cross-section

  10. AP190L and PDP-KI10: a hardware/software measurement report

    International Nuclear Information System (INIS)

    Maron, N.; Sutherland, G.G.

    1979-01-01

    This report discusses an AP190L array processor (manufactured by Floating Point Systems of Beaverton, Oregon) interfaced to a PDP-10 (Digital Equipment Corporation, Maynard, Mass.). After AP software installation, an analysis of the overhead was performed. The results of these measurements and some conclusions are presented. An AP monitor and software interface were written to minimize the overhead from the PDP-10. A vector extension to the FORTRAN language called FIVE was developed to increase user access to the AP. Some of the problems associated with defining and implementing FIVE are discussed. Its successes and limitations are reviewed. 2 figures, 2 tables

  11. Staggering in signature partners of A∼190 mass region of superdeformed rotational bands

    International Nuclear Information System (INIS)

    Uma, V.S.; Goel, Alpana; Yadav, Archana

    2014-01-01

    This paper discuss about ΔI=1 signature splitting in signature partner pairs of A∼190 mass region. Around twenty signature partner pairs (usually called as two bands, each with a fixed signature) have been reported in this mass region. For these signature pairs, band head moment of inertia (J 0 ) and intrinsic structure of each pair of signature partners have been found as almost identical. Also, these signature partner pairs showed large amplitude signature splitting. As each of the two signature partner forms a regular spin sequence and signature bands are not equivalent in terms of energies. This difference in energies results in signature splitting

  12. Gamma-ray deexcitation of 0/sup +/, 2/sup +/ states in /sup 188/ /sup 190/Os

    Energy Technology Data Exchange (ETDEWEB)

    Macphail, M R; Casten, R F; Kane, W R [Brookhaven National Lab., Upton, N.Y. (USA)

    1975-12-08

    The ..gamma..-ray deexcitation of eight 0/sup +/ states in /sup 188/ /sup 190/Os was studied with the (n,..gamma..) reaction. For all eight 0/sup +/ states the depopulation was primarily to the 2/sup +//sub ..gamma../ rather than to the 2/sup +//sub g/ level. The 2/sup +/ level above the lowest excited 0/sup +/ state in each nucleus was found to decay predominantly to the excited 0/sup +/ level. Comparisons of these results to the longitudinal correspondence model and to the calculations of Kumar and Barranger are made.

  13. Higher superdeformed band members in {sup 190}Hg. Evidence for a band interaction

    Energy Technology Data Exchange (ETDEWEB)

    Bearden, I G; Daly, P J [Purdue Univ., Lafayette, IN (United States); Janssens, V F; Carpenter, M P; Ahmad, I; Khoo, T L; Lauritsen, T; Liang, Y [Argonne National Lab., IL (United States); Drigert, M W [Idaho National Engineering Lab., Idaho Falls, ID (United States); Garg, U; Reviol, W [Notre Dame Univ., IN (United States); Wyss, R [Joint Inst. for Heavy Ion Research, Oak Ridge, TN (United States)

    1992-08-01

    The superdeformed band of {sup 190}Hg has been traced up to a frequency {Dirac_h}{omega} {>=} 0.4 MeV by combining data from several experiments. A distinct change in the slope of the dynamic moment of inertia J{sup (2)} vs {Dirac_h}{omega} is observed at {Dirac_h}{omega} 0.32 MeV. This result is interpreted as evidence for a band interaction at the highest frequencies. Possible interpretations are reviewed. (author) 14 refs., 3 figs.

  14. Lifetime measurements and dipole transition rates for superdeformed states in {sup 190}Hg.

    Energy Technology Data Exchange (ETDEWEB)

    Amro, H.

    1999-03-24

    The Doppler-shift attenuation method was used to measure life-times of superdeformed (SD) states for both the yrast and the first excited superdeformed band of {sup 190}Hg. Intrinsic quadruple moments Q{sub 0} were extracted. For the first time, the dipole transition rates have been extracted for the inter-band transitions which connect the excited SD band to the yrast states in the second minimum. The results support the interpretation of the excited SD band as a rotational band built on an octupole vibration.

  15. Lifetime measurements and dipole transition rates for superdeformed states in 190Hg

    International Nuclear Information System (INIS)

    Amro, H.

    1999-01-01

    The Doppler-shift attenuation method was used to measure life-times of superdeformed (SD) states for both the yrast and the first excited superdeformed band of 190 Hg. Intrinsic quadruple moments Q 0 were extracted. For the first time, the dipole transition rates have been extracted for the inter-band transitions which connect the excited SD band to the yrast states in the second minimum. The results support the interpretation of the excited SD band as a rotational band built on an octupole vibration

  16. 190-C Facility <90 Day Storage Pad supplemental information to the Hanford facility contingency plan

    International Nuclear Information System (INIS)

    Little, N.C.

    1996-12-01

    The 190-C Facility <90 Day Storage Pad stores waste oils primarily contaminated with lead generated while draining equipment within the building of residual lubricating oils. Waste oils are packaged and stored in fifty-five gallon drums, or other containers permitted by the Site Specific Waste Management Instruction. Bechtel Hanford, Inc. (BHI) manual BHI-EE-02, Environmental Requirements Procedures, references this document. This document is to be used to demonstrate compliance with the contingency plan requirements in Washington Administrative Code, Chapter 173-303, Dangerous Waste Regulations, for certain Resource Conservation and Recovery Act of 1976 (RCRA) waste management units (units). Refer to BHI-EE-02, for additional information

  17. Directed Assembly of Gold Nanoparticles

    DEFF Research Database (Denmark)

    Westerlund, Axel Rune Fredrik; Bjørnholm, Thomas

    2009-01-01

    As a complement to common "top-down" lithography techniques, "bottom-up" assembly techniques are emerging as promising tools to build nanoscale structures in a predictable way. Gold nanoparticles that are stable and relatively easy to synthesize are important building blocks in many such structures...... due to their useful optical and electronic properties. Programmed assembly of gold nanoparticles in one, two, and three dimensions is therefore of large interest. This review focuses on the progress from the last three years in the field of directed gold nanoparticle and nanorod assembly using...

  18. GOLD and the fixed ratio

    Directory of Open Access Journals (Sweden)

    Vestbo J

    2012-09-01

    Full Text Available Jørgen VestboUniversity of Manchester, Manchester, UKI read with interest the paper entitled "Diagnosis of airway obstruction in the elderly: contribution of the SARA study" by Sorino et al in a recent issue of this journal.1 Being involved in the Global Initiative for Obstructive Lung Diseases (GOLD, it is nice to see the interest sparked by the GOLD strategy document. However, in the paper by Sorino et al, there are a few misunderstandings around GOLD and the fixed ratio (forced expiratory volume in 1 second/forced volume vital capacity < 0.70 that need clarification.View original paper by Sorino and colleagues.

  19. New evaluation of alpha decay half-life of 190Pt isotope for the Pt-Os dating system

    International Nuclear Information System (INIS)

    Tavares, O.A.P.; Medeiros, E.L.; Terranova, M.L.

    2005-08-01

    A semiempirical model based on the quantum mechanical tunnelling mechanism of alpha emission from nuclei has been used to evaluate the half-life of the Pt isotopes. For the important naturally occurring 190 Pt isotope, the radiogenic parent in the 190 Pt → 186 Os dating system, the model yielded a half-life value of (3.7± 0.3) versus 10 11 y. This is comparable to (3.2±0.1) versus 10 11 y which was obtained in the last direct counting experiment to measure the alpha activity of 190 Pt (Tavares and Terranova, Rad. Measurem. 27 (1997) 19). A literature survey of available alpha decay half-life values for 190 Pt isotope is also reported. The significant discrepancies found between data obtained by direct counting, indirect geological methods and different calculation models are analysed and discussed. (author)

  20. Enhancement of gold recovery using bioleaching from gold concentrate

    Science.gov (United States)

    Choi, S. H.; Cho, K. H.; Kim, B. J.; Choi, N. C.; Park, C. Y.

    2012-04-01

    The gold in refractory ores is encapsulated as fine particles (sometimes at a molecular level) in the crystal structure of the sulfide (typically pyrite with or without arsenopyrite) matrix. This makes it impossible to extract a significant amount of refractory gold by cyanidation since the cyanide solution cannot penetrate the pyrite/arsenopyrite crystals and dissolve gold particles, even after fine grinding. To effectively extract gold from these ores, an oxidative pretreatment is necessary to break down the sulfide matrix. The most popular methods of pretreatment include nitric acid oxidation, roasting, pressure oxidation and biological oxidation by microorganisms. This study investigated the bioleaching efficiency of Au concentrate under batch experimental conditions (adaptation cycles and chemical composition adaptation) using the indigenous acidophilic bacteria collected from gold mine leachate in Sunsin gold mine, Korea. We conducted the batch experiments at two different chemical composition (CuSO4 and ZnSO4), two different adaptation cycles 1'st (3 weeks) and 2'nd (6 weeks). The results showed that the pH in the bacteria inoculating sample decreased than initial condition and Eh increased. In the chemical composition adaptation case, the leached accumulation content of Fe and Pb was exhibited in CuSO4 adaptation bacteria sample more than in ZnSO4 adaptation bacteria samples, possibly due to pre-adaptation effect on chalcopyrite (CuFeS2) in gold concentrate. And after 21 days on the CuSO4 adaptation cycles case, content of Fe and Pb was appeared at 1'st adaptation bacteria sample(Fe - 1.82 and Pb - 25.81 times per control sample) lower than at 2'nd adaptation bacteria sample(Fe - 2.87 and Pb - 62.05 times per control sample). This study indicates that adaptation chemical composition and adaptation cycles can play an important role in bioleaching of gold concentrate in eco-/economic metallurgy process.

  1. Sensitivity of immune response quality to influenza helix 190 antigen structure displayed on a modular virus-like particle.

    Science.gov (United States)

    Anggraeni, Melisa R; Connors, Natalie K; Wu, Yang; Chuan, Yap P; Lua, Linda H L; Middelberg, Anton P J

    2013-09-13

    Biomolecular engineering enables synthesis of improved proteins through synergistic fusion of modules from unrelated biomolecules. Modularization of peptide antigen from an unrelated pathogen for presentation on a modular virus-like particle (VLP) represents a new and promising approach to synthesize safe and efficacious vaccines. Addressing a key knowledge gap in modular VLP engineering, this study investigates the underlying fundamentals affecting the ability of induced antibodies to recognize the native pathogen. Specifically, this quality of immune response is correlated to the peptide antigen module structure. We modularized a helical peptide antigen element, helix 190 (H190) from the influenza hemagglutinin (HA) receptor binding region, for presentation on murine polyomavirus VLP, using two strategies aimed to promote H190 helicity on the VLP. In the first strategy, H190 was flanked by GCN4 structure-promoting elements within the antigen module; in the second, dual H190 copies were arrayed as tandem repeats in the module. Molecular dynamics simulation predicted that tandem repeat arraying would minimize secondary structural deviation of modularized H190 from its native conformation. In vivo testing supported this finding, showing that although both modularization strategies conferred high H190-specific immunogenicity, tandem repeat arraying of H190 led to a strikingly higher immune response quality, as measured by ability to generate antibodies recognizing a recombinant HA domain and split influenza virion. These findings provide new insights into the rational engineering of VLP vaccines, and could ultimately enable safe and efficacious vaccine design as an alternative to conventional approaches necessitating pathogen cultivation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. In harmony with gold and uranium

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    A profile is given on Mr Clive Knobbs as managing director of Harmony gold mine. From March 1 1983 he succeeded as deputy chairman of the group's gold and uranium division, and became the Rand Mines representative on the Gold Producers Committee and the Executive Committee of the Chamber of Mines. The article also takes a look at gold and uranium mining in general

  3. 41 CFR 101-45.002 - Gold.

    Science.gov (United States)

    2010-07-01

    ... 41 Public Contracts and Property Management 2 2010-07-01 2010-07-01 true Gold. 101-45.002 Section... PERSONAL PROPERTY § 101-45.002 Gold. (a) Gold will be sold in accordance with this section and part 102-38 of the Federal Management Regulation. (b) Sales of gold shall be processed to— (1) Use the sealed bid...

  4. 41 CFR 102-85.190 - Can GSA Rent be adjusted when standard levels of service are performed by other customer agencies?

    Science.gov (United States)

    2010-07-01

    ... when standard levels of service are performed by other customer agencies? 102-85.190 Section 102-85.190... perform or contract for such services must be obtained in advance by the customer agency from the... of Service § 102-85.190 Can GSA Rent be adjusted when standard levels of service are performed by...

  5. Size fraction assaying of gold bearing rocks (for gold extraction) by ...

    African Journals Online (AJOL)

    A novel method has been developed for processing and extraction of gold from gold bearing rocks for use by small-scale gold miners in Ghana. The methodology involved crushing of gold bearing hard rocks to fine particles to form a composite sample and screening at a range of sizes. Gold distribution in the composite ...

  6. A Point Mutation in p190A RhoGAP Affects Ciliogenesis and Leads to Glomerulocystic Kidney Defects.

    Directory of Open Access Journals (Sweden)

    Katherine Stewart

    2016-02-01

    Full Text Available Rho family GTPases act as molecular switches regulating actin cytoskeleton dynamics. Attenuation of their signaling capacity is provided by GTPase-activating proteins (GAPs, including p190A, that promote the intrinsic GTPase activity of Rho proteins. In the current study we have performed a small-scale ENU mutagenesis screen and identified a novel loss of function allele of the p190A gene Arhgap35, which introduces a Leu1396 to Gln substitution in the GAP domain. This results in decreased GAP activity for the prototypical Rho-family members, RhoA and Rac1, likely due to disrupted ordering of the Rho binding surface. Consequently, Arhgap35-deficient animals exhibit hypoplastic and glomerulocystic kidneys. Investigation into the cystic phenotype shows that p190A is required for appropriate primary cilium formation in renal nephrons. P190A specifically localizes to the base of the cilia to permit axoneme elongation, which requires a functional GAP domain. Pharmacological manipulations further reveal that inhibition of either Rho kinase (ROCK or F-actin polymerization is able to rescue the ciliogenesis defects observed upon loss of p190A activity. We propose a model in which p190A acts as a modulator of Rho GTPases in a localized area around the cilia to permit the dynamic actin rearrangement required for cilia elongation. Together, our results establish an unexpected link between Rho GTPase regulation, ciliogenesis and glomerulocystic kidney disease.

  7. Gold--a controversial sensitizer

    DEFF Research Database (Denmark)

    Bruze, M; Andersen, Klaus Ejner

    1999-01-01

    allergy to gold sodium thiosulfate were published at the beginning of the 1990s, the allergic nature of the reported positive patch test reactions to gold was questioned. The major argument for such questioning was the lack of demonstrable clinical relevance in most positive reactors. A major reason......Until recently, gold allergy was considered to be extremely rare. Gold has been used and worshipped for thousands of years without any obvious complaints of skin problems, either in those participating in mining and other ways of prospecting, or in those wearing jewellery. When studies on contact...... for the questioning may have been confusion in differentiating between contact allergy and allergic contact dermatitis. To arrive at a diagnosis of allergic contact dermatitis, 3 steps have, in principle, to be fulfilled: (i) establishment of contact allergy; (ii) demonstration of present exposure; (iii) assessment...

  8. Gold, currencies and market efficiency

    Science.gov (United States)

    Kristoufek, Ladislav; Vosvrda, Miloslav

    2016-05-01

    Gold and currency markets form a unique pair with specific interactions and dynamics. We focus on the efficiency ranking of gold markets with respect to the currency of purchase. By utilizing the Efficiency Index (EI) based on fractal dimension, approximate entropy and long-term memory on a wide portfolio of 142 gold price series for different currencies, we construct the efficiency ranking based on the extended EI methodology we provide. Rather unexpected results are uncovered as the gold prices in major currencies lay among the least efficient ones whereas very minor currencies are among the most efficient ones. We argue that such counterintuitive results can be partly attributed to a unique period of examination (2011-2014) characteristic by quantitative easing and rather unorthodox monetary policies together with the investigated illegal collusion of major foreign exchange market participants, as well as some other factors discussed in some detail.

  9. Optical trapping of gold aerosols

    DEFF Research Database (Denmark)

    Schmitt, Regina K.; Pedersen, Liselotte Jauffred; Taheri, S. M.

    2015-01-01

    Aerosol trapping has proven challenging and was only recently demonstrated.1 This was accomplished by utilizing an air chamber designed to have a minimum of turbulence and a laser beam with a minimum of aberration. Individual gold nano-particles with diameters between 80 nm and 200 nm were trapped...... in air using a 1064 nm laser. The positions visited by the trapped gold nano-particle were quantified using a quadrant photo diode placed in the back focal plane. The time traces were analyzed and the trapping stiffness characterizing gold aerosol trapping determined and compared to aerosol trapping...... of nanometer sized silica and polystyrene particles. Based on our analysis, we concluded that gold nano-particles trap more strongly in air than similarly sized polystyrene and silica particles. We found that, in a certain power range, the trapping strength of polystyrene particles is linearly decreasing...

  10. Biomass processing over gold catalysts

    CERN Document Server

    Simakova, Olga A; Murzin, Dmitry Yu

    2014-01-01

    The book describes the valorization of biomass-derived compounds over gold catalysts. Since biomass is a rich renewable feedstock for diverse platform molecules, including those currently derived from petroleum, the interest in various transformation routes has become intense. Catalytic conversion of biomass is one of the main approaches to improving the economic viability of biorefineries.  In addition, Gold catalysts were found to have outstanding activity and selectivity in many key reactions. This book collects information about transformations of the most promising and important compounds derived from cellulose, hemicelluloses, and woody biomass extractives. Since gold catalysts possess high stability under oxidative conditions, selective oxidation reactions were discussed more thoroughly than other critical reactions such as partial hydrogenation, acetalization, and isomerization. The influence of reaction conditions, the role of the catalyst, and the advantages and disadvantages of using gold are pre...

  11. The alpha-branching ratios of the 188,190,192Pb isotopes

    International Nuclear Information System (INIS)

    Wauters, J.; Dendooven, P.; Decrock, P.; Huyse, M.; Reusen, G.; Duppen, P. van

    1992-01-01

    The α-branching ratios (b α ) of 192,190,188 Pb are measured using mass-separated sources. Different experimental set-ups are used - one detector as well as two detector set-ups - thereby detecting the α particles from the parent and/or via α decay formed daughter nuclei, the β-delayed gamma radiation from the parent and/or via β decay formed daughter nuclei in the Tl KX Rays from electron capture decay. Values for b α of 6.2(6) 10 -5 and 4.0(4) 10 -3 were found for 191,190 Pb respectively. For 188 Pb, limits on the b α values were obtained: 0.03 α α values showed that the discrepancies in the b α values were not due to inadequate correction procedures, as was suggested, but to experimental uncertainties in the efficiency determination of the different detection set-ups and to an unreliable β-decay scheme for 188 Pb. The b α obtained in this work show that the lead α decay is not faster than the Hg α decay and that there is no need to assume a disappearance of the Z=82 shell closure halfway between N=82 and N=126. (orig.)

  12. Exotic superdeformed structure in A∼190 nuclei observed using Eurogam2

    International Nuclear Information System (INIS)

    Wilson, A.N.; Timar, J.; Bergstroem, M.; Paul, E.S.; Bouneau, S.; Azaiez, F.; Korichi, A.; Nakatsukasa, T.

    1995-01-01

    Dipole transitions between superdeformed rotational bands are only very rarely observed due to the competition from the very strong in-band E2 decays. We have carried out two experiments with the EUROGAM2 γ-ray spectrometer, situated at the Vivitron tandem accelerator at CRN Strasbourg, in September and October 1994. In the first experiment we observe M1 dipole transitions between the signature partner yrast superdeformed bands in 193 Tl. This measurement gives a mean value of (g K -g R ) K/Q o = 0.135 ± 0.010 μ N /eb identifying the bands as belonging to the (642)5/2 single particle orbital. We also observe 5 additional new superdeformed bands in 193 Tl, whose structures are discussed. In the second experiment we observe three transitions, at 911, 865 and 831 keV, which link an excited superdeformed band in 190 Hg to the yrast superdeformed band. The data suggest that these are stretched dipole transitions with E1 multipolarity and strengths of about 10 -3 Wu. This is the first observation of a collective vibration of the superdeformed mean field. We also observe two new superdeformed bands in 190 Hg. (authors). 39 refs., 11 figs., 3 tabs

  13. Infants 1-90 days old hospitalized with human rhinovirus infection.

    Science.gov (United States)

    Bender, Jeffrey M; Taylor, Charla S; Cumpio, Joven; Novak, Susan M; She, Rosemary C; Steinberg, Evan A; Marlowe, Elizabeth M

    2014-09-01

    Human rhinovirus (HRV) is a common cause of respiratory illness in children. The impact of HRV infection on 1- to 90-day-old infants is unclear. We hypothesized that HRV infection would be clinically similar to respiratory syncytial virus (RSV) infection in the hospitalized infants. We conducted a retrospective study of hospitalized infants, who were 1-90 days old, with HRV or RSV within the Southern California Kaiser Permanente network over a 1-year period (August 2010 to October 2011). We identified 245 hospitalized infants who underwent respiratory virus testing. HRV was found in 52 infants (21%) compared to 79 infants (32%) with RSV (P = 0.008). Infants with HRV infection experienced longer hospital stays compared to those with RSV (median length of stay 4 days vs. 3 days, P = 0.009) and had fewer short hospital stays ≤3 days (P = 0.029). There was a trend in infants with HRV infection to be younger (P = 0.071) and have more fevers (P = 0.052). Recent advances in diagnostics allow for identification of a broad range of viral pathogens in infants. Compared to RSV, HRV was associated with longer hospital stays. Additional studies and improved, more specific testing, methods are needed to further define the effects of HRV infection in infants 1-90 days old. © 2014 Wiley Periodicals, Inc.

  14. Isomers in neutron-rich A ∼ 190 nuclides from 208Pb fragmentation

    International Nuclear Information System (INIS)

    Rykaczewski, Krzysztof Piotr; Caamano, M.; Banu, A.; Walker, P.M.; Morton, N.H.; Regan, P. H.; Regan, Patrick H; Pfutzner, M.; Podolyak, Zs.; Gerl, J.; Hellstrom, M.; Mayet, P.; Miernik, K.; Mineva, M.N.; Aprahamian, A.; Benlliure, J.; Bruce, A.M.; Butler, P.A.; Cortina Gil, D.; Cullen, D.M.; Doring, J.; Enqvist, T.; Fox, C.; Garces Narro, J.; Geissel, H.; Gelletly, W.; Giovinazzo, J.; Gorska, M.; Grawe, H.; Grzywacz, R.; Kleinbohl, A.; Korten, W.; Lewitowicz, M.; Lucas, R.; Mach, H.; O'Leary, C.D.; De Oliveira, F.; Pearson, C.J.; Rejmund, F.

    2004-01-01

    Relativistic projectile fragmentation of 208 Pb has been used to produce isomers in neutron-rich, A ∼ 190 nuclides. A forward-focusing spectrometer provided ion-by-ion mass and charge identification. The detection of gamma-rays emitted by stopped ions has led to the assignment of isomers in 188 Ta, 190 W, 192 Re, 193 Re, 195 Os, 197 Ir, 198 Ir, 200 Pt, 201 Pt, 202 Pt and 203 Au, with half-lives ranging from approximately 10 ns to 1 ms. Tentative isomer information has been found also for 174 Er, 175 Er, 185 Hf, 191 Re, 194 Re and 199 Ir. In most cases, time-correlated, singles gamma-ray events provided the first spectroscopic data on excited states for each nuclide. In 200 Pt and 201 Pt, the assignments are supported by gamma-gamma coincidences. Isomeric ratios provide additional information, such as half-life and transition energy constraints in particular cases. The level structures of the platinum isotopes are discussed, and comparisons are made with isomer systematics

  15. Improvement of strain Penicillium sp. EZ-ZH190 for tannase production by induced mutation.

    Science.gov (United States)

    Zakipour-Molkabadi, E; Hamidi-Esfahani, Z; Sahari, M A; Azizi, M H

    2013-11-01

    In the search for an efficient producer of tannase, Penicillium sp. EZ-ZH190 was subjected to mutagenesis using heat treatment and strain EZ-ZH290 was isolated. The maximum tannase in this mutant strain was 4.32 U/mL with an incubation period of 84 h as compared to wild strain EZ-ZH190 where the incubation period was 96 h with a maximum enzyme activity of 4.33 U/mL. Also, the Penicillium sp. EZ-ZH290 tannase had a maximum activity at 40 °C and pH 5.5. Then, the spores of strain EZ-ZH290 were subjected to γ irradiation mutagenesis and strain EZ-ZH390 was isolated. Strain EZ-ZH390 exhibited higher tannase activity (7.66 U/mL) than the parent strain EZ-ZH290. It was also found that Penicillium sp. EZ-ZH390 tannase had an optimum activity at 35 °C and a broad pH profile with an optimum at pH 5.5. The tannase pH stability of Penicillium sp. EZ-ZH390 and its maximum production of tannase followed the same trend for five generations confirming the occurrence of stable mutant. This paper is shown that γ irradiation can mutate the Penicillium sp. leading to increase the tannase production.

  16. Immunological properties of gold nanoparticles

    OpenAIRE

    Dykman, Lev A.; Khlebtsov, Nikolai G.

    2016-01-01

    In the past decade, gold nanoparticles have attracted strong interest from the nanobiotechnological community owing to the significant progress made in robust and easy-to-make synthesis technologies, in surface functionalization, and in promising biomedical applications. These include bioimaging, gene diagnostics, analytical sensing, photothermal treatment of tumors, and targeted delivery of various biomolecular and chemical cargos. For the last-named application, gold nanoparticles should be...

  17. Biosensors based on gold nanostructures

    OpenAIRE

    Vidotti,Marcio; Carvalhal,Rafaela F.; Mendes,Renata K.; Ferreira,Danielle C. M.; Kubota,Lauro T.

    2011-01-01

    The present review discusses the latest advances in biosensor technology achieved by the assembly of biomolecules associated with gold nanoparticles in analytical devices. This review is divided in sections according to the biomolecule employed in the biosensor development: (i) immunocompounds; (ii) DNA/RNA and functional DNA/RNA; and (iii) enzymes and Heme proteins. In order to facilitate the comprehension each section was subdivided according to the transduction mode. Gold nanoparticles bas...

  18. Characterisation of gold from Fiji

    OpenAIRE

    Naden, Jon; Henney, P.J.

    1995-01-01

    This is a study of the variation in chemistry and inclusion mineralogy of bedrock and placer gold from Fiji. It forms part of a large project, undertaking gold characterisation from a wide range of geological environments in Ecuador, Zimbabwe, Malaysia and Fiji. The work was carried out under the Overseas Development AdministratiodBritish Geological Survey Technology Development and Research programme (Project R5549) as part of the British Government’s provision of technical...

  19. Goldenphilicity: Luminescent gold compounds

    International Nuclear Information System (INIS)

    Sansores, L.E.

    2002-01-01

    In the solids and molecules different types of bonds are presented depending on the involved atoms, covalent bonds are common among elements of open shell, where more bond orbitals are filled than anti bond orbitals. It is expected that ionic bonds among closed shell atoms which have charges of opposite sign. Bonds type Van der Waals are presented among molecules which have a bipolar moment. It would not be expected bonds among zero charge species, or more generally with the same nominal charge and in any case the attractive forces would be very small. In fact it is expected that two metallic cations to be repelled each other. There recently is evidence that in organic or organometallic compounds could exist attractive interactions between two cations of the d 8 -d 10 -s 2 families. These bonds are weak but stronger than those of Van der Waals. They are compared with the hydrogen bonds. In this work it was reviewed some examples in which the goldenphilicity plays an important role in the luminescence that the gold complexes present. Examples of mono, bi and trinuclear and the structures that these organometallic compounds could take are examined. (Author)

  20. Structure and bonding in gold compounds

    International Nuclear Information System (INIS)

    Parish, R.V.

    1988-01-01

    Recent developments in chemical applications of 197 Au Moessbauer spectroscopy are reviewed. For gold(I) and gold(III), systematic variations in isomer shift and quadrupole splitting are seen as the ligands are changed; the effects of change in coordination number of the gold atoms are also systematic. Data for gold(II) systems involving gold-gold bonds lie between those for corresponding gold(I) and gold(III) materials, showing a small increase in isomer shift and a larger increase in quadrupole splitting as the oxidation state decreases; these trends are explained in terms of the structures. Data for mixed-metal cluster compounds are much more sensitive to structural effects than in homonuclear clusters. Both sets of data show systematic changes with increase in the number of metal atoms to which the gold atom is bound. The connectivity also influences the recoil-free fraction. (orig.)

  1. Robust zero resistance in a superconducting high-entropy alloy at pressures up to 190 GPa

    Science.gov (United States)

    Guo, Jing; Wang, Honghong; von Rohr, Fabian; Wang, Zhe; Cai, Shu; Zhou, Yazhou; Yang, Ke; Li, Aiguo; Jiang, Sheng; Wu, Qi; Cava, Robert J.; Sun, Liling

    2017-12-01

    We report the observation of extraordinarily robust zero-resistance superconductivity in the pressurized (TaNb)0.67(HfZrTi)0.33 high-entropy alloy--a material with a body-centered-cubic crystal structure made from five randomly distributed transition-metal elements. The transition to superconductivity (TC) increases from an initial temperature of 7.7 K at ambient pressure to 10 K at ˜60 GPa, and then slowly decreases to 9 K by 190.6 GPa, a pressure that falls within that of the outer core of the earth. We infer that the continuous existence of the zero-resistance superconductivity from 1 atm up to such a high pressure requires a special combination of electronic and mechanical characteristics. This high-entropy alloy superconductor thus may have a bright future for applications under extreme conditions, and also poses a challenge for understanding the underlying quantum physics.

  2. Predicting superdeformed rotational band-head spin in A ∼ 190 ...

    Indian Academy of Sciences (India)

    Table1 Shi2 ab3. Becker4 CBM5 SAM6 Zeng7. 191Au(b1). 187. 184.6. 1.5. 0.1185. 9.5. 9.5. 7.5. 7.5. –. 7.5. 7.5. 7.5. 191Au(b2). 398. 398.7. 8.4. 0.0928. 17.5. 17.5 17.5. 17.5. –. 17.5. 17.5 17.5. 191Au(b3). 383. 383.3. 7.4. 0.0916. 16.5. 16.5 17.5. 17.5. –. 16.5. 16.5 16.5. 190Hg(b1). 317. 316.8. 6.8. 0.0834. 12. 12. 13. 13. 12.

  3. The effectiveness of heat pumps as part of CCGT-190/220 Tyumen CHP-1

    Directory of Open Access Journals (Sweden)

    Tretyakova Polina

    2017-01-01

    Full Text Available The article considers the possibility of increasing the energy efficiency of CCGT-190/220 Tyumen CHP-1 due to the utilization of low-grade heat given off in the condenser unit of the steam turbine. To assess the effectiveness of the proposed system, the indexes of thermal efficiency are given. As a result of a research the following conclusions are received: The heat-transfer agent heat pump, when heated uses low-grade heat TPP and increases heat output, but consumes the electricity. Using a heat pump is effective for a small temperature difference between the condenser and the evaporator. Good example is heating water before chemical treatment. This method is more efficient than using a replacement boiler and it is used in steam selection.

  4. α-decay properties of 190Po and the identification of 191Po

    International Nuclear Information System (INIS)

    Batchelder, J.C.; Batchelder, J.C.; Zganjar, E.F.; Toth, K.S.; Bingham, C.R.; Bingham, C.R.; Wauters, J.; Brown, L.T.; Davids, C.N.; Seweryniak, D.; Brown, L.T.; Conticchio, L.F.; Seweryniak, D.; Conticchio, L.F.; Wood, J.L.

    1997-01-01

    The α-decay properties of 190 Po were investigated through the use of a fragment mass analyzer in conjunction with a double-sided Si strip detector. The isotope was produced via the 96 Mo( 96 Mo,2n) reaction, and its α-decay energy and T 1/2 were measured as 7529(10) keV and 2.4 -0.3 +0.4 ms, respectively. The resulting reduced width is nearly identical to that of the 192,194 Po isotopes. This is believed to result from significant mixing between the ground state π(2p) and the low-lying 0 + π(4p-2h) intruder state in the Po parent. The result provides further evidence for shape coexistence in the light Po isotopes. In addition, 191 Po was unambiguously identified, and the 186 Pb α-decay branch was determined experimentally for the first time. copyright 1997 The American Physical Society

  5. Individual and collective excitations in the superdeformed nuclei of the 190 mass region; Excitations individuelles et collectives dans les noyaux superdeformes de la region de masse 190

    Energy Technology Data Exchange (ETDEWEB)

    Bouneau, Sandra [Inst. de Physique Nucleaire, Paris-11 Univ., 91 - Orsay (France)

    1997-04-11

    This work aims at the study of different excitation modes, individual and collective, in superdeformed (SD) nuclei in the mass 190 region. The study of {sup 193}Tl and {sup 195,196,197}Bi SD nuclei brought information concerning individual excitation around the proton and neutron SD gaps Z = 80 - 82 and N = 112. Also, the study of the nucleus {sup 196}Pb revealed excited SD states built on collective vibrations. Concerning the isotope {sup 193}Tl, magnetic property analysis has been performed and allowed us to identify the proton intruder orbital {pi}i{sub 13/2} on which the two known SD the bands of the nucleus are build. It was possible to separate experimentally the relative contribution of proton and neutron pairing to the dynamic moment of inertia. Several {gamma} transition of high energy (about 3 MeV) linking SD states to normal deformed states (ND) and three new SD bands have been found in this nucleus. These SD bands have been interpreted in terms of individual excitations of the single proton on different orbitals identified above the proton SD gap Z = 80. An interaction between the states of two excited SD band have been observed and its strength measured. All these results (gyromagnetic factor, the role of nuclear pairing, excitation energy of the SD well, the interaction between two orbitals) represent information of theoretical interest. In each isotope {sup 195-197}Bi, one SD band has been discovered. They have been also interpreted in terms of individual excitation implying the same proton state. The study of this nuclei brought the first experimental proof that the superdeformation phenomenon persists above the shell closure Z = 82. In {sup 196}Pb nucleus a new excited SD band has been discovered. Observations are mentioned suggesting that we have to consider excitations different from those based on individual ones. An interpretation based on vibrational modes can explain both the low energy measured of the excited states in respect with the SD

  6. New isomers in the neutron-rich A∼190 mass region

    International Nuclear Information System (INIS)

    Caamano, M.

    2002-02-01

    Previously unobserved isomeric states in 188 Ta, 190 W, 192 Re, 193 Re, 195 Os, 197 Ir, 198 Ir, 200 Pt, 201 Pt, 202 Pt and 203 Au, with half-lives ranging from 10 ns to 290 μs have been populated and studied using a fragmentation reaction in conjunction with a forward focussing spectrometer. In most cases, this provided the first ever spectroscopic data made available for the nucleus, and 200 Pt presented the first new seniority 4 state, on the basis of γ-γ coincidences, following a fragmentation reaction. Half-lives have been measured and tentative level schemes have been drawn for each isomer, spins and parities being consistent with blocked BCS calculations, hindrance factors, systematics and the relative intensities of γ-rays and X-rays (where possible). Isomeric ratios have been measured, values ranging from 1 % to 64 %. Potential Energy Surface calculations were performed in parallel to the blocked BCS calculations, in order to provide deformation parameters, excitation energies and quasiparticle configurations. Ground state (or lowest level) shape calculations reveal a change from axially symmetric, through triaxial, to spherical shapes across the data set, from 188 Ta to 203 Au, as 208 Pb is approached. Weisskopf hindrance factors provide evidence for the erosion of the goodness of the K-quantum number, compatible with soft or axially symmetric shapes. The prolate-oblate phase transition region, with respect to tungsten, osmium and platinum, shows 195 Os to be the pivotal nucleus in the osmium isotopic chain, with a calculated triaxial ground state. On comparison with the systematics of the region, results obtained for 190 W show evidence for a Z ≤ 74 sub-shell closure, analogous to that at Z = 64. Finally, new isotopes, 167 Tb, 170 Dy and 199 Ir were discovered. (author)

  7. Annealing relaxation of ultrasmall gold nanostructures

    Science.gov (United States)

    Chaban, Vitaly

    2015-01-01

    Except serving as an excellent gift on proper occasions, gold finds applications in life sciences, particularly in diagnostics and therapeutics. These applications were made possible by gold nanoparticles, which differ drastically from macroscopic gold. Versatile surface chemistry of gold nanoparticles allows coating with small molecules, polymers, biological recognition molecules. Theoretical investigation of nanoscale gold is not trivial, because of numerous metastable states in these systems. Unlike elsewhere, this work obtains equilibrium structures using annealing simulations within the recently introduced PM7-MD method. Geometries of the ultrasmall gold nanostructures with chalcogen coverage are described at finite temperature, for the first time.

  8. Phage based green chemistry for gold ion reduction and gold retrieval.

    Science.gov (United States)

    Setyawati, Magdiel I; Xie, Jianping; Leong, David T

    2014-01-22

    The gold mining industry has taken its toll on the environment, triggering the development of more environmentally benign processes to alleviate the waste load release. Here, we demonstrate the use of bacteriophages (phages) for biosorption and bioreduction of gold ions from aqueous solution, which potentially can be applied to remediate gold ions from gold mining waste effluent. Phage has shown a remarkably efficient sorption of gold ions with a maximum gold adsorption capacity of 571 mg gold/g dry weight phage. The product of this phage mediated process is gold nanocrystals with the size of 30-630 nm. Biosorption and bioreduction processes are mediated by the ionic and covalent interaction between gold ions and the reducing groups on the phage protein coat. The strategy offers a simple, ecofriendly and feasible option to recover of gold ions to form readily recoverable products of gold nanoparticles within 24 h.

  9. Gold nanoparticles stabilized by chitosan

    International Nuclear Information System (INIS)

    Geraldes, Adriana N.; Oliveira, Maria Jose A.; Silva, Andressa A. da; Leal, Jessica; Batista, Jorge G.S.; Lugao, Ademar B.

    2015-01-01

    In our laboratory has been growing the interest in studying gold nanoparticles and for this reason, the aim of this work is report the first results of the effect of chitosan as stabilizer in gold nanoparticle formulation. AuNPs were synthesized by reducing hydrogen tetrachloroaurate (HAuCl 4 ) using NaBH 4 or gamma irradiation (25kGy) as reduction agent. The chitosan (3 mol L -1 ) was added at 0.5; 1.0 and 1.5 mL. The gold nanoparticles were characterized by UV-Vis absorption spectroscopy, X-ray diffraction (XRD) and Transmission electron microscopy (TEM). Their physical stability was determined using a UV-Vis spectrophotometer over one week during storage at room temperature. Absorption measurements indicated that the plasmon resonance wavelength appears at a wavelength around 530 nm. Has been observed that Chitosan in such quantities were not effective in stabilizing the AuNPs. (author)

  10. Plasmonic Horizon in Gold Nanosponges.

    Science.gov (United States)

    Vidal, Cynthia; Sivun, Dmitry; Ziegler, Johannes; Wang, Dong; Schaaf, Peter; Hrelescu, Calin; Klar, Thomas A

    2018-02-14

    An electromagnetic wave impinging on a gold nanosponge coherently excites many electromagnetic hot-spots inside the nanosponge, yielding a polarization-dependent scattering spectrum. In contrast, a hole, recombining with an electron, can locally excite plasmonic hot-spots only within a horizon given by the lifetime of localized plasmons and the speed carrying the information that a plasmon has been created. This horizon is about 57 nm, decreasing with increasing size of the nanosponge. Consequently, photoluminescence from large gold nanosponges appears unpolarized.

  11. New Trends in Gold Catalysts

    Directory of Open Access Journals (Sweden)

    Leonarda F. Liotta

    2014-07-01

    Full Text Available Gold is an element that has fascinated mankind for millennia. The catalytic properties of gold have been a source of debate, due to its complete chemical inertness when in a bulk form, while it can oxidize CO at temperatures as low as ~200 K when in a nanocrystalline state, as discovered by Haruta in the late 1980s [1]. Since then, extensive activity in both applied and fundamental research on gold has been initiated. The importance of the catalysis by gold represents one of the fasted growing fields in science and is proven by the promising applications in several fields, such as green chemistry and environmental catalysis, in the synthesis of single-walled carbon nanotubes, as modifiers of Ni catalysts for methane steam and dry reforming reactions and in biological and electrochemistry applications. The range of reactions catalyzed by gold, as well as the suitability of different supports and the influence of the preparation conditions have been widely explored and optimized in applied research [2]. Gold catalysts appeared to be very different from the other noble metal-based catalysts, due to their marked dependence on the preparation method, which is crucial for the genesis of the catalytic activity. Several methods, including deposition-precipitation, chemical vapor deposition and cation adsorption, have been applied for the preparation of gold catalysts over reducible oxides, like TiO2. Among these methods, deposition-precipitation has been the most frequently employed method for Au loading, and it involves the use of tetrachloroauric (III acid as a precursor. On the other hand, the number of articles dealing with Au-loaded acidic supports is smaller than that on basic supports, possibly because the deposition of [AuCl4]− or [AuOHxCl4−x]− species on acidic supports is difficult, due to their very low point of zero charge. Despite this challenge, several groups have reported the use of acidic zeolites as supports for gold. Zeolites

  12. A Novel Strategy for Synthesis of Gold Nanoparticle Self Assemblies

    NARCIS (Netherlands)

    Verma, Jyoti; Lal, Sumit; van Veen, Henk A.; van Noorden, Cornelis J. F.

    2014-01-01

    Gold nanoparticle self assemblies are one-dimensional structures of gold nanoparticles. Gold nanoparticle self assemblies exhibit unique physical properties and find applications in the development of biosensors. Methodologies currently available for lab-scale and commercial synthesis of gold

  13. Ligations of Gold Atoms with Iron Porphyrin

    DEFF Research Database (Denmark)

    Zhang, Ling; Kepp, Kasper Planeta; Ulstrup, Jens

    Gold is an exotic material with d-electrons deciding electronic mappings andconfigurations of adsorbed molecules. The specific interaction of Au atoms and S-, Ncappedmolecules make gold nanoparticles widely applied in the medicine transport andimmunoassay. Density functional theory demonstrates t...

  14. Metallic gold beads in hyaluronic acid

    DEFF Research Database (Denmark)

    Pedersen, Dan Sonne; Tran, Thao Phuong; Smidt, Kamille

    2013-01-01

    . In conclusion, our findings support that bio-liberation of gold from metallic gold surfaces have anti-inflammatory properties similar to classic gold compounds, warranting further studies into the pharmacological potential of this novel gold-treatment and the possible synergistic effects of hyaluronic acid....... by exploiting macrophage-induced liberation of gold ions (dissolucytosis) from gold surfaces. Injecting gold beads in hyaluronic acid (HA) as a vehicle into the cavities of the brain can delay clinical signs of disease progression in the MS model, experimental autoimmune encephalitis (EAE). This study...... investigates the anti-inflammatory properties of metallic gold/HA on the gene expression of tumor necrosis factor (Tnf-α), Interleukin (Il)-1β, Il-6, Il-10, Colony-stimulating factor (Csf)-v2, Metallothionein (Mt)-1/2, Bcl-2 associated X protein (Bax) and B cell lymphoma (Bcl)-2 in cultured J774 macrophages...

  15. Shapes of the $^{192,190}$Pb ground states from beta decay studies using the total absorption technique

    CERN Document Server

    Estevez Aguado, M.E.; Agramunt, J.; Rubio, B.; Tain, J.L.; Jordan, D.; Fraile, L.M.; Gelletly, W.; Frank, A.; Csatlos, M.; Csige, L.; Dombradi, Zs.; Krasznahorkay, A.; Nacher, E.; Sarriguren, P.; Borge, M.J.G.; Briz, J.A.; Tengblad, O.; Molina, F.; Moreno, O.; Kowalska, M.; Fedosseev, V.N.; Marsh, B.A.; Fedorov, D.V.; Molkanov, P.L.; Andreyev, A.N.; Seliverstov, M.D.; Burkard, K.; Huller, W.

    2015-01-01

    The beta decay of $^{192,190}$Pb has been studied using the total absorption technique at the ISOLDE(CERN) facility. The beta-decay strength deduced from the measurements, combined with QRPA theoretical calculations, allow us to infer that the ground states of the $^{192,190}$Pb isotopes are spherical. These results represent the first application of the shape determination method using the total absorption technique for heavy nuclei and in a region where there is considerable interest in nuclear shapes and shape effects.

  16. The geology of the gold deposits of Prestea gold belt of Ghana ...

    African Journals Online (AJOL)

    This paper presents the geology of the gold deposits along the Prestea gold belt of Ghana to assist exploration work for new orebodies along the belt. Prestea district is the third largest gold producer in West Africa after Obuasi and Tarkwa districts (over 250 metric tonnes Au during the last century). The gold deposits are ...

  17. Gold Nanoparticle Mediated Phototherapy for Cancer

    International Nuclear Information System (INIS)

    Yao, C.; Zhang, L.; Wang, J.; He, Y.; Xin, J.; Wang, S.; Xu, H.; Zhang, Z.

    2016-01-01

    Gold nanoparticles exhibit very unique physiochemical and optical properties, which now are extensively studied in range of medical diagnostic and therapeutic applications. In particular, gold nanoparticles show promise in the advancement of cancer treatments. This review will provide insights into the four different cancer treatments such as photothermal therapy, gold nanoparticle-aided photodynamic therapy, gold nanoparticle-aided radiation therapy, and their use as drug carrier. We also discuss the mechanism of every method and the adverse effects and its limitations

  18. Phanerozoic continental growth and gold metallogeny of Asia

    Science.gov (United States)

    Goldfarb, Richard J.; Taylor, Ryan D.; Collins, Gregory S.; Goryachev, Nicolay A.; Orlandini, Omero Felipe

    2014-01-01

    The Asian continent formed during the past 800 m.y. during late Neoproterozoic through Jurassic closure of the Tethyan ocean basins, followed by late Mesozoic circum-Pacific and Cenozoic Himalayan orogenies. The oldest gold deposits in Asia reflect accretionary events along the margins of the Siberia, Kazakhstan, North China, Tarim–Karakum, South China, and Indochina Precambrian blocks while they were isolated within the Paleotethys and surrounding Panthalassa Oceans. Orogenic gold deposits are associated with large-scale, terrane-bounding fault systems and broad areas of deformation that existed along many of the active margins of the Precambrian blocks. Deposits typically formed during regional transpressional to transtensional events immediately after to as much as 100 m.y. subsequent to the onset of accretion or collision. Major orogenic gold provinces associated with this growth of the Asian continental mass include: (1) the ca. 750 Ma Yenisei Ridge, ca. 500 Ma East Sayan, and ca. 450–350 Ma Patom provinces along the southern margins of the Siberia craton; (2) the 450 Ma Charsk belt of north-central Kazakhstan; (3) the 310–280 Ma Kalba belt of NE Kazakhstan, extending into adjacent NW Xinjiang, along the Siberia–Kazakhstan suture; (4) the ca. 300–280 Ma deposits within the Central Asian southern and middle Tien Shan (e.g., Kumtor, Zarmitan, Muruntau), marking the closure of the Turkestan Ocean between Kazakhstan and the Tarim–Karakum block; (5) the ca. 190–125 Ma Transbaikal deposits along the site of Permian to Late Jurassic diachronous closure of the Mongol–Okhotsk Ocean between Siberia and Mongolia/North China; (6) the probable Late Silurian–Early Devonian Jiagnan belt formed along the margin of Gondwana at the site of collision between the Yangtze and Cathaysia blocks; (7) Triassic deposits of the Paleozoic Qilian Shan and West Qinling orogens along the SW margin of the North China block developed during collision of South China

  19. Highly active thermally stable nanoporous gold catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Biener, Juergen; Wittstock, Arne; Biener, Monika M.; Bagge-Hansen, Michael; Baeumer, Marcus; Wichmann, Andre; Neuman, Bjoern

    2016-12-20

    In one embodiment, a system includes a nanoporous gold structure and a plurality of oxide particles deposited on the nanoporous gold structure; the oxide particles are characterized by a crystalline phase. In another embodiment, a method includes depositing oxide nanoparticles on a nanoporous gold support to form an active structure and functionalizing the deposited oxide nanoparticles.

  20. Gold and Silver Extraction from Leach Solutions

    OpenAIRE

    Bagdaulet K. Kenzhaliyev; Renata R. Iskhakova; Zamzagul D. Dosymbaeva; Esen N. Sulejmenov

    2014-01-01

    There has been carried out an investigation on the extraction of gold and silver from thiosulfate solutions: standard test and technological solutions of chemical and electrochemical leaching. The influence of related metals on the process of extracting gold from solution was studied. There has been conducted a comparative study of the IR spectra of solutions after the sorption of gold, silver and related metals.

  1. Cancer caused by radioactive gold rings

    International Nuclear Information System (INIS)

    Callary, E.M.

    1989-01-01

    Two recent cases of skin cancer caused by radioactive gold rings are described. The gold was contaminated with radon daughters from hollow goldseeds used to hold radon, back in the 1930s or possibly later. Other radioactive gold rings are probably being worn. The Canadian AECB offers free testing

  2. Ultrafast vibrations of gold nanorings

    DEFF Research Database (Denmark)

    Kelf, T; Tanaka, Y; Matsuda, O

    2011-01-01

    We investigate the vibrational modes of gold nanorings on a silica substrate with an ultrafast optical technique. By comparison with numerical simulations, we identify several resonances in the gigahertz range associated with axially symmetric deformations of the nanoring and substrate. We...

  3. Ultrafast vibrations of gold nanorings

    DEFF Research Database (Denmark)

    Kelf, T; Tanaka, Y; Matsuda, O

    2011-01-01

    We investigate the vibrational modes of gold nanorings on a silica substrate with an ultrafast optical technique. By comparison with numerical simulations, we identify several resonances in the gigahertz range associated with axially symmetric deformations of the nanoring and substrate. We elucid...

  4. Room temperature ferromagnetism of nanocrystalline Nd1.90Ni0.10O3-δ

    Science.gov (United States)

    Sarkar, B. J.; Mandal, J.; Dalal, M.; Bandyopadhyay, A.; Chakrabarti, P. K.

    2018-05-01

    Nanocrystalline sample of Ni2+ doped neodymium oxide (Nd1.90Ni0.10O3-δ, NNO) is synthesized by co-precipitation method. Analysis of X-ray diffraction (XRD) pattern by Rietveld refinement method confirms the desired phase of NNO and complete substitution of Ni2+ ions in the Nd2O3 lattice. Analyses of transmission electron microscopy (TEM) and Raman spectroscopy of NNO recorded at room temperature (RT) also substantiate this fact. Besides, no traces of impurities are found in the analyses of XRD, TEM and Raman data. Room temperature hysteresis loop of NNO suggests the presence of weak ferromagnetism (FM) in low field region ( 600 mT), but in high field region paramagnetism of the host is more prominent. Magnetization vs. temperature ( M- T) curve in the entire temperature range (300-5 K) is analyzed successfully by a combined equation generated from three-dimensional (3D) spin wave model and Curie-Weiss law, which suggests the presence of mixed paramagnetic phase together with ferromagnetic phase in the doped sample. The onset of magnetic ordering is analyzed by oxygen vacancy mediated F-center exchange (FCE) coupling mechanism.

  5. Neutron-deuteron analyzing power data at 19.0 MeV

    International Nuclear Information System (INIS)

    Weisel, G. J.; Tornow, W.; Crowe, B. J. III; Crowell, A. S.; Esterline, J. H.; Howell, C. R.; Kelley, J. H.; Macri, R. A.; Pedroni, R. S.; Walter, R. L.; Witala, H.

    2010-01-01

    Measurements of neutron-deuteron (n-d) analyzing power A y (θ) at E n =19.0 MeV are reported at 16 angles from θ c.m. =46.7 to 152.0 deg. The objective of the experiment is to better characterize the discrepancies between n-d data and the predictions of three-nucleon calculations for neutron energies above 16.0 MeV. The experiment used a shielded neutron source, which produced polarized neutrons via the 2 H(d-vector,n-vector) 3 He reaction, a deuterated liquid scintillator center detector (CD) and liquid-scintillator neutron side detectors. A coincidence between the CD and the side detectors isolated the elastic-scattering events. The CD pulse height spectrum associated with each side detector was sorted by using pulse-shape discrimination, time-of-flight techniques, and by removing accidental coincidences. A Monte Carlo computer simulation of the experiment accounted for effects due to finite geometry, multiple scattering, and CD edge effects. The resulting high-precision data (with absolute uncertainties ranging from 0.0022 to 0.0132) have a somewhat lower discrepancy with the predictions of three-body calculations, as compared to those found at lower energies.

  6. Synthetical analysis of the spin assignment for the superdeformed bands in A≅190 region

    International Nuclear Information System (INIS)

    Di Yaomin

    2002-01-01

    The spin assignment for the superdeformed bands of even-even nuclei in A ≅190 region is given by means of using the method of synthetical analysis. The I( I + 1) expression is used to fit the experimental data of the transition γ energies. In contrast to other procedure, the convergence process of the series expansions is put stress upon, whereas taking how many terms exactly in the expression does not emphasized. Moreover as well as the method of fitting the physical quantity, by use of these series expansions the moment of inertia of band heads is also calculated and then the systematics is used for the spin assignments. In practice, when the experimental data is abundant the systematics of the moment of inertia of band heads is more efficient than the method of fitting the physical quantity in the spin assignment. As for a few bands which spin assignment is difficult, the deviation from the typical rotational bands must be considered, which may be judged easily from the second class of moment of inertia of the bands. Finally the results of the spin assignment and the comparison with other literature are presented. These results should be more reliable

  7. The decay-out of superdeformed bands in the A = 190 region. What have we learned?

    International Nuclear Information System (INIS)

    Lauritsen, T.; Hackman, G.; Khoo, T.L.; Carpenter, M.P.; Janssens, R.V.F.; Ackermann, D.; Ahmad, I.; Blumenthal, D.J.; Lopez-Martens, A.

    1997-01-01

    One-step decay transitions linking the superdeformed (SD) bands 1 and 3 in 194 Hg to yrast levels are discussed. Inter-band transitions between bands 1 and 3 have also been identified. For the first time, the spin, parity and excitation energy have been determined for two SD bands in the same nucleus. The low excitation energy of the excited band supports the view that it is based on an octupole excitation. It is believed that Porter-Thomas fluctuations play a major role in determining the strength of the one-step transitions as suggested by the fact that only one other SD band has been linked in the A = 190 mass region ( 194 Pb) at the present time. When Porter-Thomas fluctuations prevent the observation of one-step or two-step linking transitions, as e.g. in the case of 192 Hg, the analysis of the quasi-continuous part of the decay-out spectrum provides an alternative method for the determination of the excitation energy and spin of an SD band. This method is discussed in detail. (author)

  8. Dose calculations for the concrete water tunnels at 190-C Area, Hanford Site

    International Nuclear Information System (INIS)

    Kamboj, S.; Yu, C.

    1997-01-01

    The RESRAD-BUILD code was used to calculate the radiological dose from the contaminated concrete water tunnels at the 190-C Area at the Hanford Site. Two exposure scenarios, recreationist and maintenance worker, were considered. A residential scenario was not considered because the material was assumed to be left intact (i.e., the concrete would not be rubbleized because the location would not be suitable for construction of a house). The recreationist was assumed to use the tunnel for 8 hours per day for 1 week as an overnight shelter. The maintenance worker was assumed to spend 20 hours per year working in the tunnel. Six exposure pathways were considered in calculating the dose. Three external exposure pathways involved penetrating radiation emitted directly from the contaminated tunnel floor, emitted from radioactive particulates deposited on the tunnel floor, and resulting from submersion in airborne radioactive particulates. Three internal exposure pathways involved inhalation of airborne radioactive particulates; inadvertent direct ingestion of removable, contaminated material on the tunnel floor; and inadvertent indirect ingestion of airborne particulates deposited on the tunnel floor. The gradual removal of surface contamination over time and the ingrowth of decay products were considered in calculating the dose at different times. The maximum doses were estimated to be 1.5 mrem/yr for the recreationist and 0.34 mrem/yr for the maintenance worker

  9. Sample collection and sample analysis plan in support of the 105-C/190-C concrete and soil sampling activities

    International Nuclear Information System (INIS)

    Marske, S.G.

    1996-07-01

    This sampling and analysis plan describes the sample collection and sample analysis in support of the 105-C water tunnels and 190-C main pumphouse concrete and soil sampling activities. These analytical data will be used to identify the radiological contamination and presence of hazardous materials to support the decontamination and disposal activities

  10. 26 CFR 1.190-1 - Expenditures to remove architectural and transportation barriers to the handicapped and elderly.

    Science.gov (United States)

    2010-04-01

    ... § 1.190-2(b) of this chapter). In the case of a partnership, the election shall be made by the partnership. The election applies to expenditures paid or incurred during the taxable year which (but for the election) are chargeable to capital account. (b) Limitation. The maximum deduction for a taxpayer...

  11. Surface vertical deposition for gold nanoparticle film

    International Nuclear Information System (INIS)

    Diao, J J; Qiu, F S; Chen, G D; Reeves, M E

    2003-01-01

    In this rapid communication, we present the surface vertical deposition (SVD) method to synthesize the gold nanoparticle films. Under conditions where the surface of the gold nanoparticle suspension descends slowly by evaporation, the gold nanoparticles in the solid-liquid-gas junction of the suspension aggregate together on the substrate by the force of solid and liquid interface. When the surface properties of the substrate and colloidal nanoparticle suspension define for the SVD, the density of gold nanoparticles in the thin film made by SVD only depends on the descending velocity of the suspension surface and on the concentration of the gold nanoparticle suspension. (rapid communication)

  12. [Biosynthesis of gold nanoparticles by Azospirillum brasilense].

    Science.gov (United States)

    Kupriashina, M A; Vetchinkina, E P; Burov, A M; Ponomareva, E G; Nikitina, V E

    2014-01-01

    Plant-associated nitrogen-fixing soil bacteria Azospirillum brasilense were shown to reduce the gold of chloroauric acid to elemental gold, resulting in formation of gold nanoparicles. Extracellular phenoloxidizing enzymes (laccases and Mn peroxidases) were shown to participate in reduction of Au+3 (HAuCl4) to Au(0). Transmission electron microscopy revealed accumulation of colloidal gold nanoparticles of diverse shape in the culture liquid of A. brasilense strains Sp245 and Sp7. The size of the electron-dense nanospheres was 5 to 50 nm, and the size of nanoprisms varied from 5 to 300 nm. The tentative mechanism responsible for formation of gold nanoparticles is discussed.

  13. Gold and not so real gold in Medieval treatises

    Directory of Open Access Journals (Sweden)

    Srebrenka Bogovic-Zeskoski

    2015-01-01

    Full Text Available The aim of this study is to evidence diverse materials and processes used by artisans (and alchemists required to synthesize a visually viable replacement for gold. The emphasis of the research is upon the production of mosaic gold or porporina, a pigment that has survived into modern times, which was used as ink and as paint. Base metals, mostly tin, but also alloys were used both into foils coated with glazes and varnishes and as pigment. The research focuses upon recipes documented in treatises dating from Antiquity to the late Medieval period (ca. 1500 and an attempt is made to answer two questions. In the first place, why was there a need for a surrogate? Secondly, why are there so few tangible examples detected on surviving artifacts? In conclusion, an argument is offered pointing out that, although much can be learned by scientific examination of artifacts, textual analysis is equally important and necessary to unravel mysteries of ancient technologies

  14. Nanotoxicity of gold and gold-cobalt nanoalloy.

    Science.gov (United States)

    Girgis, E; Khalil, W K B; Emam, A N; Mohamed, M B; Rao, K V

    2012-05-21

    Nanotoxicology test of gold nanoparticles (Au NPs) and gold-cobalt (Au-Co) nanoalloy is an important step in their safety evaluation for biomedical applications. The Au and Au-Co NPs were prepared by reducing the metal ions using sodium borohydride (NaBH(4)) in the presence of polyvinyl pyrrolidone (PVP) as a capping material. The average size and shape of the nanoparticles (NPs) were characterized using high resolution transmission electron microscopy (HRTEM). Cobalt presence in the nanoalloy was confirmed by energy dispersive X-ray spectroscopy (EDX) analysis, and the magnetic properties of these particles were determined using a vibrating sample magnetometer (VSM). The Gold and gold-cobalt NPs of average size 15 ± 1.5 nm were administered orally to mice with a dose of 80, 160, and 320 mg/kg per body weight (bw) using gavages. Samples were collected after 7 and 14 days of the treatment. The results indicated that the Au-Co NPs were able to induce significant alteration in the tumor-initiating genes associated with an increase of micronuclei (MNs) formation and generation of DNA adduct (8-hydroxy-2-deoxyguanosine, 8-OHdG) as well as a reduction in the glutathione peroxidase activity. This action of Au-Co NPs was observed using 160 and 320 mg/kg bw at both time intervals. However, Au NPs had much lower effects than Au-Co NPs on alteration in the tumor-initiating genes, frequency of MNs, and generation of 8-OHdG as well as glutathione peroxidase activity except with the highest dose of Au NPs. This study suggests that the potential to cause in vivo genetic and antioxidant enzyme alterations due to the treatment by Au-Co nanoalloy may be attributed to the increase in oxidative stress in mice.

  15. Distribution and composition of gold in porphyry gold systems: example from the Biely Vrch deposit, Slovakia

    Science.gov (United States)

    Koděra, Peter; Kozák, Jaroslav; Brčeková, Jana; Chovan, Martin; Lexa, Jaroslav; Jánošík, Michal; Biroň, Adrián; Uhlík, Peter; Bakos, František

    2018-03-01

    The Biely Vrch deposit in the Western Carpathians is assigned to the shallow, sulfide-poor porphyry gold deposit type and has an exceptionally low Cu/Au ratio. According to 3-D geochemical models, there is a limited spatial correlation between Au and Cu due to the primary introduction of gold by a salt melt and Cu by low-density vapor. Despite a rough spatial correlation of gold grades with quartz stockwork intensity, gold is hosted mostly by altered rock, exclusively in native form. Three main gold mineral assemblages were recognized here. In the deepest parts of the system, the K- and Ca-Na silicate gold assemblage is associated with minerals of high-temperature alteration (plagioclase, K-feldspar, actinolite), with gold grades and fineness depending on depth and potassium content of the host rock: K-silicate alteration hosts the lowest fineness gold ( 914), whereas Ca-Na silicate alteration has the highest ( 983). The intermediate argillic gold assemblage is the most widespread, with gold hosted mainly by chlorite, illite, smectite, and interstratified illite-chlorite-smectite minerals. The gold fineness is mostly variable (875-990) and inherited from the former gold mineral assemblages. The latest advanced argillic gold assemblage has its gold mostly in kaolinite. The extremely high fineness ( 994) results from gold remobilization by late-stage aqueous magmatic-hydrothermal fluids. Uncommon bonanza-grade appears where the earlier gold mineral assemblages were further enriched by this remobilized gold. Primary precipitation of gold occurred during ascent and cooling of salt melts at 450 to 309 °C, mostly during retrograde quartz solubility.

  16. Evaluation of mercury speciation and removal through air pollution control devices of a 190 MW boiler.

    Science.gov (United States)

    Wu, Chengli; Cao, Yan; Dong, Zhongbing; Cheng, Chinmin; Li, Hanxu; Pan, Weiping

    2010-01-01

    Air pollution control devices (APCDs) are installed at coal-fired power plants for air pollutant regulation. Selective catalytic reduction (SCR) and wet flue gas desulfurization (FGD) systems have the co-benefits of air pollutant and mercury removal. Configuration and operational conditions of APCDs and mercury speciation affect mercury removal efficiently at coal-fired utilities. The Ontario Hydro Method (OHM) recommended by the U.S. Environmental Protection Agency (EPA) was used to determine mercury speciation simultaneously at five sampling locations through SCR-ESP-FGD at a 190 MW unit. Chlorine in coal had been suggested as a factor affecting the mercury speciation in flue gas; and low-chlorine coal was purported to produce less oxidized mercury (Hg2+) and more elemental mercury (Hg0) at the SCR inlet compared to higher chlorine coal. SCR could oxidize elemental mercury into oxidized mercury when SCR was in service, and oxidation efficiency reached 71.0%. Therefore, oxidized mercury removal efficiency was enhanced through a wet FGD system. In the non-ozone season, about 89.5%-96.8% of oxidized mercury was controlled, but only 54.9%-68.8% of the total mercury was captured through wet FGD. Oxidized mercury removal efficiency was 95.9%-98.0%, and there was a big difference in the total mercury removal efficiencies from 78.0% to 90.2% in the ozone season. Mercury mass balance was evaluated to validate reliability of OHM testing data, and the ratio of mercury input in the coal to mercury output at the stack was from 0.84 to 1.08.

  17. Description of identical superdeformed bands of the A ∝ 190 mass region

    International Nuclear Information System (INIS)

    Dadwal, Anshul; Mittal, H.M.

    2017-01-01

    The two-parameter formula/model viz. nuclear softness (NS) formula, semiclassical particle rotor model (PRM) and exponential model with pairing attenuation are used for the reliable phenomenological analysis of identical superdeformed bands. These formulae/models are employed to study the identical superdeformed bands of the A ∝ 190 mass region, {"1"9"1Hg(2), "1"9"3Hg(2)}, {"1"9"1Hg(3), "1"9"3Hg(3)}, {"1"9"3Tl(3), "1"9"3Tl(5)}, {"1"9"3Tl(1), "1"9"4Tl(3)}, {"1"9"3Tl(1), "1"9"4Tl(4)}, {"1"9"3Pb(3), "1"9"1Hg(2)}, {"1"9"3Pb(4), "1"9"1Hg(3)}, {"1"9"4Pb(1), "1"9"2Hg(1)}, {"1"9"4Pb(1), "1"9"4Hg(1)} and middle-point identical bands {"1"9"3Tl(1), "1"9"3Tl(2)}, {"1"9"3Tl(1), "1"9"5Tl(1)} and {"1"9"3Tl(2), "1"9"5Tl(2)}. Quantitatively, good results of γ-ray transitions energies and dynamic moment of inertia are obtained using the NS formula. The parameters, band-head moment of inertia (I_0), alignment (i) and effective pairing parameter (Δ_0) are calculated using the least-squares fitting of the γ-ray transitions energies in the NS formula, semiclassical PRM and exponential model with pairing attenuation, respectively. The calculated parameters are found to depend sensitively on the proposed band-head spin. (orig.)

  18. Description of identical superdeformed bands of the A ∝ 190 mass region

    Energy Technology Data Exchange (ETDEWEB)

    Dadwal, Anshul; Mittal, H.M. [Dr. B.R. Ambedkar National Institute of Technology, Jalandhar (India)

    2017-06-15

    The two-parameter formula/model viz. nuclear softness (NS) formula, semiclassical particle rotor model (PRM) and exponential model with pairing attenuation are used for the reliable phenomenological analysis of identical superdeformed bands. These formulae/models are employed to study the identical superdeformed bands of the A ∝ 190 mass region, {"1"9"1Hg(2), "1"9"3Hg(2)}, {"1"9"1Hg(3), "1"9"3Hg(3)}, {"1"9"3Tl(3), "1"9"3Tl(5)}, {"1"9"3Tl(1), "1"9"4Tl(3)}, {"1"9"3Tl(1), "1"9"4Tl(4)}, {"1"9"3Pb(3), "1"9"1Hg(2)}, {"1"9"3Pb(4), "1"9"1Hg(3)}, {"1"9"4Pb(1), "1"9"2Hg(1)}, {"1"9"4Pb(1), "1"9"4Hg(1)} and middle-point identical bands {"1"9"3Tl(1), "1"9"3Tl(2)}, {"1"9"3Tl(1), "1"9"5Tl(1)} and {"1"9"3Tl(2), "1"9"5Tl(2)}. Quantitatively, good results of γ-ray transitions energies and dynamic moment of inertia are obtained using the NS formula. The parameters, band-head moment of inertia (I{sub 0}), alignment (i) and effective pairing parameter (Δ{sub 0}) are calculated using the least-squares fitting of the γ-ray transitions energies in the NS formula, semiclassical PRM and exponential model with pairing attenuation, respectively. The calculated parameters are found to depend sensitively on the proposed band-head spin. (orig.)

  19. Collaborative journalism: the Twitter @plantao190 and police journalism in Curitiba

    Directory of Open Access Journals (Sweden)

    Bruno Henrique Marques de Mendonça

    2013-04-01

    Full Text Available This article aims to show how the Internet and the popularization of production tools potentialize the ability of ordinary, amateur people, to produce news, a fact previously reserved to professional journalists in lieu of service communication vehicles. Thus, ownership of technology and the eliminationof geographical barriers, provided by the Internet, helped spread the content of these amateurs, removing the, until then, absolute exclusivity of the journalist to spread facts and disclose information. For this, we carried out a bibliographic review to try and understand how this empowerment process of the amateur started and what are its effects on the practice of journalism. As a theoretical reference, it is possible to highlight authors such as: Dam Gilmor (2005, reference in engaging the topic of evolution of the practice of journalism and collaborative journalism; Francis Pisani & Dominique Piotet (2010, that have dedicated their studies to show the transformation of the web and its impacts on communication, and, finally, author Clay Shirky, who analyses the amateur productions published on the Internet and their relation with its users. As an empirical approach to exemplify the presented theory, a Twitter profile, microblogging tool on which is it possible to post texts with up to 140 characters via mobile devices with an internet connection, was selected. The profile @plantao190 is curated by photographer João Carlos Frigério, who is not a journalist (despite his title, but still informs in real time the police occurrences in the city of Curitiba, becoming a reference in the area and being read by thousands of users who, besides consuming his content, interact and even send their reports which later become new posts.

  20. Byzantine gold coins and jewellery

    International Nuclear Information System (INIS)

    Oddy, A.; La Niece, S.

    1986-01-01

    The article deals with the dating of Byzantine gold coinage. The results of such a study are of fundamental importance for the study of the economic history of the later Byzantine Empire and they are also of importance for the historian of technology when studying the composition of the contemporary Byzantine jewellery. Although Carbon-14 dating cannot be used as a method af dating, historians can still benefit from the analysis of the alloy of which the antiquity is made, as this is sometimes characteristic of the period in which it was used. A number of pieces of Byzantine jewellery has been analysed by x-ray fluorescence analysis, after first gently abrading a small area of the surface of the gold with the carborundum paper in an inconspicious position on the back or side of the object. A table is given on the results of this analysis

  1. Reverse Transfection Using Gold Nanoparticles

    Science.gov (United States)

    Yamada, Shigeru; Fujita, Satoshi; Uchimura, Eiichiro; Miyake, Masato; Miyake, Jun

    Reverse transfection from a solid surface has the potential to deliver genes into various types of cell and tissue more effectively than conventional methods of transfection. We present a method for reverse transfection using a gold colloid (GC) as a nanoscaffold by generating nanoclusters of the DNA/reagentcomplex on a glass surface, which could then be used for the regulation of the particle size of the complex and delivery of DNA into nuclei. With this method, we have found that the conjugation of gold nanoparticles (20 nm in particle size) to the pEGFP-N1/Jet-PEI complex resulted in an increase in the intensity of fluorescence of enhanced green fluorescent protein (EGFP) (based on the efficiency of transfection) from human mesenchymal stem cells (hMSCs), as compared with the control without GC. In this manner, we constructed a method for reverse transfection using GC to deliver genes into the cells effectively.

  2. CMS Industries awarded gold, crystal

    CERN Multimedia

    2006-01-01

    The CMS collaboration honoured 10 of its top suppliers in the seventh annual awards ceremony The representatives of the firms that recieved the CMS Gold and Crystal Awards stand with their awards after the ceremony. The seventh annual CMS Awards ceremony was held on Monday 13 March to recognize the industries that have made substantial contributions to the construction of the collaboration's detector. Nine international firms received Gold Awards, and General Tecnica of Italy received the prestigious Crystal Award. Representatives from the companies attended the ceremony during the plenary session of CMS week. 'The role of CERN, its machines and experiments, beyond particle physics is to push the development of equipment technologies related to high-energy physics,'said CMS Awards Coordinator Domenico Campi. 'All of these industries must go beyond the technologies that are currently available.' Without the involvement of good companies over the years, the construction of the CMS detector wouldn't be possible...

  3. Nanobubble trouble on gold surfaces

    DEFF Research Database (Denmark)

    Holmberg, Maria; Kuhle, A.; Garnaes, J.

    2003-01-01

    When analyzing surfaces related to biosensors with in situ atomic force microscopy (AFM), the existence of nanobubbles called for our attention. The bubbles seem to form spontaneously when gold surfaces are immersed in clean water and are probably a general phenomenon at water-solid interfaces....... Besides from giving rise to undesired effects in, for example, biosensors, nanobubbles can also cause artifacts in AFM imaging. We have observed nanobubbles on unmodified gold surfaces, immersed in clean water, using standard silicon AFM probes. Nanobubbles can be made to disappear from contact mode AFM...... images and then to reappear by changing the scanning force. By combining contact mode AFM imaging and local force measurements, the interaction between the nanobubbles and the probe can be analyzed and give information about the characteristics of nanobubbles. A model of the forces between the AFM probe...

  4. Gold, currencies and market efficiency

    Czech Academy of Sciences Publication Activity Database

    Krištoufek, Ladislav; Vošvrda, Miloslav

    2016-01-01

    Roč. 449, č. 1 (2016), s. 27-34 ISSN 0378-4371 R&D Projects: GA ČR(CZ) GBP402/12/G097 Institutional support: RVO:67985556 Keywords : Efficient market hypothesis, * Gold * Currencies, * Fractal dimension * Entropy * Long-Term memory Subject RIV: AH - Economics Impact factor: 2.243, year: 2016 http://library.utia.cas.cz/separaty/2016/E/kristoufek-0455876.pdf

  5. Ground Optical Lightning Detector (GOLD)

    Science.gov (United States)

    Jackson, John, Jr.; Simmons, David

    A photometer developed to characterize lightning from the ground is discussed. The detector and the electronic signal processing and data storage systems are presented along with field data measured by the system. The discussion will include improvements that will be incorporated to enhance the measurement of lightning and the data storage capability to record for many days without human involvement. Finally, the calibration of the GOLD system is presented.

  6. Extinction Coefficient of Gold Nanostars

    OpenAIRE

    de Puig, Helena; Tam, Justina O.; Yen, Chun-Wan; Gehrke, Lee; Hamad-Schifferli, Kimberly

    2015-01-01

    Gold nanostars (NStars) are highly attractive for biological applications due to their surface chemistry, facile synthesis and optical properties. Here, we synthesize NStars in HEPES buffer at different HEPES/Au ratios, producing NStars of different sizes and shapes, and therefore varying optical properties. We measure the extinction coefficient of the synthesized NStars at their maximum surface plasmon resonances (SPR), which range from 5.7 × 108 to 26.8 × 108 M−1cm−1. Measured values correl...

  7. Biomolecular Assembly of Gold Nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Micheel, Christine Marya [Univ. of California, Berkeley, CA (United States)

    2005-05-20

    Over the past ten years, methods have been developed to construct discrete nanostructures using nanocrystals and biomolecules. While these frequently consist of gold nanocrystals and DNA, semiconductor nanocrystals as well as antibodies and enzymes have also been used. One example of discrete nanostructures is dimers of gold nanocrystals linked together with complementary DNA. This type of nanostructure is also known as a nanocrystal molecule. Discrete nanostructures of this kind have a number of potential applications, from highly parallel self-assembly of electronics components and rapid read-out of DNA computations to biological imaging and a variety of bioassays. My research focused in three main areas. The first area, the refinement of electrophoresis as a purification and characterization method, included application of agarose gel electrophoresis to the purification of discrete gold nanocrystal/DNA conjugates and nanocrystal molecules, as well as development of a more detailed understanding of the hydrodynamic behavior of these materials in gels. The second area, the development of methods for quantitative analysis of transmission electron microscope data, used computer programs written to find pair correlations as well as higher order correlations. With these programs, it is possible to reliably locate and measure nanocrystal molecules in TEM images. The final area of research explored the use of DNA ligase in the formation of nanocrystal molecules. Synthesis of dimers of gold particles linked with a single strand of DNA possible through the use of DNA ligase opens the possibility for amplification of nanostructures in a manner similar to polymerase chain reaction. These three areas are discussed in the context of the work in the Alivisatos group, as well as the field as a whole.

  8. Gold Nanocages for Biomedical Applications**

    OpenAIRE

    Skrabalak, Sara E.; Chen, Jingyi; Au, Leslie; Lu, Xianmao; Li, Xingde; Xia, Younan

    2007-01-01

    Nanostructured materials provide a promising platform for early cancer detection and treatment. Here we highlight recent advances in the synthesis and use of Au nanocages for such biomedical applications. Gold nanocages represent a novel class of nanostructures, which can be prepared via a remarkably simple route based on the galvanic replacement reaction between Ag nanocubes and HAuCl4. The Au nanocages have a tunable surface plasmon resonance peak that extends into the near-infrared, where ...

  9. Jabiluka gold-uranium project

    International Nuclear Information System (INIS)

    1988-01-01

    The Jabiluka gold-uranium deposit, 230km east of Darwin in the Alligator Rivers Region of the Northern Territory, was discovered by Pancontinental Mining Limited in 1971. Jabiluka, with reserves in excess of 200,000 tonnes of contained U 3 O 8 in two deposits 500 metres apart, is the world's largest high grade uranium deposit and also contains nearly 12 tonnes of gold. It is proposed that only the larger deposit, Jabiluka II will be mined - by underground extraction methods, and that 275,000 tonnes of ore per year will be mined and processed to produce 1,500 tonnes of U 3 O 8 and up to 30,000 oz of gold. The revenue from the uranium sales is estimated to be of the order of A$100 million per year at A$30/lb. By the end of 1982 all necessary mining and environmental approvals had been obtained and significant marketing progress made. With the Australian Labor Party winning Commonwealth Government in the 1983 election, Pancontinental's permission to seek sales contracts was withdrawn and development of the Jabiluka deposit ceased. Jabiluka remains undeveloped - awaiting a change in Australian Government policy on uranium. figs., maps

  10. Analysis of gold and silver concentration on gold mining tailings by neutron activation analysis

    International Nuclear Information System (INIS)

    Sadikov, I.I.; Salimov, M.I.; Sadykova, Z.O.

    2014-01-01

    Full text: Instrumental neutron-activation analysis without radiochemical separation is one of most applicable and often used methods to analyze the concentration of gold, silver and other rare and noble metals in gold ores. This method is not suitable for analyzing low concentration of gold and silver in gold mining tailings due to rather high concentration of some elements. Samples are dissolved by boiling in a mixture of concentrated hydrochloric and nitric acids to extract gold and silver into the solution. Chemical yield of gold and silver after dissolution of the sample and further chromatographic separation is between 92 and 95 percent respectively

  11. Draft Genome Sequence of the Phosphate-Solubilizing Bacterium Pseudomonas argentinensis Strain SA190 Isolated from the Desert Plant Indigofera argentea

    KAUST Repository

    Lafi, Feras Fawzi

    2016-12-23

    Pseudomonas argentinensis strain SA190 is a plant endophytic-inhabiting bacterium that was isolated from root nodules of the desert plant Indigofera argentea collected from the Jizan region of Saudi Arabia. Here, we report the genome sequence of SA190, highlighting several functional genes related to plant growth-promoting activity, environment adaption, and antifungal activity.

  12. Joint Oil Analysis Program Spectrometer Standards SCP Science (Conostan) Qualification Report for D19-0, D3-100, and D12-XXX Series Standards

    Science.gov (United States)

    2015-05-20

    Joint Oil Analysis Program Spectrometer Standards SCP Science (Conostan) Qualification Report For D19-0, D3-100, and D12- XXX Series Standards NF...Candidate Type D19-0 ICP-AES Results ..................................................................... 4 Table V. Candidate Type D12- XXX ...Physical Property Results .................................................. 5 Table VI. Candidate Type D12- XXX Rotrode-AES Results

  13. Recovery of carrier-free gold-195

    International Nuclear Information System (INIS)

    Iofa, B.Z.; Ivanova, N.A.

    1995-01-01

    It is known that gold(III) is readily extracted from nitric acid solutions with ethers. The authors have studied extraction of trace amounts of gold(III) from nitric acid solutions with diethyl and diisopropyl ethers in the presence of significant excess of Pt(IV). Distribution coefficients of gold(III) were measured radiometrically using carrier-free gold-195 or spectrophotometrically in the presence of platinum(IV). Very high coefficients of gold separation from platinum may be achieved. Preliminary experiments have shown that zinc-65 was not extracted with ethers from nitric acid solutions. As an extraction system, the authors have chosen the system 10 M HNO 3 -diisopropyl ether. After model experiments, the authors have performed recovery of carrier-free gold-195 from a real platinum target irradiated with protons in a cyclotron

  14. Linear Optical Properties of Gold Colloid

    Directory of Open Access Journals (Sweden)

    Jingmin XIA

    2015-11-01

    Full Text Available Gold colloid was prepared by reducing HAuCl4·4H2O with Na3C6H5O7·2H2O. The morphology, size of gold nanoparticles and the optical property of colloid were characterized by transmission electron microscope and UV-Vis spectrophotometer, respectively. It shows that the gold nanoparticles are in the shape of spheres with diameters less than 8 nm, and the surface plasmon resonance absorption peak is located at about 438 nm. As the volume fraction of gold particles increases, the intensity of absorption peak strengthens. The optical property of gold colloid was analyzed by Maxwell-Garnett (MG effective medium theory in the company of Drude dispersion model. The results show that the matrix dielectric constant is a main factor, which influences the optical property of gold colloid.DOI: http://dx.doi.org/10.5755/j01.ms.21.4.9558

  15. Physiological investigation of gold nanorods toward watermelon.

    Science.gov (United States)

    Wan, Yujie; Li, Junli; Ren, Hongxuan; Huang, Jin; Yuan, Hong

    2014-08-01

    The objective of the present study was to evaluate the phytotoxicity and oxidant stress of the gold nanorods toward watermelon, and hence give a quantitative risk assessment of both seeds and plants phase. The seed germination, the activity of antioxidant enzymes, and the contents of soluble protein and malondialdehyde (MDA) have been measured while the plant roots were observed by transmission electron microscopy (TEM). It was found that the gold nanorods significantly promoted the root elongation. Furthermore, the results on the enzymes activities of plant indicated that oxidative stress happened in the plant treated with gold nanorods. However, the gold nanorods resulted in the phytotoxicity toward plant especially at high concentration. The TEM images of the plant roots with and without the treatment of gold nanorods showed the significant different size of starch granules. In conclusion, significant physiological changes of plant occurred after treatment with the gold nanorods.

  16. Single meson production in proton diffraction at 190 GeV/c at COMPASS

    International Nuclear Information System (INIS)

    Weisrock, Tobias

    2015-01-01

    The quark model successfully describes all ground state baryons as members of SU(N) flavour multiplets. For excited baryon states the situation is totally different. There are much less states found in the experiment than predicted in most theoretical calculations. This fact has been known for a long time as the 'missing resonance problem'. In addition, many states found in experiments are only poorly measured up to now. Therefore, further experimental efforts are needed to clarify the situation. At COMPASS, reactions of a 190 GeV/c hadron beam impinging on a liquid hydrogen target are investigated. The hadron beam contains different species of particles (π,K,p). To distinguish these particles, two Cherenkov detectors are used. In this thesis, a new method for the identification of particles from the detector information is developed. This method is based on statistical approaches and allows a better kaon identification efficiency with a similar purity compared to the method, which was used before. The reaction pp→ppX with X=(π 0 ,η,ω,φ) is used to study different production mechanisms. A previous analysis of ω and φ mesons is extended to pseudoscalar mesons. As the resonance contributions in pη are smaller than in pπ 0 a different behaviour of these two final states is expected as a function of kinematic variables. The investigation of these differences allows to study different production mechanisms and to estimate the size of the resonant contribution in the different channels. In addition, the channel pp→ppX allows to study baryon resonances in the pX system. In the COMPASS energy regime, the reaction is dominated by Pomeron exchange. As a Pomeron carries vacuum quantum numbers, no isospin is transferred between the target proton and the beam proton. Therefore, the pX final state has isospin (1)/(2) and all baryon resonances in this channel are N* baryons. This offers the opportunity to do spectroscopy without taking Δ resonances into

  17. New results on lepton flavour violation in collisions at 190 - 210 GeV and their cosmological interest

    International Nuclear Information System (INIS)

    Laurian, Ion Mihai; Angelescu, T.; Lazanu, I.; Mihul, A.; Malace, S.; Haiduc, M.; Biasini, Maurizio; Santinelli, R.; Pioppi, M.

    2002-01-01

    The conservation of lepton number separately for each generation has no strong theoretical basis. LEP experiments have investigated the channels in the Z mass region and obtained a limit of about 95% confidence level. First results have been published by L3 Collaboration in 1993. New data at energies between 190 and 210 GeV have been obtained. These data have been analysed in order to search for events violating lepton flavour number in this energy range. (authors)

  18. Deep inelastic reactions and isomers in neutron-rich nuclei across the perimeter of the A = 180 - 190 deformed region

    International Nuclear Information System (INIS)

    Dracoulis, G.D.; Lane, G.J.; Byrne, A.P.; Watanabe, H.; Hughes, R.O.; Kondev, F.G.; Carpenter, M.P.; Janssens, R.V.F.; Lauritsen, T.; Lister, C.J.; Seweryniak, D.; Zhu, S.; Chowdhury, P.; Shi, Y.; Xu, F.R.

    2014-01-01

    Recent results on high-spin isomers populated in deep-inelastic reactions in the transitional tungsten-osmium region are outlined with a focus on 190 Os, 192 Os and 194 Os. As well as the characterization of several two-quasineutron isomers, the 12 + and 20 + isomers in 192 Os are interpreted as manifestations of maximal rotation alignment within the neutron i(13/2) and possibly proton h(11/2) shells at oblate deformation. (authors)

  19. Gold and Silver Extraction from Leach Solutions

    Directory of Open Access Journals (Sweden)

    Bagdaulet K. Kenzhaliyev

    2014-03-01

    Full Text Available There has been carried out an investigation on the extraction of gold and silver from thiosulfate solutions: standard test and technological solutions of chemical and electrochemical leaching. The influence of related metals on the process of extracting gold from solution was studied. There has been conducted a comparative study of the IR spectra of solutions after the sorption of gold, silver and related metals.

  20. Geochemical indicators of gold ore fields

    International Nuclear Information System (INIS)

    Shcherbakov, Yu.G.

    1995-01-01

    The principles of selection of indicators for genetic reconstructions and prognostic valuations of gold mineralization of diverse morphological and geochemical types have been substantiated. The neutron-activation analysis with radiochemical separation and detection limit of 1-10 -8 %, instrumental neutron-activation analysis and atomic-absorption analysis are the main methods of determination of gold low contents in the rocks, as well as diverse elements, including transition, rare earth elements and tellurium, in gold. 50 refs.; 1 fig.; 3 tabs

  1. Glyco-gold nanoparticles: synthesis and applications

    OpenAIRE

    Compostella, Federica; Pitirollo, Olimpia; Silvestri, Alessandro; Polito, Laura

    2017-01-01

    Glyco-gold nanoparticles combine in a single entity the peculiar properties of gold nanoparticles with the biological activity of carbohydrates. The result is an exciting nanosystem, able to mimic the natural multivalent presentation of saccharide moieties and to exploit the peculiar optical properties of the metallic core. In this review, we present recent advances on glyco-gold nanoparticle applications in different biological fields, highlighting the key parameters which inspire the glyco ...

  2. Glyco-gold nanoparticles: synthesis and applications

    Directory of Open Access Journals (Sweden)

    Federica Compostella

    2017-05-01

    Full Text Available Glyco-gold nanoparticles combine in a single entity the peculiar properties of gold nanoparticles with the biological activity of carbohydrates. The result is an exciting nanosystem, able to mimic the natural multivalent presentation of saccharide moieties and to exploit the peculiar optical properties of the metallic core. In this review, we present recent advances on glyco-gold nanoparticle applications in different biological fields, highlighting the key parameters which inspire the glyco nanoparticle design.

  3. Coal gold agglomeration: an innovative approach to the recovery of gold in environmentally sensitive areas

    Energy Technology Data Exchange (ETDEWEB)

    Wall, N.C.; Hughes-Narborough, C.; Willey, G. [Davy (Stockton) Ltd., Stockton-on-Tees (United Kingdom)

    1994-11-01

    Coal Gold Agglomeration (CGA) was developed by BP Minerals and involves the selective recovery of oleophilic gold particles from an aqueous slurry into coal-oil agglomerates. These agglomerates are allowed to build up to a high gold loading and are then separated from the slurry. The loaded agglomerates are burned and the gold is finally recovered from the ash residue by dissolution and precipitation or by direct smelting. 6 figs.

  4. Gold nano-particles fixed on glass

    International Nuclear Information System (INIS)

    Worsch, Christian; Wisniewski, Wolfgang; Kracker, Michael; Rüssel, Christian

    2012-01-01

    Highlights: ► We produced wear resistant gold–ruby coatings on amorphous substrates. ► Thin sputtered gold layers were covered by or embedded in silica coatings. ► Annealing above T g of the substrate glass led to the formation of gold nano particles. ► A 1 1 1-texture of the gold particles is observed via XRD and EBSD. ► EBSD-patterns can be acquired from crystals covered by a thin layer of glass. - Abstract: A simple process for producing wear resistant gold nano-particle coatings on transparent substrates is proposed. Soda-lime-silica glasses were sputtered with gold and subsequently coated with SiO 2 using a combustion chemical vapor deposition technique. Some samples were first coated with silica, sputtered with gold and then coated with a second layer of silica. The samples were annealed for 20 min at either 550 or 600 °C. This resulted in the formation of round, well separated gold nano-particles with sizes from 15 to 200 nm. The color of the coated glass was equivalent to that of gold–ruby glasses. Silica/gold/silica coatings annealed at 600 °C for 20 min were strongly adherent and scratch resistant. X-ray diffraction and electron backscatter diffraction (EBSD) were used to describe the crystal orientations of the embedded particles. The gold particles are preferably oriented with their (1 1 1) planes perpendicular to the surface.

  5. CO oxidation on gold nanoparticles: Theoretical studies

    DEFF Research Database (Denmark)

    Remediakis, Ioannis; Lopez, Nuria; Nørskov, Jens Kehlet

    2005-01-01

    We present a summary of our theoretical results regarding CO oxidation on both oxide-supported and isolated gold nanoparticles. Using Density Functional Theory we have studied the adsorption of molecules and the oxidation reaction of CO on gold clusters. Low-coordinated sites on the gold...... nanoparticles can adsorb small inorganic molecules such as O2 and CO, and the presence of these sites is the key factor for the catalytic properties of supported gold nanoclusters. Other contributions, induced by the presence of the support, can provide parallel channels for the reaction and modulate the final...

  6. Gold Rushes and mineral property rights allocation

    DEFF Research Database (Denmark)

    Sinding, Knud

    , is to handle the other projects that are generated by the "gold rush" informational externalities created by the initial discovery. At the core of the problems of dealing with a gold rush situation is both the informational externality and an institutional framework which is not designed to deal with large...... influxes of prospectors competing for a very limited area. This paper charts significant gold rush events in the mineral industry in recent decades and uses preliminary data on the areas impacted by these gold rushes to argue that many mineral tenure systems should be modified in order to be better able...

  7. Nuclear excitation in muonic gold

    CERN Document Server

    Robert Tissot, B; Debrunner, P; Engfer, R; Link, R; Schellenberg, L; Schneuwly, H; Walter, H K

    1973-01-01

    Energies and intensities of muonic X-rays in gold were measured at the CERN muon channel with an experimental set-up as described by Backe et al. (1972). The 2p-1s and 3d-2p transitions could only be analysed taking into account beside the static quadrupole interaction a dynamical hyperfine interaction of the 2p states, which leads to an excitation of the first four nuclear levels. The dynamical hyperfine interaction was calculated using the core excitation model (de Shalit, (1961)). (0 refs).

  8. The Resonance Integral of Gold

    Energy Technology Data Exchange (ETDEWEB)

    Jirlow, K; Johansson, E

    1959-04-15

    The resonance activation integral of gold has been determined, by means of cadmium ratio measurements of thin foils in a neutron beam. Comparison was made with a 1/v detector, and the neutron spectra were measured with a chopper. The resonance integral, RI, is defined as {integral}{sub 0.5}{sup {infinity}}{sigma}{sub r}(E)dE/E, where {sigma}{sub r}(E) is the differenc between the total absorption cross section and the 1/v part. An experimental value of 1490 {+-} 40 barns has been obtained. RI has also been computed from resonance parameter data with the result 1529 {+-} 70 barns.

  9. Gold nanoparticles covalently assembled onto vesicle structures as possible biosensing platform

    Directory of Open Access Journals (Sweden)

    M. Fátima Barroso

    2016-05-01

    Full Text Available In this contribution a strategy is shown to covalently immobilize gold nanoparticles (AuNPs onto vesicle bilayers with the aim of using this nanomaterial as platform for the future design of immunosensors. A novel methodology for the self-assembly of AuNPs onto large unilamellar vesicle structures is described. The vesicles were formed with 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC and 1-undecanethiol (SH. After, the AuNPs photochemically synthesized in pure glycerol were mixed and anchored onto SH–DOPC vesicles. The data provided by voltammetry, spectrometry and microscopy techniques indicated that the AuNPs were successfully covalently anchored onto the vesicle bilayer and decorated vesicles exhibit a spherical shape with a size of 190 ± 10 nm. The developed procedure is easy, rapid and reproducible to start designing a possible immunosensor by using environmentally friendly procedures.

  10. Geochemical methodology for gold prospect ion in Uruguay

    International Nuclear Information System (INIS)

    Spangenber, J.

    1987-01-01

    This work is about the history of gold prospection in Uruguay. In this study there are considered the geochemical aspects, the gold performance, the applicability to mining prospection and the gold prospection aluvionar

  11. Gold emissivities for hydrocode applications

    Science.gov (United States)

    Bowen, C.; Wagon, F.; Galmiche, D.; Loiseau, P.; Dattolo, E.; Babonneau, D.

    2004-10-01

    The Radiom model [M. Busquet, Phys Fluids B 5, 4191 (1993)] is designed to provide a radiative-hydrodynamic code with non-local thermodynamic equilibrium (non-LTE) data efficiently by using LTE tables. Comparison with benchmark data [M. Klapisch and A. Bar-Shalom, J. Quant. Spectrosc. Radiat. Transf. 58, 687 (1997)] has shown Radiom to be inaccurate far from LTE and for heavy ions. In particular, the emissivity was found to be strongly underestimated. A recent algorithm, Gondor [C. Bowen and P. Kaiser, J. Quant. Spectrosc. Radiat. Transf. 81, 85 (2003)], was introduced to improve the gold non-LTE ionization and corresponding opacity. It relies on fitting the collisional ionization rate to reproduce benchmark data given by the Averroès superconfiguration code [O. Peyrusse, J. Phys. B 33, 4303 (2000)]. Gondor is extended here to gold emissivity calculations, with two simple modifications of the two-level atom line source function used by Radiom: (a) a larger collisional excitation rate and (b) the addition of a Planckian source term, fitted to spectrally integrated Averroès emissivity data. This approach improves the agreement between experiments and hydrodynamic simulations.

  12. Gold emissivities for hydrocode applications

    International Nuclear Information System (INIS)

    Bowen, C.; Wagon, F.; Galmiche, D.; Loiseau, P.; Dattolo, E.; Babonneau, D.

    2004-01-01

    The Radiom model [M. Busquet, Phys Fluids B 5, 4191 (1993)] is designed to provide a radiative-hydrodynamic code with non-local thermodynamic equilibrium (non-LTE) data efficiently by using LTE tables. Comparison with benchmark data [M. Klapisch and A. Bar-Shalom, J. Quant. Spectrosc. Radiat. Transf. 58, 687 (1997)] has shown Radiom to be inaccurate far from LTE and for heavy ions. In particular, the emissivity was found to be strongly underestimated. A recent algorithm, Gondor [C. Bowen and P. Kaiser, J. Quant. Spectrosc. Radiat. Transf. 81, 85 (2003)], was introduced to improve the gold non-LTE ionization and corresponding opacity. It relies on fitting the collisional ionization rate to reproduce benchmark data given by the Averroes superconfiguration code [O. Peyrusse, J. Phys. B 33, 4303 (2000)]. Gondor is extended here to gold emissivity calculations, with two simple modifications of the two-level atom line source function used by Radiom: (a) a larger collisional excitation rate and (b) the addition of a Planckian source term, fitted to spectrally integrated Averroes emissivity data. This approach improves the agreement between experiments and hydrodynamic simulations

  13. Paper Money but a Gold Debt. Italy in the Gold Standard

    OpenAIRE

    Giuseppe Tattara; or consequences)

    2002-01-01

    During the 52 years between the Unification of the Kingdom of Italy and World War 1, the lira was legally convertible into metal for a limited period of time. Although not formally committed to gold, the lira exchange towards the gold standard countries proved remarkably stable, \\223shadowing\\224 gold. It is widely claimed that being one of the successful members of the gold standard circle entailed a number of advantages. If the lira was closely linked to gold, suggesting that there was only...

  14. Spherical aggregates composed of gold nanoparticles

    International Nuclear Information System (INIS)

    Chen, C-C; Kuo, P-L; Cheng, Y-C

    2009-01-01

    Alkylated triethylenetetramine (C12E3) was synthesized and used as both a reductant in the preparation of gold nanoparticles by the reduction of HAuCl 4 and a stabilizer in the subsequent self-assembly of the gold nanoparticles. In acidic aqueous solution, spherical aggregates (with a diameter of about 202 ± 22 nm) of gold nanoparticles (with the mean diameter of ∼18.7 nm) were formed. The anion-induced ammonium adsorption of the alkylated amines on the gold nanoparticles was considered to provide the electrostatic repulsion and steric hindrance between the gold nanoparticles, which constituted the barrier that prevented the individual particles from coagulating. However, as the amino groups became deprotonated with increasing pH, the ammonium adsorption was weakened, and the amino groups were desorbed from the gold surface, resulting in discrete gold particles. The results indicate that the morphology of the reduced gold nanoparticles is controllable through pH-'tunable' aggregation under the mediation of the amino groups of alkylated amine to create spherical microstructures.

  15. Gold deposits of the southern Piedmont

    Science.gov (United States)

    Pardee, J.T.; Park, C.F.

    1948-01-01

    This report deals chiefly with the gold mines in the Southern Appalachian gold belt whose workings were accessible at the time of examination, but it also · summarizes available information concerning many mines that were not accessible. Most of the mines lie within a belt, 10 to 100 miles wide, that extends

  16. Nonlinear optical studies of single gold nanoparticles

    NARCIS (Netherlands)

    Dijk, Meindert Alexander van

    2007-01-01

    Gold nanoparticles are spherical clusters of gold atoms, with diameters typically between 1 and 100 nanometers. The applications of these particles are rather diverse, from optical labels for biological experiments to data carrier for optical data storage. The goal of my project was to develop new

  17. Ionization model for nickel-like gold

    International Nuclear Information System (INIS)

    Busquet, M.; Bruneau, J.

    1986-04-01

    Before we build an extensive population model for gold ionized 49 to 52 times, we have studied with a more simple model the effect of accounting for cascades (or dielectronic recombination) and Δn = 0 transitions. These transitions allow some understanding of typical feature of experimental gold spectra

  18. The Stability of Supported Gold Catalysts

    NARCIS (Netherlands)

    Masoud, Nazila

    2018-01-01

    Gold has supreme cultural and financial value and, in form of nanoparticles smaller than 10 nm, is a unique catalyst for different industrially relevant reactions. Intriguing properties of the gold catalysts have spurred demand in the chemical industry for Au catalysts, the application of which

  19. Goudafzettingen in Suriname (Gold deposits in Surinam)

    NARCIS (Netherlands)

    Brinck, J.W.

    1956-01-01

    THE GOLD DEPOSITS IN SURINAM AND THE DISTRIBUTION OF CONCESSIONS THROUGH THE COUNTRY The fieldwork on the occurrence of primary and secondary gold deposits in Surinam on which this thesis is based was carried out by order of the Welfare Fund Surinam (Welvaarts Fonds Suriname) during the periods

  20. Gold - Old Drug with New Potentials.

    Science.gov (United States)

    Faa, Gavino; Gerosa, Clara; Fanni, Daniela; Lachowicz, Joanna I; Nurchi, Valeria M

    2018-01-01

    Research into gold-based drugs for a range of human diseases has seen a revival in recent years. This article reviews the most important applications of gold products in different fields of human pathology. Au(I) and Au(III) compounds have been re-introduced in clinical practice for targeting the cellular components involved in the onset and progression of viral and parasitic diseases, rheumatoid arthritis and cancer. After some brief historical notes, this article takes into account the applications of gold compounds against Mycobacterium tuberculosis, and also in tuberculosis and in rheumatoid arthritis treatment. The use of gold containing drugs in the cure of cancer are then considered, with special emphasis to the use of nanoparticles and to the photo-thermal cancer therapy. The use of colloidal gold in diagnostics, introduced in the last decade is widely discussed. As a last point a survey on the adverse effects and on the toxicity of the various gold derivatives in use in medicine is presented. In this review, we described the surprisingly broad spectrum of possible uses of gold in diagnostics and in therapeutic approaches to multiple human diseases, ranging from degenerative to infectious diseases, and to cancer. In particular, gold nanoparticles appear as attractive elements in modern clinical medicine, combining high therapeutic properties, high selectivity in targeting cancer cells and low toxicity. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  1. Numerical simulations of nanostructured gold films

    DEFF Research Database (Denmark)

    Repän, Taavi; Frydendahl, Christian; Novikov, Sergey M.

    2017-01-01

    We present an approach to analyse near-field effects on nanostructured gold films by finite element simulations. The studied samples are formed by fabricating gold films near the percolation threshold and then applying laser damage. Resulting samples have complicated structures, which...

  2. Gold 100: proceedings of the international conference on gold. V. 2

    International Nuclear Information System (INIS)

    Fivaz, C.E.; King, R.P.

    1986-01-01

    The proceedings of Gold 100 have been published in three separate volumes. The first deals with the mining of gold, the second with the extractive metallurgy of gold, and the third with industrial uses of gold. In this second volume, the papers on extractive metallurgy presented at the Conference reflect most of the problems that are currently of significant technical interest to the industry. This volume is divided in six main parts covering plant design, carbon-in-pulp technology, refractory gold, new technology, grinding and concentration, and leaching. The part on new technology includes papers on x-ray fluorescence analyzers, Moessbauer spectroscopy and leaching processes for uranium, while the part on grinding and concentration includes papers on nuclear and radiotracer techniques for the recovery of gold as well as various flotation parameters in the flotation behaviour of gold and uranium

  3. Gold analysis by the gamma absorption technique

    International Nuclear Information System (INIS)

    Kurtoglu, Arzu; Tugrul, A.B.

    2003-01-01

    Gold (Au) analyses are generally performed using destructive techniques. In this study, the Gamma Absorption Technique has been employed for gold analysis. A series of different gold alloys of known gold content were analysed and a calibration curve was obtained. This curve was then used for the analysis of unknown samples. Gold analyses can be made non-destructively, easily and quickly by the gamma absorption technique. The mass attenuation coefficients of the alloys were measured around the K-shell absorption edge of Au. Theoretical mass attenuation coefficient values were obtained using the WinXCom program and comparison of the experimental results with the theoretical values showed generally good and acceptable agreement

  4. Synthesis of camptothecin-loaded gold nanomaterials

    International Nuclear Information System (INIS)

    Xing Zhimin; Liu Zhiguo; Zu Yuangang; Fu Yujie; Zhao Chunjian; Zhao Xiuhua; Meng Ronghua; Tan Shengnan

    2010-01-01

    Camptothecin-loaded gold nanomaterials have been synthesized by the sodium borohydride reduction method under a strong basic condition. The obtained gold nanomaterials have been characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM) and UV-vis absorption spectroscopy. The camptothecin-loaded gold colloidal solution was very stable and can be stored for more than two months at room temperature without obvious changes. The color of the colloidal solution can change from wine red to purple and blue during the acidifying process. It was revealed that the release of camptothecin and the aggregation of gold nanoparticles can be controlled by tuning the solution pH. The present study implied that the gold nanomaterials can be used as the potential carrier for CPT delivery.

  5. Hydrofluorination of Alkynes Catalysed by Gold Bifluorides.

    Science.gov (United States)

    Nahra, Fady; Patrick, Scott R; Bello, Davide; Brill, Marcel; Obled, Alan; Cordes, David B; Slawin, Alexandra M Z; O'Hagan, David; Nolan, Steven P

    2015-01-01

    We report the synthesis of nine new N -heterocyclic carbene gold bifluoride complexes starting from the corresponding N -heterocyclic carbene gold hydroxides. A new methodology to access N,N' -bis(2,6-diisopropylphenyl)imidazol-2-ylidene gold(I) fluoride starting from N,N' -bis(2,6-diisopropylphenyl)imidazol-2-ylidene gold(I) hydroxide and readily available potassium bifluoride is also reported. These gold bifluorides were shown to be efficient catalysts in the hydrofluorination of symmetrical and unsymmetrical alkynes, thus affording fluorinated stilbene analogues and fluorovinyl thioethers in good to excellent yields with high stereo- and regioselectivity. The method is exploited further to access a fluorinated combretastatin analogue selectively in two steps starting from commercially available reagents.

  6. Synthesis of camptothecin-loaded gold nanomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Xing Zhimin [Key Laboratory of Forest Plant Ecology of Ministry of Education, Northeast Forestry University, Harbin 150040 (China); Engineering Research Center of Forest Bio-preparation, Ministry of Education, Northeast Forestry University, Harbin 150040 (China); Liu Zhiguo, E-mail: zguoliu@yahoo.com.cn [Key Laboratory of Forest Plant Ecology of Ministry of Education, Northeast Forestry University, Harbin 150040 (China); Engineering Research Center of Forest Bio-preparation, Ministry of Education, Northeast Forestry University, Harbin 150040 (China); Zu Yuangang, E-mail: nefunano@yahoo.com.cn [Key Laboratory of Forest Plant Ecology of Ministry of Education, Northeast Forestry University, Harbin 150040 (China); Engineering Research Center of Forest Bio-preparation, Ministry of Education, Northeast Forestry University, Harbin 150040 (China); Fu Yujie; Zhao Chunjian; Zhao Xiuhua; Meng Ronghua; Tan Shengnan [Key Laboratory of Forest Plant Ecology of Ministry of Education, Northeast Forestry University, Harbin 150040 (China); Engineering Research Center of Forest Bio-preparation, Ministry of Education, Northeast Forestry University, Harbin 150040 (China)

    2010-04-01

    Camptothecin-loaded gold nanomaterials have been synthesized by the sodium borohydride reduction method under a strong basic condition. The obtained gold nanomaterials have been characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM) and UV-vis absorption spectroscopy. The camptothecin-loaded gold colloidal solution was very stable and can be stored for more than two months at room temperature without obvious changes. The color of the colloidal solution can change from wine red to purple and blue during the acidifying process. It was revealed that the release of camptothecin and the aggregation of gold nanoparticles can be controlled by tuning the solution pH. The present study implied that the gold nanomaterials can be used as the potential carrier for CPT delivery.

  7. Carbonate hosted gold deposit in Tasmania, Australia

    International Nuclear Information System (INIS)

    Abadi, M.H.

    1999-01-01

    Full text: This study uses elemental and isotopic composition of carbonates associated with gold from Henty and Beaconsfield in Tasmania, Australia, to illustrate source of gold-bearing fluids, salinity, temperature and dissolution and reprecipitation of carbonate. The Beaconsfield and Henty gold mines are located in northern and western Tasmania respectively. Gold mineralisation in Beaconsfield occurs within the quartz-carbonate Tasmania Reef (Lower to Middle Palaeozoic sequence, Hills, 1998). The Henty gold mine is located at the base of the Cambrian Tyndall Group (volcano-sedimentary succession, White and McPhie, 1996) close to Henty Fault. Gold in carbonate samples from Henty ranges from 7.7 to 9360 ppm and in Beaconsfield ranges from 0.01 to 434 ppm. The amount of carbonate in samples from Henty and Beaconsfield gold mines varies from approximately 24 to 99.8%. Bivariate plot of Ca relative to total amounts of Mg, Fe and Mn illustrates that the major carbonate minerals at Beaconsfield and Henty gold mines are magnesian ankerite and calcite. The difference in carbonate mineralogy, at Henty and Beaconsfield gold mines, is attributed to the composition of fluids responsible for carbonate alteration. Gold and magnesium in Beaconsfield ankerite are derived from the leaching of Cambrian ultramafic rocks during the Devonian by the passage of meteoric fluids through tectonically affected Ordovician carbonates (Rao and Adabi, 1999). The total concentration of Fe and Mn are low (0.5 to 2%) in Henty and high (1 to 17.5%) in Beaconsfield ankerite, possibly due to oxidising conditions at Henty and reducing conditions at Beaconsfield gold mines during gold mineralisation. Variation of Sr values between Beaconsfield ankerite and Henty calcite is related to dissolution of limestone that increase Sr concentrations in gold mineralising fluids. Na values in both Beaconsfield (20 to 1100 ppm) and Henty carbonates (25 to 1650 ppm) suggest low salinity fluids responsible for gold

  8. Corrective Action Investigation Plan for Corrective Action Unit 190: Contaminated Waste Sites Nevada Test Site, Nevada, Rev. No.: 0

    International Nuclear Information System (INIS)

    Wickline, Alfred

    2006-01-01

    Corrective Action Unit (CAU) 190 is located in Areas 11 and 14 of the Nevada Test Site, which is 65 miles northwest of Las Vegas, Nevada. Corrective Action Unit 190 is comprised of the four Corrective Action Sites (CASs) listed below: (1) 11-02-01, Underground Centrifuge; (2) 11-02-02, Drain Lines and Outfall; (3) 11-59-01, Tweezer Facility Septic System; and (4) 14-23-01, LTU-6 Test Area. These sites are being investigated because existing information is insufficient on the nature and extent of potential contamination to evaluate and recommend corrective action alternatives. Additional information will be obtained before evaluating corrective action alternatives and selecting the appropriate corrective action for each CAS by conducting a corrective action investigation (CAI). The results of the field investigation will support a defensible evaluation of viable corrective action alternatives that will be presented in the Corrective Action Decision Document. The sites will be investigated based on the data quality objectives (DQOs) developed on August 24, 2006, by representatives of the Nevada Division of Environmental Protection; U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office; Stoller-Navarro Joint Venture, and National Security Technologies, LLC. The DQO process was used to identify and define the type, amount, and quality of data needed to develop and evaluate appropriate corrective actions for CAU 190. The scope of the CAU 190 CAI includes the following activities: (1) Move surface debris and/or materials, as needed, to facilitate sampling; (2) Conduct radiological and geophysical surveys; (3) Perform field screening; (4) Collect and submit environmental samples for laboratory analysis to determine whether contaminants of concern (COCs) are present; (5) If COCs are present, collect additional step-out samples to define the lateral and vertical extent of the contamination; (6) Collect samples of source material, if present

  9. Worth their weight in gold

    International Nuclear Information System (INIS)

    Van Ryssen, E.

    1986-01-01

    A radiotherapeutic method of treating tumours in, on and around the eye, developed and improved over more than a decade of research at the University of Cape Town's Medical School and at the city's Groote Schuur Hospital, has won worldwide recognition. A problem when irradiating eye tumours is that the rays can damage surrounding tissues. Professor Sealy's team overcome this problem by using tailor-made gold or stainless steel shields moulded indiridually to fit the curve of the eyeball of each patient. Depending on the location of the tumour, small radioactive seeds of iodine 125 are placed on the inner or outer curve of the shield in such a way that their rays are confined to the desired location. The number and position of the seeds is worked out to give the desired dose of radiation

  10. Gold nanoparticles: generation and characterization

    International Nuclear Information System (INIS)

    Dey, G.R.

    2013-07-01

    In this presentation we report the reduction of Au 3+ through chemical and free radical (e solv - ) reactions both in non-aqueous and aqueous media. In chemical reduction, the spectral nature in ascorbic acid (AA) and citric acid (CA) systems was different. The band intensity of gold nanoparticles was lower in AA system. While in free radical reaction, the yield of nanoparticles was pure i.e. free from excess reactants. Under the study 60-200 nm size nanoparticles were generated, which are inert to oxygen. Using pulse radiolysis technique, the initial rate for e solv - reaction with Au 3+ was determined to be 7.6 x 10 9 M -1 s -1 . (author)

  11. Extinction Coefficient of Gold Nanostars.

    Science.gov (United States)

    de Puig, Helena; Tam, Justina O; Yen, Chun-Wan; Gehrke, Lee; Hamad-Schifferli, Kimberly

    2015-07-30

    Gold nanostars (NStars) are highly attractive for biological applications due to their surface chemistry, facile synthesis and optical properties. Here, we synthesize NStars in HEPES buffer at different HEPES/Au ratios, producing NStars of different sizes and shapes, and therefore varying optical properties. We measure the extinction coefficient of the synthesized NStars at their maximum surface plasmon resonances (SPR), which range from 5.7 × 10 8 to 26.8 × 10 8 M -1 cm -1 . Measured values correlate with those obtained from theoretical models of the NStars using the discrete dipole approximation (DDA), which we use to simulate the extinction spectra of the nanostars. Finally, because NStars are typically used in biological applications, we conjugate DNA and antibodies to the NStars and calculate the footprint of the bound biomolecules.

  12. Draft Genome Sequence of the Phosphate-Solubilizing Bacterium Pseudomonas argentinensis Strain SA190 Isolated from the Desert Plant Indigofera argentea

    KAUST Repository

    Lafi, Feras Fawzi; Alam, Intikhab; Geurts, Rene; Bisseling, Ton; Bajic, Vladimir B.; Hirt, Heribert; Saad, Maged

    2016-01-01

    Pseudomonas argentinensis strain SA190 is a plant endophytic-inhabiting bacterium that was isolated from root nodules of the desert plant Indigofera argentea collected from the Jizan region of Saudi Arabia. Here, we report the genome sequence of SA

  13. Intensification Behavior of Mercury Ions on Gold Cyanide Leaching

    Directory of Open Access Journals (Sweden)

    Qiang Zhong

    2018-01-01

    Full Text Available Cyanidation is the main method used to extract gold from gold raw materials; however, a serious problem with this method is the low leaching rate. In order to improve gold leaching, the intensification behavior of mercury ions on gold cyanide leaching, for two types of materials, sulphide gold concentrate and oxide gold ore, was investigated. The results showed that mercury ions, with only a 10−5 M dosage, could significantly intensify leaching and gold recovery. The dissolution behavior of gold plate was also intensified by 10−5 M mercury ions. Microstructure analysis showed that mercury ions intensified the cyanidation corrosion of the gold surface, resulting in a loose structure, where a large number of deep ravines and raised particles were evident across the whole gold surface. The loose structure added contact surface between the gold and cyanide, and accelerated gold dissolution. Moreover, mercury ions obstructed the formation of insoluble products, such as AuCN, Au(OHCN, and Au(OHx, that lead to a passivation membrane on the gold surface, reducing contact between the gold and cyanide. These effects, brought about by mercury ions, change the structure and product of the gold surface during gold cyanidation and promote gold leaching.

  14. Enrichment of Gold in Antimony Matte by Direct Smelting of Refractory Gold Concentrate

    Science.gov (United States)

    Yang, Tianzu; Xie, Boyi; Liu, Weifeng; Zhang, Duchao; Chen, Lin

    2018-04-01

    Conventional cyanidation technology achieves low gold recovery when used to process refractory gold concentrate. Based on the geochemical characteristics of gold deposit mineralization, a new method is proposed herein for gold enrichment in antimony matte by smelting of refractory gold concentrate. The effects of the FeO/SiO2 and CaO/SiO2 ratios, smelting temperature, and smelting time on the gold recovery were investigated in detail. The optimum conditions were determined to be FeO/SiO2 ratio of 1.2, CaO/SiO2 ratio of 0.4, smelting temperature of 1200°C, and smelting time of 45 min. The gold content in antimony matte and smelting slag was 96.68 and 1.13 g/t, respectively. The gold, antimony, and arsenic recovery was 97.72%, 26.89%, and 6.56%, respectively, with most of the antimony and arsenic volatilized into dust. Mineral liberation analyzer results showed that the antimony matte mainly consisted of FeS and FeO, with three phases, viz. FeAs, SbAs, and AuSb, embedded between them, indicating that gold was easily enriched with antimony and arsenic during smelting of refractory gold concentrate.

  15. Coal-gold agglomeration: an alternative separation process in gold recovery

    Energy Technology Data Exchange (ETDEWEB)

    Akcil, A.; Wu, X.Q.; Aksay, E.K. [Suleyman Demirel University, Isparta (Turkey). Dept. of Mining Engineering

    2009-07-01

    Considering the increasing environmental concerns and the potential for small gold deposits to be exploited in the future, the uses of environmentally friendly processes are essential. Recent developments point to the potential for greatly increased plant performance through a separation process that combines the cyanide and flotation processes. In addition, this kind of alternative treatment processes to the traditional gold recovery processes may reduce the environmental risks of present small-scale gold mining. Gold recovery processes that applied to different types of gold bearing ore deposits show that the type of deposits plays an important role for the selection of mineral processing technologies in the production of gold and other precious metals. In the last 25 years, different alternative processes have been investigated on gold deposits located in areas where environmental issues are a great concern. In 1988, gold particles were first recovered by successful pilot trial of coal-gold agglomeration (CGA) process in Australia. The current paper reviews the importance of CGA in the production of gold ore and identifies areas for further development work.

  16. Gold Leaching Characteristics and Intensification of a High S and As-Bearing Gold Concentrate

    Science.gov (United States)

    Yang, Yong-bin; Liu, Xiao-liang; Jiang, Tao; Li, Qian; Xu, Bin; Zhang, Yan

    Some high sulfur and arsenic-bearing gold concentrate has a gold leaching rate less than 80% by oxidation roasting-pickling-cyanidation process. The characteristics and intensification of gold leaching were studied systemically. By combining chemical composition and phase analysis, the low gold leaching rate was found to lie in the capsulation of gold by iron-containing phases including iron oxides, arsenopyrite and pyrite. 96.66% of gold in the industrial leaching residue was capsulated and 95.88% of the capsulated turned out to be in the iron-containing phases. The results of laboratory pickling-cyanidation experiments on the calcine and industrial leaching residue presented further demonstration for the fact that gold capsulated in the iron-containing phases was hard to be leached. However, the gold cyanide leaching rate of calcine could be raised over 95% by a reduction roasting-pickling pretreatment which played such a significant role in exposing the capsulated gold that gold leaching was intensified remarkably.

  17. Enrichment of Gold in Antimony Matte by Direct Smelting of Refractory Gold Concentrate

    Science.gov (United States)

    Yang, Tianzu; Xie, Boyi; Liu, Weifeng; Zhang, Duchao; Chen, Lin

    2018-06-01

    Conventional cyanidation technology achieves low gold recovery when used to process refractory gold concentrate. Based on the geochemical characteristics of gold deposit mineralization, a new method is proposed herein for gold enrichment in antimony matte by smelting of refractory gold concentrate. The effects of the FeO/SiO2 and CaO/SiO2 ratios, smelting temperature, and smelting time on the gold recovery were investigated in detail. The optimum conditions were determined to be FeO/SiO2 ratio of 1.2, CaO/SiO2 ratio of 0.4, smelting temperature of 1200°C, and smelting time of 45 min. The gold content in antimony matte and smelting slag was 96.68 and 1.13 g/t, respectively. The gold, antimony, and arsenic recovery was 97.72%, 26.89%, and 6.56%, respectively, with most of the antimony and arsenic volatilized into dust. Mineral liberation analyzer results showed that the antimony matte mainly consisted of FeS and FeO, with three phases, viz. FeAs, SbAs, and AuSb, embedded between them, indicating that gold was easily enriched with antimony and arsenic during smelting of refractory gold concentrate.

  18. c-Myb and its target Bmi1 are required for p190BCR/ABL leukemogenesis in mouse and human cells.

    Science.gov (United States)

    Waldron, T; De Dominici, M; Soliera, A R; Audia, A; Iacobucci, I; Lonetti, A; Martinelli, G; Zhang, Y; Martinez, R; Hyslop, T; Bender, T P; Calabretta, B

    2012-04-01

    Expression of c-Myb is required for normal hematopoiesis and for proliferation of myeloid leukemia blasts and a subset of T-cell leukemia, but its role in B-cell leukemogenesis is unknown. We tested the role of c-Myb in p190(BCR/ABL)-dependent B-cell leukemia in mice transplanted with p190(BCR/ABL)-transduced marrow cells with a c-Myb allele (Myb(f/d)) and in double transgenic p190(BCR/ABL)/Myb(w/d) mice. In both models, loss of a c-Myb allele caused a less aggressive B-cell leukemia. In p190(BCR/ABL)-expressing human B-cell leukemia lines, knockdown of c-Myb expression suppressed proliferation and colony formation. Compared with c-Myb(w/f) cells, expression of Bmi1, a regulator of stem cell proliferation and maintenance, was decreased in pre-B cells from Myb(w/d) p190(BCR/ABL) transgenic mice. Ectopic expression of a mutant c-Myb or Bmi1 enhanced the proliferation and colony formation of Myb(w/d) p190(BCR/ABL) B-cells; by contrast, Bmi1 downregulation inhibited colony formation of p190(BCR/ABL)-expressing murine B cells and human B-cell leukemia lines. Moreover, c-Myb interacted with a segment of the human Bmi1 promoter and enhanced its activity. In blasts from 19 Ph(1) adult acute lymphoblastic leukemia patients, levels of c-Myb and Bmi1 showed a positive correlation. Together, these findings support the existence of a c-Myb-Bmi1 transcription-regulatory pathway required for p190(BCR/ABL) leukemogenesis.

  19. The giant Jiaodong gold province: The key to a unified model for orogenic gold deposits?

    Directory of Open Access Journals (Sweden)

    David I. Groves

    2016-05-01

    Full Text Available Although the term orogenic gold deposit has been widely accepted for all gold-only lode-gold deposits, with the exception of Carlin-type deposits and rare intrusion-related gold systems, there has been continuing debate on their genesis. Early syngenetic models and hydrothermal models dominated by meteoric fluids are now clearly unacceptable. Magmatic-hydrothermal models fail to explain the genesis of orogenic gold deposits because of the lack of consistent spatially – associated granitic intrusions and inconsistent temporal relationships. The most plausible, and widely accepted, models involve metamorphic fluids, but the source of these fluids is hotly debated. Sources within deeper segments of the supracrustal successions hosting the deposits, the underlying continental crust, and subducted oceanic lithosphere and its overlying sediment wedge all have their proponents. The orogenic gold deposits of the giant Jiaodong gold province of China, in the delaminated North China Craton, contain ca. 120 Ma gold deposits in Precambrian crust that was metamorphosed over 2000 million years prior to gold mineralization. The only realistic source of fluid and gold is a subducted oceanic slab with its overlying sulfide-rich sedimentary package, or the associated mantle wedge. This could be viewed as an exception to a general metamorphic model where orogenic gold has been derived during greenschist- to amphibolite-facies metamorphism of supracrustal rocks: basaltic rocks in the Precambrian and sedimentary rocks in the Phanerozoic. Alternatively, if a holistic view is taken, Jiaodong can be considered the key orogenic gold province for a unified model in which gold is derived from late-orogenic metamorphic devolatilization of stalled subduction slabs and oceanic sediments throughout Earth history. The latter model satisfies all geological, geochronological, isotopic and geochemical constraints but the precise mechanisms of auriferous fluid release, like many

  20. Gold nanoparticles produced in a microalga

    International Nuclear Information System (INIS)

    Luangpipat, Tiyaporn; Beattie, Isabel R.; Chisti, Yusuf; Haverkamp, Richard G.

    2011-01-01

    An efficient biological route to production of gold nanoparticles which allows the nanoparticles to be easily recovered remains elusive. Live cells of the green microalga Chlorella vulgaris were incubated with a solution of gold chloride and harvested by centrifugation. Nanoparticles inside intact cells were identified by transmission electron microscopy and confirmed to be metallic gold by synchrotron based X-ray powder diffraction and X-ray absorption spectroscopy. These intracellular gold nanoparticles were 40–60 nm in diameter. At a concentration of 1.4% Au in the alga, a better than 97% recovery of the gold from solution was achieved. A maximum of 4.2% Au in the alga was obtained. Exposure of C. vulgaris to solutions containing dissolved salts of palladium, ruthenium, and rhodium also resulted in the production of the corresponding nanoparticles within the cells. These were surmised to be also metallic, but were produced at a much lower intracellular concentration than achieved with gold. Iridium was apparently toxic to the alga. No nanoparticles were observed using platinum solutions. C. vulgaris provides a possible route to large scale production of gold nanoparticles.

  1. NUCLEATION STUDIES OF GOLD ON CARBON ELECTRODES

    Directory of Open Access Journals (Sweden)

    S. SOBRI

    2008-04-01

    Full Text Available Interest has grown in developing non-toxic electrolytes for gold electrodeposition to replace the conventional cyanide-based bath for long term sustainability of gold electroplating. A solution containing thiosulphate and sulphite has been developed specially for microelectronics applications. However, at the end of the electrodeposition process, the spent electrolyte can contain a significant amount of gold in solution. This study has been initiated to investigate the feasibility of gold recovery from a spent thiosulphate-sulphite electrolyte. We have used flat-plate glassy carbon and graphite electrodes to study the mechanism of nucleation and crystal growth of gold deposition from the spent electrolyte. It was found that at the early stages of reduction process, the deposition of gold on glassy carbon exhibits an instantaneous nucleation of non-overlapping particles. At longer times, the particles begin to overlap and the deposition follows a classic progressive nucleation phenomenon. On the other hand, deposition of gold on graphite does not follow the classical nucleation phenomena.

  2. Nature vs. nurture: gold perpetuates "stemness".

    Science.gov (United States)

    Paul, Willi; Sharma, Chandra P; Deb, Kaushik Dilip

    2011-01-01

    Adult tissues contain quiescent reservoirs of multipotent somatic stem cells and pluripotent embryonic-like stem cells (ELSCs). Credited with regenerative properties gold is used across both -contemporary and -ancient medicines. Here, we show that gold exerted these effects by enhancing the pool of pluripotent ELSC while improving their stemness. We used hESCs as an in-vitro model to understand if gold could enhance self-renewal and pluripotency. Swarna-bhasma (SB), an ancient Indian gold microparticulate (41.1 nm), preparation, reduced spontaneous-differentiation, improved self-renewal, pluripotency and proliferation of hESCs. Colloidal gold-nanoparticles (GNP) (15.59 nm) were tested to confirm that the observations were attributable to nanoparticulate-gold. SB and GNP exposure: maintained -stemness, -karyotypic stability, enhanced pluripotency till day-12, increased average colony-sizes, and reduced the number of autonomously-derived differentiated FGFR1 positive fibroblast-niche-cells/colony. Particulate-gold induced upregulation of FGFR1 and IGF2 expression, and decrease in IGF1 secretion indicates IGF1/2 mediated support for enhanced pluripotency and self-renewal in hESCs.

  3. Urban artisanal gold shops and mercury emissions

    International Nuclear Information System (INIS)

    Cordy, P.; Veiga, M.; Carrasco, V.H.G.

    2008-01-01

    Artisanal miners in developing countries use mercury amalgamation processes to extract gold. The amalgams are then refined before being sold on to urban gold shops. The amalgams can often contain between 2 to 40 per cent mercury. Unburned amalgams are also often sold directly to gold shops. There are serious health risks for shop employees and nearby populations when the gold is melted and further purified. Studies have shown that mercury concentrations in the ambient air of gold shops often exceeds World Health Organization (WHO) limits by an order of magnitude or more. This study examined the practices and technologies used to refine gold in Latin America and Indonesia. The study compared and contrasted various refining methods and their resulting mercury emissions. Methods of reducing mercury emissions were also investigated, including a filtration system designed to capture 80 per cent of mercury emissions. Barriers to implementing mercury emissions reduction plans were also investigated. It was concluded that the design of urban gold shops must include condensers, fume hoods, and efficient mercury capture systems. 15 refs

  4. Phytomining for Artisanal Gold Mine Tailings Management

    Directory of Open Access Journals (Sweden)

    Baiq Dewi Krisnayanti

    2016-08-01

    Full Text Available Mine tailings are generally disposed of by artisanal and small scale gold miners in poorly constructed containment areas and this leads to environmental risk. Gold phytomining could be a possible option for tailings management at artisanal and small-scale gold mining (ASGM locations where plants accumulate residual gold in their above ground biomass. The value of metal recovered from plants could offset some of the costs of environmental management. Getting gold into plants has been repeatedly demonstrated by many research groups; however, a simple working technology to get gold out of plants is less well described. A field experiment to assess the relevance of the technology to artisanal miners was conducted in Central Lombok, Indonesia between April and June 2015. Tobacco was planted in cyanidation tailings (1 mg/kg gold and grown for 2.5 months before the entire plot area was irrigated with NaCN to induce metal uptake. Biomass was then harvested (100 kg, air dried, and ashed by miners in equipment currently used to ash activated carbon at the end of a cyanide leach circuit. Borax and silver as a collector metal were added to the tobacco ash and smelted at high temperature to extract metals from the ash. The mass of the final bullion (39 g was greater than the mass of silver used as a collector (31 g, indicating recovery of metals from the biomass through the smelt process. The gold yield of this trial was low (1.2 mg/kg dry weight biomass concentration, indicating that considerable work must still be done to optimise valuable metal recovery by plants at the field scale. However, the described method to process the biomass was technically feasible, and represents a valid technique that artisanal and small-scale gold miners are willing to adopt if the economic case is good.

  5. Electrochemical Oxidation of Glycerol Using Gold Electrode

    International Nuclear Information System (INIS)

    Mohamed Rozali Othman; Amirah Ahmad

    2015-01-01

    Cyclic voltammetry, potential linear V and chronocuolometry methods were carried out to gain electrochemical behavior of glycerol at a gold electrode. Potassium hydroxide and sulfuric acid were chosen to be the electrolyte for the electro-oxidation of this organic compound. Besides gold plate electrode, gold composite electrode (Au-PVC) was also used as the working electrode. The Au-PVC composite electrode was characterized by Scanning Electron Microscopy (SEM) to determine its morphological aspects before and after used in electrochemical oxidation of glycerol. In alkaline solution, the adsorption of hydroxide species onto the surface of both gold plate and composite Au-PVC electrodes occurs at potential around 500 mV vs SCE. However, at gold plate electrode, there was a small, broad peak before the drastic escalation of current densities which indicates the charge transfer of the chemisorbed OH - anion. In acidic media, the gold oxide was formed after potential 1.0 V. From the cyclic voltammogram glycerol undergo oxidation twice in potassium hydroxide at gold plate and Au-PVC composite electrodes, while in sulfuric acid, oxidation reaction happened once for glycerol on the gold plate electrode. Overall, electrochemical oxidation of glycerol was more effective in alkaline media. Tafel graph which plotted from potential linear V method shows that Au-PVC composite electrode is better than gold plate electrode for the electro-oxidation of glycerol in alkaline solution. Electrochemical oxidation of glycerol products as analyzed by Gas Chromatography-Mass Spectrometry (GC-MS) produced several carboxylic acids and phenolic compounds. (author)

  6. Synthesis of gold nanoparticles with graphene oxide.

    Science.gov (United States)

    Wang, Wenshuo; He, Dawei; Zhang, Xiqing; Duan, Jiahua; Wu, Hongpeng; Xu, Haiteng; Wang, Yongsheng

    2014-05-01

    Single sheets of functionalized graphene oxide are derived through chemical exfoliation of natural flake graphite. We present an effective synthetic method of graphene-gold nanoparticles hybrid nanocomposites. AFM (Atomic Force Microscope) was used to measure the thickness of the individual GO nanosheet. FTIR (Fourier transform infrared) spectroscopy was used to verify the attachment of oxygen functionalities on the surface of graphene oxide. TEM (Transmission Electron Microscope) data revealed the average diameters of the gold colloids and characterized the composite particles situation. Absorption spectroscopy showed that before and after synthesis the gold particle size did not change. Our studies indicate that the hybrid is potential substrates for catalysts and biosensors.

  7. Biosynthesis of Gold Nanoparticles Using Pseudomonas Aeruginosa

    International Nuclear Information System (INIS)

    Abd El-Aziz, M.; Badr, Y.; Mahmoud, M. A.

    2007-01-01

    Pseudomonas aeruginosa were used for extracellular biosynthesis of gold nanoparticles (Au NPs). Consequently, Au NPs were formed due to reduction of gold ion by bacterial cell supernatant of P. aeruginos ATCC 90271, P. aeruginos (2) and P. aeruginos (1). The UV-Vis. and fluorescence spectra of the bacterial as well as chemical prepared Au NPs were recorded. Transmission electron microscopy (TEM) micrograph showed the formation of well-dispersed gold nanoparticles in the range of 15-30 nm. The process of reduction being extracellular and may lead to the development of an easy bioprocess for synthesis of Au NPs

  8. The giant Kalgoorlie Gold Field revisited

    Directory of Open Access Journals (Sweden)

    Noreen Mary Vielreicher

    2016-05-01

    Direct timing constraints on gold mineralization indicate that Fimiston- and Mt Charlotte-style mineralization formed within a relative short period of time around 2.64 Ga, and, as such, support a model of progressive deformation of a rheologically heterogeneous rock package late in the structural history. Fluid characteristics, combined with the structural, metamorphic and absolute timing, support description of gold mineralization at the Golden Mile as orogenic and mesozonal, and this allows direct correlation with orogenic gold deposits worldwide, which classically formed during accretion along convergent margins throughout Earth history.

  9. Nondestructive analysis of the gold quarter liras

    International Nuclear Information System (INIS)

    Cakir, C.; Guerol, A.; Demir, L.; Sahin, Y.

    2009-01-01

    In this study, we have prepared seven Au-Cu standards in the concentration range of 18-24 (as carat) for nondestructive control of gold quarter liras. Some calibration curves for quantitative analysis of Au in the gold quarter liras that commercially present in Turkey have been plotted using these standard samples. The characteristic X-rays of Au and Cu emitted from these standard samples and the test sample with known composition are recorded by using a Ge(Li) detector. These calibration curves provide a nondestructive analysis of gold quarter liras with the uncertainties about 1.18%. (author)

  10. Refractory concentrate gold leaching: Cyanide vs. bromine

    Science.gov (United States)

    Dadgar, Ahmad

    1989-12-01

    Gold extraction, recovery and economics for two refractory concentrates were investigated using cyanide and bromine reagents. Gold extractions for cyanide leaching (24-48 hours) and bromine leaching (six hours) were the same and ranged from 94 to 96%. Gold recoveries from bromine pregnant solutions using carbon adsorption, ion exchange, solvent extraction, and zinc and aluminum precipitation methods were better than 99.9%. A preliminary economic analysis indicates that chemical costs for cyanidation and bromine process are 11.70 and 11.60 respectively, per tonne of calcine processed.

  11. Gold's monetary roll will be strengthened - Plumbridge

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    Delivering his Presidential address at the Chamber's annual general meeting, Mr Plumbridge said the gold market would enter a new phase and listed seven reasons why gold's monetary role would be strengthened. There was a dramatic increase in the demand for gold jewellery. He also forecasted that South African uranium production would again attain its former peak annual production of about 6000t. There is an essential need for a sustained growth in nuclear power and the prospects for uranium mining industry remain encouraging

  12. Gold nanoparticles extraction from dielectric scattering background

    Science.gov (United States)

    Hong, Xin; Wang, Jingxin

    2014-11-01

    The unique advantages such as brightness, non-photobleaching, good bio-compatibility make gold nanoparticles desirable labels and play important roles in biotech and related research and applications. Distinguishing gold nanoparticles from other dielectric scattering particles is of more importance, especially in bio-tracing and imaging. The enhancement image results from the localized surface plasmon resonance associated with gold nanopartilces makes themselves distinguishable from other dielectric particles, based on which, we propose a dual-wavelength detection method by employing a high sensitive cross-polarization microscopy.

  13. Gold Photoluminescence: Wavelength and Polarization Engineering

    DEFF Research Database (Denmark)

    Andersen, Sebastian Kim Hjælm; Pors, Anders Lambertus; Bozhevolnyi, Sergey I.

    2015-01-01

    We demonstrate engineering of the spectral content and polarization of photoluminescence (PL) from arrayed gold nanoparticles atop a subwavelength-thin dielectric spacer and optically-thick gold film, a configuration that supports gap-surface plasmon resonances (GSPRs). Choice of shapes...... and dimensions of gold nanoparticles influences the GSPR wavelength and polarization characteristics, thereby allowing us to enhance and spectrally mold the plasmon-assisted PL while simultaneously controlling its polarization. In order to understand the underlying physics behind the plasmon-enhanced PL, we...

  14. Nuclear analyses of the Pietroasa gold hoard

    International Nuclear Information System (INIS)

    Cojocaru, V.; Besliu, C.

    1999-01-01

    By means of nuclear analyses the concentrations of Au, Ag, Cu, Ir, Os, Pt, Co and Hg were measured in the 12 artifacts of the gold hoard discovered in 1837 at Pietroasa, Buzau country in Romania. The concentrations of the first four elements were used to compare different stylistic groups assumed by historians. Comparisons with gold nuggets from the old Dacian territory and gold Roman imperial coins were also made. A good agreement was found with the oldest hypothesis which considers that the hoard is represented by three styles appropriated mainly by the Goths. (author)

  15. MRI-detection rate and incidence of lumbar bleeding sources in 190 patients with non-aneurysmal SAH.

    Directory of Open Access Journals (Sweden)

    Sepide Kashefiolasl

    Full Text Available Up to 15% of all spontaneous subarachnoid hemorrhages (SAH have a non-aneurysmal SAH (NASAH. The evaluation of SAH patients with negative digital subtraction angiography (DSA is sometimes a diagnostic challenge. Our goal in this study was to reassess the yield of standard MR-imaging of the complete spinal axis to rule out spinal bleeding sources in patients with NASAH.We retrospectively analyzed the spinal MRI findings in 190 patients with spontaneous NASAH, containing perimesencephalic (PM and non-perimesencephalic (NPM SAH, diagnosed by computer tomography (CT and/or lumbar puncture (LP, and negative 2nd DSA.190 NASAH patients were included in the study, divided into PM-SAH (n = 87; 46% and NPM-SAH (n = 103; 54%. Overall, 23 (22% patients had a CT negative SAH, diagnosed by positive LP. MR-imaging of the spinal axis detected two patients with lumbar ependymoma (n = 2; 1,05%. Both patients complained of radicular sciatic pain. The detection rate raised up to 25%, if only patients with radicular sciatic pain received an MRI.Routine radiological investigation of the complete spinal axis in NASAH patients is expensive and can not be recommended for standard procedure. However, patients with clinical signs of low-back/sciatic pain should be worked up for a spinal pathology.

  16. Determination of the bandheads spin and investigation of identical bands for Even - A nuclei of the superdeformed mass region 190

    International Nuclear Information System (INIS)

    Shalaby, A.S.

    2005-01-01

    Using the three-parameter expression of harris expansion of the rotational energy, the dynamical moment of inertia is represented by a power-series expansion in even powers of the rotational frequency. The three expansion coefficients were determined by using Marquardt method of nonlinear least-squares routines, to fit the proposed dynamical moment of inertia with its recent experimental data for the superdeformed (SD) nuclei in the A 190 mass region. The calculated dynamical moment of inertia with the best parameters is then integrated to obtain the spin, which in turn was used to determine the static moment of inertia. The comparison of the dynamic moment of inertia and spin with their available experimental data shows good agreements between them. These procedures were succeedingly done for nine superdeformed bands in the A 190 nuclei: 1 90Hg(B1, B3), 1 94PB(B1, B2, B3), 1 96PB(B1, B2, B3), 1 94PB(B1, B22, B3), 1 96BP((B1, B2, B3) and 1 98PO. We have also investigated the identity exist among these SD bands. It was shown that some of these SD bands are identical to each other

  17. Coal-oil gold agglomeration assisted flotation to recover gold from refractory ore

    Science.gov (United States)

    Otsuki, A.; Yue, C.

    2017-07-01

    This study aimed to investigate the applicability of coal-oil gold agglomeration (CGA) assisted flotation to recover gold from a refractory ore. The ore with the grade of 2-5 g/t was tested with the CGA-flotation process in six different size fractions from 38 to 300 urn using different collector types and dosages. In addition, the flotation without CGA was performed under the same condition for comparison. The results showed that the higher gold grade and recovery were achieved by applying the CGA-flotation, compared with the flotation without CGA. More than 20-60 times grade increase from the head grade was obtained with CGA-flotation. The elemental analysis of gold and sulphur explained their relationship with gold recovery. The results well indicated the applicability of CGA to upgrade the refractory gold ore.

  18. Gold deposit styles and placer gold characterisation in northern and east-central Madagascar

    Science.gov (United States)

    Pitfield, Peter E. J; Styles, Michael T.; Taylor, Cliff D.; Key, Roger M.; Bauer,; Ralison, A

    2009-01-01

    Microchemical characterisation of bedrock and placer gold grains from six gold districts within the Archaean domains and intervening Neoproterozoic Anaboriana-Manampotsy belt of northern and east-central Madagascar show few opaque inclusions (e.g pyrrhotite, Bi tellurides) but wide range of Ag contents (40wt%). Some districts exhibit multiple source populations of grains. The ‘greenstone belt’ terranes have an orogenic gold signature locally with an intrusion-related to epithermal overprint. Proterozoic metasediments with felsic to ultramafic bodies yield dominantly intrusion-related gold. A high proportion of secondary gold (<0.5wt% Ag) is related to recycling of paleoplacers and erosion of post-Gondwana planation surfaces and indicates that some mesothermal gold systems were already partially to wholly removed by erosion by the PermoTriassic.

  19. Effects of dissolucytotic gold ions on recovering brain lesions.

    Science.gov (United States)

    Danscher, Gorm; Larsen, Agnete

    2010-04-01

    Recent experimental research has shown that metallic gold releases charged gold atoms when placed intracerebrally and that the liberated gold ions affect inflammation in the brain. The observations suggest that metallic gold can be used as a safe suppressor of inflammation in the central nervous system.

  20. Electroplating of gold using a sulfite-based electrolyte

    NARCIS (Netherlands)

    Smalbrugge, E.; Jacobs, B.; Falcone, S.; Geluk, E.J.; Karouta, F.; Leijtens, X.J.M.; Besten, den J.H.

    2000-01-01

    Electroplating of gold is often used in optoelectronic and microelectronic devices for air-bridges, heat-sinks or gold-bumps for flip-chip techniques. The gold-cyanide electrolytes, which are commonly used in gold-electroplating, are toxic and attack resist patterns causing cracks during the plating

  1. A study on gold detection in Wenyu gold mine with XRF techniques

    International Nuclear Information System (INIS)

    Liu Liuchun

    1988-01-01

    A portable X ray fluorescence analyzer was used for detecting fluorcescent X rays from the elements associated with gold ores. Fe, As and Ni were chosen to be the indicator elements to analyse rock samples in Wenyu gold mine. Optimum indicators were determined, and it had proved to be successful to detect gold indirectly by measuring the yields of characteristic X rays of the elements. The method provided also valuable information on geology mapping and deposits forming environment

  2. Electrocatalytic glucose oxidation at gold and gold-carbon nanoparticulate film prepared from oppositely charged nanoparticles

    International Nuclear Information System (INIS)

    Karczmarczyk, Aleksandra; Celebanska, Anna; Nogala, Wojciech; Sashuk, Volodymyr; Chernyaeva, Olga; Opallo, Marcin

    2014-01-01

    Graphical abstract: - Highlights: • Gold nanoparticulate film electrodes were prepared by layer-by-layer method from oppositely charged nanoparticles. • Positively charged nanoparticles play dominant role in glucose oxidation in alkaline solution. • Gold and gold-carbon nanoparticulate film electrodes exhibit similar glucose oxidation current and onset potential. - Abstract: Electrocatalytic oxidation of glucose was studied at nanoparticulate gold and gold-carbon film electrodes. These electrodes were prepared by a layer-by-layer method without application of any linker molecules. Gold nanoparticles were stabilized by undecane thiols functionalized by trimethyl ammonium or carboxylate groups, whereas the carbon nanoparticles were covered by phenylsulfonate functionalities. The gold nanoparticulate electrodes were characterized by UV-vis and XPS spectroscopy, atomic force microscopy and voltammetry, before and after heat-treatment. Heat-treatment facilitates the aggregation of the nanoparticles and affects the structure of the film. The comparison of the results obtained with film electrodes prepared from gold nanoparticles with the same charge and with gold-carbon nanoparticulate electrodes, proved that positively charged nanoparticles are responsible for the high electrocatalytic activity, whereas negatively charged ones act rather as a linker of the film

  3. Formation of gold nanorods and gold nanorod films for surface-enhanced Raman scattering spectroscopy

    International Nuclear Information System (INIS)

    Trotsyuk, L.L.; Kulakovich, O.S.; Shabunya-Klyachkovskaya, E.V.; Gaponenko, S.V.; Vashchenko, S.V.

    2016-01-01

    The formation of gold nanorods as well as thin films prepared via electrostatic deposition of gold nanorods has been investigated. The obtained gold nanorods films have been used as substrates for the surface-enhanced Raman scattering analysis of sulfur-free organic molecules mitoxantrone and malachite green as well as inorganic malachite microcrystals for the first time. The additional modification of films with L-cysteine allows one to significantly extend the use of gold nanorods for the surface-enhanced Raman scattering analysis. (authors)

  4. EOP Gold Coral (Gerardia sp.) Growth Measurements

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gold coral (Gerardia sp.) trees that were inspected years earlier on Pisces submersible dives were revisited and their change in size measured. The fishery for...

  5. Poly-thiosemicarbazide membrane for gold recovery

    KAUST Repository

    Villalobos, Luis Francisco; Yapici, Tahir; Peinemann, Klaus-Viktor

    2014-01-01

    A novel polymeric membrane adsorber with a high density of adsorption sites that can selectively capture Au(III) ions, is proposed as an efficient alternative to recover gold from dilute solutions. Poly-thiosemicarbazide (PTSC), a polymer

  6. Lamellar multilayer hexadecylaniline-modified gold nanoparticle ...

    Indian Academy of Sciences (India)

    standard Wilhelmy plate was used for surface pressure sensing. Multilayer ... carried out on a JEOL model 1200EX instrument operated at an accelerating voltage of ... the gold nanoparticles within domains (and reorganization of the domains ...

  7. A new route to gold nanoflowers

    Science.gov (United States)

    Liebig, Ferenc; Henning, Ricky; Sarhan, Radwan M.; Prietzel, Claudia; Bargheer, Matias; Koetz, Joachim

    2018-05-01

    Catanionic vesicles spontaneously formed by mixing the anionic surfactant bis(2-ethylhexyl) sulfosuccinate sodium salt with the cationic surfactant cetyltrimethylammonium bromide were used as a reducing medium to produce gold clusters, which are embedded and well-ordered into the template phase. The gold clusters can be used as seeds in the growth process that follows by adding ascorbic acid as a mild reducing component. When the ascorbic acid was added very slowly in an ice bath round-edged gold nanoflowers were produced. When the same experiments were performed at room temperature in the presence of Ag+ ions, sharp-edged nanoflowers could be synthesized. The mechanism of nanoparticle formation can be understood to be a non-diffusion-limited Ostwald ripening process of preordered gold nanoparticles embedded in catanionic vesicle fragments. Surface-enhanced Raman scattering experiments show an excellent enhancement factor of 1.7 · 105 for the nanoflowers deposited on a silicon wafer.

  8. Deep gold mine fracture zone behaviour

    CSIR Research Space (South Africa)

    Napier, JAL

    1998-12-01

    Full Text Available The investigation of the behaviour of the fracture zone surrounding deep level gold mine stopes is detailed in three main sections of this report. Section 2 outlines the ongoing study of fundamental fracture process and their numerical...

  9. Optical properties of spherical gold mesoparticles

    DEFF Research Database (Denmark)

    Evlyukhin, A. B.; Kuznetsov, A. I.; Novikov, S. M.

    2012-01-01

    Optical properties of spherical gold particles with diameters of 150-650 nm (mesoparticles) are studied by reflectance spectroscopy. Particles are fabricated by laser-induced transfer of metallic droplets onto metal and dielectric substrates. Contributions of higher multipoles (beyond...

  10. Adsorption-induced restructuring of gold nanochains

    DEFF Research Database (Denmark)

    Bahn, Sune Rastad; Lopez, Nuria; Nørskov, Jens Kehlet

    2002-01-01

    The chemical properties of single-atomic chains of gold atoms are investigated using density functional calculations. The nanochains are shown to be unusually chemically active with strong chemisorption of oxygen atoms and carbon monoxide. The chemisorption energies vary significantly with the st......The chemical properties of single-atomic chains of gold atoms are investigated using density functional calculations. The nanochains are shown to be unusually chemically active with strong chemisorption of oxygen atoms and carbon monoxide. The chemisorption energies vary significantly...... with the strain/stress conditions for the chain. Oxygen atoms are found to energetically prefer to get incorporated into a chain forming a new type of gold-oxygen nanochain with a conductance of one quantum unit. We suggest that the long bond lengths observed in electron microscopy investigations of gold chains...

  11. Synthesis method of asymmetric gold particles.

    Science.gov (United States)

    Jun, Bong-Hyun; Murata, Michael; Hahm, Eunil; Lee, Luke P

    2017-06-07

    Asymmetric particles can exhibit unique properties. However, reported synthesis methods for asymmetric particles hinder their application because these methods have a limited scale and lack the ability to afford particles of varied shapes. Herein, we report a novel synthetic method which has the potential to produce large quantities of asymmetric particles. Asymmetric rose-shaped gold particles were fabricated as a proof of concept experiment. First, silica nanoparticles (NPs) were bound to a hydrophobic micro-sized polymer containing 2-chlorotritylchloride linkers (2-CTC resin). Then, half-planar gold particles with rose-shaped and polyhedral structures were prepared on the silica particles on the 2-CTC resin. Particle size was controlled by the concentration of the gold source. The asymmetric particles were easily cleaved from the resin without aggregation. We confirmed that gold was grown on the silica NPs. This facile method for synthesizing asymmetric particles has great potential for materials science.

  12. Biological synthesis and characterization of intracellular gold ...

    Indian Academy of Sciences (India)

    thods of reduction of metal ions using plants or microorganisms are often ... have several advantages over bacteria, they are often pre- ferred. ... in static condition for a period of 7 days. ... work was focused on the production of intracellular gold.

  13. 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.

  14. The Modern Monetary System and Gold

    Directory of Open Access Journals (Sweden)

    N N Rubtsov

    2013-12-01

    Full Text Available The article considers the nature of modern money, analyzes the mechanism of its creation, showing that it is basically generated by credit and the principle of partial bank reserve. The article draws comparative parallels between trade money based on gold and contemporary, credit money; the author quotes leading bankers and finance experts on the need for partial return to the principles of functioning of the gold standard as the most effective institute of regulating the monetary system in society.

  15. Optical Epitaxial Growth of Gold Nanoparticle Arrays.

    Science.gov (United States)

    Huang, Ningfeng; Martínez, Luis Javier; Jaquay, Eric; Nakano, Aiichiro; Povinelli, Michelle L

    2015-09-09

    We use an optical analogue of epitaxial growth to assemble gold nanoparticles into 2D arrays. Particles are attracted to a growth template via optical forces and interact through optical binding. Competition between effects determines the final particle arrangements. We use a Monte Carlo model to design a template that favors growth of hexagonal particle arrays. We experimentally demonstrate growth of a highly stable array of 50 gold particles with 200 nm diameter, spaced by 1.1 μm.

  16. Synthesis of radioactive gold nanoparticle in surfactant medium

    International Nuclear Information System (INIS)

    Swadesh Mandal

    2014-01-01

    The present study describes the synthesis of radioactive gold nanoparticle in surfactant medium. Proton irradiated stable 197 Au and radioactive 198 Au were simultaneously used for production of radioactive gold nanoparticle. Face centered cubic gold nanoparticles with size of 4-50 nm were found in proton irradiated gold foil. However, the size of nanoparticle varies with pH using both stable and radioactive gold. (author)

  17. Study on Sumbawa gold recovery using centrifuge

    Science.gov (United States)

    Ferdana, A. D.; Petrus, H. T. B. M.; Bendiyasa, I. M.; Prijambada, I. D.; Hamada, F.; Sachiko, T.

    2018-01-01

    The Artisanal Small Gold Mining in Sumbawa has been processing gold with mercury (Hg), which poses a serious threat to the mining and global environment. One method of gold processing that does not use mercury is by gravity method. Before processing the ore first performed an analysis of Mineragraphy and analysis of compound with XRD. Mineragraphy results show that gold is associated with chalcopyrite and covelite and is a single particle (native) on size 58.8 μm, 117 μm up to 294 μm. characterization with XRD shows that the Sumbawa Gold Ore is composed of quartz, pyrite, pyroxene, and sericite compounds. Sentrifugation is one of separation equipment of gravity method to increase concentrate based on difference of specific gravity. The optimum concentration result is influenced by several variables, such as water flow rate and particle size. In this present research, the range of flow rate is 5 lpm and 10 lpm, the particle size - 100 + 200 mesh and -200 +300 mesh. Gold concentration in concentrate is measured by EDX. The result shows that the optimum condition is obtained at a separation with flow rate 5 lpm and a particle size of -100 + 200 mesh.

  18. Analysis on the Impact of the Fluctuation of the International Gold Prices on the Chinese Gold Stocks

    Directory of Open Access Journals (Sweden)

    Jiankang Jin

    2014-01-01

    Full Text Available Five gold stocks in Chinese Shanghai and Shenzhen A-share and Comex gold futures are chosen to form the sample, for the purpose of analysing the impact of the fluctuation of the international gold prices on the gold stocks in Chinese Shanghai and Shenzhen A-share. Using the methods of unit root test, Granger causality test, VAR model, and impulse response function, this paper has analysed the relationship between the price change of the international gold futures and the price fluctuation of gold stocks in Chinese Shanghai and Shenzhen comprehensively. The results suggest the fluctuation of the international gold futures has a strong influence on the domestic futures.

  19. Up-Regulation of MicroRNA-190b Plays a Role for Decreased IGF-1 That Induces Insulin Resistance in Human Hepatocellular Carcinoma

    Science.gov (United States)

    Hung, Tzu-Min; Ho, Cheng-Maw; Liu, Yen-Chun; Lee, Jia-Ling; Liao, Yow-Rong; Wu, Yao-Ming; Ho, Ming-Chih; Chen, Chien-Hung; Lai, Hong-Shiee; Lee, Po-Huang

    2014-01-01

    Background & Aims Insulin-like growth factor, (IGF)-1, is produced mainly by the liver and plays important roles in promoting growth and regulating metabolism. Previous study reported that development of hepatocellular carcinoma (HCC) was accompanied by a significant reduction in serum IGF-1 levels. Here, we hypothesized that dysregulation of microRNAs (miRNA) in HCC can modulate IGF-1 expression post-transcriptionally. Methods The miRNAs expression profiles in a dataset of 29 HCC patients were examined using illumina BeadArray. Specific miRNA (miR)-190b, which was significantly up-regulated in HCC tumor tissues when compared with paired non-tumor tissues, was among those predicted to interact with 3′-untranslated region (UTR) of IGF-1. In order to explore the regulatory effects of miR-190b on IGF-1 expression, luciferase reporter assay, quantitative real-time PCR, western blotting and immunofluorecence analysis were performed in HCC cells. Results Overexpression of miR-190b in Huh7 cells attenuated the expression of IGF-1, whereas inhibition of miR-190b resulted in up-regulation of IGF-1. Restoration of IGF-1 expression reversed miR-190b-mediated impaired insulin signaling in Huh7 cells, supporting that IGF-1 was a direct and functional target of miR-190b. Additionally, low serum IGF-1 level was associated with insulin resistance and poor overall survival in HCC patients. Conclusions Increased expression of miR-190 may cause decreased IGF-1 in HCC development. Insulin resistance appears to be a part of the physiopathologic significance of decreased IGF-1 levels in HCC progression. This study provides a novel miRNA-mediated regulatory mechanism for controlling IGF-1 expression in HCC and elucidates the biological relevance of this interaction in HCC. PMID:24586785

  20. Gold Nanocages for Biomedical Applications**

    Science.gov (United States)

    Skrabalak, Sara E.; Chen, Jingyi; Au, Leslie; Lu, Xianmao; Li, Xingde; Xia, Younan

    2008-01-01

    Nanostructured materials provide a promising platform for early cancer detection and treatment. Here we highlight recent advances in the synthesis and use of Au nanocages for such biomedical applications. Gold nanocages represent a novel class of nanostructures, which can be prepared via a remarkably simple route based on the galvanic replacement reaction between Ag nanocubes and HAuCl4. The Au nanocages have a tunable surface plasmon resonance peak that extends into the near-infrared, where the optical attenuation caused by blood and soft tissue is essentially negligible. They are also biocompatible and present a well-established surface for easy functionalization. We have tailored the scattering and absorption cross-sections of Au nanocages for use in optical coherence tomography and photothermal treatment, respectively. Our preliminary studies show greatly improved spectroscopic image contrast for tissue phantoms containing Au nanocages. Our most recent results also demonstrate the photothermal destruction of breast cancer cells in vitro by using immuno-targeted Au nanocages as an effective photo-thermal transducer. These experiments suggest that Au nanocages may be a new class of nanometer-sized agents for cancer diagnosis and therapy. PMID:18648528

  1. Gold Nanocages for Biomedical Applications.

    Science.gov (United States)

    Skrabalak, Sara E; Chen, Jingyi; Au, Leslie; Lu, Xianmao; Li, Xingde; Xia, Younan

    2007-10-17

    Nanostructured materials provide a promising platform for early cancer detection and treatment. Here we highlight recent advances in the synthesis and use of Au nanocages for such biomedical applications. Gold nanocages represent a novel class of nanostructures, which can be prepared via a remarkably simple route based on the galvanic replacement reaction between Ag nanocubes and HAuCl(4). The Au nanocages have a tunable surface plasmon resonance peak that extends into the near-infrared, where the optical attenuation caused by blood and soft tissue is essentially negligible. They are also biocompatible and present a well-established surface for easy functionalization. We have tailored the scattering and absorption cross-sections of Au nanocages for use in optical coherence tomography and photothermal treatment, respectively. Our preliminary studies show greatly improved spectroscopic image contrast for tissue phantoms containing Au nanocages. Our most recent results also demonstrate the photothermal destruction of breast cancer cells in vitro by using immuno-targeted Au nanocages as an effective photo-thermal transducer. These experiments suggest that Au nanocages may be a new class of nanometer-sized agents for cancer diagnosis and therapy.

  2. The Kolar Gold Field experiment

    International Nuclear Information System (INIS)

    Sreekantan, B.V.

    1982-01-01

    Meson theory was propounded to explain the nuclear force which holds neutrons and protons inside the nucleus. Subsequently, quark theory was put forward to bring some order into an enormously large number of fundamental particles discovered in the hadron family. These two theories are briefly explained. The gravitational force, the electromagnetic force, the weak nuclear force and the strong nuclear force are the basic forces which determine the behaviour of fundamental particles when they are in close proximity. If the last three of the above-mentioned four forces are one or just different aspects of a single force, quarks and leptons can be mingled in the same theoretical framework indicating the non-conservation of baryon number and the spontaneous decay of the proton into leptons. In order to test the last possibility i.e. proton decay, an experiment has been set up in the Kolar Gold Field at a depth of 2300 metres in India. 1650 gas proportional counters are sandwiched between iron plates. The total amount of iron in the form of iron plates and walls of the counters is 140 tons. In this experiment, nuclei of iron are serving as the source of protons and neutrons and the depth eliminates the background events which mimic proton decay. The amount of iron used in the experiment i.e. 140 tons is more than enough to obtain evidence of 10 proton decay events in a year, assuming that the lifetime of proton is 10 30 years or below. (M.G.B.)

  3. Curcumin: the Indian solid gold.

    Science.gov (United States)

    Aggarwal, Bharat B; Sundaram, Chitra; Malani, Nikita; Ichikawa, Haruyo

    2007-01-01

    Turmeric, derived from the plant Curcuma longa, is a gold-colored spice commonly used in the Indian subcontinent, not only for health care but also for the preservation of food and as a yellow dye for textiles. Curcumin, which gives the yellow color to turmeric, was first isolated almost two centuries ago, and its structure as diferuloylmethane was determined in 1910. Since the time of Ayurveda (1900 Bc) numerous therapeutic activities have been assigned to turmeric for a wide variety of diseases and conditions, including those of the skin, pulmonary, and gastrointestinal systems, aches, pains, wounds, sprains, and liver disorders. Extensive research within the last half century has proven that most of these activities, once associated with turmeric, are due to curcumin. Curcumin has been shown to exhibit antioxidant, anti-inflammatory, antiviral, antibacterial, antifungal, and anticancer activities and thus has a potential against various malignant diseases, diabetes, allergies, arthritis, Alzheimer's disease, and other chronic illnesses. These effects are mediated through the regulation of various transcription factors, growth factors, inflammatory cytokines, protein kinases, and other enzymes. Curcumin exhibits activities similar to recently discovered tumor necrosis factor blockers (e.g., HUMIRA, REMICADE, and ENBREL), a vascular endothelial cell growth factor blocker (e.g., AVASTIN), human epidermal growth factor receptor blockers (e.g., ERBITUX, ERLOTINIB, and GEFTINIB), and a HER2 blocker (e.g., HERCEPTIN). Considering the recent scientific bandwagon that multitargeted therapy is better than monotargeted therapy for most diseases, curcumin can be considered an ideal "Spice for Life".

  4. Predicting superdeformed rotational band-head spin in A ∼ 190 mass region using variable moment of inertia model

    International Nuclear Information System (INIS)

    Uma, V.S.; Goel, Alpana; Yadav, Archana; Jain, A.K.

    2016-01-01

    The band-head spin (I 0 ) of superdeformed (SD) rotational bands in A ∼ 190 mass region is predicted using the variable moment of inertia (VMI) model for 66 SD rotational bands. The superdeformed rotational bands exhibited considerably good rotational property and rigid behaviour. The transition energies were dependent on the prescribed band-head spins. The ratio of transition energies over spin Eγ/ 2 I (RTEOS) vs. angular momentum (I) have confirmed the rigid behaviour, provided the band-head spin value is assigned correctly. There is a good agreement between the calculated and the observed transition energies. This method gives a very comprehensive interpretation for spin assignment of SD rotational bands which could help in designing future experiments for SD bands. (author)

  5. g factors and the interplay of collective and single-particle degrees of freedom in superdeformed mass-190 nuclei

    International Nuclear Information System (INIS)

    Sun, Yang; Zhang, Jing-ye; Guidry, Mike

    2001-01-01

    Interplay of collective and single-particle degrees of freedom is a common phenomenon in strongly correlated many-body systems. Despite many successful efforts in the study of superdeformed nuclei, there is still unexplored physics that can be best understood only through the nuclear magnetic properties. We point out that study of the gyromagnetic factor (g factor) may open a unique opportunity for understanding superdeformed structure. Our calculations suggest that investigation of the g-factor dependence on spin and particle number can provide important information on single-particle structure and its interplay with collective motion in the superdeformed mass-190 nuclei. Modern experimental techniques combined with the new generation of sensitive detectors should be capable of testing our predictions

  6. Subchronic inhalation toxicity of gold nanoparticles

    Directory of Open Access Journals (Sweden)

    Chung Yong

    2011-05-01

    Full Text Available Abstract Background Gold nanoparticles are widely used in consumer products, including cosmetics, food packaging, beverages, toothpaste, automobiles, and lubricants. With this increase in consumer products containing gold nanoparticles, the potential for worker exposure to gold nanoparticles will also increase. Only a few studies have produced data on the in vivo toxicology of gold nanoparticles, meaning that the absorption, distribution, metabolism, and excretion (ADME of gold nanoparticles remain unclear. Results The toxicity of gold nanoparticles was studied in Sprague Dawley rats by inhalation. Seven-week-old rats, weighing approximately 200 g (males and 145 g (females, were divided into 4 groups (10 rats in each group: fresh-air control, low-dose (2.36 × 104 particle/cm3, 0.04 μg/m3, middle-dose (2.36 × 105 particle/cm3, 0.38 μg/m3, and high-dose (1.85 × 106 particle/cm3, 20.02 μg/m3. The animals were exposed to gold nanoparticles (average diameter 4-5 nm for 6 hours/day, 5 days/week, for 90-days in a whole-body inhalation chamber. In addition to mortality and clinical observations, body weight, food consumption, and lung function were recorded weekly. At the end of the study, the rats were subjected to a full necropsy, blood samples were collected for hematology and clinical chemistry tests, and organ weights were measured. Cellular differential counts and cytotoxicity measurements, such as albumin, lactate dehydrogenase (LDH, and total protein were also monitored in a cellular bronchoalveolar lavage (BAL fluid. Among lung function test measurements, tidal volume and minute volume showed a tendency to decrease comparing control and dose groups during the 90-days of exposure. Although no statistically significant differences were found in cellular differential counts, histopathologic examination showed minimal alveoli, an inflammatory infiltrate with a mixed cell type, and increased macrophages in the high-dose rats. Tissue

  7. Gold Nanoparticles Obtained by Bio-precipitation from Gold(III) Solutions

    International Nuclear Information System (INIS)

    Gardea-Torresdey, J.L.; Tiemann, K.J.; Gamez, G.; Dokken, K.; Tehuacanero, S.; Jose-Yacaman, M.

    1999-01-01

    The use of metal nanoparticles has shown to be very important in recent industrial applications. Currently gold nanoparticles are being produced by physical methods such as evaporation. Biological processes may be an alternative to physical methods for the production of gold nanoparticles. Alfalfa biomass has shown to be effective at passively binding and reducing gold from solutions containing gold(III) ions and resulting in the formation of gold(0) nanoparticles. High resolution microscopy has shown that five different types of gold particles are present after reaction with gold(III) ions with alfalfa biomass. These particles include: fcc tetrahedral, hexagonal platelet, icosahedral multiple twinned, decahedral multiple twinned, and irregular shaped particles. Further analysis on the frequency of distribution has shown that icosahedral and irregular particles are more frequently formed. In addition, the larger particles observed may be formed through the coalescence of smaller particles. Through modification of the chemical parameters, more uniform particle size distribution may be obtained by the alfalfa bio-reduction of gold(III) from solution

  8. Gold and gold-copper nanoparticles in 2-propanol: A radiation chemical study

    International Nuclear Information System (INIS)

    Dey, G.R.

    2011-01-01

    The studies on the reduction of Au 3+ to gold nanoparticles in presence and absence of Cu 2+ under deoxygenated conditions in 2-propanol by radiolytic method have been carried out. On γ-radiolysis, preliminary yellow colored solution of Au 3+ changed to purple color owing to gold nanoparticles formation, which exhibits an absorption peak at around 540 nm. In the presence of Cu 2+ , absorption of gold-copper nanoparticles, which was also produced during γ-radiolysis, was red shifted in contrast to the system containing no Cu 2+ . Under DLS studies the sizes of gold nanoparticles in the absence and the presence of Cu 2+ were found to be larger (>400 nm). However, in presence of polyethylene glycol, a stabilizer the nanoparticle sizes became smaller, sizes measured for gold and gold-copper nanoparticles are 40 and 140 nm, respectively. Moreover, the change in UV-vis spectra in the Cu 2+ and Au 3+ mixed system highlights the formation of gold-copper nanoparticles in core-shell type arrangement. - Highlights: → Present radiation chemical study highlights high reactivity of Au ·2+ with Cu 2+ . → Absorption of gold-copper nanoparticles is blue shifted as compared to copper nanoparticles. → Change in UV-vis spectra with dose emphasizes core-shell type arrangement of Au-Cu nanoparticles.

  9. Knowledge-driven GIS modeling technique for gold exploration, Bulghah gold mine area, Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Ahmed A. Madani

    2011-12-01

    Full Text Available This research aims to generate a favorability map for gold exploration at the Bulghah gold mine area using integration of geo-datasets within a GIS environment. Spatial data analyses and integration of different geo-datasets are carried out based on knowledge-driven and weighting technique. The integration process involves the weighting and scoring of different layers affecting the gold mineralization at the study area using the index overlay method within PCI Geomatica environment. Generation of the binary predictor maps for lithology, lineaments, faults and favorable contacts precede the construction of the favorability map. About 100 m buffer zones are generated for favorable contacts, lineaments and major faults layers. Internal weighting is assigned to each layer based on favorability for gold mineralization. The scores for lithology, major faults, lineaments and favorable contacts layers in the constructed favorability map are 50%, 25%, 10% and 15%, respectively. Final favorability map for the Bulghah gold mine area shows the recording of two new sites for gold mineralization located at the northern and southern extensions of tonalite–diorite intrusions. The northern new site is now exploited for gold from the Bulghah North mine. The southern new site is narrow and small; its rocks resemble those of the Bulghah gold mine.

  10. Genesis of uranium-gold pyritic conglomerates

    International Nuclear Information System (INIS)

    Myers, W.B.

    1981-01-01

    The ancient pyritic ore conglomerates have a common origin best exemplified by the Witwatersrand deposits. All contain detrital pyrite and uraninite, which are unstable in modern oxygenated environments and were deposited in a reducing atmosphere. The Rand reefs are not similar to modern gold placers. Placers result from the near incapacity of streams and currents to transport coarse gold. Placers as rich as Rand reef occur only in narrow paystreaks within 15 kilometers of a coarse-gold source. The board dispersion of gold in the reefs is due to solution transport of metal complexed as aurous sulfide, leached anoxygenically from crustal rocks, probably from sea-floor basalt, and precipitated by a slow reaction driven by the radioactive decay of detrital uraninite. Radiolysis of water on shallow marine unconformities resulted in diffusion of hydrogen to the atmosphere and a slight excess of hydroxyl free radical in the reef environment. The mild oxidizing tendency slowly dissolved uranium, precipitated gold, and oxygenated thucholite. These actions define a maturing process. A uraninite placer accumulating on an unconformity becomes progressively converted to a gold reef with little residual uraninite. The most mature reefs tend to grade toward the thucholite-seam type, very thin but exceedingly rich in gold. A combination of chemical attack and physical reworking accounts for the general thinness of mature reefs. Pyrite, like uraninite, decreases in abundance with increasing maturity; buffering by pyrite moderated the oxidative depletion of uranium. Where pyrite was scanty or absent, uraninite was completely dissolved by the effects of radiolysis and no ore formed

  11. Beneficiation of the gold bearing ore by gravity and flotation

    Science.gov (United States)

    Gül, Alim; Kangal, Olgaç; Sirkeci, Ayhan A.; Önal, Güven

    2012-02-01

    Gold concentration usually consists of gravity separation, flotation, cyanidation, or the combination of these processes. The choice among these processes depends on the mineralogical characterization and gold content of the ore. Recently, the recovery of gold using gravity methods has gained attention because of low cost and environmentally friendly operations. In this study, gold pre-concentrates were produced by the stepwise gravity separation and flotation techniques. The Knelson concentrator and conventional flotation were employed for the recovery of gold. Gold bearing ore samples were taken from Gümüşhane Region, northern east part of Turkey. As a result of stepwise Knelson concentration experiments, a gold concentrate assaying around 620 g/t is produced with 41.4wt% recovery. On the other hand, a gold concentrate about 82 g/t is obtained with 89.9wt% recovery from a gold ore assaying 6 g/t Au by direct flotation.

  12. Gold leaf counter electrodes for dye-sensitized solar cells

    Science.gov (United States)

    Shimada, Kazuhiro; Toyoda, Takeshi

    2018-03-01

    In this study, a gold leaf 100 nm thin film is used as the counter electrode in dye-sensitized solar cells. The traditional method of hammering gold foil to obtain a thin gold leaf, which requires only small amounts of gold, was employed. The gold leaf was then attached to the substrate using an adhesive to produce the gold electrode. The proposed approach for fabricating counter electrodes is demonstrated to be facile and cost-effective, as opposed to existing techniques. Compared with electrodes prepared with gold foil and sputtered gold, the gold leaf counter electrode demonstrates higher catalytic activity with a cobalt-complex electrolyte and higher cell efficiency. The origin of the improved performance was investigated by surface morphology examination (scanning electron microscopy), various electrochemical analyses (cyclic voltammetry, linear sweep voltammetry, and electrochemical impedance spectroscopy), and crystalline analysis (X-ray diffractometry).

  13. Moessbauer study of the chemical state of gold in gold ores

    International Nuclear Information System (INIS)

    Wagner, F.E.; Marion, P.H.; Regnard, J.-R.

    1986-01-01

    Information on the chemical state of gold in gold ores has been obtained by 197 Au Moessbauer spectroscopy in cases where the state of this element cannot be determined by such standard methods as optical or electron microscopy. Ore concentrates consisting mainly of pyrite or arsenopyrite and roasted ore and matte samples were studied. The results yielded directly the respective amounts of metallic and chemically bound gold. Unless the gold is metallic, its chemical state in the ores turns out to be different from that in the minerals studied so far as reference materials. The chemical processes taking place during various treatments of the ores, such as roasting or leaching, can also be followed by Moessbauer spectroscopy. It is hoped that Moessbauer spectroscopy will eventually facilitate the development of more efficient methods of gold extraction

  14. Oxidation state of gold and arsenic in gold-bearing arsenian pyrite

    Energy Technology Data Exchange (ETDEWEB)

    Simon, G.; Huang, H.; Penner-Hahn, J.E.; Kesler, S.E.; Kao, L.S. [Univ. of Michigan, Ann Arbor, MI (United States)

    1999-07-01

    XANES measurements on gold-bearing arsenian pyrite from the Twin Creeks Carlin-type gold deposits show that gold is present as both Au{sup 0} and Au{sup 1+} and arsenic is present as As{sup 1{minus}}. Au{sup 0} is attributed to sub-micrometer size inclusions of free gold, whereas Au{sup 1+} is attributed to gold in the lattice of the arsenian pyrite. STEM observations suggest that As{sup 1{minus}} is probably concentrated in angstrom-scale, randomly distributed layers with a marcasite or arsenopyrite structure. Ionic gold (Au{sup 1+}) could be concentrated in these layers as well, and is present in both twofold- and fourfold-coordinated forms, with fourfold-coordinated Au{sup 1+} more abundant. Twofold-coordinated Au{sup 1+} is similar to gold in Au{sub 2}S in which it is linearly coordinated to two sulfur atoms. The nature of fourfold-coordinated Au{sup 1+} is not well understood, although it might be present as an Au-As-S compound where gold is bonded in fourfold coordination to sulfur and arsenic atoms, or in vacancy positions on a cation site in the arsenian pyrite. Au{sup 1+} was probably incorporated into arsenian pyrite by adsorption onto pyrite surfaces during crystal growth. The most likely compound in the case of twofold-coordinated Au{sup 1+} was probably a tri-atomic surface complex such as S{sub pyrite}-Au{sup 1+}-S{sub bi-sulfide}H or Au{sup 1+}-S-Au{sup 1+}. The correlation between gold and arsenic might be related to the role of arsenic in enhancing the adsorption of gold complexes of this type on pyrite surfaces, possibly through semiconductor effects.

  15. Silver, gold, and alloyed silver-gold nanoparticles: characterization and comparative cell-biologic action

    Energy Technology Data Exchange (ETDEWEB)

    Mahl, Dirk; Diendorf, Joerg; Ristig, Simon [University of Duisburg-Essen, Department of Inorganic Chemistry, Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany); Greulich, Christina [Ruhr-University of Bochum, Bergmannsheil University Hospital/Surgical Research (Germany); Li Zian; Farle, Michael [University of Duisburg-Essen, Faculty of Physics, Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany); Koeller, Manfred [Ruhr-University of Bochum, Bergmannsheil University Hospital/Surgical Research (Germany); Epple, Matthias, E-mail: matthias.epple@uni-due.de [University of Duisburg-Essen, Department of Inorganic Chemistry, Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany)

    2012-10-15

    Silver, gold, and silver-gold-alloy nanoparticles were prepared by citrate reduction modified by the addition of tannin during the synthesis, leading to a reduction in particle size by a factor of three. Nanoparticles can be prepared by this easy water-based synthesis and subsequently functionalized by the addition of either tris(3-sulfonatophenyl)phosphine or poly(N-vinylpyrrolidone). The resulting nanoparticles of silver (diameter 15-25 nm), gold (5-6 nm), and silver-gold (50:50; 10-12 nm) were easily dispersable in water and also in cell culture media (RPMI + 10 % fetal calf serum), as shown by nanoparticle tracking analysis and differential centrifugal sedimentation. High-resolution transmission electron microscopy showed a polycrystalline nature of all nanoparticles. EDX on single silver-gold nanoparticles indicated that the concentration of gold is higher inside a nanoparticle. The biologic action of the nanoparticles toward human mesenchymal stem cells (hMSC) was different: Silver nanoparticles showed a significant concentration-dependent influence on the viability of hMSC. Gold nanoparticles showed only a small effect on the viability of hMSC after 7 days. Surprisingly, silver-gold nanoparticles had no significant influence on the viability of hMSC despite the silver content. Silver nanoparticles and silver-gold nanoparticles in the concentration range of 5-20 {mu}g mL{sup -1} induced the activation of hMSC as indicated by the release of IL-8. In contrast, gold nanoparticles led to a reduction of the release of IL-6 and IL-8.

  16. Silver, gold, and alloyed silver-gold nanoparticles: characterization and comparative cell-biologic action

    Science.gov (United States)

    Mahl, Dirk; Diendorf, Jörg; Ristig, Simon; Greulich, Christina; Li, Zi-An; Farle, Michael; Köller, Manfred; Epple, Matthias

    2012-10-01

    Silver, gold, and silver-gold-alloy nanoparticles were prepared by citrate reduction modified by the addition of tannin during the synthesis, leading to a reduction in particle size by a factor of three. Nanoparticles can be prepared by this easy water-based synthesis and subsequently functionalized by the addition of either tris(3-sulfonatophenyl)phosphine or poly( N-vinylpyrrolidone). The resulting nanoparticles of silver (diameter 15-25 nm), gold (5-6 nm), and silver-gold (50:50; 10-12 nm) were easily dispersable in water and also in cell culture media (RPMI + 10 % fetal calf serum), as shown by nanoparticle tracking analysis and differential centrifugal sedimentation. High-resolution transmission electron microscopy showed a polycrystalline nature of all nanoparticles. EDX on single silver-gold nanoparticles indicated that the concentration of gold is higher inside a nanoparticle. The biologic action of the nanoparticles toward human mesenchymal stem cells (hMSC) was different: Silver nanoparticles showed a significant concentration-dependent influence on the viability of hMSC. Gold nanoparticles showed only a small effect on the viability of hMSC after 7 days. Surprisingly, silver-gold nanoparticles had no significant influence on the viability of hMSC despite the silver content. Silver nanoparticles and silver-gold nanoparticles in the concentration range of 5-20 μg mL-1 induced the activation of hMSC as indicated by the release of IL-8. In contrast, gold nanoparticles led to a reduction of the release of IL-6 and IL-8.

  17. Silver, gold, and alloyed silver–gold nanoparticles: characterization and comparative cell-biologic action

    International Nuclear Information System (INIS)

    Mahl, Dirk; Diendorf, Jörg; Ristig, Simon; Greulich, Christina; Li Zian; Farle, Michael; Köller, Manfred; Epple, Matthias

    2012-01-01

    Silver, gold, and silver–gold-alloy nanoparticles were prepared by citrate reduction modified by the addition of tannin during the synthesis, leading to a reduction in particle size by a factor of three. Nanoparticles can be prepared by this easy water-based synthesis and subsequently functionalized by the addition of either tris(3-sulfonatophenyl)phosphine or poly(N-vinylpyrrolidone). The resulting nanoparticles of silver (diameter 15–25 nm), gold (5–6 nm), and silver–gold (50:50; 10–12 nm) were easily dispersable in water and also in cell culture media (RPMI + 10 % fetal calf serum), as shown by nanoparticle tracking analysis and differential centrifugal sedimentation. High-resolution transmission electron microscopy showed a polycrystalline nature of all nanoparticles. EDX on single silver–gold nanoparticles indicated that the concentration of gold is higher inside a nanoparticle. The biologic action of the nanoparticles toward human mesenchymal stem cells (hMSC) was different: Silver nanoparticles showed a significant concentration-dependent influence on the viability of hMSC. Gold nanoparticles showed only a small effect on the viability of hMSC after 7 days. Surprisingly, silver–gold nanoparticles had no significant influence on the viability of hMSC despite the silver content. Silver nanoparticles and silver–gold nanoparticles in the concentration range of 5–20 μg mL −1 induced the activation of hMSC as indicated by the release of IL-8. In contrast, gold nanoparticles led to a reduction of the release of IL-6 and IL-8.

  18. Contributions to a systematic examination of deformed transition nuclei by the study of the decay of 188Tl and 190Tl

    International Nuclear Information System (INIS)

    Waetzig, W.

    1980-01-01

    Using the reaction 197 Au( 3 He,xn) Tl the decay of the nuclides 188 Tl and 190 Tl to 188 Hg (Tsub(1/2) = 70s) respectively to 190 Hg(Tsub(1/2) = 3.0 min) was studied at the mass separator ISOCELE of the Orsay-synchrocyclotron by gamma, conversion electron, gamma-gamma coincidence, and electron-gamma coincidence spectroscopy. The level schemes of 188 Hg and 190 Hg could be remarkably extended in comparison with earlier works. By a statistical analysis of the nuclear level density the nuclear temperature was calculated as a measure for the number of excitation modes of these nuclei. (orig./HSI) [de

  19. Authentication of gold products by nuclear methods

    International Nuclear Information System (INIS)

    De Jesus, A.S.M.

    1985-01-01

    The falsification of valuable gold items is a threat to the authenticity of gold products. To solve this, there is a continuous search for reliable, practicle and cost-effective means of identifying forgeries. Because nuclear techniques as applied to elemental analysis have a high degree of specificity, are non-destructive and permit the availability of results within a relatively short time, a few of these techniques were investigated and reviewed in the article. Work on some promising methods in the author's laboratory is also discussed. Constraints such as those imposed by the time taken by the measurement, negligible residual activity within a relatively short time were also considered. The techniques that were investigated include: the transmission of electromagnetic radiation through a medium; scattering of electromagnetic radiation; x-ray fluorescence analysis; neutron activation analysis; activation by the inelastic scattering of gamma radiation; activation by the inelastic scattering of fast neutrons; absorption and scattering of fast neutrons; self-attenuation of gamma radiation. The shape of the object being investigated, should also be considered. It is concluded that a system based on the inelastic scattering of neutrons emitted by a 241 Am/Be source (halflife = 433 years) is practical and capable of authenticating gold and gold alloy coins such as Krugerrands. The feasibility study on the assaying of gold jewelry by means of nuclear methods also showed it to be impractical

  20. Gold nanoparticle-based electrochemical biosensors

    Energy Technology Data Exchange (ETDEWEB)

    Pingarron, Jose M.; Yanez-Sedeno, Paloma; Gonzalez-Cortes, Araceli [Department of Analytical Chemistry, Faculty of Chemistry, University Complutense of Madrid, 28040 Madrid (Spain)

    2008-08-01

    The unique properties of gold nanoparticles to provide a suitable microenvironment for biomolecules immobilization retaining their biological activity, and to facilitate electron transfer between the immobilized proteins and electrode surfaces, have led to an intensive use of this nanomaterial for the construction of electrochemical biosensors with enhanced analytical performance with respect to other biosensor designs. Recent advances in this field are reviewed in this article. The advantageous operational characteristics of the biosensing devices designed making use of gold nanoparticles are highlighted with respect to non-nanostructured biosensors and some illustrative examples are commented. Electrochemical enzyme biosensors including those using hybrid materials with carbon nanotubes and polymers, sol-gel matrices, and layer-by-layer architectures are considered. Moreover, electrochemical immunosensors in which gold nanoparticles play a crucial role in the electrode transduction enhancement of the affinity reaction as well as in the efficiency of immunoreagents immobilization in a stable mode are reviewed. Similarly, recent advances in the development of DNA biosensors using gold nanoparticles to improve DNA immobilization on electrode surfaces and as suitable labels to improve detection of hybridization events are considered. Finally, other biosensors designed with gold nanoparticles oriented to electrically contact redox enzymes to electrodes by a reconstitution process and to the study of direct electron transfer between redox proteins and electrode surfaces have also been treated. (author)

  1. Gold Nanoparticle Labels Amplify Ellipsometric Signals

    Science.gov (United States)

    Venkatasubbarao, Srivatsa

    2008-01-01

    The ellipsometric method reported in the immediately preceding article was developed in conjunction with a method of using gold nanoparticles as labels on biomolecules that one seeks to detect. The purpose of the labeling is to exploit the optical properties of the gold nanoparticles in order to amplify the measurable ellipsometric effects and thereby to enable ultrasensitive detection of the labeled biomolecules without need to develop more-complex ellipsometric instrumentation. The colorimetric, polarization, light-scattering, and other optical properties of nanoparticles depend on their sizes and shapes. In the present method, these size-and-shape-dependent properties are used to magnify the polarization of scattered light and the diattenuation and retardance of signals derived from ellipsometry. The size-and-shape-dependent optical properties of the nanoparticles make it possible to interrogate the nanoparticles by use of light of various wavelengths, as appropriate, to optimally detect particles of a specific type at high sensitivity. Hence, by incorporating gold nanoparticles bound to biomolecules as primary or secondary labels, the performance of ellipsometry as a means of detecting the biomolecules can be improved. The use of gold nanoparticles as labels in ellipsometry has been found to afford sensitivity that equals or exceeds the sensitivity achieved by use of fluorescence-based methods. Potential applications for ellipsometric detection of gold nanoparticle-labeled biomolecules include monitoring molecules of interest in biological samples, in-vitro diagnostics, process monitoring, general environmental monitoring, and detection of biohazards.

  2. Gold nanoparticle-based electrochemical biosensors

    International Nuclear Information System (INIS)

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

    2008-01-01

    The unique properties of gold nanoparticles to provide a suitable microenvironment for biomolecules immobilization retaining their biological activity, and to facilitate electron transfer between the immobilized proteins and electrode surfaces, have led to an intensive use of this nanomaterial for the construction of electrochemical biosensors with enhanced analytical performance with respect to other biosensor designs. Recent advances in this field are reviewed in this article. The advantageous operational characteristics of the biosensing devices designed making use of gold nanoparticles are highlighted with respect to non-nanostructured biosensors and some illustrative examples are commented. Electrochemical enzyme biosensors including those using hybrid materials with carbon nanotubes and polymers, sol-gel matrices, and layer-by-layer architectures are considered. Moreover, electrochemical immunosensors in which gold nanoparticles play a crucial role in the electrode transduction enhancement of the affinity reaction as well as in the efficiency of immunoreagents immobilization in a stable mode are reviewed. Similarly, recent advances in the development of DNA biosensors using gold nanoparticles to improve DNA immobilization on electrode surfaces and as suitable labels to improve detection of hybridization events are considered. Finally, other biosensors designed with gold nanoparticles oriented to electrically contact redox enzymes to electrodes by a reconstitution process and to the study of direct electron transfer between redox proteins and electrode surfaces have also been treated

  3. Gold prices: Analyzing its cyclical behavior

    Directory of Open Access Journals (Sweden)

    Martha Gutiérrez

    2013-07-01

    Full Text Available Gold is a commodity that is seen as a safe haven when a financial crisis strikes, but when stock markets are prosperous, these are more attractive investment alternatives, and so the gold cycle goes on and on. The DJIA/GF (Dow Jones Industrial Average and Gold Fix ratio is chosen to establish the evolution of gold prices in relation to the NYSE. This paper has two goals: to prove that the DJIA/GF ratio is strongly cyclical by using Fourier analysis and to set a predictive neural networks model to forecast the behavior of this ratio during 2011-2020. To this end, business cycle events like the Great Depression along with the 1970s crisis, and the 1950s boom along with the world economic recovery of the 1990s are contrasted in light of the mentioned ratio. Gold prices are found to evolve cyclically with a dominant period of 37 years and are mainly affected by energy prices, financial markets and macroeconomic indicators.

  4. The Complete Reconfiguration of Dendritic Gold

    Science.gov (United States)

    Paneru, Govind; Flanders, Bret

    2014-03-01

    Reconfigurability-by-design is an important strategy in modern materials science, as materials with this capability could potentially be used to confer hydrophobic, lipophobic, or anti-corrosive character to substrates in a regenerative manner. The present work extends the directed electrochemical nanowire assembly (DENA) methodology, which is a technique that employs alternating voltages to grow single crystalline metallic nanowires and nano-dendrites from simple salt solutions, to enable the complete dissolution of macroscopic arrays of metallic dendrites following their growth. Our main finding is that structural reconfiguration of dendritic gold is induced by changes in the MHz-level frequencies of voltages that are applied to the dendrites. Cyclic voltammetry and micro-Raman spectroscopy have been used to show that dendritic gold grows and dissolves by the same chemical mechanisms as bulk gold. Hence, the redox chemistry that occurs at the crystal-solution interface is no different than the established electrochemistry of gold. What differs in this process and allows for reconfiguration to occur is the diffusive behavior of the gold chloride molecules in the solution adjacent to the interface. We will present a simple model that captures the physics of this behavior.

  5. Radiofrequency Heating Pathways for Gold Nanoparticles

    Science.gov (United States)

    Collins, C. B.; McCoy, R. S.; Ackerson, B. J.; Collins, G. J.

    2015-01-01

    This feature article reviews the thermal dissipation of nanoscopic gold under radiofrequency (RF) irradiation. It also presents previously unpublished data addressing obscure aspects of this phenomenon. While applications in biology motivated initial investigation of RF heating of gold nanoparticles, recent controversy concerning whether thermal effects can be attributed to nanoscopic gold highlight the need to understand the involved mechanism or mechanisms of heating. Both the nature of the particle and the nature of the RF field influence heating. Aspects of nanoparticle chemistry and physics, including the hydrodynamic diameter of the particle, the oxidation state and related magnetism of the core, and the chemical nature of the ligand shell may all strongly influence to what extent a nanoparticle heats in an RF field. Aspects of RF include: power, frequency and antenna designs that emphasize relative strength of magnetic or electric fields, and also influence the extent to which a gold nanoparticle heats in RF. These nanoparticle and RF properties are analysed in the context of three heating mechanisms proposed to explain gold nanoparticle heating in an RF field. This article also makes a critical analysis of the existing literature in the context of the nanoparticle preparations, RF structure, and suggested mechanisms in previously reported experiments. PMID:24962620

  6. Simple fabrication of gold nanobelts and patterns.

    Directory of Open Access Journals (Sweden)

    Renyun Zhang

    Full Text Available Gold nanobelts are of interest in several areas; however, there are only few methods available to produce these belts. We report here on a simple evaporation induced self-assembly (EISA method to produce porous gold nanobelts with dimensions that scale across nanometer (thickness ∼80 nm and micrometer (width ∼20 µm, to decimeter (length ∼0.15 m. The gold nanobelts are well packed on the beaker wall and can be easily made to float on the surface of the solution for depositing onto other substrates. Microscopy showed that gold nanobelts had a different structure on the two sides of the belt; the density of gold nanowires on one side was greater than on the other side. Electrical measurements showed that these nanobelts were sensitive to compressive or tensile forces, indicating a potential use as a strain sensor. The patterned nanobelts were further used as a template to grow ZnO nanowires for potential use in applications such as piezo-electronics.

  7. Precipitation of lamellar gold nanocrystals in molten polymers

    International Nuclear Information System (INIS)

    Palomba, M.; Carotenuto, G.

    2016-01-01

    Non-aggregated lamellar gold crystals with regular shape (triangles, squares, pentagons, etc.) have been produced by thermal decomposition of gold chloride (AuCl) molecules in molten amorphous polymers (polystyrene and poly(methyl methacrylate)). Such covalent inorganic gold salt is high soluble into non-polar polymers and it thermally decomposes at temperatures compatible with the polymer thermal stability, producing gold atoms and chlorine radicals. At the end of the gold precipitation process, the polymer matrix resulted chemically modified because of the partial cross-linking process due to the gold atom formation reaction.

  8. Photoreduction of Carbon Dioxide to Methane Over Sb1.5Sn8.5-x Ti x O19.0 with High Conductivity.

    Science.gov (United States)

    Do, Jeong Yeon; Kwak, Byeong Sub; Kang, Misook

    2018-09-01

    In order to enhance the photoreduction of CO2 to CH4, a new type of photocatalyst, Sb1.5Sn8.5-xTixO19.0, with high conductivity and low bandgap was developed by partially incorporating Ti into the framework of Sb1.5Sn8.5O19.0 (antimony-doped tin oxide, ATO) using a controlled hydrothermal method. XRD and TEM analyses indicated that the Sb1.5Sn8.5-xTixO19.0 particles exhibited a tetragonal crystal structure and were approximately 20 nm in size. Furthermore, the bandgap and conductivity of these materials increased with increasing Ti content. A study of the photoreduction of CO2 with H2O revealed a remarkable increase in the generation of CH4 over the Sb1.5Sn8.5-xTixO19.0 catalysts. In particular, CH4 generation was the highest when Sb1.5Sn8.5Ti1.0O19.0 was used as the photocatalyst, and was three-fold higher than that achieved by using anatase TiO2. Photoluminescence studies showed that the enhanced photocatalytic activity of the Sb1.5Sn8.5-xTixO19.0 materials could be attributed to the interfacial transfer of photogenerated charges, which led to an effective charge separation and inhibition of the recombination of photogenerated electron-hole (e-/h+) pairs.

  9. Gold grade variation and particle microchemistry in exploration pits of the Batouri gold district, SE Cameroon

    Science.gov (United States)

    Vishiti, A.; Suh, C. E.; Lehmann, B.; Egbe, J. A.; Shemang, E. M.

    2015-11-01

    The Batouri area hosts lode-gold mineralization under several-m-thick lateritic cover. Pitting to bed rock on a geochemical Au anomaly defined from previous reconnaissance soil sampling identified five horizons ranging from saprock at the base to laterite at the top. Analysis of bulk samples from each horizon by fire assay shows that most of the horizons are barren although 119 ppb and 48 ppb Au values were obtained from one laterite horizon and one saprolite horizon, respectively, from two separate pits. All the horizons were panned and particulate gold was also recovered only from these two horizons. The gold grains from both horizons are morphologically and compositionally indistinguishable with rare quartz, pyrite and galena inclusions. The grains have irregular, sub-rounded, bean to elongated shapes and they show a remarkable core-rim zonation. Electron microprobe analysis of the grains recorded high gold content in the rims (86.3-100 wt%) and along fissures within the grains (95.1-100 wt%). The cores are relatively Ag rich (11.8-14 wt% Ag) while the rims (0.63-13.7 wt% Ag, most of the values fall within the lower limit of this range) and fissures (0.03-5.02 wt% Ag) are poor in Ag. The low Ag concentration in the rims and along fissures is attributed to preferential leaching of Ag; a process recognized in gold grains and platiniferous alloys from alluvia. The core composition of the grains is similar to that of primary gold composition in the bedrock. These results show that gold in the soil is relic particulate gold derived from the primary source with no evidence of secondary gold precipitation in the weathering cycle. In all the pits no horizon was systematically enriched in gold suggesting there has been no chemical remobilization of gold in this environment. Rather the dispersion of gold here is in the particulate form. Therefore combining particulate gold features with assay data is relevant to exploration in such tropical environments.

  10. Geomicrobial Optical Logging Detectors (GOLD)

    Science.gov (United States)

    Bramall, N. E.; Stoker, C. R.; Price, P. B.; Coates, J. D.; Allamandola, L. J.; Mattioda, A. L.

    2008-12-01

    to in situ processes. 4) Temperature and Oxygen Sensors: The ambient temperature will be recorded as well as the presence of oxygen. Oxygen presence can be measured using a fluorescence quenching fiber optic probe to avoid interference from other gases. We forsee that this technology will enable experiments including studies of gene transfer, microbial habitat, in situ stratigraphy and hydrological processes. In addition, though designed to scan borehole walls, GOLD could be used to scan core samples as they are recovered for rapid quantification and analysis in order to discover samples of particular interest that could then be prioritized for more in-depth, traditional analysis.

  11. Purification, isolation, crystallization, and preliminary X-ray diffraction study of the BTB domain of the centrosomal protein 190 from Drosophila melanogaster

    Science.gov (United States)

    Boyko, K. M.; Nikolaeva, A. Yu.; Kachalova, G. S.; Bonchuk, A. N.; Popov, V. O.

    2017-11-01

    The spatial organization of the genome is controlled by a special class of architectural proteins, including proteins containing BTB domains that are able to dimerize or multimerize. The centrosomal protein 190 is one of such architectural proteins. The purification, crystallization, and preliminary X-ray diffraction study of the BTB domain of the centrosomal protein 190 are reported. The crystallization conditions were found by the vapor-diffusion technique. The crystals diffracted to 1.5 Å resolution and belonged to sp. gr. P3221. The structure was solved by the molecular replacement method. The structure refinement is currently underway.

  12. Lime in gold and uranium mining

    International Nuclear Information System (INIS)

    Van Staden, C.M.

    1979-01-01

    In this article the author discusses the role of lime in gold and uranium extraction and looks more closely at the industry's efforts to improve the environment by vegetation of sand dumps and slimes dams. He then comes to the conclusion that lime has been and still is the most effective, practical and cheapest chemical that can be used in the South African gold and uranium mining industry to settle pulps, protect cyanide solutions, aid the vegetation of dumps and neutralise acidic waters and residues. The gold and uranium industry is very pollution concious, and in South Africa the importance of the role that lime plays in combating air and water pollution cannot be over emphasised

  13. Cancer nanotechnology: emerging role of gold nanoconjugates.

    Science.gov (United States)

    Kudgus, Rachel A; Bhattacharya, Resham; Mukherjee, Priyabrata

    2011-12-01

    Over the last few decades, the study of nanotechnology has grown exponentially. Nanotechnology bridges science, engineering and technology; it continues to expand in definition as well as practice. One sub-set of nanotechnology is bionanotechnology, this will be the focus of this review. Currently, bionanotechnology is being studied and exploited for utility within medicinal imaging, diagnosis and therapy in regard to cancer. Cancer is a world-wide health problem and the implication rate as well as the death rate increase year to year. However promising work is being done with gold nanoparticles for detection, diagnosis and targeted drug delivery therapy. Gold nanoparticles can be synthesized in various shapes and sizes, which directly correlates to the color; they can also be manipulated to carry various antibody, protein, plasmid, DNA or small molecule drug. Herein we summarize some of the very influential research being done in the field of Cancer Nanotechnology with an emphasis on gold nanoparticles.

  14. Gold Nanospheres Dispersed Light Responsive Epoxy Vitrimers

    Directory of Open Access Journals (Sweden)

    Zhenhua Wang

    2018-01-01

    Full Text Available Vitrimers represent a new class of smart materials. They are covalently crosslinked like thermosets, yet they can be reprocessed like thermoplastics. The underlying mechanism is the rapid exchange reactions which form new bonds while breaking the old ones. So far, heating is the most widely used stimulus to activate the exchange reaction. Compared to heating, light not only is much more convenient to achieve remote and regional control, but can also offer fast healing. Gold nanospheres are excellent photothermal agents, but they are difficult to disperse into vitrimers as they easily aggregate. In this paper, we use polydopamine to prepare gold nanospheres. The resultant polydopamine-coated gold nanospheres (GNS can be well dispersed into epoxy vitrimers, endowing epoxy vitrimers with light responsivity. The composites can be reshaped permanently and temporarily with light at different intensity. Efficient surface patterning and healing are also demonstrated.

  15. Optical constant of thin gold films

    DEFF Research Database (Denmark)

    Yakubovsky, D. I.; Fedyanin, D. Yu; Arsenin, A. V.

    2017-01-01

    The performance of metal-based devices is limited by ohmic losses in the metal, which are determined by electron scattering. The structural properties of gold thin films also play an important role in the film quality, which may affect its' optical properties and the overall capability...... and spectroscopic ellipsometry, the structural morphology and optical properties of polycrystalline gold thin films (fabricated by e-beam deposition at a low sputtering rate smooth gold) in the thickness range of 20 - 200 nm. By extracting the real and imaginary dielectric function and the Drude parameter...... of the device. At the same time, metal films of different thicknesses are needed for different applications and, since these films are polycrystalline, their internal properties and surface roughness can greatly vary from one thickness to another. In this work, we study, using atomic force microscopy...

  16. Microbially Induced Precipitation of Gold(0) Nanoparticles.

    Science.gov (United States)

    Roh, Yu; Kang, Serku; Park, Bitna; Kim, Yumi

    2015-01-01

    The objectives of this study were to synthesize gold nanoparticles by biomineralization using metal-reducing bacteria and to characterize their mineralogical properties. The metal-reducing bacteria were able to reduce Au(III) to Au(0) with organic fatty acids as electron donors, as indicated by the color change of the culture solution from colorless gold ions to black precipitates at 25 degrees C. XRD, SEM- and TEM-EDS analyses of the precipitates showed that Au(0) was precipitated and formed at either the cell membrane or extracellularly. The Au(0) nanoparticles were about 200 nm in size and ball-shaped. Biomineralization for elemental Au(0) nanoparticle synthesis may be useful for the recovery of natural gold in natural environments.

  17. Preparation of radioactive colloidal gold 198Au

    International Nuclear Information System (INIS)

    Cammarosano, S.A.

    1979-01-01

    The preparation with simple equipment of radioactive colloidal gold of particle size about approximately 300 A from seed colloid stabilized by gelatine is described. Some physico-chemical parameters which can affect the process of formation of these colloidal particles are analysed; particle size has been meassured with an electron microscope. The colloid stability has been studied as a function of dilution, age and pH. Nucleation and growth of radioactive colloidal gold have been studied using spectrophotometry. Absorption spectra of the two ones are presented and compared. Quality control of the production process is verified through measurement of parameters, such as radioactive and radiochemical purity and biological distribution in laboratorial animals. This distribution was evalusted for rats injected endovenously with the gold colloidal solution.(Author) [pt

  18. Free gold recovery by coal-oil agglomeration

    Energy Technology Data Exchange (ETDEWEB)

    Kotze, W.; Petersen, F.W. [Cape Technikon Cape Town (South Africa). Dept. of Chemical Engineering

    2000-02-01

    The gold mining industry has mainly relied upon the use of highly polluting chemicals, such as mercury and cyanide to recover gold from its ores. The Coal Gold Agglomeration (CGA) process was developed some years ago and has the advantage in that gold is recovered by a procedure which has little or no negative impact on the environment. A gold ore containing liberated gold particles is contacted with coal-oil agglomerates, whereby the gold is recovered into the coal/oil phase. Laboratory scale batch tests were performed on an artificial mixture gold slurry and gold recoveries of up to 85% were found under optimized conditions. By recycling the coal/oil phase, it was found that the gold loading onto the agglomerates was increased. Tests performed on an industrial ore yielded slightly lower gold recoveries, and X-ray Diffraction (XRD) analysis on the coal/oil phase showed that minerals other than gold were recovered into this phase. A comparative study was conducted whereby the CGA process was compared to mercury amalgamation. Gold recoveries obtained through amalgamation were 15% lower than by the agglomeration process, which indicates that this process can be considered favourably as an alternative to amalgamation. 16 refs., 2 figs., 6 tabs.

  19. Size fraction assaying of gold bearing rocks (for gold extraction) by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Ahmed, K.; Dampare, S.B.; Addo, M.A.; Osae, S.; Adotey, D.K.; Adomako, D.

    2005-01-01

    A novel method has been developed for processing and extraction of gold from gold bearing rocks for use by small-scale gold miners in Ghana. The methodology involved crushing of gold bearing hard rocks to fine particles to form a composite sample and screening at a range of sizes. Gold distribution in the composite sample was determined as a function of particle size by using Instrumental Neutron Activation Analysis. The concentrations of gold for the corresponding particle sizes were 16.4 ± 0.17mg/kg for sizes <63μm; 161± 0.75 mg/kg for 63 - 125 μm, 0.53 + 0.03 mg/kg for 125 - 250 μm, 4.66± 0.07 mg/kg for 250 - 355 μm, 1.55 ± 0.06 for 355 - 425 μm, 0.80 ± 0.008 mg/kg for 425 -1000 μm, and 1.27 + 0.05 mg/kg for 1000-2000 μm. The average gold content in a 7.127 kg composite sample based on particle size found to be 3.08 mg/kg. (au)

  20. Major Brazilian gold deposits - 1982 to 1999

    Science.gov (United States)

    Thorman, Charles H.; DeWitt, Ed; Maron, Marcos A.; Ladeira, Eduardo A.

    2001-07-01

    Brazil has been a major but intermittent producer of gold since its discovery in 1500. Brazil led the world in gold production during the 18th and early 19th centuries. From the late 19th century to the late 20th century, total mining company and garimpeiro production was small and relatively constant at about 5 to 8 t/year. The discovery of alluvial deposits in the Amazon by garimpeiros in the 1970s and the opening of eight mines by mining companies from 1983 to 1990 fueled a major boom in Brazil's gold production, exceeding 100 t/year in 1988 and 1989. However, garimpeiro alluvial production decreased rapidly in the 1990s, to about 10 t/year by 1999. Company production increased about tenfold from about 4 t/year in 1982 to 40 t in 1992. Production from 1992 to the present remained relatively stable, even though several mines were closed or were in the process of closing and no new major mines were put into production during that period. Based on their production history from 1982-1999, 17 gold mines are ranked as major (>20 t) and minor (3-8 t) mines. From 1982-1999, deposits hosted in Archean rocks produced 66% of the gold in Brazil, whereas deposits in Paleoproterozoic and Neoproterozoic rocks accounted for 19% and 15%, respectively. Deposits in metamorphosed sedimentary rocks, especially carbonate-rich rocks and carbonate iron-formation, yielded the great bulk of the gold. Deposits in igneous rocks were of much less importance. The Archean and Paleoproterozoic terranes of Brazil largely lack base-metal-rich volcanogenic massive sulfide deposits, porphyry deposits, and polymetallic veins and sedimentary exhalative deposits. An exception to this is in the Carajás Mineral Province.

  1. Major brazilian gold deposits - 1982 to 1999

    Science.gov (United States)

    Thorman, C.H.; Dewitt, E.; Maron, M.A.; Ladeira, E.A.

    2001-01-01

    Brazil has been a major but intermittent producer of gold since its discovery in 1500. Brazil led the world in gold production during the 18th and early 19th centuries. From the late 19th century to the late 20th century, total mining company and garimpeiro production was small and relatively constant at about 5 to 8 t/year. The discovery of alluvial deposits in the Amazon by garimpeiros in the 1970s and the opening of eight mines by mining companies from 1983 to 1990 fueled a major boom in Brazil's gold production, exceeding 100 t/year in 1988 and 1989. However, garimpeiro alluvial production decreased 'rapidly in the 1990s, to about 10 t/year by 1999. Company production increased about tenfold from about 4 t/year in 1982 to 40 t in 1992. Production from 1992 to the present remained relatively stable, even though several mines were closed or were in the process of closing and no new major mines were put into production during that period. Based on their production history from 1982-1999, 17 gold mines are ranked as major (> 20 t) and minor (3-8 t) mines. From 1982-1999, deposits hosted in Archean rocks produced 66% of the gold in Brazil, whereas deposits in Paleoproterozoic and Neoproterozoic rocks accounted for 19% and 15%, respectively. Deposits in metamorphosed sedimentary rocks, especially carbonate-rich rocks and carbonate iron-formation, yielded the great bulk of the gold. Deposits in igneous rocks were of much less importance. The Archean and Paleoproterozoic terranes of Brazil largely lack base-metal-rich volcanogenic massive sulfide deposits, porphyry deposits, and polymetallic veins and sedimentary exhalative deposits. An exception to this is in the Caraja??s Mineral Province.

  2. Gold nanowires and the effect of impurities

    Directory of Open Access Journals (Sweden)

    Novaes Frederico

    2006-01-01

    Full Text Available AbstractMetal nanowires and in particular gold nanowires have received a great deal of attention in the past few years. Experiments on gold nanowires have prompted theory and simulation to help answer questions posed by these studies. Here we present results of computer simulations for the formation, evolution and breaking of very thin Au nanowires. We also discuss the influence of contaminants, such as atoms and small molecules, and their effect on the structural and mechanical properties of these nanowires.

  3. Aneurysm, arachnoiditis and intrathecal Au (gold)

    International Nuclear Information System (INIS)

    Pence, D.M.; Kim, T.H.; Levitt, S.H.

    1990-01-01

    This report is a 20-year follow-up of 14 patients treated with external beam craniospinal irradiation and intrathecal gold (10-45 mCi) for medulloblastoma. Six of the patients died within 2 years of treatment from persistent disease. No patients are alive without complications. Six of eight surviving patients developed arachnoiditis and cauda equina syndrome within 5 to 10 years of treatment. Seven of eight survivors developed aneurysms and/or cerebrovascular accidents 9 to 20 years after treatment. Four of the cerebrovascular events were fatal. Intrathecal gold pools in the basal cisterns and cauda equina delivering an extremely inhomogeneous dose throughout the neuroaxis. Its use is discouraged

  4. Gold nanoparticle-pentacene memory-transistors

    OpenAIRE

    Novembre , Christophe; Guerin , David; Lmimouni , Kamal; Gamrat , Christian; Vuillaume , Dominique

    2008-01-01

    We demonstrate an organic memory-transistor device based on a pentacene-gold nanoparticles active layer. Gold (Au) nanoparticles are immobilized on the gate dielectric (silicon dioxide) of a pentacene transistor by an amino-terminated self-assembled monolayer. Under the application of writing and erasing pulses on the gate, large threshold voltage shift (22 V) and on/off drain current ratio of ~3E4 are obtained. The hole field-effect mobility of the transistor is similar in the on and off sta...

  5. Modelling spatial anisotropy of gold concentration data using GIS ...

    Indian Academy of Sciences (India)

    Linear trends of anomalously high gold values in the Florida Canyon gold deposit, Nevada have been identified using a ... starting at 3500 ft above mean sea level (msl). Relatively high ..... by slower rise in semivariances for longer distance.

  6. Plasmonic properties of gold-coated nanoporous anodic alumina ...

    Indian Academy of Sciences (India)

    gold-coated NAA is strongly quenched due to the strong plasmonic coupling. Keywords. Plasmon ... When coated by a thin film of gold, these templates can support surface plasmon resonance. ... 2.2 Equipment for characterization. Surface ...

  7. Hydrothermal Gold Mineralization and Structural Controls near May ...

    African Journals Online (AJOL)

    Mickiale

    controlled gold mineralized zones of gold near Workamba. .... consists of rounded to sub-rounded clasts of blue quartz eyes and varies in size from ... Based on the field observation, petrographic study and their cross cutting relationships; four.

  8. New progress of the study on uranium-gold association

    International Nuclear Information System (INIS)

    Feng Mingyue; Sun Zhifu

    1992-01-01

    Through the study on heavy minerals from the uraniferous granite-pegmatite it is found that nature gold is associated with uraninite, which provides the new information for the study on uranium-gold association and its metallogenesis

  9. New progress of the study on uranium-gold association

    Energy Technology Data Exchange (ETDEWEB)

    Mingyue, Feng; Zhifu, Sun [Beijing Research Inst. of Uranium Geology (China)

    1992-07-01

    Through the study on heavy minerals from the uraniferous granite-pegmatite it is found that nature gold is associated with uraninite, which provides the new information for the study on uranium-gold association and its metallogenesis.

  10. Determination of gold coating thickness measurement by using EDXRF

    International Nuclear Information System (INIS)

    Meor Yusoff Meor Sulaian; Masliana Muslimin; Fadlullah Jili Fursani

    2005-01-01

    The paper relates a study on the development of an analysis procedure for measuring the gold coating thickness using EDXRF technique. Gold coating thickness was measured by relating the counts under the Au L? peak its thickness value. In order to get a reasonably accurate result, a calibration graph was plotted using five gold-coated reference standards of different thickness. The calibration graph shows a straight line for thin coating measurement until 0.9 μm. Beyond this the relationship was not linear and this may be resulted from the self-absorption effect. Quantitative analysis was also performed on two different samples of gold coated jewelry and a phone connector. Result from the phone connector analysis seems to agree with the manufacturer gold coating value. From the analysis of gold-coated jewelry it had been able to differentiate the two articles as gold wash and gold electroplated. (Author)

  11. Phonon assisted thermophoretic motion of gold nanoparticles inside carbon nanotubes

    DEFF Research Database (Denmark)

    Schoen, Philipp A.E.; Walther, Jens Honore; Poulikakos, Dimos

    2007-01-01

    The authors investigate the thermally driven mass transport of gold nanoparticles confined inside carbon nanotubes using molecular dynamics simulations. The observed thermophoretic motion of the gold nanoparticles correlates with the phonon dispersion exhibited by a standard carbon nanotube and...

  12. Metallogenic epoch of the Jiapigou gold belt, Jilin Province, China

    Indian Academy of Sciences (India)

    Metallogenic epoch of the Jiapigou gold belt, Jilin Province, China: ... The Jiapigou gold belt is located on the northern margin of the North China Craton, and is one of the ... 29, Xueyuan Road, Beijing 100083, People's Republic of China.

  13. Albumin-gold-glutathione is a probable auranofin metabolite

    International Nuclear Information System (INIS)

    Shaw, C.F. III; Coffer, M.; Isab, A.A.

    1989-01-01

    The newly licensed gold drug, auranofin ((2,3,4,6-tetra-O-acetyl-β-1-D-gluco-pyranosato-S-)triethylphoshine-gold(I)) crosses cell membranes and enters cells which are inaccessible to parenteral gold drugs. In vivo, the triethylphosphine ligand and gold of auranofin, but not the thio-sugar moiety, accumulate in and subsequently efflux from red blood cells (RBCs). Extracellular albumin increases in the extent of gold efflux and acts as a gold binding site. The rate of efflux is first-order in RBC gold concentration. Studies using RBCs in which labelled [ 14 C]-glutathione is generated in situ incorporation of [ 14 C]- glycine demonstrate that glutathione also effluxes from the RBCs and forms a gold-glutathione-albumin complex. This may be the immunopharmacologically active complex

  14. Surface-enhanced Raman scattering on gold nanotrenches and nanoholes

    KAUST Repository

    Yue, Weisheng; Yang, Yang; Wang, Zhihong; Chen, Longqing; Wong, Ka Chun; Syed, Ahad A.; Chen, Zong; Wang, Xianbin

    2012-01-01

    Dependent effects on edge-to-edge distance and incidence polarization in surface-enhanced Raman Scattering (SERS) were studied in detection of 4-mercaptopyridine (4-MPy) molecules absorbed on gold nanotrenches and nanoholes. The gold nanostructures

  15. A Preliminary Study on Detecting Fake Gold Bars Using Prompt Gamma Activation Analysis: Simulation of Neutron Transmission in Gold Bar

    International Nuclear Information System (INIS)

    Lee, K. M.; Sun, G. M.

    2016-01-01

    The purpose of this study is to develop fake gold bar detecting method by using Prompt-gamma activation analysis (PGAA) facility at the Korea Atomic Energy Research Institute (KAERI). PGAA is an established nuclear analytical technique for non-destructive determination of elemental and isotopic compositions. For a preliminary study on detecting fake gold bar, Monte Carlo simulation of neutron transmission in gold bar was conducted and the possibility for detecting fake gold bar was confirmed. Under the gold bullion standard, it guaranteed the government would redeem any amount of currency for its value in gold. After the gold bullion standard ended, gold bars have been the target for investment as ever. But it is well known that fake gold bar exist in the gold market. This cannot be identified easily without performing a testing as it has the same appearance as the pure gold bar. In order to avoid the trading of fake gold bar in the market, they should be monitored thoroughly. Although the transmissivity of cold neutrons are low comparing that of thermal neutrons, the slower neutrons are more apt to be absorbed in a target, and can increase the prompt gamma emission rate. Also the flux of both thermal and cold neutron beam is high enough to activate thick target. If the neutron beam is irradiated on the front and the reverse side of gold bar, all insides of it can be detected

  16. A Preliminary Study on Detecting Fake Gold Bars Using Prompt Gamma Activation Analysis: Simulation of Neutron Transmission in Gold Bar

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K. M.; Sun, G. M. [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    The purpose of this study is to develop fake gold bar detecting method by using Prompt-gamma activation analysis (PGAA) facility at the Korea Atomic Energy Research Institute (KAERI). PGAA is an established nuclear analytical technique for non-destructive determination of elemental and isotopic compositions. For a preliminary study on detecting fake gold bar, Monte Carlo simulation of neutron transmission in gold bar was conducted and the possibility for detecting fake gold bar was confirmed. Under the gold bullion standard, it guaranteed the government would redeem any amount of currency for its value in gold. After the gold bullion standard ended, gold bars have been the target for investment as ever. But it is well known that fake gold bar exist in the gold market. This cannot be identified easily without performing a testing as it has the same appearance as the pure gold bar. In order to avoid the trading of fake gold bar in the market, they should be monitored thoroughly. Although the transmissivity of cold neutrons are low comparing that of thermal neutrons, the slower neutrons are more apt to be absorbed in a target, and can increase the prompt gamma emission rate. Also the flux of both thermal and cold neutron beam is high enough to activate thick target. If the neutron beam is irradiated on the front and the reverse side of gold bar, all insides of it can be detected.

  17. Formation of gold nanoparticles by glycolipids of Lactobacillus casei

    OpenAIRE

    Kikuchi, Fumiya; Kato, Yugo; Furihata, Kazuo; Kogure, Toshihiro; Imura, Yuki; Yoshimura, Etsuro; Suzuki, Michio

    2016-01-01

    Gold nanoparticles have particular properties distinct from those of bulk gold crystals, and such nanoparticles are used in various applications in optics, catalysis, and drug delivery. Many reports on microbial synthesis of gold nanoparticles have appeared. However, the molecular details (reduction and dispersion) of such synthesis remain unclear. In the present study, we studied gold nanoparticle synthesis by Lactobacillus casei. A comparison of L. casei components before and after addition...

  18. Using mineralogy to optimize gold recovery by direct cyanidation

    Science.gov (United States)

    Venter, D.; Chryssoulis, S. L.; Mulpeter, T.

    2004-08-01

    The complete and accurate gold deportments of direct cyanide leach residues provide a clear picture of the occurrence of unrecovered gold and identify causes for poor extraction. Based on the independent measurement of each form and carrier of unleached gold, opportunities for recovery optimization can be assessed more accurately by providing meaningful targets and can help identify the means to achieve such targets. In ten of 14 leach plants surveyed, 23% of the unrecovered gold could be extracted without finer grinding.

  19. Natural gold composition studied by proton activation analysis (PAA)

    International Nuclear Information System (INIS)

    Cojocaru, V.; Badica, T.; Popescu, I.V.

    2003-01-01

    The minor and trace element concentration of natural gold is essential for provenance studies of gold archaeological artifacts. In this work proton activation analysis is used in order to find what elements can be put into evidence in natural gold. For that purpose some gold nuggets from Romania were used. It was found that PAA is a good supplemental method to neutron activation analysis. (authors)

  20. Comment: 190 [Taxonomy Icon

    Lifescience Database Archive (English)

    Full Text Available 90.png Takeshi Kawashima (OIST) licensed under CC Attribution2.1 Japan 写真提供:川島武士(沖縄科学技術研究基盤整備機構) Photo: Take...shi Kawashima (OIST) 川島武士さんに頂きました写真より作図いたしました。 ttamura 2009/05/07 17:47:40 2010/01/14 20:02:14 ...

  1. Cranked relativistic Hartree-Bogoliubov theory: formalism and application to the superdeformed bands in the A∼190 region

    International Nuclear Information System (INIS)

    Afanasjev, A.V.; Ring, P.; Koenig, J.

    2000-01-01

    Cranked relativistic Hartree-Bogoliubov theory without and with approximate particle number projection by means of the Lipkin-Nogami method is presented in detail as an extension of relativistic mean field theory with pairing correlations to the rotating frame. Pairing correlations are taken into account by a finite range two-body force of Gogny type. The applicability of this theory to the description of rotating nuclei is studied in detail on the example of superdeformed bands in even-even nuclei of the A∼190 mass region. Different aspects such as the importance of pairing and particle number projection, the dependence of the results on the parametrization of the RMF Lagrangian and Gogny force, etc., are investigated in detail. It is shown that without any adjustment of new parameters the best description of experimental data is obtained by using the well established parameter sets NL1 for the Lagrangian and D1S for the pairing force. Contrary to previous studies at spin zero it is found that the increase of the strength of the Gogny force is not necessary in the framework of relativistic Hartree-Bogoliubov theory provided that particle number projection is performed

  2. Light isovector resonances in $\\pi^- p \\to \\pi^-\\pi^-\\pi^+ p$ at 190 GeV/${\\it c}$

    CERN Document Server

    Akhunzyanov, R.; The COMPASS collaboration; Alexeev, G.D.; Amoroso, A.; Andrieux, V.; Anfimov, N.V.; Anosov, V.; Antoshkin, A.; Augsten, K.; Augustyniak, W.; Austregesilo, A.; Azevedo, C.D.R.; Badełek, B.; Balestra, F.; Ball, M.; Barth, J.; Beck, R.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E.R.; Birsa, R.; Bodlak, M.; Bordalo, P.; Bradamante, F.; Bressan, A.; Büchele, M.; Burtsev, V.E.; Chang, W.-C.; Chatterjee, C.; Chiosso, M.; Chumakov, A.G.; Chung, S.-U.; Cicuttin, A.; Crespo, M.L.; Dalla Torre, S.; Dasgupta, S.S.; Dasgupta, S.; Denisov, O.Yu.; Dhara, L.; Donskov, S.V.; Doshita, N.; Dreisbach, Ch.; Dünnweber, W.; Dusaev, R.R.; Dziewiecki, M.; Efremov, A.; Eversheim, P.D.; Faessler, M.; Ferrero, A.; Finger, M.; Finger, M., jr.; Fischer, H.; Franco, C.; du Fresne von Hohenesche, N.; Friedrich, J.M.; Frolov, V.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Giarra, J.; Gnesi, I.; Gorzellik, M.; Grasso, A.; Gridin, A.; Grosse Perdekamp, M.; Grube, B.; Guskov, A.; Hahne, D.; Hamar, G.; von Harrach, D.; Heitz, R.; Herrmann, F.; Horikawa, N.; d'Hose, N.; Hsieh, C.-Y.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jary, V.; Joosten, R.; Jörg, P.; Kabuß, E.; Kerbizi, A.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu.A.; Kisselev, Yu.; Klein, F.; Koivuniemi, J.H.; Kolosov, V.N.; Kondo, K.; Konorov, I.; Konstantinov, V.F.; Kotzinian, A.M.; Kouznetsov, O.M.; Kral, Z.; Krämer, M.; Krinner, F.; Kroumchtein, Z.V.; Kulinich, Y.; Kunne, F.; Kurek, K.; Kurjata, R.P.; Kuznetsov, I.I.; Kveton, A.; Lednev, A.A.; Levchenko, E.A.; Levorato, S.; Lian, Y.-S.; Lichtenstadt, J.; Longo, R.; Lyubovitskij, V.E.; Maggiora, A.; Magnon, A.; Makins, N.; Makke, N.; Mallot, G.K.; Mamon, S.A.; Marianski, B.; Martin, A.; Marzec, J.; Matoušek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.V.; Meyer, M.; Meyer, W.; Mikhailov, Yu.V.; Mikhasenko, M.; Mitrofanov, E.; Mitrofanov, N.; Miyachi, Y.; Moretti, A.; Nagaytsev, A.; Nerling, F.; Neyret, D.; Nový, J.; Nowak, W.-D.; Nukazuka, G.; Nunes, A.S.; Olshevsky, A.G.; Orlov, I.; Ostrick, M.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peng, J.-C.; Pereira, F.; Pešek, M.; Pešková, M.; Peshekhonov, D.V.; Pierre, N.; Platchkov, S.; Pochodzalla, J.; Polyakov, V.A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Riedl, C.; Ryabchikov, D.I.; Rybnikov, A.; Rychter, A.; Salac, R.; Samoylenko, V.D.; Sandacz, A.; Sarkar, S.; Savin, I.A.; Sawada, T.; Sbrizzai, G.; Schmieden, H.; Seder, E.; Selyunin, A.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Smolik, J.; Srnka, A.; Steffen, D.; Stolarski, M.; Subrt, O.; Sulc, M.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Tasevsky, M.; Tessaro, S.; Tessarotto, F.; Thiel, A.; Tomsa, J.; Tosello, F.; Tskhay, V.; Uhl, S.; Vasilishin, B.I.; Vauth, A.; Veit, B.M.; Veloso, J.; Vidon, A.; Virius, M.; Wallner, S.; Wilfert, M.; Zaremba, K.; Zavada, P.; Zavertyaev, M.; Zemlyanichkina, E.; Zhuravlev, N.; Ziembicki, M.

    2018-01-01

    We have performed the most comprehensive resonance-model fit of $ \\pi^-\\pi^-\\pi^+$ states using the results of our previously published partial-wave analysis (PWA) of a large data set of diffractive-dissociation events from the reaction $\\pi^- +p \\to \\pi^-\\pi^-\\pi^+ +p_{recoil}$ with a 190 GeV/${\\it c}$ pion beam. The PWA results, which were obtained in 100~bins of three-pion mass, 0.5 < ~$m_{3\\pi}$ < 2.5 GeV/${\\it c}$$^2$, and simultaneously in 11~bins of the reduced four-momentum transfer squared, 0.1 < $t'$ < 1.0 (GeV/${\\it c}$)$^2$, are subjected to a resonance-model fit using Breit-Wigner amplitudes to simultaneously describe a subset of 14~selected waves using 11~isovector light-meson states with $J^{PC} = 0^{-+}$, $1^{++}$, $2^{++}$, $2^{-+}$, $4^{++}$, and spin-exotic $1^{-+}$ quantum numbers. The model contains the well-known resonances $\\pi$(1800), $a_1$(1260), $a_2$(1320), $\\pi_2$(1670), $\\pi_2$(1880), and $a_4$(2040). In addition, it includes the dispute...

  3. Prognostic value of echocardiography in 190 patients with chronic congestive heart failure. A comparison with New York Heart Association functional classes and radionuclide ventriculography

    DEFF Research Database (Denmark)

    Madsen, B K; Videbaek, R; Stokholm, H

    1996-01-01

    Survival in 190 consecutive patients with congestive heart failure, discharged from a general hospital, was studied. Sixteen patients were in New York Heart Association (NYHA) class I, 87 in II, 83 in III and 4 in IV. Median left ventricular ejection fraction (LVEF) from radionuclide...

  4. Gold-coated nanoparticles for use in biotechnology applications

    Science.gov (United States)

    Berning, Douglas E [Los Alamos, NM; Kraus, Jr., Robert H.; Atcher, Robert W [Los Alamos, NM; Schmidt, Jurgen G [Los Alamos, NM

    2009-07-07

    A process of preparing gold-coated magnetic nanoparticles is disclosed and includes forming a suspension of magnetic nanoparticles within a suitable liquid, adding an amount of a reducible gold compound and a reducing agent to the suspension, and, maintaining the suspension for time sufficient to form gold-coated magnetic nanoparticles.

  5. Protracted elimination of gold nanoparticles from mouse liver

    DEFF Research Database (Denmark)

    Sadauskas, Evaldas; Wallin, Håkan; Stoltenberg, Meredin

    2009-01-01

    The present study aims at revealing the fate of 40-nm gold nanoparticles after intravenous injections. The gold nanoparticles were traced histochemically with light and transmission electron microscopy using autometallographic (AMG) staining, and the gold content in the liver was determined with ...

  6. Quinone-Enriched Gold Nanoparticles in Bioelectrochemistry and Charge Storage

    DEFF Research Database (Denmark)

    Wagner, Michal; Qvortrup, Katrine; Tanner, David Ackland

    for merging gold nanoparticles with resultant anthraquinones include one-pot microwave assisted synthesis or after-mixing of separately prepared gold nanoparticles with selected compounds. The quinone-enriched gold nanoparticles can be transferred onto different electrode surfaces, thus enabling facile...

  7. Gold nanoparticles: preparation, functionalisation and applications in biochemistry and immunochemistry

    International Nuclear Information System (INIS)

    Dykman, Lev A; Bogatyrev, Vladimir A

    2007-01-01

    The review summarises data on the synthesis and functionalisation of gold nanoparticles and their applications in biological investigations. Particular attention is given to applications of colloidal gold in solid-phase assays, immunoassay and studies of biologically active compounds by vibrational spectroscopy. A special section deals with the use of gold nanoparticles as antigen carriers in immunisation.

  8. An experimental study on gold precipitation from leach solutions of ...

    African Journals Online (AJOL)

    This paper presents the results of the study dedicated to the determination of the optimum parameters for the electrolytic gold precipitation from thiourea leach solutions. The leaching was carried out using technogenic gold-bearing raw materials (gold-bearing sands) of the Far East of the Russian Federation. The study ...

  9. Crystal growth, structure and phase studies on gold halides

    NARCIS (Netherlands)

    Janssen, Eugenius Maria Wilhelmus Janssen

    1977-01-01

    Only very corrosive substances attack gold, the most noble metal. In this study the reactivity and the phase diagrams of gold with the halogens chlorine, bromine and iodine have been investigated. owing to the noble behaviour of gold, its halides are sensitive to heat; on heating they decompose into

  10. Preg-robbing of Gold by Carbonaceous Materials Encountered in ...

    African Journals Online (AJOL)

    Processing of gold from refractory ores containing carbonaceous materials (CM) poses challenges due to the ability of the CM to preg-rob dissolved gold. Depending on the type and maturity of CM encountered, preg-robbing of aurocyanide ion can lead to reduction in gold recovery ranging from a few percentages to more ...

  11. 76 FR 60355 - Gold Star Mother's and Family's Day, 2011

    Science.gov (United States)

    2011-09-28

    ... Gold Star Mother's and Family's Day, 2011 By the President of the United States of America A... grief their families carry we can never fully know. Gold Star mothers and families know the immeasurable... inspired by their strength and determination. Through heartbreaking loss, our Gold Star families continue...

  12. Increased cellular uptake of peptide-modified PEGylated gold nanoparticles.

    Science.gov (United States)

    He, Bo; Yang, Dan; Qin, Mengmeng; Zhang, Yuan; He, Bing; Dai, Wenbing; Wang, Xueqing; Zhang, Qiang; Zhang, Hua; Yin, Changcheng

    2017-12-09

    Gold nanoparticles are promising drug delivery vehicles for nucleic acids, small molecules, and proteins, allowing various modifications on the particle surface. However, the instability and low bioavailability of gold nanoparticles compromise their clinical application. Here, we functionalized gold nanoparticles with CPP fragments (CALNNPFVYLI, CALRRRRRRRR) through sulfhydryl PEG to increase their stability and bioavailability. The resulting gold nanoparticles were characterized with transmission electron microscopy (TEM), dynamic light scattering (DLS), UV-visible spectrometry and X-ray photoelectron spectroscopy (XPS), and the stability in biological solutions was evaluated. Comparing to PEGylated gold nanoparticles, CPP (CALNNPFVYLI, CALRRRRRRRR)-modified gold nanoparticles showed 46 folds increase in cellular uptake in A549 and B16 cell lines, as evidenced by the inductively coupled plasma atomic emission spectroscopy (ICP-AES). The interactions between gold nanoparticles and liposomes indicated CPP-modified gold nanoparticles bind to cell membrane more effectively than PEGylated gold nanoparticles. Surface plasmon resonance (SPR) was used to measure interactions between nanoparticles and the membrane. TEM and uptake inhibitor experiments indicated that the cellular entry of gold nanoparticles was mediated by clathrin and macropinocytosis. Other energy independent endocytosis pathways were also identified. Our work revealed a new strategy to modify gold nanoparticles with CPP and illustrated the cellular uptake pathway of CPP-modified gold nanoparticles. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Benchmarking Density Functionals for Chemical Bonds of Gold

    DEFF Research Database (Denmark)

    Kepp, Kasper Planeta

    2017-01-01

    Gold plays a major role in nanochemistry, catalysis, and electrochemistry. Accordingly, hundreds of studies apply density functionals to study chemical bonding with gold, yet there is no systematic attempt to assess the accuracy of these methods applied to gold. This paper reports a benchmark aga...

  14. Surface interactions between gold nanoparticles and biochar

    Science.gov (United States)

    Engineered nanomaterials are directly applied to agricultural soils as a part of pesticide/fertilize formulations and sludge/manure amendments. Yet, no prior reports are available on the extent and reversibility of gold nanoparticles (nAu) retention by soil components including charcoal black carbo...

  15. Bacterial leaching of pyritic gold ores

    International Nuclear Information System (INIS)

    Gagliardi, F.M.; Cashion, J.D.; Brown, J.; Jay, W.H.

    1998-01-01

    Full text: Pyritic ores (pyrite and arsenopyrite) containing gold concentrations in excess of 50g Au/t can be processed to recover the gold by the removal of the sulphur from the ore. This may be achieved by roasting (producing sulphur dioxide emissions), pressure oxidation (expensive and suitable for large high grade deposits), pressure leaching (still currently being developed) or bacterial oxidation. The bacterial oxidation process is a well known process in nature but has only recently come under investigation as a economically viable and relatively clean method of gold recovery from deep low grade sulphidic ores. Samples were obtained from the Wiluna Gold Mine in Western Australia consisting of the original ore, six successive bacterial reactors and the final products. Moessbauer experiments have been performed at room temperature, liquid nitrogen and liquid helium temperatures, and in applied magnetic fields. The main components of the iron phases which were present during the bacterial treatment were pyrite and arsenopyrite which were readily oxidised by the bacteria. Ferric sulfates and ferric arsenates were identified as by-products of the process with a small amount of the oxyhydroxide goethite. These results are in contrast to the similar study of the Fairview Mine in South Africa where principally Fe(II) species were observed

  16. Deposition kinetics of nanocolloidal gold particles

    NARCIS (Netherlands)

    Brouwer, E.A.M.; Kooij, Ernst S.; Hakbijl, Mark; Wormeester, Herbert; Poelsema, Bene

    2005-01-01

    The deposition kinetics of the irreversible adsorption of citrate-stabilized, nanocolloidal gold particles on Si/SiO2 surfaces, derivatized with (aminopropyl)triethoxysilane (APTES), is investigated in situ using single wavelength optical reflectometry. A well-defined flow of colloids towards the

  17. A nanoporous gold membrane for sensing applications

    Directory of Open Access Journals (Sweden)

    Swe Zin Oo

    2016-03-01

    Full Text Available Design and fabrication of three-dimensionally structured, gold membranes containing hexagonally close-packed microcavities with nanopores in the base, are described. Our aim is to create a nanoporous structure with localized enhancement of the fluorescence or Raman scattering at, and in the nanopore when excited with light of approximately 600 nm, with a view to provide sensitive detection of biomolecules. A range of geometries of the nanopore integrated into hexagonally close-packed assemblies of gold micro-cavities was first evaluated theoretically. The optimal size and shape of the nanopore in a single microcavity were then considered to provide the highest localized plasmon enhancement (of fluorescence or Raman scattering at the very center of the nanopore for a bioanalyte traversing through. The optimized design was established to be a 1200 nm diameter cavity of 600 nm depth with a 50 nm square nanopore with rounded corners in the base. A gold 3D-structured membrane containing these sized microcavities with the integrated nanopore was successfully fabricated and ‘proof of concept’ Raman scattering experiments are described. Keywords: Nanopore, Polymer sphere, Gold membrane, Plasmons, Sensing, SERS

  18. Photosynthetic light reactions at the gold interface

    NARCIS (Netherlands)

    Kamran, Muhammad

    2014-01-01

    In the project described in this thesis we studied a simple bio-electronic device for solar energy conversion by surface-assembly of photosynthetic pigment-protein complexes on a bare gold-electrode. Optical excitation of the photosynthetic pigments gives rise to charge separation in the so-called

  19. Substoichiometric neutron activation determination of gold

    International Nuclear Information System (INIS)

    Mitchell, J.W.; Riley, J.E. Jr.; Payne, V.

    1978-01-01

    A highly precise and selective method is described for the determination of traces of gold by substoichiometric extraction from hydrochloric acid with tri-n-octylphosphine sulfide in cyclohexane following thermal neutron activation. Fundamental aspects of the extraction system are discussed and results are reported for the determination of gold in an effluent from a recovery process containing a complexed species of gold and unknown amounts of cyanide, citrate, phosphate, potassium and sodium. Other constituents of the effluent stream include traces of the transition elements Co, Ni, Fe, Cu, Zn, Pb and Sn at concentrations less than 50 ppm. One hour was allowed for the Au 3+ carrier and the 198 Au complexed species in samples and standards to oxidize, exchange, and reach chemical equilibrium. Samples were then equilibrated by shaking with the organic phase for thirty min. The percentage extractions (%E) for the substoichiometric separation of gold from the effluent and from the corresponding comparison standards were monitored. The mean percentage extractions for the substoichiometric separations of carrier from the effluent, and its corresponding standard were 75.3 and 59.3, respectively. These data are estimated to be accurate within +-2.0%. (T.G.)

  20. Uranium and gold in Serra da Jacobina

    International Nuclear Information System (INIS)

    Lemos, J.C.

    1974-01-01

    The study in details of the conglomerates of Serra do Corrego Formation is presented. In the Canavieira Gold Mine we made the radiometric research of the work front, sistematic sampling and gamma-ray of drilled holes. Many ore products from the jig of Canavieira Mine were analysed to determine a representative uranium content

  1. Gold nanoparticles as nanosources of heat

    Science.gov (United States)

    Baffou, Guillaume

    2018-04-01

    Under illumination at their plasmonic resonance wavelength, gold nanoparticles can absorb incident light and turn into efficient nanosources of heat remotely controllable by light. This fundamental scheme is at the basis of an active field of research coined thermoplasmonics and encompasses numerous applications in physics, chemistry and biology at the micro and nano scales. Warning, no authors found for 2018Phot........48.

  2. Absorption Spectra of Gold Nanoparticle Suspensions

    Science.gov (United States)

    Anan'eva, M. V.; Nurmukhametov, D. R.; Zverev, A. S.; Nelyubina, N. V.; Zvekov, A. A.; Russakov, D. M.; Kalenskii, A. V.; Eremenko, A. N.

    2018-02-01

    Three gold nanoparticle suspensions are obtained, and mean radii in distributions - (6.1 ± 0.2), (11.9 ± 0.3), and (17.3 ± 0.7) nm - are determined by the transmission electron microscopy method. The optical absorption spectra of suspensions are obtained and studied. Calculation of spectral dependences of the absorption index of suspensions at values of the gold complex refractive index taken from the literature showed a significant deviation of experimental and calculated data in the region of 450-800 nm. Spectral dependences of the absorption of suspensions are simulated within the framework of the Mie-Drude theory taking into account the interband absorption in the form of an additional term in the imaginary part of the dielectric permittivity of the Gaussian type. It is shown that to quantify the spectral dependences in the region of the plasmon absorption band of nanoparticles, correction of the parameters of the interband absorption is necessary in addition to the increase of the relaxation parameter of the Drude theory. Spectral dependences of the dielectric permittivity of gold in nanodimensional state are refined from the solution of the inverse problem. The results of the present work are important for predicting the special features of operation of photonic devices and optical detonators based on gold nanoparticles.

  3. The golden age: gold nanoparticles for biomedicine†

    Science.gov (United States)

    Dreaden, Erik C.; Alkilany, Alaaldin M.; Huang, Xiaohua; Murphy, Catherine J.; El-Sayed, Mostafa A.

    2018-01-01

    Gold nanoparticles have been used in biomedical applications since their first colloidal syntheses more than three centuries ago. However, over the past two decades, their beautiful colors and unique electronic properties have also attracted tremendous attention due to their historical applications in art and ancient medicine and current applications in enhanced optoelectronics and photovoltaics. In spite of their modest alchemical beginnings, gold nanoparticles exhibit physical properties that are truly different from both small molecules and bulk materials, as well as from other nanoscale particles. Their unique combination of properties is just beginning to be fully realized in range of medical diagnostic and therapeutic applications. This critical review will provide insights into the design, synthesis, functionalization, and applications of these artificial molecules in biomedicine and discuss their tailored interactions with biological systems to achieve improved patient health. Further, we provide a survey of the rapidly expanding body of literature on this topic and argue that gold nanotechnology-enabled biomedicine is not simply an act of ‘gilding the (nanomedicinal) lily’, but that a new ‘Golden Age’ of biomedical nanotechnology is truly upon us. Moving forward, the most challenging nanoscience ahead of us will be to find new chemical and physical methods of functionalizing gold nanoparticles with compounds that can promote efficient binding, clearance, and biocompatibility and to assess their safety to other biological systems and their long-term term effects on human health and reproduction (472 references). PMID:22109657

  4. Gold(III)-Catalyzed Hydration of Phenylacetylene

    Science.gov (United States)

    Leslie, J. Michelle; Tzeel, Benjamin A.

    2016-01-01

    A guided inquiry-based experiment exploring the regioselectivity of the hydration of phenylacetylene is described. The experiment uses an acidic gold(III) catalyst in a benign methanol/water solvent system to introduce students to alkyne chemistry and key principles of green chemistry. The experiment can be easily completed in approximately 2 h,…

  5. High-energy band structure of gold

    DEFF Research Database (Denmark)

    Christensen, N. Egede

    1976-01-01

    The band structure of gold for energies far above the Fermi level has been calculated using the relativistic augmented-plane-wave method. The calculated f-band edge (Γ6-) lies 15.6 eV above the Fermi level is agreement with recent photoemission work. The band model is applied to interpret...

  6. Poly-thiosemicarbazide membrane for gold recovery

    KAUST Repository

    Villalobos, Luis Francisco

    2014-11-01

    A novel polymeric membrane adsorber with a high density of adsorption sites that can selectively capture Au(III) ions, is proposed as an efficient alternative to recover gold from dilute solutions. Poly-thiosemicarbazide (PTSC), a polymer that contains one chelate site per monomeric unit, was used to fabricate the membranes. This polymer can be easily processed into membranes by a phase inversion technique, resulting in an open and interconnected porous structure suitable for high flux liquid phase applications. This method overcomes the usual low capacities of membrane adsorbents by selecting a starting material that contains the adsorption sites within it, therefore avoiding the necessity to add an external agent into the membrane matrix. The resulting mechanically stable PTSC membranes can operate in a pressure driven permeation process, which eliminates the diffusion limitations commonly present in packed column adsorption processes. This process can selectively recover 97% of the gold present in a solution containing a 9-fold higher copper concentration, while operating at a flux as high as 1868 L/m2 h. The maximum gold uptake measured without sacrificing the mechanical stability of the membrane was 5.4 mmol Au/g. Furthermore the gold can be easily eluted from the membrane with a 0.1 M thiourea solution and the membrane can be reused for at least three cycles without any decrease in its performance. Finally, the ability of this membrane for recovering metals from real-life samples, like seawater and tap water, was tested with promising results.

  7. Opposition to gold mining at Bergama, Turkey

    NARCIS (Netherlands)

    M. Arsel (Murat)

    2012-01-01

    textabstractIntroduction For much of the 1990s, the tourist town of Bergama was the epicentre of Turkey's most effective and visible environmental social movement against a multinational mining corporation aiming to establish the first modern gold mine in the country. Bringing

  8. Biological synthesis and characterization of intracellular gold ...

    Indian Academy of Sciences (India)

    In the present study, Aspergillus fumigatus was used for the intracellular synthesis of gold nanoparticles. Stable nanoparticles were produced when an aqueous solution of chloroauric acid (HAuCl4) was reduced by A. fumigatus biomass as the reducing agent. Production of nanoparticles was confirmed by the colour ...

  9. Gold Nanoparticles Assembly on Silicon and Gold Surfaces: Mechanism, Stability and Efficiency in Diclofenac Biosensing

    OpenAIRE

    Ben Haddada , Maroua; Hübner , Maria; Casale , Sandra; Knopp , Dietmar; Niessner , Reinhard; Salmain , Michele; Boujday , Souhir

    2016-01-01

    International audience; We investigated the assembly of Gold nanoparticles (AuNPs) on Gold and Silicon sensors with two final objectives: (i) understanding the factors governing the interaction and (ii) building up a nanostructured piezoelectric immunosensor for diclofenac, a small-sized pharmaceutical pollutant. Different surface chemistries were devised to achieve AuNPs assembly on planar substrates. These surface chemistries included amines to immobilize AuNPs via electrostatic interaction...

  10. Corrective Action Decision Document/Closure Report for Corrective Action Unit 190: Contaminated Waste Sites, Nevada Test Site, Nevada, Revision 0

    International Nuclear Information System (INIS)

    Alfred Wickline

    2008-01-01

    This Corrective Action Decision Document/Closure Report has been prepared for Corrective Action Unit (CAU) 190, Contaminated Waste Sites, Nevada Test Site, Nevada, in accordance with the Federal Facility Agreement and Consent Order that was agreed to by the State of Nevada; U.S. Department of Energy, Environmental Management; U.S. Department of Defense; and DOE, Legacy Management (1996, as amended January 2007). Corrective Action Unit 190 is comprised of the following four corrective action sites (CASs): (1) 11-02-01, Underground Centrifuge; (2) 11-02-02, Drain Lines and Outfall; (3) 11-59-01, Tweezer Facility Septic System; (4) 14-23-01, LTU-6 Test Area The purpose of this Corrective Action Decision Document/Closure Report is to provide justification and documentation supporting the recommendation for closure of CAU 190 with no further corrective action. To achieve this, corrective action investigation (CAI) activities were performed from March 21 through June 26, 2007. All CAI activities were conducted as set forth in the Corrective Action Investigation Plan for Corrective Action Unit 190: Contaminated Waste Sites, Nevada Test Site, Nevada (NNSA/NSO, 2006). The purpose of the CAI was to fulfill the following data needs as defined during the data quality objective process: (1) Determine whether contaminants of concern (COCs) are present. (2) If COCs are present, determine their nature and extent. (3) Provide sufficient information and data to complete appropriate corrective actions. The CAU 190 dataset from the investigation results was evaluated based on the data quality indicator parameters. This evaluation demonstrated the quality and acceptability of the dataset for use in fulfilling the data quality objective data needs

  11. Direct formation of gold nanorods on surfaces using polymer-immobilised gold seeds

    Directory of Open Access Journals (Sweden)

    Majid K. Abyaneh

    2016-06-01

    Full Text Available Herein, we present the formation of gold nanorods (GNRs on novel gold–poly(methyl methacrylate (Au–PMMA nanocomposite substrates with unprecedented growth control through the polymer molecular weight (Mw and gold-salt-to-polymer weight ratio. For the first time, GNRs have been produced by seed-mediated direct growth on surfaces that were pre-coated with polymer-immobilised gold seeds. A Au–PMMA nanocomposite formed by UV photoreduction has been used as the gold seed. The influence of polymer Mw and gold concentration on the formation of GNRs has been investigated and discussed. The polymer nanocomposite formed with a lower Mw PMMA and 20 wt % gold salt provides a suitable medium for growing well-dispersed GNRs. In this sample, the average dimension of produced GNRs is 200 nm in length with aspect ratios up to 10 and a distribution of GNRs to nanoparticles of nearly 22%. Suitable characterization techniques such as AFM and SEM have been used to support concept of the proposed growth method.

  12. Occurrences of dendritic gold at the McLaughlin Mine hot-spring gold deposit

    Science.gov (United States)

    Sherlock, R. L.; Lehrman, N. J.

    1995-06-01

    Two styles of gold dendrites are variably developed at the McLaughlin Mine. The most abundant occurrence is hosted by amber-coloured hydrocarbon-rich opal. Silica likely precipitated from a boiling hydrothermal fluid and complexed with immiscible hydrocarbons forming an amorphous hydrocarbon-silica phase. This phase likely scavenged particulate gold by electrostatic attraction to the hydrocarbon-silica phase. The dendritic nature of the gold is secondary and is the result of dewatering of the amorphous hydrocarbon-silica phase and crystallization of gold into syneresis fractures. The second style of dendritic gold is hosted within vein swarms that focused large volumes of fluid flow. The dendrites occur along with hydrocarbon-rich silica at the upper contact of the vein margins which isolated the dendrites allowing sufficient time for them to grow. In a manner similar to the amber-coloured opal, the dendrites may have formed by scavenging particulate gold by electrostatic attraction to the hydrocarbon-silica phase.

  13. Analysis of gold(I/III)-complexes by HPLC-ICP-MS demonstrates gold(III) stability in surface waters.

    Science.gov (United States)

    Ta, Christine; Reith, Frank; Brugger, Joël; Pring, Allan; Lenehan, Claire E

    2014-05-20

    Understanding the form in which gold is transported in surface- and groundwaters underpins our understanding of gold dispersion and (bio)geochemical cycling. Yet, to date, there are no direct techniques capable of identifying the oxidation state and complexation of gold in natural waters. We present a reversed phase ion-pairing HPLC-ICP-MS method for the separation and determination of aqueous gold(III)-chloro-hydroxyl, gold(III)-bromo-hydroxyl, gold(I)-thiosulfate, and gold(I)-cyanide complexes. Detection limits for the gold species range from 0.05 to 0.30 μg L(-1). The [Au(CN)2](-) gold cyanide complex was detected in five of six waters from tailings and adjacent monitoring bores of working gold mines. Contrary to thermodynamic predictions, evidence was obtained for the existence of Au(III)-complexes in circumneutral, hypersaline waters of a natural lake overlying a gold deposit in Western Australia. This first direct evidence for the existence and stability of Au(III)-complexes in natural surface waters suggests that Au(III)-complexes may be important for the transport and biogeochemical cycling of gold in surface environments. Overall, these results show that near-μg L(-1) enrichments of Au in environmental waters result from metastable ligands (e.g., CN(-)) as well as kinetically controlled redox processes leading to the stability of highly soluble Au(III)-complexes.

  14. Morphology dependent electrical transport behavior in gold nanostructures

    International Nuclear Information System (INIS)

    Alkhatib, A.; Souier, T.; Chiesa, M.

    2011-01-01

    The mechanism of electron transport in ultra-thin gold films is investigated and its dependence on the gold islands size is reported. For gold films of thickness below 38 nm, the electrical transport occurs by tunneling within electrically discontinuous islands of gold. Simmons model for metal-insulator-metal junction describes the non-ohmic experimental current-voltage curves obtained by means of conductive atomic force microscopy. Field emission is the predominant transport for thicknesses below 23 nm while direct tunneling occurs in thicker films. The transition between the two regimes is controlled by the gold islands size and their inter-distance.

  15. The activation analysis of gold in small refractory pebbles

    International Nuclear Information System (INIS)

    Bibby, D.M.; Chaix, R.P.

    1975-08-01

    The gold content of a suite of small pebbles, residual to the milling and leach of a gold bearing ore, has been investigated by means of neutron activation analysis (NAA). An NAA technique presenting a sensitivity of 0.02μgm gold, was used as being appropriate to the samples under investigation. An alternative NAA technique developed with the same sample suite showed a sensitivity of the order of 10 -4 to 10 -5 μgm gold. The NAA techniques developed, are appropriate to the determination of gold in small samples of ore not normally amenable to milling and/or dissolution

  16. Theoretical and experimental study of high strain, high strain rate materials viscoplastic behaviour. Application to Mars 190 steel and tantalum

    International Nuclear Information System (INIS)

    Juanicotena, A.

    1998-01-01

    This work enters in the general framework of the study and modelling of metallic materials viscoplastic behaviour in the area of high strain and high strain rate, from 10 4 to 10 5 s -1 . We define a methodology allowing to describe the behaviour of armor steel Mars 190 and tantalum in the initial area. In a first time, the study of visco-plasticity physical mechanisms shows the necessity to take into account some fundamental processes of the plastic deformation. Then, the examination of various constitutive relations allows to select the Preston-Tonks-Wallace model, that notably reproduce the physical phenomenon of the flow stress saturation. In a second part, a mechanical characterization integrating loading direction, strain rate and temperature effects is conducted on the two materials. Moreover, these experimental results allow to calculate associated constants to Preston-Tonks-Wallace, Zerilli-Armstrong and Johnson-Cook models for each material. In a third time, in order to evaluate and to validate these constitutive laws, we conceive and develop an experimental device open to reach the area of study: the expanding spherical shell test. It concerns to impose a free radial expanding to a thin spherical shell by means a shock wave generated by an explosive. By the radial expanding velocity measure, we can determine stress, strain rate and strain applied on the spherical shell at each time. In a four and last part, we evaluate constitutive models out of their optimization area's. This validation is undertaken by comparisons 'experimental results/calculations' with the help of global experiences like expanding spherical shell test and Taylor test. (author)

  17. Alterations of morphology of lymphoid organs and peripheral blood indicators under the influence of gold nanoparticles in rats

    Directory of Open Access Journals (Sweden)

    Alla B. Bucharskaya

    2016-01-01

    Full Text Available At present, gold nanoparticles (GNPs are widely used in biomedical applications such as cancer diagnostics and therapy. Accordingly, the potential toxicity hazards of these nanomaterials and human safety concerns are gaining significant attention. Here, we report the effects of prolonged peroral administration of GNPs with different sizes (2, 15 and 50nm on morphological changes in lymphoid organs and indicators of peripheral blood of laboratory animals. The experiment was conducted on 24 white mongrel male rats weighing 180–220g, gold nanospheres sizes 2, 15 and 50nm were administered orally for 15 days at a dosage of 190μg/kg of animal body weight. The GNPs were conjugated with polyethylene glycol to increase their biocompatibility and bioavailability. The size-dependent decrease of the number of neutrophils and lymphocytes was noted in the study of peripheral blood, especially pronounced after administration of GNPs with size of 50nm. The stimulation of myelocytic germ of hematopoiesis was recorded at morphological study of the bone marrow. The signs of strengthening of the processes of differentiation and maturation of cellular elements were found in lymph nodes, which were showed as the increasing number of immunoblasts and large lymphocytes. The quantitative changes of cellular component morphology of lymphoid organs due to activation of migration, proliferation and differentiation of immune cells indicate the presence of immunostimulation effect of GNPs.

  18. Photochemical fabrication of size-controllable gold nanoparticles on chitosan and their application on catalytic decomposition of acetaldehyde

    International Nuclear Information System (INIS)

    Yu, Chung-Chin; Yang, Kuang-Hsuan; Liu, Yu-Chuan; Chen, Bo-Chuen

    2010-01-01

    In this work, we report a new pathway to prepare size-controllable gold nanoparticles (NPs) on chitosan (Ch) in aqueous solutions for improving catalytic decomposition of acetaldehyde by pure gold NPs at room temperature. First, Au substrates were cycled in deoxygenated aqueous solutions containing 0.1N NaCl and 1 g/L Ch from -0.28 to +1.22 V vs Ag/AgCl at 500 mV/s for 200 scans. Then the solutions were irradiated with UV lights of different wavelengths to prepare size-controllable Au NPs on Ch. Experimental results indicate that the particle sizes of prepared NPs are increased when UV lights with longer wavelengths were employed. The particle sizes of resulted Au NPs can be controlled from 10 to 50 nm. Moreover, the decomposition of acetaldehydes in wines can be significantly enhanced by ca. 190% of magnitude due to the contribution of the adsorption of Au NPs on Ch.

  19. The in vitro formation of placer gold by bacteria

    Science.gov (United States)

    Southam, Gordon; Beveridge, Terrance J.

    1994-10-01

    A laboratory simulation was developed to provide mechanistic information about placer (nugget) gold development in the natural environment. To initiate the simulation, ionic gold was immobilized to a high capacity by Bacillus subtilis 168 (116.2 μg/mg dry weight bacteria) as fine-grained intracellular colloids (5-50 nm). During the low-temperature diagenesis experiment (60°C), the release of organics due to bacterial autolysis coincided with the in vitro formation of hexagonal-octahedral gold crystals (20 μm). This octahedral gold was observed to aggregate, forming fine-grained placer gold (50 μm). In addition to achieving a fundamental understanding into secondary gold deposition, a significant economic benefit could be realized by employing this environmentally safe procedure to concentrate widely dispersed gold in placer deposits to facilitate mining by conventional methodologies.

  20. Use of coal-oil agglomerates for particulate gold recovery

    Energy Technology Data Exchange (ETDEWEB)

    Calvez, J.P.S.; Kim, M.J.; Wong, P.L.M.; Tran, T. [University of New South Wales, Sydney, NSW (Australia). School of Chemical Engineering and Industrial Chemistry

    1998-09-01

    The underlying principles by which gold is recovered by coal-oil agglomerates was investigated. The effects of various parameters such as oil:coal ratios, agglomerate:ore ratios, pH and coal particle size on gold recovery were evaluated using synthetic gold bearing samples, bituminous coal, and diesel oil and kerosene. The effects of sulfides on gold recovery and the depth of gold particle penetration within the agglomerates were also investigated. Results showed that gold recovery was increased by increasing agglomerate:ore ratio, decreasing oil:coal ratio and decreasing coal particle size. There was no significant difference in gold recoveries at pH range of 4-12 and at up to 5% sulfides in the feed.

  1. The use of gold nanoparticles to enhance radiotherapy in mice

    International Nuclear Information System (INIS)

    Hainfeld, James F; Slatkin, Daniel N; Smilowitz, Henry M

    2004-01-01

    Mice bearing subcutaneous EMT-6 mammary carcinomas received a single intravenous injection of 1.9 nm diameter gold particles (up to 2.7 g Au/kg body weight), which elevated concentrations of gold to 7 mg Au/g in tumours. Tumour-to-normal-tissue gold concentration ratios remained ∼8:1 during several minutes of 250 kVp x-ray therapy. One-year survival was 86% versus 20% with x-rays alone and 0% with gold alone. The increase in tumours safely ablated was dependent on the amount of gold injected. The gold nanoparticles were apparently non-toxic to mice and were largely cleared from the body through the kidneys. This novel use of small gold nanoparticles permitted achievement of the high metal content in tumours necessary for significant high-Z radioenhancement. (note)

  2. Synthesis of PEGylated gold nanostars and bipyramids for intracellular uptake

    International Nuclear Information System (INIS)

    Navarro, Julien R G; Lerouge, Frédéric; Chaput, Frédéric; Micouin, Guillaume; Gabudean, Ana-Maria; Baldeck, Patrice L; Kamada, Kenji; Parola, Stephane; Manchon, Delphine; Mosset, Alexis; Cottancin, Emmanuel; Blanchard, Nicholas P; Marotte, Sophie; Leverrier, Yann; Marvel, Jacqueline

    2012-01-01

    A great number of works have focused their research on the synthesis, design and optical properties of gold nanoparticles for potential biological applications (bioimaging, biosensing). For this kind of application, sharp gold nanostructures appear to exhibit the more interesting features since their surface plasmon bands are very sensitive to the surrounding medium. In this paper, a complete study of PEGylated gold nanostars and PEGylated bipyramidal-like nanostructures is presented. The nanoparticles are prepared in high yield and their surfaces are covered with a biocompatible polymer. The photophysical properties of gold bipyramids and nanostars, in suspension, are correlated with the optical response of single and isolated objects. The resulting spectra of isolated gold nanoparticles are subsequently correlated to their geometrical structure by transmission electron microscopy. Finally, the PEGylated gold nanoparticles were incubated with melanoma B16-F10 cells. Dark-field microscopy showed that the biocompatible gold nanoparticles were easily internalized and most of them localized within the cells. (paper)

  3. Preparation of gold nanoparticles by arc discharge in water

    International Nuclear Information System (INIS)

    Lung, Jen-Kuang; Huang, Jen-Chuen; Tien, Der-Chi; Liao, Chih-Yu; Tseng, Kuo-Hsiung; Tsung, Tsing-Tshin; Kao, Wen-Shiow; Tsai, Teh-Hua; Jwo, Ching-Song; Lin, Hong-Ming; Stobinski, Leszek

    2007-01-01

    Gold nanoparticles have been attracting attention due to their extensive application in chemistry, physics, material science, electronics, catalysis and bionanotechnology. Synthesis of gold nanoparticles often involves toxic and expensive physical-chemistry methods. Preparation of gold nanoparticles by arc discharge in water is proposed for the first time. Fabrication of gold nanostructures in deionized water has been successfully established. The evidence of gold particles' light absorbance reveals a unique surface plasmon resonance for Au nanoparticles suspended in deionized water. Gold nanostructures uniformly dispersed in water, their UV-Vis absorption and crystalline size are shown. Our experimental results demonstrate that fabrication of gold nanoparticles by arc discharge in water is an alternative, cheap, effective and environmentally friendly method

  4. Physicochemical Properties of Gold Nanostructures Deposited on Glass

    Directory of Open Access Journals (Sweden)

    Zdenka Novotna

    2014-01-01

    Full Text Available Properties of gold films sputtered onto borosilicate glass substrate were studied. UV-Vis absorption spectra were used to investigate optical parameters. XRD analysis provided information about the gold crystalline nanostructure, the texture, and lattice parameter and biaxial tension was also determined by the XRD method. The surface morphology was examined by atomic force microscopy (AFM; chemical structure of sputtered gold nanostructures was examined by X-ray photoelectron spectroscopy (ARXPS. The gold crystallites are preferentially [111] oriented on the sputtered samples. Gold deposition leads to dramatic changes in the surface morphology in comparison to pristine glass substrate. Oxygen is not incorporated into the gold layer during gold deposition. Experimental data on lattice parameter were also confirmed by theoretical investigations of nanoclusters using tight-binding potentials.

  5. Measurement of the isotope effect of the diffusion of silver and gold in gold and of silver in silver-gold alloys

    International Nuclear Information System (INIS)

    Wolter, D.

    1974-01-01

    The silver isotopes Ag 105 and Agsup(110m) and the gold isotopes Au 195 and Au 199 were used for isotope effect measurements. The isotope effect of the gold self-diffusion was measured on four monocrystals samples at about 850 0 C, that of silver in gold monocrystals at five different temperatures between 731 0 C and 1050 0 C. Furthermore, the isotope effect for silver at 904 0 C was measured on seven silver-gold alloys of varying silver concentration. The correlation factor was determined from the measurements. (HPOE/LH) [de

  6. GOLD-BEARING MINERALIZED ZONES OF THE YUZHNOE ORE OCCURRENCE AND ITS COMPARISON WITH LODE GOLD DEPOSITS OF YENISEI RIDGE

    OpenAIRE

    MANSUROV R.KH.

    2016-01-01

    The relevance of the discussed issue is caused by the need to detect a new gold ore deposits within the Yenisei ridge to replenish the mineral resources of gold ore in Russia. The main aim of the study is to explore the features of geological structure and gold ore mineralized zones of ore occurrence Yuzhnoe in order to forecast gold ore bodies, and to substantiate the continuation of geological exploration. The prospecting is realized by the express method of prospecting of gold ore deposits...

  7. Metamorphic Rock-Hosted Orogenic Gold Deposit Type as a Source of Langkowala Placer Gold, Bombana, Southeast Sulawesi

    OpenAIRE

    Idrus, Arifudin; Nur, I; Warmada, I. W; Fadlin, Fadlin

    2011-01-01

    DOI: 10.17014/ijog.v6i1.114In 2008, placer gold was discovered in Langkowala area (Bombana Regency), Southeast Sulawesi, Indonesia, and more than 60,000 traditional gold miners in the early 2009 have been operating by digging vertical pits and panning active stream sediments. The grade of placer gold ranges from 50 to 140 g/t. Local geological framework indicates that the placer gold is not related to volcanic rock-related hydrothermal gold deposit, e.g. epithermal, skarn or porphyry. This pa...

  8. Coal-oil assisted flotation for the gold recovery

    Energy Technology Data Exchange (ETDEWEB)

    Sen, S.; Seyrankaya, A.; Cilingir, Y. [Dokuz Eylul University, Izmir (Turkey). Mining Engineering Department

    2005-09-01

    Using coal-oil agglomeration method for free or native gold recovery has been a research subject for many researchers over the years. In this study, a new approach 'coal-oil assisted gold flotation' was used to recover gold particles. The coal-oil-gold agglomeration process considers the preferential wetting of coal and gold particles. The method takes advantage of the greater hydrophobicity and oleophilicity of coal and gold compared to that the most gangue materials. Unlike the previous studies about coal-oil-gold agglomeration, this method uses a very small amount of coal and agglomerating agents. Some experiments were conducted on synthetic gold ore samples to reveal the reaction of the coal-oil assisted gold flotation process against the size and the number of gold particles in the feed. It was observed that there is no significant difference in process gold recoveries for feeds assaying different Au. Although there was a slight decrease for coarse gold particles, the process seems to be effective for the recovery of gold grains as coarse as 300 {mu} m. The decrease in the finest size ({lt} 53 {mu} m) is considered to be the decrease in the collision efficiency between the agglomerates and the finest gold particles. The effect of changing coal quantity for constant ore and oil amounts was also investigated. The experiments showed that the process gives very similar results for both artificial and natural ore samples; the best results have been obtained by using 30/1 coal-oil ratio.

  9. Red gold analysis by using gamma absorption tchnique

    International Nuclear Information System (INIS)

    Kurtoglu, A.; Tugrul, A.B.

    2001-01-01

    Gold is a valuable metal and also preferable materials for antique artefacts and some advanced technology products. It can be offered for the analysis of the gold as namely; neutron activation analysis, X-ray florescence technique, Auger spectroscopy, atomic absorption and wet chemistry. Some limitations exist in practice for these techniques, especially in the points of financial and applicability concepts. An advanced a practical technique is gamma absorption technique for the gold alloys. This technique is based on discontinuities in the absorption coefficient for gamma rays at corresponding to the electronic binding energies of the absorber. If irradiation is occurred at gamma absorption energy for gold, absorption rates of the red gold changes via the gold amounts in the alloy. Red gold is a basic and generally preferable alloy that has copper and silver additional of the gold in it. The gold amount defines as carat of the gold. Experimental studies were observed for four different carats of red gold; these are 8, 14, 18 and 22 carats. K-edge energy level of the gold is on 80 keV energy. So, Ba-133 radioisotope is preferred as the gamma source because of it has gamma energy peak in that energy. Experiments observed in the same geometry for all samples. NaI(Tl) detector and multichannel analyser were used for measurements. As a result of the experiments, the calibration curves could be drawn for red gold. For examine this curve, unknown samples are measured in experimental set and it can be determined the carat of it with the acceptability. So the red gold analysis can be observed non-destructively, easily and quickly by using the gamma absorption technique

  10. Antifungal activity of gold nanoparticles prepared by solvothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Tokeer, E-mail: tahmad3@jmi.ac.in [Nanochemistry Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025 (India); Wani, Irshad A.; Lone, Irfan H.; Ganguly, Aparna [Nanochemistry Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025 (India); Manzoor, Nikhat; Ahmad, Aijaz [Department of Biosciences, Jamia Millia Islamia, New Delhi 110025 (India); Ahmed, Jahangeer [Department of Chemistry, Michigan State University, East Lansing, MI 48824 (United States); Al-Shihri, Ayed S. [Department of Chemistry, Faculty of Science, King Khalid University, Abha 61413, P.O. Box 9004 (Saudi Arabia)

    2013-01-15

    Graphical abstract: Gold nanoparticles (7 and 15 nm) of very high surface area (329 and 269 m{sup 2}/g) have been successfully synthesized through solvothermal method by using tin chloride and sodium borohydride as reducing agents. As-prepared gold nanoparticles shows very excellent antifungal activity against Candida isolates and activity increases with decrease in the particle size. Display Omitted Highlights: ► Effect of reducing agents on the morphology of gold nanoparticles. ► Highly uniform and monodisperse gold nanoparticles (7 nm). ► Highest surface area of gold nanoparticles (329 m{sup 2/}g). ► Excellent antifungal activity of gold nanoparticles against Candida strains. -- Abstract: Gold nanoparticles have been successfully synthesized by solvothermal method using SnCl{sub 2} and NaBH{sub 4} as reducing agents. X-ray diffraction studies show highly crystalline and monophasic nature of the gold nanoparticles with face centred cubic structure. The transmission electron microscopic studies show the formation of nearly spherical gold nanoparticles of average size of 15 nm using SnCl{sub 2}, however, NaBH{sub 4} produced highly uniform, monodispersed and spherical gold nanoparticles of average grain size of 7 nm. A high surface area of 329 m{sup 2}/g for 7 nm and 269 m{sup 2}/g for 15 nm gold nanoparticles was observed. UV–vis studies assert the excitations over the visible region due to transverse and longitudinal surface plasmon modes. The gold nanoparticles exhibit excellent size dependant antifungal activity and greater biocidal action against Candida isolates for 7 nm sized gold nanoparticles restricting the transmembrane H{sup +} efflux of the Candida species than 15 nm sized gold nanoparticles.

  11. Antifungal activity of gold nanoparticles prepared by solvothermal method

    International Nuclear Information System (INIS)

    Ahmad, Tokeer; Wani, Irshad A.; Lone, Irfan H.; Ganguly, Aparna; Manzoor, Nikhat; Ahmad, Aijaz; Ahmed, Jahangeer; Al-Shihri, Ayed S.

    2013-01-01

    Graphical abstract: Gold nanoparticles (7 and 15 nm) of very high surface area (329 and 269 m 2 /g) have been successfully synthesized through solvothermal method by using tin chloride and sodium borohydride as reducing agents. As-prepared gold nanoparticles shows very excellent antifungal activity against Candida isolates and activity increases with decrease in the particle size. Display Omitted Highlights: ► Effect of reducing agents on the morphology of gold nanoparticles. ► Highly uniform and monodisperse gold nanoparticles (7 nm). ► Highest surface area of gold nanoparticles (329 m 2/ g). ► Excellent antifungal activity of gold nanoparticles against Candida strains. -- Abstract: Gold nanoparticles have been successfully synthesized by solvothermal method using SnCl 2 and NaBH 4 as reducing agents. X-ray diffraction studies show highly crystalline and monophasic nature of the gold nanoparticles with face centred cubic structure. The transmission electron microscopic studies show the formation of nearly spherical gold nanoparticles of average size of 15 nm using SnCl 2 , however, NaBH 4 produced highly uniform, monodispersed and spherical gold nanoparticles of average grain size of 7 nm. A high surface area of 329 m 2 /g for 7 nm and 269 m 2 /g for 15 nm gold nanoparticles was observed. UV–vis studies assert the excitations over the visible region due to transverse and longitudinal surface plasmon modes. The gold nanoparticles exhibit excellent size dependant antifungal activity and greater biocidal action against Candida isolates for 7 nm sized gold nanoparticles restricting the transmembrane H + efflux of the Candida species than 15 nm sized gold nanoparticles.

  12. Direct determination of thermodynamic activities of gold in the systems gold-palladium and gold-silver-palladium

    International Nuclear Information System (INIS)

    Hoehn, R.; Herzig, C.

    1986-01-01

    The thermodynamic activity of the gold component was directly measured in Au-Pd alloys in the concentration range between X Au =0.048 and 0.850 and in the temperature range 1070 and 1300 K. The ratio of the vapour pressures of pure gold and of the gold component of the alloys was determined - after effusion from a Knudsen twin cell and condensation on a collecting plate - by analysing the decay rate of the radioisotopes 195 Au and 198 Au in an intrinsic germanium well-type detector. The partial mixing enthalpy and the partial mixing entropy of Au were directly obtained from these results. By Gibbs-Duhem integration the integral mixing functions were deduced. Similar measurements were performed in several ternary Au-Ag-Pd alloys of fixed mole fraction X Ag /X Pd =1/9. A comparison of the directly measured partial free excess enthalpy of Au in these ternary alloys with data obtained by the approximate models of Kohler, Toop and Bonnier using data of the corresponding three binary systems yields satisfactory agreement. (orig.) [de

  13. Gold in the hills: patterns of placer gold accumulation under dynamic tectonic and climatic conditions

    Science.gov (United States)

    Roy, Sam; Upton, Phaedra; Craw, Dave

    2018-01-01

    Formation of placer accumulations in fluvial environments requires 103-106 or even greater times concentration of heavy minerals. For this to occur, regular sediment supply from erosion of adjacent topography is required, the river should remain within a single course for an extended period of time and the material must be reworked such that a high proportion of the sediment is removed while a high proportion of the heavy minerals remains. We use numerical modeling, constrained by observations of circum-Pacific placer gold deposits, to explore processes occurring in evolving river systems in dynamic tectonic environments. A fluvial erosion/transport model is used to determine the mobility of placer gold under variable uplift rate, storm intensity, and rock mass strength conditions. Gold concentration is calculated from hydraulic and bedload grain size conditions. Model results suggest that optimal gold concentration occurs in river channels that frequently approach a threshold between detachment-limited and transport-limited hydraulic conditions. Such a condition enables the accumulation of gold particles within the framework of a residual gravel lag. An increase in transport capacity, which can be triggered by faster uplift rates, more resistant bedrock, or higher intensity storm events, will strip all bedload from the channel. Conversely, a reduction in transport capacity, triggered by a reduction in uplift rate, bedrock resistance, or storm intensity, will lead to a greater accumulation of a majority of sediments and a net decrease in gold concentration. For our model parameter range, the optimal conditions for placer gold concentration are met by 103 times difference in strength between bedrock and fault, uplift rates between 1 and 5 mm a-1, and moderate storm intensities. Fault damage networks are shown to be a critical factor for high Au concentrations and should be a target for exploration.

  14. Determination of gold of No. 501 uranium deposits and soil samples by cold leaching gold in dilute aqua regia and collection on activated charcoal

    International Nuclear Information System (INIS)

    Shen Maogen; Yao Liying.

    1989-01-01

    The gold determination method is described by cold leaching gold in dilute aqua regia and collection on activated charcoal and presents the results obtained in determining gold of uranium deposits and soil samples

  15. Ordered arrays of nanoporous gold nanoparticles

    Directory of Open Access Journals (Sweden)

    Dong Wang

    2012-09-01

    Full Text Available A combination of a “top-down” approach (substrate-conformal imprint lithography and two “bottom-up” approaches (dewetting and dealloying enables fabrication of perfectly ordered 2-dimensional arrays of nanoporous gold nanoparticles. The dewetting of Au/Ag bilayers on the periodically prepatterned substrates leads to the interdiffusion of Au and Ag and the formation of an array of Au–Ag alloy nanoparticles. The array of alloy nanoparticles is transformed into an array of nanoporous gold nanoparticles by a following dealloying step. Large areas of this new type of material arrangement can be realized with this technique. In addition, this technique allows for the control of particle size, particle spacing, and ligament size (or pore size by varying the period of the structure, total metal layer thickness, and the thickness ratio of the as-deposited bilayers.

  16. Tamper indicating gold nanocup plasmonic films

    Energy Technology Data Exchange (ETDEWEB)

    DeVetter, Brent M.; Bernacki, Bruce E.; Bennett, Wendy D.; Schemer-Kohrn, Alan; Alvine, Kyle J.

    2017-02-13

    The spectral signature of nanoplasmonic films are both robust and tailorable with optical responses ranging from the visible to the near-infrared. We present the development of flexible, elastomeric nanoplasmonic films consisting of periodic arrays of gold nanocups as tamper indicating films. Gold nanocups have polarization-sensitive optical properties that may be manufactured into films that offer unique advantages for tamper indication. These flexible films can be made quickly and at low-cost using commercially available monodisperse polystyrene nanospheres through self-assembly followed by plasma etching, metal deposition, and lift-off from a sacrificial substrate. Polarization- and angle-dependent optical spectroscopic measurements were performed to characterize the fabricated films. Using polarization-sensitive hyperspectral imaging, we demonstrate how these films can be applied to tamper indication and counterfeit resistance applications.

  17. Formation of Silver and Gold Dendrimer Nanocomposites

    International Nuclear Information System (INIS)

    Balogh, Lajos; Valluzzi, Regina; Laverdure, Kenneth S.; Gido, Samuel P.; Hagnauer, Gary L.; Tomalia, Donald A.

    1999-01-01

    Structural types of dendrimer nanocomposites have been studied and the respective formation mechanisms have been described, with illustration of nanocomposites formed from poly(amidoamine) PAMAM dendrimers and zerovalent metals, such as gold and silver. Structure of {(Au(0)) n- PAMAM} and {(Ag(0)) n- PAMAM} gold and silver dendrimer nanocomposites was found to be the function of the dendrimer structure and surface groups as well as the formation mechanism and the chemistry involved. Three different types of single nanocomposite architectures have been identified, such as internal ('I'), external ('E') and mixed ('M') type nanocomposites. Both the organic and inorganic phase could form nanosized pseudo-continuous phases while the other components are dispersed at the molecular or atomic level either in the interior or on the surface of the template/container. Single units of these nanocomposites may be used as building blocks in the synthesis of nanostructured materials

  18. Biological synthesis of triangular gold nanoprisms

    Science.gov (United States)

    Shankar, S. Shiv; Rai, Akhilesh; Ankamwar, Balaprasad; Singh, Amit; Ahmad, Absar; Sastry, Murali

    2004-07-01

    The optoelectronic and physicochemical properties of nanoscale matter are a strong function of particle size. Nanoparticle shape also contributes significantly to modulating their electronic properties. Several shapes ranging from rods to wires to plates to teardrop structures may be obtained by chemical methods; triangular nanoparticles have been synthesized by using a seeded growth process. Here, we report the discovery that the extract from the lemongrass plant, when reacted with aqueous chloroaurate ions, yields a high percentage of thin, flat, single-crystalline gold nanotriangles. The nanotriangles seem to grow by a process involving rapid reduction, assembly and room-temperature sintering of 'liquid-like' spherical gold nanoparticles. The anisotropy in nanoparticle shape results in large near-infrared absorption by the particles, and highly anisotropic electron transport in films of the nanotriangles.

  19. Synoviorthesis with radioactive gold in hemophiliacs

    International Nuclear Information System (INIS)

    Ahlberg, Aa.; Petterson, H.

    1979-01-01

    Twenty-seven patients with hemophilia treated with intra-articular injection of radioactive gold were followed up clinically and radiologically for 3 to 9 years after treatment. To assess the radiological changes, a new classification was designed, with a score describing the severity of the changes in a more accurate manner than the methods previously used. The treatment decreased the bleeding frequency and stopped the progress of the arthropathy if applied at an early stage when the arthropathy was still reversible. If the treatment was begun at a later stage, the arthropathy seemed to progress independently of the effect on the bleeding frequency. No negative effect of the radioactive gold was observed on the joint or the growing zone. (author)

  20. Gold-bearing hydrothermal veins in Chukotka

    Energy Technology Data Exchange (ETDEWEB)

    Davidenko, N.M.

    1980-01-01

    Indicators such as the correlation of mineralization to plutonic and vulcanic formations and various facies of metamorphism, the character of the structural-tectonic control of mineralization, characteristics of silica redistribution as well that of calcium, water, and other components in altering ore zones, the specificity of sygenetic fluid inclusions in minerals, morphology, the internal structure and other typomorphic indicators of native gold and its accessories are utilized in the working out of a genetic classification for compiling a complex of diagnostic indicators of post-magmatic mineralization on Chukotka at various depths. Those indicators, in addition to earlier known hydrothermal gold ore formations, can be used to identify still other types of mineralization, particularly pyrite group minerals.

  1. Reversible peptide oligomerization over nanoscale gold surfaces

    Directory of Open Access Journals (Sweden)

    Kazushige Yokoyama

    2015-11-01

    Full Text Available A selective oligomeric formation of amyloid beta 1-40 (Ab1-40 monomers over a nanogold colloidal surface was investigated. An unfolded Ab1-40 monomer is considered to construct a dimer or trimer based oligomeric form with its hydrophobic segment placing outward under an acidic condition. Under a basic condition, a conformation of Ab is expected to take a folded monomeric form with its hydrophilic segment folded inward, avoiding the networking with residual colloidal particles. The most probable oligomeric form constructed over a 20 nm gold colloidal surface within a 25 ℃ to 65 ℃ temperature range is a dimer based unit and that over 30 or 40 nm gold colloidal surface below 15 ℃ is concluded to be a trimer based unit. However, selective oligomerization was not successfully reproduced under the rest of the conditions. A dipole-induced dipole interaction must cause a flexible structural change between folded and unfolded forms.

  2. Bacteria diversity and arsenic mobilization in rock biofilm from an ancient gold and arsenic mine.

    Science.gov (United States)

    Tomczyk-Żak, Karolina; Kaczanowski, Szymon; Drewniak, Łukasz; Dmoch, Łukasz; Sklodowska, Aleksandra; Zielenkiewicz, Urszula

    2013-09-01

    In this paper we characterize the biofilm community from an ancient Złoty Stok gold and arsenic mine. Bacterial diversity was examined using a culture-independent technique based on 16S rRNA gene amplification, cloning and sequencing. We show that unexpectedly the microbial diversity of this community was extremely high (more than 190 OTUs detected), with the most numerous members from Rhizobiales (α-Proteobacteria). Although the level of rock biofilm diversity was similar to the microbial mat community we have previously characterized in the same adit, its taxonomic composition was completely different. Detailed analysis of functional arrA and aioA genes, chemical properties of siderophores found in pore water as well as the biofilm chemical composition suggest that the biofilm community contributes to arsenic pollution of surrounding water in a biogeochemical cycle similar to the one observed in bacterial mats. To interpret our results concerning the biological arsenic cycle, we applied the theory of ecological pyramids of Charles Elton. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Poly-thiosemicarbazide Membrane for Gold Adsorption and In-situ Growth of Gold Nanoparticles

    KAUST Repository

    Parra, Luis F.

    2012-12-01

    In this work the synergy between a polymer containing chelate sites and gold ions was explored by the fabrication of a polymeric membrane with embedded gold nanoparticles inside its matrix and by developing a process to recover gold from acidic solutions. After realizing that the thiosemicarbazide groups present in the monomeric unit of poly-thiosemicarbazide (PTSC) formed strong complexes with Au ions, membrane technology was used to exploit this property to its maximum. The incorporation of metal nanoparticles into polymeric matrices with current technologies involves either expensive and complicated procedures or leads to poor results in terms of agglomeration, loading, dispersion, stability or efficient use of raw materials. The fabrication procedure described in this thesis solves these problems by fabricating a PTSC membrane containing 33.5 wt% in the form of 2.9 nm gold nanoparticles (AuNPs) by a three step simple and scalable procedure. It showed outstanding results in all of the areas mentioned above and demonstrated catalytic activity for the reduction of 4-Nitrophenol (4−NP) to 4-Aminophenol (4−AP). The current exponential demand of gold for electronics has encouraged the development of efficient processes to recycle it. Several adsorbents used to recover gold from acidic solutions can be found in the literature with outstanding maximum uptakes,yet, poor kinetics leading to an overall inefficient process. The method developed in this dissertation consisted in permeating the gold-containing solution through a PTSC membrane that will capture all the Au ions by forming a metal complex with them. Forcing the ions through the pores of the membrane eliminates the diffusion limitations and the adsorption will only depended on the fast complexation kinetics, resulting in a very efficient process. A flux as high as 1868 L/h m2 was enough to capture >90% of the precious metal present in a solution of 100 ppm Au. The maximum uptake achieved without sacrificing

  4. Microbial biosynthesis of nontoxic gold nanoparticles

    International Nuclear Information System (INIS)

    Roy, Swarup; Das, Tapan Kumar; Maiti, Guru Prasad; Basu, Utpal

    2016-01-01

    Graphical abstract: The manuscript deals with the fungus mediated optimized biologically synthesized GNPs using Aspergillus foetidus and characterization of biosynthesized GNPs using various physico-chemical methods. The fairly stable synthesized nanoparticles have size in the range of 10–40 nm. Cytotoxicity study of biosynthesized GNPs on Human lung cancer cell line A549 showed no significant toxicity of GNPs. - Highlights: • A novel biosynthesis process of GNPs using Aspergillus foetidus. • Biosynthesized GNPs are in the range of 10–40 nm as observed from TEM. • This process of synthesis is an optimized biosynthesis process of GNPs. • Biosynthesized GNPs are noncytotoxic against A549 cell line. - Abstract: We study the extracellular biosynthesis of gold nanoparticles (GNPs) using the fungal species Aspergillus foetidus. The formation of GNPs were initially monitored by visual observation and then characterized with the help of various characterization techniques. X-ray diffraction (XRD) results revealed distinctive formation of face centered cubic crystalline GNPs. From field emission scanning electron microscopy (FESEM) the morphology of the nanoparticles were found to be roughly spherical and within the size range of 30–50 nm. The spherical and polydispersed GNPs in the range of 10–40 nm were observed by transmission electron microscopy (TEM) analysis. It was established that alkaline pH, 1 mM gold salt concentration and 75 °C temperature were the respective optimum parameter for biosynthesis of GNPs. Cell cytotoxicity of GNP was compared with that of normal gold salt solution on A549 cell. The A549 cell growth in presence of GNPs was found to be comparatively less toxic than the gold ion.

  5. NA35: sulphur-gold collision

    CERN Multimedia

    1991-01-01

    In this image the real particles produced by the collision of a 6400 GeV sulphur ion with a gold target can be seen as they pass through a streamer chamber. Streamer chambers consist of a gas chamber through which a strong pulsed electric field is passed, creating sparks as a charged particle passes through it. The NA35 experiment, which was in operation in the 1980s, was part of CERN's ongoing heavy ion project.

  6. Radiotracer investigation in gold leaching tanks

    Energy Technology Data Exchange (ETDEWEB)

    Dagadu, C.P.K., E-mail: dagadukofi@yahoo.co.uk [Ghana Atomic Energy Commission, P.O. Box LG 80, Legon, Accra (Ghana); Akaho, E.H.K.; Danso, K.A. [Ghana Atomic Energy Commission, P.O. Box LG 80, Legon, Accra (Ghana); Stegowski, Z.; Furman, L. [Faculty of Physics and Applied Computer Science, AGH-UST, 30-059 Krakow (Poland)

    2012-01-15

    Measurement and analysis of residence time distribution (RTD) is a classical method to investigate performance of chemical reactors. In the present investigation, the radioactive tracer technique was used to measure the RTD of aqueous phase in a series of gold leaching tanks at the Damang gold processing plant in Ghana. The objective of the investigation was to measure the effective volume of each tank and validate the design data after recent process intensification or revamping of the plant. I-131 was used as a radioactive tracer and was instantaneously injected into the feed stream of the first tank and monitored at the outlet of different tanks. Both sampling and online measurement methods were used to monitor the tracer concentration. The results of measurements indicated that both the methods provided identical RTD curves. The mean residence time (MRT) and effective volume of each tank was estimated. The tanks-in-series model with exchange between active and stagnant volume was used and found suitable to describe the flow structure of aqueous phase in the tanks. The estimated effective volume of the tanks and high degree of mixing in tanks could validate the design data and confirmed the expectation of the plant engineer after intensification of the process. - Highlights: Black-Right-Pointing-Pointer I-131 radioactive tracer is suitable for tracing the aqueous phase in gold ore slurry. Black-Right-Pointing-Pointer Online data collection is more convenient method for tracer monitoring in industrial process systems. Black-Right-Pointing-Pointer The tanks-in-series model with exchange between active and stagnant zones is suitable to describe the flow behavior of leaching tanks. Black-Right-Pointing-Pointer The radiotracer RTD technique could be used to validate design data after process intensification in gold leaching tanks.

  7. Microbial biosynthesis of nontoxic gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Swarup, E-mail: swaruproy@klyuniv.ac.in [Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal (India); Das, Tapan Kumar [Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal (India); Maiti, Guru Prasad [Department of Molecular Biology and Biotechnology, University of Kalyani, Kalyani 741235, West Bengal (India); Department of Anesthesiology, Texas Tech University Health science Center, 3601 4th Street, Lubbock, TX 79430 (United States); Basu, Utpal [Department of Molecular Biology and Biotechnology, University of Kalyani, Kalyani 741235, West Bengal (India)

    2016-01-15

    Graphical abstract: The manuscript deals with the fungus mediated optimized biologically synthesized GNPs using Aspergillus foetidus and characterization of biosynthesized GNPs using various physico-chemical methods. The fairly stable synthesized nanoparticles have size in the range of 10–40 nm. Cytotoxicity study of biosynthesized GNPs on Human lung cancer cell line A549 showed no significant toxicity of GNPs. - Highlights: • A novel biosynthesis process of GNPs using Aspergillus foetidus. • Biosynthesized GNPs are in the range of 10–40 nm as observed from TEM. • This process of synthesis is an optimized biosynthesis process of GNPs. • Biosynthesized GNPs are noncytotoxic against A549 cell line. - Abstract: We study the extracellular biosynthesis of gold nanoparticles (GNPs) using the fungal species Aspergillus foetidus. The formation of GNPs were initially monitored by visual observation and then characterized with the help of various characterization techniques. X-ray diffraction (XRD) results revealed distinctive formation of face centered cubic crystalline GNPs. From field emission scanning electron microscopy (FESEM) the morphology of the nanoparticles were found to be roughly spherical and within the size range of 30–50 nm. The spherical and polydispersed GNPs in the range of 10–40 nm were observed by transmission electron microscopy (TEM) analysis. It was established that alkaline pH, 1 mM gold salt concentration and 75 °C temperature were the respective optimum parameter for biosynthesis of GNPs. Cell cytotoxicity of GNP was compared with that of normal gold salt solution on A549 cell. The A549 cell growth in presence of GNPs was found to be comparatively less toxic than the gold ion.

  8. Alternative Plasmonic Materials: Beyond Gold and Silver

    DEFF Research Database (Denmark)

    Naik, Gururaj V.; Shalaev, Vladimir M.; Boltasseva, Alexandra

    2013-01-01

    Materials research plays a vital role in transforming breakthrough scientific ideas into next‐generation technology. Similar to the way silicon revolutionized the microelectronics industry, the proper materials can greatly impact the field of plasmonics and metamaterials. Currently, research...... such as gold and silver, that exhibit metallic properties and provide advantages in device performance, design flexibility, fabrication, integration, and tunability. This review explores different material classes for plasmonic and metamaterial applications, such as conventional semiconductors, transparent...

  9. A perspective on gold mine capex

    International Nuclear Information System (INIS)

    Brown, M.F.

    1982-01-01

    Capital expenditure by South Africa's gold and uranium mines is expected to total R5 248 million over the period 1982/1987 - well in excess of the R4 076 million spent in the six years preceding 1982. However, once inflation is taken into account the conclusion is one of declining real capex. This is the view of M F Brown, Chief Economist of the Chamber of Mines of South Africa

  10. Nanotoxicity of gold and iron nanoparticles.

    Science.gov (United States)

    Maiti, Souvik

    2011-02-01

    The extensive use of potentially hazardous nanoparticles in industrial applications suggest that their biological effects need to be evaluated following clinical testing practices as applicable for any new pharmaceutical. It was rationalized that a non hypothesis-driven approach is best suited for discovering the biological effects of nanoparticles. Gold nanoparticles (approximately 18 nm), showed no drastic effect on gene expression in cells but iron nanoparticles showed perturbations in the expression of a set of functional genes.

  11. Radiotracer investigation in gold leaching tanks

    International Nuclear Information System (INIS)

    Dagadu, C.P.K.; Akaho, E.H.K.; Danso, K.A.; Stegowski, Z.; Furman, L.

    2012-01-01

    Measurement and analysis of residence time distribution (RTD) is a classical method to investigate performance of chemical reactors. In the present investigation, the radioactive tracer technique was used to measure the RTD of aqueous phase in a series of gold leaching tanks at the Damang gold processing plant in Ghana. The objective of the investigation was to measure the effective volume of each tank and validate the design data after recent process intensification or revamping of the plant. I-131 was used as a radioactive tracer and was instantaneously injected into the feed stream of the first tank and monitored at the outlet of different tanks. Both sampling and online measurement methods were used to monitor the tracer concentration. The results of measurements indicated that both the methods provided identical RTD curves. The mean residence time (MRT) and effective volume of each tank was estimated. The tanks-in-series model with exchange between active and stagnant volume was used and found suitable to describe the flow structure of aqueous phase in the tanks. The estimated effective volume of the tanks and high degree of mixing in tanks could validate the design data and confirmed the expectation of the plant engineer after intensification of the process. - Highlights: ► I-131 radioactive tracer is suitable for tracing the aqueous phase in gold ore slurry. ► Online data collection is more convenient method for tracer monitoring in industrial process systems. ► The tanks-in-series model with exchange between active and stagnant zones is suitable to describe the flow behavior of leaching tanks. ► The radiotracer RTD technique could be used to validate design data after process intensification in gold leaching tanks.

  12. Broadband Spectroscopy of Nanoporous-Gold Promoter

    Directory of Open Access Journals (Sweden)

    S. K. Nakatani

    2014-02-01

    Full Text Available The efficiency of UV photocatalysis on TiO2 particles was increased by mixing TiO2 particles with nanoporous gold (NPG with pore diameters of 10–40 nm. This means that NPG acts as a promoter in the photocatalytic reaction of TiO2. Broadband spectroscopic results from millimeter wave to ultra violet of NPG membrane are discussed to estimate plasmonic effect on the catalysis.

  13. Application of gold nanoparticles in separation sciences

    Czech Academy of Sciences Publication Activity Database

    Sýkora, D.; Kašička, Václav; Mikšík, Ivan; Řezanka, P.; Záruba, K.; Matějka, P.; Král, V.

    2010-01-01

    Roč. 33, č. 3 (2010), s. 372-387 ISSN 1615-9306 R&D Projects: GA ČR(CZ) GA203/09/0675; GA ČR(CZ) GA203/08/1428; GA MŠk(CZ) 1M0510 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z50110509 Keywords : gold nanoparticles * electrophoresis * chromatography Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.631, year: 2010

  14. Optical characteristics of jewellery gold alloys

    International Nuclear Information System (INIS)

    Wan Mahmood bin Mat Yunus; Zainal Abidin bin Talib; Maarof bin Moksin; Abdul Fatah bin Awang Mat

    1994-01-01

    Measurements of the reflection of various sample of gold alloys were made over the wavelength range 400-800 nm. Samples were measured using a single beam spectrophotometer at 45 deg. angle of incidence. In this measurement no attempt was made to obtain the optical constants of the samples. The results showed that there were significant differences between bulk and thick samples, with sufficient spectra difference between different composition of the alloys

  15. The effects of prolonged oral administration of gold nanoparticles on the morphology of hematopoietic and lymphoid organs

    Science.gov (United States)

    Bucharskaya, Alla B.; Pakhomy, Svetlana S.; Zlobina, Olga V.; Maslyakova, Galina N.; Navolokin, Nikita A.; Matveeva, Olga V.; Khlebtsov, Boris N.; Bogatyrev, Vladimir A.; Khlebtsov, Nikolai G.; Tuchin, Valery V.

    2017-02-01

    Currently, the usage of gold nanoparticles as photosensitizers and immunomodulators for plasmonic photothermal therapy has attracted a great attention of researches and end-users. In our work, the influence of prolonged peroral administration of gold nanoparticles (GNPs) with different sizes on the morphological changes of hematopoietic and lymphoid organs was investigated. The 24 white outbred male rats weighing 180-220 g were randomly divided into groups and administered orally for 30 days the suspension of gold nanospheres with diameters of 2, 15 and 50 nm at a dosage of 190 μg/kg of animal body weight. To prevent GNPs aggregation in a tissue and enhance biocompatibility, they were functionalized with thiolated polyethylene glycol. The withdrawal of the animals from the experiment and sampling of spleen, lymph nodes and bone marrow tissues for morphological study were performed a day after the last administration. In the spleen the boundary between the red and white pulp was not clearly differ in all experimental groups, lymphoid follicles were significantly increased in size, containing bright germinative centers represented by large blast cells. The stimulation of lymphocyte and myelocytic series of hematopoiesis was recorded at morphological study of the bone marrow. The number of immunoblasts and large lymphocytes was increased in all structural zones of lymph nodes. The more pronounced changes were found in the group with administration of 15 nm nanoparticles. Thus, the morphological changes of cellular components of hematopoietic organs have size-dependent character and indicate the activation of the migration, proliferation and differentiation of immune cells after prolonged oral administration of GNPs.

  16. Diazonium-derived aryl films on gold nanoparticles: evidence for a carbon-gold covalent bond.

    Science.gov (United States)

    Laurentius, Lars; Stoyanov, Stanislav R; Gusarov, Sergey; Kovalenko, Andriy; Du, Rongbing; Lopinski, Gregory P; McDermott, Mark T

    2011-05-24

    Tailoring the surface chemistry of metallic nanoparticles is generally a key step for their use in a wide range of applications. There are few examples of organic films covalently bound to metal nanoparticles. We demonstrate here that aryl films are formed on gold nanoparticles from the spontaneous reduction of diazonium salts. The structure and the bonding of the film is probed with surface-enhanced Raman scattering (SERS). Extinction spectroscopy and SERS show that a nitrobenzene film forms on gold nanoparticles from the corresponding diazonium salt. Comparison of the SERS spectrum with spectra computed from density functional theory models reveals a band characteristic of a Au-C stretch. The observation of this stretch is direct evidence of a covalent bond. A similar band is observed in high-resolution electron energy loss spectra of nitrobenzene layers on planar gold. The bonding of these types of films through a covalent interaction on gold is consistent with their enhanced stability observed in other studies. These findings provide motivation for the use of diazonium-derived films on gold and other metals in applications where high stability and/or strong adsorbate-substrate coupling are required.

  17. A halogen-free synthesis of gold nanoparticles using gold(III) oxide

    International Nuclear Information System (INIS)

    Sashuk, Volodymyr; Rogaczewski, Konrad

    2016-01-01

    Gold nanoparticles are one of the most used nanomaterials. They are usually synthesized by the reduction of gold(III) chloride. However, the presence of halide ions in the reaction mixture is not always welcome. In some cases, these ions have detrimental influence on the morphology and structure of resulting nanoparticles. Here, we present a simple and halogen-free procedure to prepare gold nanoparticles by reduction of gold(III) oxide in neat oleylamine. The method provides the particles with an average size below 10 nm and dispersity of tens of percent. The process of nanoparticle formation was monitored using UV–Vis spectroscopy. The structure and chemical composition of the nanoparticles was determined by SEM, XPS and EDX. We also proposed the mechanism of reduction of gold(III) oxide based on MS, IR and NMR data. Importantly, the synthetic protocol is general and applicable for the preparation of other coinage metal nanoparticles from the corresponding metal oxides. For instance, we demonstrated that the absence of halogen enables efficient alloying of metals when preparing gold–silver bimetallic nanoparticles.

  18. Nanostructured gold microelectrodes for extracellular recording

    Energy Technology Data Exchange (ETDEWEB)

    Brueggemann, Dorothea; Wolfrum, Bernhard; Maybeck, Vanessa; Offenhaeusser, Andreas [CNI Center of Nanoelectronic Systems for Information Technology and Institute of Bio- and Nanosystems 2, Forschungszentrum Juelich (Germany)

    2010-07-01

    Electrophysiological activity of electrogenic cells is currently recorded with planar bioelectronic interfaces such as microelectrode arrays (MEAs). In this work, a novel concept of biocompatible nanostructured gold MEAs for extracellular signal recording is presented. MEAs were fabricated using clean room technologies, e.g. photolithography and metallization. Subsequently, they were modified with gold nanopillars of approximately 300 to 400 nm in height and 60 nm width. The nanostructuring process was carried out with a template-assisted approach using nanoporous aluminium oxide. Impedance spectroscopy of the resulting nanostructures showed higher capacitances compared to planar gold. This confirmed the expected increase of the surface area via nanostructuring. We used the nanostructured microelectrodes to record extracellular potentials from heart muscle cells (HL1), which were plated onto the chips. Good coupling between the HL1 cells and the nanostructured electrodes was observed. The resulting signal-to-noise ratio of nanopillar-MEAs was increased by a factor of 2 compared to planar MEAs. In future applications this nanopillar concept can be adopted for distinct interface materials and coupling to cellular and molecular sensing components.

  19. 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.

  20. All That Glitters Is Not Gold

    CERN Multimedia

    2001-01-01

    The surface treatment lab team. From left to right, J. Carosone, M. Malabaila, J-P. Malivert (front row), M. Thiebert, and A. Lasserre (back row). Apiece of stainless steel equipment, destined for the LHC, was delivered to building 102 last Friday morning. This past Monday the equipment emerged from the same building in the afternoon, looking very much the same as it did when it arrived... with one small difference. The equipment was no longer steel, but gold. This may sound like medieval alchemy, but not all is as it appears. In fact there is no sorcery involved, just lots of careful chemical engineering. No wizards either, but rather a talented team of individuals... the CERN surface treatment lab group. Copper, silver, and gold are all incredibly important to particle physics projects because of their ability to conduct electricity with very low resistance. Unfortunately, these metals are also expensive and cannot be used frequently in large quantities. So instead of building equipment out of gold, equi...

  1. Identification of Paracoccidioides brasiliensis by gold nanoprobes

    Science.gov (United States)

    Martins, Jaciara F. S.; Castilho, Maiara L.; Cardoso, Maria A. G.; Carreiro, Andrea P.; Martin, Airton A.; Raniero, Leandro

    2012-01-01

    Paracoccidioides brasiliensis (P. brasiliensis) is a thermal dimorphic fungus and causal agent of paracoccidioidomycosis. Epidemiological data shows that it is mainly concentrated in Central and South America countries, with most registered cases in Colombia, Brazil, and Venezuela. The histopathological similarity with others fungal infection makes the diagnosis of P. brasiliensis more complicated. Therefore, the aim of this work was to find a positive and negative test for P. brasiliensis using gold nanoprobes as a new tool for P. brasiliensis detection. Gold nanoparticles were synthesized by reduction of gold chloride with sodium citrate. The results of this procedure is a wine-red solution with a maximum absorption in the range of ~520-530nm. A specific P. brasiliensis sequence of oligonucleotide was bonded to the nanoparticles, which maintained the wine-red color. The color changes from red to blue for negative diagnostic and is unchanged for a positive test. The H-bond interaction of DNA with the complementary DNA keeps strands together and forms double helical structure, maintaining the colloid stability. However, for non-complimentary DNA sequence the nanoprobes merge into a cluster, changing the light absorption.

  2. Gold, nickel and copper mining and processing.

    Science.gov (United States)

    Lightfoot, Nancy E; Pacey, Michael A; Darling, Shelley

    2010-01-01

    Ore mining occurs in all Canadian provinces and territories except Prince Edward Island. Ores include bauxite, copper, gold, iron, lead and zinc. Workers in metal mining and processing are exposed, not only to the metal of interest, but also to various other substances prevalent in the industry, such as diesel emissions, oil mists, blasting agents, silica, radon, and arsenic. This chapter examines cancer risk related to the mining of gold, nickel and copper. The human carcinogenicity of nickel depends upon the species of nickel, its concentration and the route of exposure. Exposure to nickel or nickel compounds via routes other than inhalation has not been shown to increase cancer risk in humans. As such, cancer sites of concern include the lung, and the nasal sinus. Evidence comes from studies of nickel refinery and leaching, calcining, and sintering workers in the early half of the 20th century. There appears to be little or no detectable risk in most sectors of the nickel industry at current exposure levels. The general population risk from the extremely small concentrations detectable in ambient air are negligible. Nevertheless, animal carcinogenesis studies, studies of nickel carcinogenesis mechanisms, and epidemiological studies with quantitative exposure assessment of various nickel species would enhance our understanding of human health risks associated with nickel. Definitive conclusions linking cancer to exposures in gold and copper mining and processing are not possible at this time. The available results appear to demand additional study of a variety of potential occupational and non-occupational risk factors.

  3. Nanoporous Au: an unsupported pure gold catalyst?

    Energy Technology Data Exchange (ETDEWEB)

    Wittstock, A; Neumann, B; Schaefer, A; Dumbuya, K; Kuebel, C; Biener, M; Zielasek, V; Steinrueck, H; Gottfried, M; Biener, J; Hamza, A; B?umer, M

    2008-09-04

    The unique properties of gold especially in low temperature CO oxidation have been ascribed to a combination of various effects. In particular, particle sizes below a few nm and specific particle-support interactions have been shown to play important roles. On the contrary, recent reports revealed that monolithic nanoporous gold (npAu) prepared by leaching a less noble metal, such as Ag, out of the corresponding alloy can also exhibit remarkably high catalytic activity for CO oxidation, even though no support is present. Therefore, it was claimed to be a pure and unsupported gold catalyst. We investigated npAu with respect to its morphology, surface composition and catalytic properties. In particular, we studied the reaction kinetics for low temperature CO oxidation in detail taking mass transport limitation due to the porous structure of the material into account. Our results reveal that Ag, even if removed almost completely from the bulk, segregates to the surface resulting in surface concentrations of up to 10 at%. Our data suggest that this Ag plays a significant role in activation of molecular oxygen. Therefore, npAu should be considered as a bimetallic catalyst rather than a pure Au catalyst.

  4. sp magnetism in clusters of gold thiolates

    International Nuclear Information System (INIS)

    Ayuela, A; Hernando, A; Echenique, P M; Crespo, P; García, M A

    2012-01-01

    Using first-principles calculations, we consider the bond between thiolate and small Au clusters, with particular emphasis on the resulting magnetic moment. The moment of pure gold clusters is 1 μ B for clusters with an odd number of Au atoms and zero for those with an even number. The addition of the thiolate, having an odd number of electrons itself, shifts the phase of the odd-even oscillations so that particles with an even number of Au atoms now have unit moment. Surprisingly, gold thiolate exhibits a dramatic and non-intuitive distribution of charge and spin moment. Our results show that the S-Au bond is such that sulfur does not get charge and an electron is transferred to the Au cluster. This extra electron is mainly sp in character and resides in an electronic shell below the Au surface. The calculations suggest that any thiolate-induced magnetism occurs in the gold nanoparticle and not the thiolate, and can be controlled by modifying the thiolate coverage. (paper)

  5. Biodistribution of gold nanoparticles following intratracheal instillation in mouse lung

    DEFF Research Database (Denmark)

    Sadauskas, Evaldas; Jacobsen, Nicklas R.; Danscher, Gorm

    2009-01-01

    plasma mass spectrometry (ICP-MS) and neutron activation analysis (NAA). The liver is the major site of deposition of circulating gold nanoparticles. Therefore the degree of translocation was determined by the hepatic deposition of gold. Mice were instilled with 5 intratracheal doses of gold...... repeatedly during 3 weeks, the load was substantial. Ultrastructurally, AMG silver enhanced gold nanoparticles were found in lysosome-/endosome-like organelles of the macrophages and analysis with AMG, ICP-MS and NAA of the liver revealed an almost total lack of translocation of nanoparticles. In mice given...... repeated instillations of 2 nm gold nanoparticles, 1.4‰ (by ICP-MS) to 1.9‰ (by NAA) of the instilled gold was detected in the liver. With the 40 nm gold, no gold was detected in the liver (detection level 2 ng, 0.1‰) except for one mouse in which 3‰ of the instilled gold was found in the liver. No gold...

  6. Structure and reactivity of a mononuclear gold(II) complex

    Science.gov (United States)

    Preiß, Sebastian; Förster, Christoph; Otto, Sven; Bauer, Matthias; Müller, Patrick; Hinderberger, Dariush; Hashemi Haeri, Haleh; Carella, Luca; Heinze, Katja

    2017-12-01

    Mononuclear gold(II) complexes are very rare labile species. Transient gold(II) species have been suggested in homogeneous catalysis and in medical applications, but their geometric and electronic structures have remained essentially unexplored: even fundamental data, such as the ionic radius of gold(II), are unknown. Now, an unprecedentedly stable neutral gold(II) complex of a porphyrin derivative has been isolated, and its structural and spectroscopic features determined. The gold atom adopts a 2+2 coordination mode in between those of gold(III) (four-coordinate square planar) and gold(I) (two-coordinate linear), owing to a second-order Jahn-Teller distortion enabled by the relativistically lowered 6s orbital of gold. The reactivity of this gold(II) complex towards dioxygen, nitrosobenzene and acids is discussed. This study provides insight on the ionic radius of gold(II), and allows it to be placed within the homologous series of nd9 Cu/Ag/Au divalent ions and the 5d8/9/10 Pt/Au/Hg 'relativistic' triad in the periodic table.

  7. The effect of cysteine on electrodeposition of gold nanoparticle

    International Nuclear Information System (INIS)

    Dolati, A.; Imanieh, I.; Salehi, F.; Farahani, M.

    2011-01-01

    Highlights: → Cysteine was found as an appropriate additive for electrodeposition of gold nanoparticles. → The deposition mechanism of gold nanoparticle was determined as instantaneous nucleation. → Oxygen reduction on the gold nanoparticle surface was eight times greater than that on the conventional gold deposits. - Abstract: The most applications of gold nanoparticles are in the photo-electronical accessories and bio-chemical sensors. Chloride solution with cysteine additive was used as electrolyte in gold nanoparticles electrodeposition. The nucleation and growing mechanism were studied by electrochemical techniques such as cyclic voltammetry and chronoamperometry, in order to obtain a suitable nano structure. The deposition mechanism was determined as instantaneous nucleation and the dimension of particles was controlled in nanometric particle size range. Atomic Force Microscope was used to evaluate the effect of cysteine on the morphology and topography of gold nanoparticles. Finally the catalytic property of gold nanoparticle electrodeposited was studied in KOH solution, where oxygen reduction on the gold nanoparticle surface was eight times greater than that on the conventional gold deposits.

  8. Single layer porous gold films grown at different temperatures

    International Nuclear Information System (INIS)

    Zhang Renyun; Hummelgard, Magnus; Olin, Hakan

    2010-01-01

    Large area porous gold films can be used in several areas including electrochemical electrodes, as an essential component in sensors, or as a conducting material in electronics. Here, we report on evaporation induced crystal growth of large area porous gold films at 20, 40 and 60 deg. C. The gold films were grown on liquid surface at 20 deg. C, while the films were grown on the wall of beakers when temperature increased to 40 and 60 deg. C. The porous gold films consisted of a dense network of gold nanowires as characterized by TEM and SEM. TEM diffraction results indicated that higher temperature formed larger crystallites of gold wires. An in situ TEM imaging of the coalescence of gold nanoparticles mimicked the process of the growth of these porous films, and a plotting of the coalescence time and the neck radius showed a diffusion process. The densities of these gold films were also characterized by transmittance, and the results showed film grown at 20 deg. C had the highest density, while the film grown at 60 deg. C had the lowest consistent with SEM and TEM characterization. Electrical measurements of these gold films showed that the most conductive films were the ones grown at 40 deg. C. The conductivities of the gold films were related to the amount of contamination, density and the diameter of the gold nanowires in the films. In addition, a gold film/gold nanoparticle hybrid was made, which showed a 10% decrease in transmittance during hybridization, pointing to applications as chemical and biological sensors.

  9. Report on NIM-NMC bilateral comparison: SPRT calibration comparison from -190°C to 420°C

    Science.gov (United States)

    Sun, Jianping; Ye, Shaochun; Wang, Li; Zhang, Jintao; Kho, Haoyuan

    2016-01-01

    A bilateral comparison of local realization of the International temperature scale of 1990 (ITS-90) between National Institute of Metrology (NIM) and National Metrology Centre (NMC) was carried out over the temperature range from -190°C to 420°C. It involved six fixed points including the argon triple point, the mercury triple point, the triple point of water, the melting point of gallium, the freezing point of tin and the freezing point of zinc. In 2009, NMC asked NIM to participate in a bilateral comparison to link the NMC results to the Consultative Committee for Thermometry Key comparison 3 (CCT-K3) and facilitate the NMC's Calibration and measurement capabilities (CMCs) submission. This comparison was agreed by NIM and Asia Pacific Metrology Programme (APMP) in 2009, and registered in the Key Comparison Database (KCDB) in 2010 as CCT-K3.2. NMC supplied two 25 Ω fused silica sheath standard platinum resistance thermometers (SPRTs) as traveling standards. One of them was used at the Ga, Sn and Zn fixed points, while the other one was used at the Ar and Hg fixed point. NMC measured them before and after NIM measurement. During the comparison, a criterion for the SPRT was set as the stability at the triple point of water to be less than 0.3 mK. The results for both laboratories are summarized. A proposal for linking the NMC's comparison results to CCT-K3 is presented. The difference between NMC and NIM and the difference between NMC and the CCT-K3 Average Reference Value (ARV) using NIM as a link are reported with expanded uncertainties at each measured fixed point. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  10. Influence of i13/2 proton and j15/2 neutron intruding orbitals on the behaviour of 190 mass region superdeformed nuclei

    International Nuclear Information System (INIS)

    Duprat, J.

    1995-01-01

    This work concerns the study of the nuclear superdeformation phenomenon in the A = 190 mass region. The superdeformed (SD) states in 193 Tl, 194 Tl 195 Tl were produced via heavy-ion induced reactions and studied with the EUROGAM gamma multidetector array. The analysis of high-multiplicity events allowed the study of the magnetic properties of the SD states in these nuclei. For the first time, the g-factor of a proton orbital in a SD nucleus in the A = 190 mass region has been extracted. This measurement indicates that the two known bands in 195 Tl-SD are built on the i 13/2 proton intruder orbital. A new SD band has been found in this isotope: it is the first SD band built on an excited proton state found in the A = 190 region. Finally an interaction between two pairs of bands has been established in 194 Tl; this interaction indicate the crossing of two neutron orbitals above the N = 112 gap. The magnetic properties of the states of the SD bands in 194 Tl reveals that these bands are built on configurations in which the single proton and neutron intrinsic spins are aligned. Comparison between different SD bands in the Thallium isotopes shows the prominent role of the i 13/2 proton and the j 15/2 neutron intruder orbitals in the smooth increase of the dynamical moment of inertia as a function of the rotational frequency. In addition, this work reports on the first observation of a SD rotational band produced in a (HI, αxn) reaction channel. The study of the maximum spin reached by the SD bands indicates both a competition between alpha emission and fission of the compound nucleus, and the limitation due to the fission process in the population of the SD nuclei in the A = 190 region. (author). 120 refs., 112 figs., 22 tabs., 2 ann

  11. Excitation energy dependence of fragment-mass distributions from fission of 180,190Hg formed in fusion reactions of 36Ar + 144,154Sm

    Directory of Open Access Journals (Sweden)

    K. Nishio

    2015-09-01

    Full Text Available Mass distributions of fission fragments from the compound nuclei 180Hg and 190Hg formed in fusion reactions 36Ar + 144Sm and 36Ar + 154Sm, respectively, were measured at initial excitation energies of E⁎(Hg180=33–66 MeV and E⁎(Hg190=48–71 MeV. In the fission of 180Hg, the mass spectra were well reproduced by assuming only an asymmetric-mass division, with most probable light and heavy fragment masses A¯L/A¯H=79/101. The mass asymmetry for 180Hg agrees well with that obtained in the low-energy β+/EC-delayed fission of 180Tl, from our earlier ISOLDE(CERN experiment. Fission of 190Hg is found to proceed in a similar way, delivering the mass asymmetry of A¯L/A¯H=83/107, throughout the measured excitation energy range. The persistence as a function of excitation energy of the mass-asymmetric fission for both proton-rich Hg isotopes gives strong evidence for the survival of microscopic effects up to effective excitation energies of compound nuclei as high as 40 MeV. This behavior is different from fission of actinide nuclei and heavier mercury isotope 198Hg.

  12. Accuracy and calibration of integrated radiation output indicators in diagnostic radiology: A report of the AAPM Imaging Physics Committee Task Group 190

    International Nuclear Information System (INIS)

    Lin, Pei-Jan P.; Schueler, Beth A.; Balter, Stephen; Strauss, Keith J.; Wunderle, Kevin A.; LaFrance, M. Terry; Kim, Don-Soo; Behrman, Richard H.; Shepard, S. Jeff; Bercha, Ishtiaq H.

    2015-01-01

    Due to the proliferation of disciplines employing fluoroscopy as their primary imaging tool and the prolonged extensive use of fluoroscopy in interventional and cardiovascular angiography procedures, “dose-area-product” (DAP) meters were installed to monitor and record the radiation dose delivered to patients. In some cases, the radiation dose or the output value is calculated, rather than measured, using the pertinent radiological parameters and geometrical information. The AAPM Task Group 190 (TG-190) was established to evaluate the accuracy of the DAP meter in 2008. Since then, the term “DAP-meter” has been revised to air kerma-area product (KAP) meter. The charge of TG 190 (Accuracy and Calibration of Integrated Radiation Output Indicators in Diagnostic Radiology) has also been realigned to investigate the “Accuracy and Calibration of Integrated Radiation Output Indicators” which is reflected in the title of the task group, to include situations where the KAP may be acquired with or without the presence of a physical “meter.” To accomplish this goal, validation test protocols were developed to compare the displayed radiation output value to an external measurement. These test protocols were applied to a number of clinical systems to collect information on the accuracy of dose display values in the field

  13. Accuracy and calibration of integrated radiation output indicators in diagnostic radiology: A report of the AAPM Imaging Physics Committee Task Group 190

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Pei-Jan P., E-mail: Pei-Jan.Lin@vcuhealth.org [Virginia Commonwealth University Medical Center, Richmond, Virginia 23298 (United States); Schueler, Beth A. [Mayo Clinic, Rochester, Minnesota 55905 (United States); Balter, Stephen [Columbia University Medical Center, New York, New York 10032 (United States); Strauss, Keith J. [Children’s Hospital Medical Center, Cincinnati, Ohio 45229 (United States); Wunderle, Kevin A. [Cleveland Clinic Foundation, Cleveland, Ohio 44195 (United States); LaFrance, M. Terry [Baystate Health Systems, Inc., Springfield, Massachusetts 01199 (United States); Kim, Don-Soo [Children’s Hospital Boston, Boston, Massachusetts 02115 (United States); Behrman, Richard H. [Boston University Medical Center, Boston, Massachusetts 02118 (United States); Shepard, S. Jeff [University of Texas MD Anderson Cancer Center, Houston, Texas 77096 (United States); Bercha, Ishtiaq H. [Children’s Hospital Colorado, Aurora, Colorado 80045 (United States)

    2015-12-15

    Due to the proliferation of disciplines employing fluoroscopy as their primary imaging tool and the prolonged extensive use of fluoroscopy in interventional and cardiovascular angiography procedures, “dose-area-product” (DAP) meters were installed to monitor and record the radiation dose delivered to patients. In some cases, the radiation dose or the output value is calculated, rather than measured, using the pertinent radiological parameters and geometrical information. The AAPM Task Group 190 (TG-190) was established to evaluate the accuracy of the DAP meter in 2008. Since then, the term “DAP-meter” has been revised to air kerma-area product (KAP) meter. The charge of TG 190 (Accuracy and Calibration of Integrated Radiation Output Indicators in Diagnostic Radiology) has also been realigned to investigate the “Accuracy and Calibration of Integrated Radiation Output Indicators” which is reflected in the title of the task group, to include situations where the KAP may be acquired with or without the presence of a physical “meter.” To accomplish this goal, validation test protocols were developed to compare the displayed radiation output value to an external measurement. These test protocols were applied to a number of clinical systems to collect information on the accuracy of dose display values in the field.

  14. Modified gold electrodes based on thiocytosine/guanine-gold nanoparticles for uric and ascorbic acid determination

    International Nuclear Information System (INIS)

    Vulcu, Adriana; Grosan, Camelia; Muresan, Liana Maria; Pruneanu, Stela; Olenic, Liliana

    2013-01-01

    The present paper describes the preparation of new modified surfaces for electrodes based on guanine/thiocytosine and gold nanoparticles. The gold nanoparticles were analyzed by UV–vis spectroscopy and transmission electron microscopy (TEM) and it was found that they have diameters between 30 and 40 nm. The layers were characterized by specular reflectance infrared spectroscopy (FTIR-RAS) and by atomic force microscopy (AFM). The thickness of layers was found to be approximately 30 nm for TC layers and 300 nm for GU layers. Every layer was characterized as electrochemical sensor (by cyclic voltammetry) both for uric acid and ascorbic acid determinations, separately and in their mixture. The modified sensors have good calibration functions with good sensitivity (between 1.145 and 1.406 mA cm −2 /decade), reproducibility ( t hiocytosine (Au T C) and gold g uanine (Au G U) layers

  15. Metamorphic Rock-Hosted Orogenic Gold Deposit Type as a Source of Langkowala Placer Gold, Bombana, Southeast Sulawesi

    Directory of Open Access Journals (Sweden)

    Arifudin Idrus

    2014-06-01

    Full Text Available DOI: 10.17014/ijog.v6i1.114In 2008, placer gold was discovered in Langkowala area (Bombana Regency, Southeast Sulawesi, Indonesia, and more than 60,000 traditional gold miners in the early 2009 have been operating by digging vertical pits and panning active stream sediments. The grade of placer gold ranges from 50 to 140 g/t. Local geological framework indicates that the placer gold is not related to volcanic rock-related hydrothermal gold deposit, e.g. epithermal, skarn or porphyry. This paper describes a preliminary study on possible primary deposit type as a source of the Langkowala (Bombana secondary placer gold. A field study indicates that the Langkowala (Bombana placer/paleoplacer gold is possibly related to gold-bearing quartz veins/veinlets hosted by metamorphic rocks particularly mica schist and metasediments in the area. These quartz veins/veinlets are currently recognized in metamorphic rocks at Wumbubangka Mountains, a northern flank of Rumbia Mountain Range. Sheared, segmented quartz veins/veinlets are of 2 cm to 2 m in width and contain gold in a grade varying between 2 and 61 g/t. At least, there are two generations of the quartz veins. The first generation of quartz vein is parallel to foliation of mica schist and metasediments with general orientation of N 300oE/60o; the second quartz vein generation crosscut the first quartz vein and the foliation of the wallrock. The first quartz veins are mostly sheared/deformed, brecciated, and occasionally sigmoidal, whereas the second quartz veins are relatively massive. The similar quartz veins/veinlets types are also probably present in Mendoke Mountain Range, in the northern side of Langkowala area. This primary gold deposit is called as ‘orogenic gold type’. The orogenic gold deposit could be a new target of gold exploration in Indonesia in the future.

  16. Gold 100: proceedings of the international conference on gold. V. 1

    International Nuclear Information System (INIS)

    Wagner, H.; King, R.P.

    1986-01-01

    The papers collected in this, the first of three volumes, reflect the tremendous interest in technology of mining as it is applied to the recovery of gold from a variety of orebodies. The emphasis at 'Gold 100' was very largely associated with the problem of deep level mining of tabular orebodies and the challenges facing the mining engineer. The technical problems created by the need to overcome the threat of ever-increasing costs as the mines enter an increasingly hostile and difficult environment are prominent in the papers collected in this volume. The material collected here reflects the remarkable improvements in technology now taking place

  17. Formation of neutral and charged gold carbonyls on highly facetted gold nanostructures

    Science.gov (United States)

    Chau, Thoi-Dai; Visart de Bocarmé, Thierry; Kruse, Norbert; Wang, Richard L. C.; Kreuzer, Hans Jürgen

    2003-12-01

    We show that gold mono- and di-carbonyls are formed on gold field emitter tips during interaction with carbon monoxide gas at room temperature and in the presence of high electrostatic fields. The experiments are done in a time-of-flight atom probe to obtain mass spectra. The yield of monocarbonyl cations is about twice that of di-carbonyl ions. Density functional theory calculations are reported that explain the field stabilization of adsorbed carbonyls and the desorption yield of their cations.

  18. Ion induced segregation in gold nanostructured thin films on silicon

    International Nuclear Information System (INIS)

    Ghatak, J.; Satyam, P.V.

    2008-01-01

    We report a direct observation of segregation of gold atoms to the near surface regime due to 1.5 MeV Au 2+ ion impact on isolated gold nanostructures deposited on silicon. Irradiation at fluences of 6 x 10 13 , 1 x 10 14 and 5 x 10 14 ions cm -2 at a high beam flux of 6.3 x 10 12 ions cm -2 s -1 show a maximum transported distance of gold atoms into the silicon substrate to be 60, 45 and 23 nm, respectively. At a lower fluence (6 x 10 13 ions cm -2 ) transport has been found to be associated with the formation of gold silicide (Au 5 Si 2 ). At a high fluence value of 5 x 10 14 ions cm -2 , disassociation of gold silicide and out-diffusion lead to the segregation of gold to defect - rich surface and interface regions.

  19. Phospholipid-assisted synthesis of size-controlled gold nanoparticles

    International Nuclear Information System (INIS)

    He Peng; Zhu Xinyuan

    2007-01-01

    Morphology and size control of gold nanoparticles (AuNPs) by phospholipids (PLs) has been reported. It was found that gold entities could form nanostructures with different sizes controlled by PLs in an aqueous solution. During the preparation of 1.5 nm gold seeds, AuNPs were obtained from the reduction of gold complex by sodium borohydride and capped by citrate for stabilization. With the different ratios between seed solution and growth solution, which was composed by gold complex and PLs, gold seeds grew into larger nanoparticles step by step until enough large size up to 30 nm. The main discovery of this work is that common biomolecules, such as PLs can be used to control nanoparticle size. This conclusion has been confirmed by transmission electron micrographs, particle size analysis, and UV-vis spectra

  20. Corrosion of gold alloys and titanium in artificial saliva

    International Nuclear Information System (INIS)

    Brune, D.; Evje, D.

    1982-01-01

    Two types of gold alloys and one type of pure titanium have been submitted to corrosion in artificial saliva for periods of up to about 2 months. The release of copper, gold and silver from the gold alloys as well as titanium from the titanium matrix was measured with nuclear tracer technique. The physical/chemical state of the corrosion products of gold alloys referring to the ionic state or presence in particulate form has been examined retaining the particulate matter on a glass filter. Copper was observed to be mainly present in the ionic state. Considerable amounts of gold were observed to be retained on the glass filter explained by the presence of gold in particulate form or as a compentent of a dispersed collloidal phase. The estimation of the release of titanium was registered by the tracer nuclide 46 Sc assuming particulate matter to be deteriorated from the titanium surface. (author)

  1. An application of gold diffusion for defect investigation in silicon

    International Nuclear Information System (INIS)

    Feklisova, O.V.; Yakimov, E.B.

    2009-01-01

    The application of gold diffusion for defect investigation in Si is illustrated by the diffusion experiments carried out on crystals containing grown-in or specially introduced defects. The efficiency of gold diffusion experiments for monitoring the concentration and spatial distribution of these defects is shown. The effect of vacancy type defects on gold diffusion is illustrated by investigations of nitrogen-doped FZ Si and of Cz Si after rapid thermal annealing. In both these cases the gold depth profile is distinctive for trap limited diffusion. The effect of sinks for self-interstitials on gold diffusion is illustrated by the results obtained on the plastically deformed Si. It is shown that in silicon deformed at relatively low temperatures the gold diffusion is to a great extent determined by the defects in the dislocation trails while in high temperature deformed Si the sinks for self-interstitials are associated with dislocations themselves.

  2. Establishment of gold-quartz standard GQS-1

    Science.gov (United States)

    Millard, Hugh T.; Marinenko, John; McLane, John E.

    1969-01-01

    A homogeneous gold-quartz standard, GQS-1, was prepared from a heterogeneous gold-bearing quartz by chemical treatment. The concentration of gold in GQS-1 was determined by both instrumental neutron activation analysis and radioisotope dilution analysis to be 2.61?0.10 parts per million. Analysis of 10 samples of the standard by both instrumental neutron activation analysis and radioisotope dilution analysis failed to reveal heterogeneity within the standard. The precision of the analytical methods, expressed as standard error, was approximately 0.1 part per million. The analytical data were also used to estimate the average size of gold particles. The chemical treatment apparently reduced the average diameter of the gold particles by at least an order of magnitude and increased the concentration of gold grains by a factor of at least 4,000.

  3. Photochemical Synthesis of the Bioconjugate Folic Acid-Gold Nanoparticles

    DEFF Research Database (Denmark)

    León, John Jairo Castillo; Bertel, Linda; Páez-Mozo, Edgar

    2013-01-01

    In this paper we present a rapid and simple onepot method to obtain gold nanoparticles functionalized with folic acid using a photochemistry method. The bioconjugate folic acid-gold nanoparticle was generated in one step using a photo-reduction method, mixing hydrogen tetrachloroaurate with folic...... at 4°C prolongs the stability of folic acid-gold nanoparticle suspensions to up to 26 days. Ultraviolet visible and Fourier transform infrared spectroscopy showed a surface plasmon band of around 534nm and fluorescence spectroscopy exhibited a quenching effect on gold nanoparticles in the fluorescence...... emission of folic acid and thus confirmed the conjugation of folic acid to the surface of gold nanoparticles. In this study we demonstrate the use of a photochemistry method to obtain folic acid-gold nanoparticles in a simple and rapid way without the use of surfactants and long reaction times...

  4. Stability of gold atoms and dimers adsorbed on graphene

    International Nuclear Information System (INIS)

    Varns, R; Strange, P

    2008-01-01

    We report density functional theory (DFT) calculations for gold atoms and dimers on the surface of graphene. The calculations were performed using the plane wave pseudopotential method. Calculations were performed for a variety of geometries, and both the graphene surface and gold atoms were allowed to fully relax. In agreement with experiment, our results show that the gold-gold interaction is considerably stronger than the gold-graphene interaction, implying that uniform coverage could not be attained. The minimum energy configuration for a single gold atom is found to be directly above a carbon atom, while for the dimer it is perpendicular to the surface and directly above a carbon-carbon bond. Our results are consistent with previous similar calculations

  5. Diatom. A potential bio-accumulator of gold

    International Nuclear Information System (INIS)

    Chakraborty, N.; Pal, R.; Ramaswami, A.; Nayak, D.; Lahiri, S.

    2006-01-01

    The bioaccumulation of gold in trace concentration by Nitzschia obtusa and Navicula minima, two members of bacillariophyceae, has been studied. It has been observed that Nitzschia obtusa showed better accumulation of gold in acidic pH in comparison to neutral and basic pH. Maximum accumulation was observed with 1 mg x kg -1 or less gold concentration. However, the accumulation by the living cells was reduced when the matrix concentration was higher. Navicula minima, on the other hand, found to be a better accumulator of gold in wide ranges of pH and substrate concentration of the media. It was also inferred that the gold accumulation by diatom was mainly due to adsorption by biosilica (siliceous frustules of dead diatom cells). Accumulated gold was recovered with conc. HNO 3 . (author)

  6. Thiosulphate leaching of gold-, silver-, copper flotation concentrates

    International Nuclear Information System (INIS)

    Samikhov, Sh.R.; Zinchenko, Z.A.

    2015-01-01

    Present article is devoted to thiosulphate leaching of gold-, silver-, copper flotation concentrates. For the purpose to improve the process of thiosulphate leaching the ore samples were calcined at temperature 600 ℃ during two hours. During the calcination process of gold-sulphide ores and concentrates the minerals pyrite and arsenopyrite oxidize which lead to opening of gold contains in them. It was defined that thiosulphate leaching can be recommended as an alternative to cyanic process.

  7. Determination of Commercial Karats on Gold Alloys for Jewellery

    International Nuclear Information System (INIS)

    Morales, S.E.A.

    1986-12-01

    An XRF method for the gold content determination in gold alloys was proposed and tested. Gold coins and ingot samples were analyzed. Monoelemental standards and two pint regression curves calculated with the NBSGSC program, Cd-109 annular source, Si-Li detector, 4096 channels analyzer and AXIL deconvolution software were employed. Good precision better than 1.5% and accuracy better than 2% were obtained. (author)

  8. Photonics of 2D gold nanolayers on sapphire surface

    Energy Technology Data Exchange (ETDEWEB)

    Muslimov, A. E., E-mail: amuslimov@mail.ru; Butashin, A. V.; Nabatov, B. V. [Russian Academy of Sciences, Shubnikov Institute of Crystallography, Federal Research Center “Crystallography and Photonics” (Russian Federation); Konovko, A. A.; Belov, I. V.; Gizetdinov, R. M.; Andreev, A. V. [Moscow State University (Russian Federation); Kanevsky, V. M. [Russian Academy of Sciences, Shubnikov Institute of Crystallography, Federal Research Center “Crystallography and Photonics” (Russian Federation)

    2017-03-15

    Gold layers with thicknesses of up to several nanometers, including ordered and disordered 2D nanostructures of gold particles, have been formed on sapphire substrates; their morphology is described; and optical investigations are carried out. The possibility of increasing the accuracy of predicting the optical properties of gold layers and 2D nanostructures using quantum-mechanical models based on functional density theory calculation techniques is considered. The application potential of the obtained materials in photonics is estimated.

  9. Biosynthesis of Silver and Gold Crystals Using Grapefruit Extract

    OpenAIRE

    Chen Long; Wang Jianli; Wang Hongfeng; Qi Zhaopeng; Zheng Yuchuan; Wang Junbo; Pan Le; Chang Guanru; Yang Yongmei

    2016-01-01

    In this paper, biological synthesis of silver and gold crystals using grapefruit extract is reported. On treatment of aqueous solutions of silver nitrate and chloroauric acid with grapefruit extract, the formation of stable silver and gold particles at high concentrations is observed to occur. The silver particles formed are quasi-spherical or irregular with sizes ranging from several hundred nanometers to several microns. The gold quasi-spheres with holes on surfaces and with diameters rangi...

  10. Synthesis of porous gold nanoshells by controlled transmetallation reaction

    Energy Technology Data Exchange (ETDEWEB)

    Pattabi, Manjunatha, E-mail: manjupattabi@yahoo.com; M, Krishnaprabha [Department of Materials Science, Mangalore University, Mangalagangothri-574199 (India)

    2015-06-24

    Aqueous synthesis of porous gold nanoshells in one step is carried out through controlled transmetallation (TM) reaction using a naturally available egg shell membrane (ESM) as a barrier between the sacrificial silver particles (AgNPs) and the gold precursor solution (HAuCl{sub 4}). The formation of porous gold nanoshells via TM reaction is inferred from UV-Vis spectroscopy and the scanning electron microscopic (SEM) studies.

  11. Site-Specific Biomolecule Labeling with Gold Clusters

    Science.gov (United States)

    Ackerson, Christopher J.; Powell, Richard D.; Hainfeld, James F.

    2013-01-01

    Site-specific labeling of biomolecules in vitro with gold clusters can enhance the information content of electron cryomicroscopy experiments. This chapter provides a practical overview of well-established techniques for forming biomolecule/gold cluster conjugates. Three bioconjugation chemistries are covered: Linker-mediated bioconjugation, direct gold–biomolecule bonding, and coordination-mediated bonding of nickel(II) nitrilotriacetic acid (NTA)-derivatized gold clusters to polyhistidine (His)-tagged proteins. PMID:20887859

  12. Site-Specific Biomolecule Labeling with Gold Clusters

    OpenAIRE

    Ackerson, Christopher J.; Powell, Richard D.; Hainfeld, James F.

    2010-01-01

    Site-specific labeling of biomolecules in vitro with gold clusters can enhance the information content of electron cryomicroscopy experiments. This chapter provides a practical overview of well-established techniques for forming biomolecule/gold cluster conjugates. Three bioconjugation chemistries are covered: Linker-mediated bioconjugation, direct gold–biomolecule bonding, and coordination-mediated bonding of nickel(II) nitrilotriacetic acid (NTA)-derivatized gold clusters to polyhistidine (...

  13. Forecasting the price of gold: An error correction approach

    Directory of Open Access Journals (Sweden)

    Kausik Gangopadhyay

    2016-03-01

    Full Text Available Gold prices in the Indian market may be influenced by a multitude of factors such as the value of gold in investment decisions, as an inflation hedge, and in consumption motives. We develop a model to explain and forecast gold prices in India, using a vector error correction model. We identify investment decision and inflation hedge as prime movers of the data. We also present out-of-sample forecasts of our model and the related properties.

  14. Applications of Gold Nanoparticles in Nanomedicine: Recent Advances in Vaccines.

    Science.gov (United States)

    Carabineiro, Sónia Alexandra Correia

    2017-05-22

    Nowadays, gold is used in (nano-)medicine, usually in the form of nanoparticles, due to the solid proofs given of its therapeutic effects on several diseases. Gold also plays an important role in the vaccine field as an adjuvant and a carrier, reducing toxicity, enhancing immunogenic activity, and providing stability in storage. An even brighter golden future is expected for gold applications in this area.

  15. The comparative effect of wrapping solid gold nanoparticles and hollow gold nanoparticles with doxorubicin-loaded thermosensitive liposomes for cancer thermo-chemotherapy.

    Science.gov (United States)

    Li, Yanan; He, Dongsheng; Tu, Jiasheng; Wang, Ru; Zu, Chang; Chen, You; Yang, Wenqian; Shi, Di; Webster, Thomas J; Shen, Yan

    2018-04-26

    Since conventional chemotherapy is a systemic treatment that affects the body globally and will not concentrate inside the tumor, it causes adverse side effects to patients. In this study, doxorubicin (DOX) together with solid gold nanoparticles (GNPs) or hollow gold nanoparticles (HGNPs), respectively, is loaded inside thermosensitive liposomes (GNPs&DOX-TLs and HGNPs&DOX-TLs), where the GNPs and HGNPs act as a "nanoswitch" for killing tumor cells directly by hyperthermia and triggering DOX release from TLs in the tumor quickly by near infrared laser (NIR) illumination. In addition, this study investigated the photothermal transformation ability, NIR triggered drug release behavior, and the intracellular uptake and cytotoxicity of breast tumor cells and the thermo-chemotherapy mediated by the co-delivery of GNPs&DOX-TLs and HGNPs&DOX-TLs. GNPs and HGNPs had very different light-to-heat transduction efficiencies, while the hollow HGNPs had the advantage of NIR surface plasmon tunability, resulting in the photothermal ablation of tumors with 800 nm light penetration in tissue. The prepared HGNPs&DOX-TLs exhibited a spherical shape with a diameter of 190 nm and a ξ potential of -29 mV, which were steadily dispersed for at least one month. The co-encapsulated DOX was released under hyperthermia caused by NIR-responsive HGNPs and the local drug concentration increased along with the disintegration of the liposomal membrane. This co-delivery of HGNPs&DOX-TLs produced a synergistic cytotoxicity response, thereby enhancing anticancer efficacy 8-fold and increasing the survival time compared to GNPs&DOX-TLs. This work suggested that the co-delivery of HGNPs&DOX-TLs followed by burst-release of DOX using NIR-responsive HGNPs sensitized cancer cells to the chemotherapeutic compound, which provided a novel concept for the combination strategy of chemotherapy and photothermal therapy. These results suggest that the markedly improved therapeutic efficacy and decreased systemic

  16. Assessment of modified gold surfaced titanium implants on skeletal fixation

    DEFF Research Database (Denmark)

    Zainali, Kasra; Danscher, Gorm; Jakobsen, Thomas

    2013-01-01

    shown to liberate gold ions through the process termed dissolucytosis. Furthermore, gold ions are known to act in an anti-inflammatory manner by inhibiting cellular NF-κB-DNA binding. The present study investigated whether partial coating of titanium implants could augment early osseointegration...... and increase mechanical fixation. Cylindrical porous coated Ti-6Al4V implants partially coated with metallic gold were inserted in the proximal region of the humerus in ten canines and control implants without gold were inserted in contralateral humerus. Observation time was 4 weeks. Biomechanical push out...

  17. Effects of gold coating on experimental implant fixation

    DEFF Research Database (Denmark)

    Zainali, Kasra; Danscher, Gorm; Jakobsen, Thomas

    2009-01-01

    Insertions of orthopedic implants are traumatic procedures that trigger an inflammatory response. Macrophages have been shown to liberate gold ions from metallic gold. Gold ions are known to act in an antiinflammatory manner by inhibiting cellular NF-kappa B-DNA binding and suppressing I-kappa B......-kinase activation. The present study investigated whether gilding implant Surfaces augmented early implant osseointegration and implant fixation by its modulatory effect on the local inflammatory response. Ion release was traced by autometallographic silver enhancement. Gold-coated cylindrical porous coated Ti6Al4V...

  18. Recovering gold from thiosulfate leach pulps via ion exchange

    Science.gov (United States)

    Nicol, Michael J.; O'Malley, Glen

    2002-10-01

    Increasing environmental and occupational safety concerns about the use of cyanide in gold processing has increased interest in more acceptable alternative lixiviants, the most promising of which is thiosulfate. However, the thiosulfate process lacks a proven inpulp method of recovering the dissolved gold because activated carbon is not effective for the absorption of the gold-thiosulfate complex. This paper describes work aimed at evaluating the effectiveness of commercially available anion exchange resins for the recovery of gold from thiosulfate leach liquors and pulps.

  19. ENVIRONMENTAL MONITORING AT THE NALUNAQ GOLD MINE, SOUTH GREENLAND, 2015

    DEFF Research Database (Denmark)

    Bach, Lis; Birch Larsen, Morten

    the monitoring in 2014, the area has been without any activity. The mining company Angel Mining Gold A/S closed its gold production in November 2013 where after the Nalunaq area was affected by decommissioning and restoration until August 2014. The gold was extracted by chemical extraction with cyanide (carbon......-in-pulp). Due to the use of cyanide to extract gold from the ore, there was strict monitoring with the outflow of cyanide from the mine to the valley during the production period, and monitoring will continue for 5 years after the closure. Also, extensive monitoring is conducted to reveal release of metals...

  20. Thiosulfate leaching of gold from waste mobile phones.

    Science.gov (United States)

    Ha, Vinh Hung; Lee, Jae-chun; Jeong, Jinki; Hai, Huynh Trung; Jha, Manis K

    2010-06-15

    The present communication deals with the leaching of gold from the printed circuit boards (PCBs) of waste mobile phones using an effective and less hazardous system, i.e., a copper-ammonia-thiosulfate solution, as an alternative to the conventional and toxic cyanide leaching of gold. The influence of thiosulfate, ammonia and copper sulfate concentrations on the leaching of gold from PCBs of waste mobile phones was investigated. Gold extraction was found to be enhanced with solutions containing 15-20 mM cupric, 0.1-0.14 M thiosulfate, and 0.2-0.3 M ammonia. Similar trends were obtained for the leaching of gold from two different types of scraps and PCBs of waste mobile phones. From the scrap samples, 98% of the gold was leached out using a solution containing 20 mM copper, 0.12 M thiosulfate and 0.2 M ammonia. Similarly, the leaching of gold from the PCBs samples was also found to be good, but it was lower than that of scrap samples in similar experimental conditions. In this case, only 90% of the gold was leached, even with a contact time of 10h. The obtained data will be useful for the development of processes for the recycling of gold from waste mobile phones. Copyright 2010 Elsevier B.V. All rights reserved.

  1. Accumulation of gold using Baker's yeast, Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Roy, Kamalika; Lahiri, Susanta; Sinha, P.

    2006-01-01

    Authors have reported preconcentration of 152 Eu, a long-lived fission product, by yeast cells, Saccharomyces cerevisiae. Gold being a precious metal is used in electroplating, hydrogenation catalyst, etc. Heterogeneous composition of samples and low concentration offers renewed interest in its selective extraction of gold using various extractants. Gold can be recovered from different solutions using various chemical reagents like amines, organophosphorus compounds, and extractants containing sulphur as donor atom, etc. In the present work, two different strains of baker's yeast, Saccharomyces cerevisiae have been used to study the preconcentration of gold at various experimental conditions

  2. Porous Gold Films Fabricated by Wet-Chemistry Processes

    Directory of Open Access Journals (Sweden)

    Aymeric Pastre

    2016-01-01

    Full Text Available Porous gold films presented in this paper are formed by combining gold electroless deposition and polystyrene beads templating methods. This original approach allows the formation of conductive films (2 × 106 (Ω·cm−1 with tailored and interconnected porosity. The porous gold film was deposited up to 1.2 μm on the silicon substrate without delamination. An original zirconia gel matrix containing gold nanoparticles deposited on the substrate acts both as an adhesion layer through the creation of covalent bonds and as a seed layer for the metallic gold film growth. Dip-coating parameters and gold electroless deposition kinetics have been optimized in order to create a three-dimensional network of 20 nm wide pores separated by 20 nm thick continuous gold layers. The resulting porous gold films were characterized by GIXRD, SEM, krypton adsorption-desorption, and 4-point probes method. The process is adaptable to different pore sizes and based on wet-chemistry. Consequently, the porous gold films presented in this paper can be used in a wide range of applications such as sensing, catalysis, optics, or electronics.

  3. GOLD NANOPARTICLES: A REVIVAL IN PRECIOUS METAL ADMINISTRATION TO PATIENTS

    Science.gov (United States)

    Thakor, AS; Jokerst, J; Zaveleta, C; Massoud, TF; Gambhir, SS

    2011-01-01

    Gold has been used as a therapeutic agent to treat a wide variety of rheumatic diseases including psoriatic arthritis, juvenile arthritis and discoid lupus erythematosus. Although the use of gold has been largely superseded by newer drugs, gold nanoparticles are being used effectively in laboratory based clinical diagnostic methods whilst concurrently showing great promise in vivo either as a diagnostic imaging agent or a therapeutic agent. For these reasons, gold nanoparticles are therefore well placed to enter mainstream clinical practice in the near future. Hence, the present review summarizes the chemistry, pharmacokinetics, bio-distribution, metabolism and toxicity of bulk gold in humans based on decades of clinical observation and experiments in which gold was used to treat patients with rheumatoid arthritis. The beneficial attributes of gold nanoparticles, such as their ease of synthesis, functionalization and shape control are also highlighted demonstrating why gold nanoparticles are an attractive target for further development and optimization. The importance of controlling the size and shape of gold nanoparticles to minimize any potential toxic side effects is also discussed. PMID:21846107

  4. Some developments in the extraction of gold from Witwatersrand ores

    International Nuclear Information System (INIS)

    Laxen, P.A.

    1975-01-01

    The extraction of gold from most ores of the Witwatersrand has been consistently high - approximately 95 per cent - for many years. The present high price of gold has stimulated research and development into potential improvements of the standard procedures. The occurrence of the gold and its association with other minerals is described briefly. The Witwatersrand reefs also contain uranium and pyrite, and some of the improvements to the standard gold-extraction process are associated with the recovery or concentration of one or both of these valuable constituents. For instance, the 'reverse-leach' process, in which acid treatment for the extraction of uranium precedes cyanidation, results in improved gold extraction. Some concentration techniques used on the present residues from cyanidation offer promise in improving the overall gold recoveries. Thucholite is an important carrier of residual gold, and its recovery from some residues by flotation appears to be economically justifiable. Wet high-intensity magnetic separation has given promising results, in the laboratory and on the pilot plant, for the recovery of both uranium and gold from a number of cyanide tailings. The benefits of gravity concentration and of the application of empirical modelling to the gold-extraction process have been demonstrated by a mining group. Some developments in instrumentation for control during cyanidation are discussed briefly [af

  5. Fabrication and characterization of gold nanocrown arrays on a gold film for a high-sensitivity surface plasmon resonance biosensor

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Munsik; Kim, Nak-hyeon; Eom, Seyoung [Department of Biomedical Engineering, Kyung Hee University, Yongin 446-701 (Korea, Republic of); Kim, Tae Woo [School of East–West Medical Science, Kyung Hee University, Yongin 446-701 (Korea, Republic of); Byun, Kyung Min, E-mail: kmbyun@khu.ac.kr [Department of Biomedical Engineering, Kyung Hee University, Yongin 446-701 (Korea, Republic of); Park, Hyeong-Ho, E-mail: hyeongho.park@kanc.re.kr [Nano Process Division, Korea Advanced Nano Fab Center, Suwon 443-270 (Korea, Republic of)

    2015-07-31

    We report on a versatile method to fabricate gold nanocrown arrays on a thin gold film based on ultraviolet nanoimprint lithography and tilted evaporation technique. We realize highly ordered 2-dimensional nanocrown arrays and characterize their sizes and morphologies using scanning electron microscopy. To demonstrate an enhanced surface plasmon resonance (SPR) detection by the fabricated gold nanocrown samples, biosensing experiments are performed by measuring SPR angle shift for biotin–streptavidin interaction and bulk refractive index change of dielectric medium. We hope that the suggested plasmonic platform with a high sensitivity could be extended to a variety of biomolecular binding reactions. - Highlights: • Gold nanocrown arrays are produced by nanoimprint lithography and tilted evaporation. • Use of gold nanocrown arrays can improve the sensor sensitivity significantly. • Improved sensitivity is due to enhanced field–matter interaction at gold nanocrowns.

  6. Surface modification of silica particles with gold nanoparticles as an augmentation of gold nanoparticle mediated laser perforation

    Science.gov (United States)

    Kalies, Stefan; Gentemann, Lara; Schomaker, Markus; Heinemann, Dag; Ripken, Tammo; Meyer, Heiko

    2014-01-01

    Gold nanoparticle mediated (GNOME) laser transfection/perforation fulfills the demands of a reliable transfection technique. It provides efficient delivery and has a negligible impact on cell viability. Furthermore, it reaches high-throughput applicability. However, currently only large gold particles (> 80 nm) allow successful GNOME laser perforation, probably due to insufficient sedimentation of smaller gold nanoparticles. The objective of this study is to determine whether this aspect can be addressed by a modification of silica particles with gold nanoparticles. Throughout the analysis, we show that after the attachment of gold nanoparticles to silica particles, comparable or better efficiencies to GNOME laser perforation are reached. In combination with 1 µm silica particles, we report laser perforation with gold nanoparticles with sizes down to 4 nm. Therefore, our investigations have great importance for the future research in and the fields of laser transfection combined with plasmonics. PMID:25136494

  7. Immobilization of gold nanoparticles on cell culture surfaces for safe and enhanced gold nanoparticle-mediated laser transfection

    Science.gov (United States)

    Kalies, Stefan; Heinemann, Dag; Schomaker, Markus; Gentemann, Lara; Meyer, Heiko; Ripken, Tammo

    2014-01-01

    Abstract. In comparison to standard transfection methods, gold nanoparticle-mediated laser transfection has proven to be a versatile alternative. This is based on its minor influence on cell viability and its high efficiency, especially for the delivery of small molecules like small interfering RNA. However, in order to transfer it to routine usage, a safety aspect is of major concern: The avoidance of nanoparticle uptake by the cells is desired. The immobilization of the gold nanoparticles on cell culture surfaces can address this issue. In this study, we achieved this by silanization of the appropriate surfaces and the binding of gold nanoparticles to them. Comparable perforation efficiencies to the previous approaches of gold nanoparticle-mediated laser transfection with free gold nanoparticles are demonstrated. The uptake of the immobilized particles by the cells is unlikely. Consequently, these investigations offer the possibility of bringing gold nanoparticle-mediated laser transfection closer to routine usage. PMID:25069006

  8. Amoxicillin functionalized gold nanoparticles reverts MRSA resistance

    International Nuclear Information System (INIS)

    Kalita, Sanjeeb; Kandimalla, Raghuram; Sharma, Kaustav Kalyan; Kataki, Amal Chandra; Deka, Manab; Kotoky, Jibon

    2016-01-01

    In this study, we have described the biosynthesis of biocompatible gold nanoparticles (GNPs) from aqueous extract of the aerial parts of a pteridophyte, “Adiantum philippense” by microwave irradiation and its surface functionalization with broad spectrum beta lactam antibiotic, amoxicillin (Amox). The functionalization of amoxicillin on GNPs (GNP-Amox) was carried out via electrostatic interaction of protonated amino group and thioether moiety mediated attractive forces. The synthesized GNPs and GNP-Amox were physicochemically characterized. UV–Vis spectroscopy, Zeta potential, XRD, FTIR and SERS (surface enhanced raman spectra) results confirmed the loading of Amox into GNPs. Loading of Amox to GNPs reduce amoxicillin cytotoxicity, whereas GNPs were found to be nontoxic to mouse fibroblast cell line (L929) as evident from MTT and acridine orange/ethidium bromide (AO/EtBr) live/dead cell assays. The GNP-Amox conjugates demonstrated enhanced broad-spectrum bactericidal activity against both Gram-positive and Gram-negative bacteria. Furthermore, in-vitro and in-vivo assays of GNP-Amox revealed potent anti-MRSA activity and improved the survival rate. This indicates the subversion of antibiotic resistance mechanism by overcoming the effect of high levels of β-lactamase produced by methicillin resistant Staphylococcus aureus (MRSA). Taken together, this study demonstrates the positive attributes from GNP-Amox conjugates as a promising antibacterial therapeutic agent against MRSA as well as other pathogens. - Highlights: • Aqueous extract of A. phillippens was used as a reducing and capping agent for synthesis of microwave irradiated gold nanoparticles. • GNPs were loaded with amoxicillin for restoration in antibacterial activity of amoxicillin against MRSA strains. • Gold nanoparticles and GNP-Amox were found biocompitable as tested on L929 cell line. • The nanoparticle antibiotic conjugates exhibited restoration of amoxicillin activity against MRSA in

  9. Amoxicillin functionalized gold nanoparticles reverts MRSA resistance

    Energy Technology Data Exchange (ETDEWEB)

    Kalita, Sanjeeb; Kandimalla, Raghuram; Sharma, Kaustav Kalyan [Drug Discovery Lab, Life Science Division, Institute of Advanced Study in Science and Technology (IASST), Paschim Boragaon, Garchuk, Guwahati 781035, Assam (India); Kataki, Amal Chandra [Dr. B. Borooah Cancer Institute, Guwahati, Assam (India); Department of Applied Sciences, Gopinath Bordoloi Nagar, Jalukbari, Gauhati University, Guwahati 781014, Assam (India); Deka, Manab [Department of Applied Sciences, Gopinath Bordoloi Nagar, Jalukbari, Gauhati University, Guwahati 781014, Assam (India); Kotoky, Jibon, E-mail: jkotoky@gmail.com [Drug Discovery Lab, Life Science Division, Institute of Advanced Study in Science and Technology (IASST), Paschim Boragaon, Garchuk, Guwahati 781035, Assam (India)

    2016-04-01

    In this study, we have described the biosynthesis of biocompatible gold nanoparticles (GNPs) from aqueous extract of the aerial parts of a pteridophyte, “Adiantum philippense” by microwave irradiation and its surface functionalization with broad spectrum beta lactam antibiotic, amoxicillin (Amox). The functionalization of amoxicillin on GNPs (GNP-Amox) was carried out via electrostatic interaction of protonated amino group and thioether moiety mediated attractive forces. The synthesized GNPs and GNP-Amox were physicochemically characterized. UV–Vis spectroscopy, Zeta potential, XRD, FTIR and SERS (surface enhanced raman spectra) results confirmed the loading of Amox into GNPs. Loading of Amox to GNPs reduce amoxicillin cytotoxicity, whereas GNPs were found to be nontoxic to mouse fibroblast cell line (L929) as evident from MTT and acridine orange/ethidium bromide (AO/EtBr) live/dead cell assays. The GNP-Amox conjugates demonstrated enhanced broad-spectrum bactericidal activity against both Gram-positive and Gram-negative bacteria. Furthermore, in-vitro and in-vivo assays of GNP-Amox revealed potent anti-MRSA activity and improved the survival rate. This indicates the subversion of antibiotic resistance mechanism by overcoming the effect of high levels of β-lactamase produced by methicillin resistant Staphylococcus aureus (MRSA). Taken together, this study demonstrates the positive attributes from GNP-Amox conjugates as a promising antibacterial therapeutic agent against MRSA as well as other pathogens. - Highlights: • Aqueous extract of A. phillippens was used as a reducing and capping agent for synthesis of microwave irradiated gold nanoparticles. • GNPs were loaded with amoxicillin for restoration in antibacterial activity of amoxicillin against MRSA strains. • Gold nanoparticles and GNP-Amox were found biocompitable as tested on L929 cell line. • The nanoparticle antibiotic conjugates exhibited restoration of amoxicillin activity against MRSA in

  10. Characterization of primary geochemical haloes for gold exploration at the Huanxiangwa gold deposit, China

    NARCIS (Netherlands)

    Wang, Changming; Carranza, E.J.M; Zhang, Shouting; Zhang, Jing; Liu, Xiaoji Liu; Zhang, Da; Sun, Xiang; Duan, Cunji

    2013-01-01

    Recognition of primary geochemical haloes is one of the most important tools for exploring undiscovered mineral resources. This tool is being routinely applied in exploration programs at the Huanxiangwa gold deposit, Xiong'er Mountains, China. Sampling of unweathered rock for multi-element analysis

  11. Quantitative electrical detection of immobilized protein using gold nanoparticles and gold enhancement on a biochip

    International Nuclear Information System (INIS)

    Lei, Kin Fong

    2011-01-01

    Electrical detection of the concentration of protein immobilized on a biochip is demonstrated. The concentration of the direct immobilized protein can be determined by the resistance values measured by an ohm-meter directly. Indium tin oxide interdigitated electrodes were utilized as the detection sites on the biochip. Protein, i.e. antibody, of certain concentration was first immobilized on the detection site. Gold nanoparticles were then applied to indicate the immobilized protein. Since the gold nanoparticles were tiny, a detectable electrical signal could not be generated. Hence, a gold enhancement process was performed for signal amplification. Gold nanoparticles were enlarged physically, such that a conductive metal layer was formed on the detection site. The presence and concentration of protein can be determined by the resistance value across the electrode measured by an ohm-meter. An immobilized protein concentration ranging from 50 to 1000 ng ml −1 can be detected quantitatively by the resistance values from 4300 to 1700 Ω. The proposed technique is potentially extended for the detection of immunoassay on the biochip. Since the protocol of the electrical detection does not involve sophisticated equipment, it can therefore be used for the development of a portable immunoassay device

  12. X-Ray Spectroscopy of Gold Nanoparticles

    Science.gov (United States)

    Nahar, Sultana N.; Montenegro, M.; Pradhan, A. K.; Pitzer, R.

    2009-06-01

    Inner shell transitions, such as 1s-2p, in heavy elements can absorb or produce hard X-rays, and hence are widely used in nanoparticles. Bio-medical research for cancer treatment has been using heavy element nanoparticles, embeded in malignant tumor, for efficient absorption of irradiated X-rays and leading emission of hard X-rays and energetic electrons to kill the surrounding cells. Ejection of a 1s electron during ionization of the element by absorption of a X-ray photon initiates the Auger cascades of emission of photons and electrons. We have investigated gold nanoparticles for the optimal energy range, below the K-edge (1s) ionization threshold, that corresponds to resonant absorption of X-rays with large attenuation coefficients, orders of magnitude higher over the background as well as to that at K-edge threshold. We applied these attenuation coefficients in Monte Carlo simulation to study the intensities of emission of photons and electrons by Auger cascades. The numerical experiments were carried out in a phantom of water cube with a thin layer, 0.1mm/g, of gold nanoparticles 10 cm inside from the surface using the well-known code Geant4. We will present results on photon and electron emission spectra from passing monochromatic X-ray beams at 67 keV, which is the resonant energy for resonant K_{α} lines, at 82 keV, the K-shell ionization threshold, and at 2 MeV where the resonant effect is non-existent. Our findings show a high peak in the gold nanoparticle absorption curve indicating complete absorption of radiation within the gold layer. The photon and electron emission spectra show resonant features. Acknowledgement: Partially supported by a Large Interdisciplinary Grant award of the Ohio State University and NASA APRA program (SNN). The computational work was carried out on the Cray X1 and Itanium 4 cluster at the Ohio Supercomputer Center, Columbus Ohio. "Resonant X-ray Irradiation of High-Z Nanoparticles For Cancer Theranostics" (refereed

  13. Recovery of gold and uranium from calcines

    Energy Technology Data Exchange (ETDEWEB)

    Livesey-Goldblatt, E.

    1981-10-06

    The invention concerns the recovery of non-ferrous metals, such as gold, uranium or the like from iron oxide containing calcines which have the non-ferrous metal present in solid solution and/or encapsulated within the iron oxide. The calcine is reacted, while stirring vigorously, with sulphuric acid or another strong inorganic acid to cause the iron to form the ferric salt. The material obtained is mixed with water and the liquid and solid phases are separated from each other. The non-ferrous metal is then obtained from at least one of these phases by leaching, or the like.

  14. Functional gold nanoparticles for optical affinity biosensing

    Czech Academy of Sciences Publication Activity Database

    Špringer, Tomáš; Chadtová Song, Xue; Ermini, Maria Laura; Lamačová, Josefína; Homola, Jiří

    2017-01-01

    Roč. 409, č. 16 (2017), s. 4087-4097 ISSN 1618-2642 R&D Projects: GA ČR(CZ) GBP205/12/G118 Grant - others:AV ČR(CZ) AP1101 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:67985882 Keywords : Gold nanoparticles * Cancer marker carcinoembryonic antigen * Surface plasmon resonance Subject RIV: FS - Medical Facilities ; Equipment OBOR OECD: Medical laboratory technology (including laboratory samples analysis Impact factor: 3.431, year: 2016

  15. The gold standard: gold nanoparticle libraries to understand the nano-bio interface.

    Science.gov (United States)

    Alkilany, Alaaldin M; Lohse, Samuel E; Murphy, Catherine J

    2013-03-19

    Since the late 1980s, researchers have prepared inorganic nanoparticles of many types--including elemental metals, metal oxides, metal sulfides, metal selenides, and metal tellurides--with excellent control over size and shape. Originally many researchers were primarily interested in exploring the quantum size effects predicted for such materials. Applications of inorganic nanomaterials initially centered on physics, optics, and engineering but have expanded to include biology. Many current nanomaterials can serve as biochemical sensors, contrast agents in cellular or tissue imaging, drug delivery vehicles, or even as therapeutics. In this Account we emphasize that the understanding of how nanomaterials will function in a biological system relies on the knowledge of the interface between biological systems and nanomaterials, the nano-bio interface. Gold nanoparticles can serve as excellent standards to understand more general features of the nano-bio interface because of its many advantages over other inorganic materials. The bulk material is chemically inert, and well-established synthetic methods allow researchers to control its size, shape, and surface chemistry. Gold's background concentration in biological systems is low, which makes it relatively easy to measure it at the part-per-billion level or lower in water. In addition, the large electron density of gold enables relatively simple electron microscopic experiments to localize it within thin sections of cells or tissue. Finally, gold's brilliant optical properties at the nanoscale are tunable with size, shape, and aggregation state and enable many of the promising chemical sensing, imaging, and therapeutic applications. Basic experiments with gold nanoparticles and cells include measuring the toxicity of the particles to cells in in vitro experiments. The species other than gold in the nanoparticle solution can be responsible for the apparent toxicity at a particular dose. Once the identity of the toxic

  16. Gold nanoparticle formation in diamond-like carbon using two different methods: Gold ion implantation and co-deposition of gold and carbon

    International Nuclear Information System (INIS)

    Salvadori, M. C.; Teixeira, F. S.; Araújo, W. W. R.; Sgubin, L. G.; Cattani, M.; Spirin, R. E.; Brown, I. G.

    2012-01-01

    We describe work in which gold nanoparticles were formed in diamond-like carbon (DLC), thereby generating a Au-DLC nanocomposite. A high-quality, hydrogen-free DLC thin film was formed by filtered vacuum arc plasma deposition, into which gold nanoparticles were introduced using two different methods. The first method was gold ion implantation into the DLC film at a number of decreasing ion energies, distributing the gold over a controllable depth range within the DLC. The second method was co-deposition of gold and carbon, using two separate vacuum arc plasma guns with suitably interleaved repetitive pulsing. Transmission electron microscope images show that the size of the gold nanoparticles obtained by ion implantation is 3-5 nm. For the Au-DLC composite obtained by co-deposition, there were two different nanoparticle sizes, most about 2 nm with some 6-7 nm. Raman spectroscopy indicates that the implanted sample contains a smaller fraction of sp 3 bonding for the DLC, demonstrating that some sp 3 bonds are destroyed by the gold implantation.

  17. Improvement of Gold Leaching from a Refractory Gold Concentrate Calcine by Separate Pretreatment of Coarse and Fine Size Fractions

    Directory of Open Access Journals (Sweden)

    Qian Li

    2017-05-01

    Full Text Available A total gold extraction of 70.2% could only be reached via direct cyanidation from a refractory As-, S- and C-bearing gold concentrate calcine, and the gold extraction varied noticeably with different size fractions. The reasons for unsatisfactory gold extraction from the calcine were studied through analyses of chemical composition, chemical phase and SEM-EDS of different sizes of particles. It was found that a significant segregation of compositions occurred during the grinding of gold ore before flotation. As a result, for the calcine obtained after oxidative roasting, the encapsulation of gold by iron oxides was easily engendered in finer particles, whilst in coarser particles the gold encapsulation by silicates was inclined to occur likely due to melted silicates blocking the porosity of particles. The improvement of gold leaching from different size fractions was further investigated through pretreatments with alkali washing, acid pickling or sulfuric acid curing-water leaching. Finally, a novel process was recommended and the total gold extraction from the calcine could be increased substantially to 93.6% by the purposeful pretreatment with alkali washing for the relatively coarse size fraction (+37 μm and sulfuric acid curing–water leaching for the fine size fraction (−37 μm.

  18. Controlled adsorption of cytochrome c to nanostructured gold surfaces

    International Nuclear Information System (INIS)

    Gomes, Inês; Feio, Maria J.; Santos, Nuno C.; Eaton, Peter; Serro, Ana Paula; Saramago, Benilde; Pereira, Eulália; Franco, Ricardo

    2012-01-01

    Controlled electrostatic physisorption of horse heart cytochrome c (Cyt c) onto nanostructured gold surfaces was investigated using Quartz-Crystal Microbalance measurements in planar gold surfaces with or without functionalization using a self-assembled monolayer (SAM) of the alkanethiol mercaptoundecanoic acid (MUA). MUA is a useful functionalization ligand for gold surfaces, shedding adsorbed biomolecules from the excessive electron density of the metal. A parallel analysis was conducted in the corresponding curved surfaces of 15 nm gold nanoparticles (AuNPs), using zeta-potential and UV– visible spectroscopy. Atomic Force Microscopy of both types of functionalized gold surfaces with a MUA SAM, allowed for visualization of Cyt c deposits on the nanostructured gold surface. The amount of Cyt c adsorbed onto the gold surface could be controlled by the solution pH. For the assays conducted at pH 4.5, when MUA SAM- functionalized planar gold surfaces are positive or neutral, and Cyt c has a positive net charge, only 13 % of the planar gold surface area was coated with protein. In contrast, at pH 7.4, when MUA SAM-functionalized planar gold surfaces and Cyt c have opposite charges, a protein coverage of 28 % could be observed implying an adsorption process strongly governed by electrostatic forces. Cyt c adsorption on planar and curved gold surfaces are found to be greatly favored by the presence of a MUA-capping layer. In particular, on the AuNPs, the binding constant is three times larger than the binding constant obtained for the original citrate-capped AuNPs.

  19. Encapsulation of gold nanoparticles into self-assembling protein nanoparticles

    Directory of Open Access Journals (Sweden)

    Yang Yongkun

    2012-10-01

    Full Text Available Abstract Background Gold nanoparticles are useful tools for biological applications due to their attractive physical and chemical properties. Their applications can be further expanded when they are functionalized with biological molecules. The biological molecules not only provide the interfaces for interactions between nanoparticles and biological environment, but also contribute their biological functions to the nanoparticles. Therefore, we used self-assembling protein nanoparticles (SAPNs to encapsulate gold nanoparticles. The protein nanoparticles are formed upon self-assembly of a protein chain that is composed of a pentameric coiled-coil domain at the N-terminus and trimeric coiled-coil domain at the C-terminus. The self-assembling protein nanoparticles form a central cavity of about 10 nm in size, which is ideal for the encapsulation of gold nanoparticles with similar sizes. Results We have used SAPNs to encapsulate several commercially available gold nanoparticles. The hydrodynamic size and the surface coating of gold nanoparticles are two important factors influencing successful encapsulation by the SAPNs. Gold nanoparticles with a hydrodynamic size of less than 15 nm can successfully be encapsulated. Gold nanoparticles with citrate coating appear to have stronger interactions with the proteins, which can interfere with the formation of regular protein nanoparticles. Upon encapsulation gold nanoparticles with polymer coating interfere less strongly with the ability of the SAPNs to assemble into nanoparticles. Although the central cavity of the SAPNs carries an overall charge, the electrostatic interaction appears to be less critical for the efficient encapsulation of gold nanoparticles into the protein nanoparticles. Conclusions The SAPNs can be used to encapsulate gold nanoparticles. The SAPNs can be further functionalized by engineering functional peptides or proteins to either their N- or C-termini. Therefore encapsulation of gold

  20. Controlled adsorption of cytochrome c to nanostructured gold surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Ines [Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, REQUIMTE, Departamento de Quimica (Portugal); Feio, Maria J. [Faculdade de Ciencias da Universidade do Porto, REQUIMTE, Departamento de Quimica e Bioquimica (Portugal); Santos, Nuno C. [Faculdade de Medicina da Universidade de Lisboa, Instituto de Medicina Molecular (Portugal); Eaton, Peter [Faculdade de Ciencias da Universidade do Porto, REQUIMTE, Departamento de Quimica e Bioquimica (Portugal); Serro, Ana Paula; Saramago, Benilde [Centro de Quimica Estrutural, Instituto Superior Tecnico (Portugal); Pereira, Eulalia [Faculdade de Ciencias da Universidade do Porto, REQUIMTE, Departamento de Quimica e Bioquimica (Portugal); Franco, Ricardo, E-mail: ricardo.franco@fct.unl.pt [Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, REQUIMTE, Departamento de Quimica (Portugal)

    2012-12-15

    Controlled electrostatic physisorption of horse heart cytochrome c (Cyt c) onto nanostructured gold surfaces was investigated using Quartz-Crystal Microbalance measurements in planar gold surfaces with or without functionalization using a self-assembled monolayer (SAM) of the alkanethiol mercaptoundecanoic acid (MUA). MUA is a useful functionalization ligand for gold surfaces, shedding adsorbed biomolecules from the excessive electron density of the metal. A parallel analysis was conducted in the corresponding curved surfaces of 15 nm gold nanoparticles (AuNPs), using zeta-potential and UV- visible spectroscopy. Atomic Force Microscopy of both types of functionalized gold surfaces with a MUA SAM, allowed for visualization of Cyt c deposits on the nanostructured gold surface. The amount of Cyt c adsorbed onto the gold surface could be controlled by the solution pH. For the assays conducted at pH 4.5, when MUA SAM- functionalized planar gold surfaces are positive or neutral, and Cyt c has a positive net charge, only 13 % of the planar gold surface area was coated with protein. In contrast, at pH 7.4, when MUA SAM-functionalized planar gold surfaces and Cyt c have opposite charges, a protein coverage of 28 % could be observed implying an adsorption process strongly governed by electrostatic forces. Cyt c adsorption on planar and curved gold surfaces are found to be greatly favored by the presence of a MUA-capping layer. In particular, on the AuNPs, the binding constant is three times larger than the binding constant obtained for the original citrate-capped AuNPs.